Method for making a low density polyethylene waste form for safe disposal of low level radioactive material

DOEpatents

Colombo, P.; Kalb, P.D.

1984-06-05

In the method of the invention low density polyethylene pellets are mixed in a predetermined ratio with radioactive particulate material, then the mixture is fed through a screw-type extruder that melts the low density polyethylene under a predetermined pressure and temperature to form a homogeneous matrix that is extruded and separated into solid monolithic waste forms. The solid waste forms are adapted to be safely handled, stored for a short time, and safely disposed of in approved depositories.

FTIR spectroscopy supported by statistical techniques for the structural characterization of plastic debris in the marine environment: Application to monitoring studies.

PubMed

Mecozzi, Mauro; Pietroletti, Marco; Monakhova, Yulia B

2016-05-15

We inserted 190 FTIR spectra of plastic samples in a digital database and submitted it to Independent Component Analysis (ICA) to extract the "pure" plastic polymers present. These identified plastics were polypropylene (PP), high density polyethylene (HDPE), low density polyethylene (LDPE), high density polyethylene terephthalate (HDPET), low density polyethylene terephthalate (LDPET), polystyrene (PS), Nylon (NL), polyethylene oxide (OPE), and Teflon (TEF) and they were used to establish the similarity with unknown plastics using the correlation coefficient (r), and the crosscorrelation function (CC). For samples with r<0.8 we determined the Mahalanobis Distance (MD) as additional tool of identification. For instance, for the four plastic fragments found in the Carretta carretta, one plastic sample was assigned to OPE due to its r=0.87; for all the other three plastic samples, due to the r values ranging between 0.83 and0.70, the support of MD suggested LDPET and OPE as co-polymer constituents. Copyright © 2016 Elsevier Ltd. All rights reserved.

High density polyethylene pipe fill height table in Arizona.

DOT National Transportation Integrated Search

2006-11-01

This report documents a review of nationwide practices with regard to recommendations for fill heights : over high density polyethylene (HDPE) pipes. Another item of interest to the investigation was typical : use of HDPE pipes by various agencies. T...

High density polyethylene pipe fill height table

DOT National Transportation Integrated Search

2006-11-01

This report documents a review of nationwide practices with regard to recommendations for fill heights over high density polyethylene (HDPE) pipes. Another item of interest to the investigation was typical use of HDPE pipes by various agencies. The b...

Phase structure and properties of poly(ethylene terephthalate)/polyethylene based on recycled materials

Treesearch

Yong Lei; Qinglin Wu; Craig M. Clemons; Weihong Guo

2009-01-01

Blends based on recycled high density polyethylene (R-HDPE) and recycled poly(ethylene terephthalate) (R-PET) were made through reactive extrusion. The effects of maleated polyethylene (PE-g-MA), triblock copolymer of styrene and ethylene/butylene (SEBS), and 4,40-methylenedi(phenyl isocyanate) (MDI) on blend properties were studied. The 2% PE-g-MA improved the...

New plastic recycling technology

EPA Science Inventory

Greater than 60% of the total plastic content of municipal solid waste is comprised of polyolefins (high-density, low-density, and linear polyethylene and polypropylene. Polyethylene (PE) is the largest-volume component but presents a challenge due to the absence of low-energy de...

Ni-coated CaCu3Ti4O12/low density polyethylene composite material with ultra-high dielectric permittivity

NASA Astrophysics Data System (ADS)

Gao, L.; Wang, X.; Chen, Y.; Chi, Q. G.; Lei, Q. Q.

2015-08-01

We report a novel low-density polyethylene (LDPE) composite filled with nickel-coated CaCu3Ti4O12 ceramic (denoted as CCTO@Ni), prepared by a melt mixing technique, and its prominent dielectric characteristics. The effects of magnetic field treatment on the dielectric properties of CCTO@Ni/LDPE composite films with a low filler concentration of 10 vol.% were investigated. Our results show that the dielectric permittivity, loss tangent, and conductivity of the LDPE composite films initially improved and then decreased with increasing treatment time under the applied magnetic field. Magnetic field treatment for 60 min led to an ultra-high dielectric permittivity value of 1.57 × 104, four orders of magnitude higher than that of the pure LDPE material. Our results indicate that the magnetic treatment may have induced a percolation effect and enhanced the interfacial polarization of the CCTO@Ni/LDPE composite, resulting in the observed changes in its dielectric properties.

Zosteric acid and salicylic acid bound to a low density polyethylene surface successfully control bacterial biofilm formation.

PubMed

Cattò, C; James, G; Villa, F; Villa, S; Cappitelli, F

2018-05-04

The active moieties of the anti-biofilm natural compounds zosteric (ZA) and salicylic (SA) acids have been covalently immobilized on a low density polyethylene (LDPE) surface. The grafting procedure provided new non-toxic eco-friendly materials (LDPE-CA and LDPE-SA) with anti-biofilm properties superior to the conventional biocide-based approaches and with features suitable for applications in challenging fields where the use of antimicrobial agents is limited. Microbiological investigation proved that LDPE-CA and LDPE-SA: (1) reduced Escherichia coli biofilm biomass by up to 61% with a mechanism that did not affect bacterial viability; (2) significantly affected biofilm morphology, decreasing biofilm thickness, roughness, substratum coverage, cell and matrix polysaccharide bio-volumes by >80% and increasing the surface to bio-volume ratio; (3) made the biofilm more susceptible to ampicillin and ethanol. Since no molecules were leached from the surface, they remained constantly effective and below the lethal level; therefore, the risk of inducing resistance was minimized.

Solvent-Induced Crystallization in Poly(Ethylene Terephthalate) during Mass Transport

NASA Astrophysics Data System (ADS)

Ouyang, Hao

2001-03-01

The solvent transport in poly(ethylene terephthalate) (PET) and related phase transformation were investigated. The data of mass sorption were analyzed according to Harmon¡¦s model for Case I (Fickian), Case II (swelling) and anomalous transport. This transport process in PET is accompanied by the induced crystallization of the original amorphous state. The transformation was studied by wide angle x-ray scattering (WAXS), small angle x-ray scattering (SAXS), Differential Scanning Calorimeter (DSC), density gradient column, and Fourier Transform Infra-Red (FTIR). During this process, the matrix is under a compressive strain that causes different kinetic path of crystallization as compared to that by thermal annealing. This state of strain will assist the development of the solvent-induced crystallization. It also can be explained in terms of the principle of Le Chatelier if the local equilibrium is assumed. The model regarding the crystallization was proposed in terms of the study of long period L, the crystal thickness lc and the thickness of amorphous layer la, obtained from the linear correlation function and interface distribution function.

Herbicide dissipation from low density polyethylene mulch

USDA-ARS?s Scientific Manuscript database

Field and laboratory studies were conducted to examine herbicide dissipation when applied to low density polyethylene (LDPE) mulch for dry scenarios vs. washing off with water. In field studies, halosulfuron, paraquat, carfentrazone, glyphosate, and flumioxazin were applied to black 1.25-mil LDPE at...

40 CFR 60.561 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... production process for the manufacture of low density polyethylene in which a reaction pressure of about 15... terephthalate) (PET) manufacture using dimethyl terephthalate means the manufacturing of poly(ethylene.... Poly(ethylene terephthalate) (PET) manufacture using terephthalic acid means the manufacturing of poly...

RF plasma cleaning of silicon substrates with high-density polyethylene contamination

NASA Astrophysics Data System (ADS)

Cagomoc, Charisse Marie D.; De Leon, Mark Jeffry D.; Ebuen, Anna Sophia M.; Gilos, Marlo Nicole R.; Vasquez, Magdaleno R., Jr.

2018-01-01

Upon contact with a polymeric material, microparticles from the polymer may adhere to a silicon (Si) substrate during device processing. The adhesion contaminates the surface and, in turn, leads to defects in the fabricated Si-based microelectronic devices. In this study, Si substrates with artificially induced high-density polyethylene (HDPE) contamination was exposed to 13.56 MHz radio frequency (RF) plasma utilizing argon and oxygen gas admixtures at a power density of 5.6 W/cm2 and a working pressure of 110 Pa for up to 6 min of treatment. Optical microscopy studies revealed the removal of up to 74% of the polymer contamination upon plasma exposure. Surface free energy (SFE) increased owing to the removal of contaminants as well as the formation of polar groups on the Si surface after plasma treatment. Atomic force microscopy scans showed a decrease in surface roughness from 12.25 nm for contaminated samples to 0.77 nm after plasma cleaning. The smoothening effect can be attributed to the removal of HDPE particles from the surface. In addition, scanning electron microscope images showed that there was a decrease in the amount of HDPE contaminants adhering onto the surface after plasma exposure.

Establishing a design procedure for buried steel-reinforced high-density polyethylene pipes : a field study.

DOT National Transportation Integrated Search

2015-11-01

Two field tests were conducted to investigate the field performance of steel-reinforced high-density polyethylene : (SRHDPE) pipes during installation and under traffic loading. One test site was located on E 1000 road in Lawrence, KS, which is : clo...

Detecting strain in birefringent materials using spectral polarimetry

NASA Technical Reports Server (NTRS)

Garner, Harold R. (Inventor); Ragucci, Anthony J. (Inventor); Cisar, Alan J. (Inventor); Huebschman, Michael L. (Inventor)

2010-01-01

A method, computer program product and system for analyzing multispectral images from a plurality of regions of birefringent material, such as a polymer film, using polarized light and a corresponding polar analyzer to identify differential strain in the birefringent material. For example, the birefringement material may be low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinylidene chloride, polyester, nylon, or cellophane film. Optionally, the method includes generating a real-time quantitative strain map.

Demonstration and Validation of a Regenerated Cellulose Dialysis Membrane Diffusion Sampler for Monitoring Ground Water Quality and Remediation Progress at DoD Sites for Perchlorate and Explosives Compounds

DTIC Science & Technology

2010-09-01

Regulatory Council LRL Laboratory reporting level LDPE Low-density polyethylene MDL Minimum detection limit MNA Monitored natural attenuation...consists of a tubular-shaped bag made of flexible low-density polyethylene ( LDPE ) (Vroblesky, 2001a, 2001b). The LDPE tube is heat-sealed on one end...be constructed from small- diameter LDPE tubing that fits into small-diameter wells. These polyethylene diffusion bag (PDB) samplers have been

Demonstration and Validation of a Regenerated Cellulose Dialysis Membrane Diffusion Sampler for Monitoring Ground-Water Quality and Remediation Progress at DoD Site: Perchlorate and Ordnance Compounds

DTIC Science & Technology

2011-10-01

Regulatory Council LDPE low-density polyethylene MDL minimum detection limit NAVFAC ESC Naval Facilities Engineering Command Engineering Service...membrane sampler design consists of a tubular-shaped bag made of flexible low-density polyethylene ( LDPE ) (Vroblesky, 2001a, 2001b). The LDPE tube is...requirements, and can be constructed from small-diameter LDPE tubing that fits into small- 4 diameter wells. These polyethylene diffusion bag

Influence of different factors on the destruction of films based on polylactic acid and oxidized polyethylene

NASA Astrophysics Data System (ADS)

Podzorova, M. V.; Tertyshnaya, Yu. V.; Pantyukhov, P. V.; Shibryaeva, L. S.; Popov, A. A.; Nikolaeva, S.

2016-11-01

Influence of different environmental factors on the degradation of film samples based on polylactic acid and low density polyethylene with the addition of oxidized polyethylene was studied in this work. Different methods were used to find the relationship between degradation and ultraviolet, moisture, oxygen. It was found that the addition of oxidized polyethylene, used as a model of recycled polyethylene, promotes the degradation of blends.

Catalytic and thermal depolymerization of low value post-consumer high density polyethylene plastic

USDA-ARS?s Scientific Manuscript database

The feasibility of catalytic and non-catalytic pyrolytic conversion of low value post-consumer high density polyethylene (HDPE) plastic into crude oil and subsequent distillation was explored. Translation of optimized conditions for catalytic and non-catalytic pyrolysis from TGA to a bench-scale sys...

Evaluation of cotton byproducts as fillers for poly(lactic acid) and low density polyethylene

USDA-ARS?s Scientific Manuscript database

Polymeric composites based on cotton burr and cottonseed bull have been prepared by melt blending and extrusion. For poly(lactic acid) (PLA) and low-density polyethylene (LDPE), addition of the fillers only slightly changed the composite’s thermal properties and significantly decreased the composite...

Quantification of micro stickies

Treesearch

Mahendra Doshi; Jeffrey Dyer; Salman Aziz; Kristine Jackson; Said M. Abubakr

1997-01-01

The objective of this project was to compare the different methods for the quantification of micro stickies. The hydrophobic materials investigated in this project for the collection of micro stickies were Microfoam* (polypropylene packing material), low density polyethylene film (LDPE), high density polyethylene (HDPE; a flat piece from a square plastic bottle), paper...

Improvement of mechanical and thermal properties of high energy electron beam irradiated HDPE/hydroxyapatite nano-composite

NASA Astrophysics Data System (ADS)

Mohammadi, M.; Ziaie, F.; Majdabadi, A.; Akhavan, A.; Shafaei, M.

2017-01-01

In this research work, the nano-composites of high density polyethylene/hydroxyapatite samples were manufactured via two methods: In the first method, the granules of high density polyethylene and nano-structure hydroxyapatite were processed in an internal mixer to prepare the nano-composite samples with a different weight percentage of the reinforcement phase. As for the second one, high density polyethylene was prepared in nano-powder form in boiling xylene. During this procedure, the hydroxyapatite nano-powder was added with different weight percentages to the solvent to obtain the nano-composite. In both of the procedures, the used hydroxyapatite nano-powder was synthesized via hydrolysis methods. The samples were irradiated under 10 MeV electron beam in 70-200 kGy of doses. Mechanical, thermal and morphological properties of the samples were investigated and compared. The results demonstrate that the nano-composites which we have prepared using nano-polyethylene, show better mechanical and thermal properties than the composites prepared from normal polyethylene granules, due to the better dispersion of nano-particles in the polymer matrix.

Improvements in processing characteristics and engineering properties of wood flour-filled high density polyethylene composite sheeting in the presence of hollow glass microspheres

Treesearch

Baris Yalcin; Steve E Amos; Andrew S D Souza; Craig M Clemons; I Sedat Gunes; Troy K Ista

2012-01-01

Hollow glass microspheres were introduced into wood flour/high density polyethylene composites by melt compounding in a twin-screw extruder. The prepared composites were subsequently converted to extruded profiles in order to obtain composite sheeting. The presence of hollow glass microspheres highly reduced the density of the extruded sheets down to 0.9 g/cc, while...

Effect of packaging materials on shelf life and quality of banana cultivars (Musa spp.).

PubMed

Hailu, M; Seyoum Workneh, T; Belew, D

2014-11-01

This study was carried out to evaluate the effect of packaging materials on the shelf life of three banana cultivars. Four packaging materials, namely, perforated low density polyethylene bag, perforated high density polyethylene bag, dried banana leaf, teff straw and no packaging materials (control) were used with three banana cultivars, locally known as, Poyo, Giant Cavendish and Williams I. The experiment was carried out in Randomized Complete Block Design in a factorial combination with three replications. Physical parameters including weight loss, peel colour, peel thickness, pulp thickness, pulp to peel ratio, pulp firmness, pulp dry matter, decay, loss percent of marketability were assessed every 3 days. Banana remained marketable for 36 days in the high density polyethylene and low density polyethylene bags, and for 18 days in banana leaf and teff straw packaging treatments. Unpackaged fruits remained marketable for 15 days only. Fruits that were not packaged lost their weight by 24.0 % whereas fruits packaged in banana leaf and teff straw became unmarketable with final weight loss of 19.8 % and 20.9 %, respectively. Packaged fruits remained well until 36th days of storage with final weight loss of only 8.2 % and 9.20 %, respectively. Starting from green mature stage, the colour of the banana peel changed to yellow and this process was found to be fast for unpackaged fruits. Packaging maintained the peel and the pulp thickness, firmness, dry matter and pulp to peel ratio was kept lower. Decay loss for unpackaged banana fruits was16 % at the end of date 15, whereas the decay loss of fruits packaged using high density and low density polyethylene bags were 43.0 % and 41.2 %, respectively at the end of the 36th day of the experiment. It can, thus, be concluded that packaging of banana fruits in high density and low density polyethylene bags resulted in longer shelf life and improved quality of the produce followed by packaging in dried banana leaf and teff straw.

Demonstration and Validation of a Regenerated Cellulose Dialysis Membrane Diffusion Sampler for Monitoring Ground Water Quality and Remediation Progress at DoD Sites

DTIC Science & Technology

2007-08-30

ITRC Interstate Technology Regulatory Council LRL Laboratory reporting level LDPE Low-density polyethylene MDL Minimum detection limit MNA...diameter of the well. Another diffusion membrane sampler design consists of a tubular-shaped bag made of flexible low-density polyethylene ( LDPE ...

Mechanical properties of high density polyethylene--pennycress press cake composites

USDA-ARS?s Scientific Manuscript database

Pennycress press cake (PPC) is evaluated as a bio-based fiber reinforcement. PPC is a by-product of crop seed oil extraction. Composites with a high density polyethylene (HDPE) matrix are created by twin screw compounding of 25% by weight of PPC and either 0% or 5% by weight of maleated polyethyle...

Landfill Liners and Covers: Properties and Application to Army Landfills.

DTIC Science & Technology

1984-06-01

polymers, TPE can be seamed by heat techniques. Materials such as thermoplastic EPDM and nitrile rubber /PVC blends are still being tested to determine their...such as polyethylene (PE), polyvinyl chloride (PVC), butyl rubber , ethylene propylene diene monomer ( EPDM ), chlorinated polyethylene (CPE), and others...chlorosulfonated polyethy- lene (CSPE), chlorinated polyethylene (CPE), butyl rubber , ethylene propylene S rubber ( EPDM ), neoprene, high-density polyethylene

Effect of polyethylene glycol conjugation on conformational and colloidal stability of a monoclonal antibody antigen-binding fragment (Fab').

PubMed

Roque, Cristopher; Sheung, Anthony; Rahman, Nausheen; Ausar, S Fernando

2015-02-02

We have investigated the effects of site specific "hinge" polyethylene glycol conjugation (PEGylation) on thermal, pH, and colloidal stability of a monoclonal antibody antigen-binding fragment (Fab') using a variety of biophysical techniques. The results obtained by circular dichroism (CD), ultraviolet (UV) absorbance, and fluorescence spectroscopy suggested that the physical stability of the Fab' is maximized at pH 6-7 with no apparent differences due to PEGylation. Temperature-induced aggregation experiments revealed that PEGylation was able to increase the transition temperature, as well as prevent the formation of visible and subvisible aggregates. Statistical comparison of the three-index empirical phase diagram (EPD) revealed significant differences in thermal and pH stability signatures between Fab' and PEG-Fab'. Upon mechanical stress, micro-flow imaging (MFI) and measurement of the optical density at 360 nm showed that the PEG-Fab' had significantly higher resistance to surface-induced aggregation compared to the Fab'. Analysis of the interaction parameter, kD, indicated repulsive intermolecular forces for PEG-Fab' and attractive forces for Fab'. In conclusion, PEGylation appears to protect Fab' against thermal and mechanical stress-induced aggregation, likely due to a steric hindrance mechanism.

Effects of Interphase Modification and Biaxial Orientation on Dielectric Properties of Poly(ethylene terephthalate)/Poly(vinylidene fluoride-co-hexafluoropropylene) Multilayer Films.

PubMed

Yin, Kezhen; Zhou, Zheng; Schuele, Donald E; Wolak, Mason; Zhu, Lei; Baer, Eric

2016-06-01

Recently, poly(vinylidene fluoride) (PVDF)-based multilayer films have demonstrated enhanced dielectric properties, combining high energy density and high dielectric breakdown strength from the component polymers. In this work, further enhanced dielectric properties were achieved through interface/interphase modulation and biaxial orientation for the poly(ethylene terephthalate)/poly(methyl methacrylate)/poly(vinylidene fluoride-co-hexafluoropropylene) [PET/PMMA/P(VDF-HFP)] three-component multilayer films. Because PMMA is miscible with P(VDF-HFP) and compatible with PET, the interfacial adhesion between PET and P(VDF-HFP) layers should be improved. Biaxial stretching of the as-extruded multilayer films induced formation of highly oriented fibrillar crystals in both P(VDF-HFP) and PET, resulting in improved dielectric properties with respect to the unstretched films. First, the parallel orientation of PVDF crystals reduced the dielectric loss from the αc relaxation in α crystals. Second, biaxial stretching constrained the amorphous phase in P(VDF-HFP) and thus the migrational loss from impurity ions was reduced. Third, biaxial stretching induced a significant amount of rigid amorphous phase in PET, further enhancing the breakdown strength of multilayer films. Due to the synergistic effects of improved interfacial adhesion and biaxial orientation, the PET/PMMA/P(VDF-HFP) 65-layer films with 8 vol % PMMA exhibited optimal dielectric properties with an energy density of 17.4 J/cm(3) at breakdown and the lowest dielectric loss. These three-component multilayer films are promising for future high-energy-density film capacitor applications.

Impact fracture toughness evaluation for high-density polyethylene materials

NASA Astrophysics Data System (ADS)

Cherief, M. N. D.; Elmeguenni, M.; Benguediab, M.

2017-03-01

The impact fracture behavior of a high-density polyethylene (HDPE) material is investigated experimentally and theoretically. Single-edge notched bending (SENB) specimens are tested in experiments with three-point bending and in the Charpy impact tests. An energy model is proposed for evaluating the HDPE impact toughness, which provides a description of both brittle and ductile fracture.

Effect of weathering variables on the lightness of high-density polyethylene woodflour composites

Treesearch

Nicole M. Stark

2005-01-01

Wood-plastic lumber is promoted as a low-maintenance, high-durability product. After weathering, however, wood-plastic composites (WPCs) often fade. In the first part of this study, 50 percent woodflour-filled high- density polyethylene (HDPE) composite samples were manufactured. Composites were exposed to two accelerated weathering cycles in a xenon- arc type...

Grafting of molecularly imprinted polymer to porous polyethylene filtration membranes by plasma polymerization.

PubMed

Cowieson, D; Piletska, E; Moczko, E; Piletsky, S

2013-08-01

An application of plasma-induced grafting of polyethylene membranes with a thin layer of molecularly imprinted polymer (MIP) was presented. High-density polyethylene (HDPE) membranes, "Vyon," were used as a substrate for plasma grafting modification. The herbicide atrazine, one of the most popular targets of the molecular imprinting, was chosen as a template. The parameters of the plasma treatment were optimized in order to achieve a good balance between polymerization and ablation processes. Modified HDPE membranes were characterized, and the presence of the grafted polymeric layer was confirmed based on the observed weight gain, pore size measurements, and infrared spectrometry. Since there was no significant change in the porosity of the modified membranes, it was assumed that only a thin layer of the polymer was introduced on the surface. The experiments on the re-binding of the template atrazine to the membranes modified with MIP and blank polymers were performed. HDPE membranes which were grafted with polymer using continuous plasma polymerization demonstrated the best result which was expressed in an imprinted factor equal to 3, suggesting that molecular imprinting was successfully achieved.

Biodegradation of low-density polyethylene by marine bacteria from pelagic waters, Arabian Sea, India.

PubMed

Harshvardhan, Kumar; Jha, Bhavanath

2013-12-15

Sixty marine bacteria isolated from pelagic waters were screened for their ability to degrade low-density polyethylene; among them, three were positive and able to grow in a medium containing polythene as the sole carbon source. The positive isolates were identified as Kocuria palustris M16, Bacillus pumilus M27 and Bacillus subtilis H1584 based on the 16S rRNA gene sequence homology. The weight loss of polyethylene was 1%, 1.5% and 1.75% after 30 days of incubation with the M16, M27 and H1584 isolates, respectively. The maximum (32%) cell surface hydrophobicity was observed in M16, followed by the H1584 and M27 isolates. The viability of the isolates growing on the polyethylene surface was confirmed using a triphenyltetrazolium chloride reduction test. The viability was also correlated with a concomitant increase in the protein density of the biomass. Polyethylene biodegradation was further confirmed by an increase in the Keto Carbonyl Bond Index, the Ester Carbonyl Bond Index and the Vinyl Bond Index, which were calculated from FT-IR spectra. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mechanical and electrical properties of low density polyethylene filled with carbon nanotubes

NASA Astrophysics Data System (ADS)

Sabet, Maziyar; Soleimani, Hassan

2014-08-01

Carbon nanotubes (CNTs) reveal outstanding electrical and mechanical properties in addition to nanometer scale diameter and high aspect ratio, consequently, making it an ideal reinforcing agent for high strength polymer composites. Low density polyethylene (LDPE)/CNT composites were prepared via melt compounding. Mechanical and electrical properties of (LDPE)/CNT composites with different CNT contents were studied in this research.

21 CFR 178.3130 - Antistatic and/or anti-fogging agents in food-packaging materials.

Code of Federal Regulations, 2010 CFR

2010-04-01

... antistatic agent at levels not to exceed 0.2 percent by weight in molded or extruded high-density polyethylene (having a density ≥0.95 g/cm3 and polypropylene containers that contact food only of the types... levels not to exceed 0.15 pct by weight in molded or extruded polyethylene containers that contact food...

New plastic recycling technology | Science Inventory | US EPA

EPA Pesticide Factsheets

Greater than 60% of the total plastic content of municipal solid waste is comprised of polyolefins (high-density, low-density, and linear polyethylene and polypropylene. Polyethylene (PE) is the largest-volume component but presents a challenge due to the absence of low-energy degradation processes. This news column provides a digest of recent technical reports relating to clean technology and environmental policy,

Thermal and catalytic degradation of high and low density polyethylene into fuel oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uddin, Azhar; Koizumi, Kazuo; Sakata, Yusaku

1996-12-31

The degradation of four different types of polyethylene (PE) namely high density PE (HDPE), low density PE (LDPE), linear low density PE (LLDPE), and cross-linked PE (XLPE) was carried out at 430 {degrees}C by batch operation using silica-alumina as a solid acid catalyst and thermally without any catalyst. For thermal degradation, both HDPE and XLPE produced significant amount of wax-like compounds and the yield of liquid products were lower than that of LDPE and LLDPE. LDPE and LLDPE also produced small amount of wax-like compounds. Thus the structure of the degrading polymers influenced the product yields. The liquid products frommore » thermal degradation were broadly distributed in the carbon fraction of n-C{sub 5} to n-C{sub 25} (boiling point range, 36-405 C). With silica-alumina, the polyethylenes were converted to liquid products with high yields (77-83 wt%) and without any wax production. The liquid products were distributed in the range of n-C{sub 5} to n-C{sub 20} (Mostly C{sub 5}-C{sub 12}). Solid acid catalyst indiscriminately degraded the various types of polyethylene into light fuel oil. 5 refs., 4 figs., 1 tab.« less

Study on ternary low density polyethylene/linear low density polyethylene/thermoplastic starch blend films.

PubMed

Sabetzadeh, Maryam; Bagheri, Rouhollah; Masoomi, Mahmood

2015-03-30

In this work, low-density polyethylene/linear low-density polyethylene/thermoplastic starch (LDPE/LLDPE/TPS) films are prepared with the aim of obtaining environmentally friendly materials containing high TPS content with required packaging properties. Blending of LDPE/LLDPE (70/30 wt/wt) with 5-20 wt% of TPS and 3 wt% of PE-grafted maleic anhydride (PE-g-MA) is performed in a twin-screw extruder, followed by the blowing process. Differential scanning calorimetric results indicate starch has more pronounced effect on crystallization of LLDPE than LDPE. Scanning electron micrograph shows a fairly good dispersion of TPS in PE matrices. Fourier transfer infrared spectra confirm compatibility between polymers using PE-g-MA as the compatibilizer. Storage modulus, loss modulus and complex viscosity increase with incorporation of starch. Tensile strength and elongation-at-break decrease from 18 to 10.5 MPa and 340 to 200%, respectively when TPS increases from 5 to 20%. However, the required mechanical properties for packaging applications are attained when 15 wt% starch is added, as specified in ASTM D4635. Finally 12% increase in water uptake is achieved with inclusion of 15 wt% starch. Copyright © 2014 Elsevier Ltd. All rights reserved.

21 CFR 177.1610 - Polyethylene, chlorinated.

Code of Federal Regulations, 2014 CFR

2014-04-01

... chlorination of polyethylene conforming to the density, maximum n-hexane extractable fraction, and maximum..._federal_regulations/ibr_locations.html.), and has a 7.0 percent maximum extractable fraction in n-hexane...

Biodegradation of thermally treated low density polyethylene by fungus Rhizopus oryzae NS 5.

PubMed

Awasthi, Shraddha; Srivastava, Neha; Singh, Tripti; Tiwary, D; Mishra, Pradeep Kumar

2017-05-01

Polythene is considered as one of the important object used in daily life. Being versatile in nature and resistant to microbial attack, they effectively cause environmental pollution. In the present study, biodegradation of low-density polyethylene (LDPE) have been performed using fungal lab isolate Rhizopus oryzae NS5. Lab isolate fungal strain capable of adhering to LDPE surface was used for the biodegradation of LDPE. This strain was identified as Rhizopus oryzae NS5 (Accession No. KT160362). Fungal growth was observed on the surface of the polyethylene when cultured in potato dextrose broth at 30 °C and 120 rpm, for 1 month. LDPE film was characterized before and after incubation by Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy and universal tensile machine. About 8.4 ± 3% decrease (gravimetrically) in weight and 60% reduction in tensile strength of polyethylene was observed. Scanning electron microscope analysis showed hyphal penetration and degradation on the surface of polyethylene. Atomic force microscope analysis showed increased surface roughness after treatment with fungal isolate. A thick network of fungal hyphae forming a biofilm was also observed on the surface of the polyethylene pieces. Present study shows the potential of Rhizopus oryzae NS5 in polyethylene degradation in eco friendly and sustainable manner.

Biodegradable materials containing recycled polymers

NASA Astrophysics Data System (ADS)

Podzorova, M. V.; Tertyshnaya, Yu V.; Popov, A. A.

2018-04-01

The work is devoted to study the effects of different environmental factors such as water, oxygen and, light composition based on polylactide and polyethylene of low density with the addition of oxidized polyethylene, as an analog of recycled materials. Established that in the composition polylactide – polyethylene at the first stage the significant impact of moisture and UV light. The influence of UV radiation on polylactide destruction was proved by differential scanning calorimetry (DSC). It is found that polylactic acid is oxidized slower than polyethylene.

Preparation and tensile properties of linear low density polyethylene/rambutan peels (Nephelium chryseum Blum.) flour blends

NASA Astrophysics Data System (ADS)

Nadhirah, A. Ainatun.; Sam, S. T.; Noriman, N. Z.; Voon, C. H.; Samera, S. S.

2015-05-01

The effect of rambutan peels flour (RPF) content on the tensile properties of linear low density polyethylene filled with rambutan peel flour was studied. RPF was melt blended with linear low-density polyethylene (LLDPE). LLDPE/RPF blends were prepared by using internal mixer (brabender) at 160 °C with the flour content ranged from 0 to 15 wt%. The tensile properties were tested by using a universal testing machine (UTM) according to ASTM D638. The highest tensile strength was observed for pure LLDPE while the tensile strength LLDPE/RPF decreased gradually with the addition of rambutan peels flour content from 0% to 15%. Young's modulus of 63 µm to 250 µm rambutan peels blends with LLDPE with the fiber loading of 0 - 15 wt% increased with increasing fiber loading.

A complete life cycle assessment of high density polyethylene plastic bottle

NASA Astrophysics Data System (ADS)

Treenate, P.; Limphitakphong, N.; Chavalparit, O.

2017-07-01

This study was aimed to determine environmental performances of a lubricant oil bottle made from high density polyethylene and to develop potential measures for reducing its impacts. A complete life cycle assessment was carried out to understand a whole effect on the environment from acquiring, processing, using, and disposing the product. Two scenarios of disposal phase; recycle and incineration: were examined to quantify a lesser degree on environmental impact. The results illustrated that major impacts of the two scenarios were at the same categories with the highest contributor of raw material acquisition and pre-processing. However, all impacts in case of recycling provided a lower point than that in case of incineration, except mineral extraction. Finally, feasible measures for reducing the environmental impact of high density polyethylene plastic bottle were proposed in accordance with 3Rs concept.

TECHNICAL GUIDANCE DOCUMENT: THE FABRICATION OF POLYETHYLENE FML FIELD SEAMS

EPA Science Inventory

This technical guidance document is meant to augment the numerous construction quality control and construction assurance (CQC and CQA) guidelines that are presently available for high density polyethylene (HDPE) liner installation and inspection.

Time–temperature superposition principle applied to a kenaf-fiber/high-density polyethylene composite

Treesearch

Mehdi Tajvidi; Robert H. Falk; John C. Hermanson

2005-01-01

The time–temperature superposition principle was applied to the viscoelastic properties of a kenaf- fiber/high-density polyethylene (HDPE) composite, and its validity was tested. With a composite of 50% kenaf fibers, 48% HDPE, and 2% compatibilizer, frequency scans from a dynamic mechanical analyzer were performed in the range of 0.1–10 Hz at five different...

Polyam/Polycoat Certification Program

DTIC Science & Technology

2010-06-01

Wound for Mortar Cartridges and Hand Grenades." Material Specifications Polylam material: 40 lb Natural Kraft/14 lb low density polyethylene ( LDPE )/70...established requirements. Testing shows that they have been producing polylam 70 lb Natural Kraft/28 lb low density polyethylene ( LDPE )/40 lb Natural...Kraft; doubling the amount of LDPE from the specified 14 lb paper weight. Furthermore, they have been producing the polycoat at 70 lb Natural Kraft/29 lb

Effect of low-density polyethylene on smoke emissions from burning of simulated debris piles

Treesearch

Seyedehsan Hosseini; Qi Li; Manish Shrivastava; David R. Weise; David R. Cocker; J. Wayne Miller; Heejung S Jung

2014-01-01

Low-density polyethylene (LDPE) plastic is used to keep piled debris from silvicultural activities—activities associated with development and care of forests—dry to enable efficient disposal by burning. The effects of inclusion of LDPE in this manner on smoke emissions are not well known. In a combustion laboratory experiment, 2-kg mixtures of LDPE and manzanita (

Effect of stearic acid-grafted starch compatibilizer on properties of linear low density polyethylene/thermoplastic starch blown film.

PubMed

Khanoonkon, Nattaporn; Yoksan, Rangrong; Ogale, Amod A

2016-02-10

The present work aims to investigate the effect of stearic acid-grafted starch (ST-SA) on the rheological, thermal, optical, dynamic mechanical thermal, and tensile properties of linear low density polyethylene/thermoplastic starch (LLDPE/TPS) blends, as well as on their water vapor and oxygen barrier properties. Blends consisting of LLDPE and TPS in a weight ratio of 60:40 and ST-SA at different concentrations, i.e. 1, 3 and 5%, were prepared using a twin-screw extruder. The obtained resins were subsequently converted into films via blown film extrusion. Incorporation of ST-SA resulted in a decreased degree of shear thinning, reduced ambient temperature elasticity, and improved tensile strength, secant modulus, extensibility, and UV absorption, as well as diminished water vapor and oxygen permeabilities of the LLDPE/TPS blend. These effects are attributed to the enhanced interfacial adhesion between LLDPE and TPS phases through the compatibilizing effect induced by ST-SA, and the good dispersion of the TPS phase in the LLDPE matrix. The results confirmed that ST-SA could potentially be used as a compatibilizer for the LLDPE/TPS blend system. Copyright © 2015 Elsevier Ltd. All rights reserved.

21 CFR 177.1610 - Polyethylene, chlorinated.

Code of Federal Regulations, 2010 CFR

2010-04-01

... produced by the direct chlorination of polyethylene conforming to the density, maximum n-hexane extractable... extractable fraction in n-hexane at 50 °C, as determined by the method described in § 177.1520(d)(3)(ii). (b...

21 CFR 177.1610 - Polyethylene, chlorinated.

Code of Federal Regulations, 2011 CFR

2011-04-01

... produced by the direct chlorination of polyethylene conforming to the density, maximum n-hexane extractable... extractable fraction in n-hexane at 50 °C, as determined by the method described in § 177.1520(d)(3)(ii). (b...

21 CFR 177.1610 - Polyethylene, chlorinated.

Code of Federal Regulations, 2012 CFR

2012-04-01

... produced by the direct chlorination of polyethylene conforming to the density, maximum n-hexane extractable... extractable fraction in n-hexane at 50 °C, as determined by the method described in § 177.1520(d)(3)(ii). (b...

21 CFR 177.1610 - Polyethylene, chlorinated.

Code of Federal Regulations, 2013 CFR

2013-04-01

... produced by the direct chlorination of polyethylene conforming to the density, maximum n-hexane extractable... extractable fraction in n-hexane at 50 °C, as determined by the method described in § 177.1520(d)(3)(ii). (b...

40 CFR 264.314 - Special requirements for bulk and containerized liquids.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Inorganic minerals, other inorganic materials, and elemental carbon (e.g., aluminosilicates, clays... (ii) High molecular weight synthetic polymers (e.g., polyethylene, high density polyethylene (HDPE), polypropylene, polystyrene, polyurethane, polyacrylate, polynorborene, polyisobutylene, ground synthetic rubber...

Nanostructure and thermal properties of melt compounded PE/clay nanocomposites filled with an organosilylated montmorillonite

NASA Astrophysics Data System (ADS)

Scarfato, Paola; Incarnato, Loredana; Di Maio, Luciano; Dittrich, Bettina; Niebergall, Ute; Böhning, Martin; Schartel, Bernhard

2015-12-01

In this work we report on the functionalization of a natural sodium montmorillonite (MMT) with (3-glycidyloxypropyl)trimethoxysilane by a silylation procedure and on its use as nanofiller in melt compounding of polyethylene nanocomposites. The obtained organosilylated clay showed higher interlayer spacing than the original MMT and higher thermal stability with respect to most of commercial organoclays modified with alkylammonium salts. Its addition (at 5wt%) to two different polyethylene matrices (a low density polyethylene, LDPE, and a high density polyethylene, HDPE), processed in a pilot-scale twin-screw extruder, allowed to produce hybrids with nanoscale dispersion of the filler, as demonstrated by X-ray diffraction. Thermogravimetric and differential scanning thermal analyses point out that the obtained nanocomposites do not show noticeable changes in the thermal behavior of both LDPE and HDPE, even if a slight reduction in the overall bulk crystallinity was observed in presence of the nanofillers.

Extrudable polymer-polymer composites based on ultra-high molecular weight polyethylene

NASA Astrophysics Data System (ADS)

Panin, S. V.; Kornienko, L. A.; Alexenko, V. O.; Buslovich, D. G.; Dontsov, Yu. V.

2017-12-01

Mechanical and tribotechnical characteristics of polymer-polymeric composites of UHMWPE are studied with the aim of developing extrudable, wear-resistant, self-lubricant polymer mixtures for Additive Manufacturing (AM). The motivation of the study is their further application as feedstocks for 3D printing. Blends of UHMWPE with graft- and block copolymers of low-density polyethylene (HDPE-g-VTMS, HDPE-g-SMA, HDPE-b-EVA), polypropylene (PP), block copolymers of polypropylene and polyamide with linear low density polyethylene (PP-b-LLDPE, PA-b-LLDPE), as well as cross-linked polyethylene (PEX-b), are examined. The choice of compatible polymer components for an ultra- high molecular weight matrix for increasing processability (extrudability) is motivated by the search for commercially available and efficient additives aimed at developing wear-resistant extrudable polymer composites for additive manufacturing. The extrudability, mechanical properties and wear resistance of UHMWPE-based polymer-polymeric composites under sliding friction with different velocities and loads are studied.

Dynamic mechanical analysis of compatibilizer effect on the mechanical properties of wood flour/high-density polyethylene composites

Treesearch

Mehdi Behzad; Medhi Tajvidi; Ghanbar Ehrahimi; Robert H. Falk

2004-01-01

In this study, effect of MAPE (maleic anhydride polyethylene) as the compatibilizer on the mechanical properties of wood-flour polyethylene composites has been investigated by using Dynamic Mechanical Analysis (DMA). Composites were made at 25% and 50% by weight fiber contents and 1% and 2% compatibilizer respectively. Controls were also made at the same fiber contents...

Measurement of the loss tangent of low-density polyethylene with a nanoindentation technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loubet, J. L.; Oliver, W. C.; Lucas, B. N.

2000-05-01

This paper describes experimental measurements of the linear viscoelastic behavior of the surface of low-density (LD) polyethylene in contact with a pyramidal Berkovich diamond indenter. The experiments were carried out at two different temperatures, 15.9 and 27.2 degree sign C, between frequencies of 0.1 and 800 Hz. Using the shift of the loss tangent between the two temperatures at frequencies lower than 20 Hz and an Arrhenius equation, an activation energy of 105{+-}2 kJ/mol was obtained. This value is in good agreement with the bulk value of the {alpha} relaxation of LD polyethylene reported in the literature. (c) 2000 Materialsmore » Research Society.« less

The yield and post-yield behavior of high-density polyethylene

NASA Technical Reports Server (NTRS)

Semeliss, M. A.; Wong, R.; Tuttle, M. E.

1990-01-01

An experimental and analytical evaluation was made of the yield and post-yield behavior of high-density polyethylene, a semi-crystalline thermoplastic. Polyethylene was selected for study because it is very inexpensive and readily available in the form of thin-walled tubes. Thin-walled tubular specimens were subjected to axial loads and internal pressures, such that the specimens were subjected to a known biaxial loading. A constant octahederal shear stress rate was imposed during all tests. The measured yield and post-yield behavior was compared with predictions based on both isotropic and anisotropic models. Of particular interest was whether inelastic behavior was sensitive to the hydrostatic stress level. The major achievements and conclusions reached are discussed.

Caracterisation dielectrique de nanocomposites LLDPE/nano-glaises: Fidelite des techniques et proprietes electriques

NASA Astrophysics Data System (ADS)

Daran-Daneau, Cyril

In order to answer the energetic needs of the future, insulation, which is the central piece of high voltage equipment, has to be reinvented. Nanodielectrics seem to be the promise of a mayor technological breakthrough. Based on nanocomposites with a linear low density polyethylene matrix reinforced by nano-clays and manufactured from a commercial master batch, the present thesis aims to characterise the accuracy of measurement techniques applied on nanodielectrics and also the dielectric properties of these materials. Thus, dielectric spectroscopy accuracy both in frequency and time domain is analysed with a specific emphasis on the impact of gold sputtering of the samples and on the measurements transposition from time domain to frequency domain. Also, when measuring dielectric strength, the significant role of surrounding medium and sample thickness on the variation of the alpha scale factor is shown and analysed in relation with the presence of surface partial discharges. Taking into account these limits and for different nanoparticles composition, complex permittivity as a function of frequency, linearity and conductivity as a function of applied electric field is studied with respect to the role that seems to play nanometrics interfaces. Similarly, dielectric strength variation as a function of nano-clays content is investigated with respect to the partial discharge resistance improvement that seems be induced by nanoparticle addition. Finally, an opening towards nanostructuration of underground cables' insulation is proposed considering on one hand the dielectric characterisation of polyethylene matrix reinforced by nano-clays or nano-silica nanodielectrics and on the other hand a succinct cost analysis. Keywords: nanodielectric, linear low density polyethylene, nanoclays, dielectric spectroscopy, dielectric breakdown

Biodegradation of polyethylene by the thermophilic bacterium Brevibacillus borstelensis.

PubMed

Hadad, D; Geresh, S; Sivan, A

2005-01-01

To select a polyethylene-degrading micro-organism and to study the factors affecting its biodegrading activity. A thermophilic bacterium Brevibaccillus borstelensis strain 707 (isolated from soil) utilized branched low-density polyethylene as the sole carbon source and degraded it. Incubation of polyethylene with B. borstelensis (30 days, 50 degrees C) reduced its gravimetric and molecular weights by 11 and 30% respectively. Brevibaccillus borstelensis also degraded polyethylene in the presence of mannitol. Biodegradation of u.v. photo-oxidized polyethylene increased with increasing irradiation time. Fourier Transform Infra-Red (FTIR) analysis of photo-oxidized polyethylene revealed a reduction in carbonyl groups after incubation with the bacteria. This study demonstrates that polyethylene--considered to be inert--can be biodegraded if the right microbial strain is isolated. Enrichment culture methods were effective for isolating a thermophilic bacterium capable of utilizing polyethylene as the sole carbon and energy source. Maximal biodegradation was obtained in combination with photo-oxidation, which showed that carbonyl residues formed by photo-oxidation play a role in biodegradation. Brevibaccillus borstelensis also degraded the CH2 backbone of nonirradiated polyethylene. Biodegradation of polyethylene by a single bacterial strain contributes to our understanding of the process and the factors affecting polyethylene biodegradation.

Structural Composite Construction Materials Manufactured from Municipal Solid Waste

DTIC Science & Technology

1994-04-20

in Table 1. Candidate matrix materials included polystyrene (PS) or expanded polystyrene (EPS), high density polyethylene (HDPE), and polyethylene...companies make a variety of expanded polystyrene insulation panels that arc used in insulation and roofing systems.46 Thermoplastics are seeing

Electromigration and Deposition of Micro-Scale Calcium Carbonate Structures with Controlled Morphology and Polymorphism

DTIC Science & Technology

2013-04-01

precipitation of calcium carbonate in structured templates including microporous polycarbonate membranes and polyethylene foams. Para- meters...polyethylene foam). Microporous polycarbonate membranes and Medium-Density PolyEthylene (MDPE) foam specimens were used as the porous organic...voids in hardened concrete. DOI:10.1520/C624-06. West Conshohocken, PA: ASTM International . www.astm.org. Bersa, L., and M. Liu. 2007. A review on

Melting, crystallization and storage stability of virgin coconut oil and its blends by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR).

PubMed

Srivastava, Yashi; Semwal, Anil Dutt; Sajeevkumar, Vallayil Appukuttan; Sharma, G K

2017-01-01

The blends were prepared of virgin coconut oil with refined soyabean oil (VCO-RSOY) and refined safflower oil (VCO-RSAFF). Blending with VCO improved the fatty acid composition which increased the shelf stability of 20:80 VCO-RSOY and VCO-RSAFF up to 12 months in different packaging systems such as low density polyethylene, linear low density polyethylene, metalized polyester pouches, polyethylene teteraphthalate, high density polyethylene (HDPE), Amber HDPE bottle. The specific spectral regions of FTIR proved to be very useful for the determination of adulteration as well as for the study of oxidation process. Band shifts observed at 3008, 1652, 1397, 1097, 912 and 845 cm -1 have been used to differentiate RSAFF from VCO. VCO spectrums did not have these chemical shifts. Further the spectrum of RSOY showed same band shifts as RSAFF except 1652, 1397, 869.6 and 845 cm -1 . Differential Scanning Calorimetry provided useful information regarding the nature of thermodynamic changes related to physical state of vegetable oil. The physical state changes included melting and crystallization events which require the intake and release of energy.

Optimization of Cold Spray Deposition of High-Density Polyethylene Powders

NASA Astrophysics Data System (ADS)

Bush, Trenton B.; Khalkhali, Zahra; Champagne, Victor; Schmidt, David P.; Rothstein, Jonathan P.

2017-10-01

When a solid, ductile particle impacts a substrate at sufficient velocity, the resulting heat, pressure and plastic deformation can produce bonding between the particle and the substrate. The use of a cool supersonic gas flow to accelerate these solid particles is known as cold spray deposition. The cold spray process has been commercialized for some metallic materials, but further research is required to unlock the exciting potential material properties possible with polymeric particles. In this work, a combined computational and experimental study was employed to study the cold spray deposition of high-density polyethylene powders over a wide range of particle temperatures and impact velocities. Cold spray deposition of polyethylene powders was demonstrated across a range broad range of substrate materials including several different polymer substrates with different moduli, glass and aluminum. A material-dependent window of successful deposition was determined for each substrate as a function of particle temperature and impact velocity. Additionally, a study of deposition efficiency revealed the optimal process parameters for high-density polyethylene powder deposition which yielded a deposition efficiency close to 10% and provided insights into the physical mechanics responsible for bonding while highlighting paths toward future process improvements.

Polyethylene Ear Reconstruction: A State-of-the-Art Surgical Journey.

PubMed

Reinisch, John; Tahiri, Youssef

2018-02-01

The use of a porous high-density polyethylene implant for ear reconstruction is gradually gaining acceptance because it allows for a pleasing ear reconstruction in young children before they enter school. In response to this growing interest, the authors decided to write an article clarifying in detail all the steps of this challenging procedure. In this article, the authors also answer all the common questions that surgeons have when they come to observe the operation, or when they go back to their respective practices and start performing this procedure. The authors describe in detail the operative steps that allow for a successful ear reconstruction using porous high-density polyethylene. The key parts of this operation are to meticulously harvest a well-vascularized superficial temporoparietal fascia flap and to use appropriate color-matched skin grafts. This method allows for a pleasing ear reconstruction with excellent definition, projection, symmetry, and long-term viability. The use of porous high-density polyethylene with a thin superficial temporoparietal fascia flap coverage is the authors' preferred method of ear reconstruction because it can be performed at an earlier age, in a single stage, as an outpatient procedure, and with minimal discomfort and psychological trauma for the patients and parents.

The influence of pre-conditioning on space charge formation in LDPE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, R.J.; Henriksen, M.; Holboell, J.T.

1996-12-31

In this paper the authors present space charge accumulation data for planar low density polyethylene samples subjected to 20kV/mm dc fields at room temperature. The data were obtained using the laser-induced-pressure-pulse (LIPP) technique. Some of the samples were conditioned by holding them at 40 C in short-circuit at rotary pump pressure for 48hr prior to measurement. Such conditioning had no consistent effect on the space charge. The extent of charge injection/extraction at the semicon electrodes appeared to vary considerably between samples.

Studying Thermally Induced Chemical and Physical Transformations in Common Synthetic Polymers: A Laboratory Project

NASA Astrophysics Data System (ADS)

Hodgson, Steven C.; Orbell, John D.; Bigger, Stephen W.; Scheirs, John

2000-06-01

A simple project is described for introducing students to some experimental procedures commonly used to measure the effects of thermal treatment on synthetic polymers. The thermally induced changes that occur in the commodity polymers low-density polyethylene (LDPE), poly(ethylene terephthalate) (PET), and poly(vinyl chloride) (PVC) are examined as a function of the time of thermal treatment in an air-circulating oven. In particular, simple procedures are described for determining (i) the polymer hydroperoxide (POOH) content and carbonyl index (CI) of LDPE, (ii) the extent of whitening of PET, and (iii) the extent of discoloration or "yellowing" of PVC, all of which change during thermal treatment. The POOH content of LDPE is determined using a ferrometric method and the CI of this polymer is measured by both Fourier transform infrared spectroscopy and a staining technique involving 2,4-dinitrophenylhydrazine. The thermal oxidation of LDPE and the kinetics of formation of its POOH and carbonyl species are discussed with reference to the accepted mechanism for the autooxidation of polyolefins. The whitening of PET and the yellowing of PVC during thermal treatment are explained by means of a crystallization process and a "zip" dehydrochlorination reaction, respectively.

Comparison of degradation effects induced by gamma radiation and electron beam radiation in two cable jacketing materials

NASA Astrophysics Data System (ADS)

Bartoníček, B.; Plaček, V.; Hnát, V.

2007-05-01

The radiation degradation behavior of commercial low density polyethylene (LDPE) and ethylene-vinylacetate (EVA) cable materials has been investigated. The changes of mechanical properties, thermooxidative stability and density exhibit different radiation stability towards 60Co-gamma radiation and 160 keV electron beam radiation. This difference reflects much higher penetration of the gamma radiation through the polymeric material as a function of sample thickness. These results are discussed with respect to the role of beta radiation during design basis events in a nuclear power plants. In case when total accidental design basis event (DBE) dose (involving about 80% soft beta radiation) is simulated by 60Co-gamma radiation the conservatism is reached.

Effect of nanoclay on the properties of low density polyethylene/linear low density polyethylene/thermoplastic starch blend films.

PubMed

Sabetzadeh, Maryam; Bagheri, Rouhollah; Masoomi, Mahmood

2016-05-05

The aim of this work is to study effect of nanoclay (Cloisite(®)15A) on morphology and properties of low-density polyethylene/linear low-density polyethylene/thermoplastic starch (LDPE/LLDPE/TPS) blend films. LDPE/LLDPE blend (70/30wt/wt) containing 15wt.% TPS in the presence of PE-grafted maleic anhydride (PE-g-MA, 3wt.%) with 1, 3 and 5phr of nanoclay are compounded in a twin-screw extruder and then film blown using a blowing machine. Nanocomposites with intercalated structures are obtained, based on the X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. However, some exfoliated single platelets in the samples are also observable. Scanning electron microscopic (SEM) images confirm the ability of both exfoliated nanoclay and PE-g-MA to reduce the size of TPS domains and deform their particles within the PE matrices. As the nanoclay content increases from 1 to 5phr, the tensile strength, tear resistance and impact strength of the films increase, whereas a slight decrease in the elongation at break is observed. The film samples with 5phr nanoclay possess the required packaging properties, as specified by ASTM D4635. These films provide desired optical transparency and surface roughness which are more attractive for packaging applications. Copyright © 2016. Published by Elsevier Ltd.

Regulating the surface poly(ethylene glycol) density of polymeric nanoparticles and evaluating its role in drug delivery in vivo.

PubMed

Du, Xiao-Jiao; Wang, Ji-Long; Liu, Wei-Wei; Yang, Jin-Xian; Sun, Chun-Yang; Sun, Rong; Li, Hong-Jun; Shen, Song; Luo, Ying-Li; Ye, Xiao-Dong; Zhu, Yan-Hua; Yang, Xian-Zhu; Wang, Jun

2015-11-01

Poly(ethylene glycol) (PEG) is usually used to protect nanoparticles from rapid clearance in blood. The effects are highly dependent on the surface PEG density of nanoparticles. However, there lacks a detailed and informative study in PEG density and in vivo drug delivery due to the critical techniques to precisely control the surface PEG density when maintaining other nano-properties. Here, we regulated the polymeric nanoparticles' size and surface PEG density by incorporating poly(ε-caprolactone) (PCL) homopolymer into poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) and adjusting the mass ratio of PCL to PEG-PCL during the nanoparticles preparation. We further developed a library of polymeric nanoparticles with different but controllable sizes and surface PEG densities by changing the molecular weight of the PCL block in PEG-PCL and tuning the molar ratio of repeating units of PCL (CL) to that of PEG (EG). We thus obtained a group of nanoparticles with variable surface PEG densities but with other nano-properties identical, and investigated the effects of surface PEG densities on the biological behaviors of nanoparticles in mice. We found that, high surface PEG density made the nanoparticles resistant to absorption of serum protein and uptake by macrophages, leading to a greater accumulation of nanoparticles in tumor tissue, which recuperated the defects of decreased internalization by tumor cells, resulting in superior antitumor efficacy when carrying docetaxel. Copyright © 2015 Elsevier Ltd. All rights reserved.

Catalytic thermal cracking of post-consumer waste plastics to fuels: Part 1 - Kinetics and optimization

USDA-ARS?s Scientific Manuscript database

Thermogravimetric analysis (TGA) was used to investigate thermal and catalytic pyrolysis of waste plastics such as prescription bottles (polypropylene/PP), high density polyethylene, landfill liners (polyethylene/PE), packing materials (polystyrene/PS), and foams (polyurethane/PU) into crude plastic...

Demonstration and Validation of a Regenerated Cellulose Dialysis Membrane Diffusion Sampler for Monitoring Ground-Water Quality and Remediation Progress at DoD Sites

DTIC Science & Technology

2010-04-01

LDPE low-density polyethylene LF low-flow purging LRL laboratory reporting level MDL minimum detection limit MNA monitored natural attenuation...shaped bag made of flexible low-density polyethylene ( LDPE ) (Vroblesky, 2001a, 2001b). The LDPE tube is heat-sealed on one end, filled with high...from small- diameter LDPE tubing that fits into small-diameter wells. These PDB samplers have been shown to be useful only for collection of VOCs

Solving a product safety problem using a recycled high density polyethylene container

NASA Technical Reports Server (NTRS)

Liu, Ping; Waskom, T. L.

1993-01-01

The objectives are to introduce basic problem-solving techniques for product safety including problem identification, definition, solution criteria, test process and design, and data analysis. The students are given a recycled milk jug made of high density polyethylene (HDPE) by blow molding. The objectives are to design and perform proper material test(s) so they can evaluate the product safety if the milk jug is used in a certain way which is specified in the description of the procedure for this investigation.

Nanostructure and thermal properties of melt compounded PE/clay nanocomposites filled with an organosilylated montmorillonite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarfato, Paola, E-mail: pscarfato@unisa.it; BAM - Federal Institute for Materials Research and Testing, 7.5 Technical Properties of Polymeric Materials, Unter den Eichen 87 - 12205 Berlin; Incarnato, Loredana

In this work we report on the functionalization of a natural sodium montmorillonite (MMT) with (3-glycidyloxypropyl)trimethoxysilane by a silylation procedure and on its use as nanofiller in melt compounding of polyethylene nanocomposites. The obtained organosilylated clay showed higher interlayer spacing than the original MMT and higher thermal stability with respect to most of commercial organoclays modified with alkylammonium salts. Its addition (at 5wt%) to two different polyethylene matrices (a low density polyethylene, LDPE, and a high density polyethylene, HDPE), processed in a pilot-scale twin-screw extruder, allowed to produce hybrids with nanoscale dispersion of the filler, as demonstrated by X-ray diffraction.more » Thermogravimetric and differential scanning thermal analyses point out that the obtained nanocomposites do not show noticeable changes in the thermal behavior of both LDPE and HDPE, even if a slight reduction in the overall bulk crystallinity was observed in presence of the nanofillers.« less

Evaluation of Paulownia elongata wood polyethylene composites

USDA-ARS?s Scientific Manuscript database

Paulownia wood flour (PWF), a byproduct of milling lumber, was employed as a bio-filler and blended with high density polyethylene (HDPE) via extrusion. Paulownia wood (PW) shavings were milled through a 1-mm screen then separated via shaking into various particle fractions using sieves (#30 - < #2...

Preparation and Properties of a Novel Microcrystalline Cellulose-Filled Composites Based on Polyamide 6/High-Density Polyethylene

PubMed Central

Xu, Shihua; Yi, Shunmin; He, Jun; Wang, Haigang; Fang, Yiqun; Wang, Qingwen

2017-01-01

In the present study, lithium chloride (LiCl) was utilized as a modifier to reduce the melting point of polyamide 6 (PA6), and then 15 wt % microcrystalline cellulose (MCC) was compounded with low melting point PA6/high-density polyethylene (HDPE) by hot pressing. Crystallization analysis revealed that as little as 3 wt % LiCl transformed the crystallographic forms of PA6 from semi-crystalline to an amorphous state (melting point: 220 °C to none), which sharply reduced the processing temperature of the composites. LiCl improved the mechanical properties of the composites, as evidenced by the fact that the impact strength of the composites was increased by 90%. HDPE increased the impact strength of PA6/MCC composites. In addition, morphological analysis revealed that incorporation of LiCl and maleic anhydride grafted high-density polyethylene (MAPE) improved the interfacial adhesion. LiCl increased the glass transition temperature of the composites (the maximum is 72.6 °C). PMID:28773169

Molecular and Kinetic Models for High-rate Thermal Degradation of Polyethylene

DOE PAGES

Lane, J. Matthew; Moore, Nathan W.

2018-02-01

Thermal degradation of polyethylene is studied under the extremely high rate temperature ramps expected in laser-driven and X-ray ablation experiments—from 10 10 to 10 14 K/s in isochoric, condensed phases. The molecular evolution and macroscopic state variables are extracted as a function of density from reactive molecular dynamics simulations using the ReaxFF potential. The enthalpy, dissociation onset temperature, bond evolution, and observed cross-linking are shown to be rate dependent. These results are used to parametrize a kinetic rate model for the decomposition and coalescence of hydrocarbons as a function of temperature, temperature ramp rate, and density. In conclusion, the resultsmore » are contrasted to first-order random-scission macrokinetic models often assumed for pyrolysis of linear polyethylene under ambient conditions.« less

Study of the Auger line shape of polyethylene and diamond

NASA Technical Reports Server (NTRS)

Dayan, M.; Pepper, S. V.

1984-01-01

The KVV Auger electron line shapes of carbon in polyethylene and diamond have been studied. The spectra were obtained in derivative form by electron beam excitation. They were treated by background subtraction, integration and deconvolution to produce the intrinsic Auger line shape. Electron energy loss spectra provided the response function in the deconvolution procedure. The line shape from polyethylene is compared with spectra from linear alkanes and with a previous spectrum of Kelber et al. Both spectra are compared with the self-convolution of their full valence band densities of states and of their p-projected densities. The experimental spectra could not be understood in terms of existing theories. This is so even when correlation effects are qualitatively taken into account account to the theories of Cini and Sawatzky and Lenselink.

Molecular and Kinetic Models for High-rate Thermal Degradation of Polyethylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lane, J. Matthew; Moore, Nathan W.

Thermal degradation of polyethylene is studied under the extremely high rate temperature ramps expected in laser-driven and X-ray ablation experiments—from 10 10 to 10 14 K/s in isochoric, condensed phases. The molecular evolution and macroscopic state variables are extracted as a function of density from reactive molecular dynamics simulations using the ReaxFF potential. The enthalpy, dissociation onset temperature, bond evolution, and observed cross-linking are shown to be rate dependent. These results are used to parametrize a kinetic rate model for the decomposition and coalescence of hydrocarbons as a function of temperature, temperature ramp rate, and density. In conclusion, the resultsmore » are contrasted to first-order random-scission macrokinetic models often assumed for pyrolysis of linear polyethylene under ambient conditions.« less

Elasticity and photoelasticity relationships for polyethylene terephthalate fiber networks by molecular simulation

NASA Astrophysics Data System (ADS)

Nayak, Kapileswar; Das, Sushanta; Nanavati, Hemant

2008-01-01

We present a framework for the development of elasticity and photoelasticity relationships for polyethylene terephthalate fiber networks, incorporating aspects of the primary molecular structure. Semicrystalline polymeric fiber networks are modeled as sequentially arranged crystalline and amorphous regions. Rotational isomeric states-Monte Carlo simulations of amorphous chains of up to 360 bonds (degree of polymerization, DP =60), confined between and bridging infinite impenetrable crystalline walls, have been characterized by Ω, the probability density of the intercrystal separation h, and Δβ, the polarizability anisotropy. lnΩ and Δβ have been modeled as functions of h, yielding the chain deformation relationships. The development has been extended to the fiber network to yield the photoelasticity relationships. We execute our framework by fitting to experimental stress-elongation data and employing the single fitted parameter to directly predict the birefringence-elongation behavior, without any further fitting. Incorporating the effect of strain-induced crystallization into the framework makes it physically more meaningful and yields accurate predictions of the birefringence-elongation behavior.

Influence of ordering change on the optical and thermal properties of inflation polyethylene films

NASA Astrophysics Data System (ADS)

Morikawa, Junko; Orie, Akihiro; Hikima, Yuta; Hashimoto, Toshimasa; Juodkazis, Saulius

2011-04-01

Changes of thermal diffusivity inside femtosecond laser-structured volumes as small as few percent were reliably determined (with standard deviation less than 1%) with miniaturized sensors. An increase of thermal diffusivity of a crystalline high-density polyethylene (HDPE) inflation films by 10-20% from the measured (1.16 ± 0.01) × 10 -7 m 2 s -1 value in regions not structured by femtosecond laser pulses is considerably larger than that of non-crystalline polymers, 0-3%. The origin of the change of thermal diffusivity are interplay between the laser induced disordering, voids' formation, compaction, and changes in molecular orientation. It is shown that laser structuring can be used to modify thermal and optical properties. The birefringence and infrared spectroscopy with thermal imaging of CH 2 vibrations are confirming inter-relation between structural, optical, and thermal properties of the laser-structured crystalline HDPE inflation films. Birefringence modulation as high as Δ n ˜ ± 1 × 10 -3 is achieved with grating structures.

Morphology and crystalline-phase-dependent electrical insulating properties in tailored polypropylene for HVDC cables

NASA Astrophysics Data System (ADS)

Zha, Jun-Wei; Yan, Hong-Da; Li, Wei-Kang; Dang, Zhi-Min

2016-11-01

Polypropylene (PP) has become one promising material to potentially replace the cross-link polyethylene used for high voltage direct current cables. Besides the isotactic polypropylene, the block polypropylene (b-PP) and random polypropylene (r-PP) can be synthesized through the copolymerization of ethylene and propylene molecules. In this letter, the effect of morphology and crystalline phases on the insulating electrical properties of PP was investigated. It was found that the introduction of polyethylene monomer resulted in the formation of β and γ phases in b-PP and r-PP. The results from the characteristic trap energy levels indicated that the β and γ phases could induce deep electron traps which enable to capture the carriers. And the space charge accumulation was obviously suppressed. Besides, the decreased electrical conductivity was observed in b-PP and r-PP. It is attributed to the existence of deep traps which can effectively reduce the carrier mobility and density in materials.

Preparation and properties of banana fiber-reinforced composites based on high density polyethylene (HDPE)/Nylon-6 blends.

PubMed

Liu, H; Wu, Q; Zhang, Q

2009-12-01

Banana fiber (BaF)-filled composites based on high density polyethylene (HDPE)/Nylon-6 blends were prepared via a two-step extrusion method. Maleic anhydride grafted styrene/ethylene-butylene/styrene triblock polymer (SEBS-g-MA) and maleic anhydride grafted polyethylene (PE-g-MA) were used to enhance impact performance and interfacial bonding between BaF and the resins. Mechanical, crystallization/melting, thermal stability, water absorption, and morphological properties of the composites were investigated. In the presence of SEBS-g-MA, better strengths and moduli were found for HDPE/Nylon-6 based composites compared with corresponding HDPE based composites. At a fixed weight ratio of PE-g-MA to BaF, an increase of BaF loading up to 48.2 wt.% led to a continuous improvement in moduli and flexural strength of final composites, while impact toughness was lowered gradually. Predicted tensile modulus by the Hones-Paul model for three-dimensional random fiber orientation agreed well with experimental data at the BaF loading of 29.3 wt.%. However, the randomly-oriented fiber models underestimated experimental data at higher fiber levels. It was found that the presence of SEBS-g-MA had a positive influence on reinforcing effect of the Nylon-6 component in the composites. Thermal analysis results showed that fractionated crystallization of the Nylon-6 component in the composites was induced by the addition of both SEBS-g-MA and PE-g-MA. Thermal stability of both composite systems differed slightly, except an additional decomposition peak related to the minor Nylon-6 for the composites from the HDPE/Nylon-6 blends. In the presence of SEBS-g-MA, the addition of Nylon-6 and increased BaF loading level led to an increase in the water absorption value of the composites.

Biodegradation of thermoplastic starch and its blends with poly(lactic acid) and polyethylene: influence of morphology

USDA-ARS?s Scientific Manuscript database

The room temperature mineralization of thermoplastic starch (TPS) with a high glycerol content and its blends with low-density polyethylene (LDPE) and polylactic acid (PLA) are examined under controlled degradation conditions. These results are correlated with the morphologies and continuity behavio...

Use of cotton gin trash and compatibilizers in polyethylene composites

USDA-ARS?s Scientific Manuscript database

The ginning of cotton produces 15-42% of foreign materials, called “cotton gin trash”, including cotton burr, stems, leaf fragment, and dirt. In this work we examined the mechanical properties of composites of low density polyethylene (LDPE) and cotton burr. The burr was ground into powder, and se...

Preparation and properties of recycled HDPE/clay hybrids

Treesearch

Yong Lei; Qinglin Wu; Craig M. Clemons

2007-01-01

Hybrids based on recycled high density polyethylene (RHDPE) and organic clay were made by melt compounding. The influence of blending method, compatibilizers, and clay content on clay intercalation and exfoliation, RHDPE crystallization behavior, and the mechanical properties of RHDPE/clay hybrids were investigated. Both maleated polyethylene (MAPE) and titanate could...

Interrelation of electret properties of polyethylene foam from the method of cross-linking

NASA Astrophysics Data System (ADS)

Gilmanov, I. R.; Galikhanov, M. F.; Gilmanova, A. R.

2017-09-01

The electret properties of chemically cross-linked polyethylene foam and physically cross-linked polyethylene foam have been studied. It has been shown that chemically cross-linked polyethylene foam has higher surface potential, effective surface charge density and electric field strength compared to physically bonded polyethylene foam. This is due to the presence of molecules and fragments of dicumyl peroxide, which can play the role of traps for injection charge carriers, a greater degree of cross-linking and with the oxidation of polyethylene, which occurs during irradiation during physical cross-linking. When the foam is deformed, its electret properties are reduced, and when the volume is relaxed, they are restored. This is due to the partial mutual compensation of homo- and heterocharge during compression and the return of the structure of the gas-filled polymer to its former position when the load is removed.

Demonstration and Validation of a Regenerated Cellulose Dialysis Membrane Diffusion Sampler for Monitoring Ground Water Quality and Remediation Progress at DoD Sites for Perchlorate and Explosives Compounds (ER-0313)

DTIC Science & Technology

2010-09-30

Inductively coupled plasma – mass spectrometry ITRC Interstate Technology Regulatory Council LRL Laboratory reporting level LDPE Low-density polyethylene...diameter of the well. Another diffusion membrane sampler design consists of a tubular-shaped bag made of flexible low-density polyethylene ( LDPE ...Vroblesky, 2001a, 2001b). The LDPE tube is heat-sealed on one end, filled with high-purity water, heat-sealed at the top, and then suspended in a well to

Methodology for Long-Term Permeation Test Periods for HD in High-Density Polyethylene: Universal Munitions Storage Container for the Non-Stockpile Chemical Materiel Program

DTIC Science & Technology

2016-05-01

measurements for distilled mustard (HD) and non- welded high-density polyethylene (HDPE) at 120 °F were completed for thicknesses of 20–80 mil for...extrapolation to the ~250 mil container thickness. A Fick’s law extrapolation inferred a breakthrough time of 10–11 days for the 250 mil non- welded HDPE at...8 3.2 Permeation Results for 20 mil HDPE at 100 °F: Welded ................................10 3.2.1 Confirmation Test: Welded

Microbial degradation of low-density polyethylene (LDPE) by Aspergillus clavatus strain JASK1 isolated from landfill soil.

PubMed

Gajendiran, Anudurga; Krishnamoorthy, Sharmila; Abraham, Jayanthi

2016-06-01

Polythene and plastic waste are found to accumulate in the environment, posing a major ecological threat. They are found to be considered non-degradable, once it enters the environment it has been found to remain there indefinitely. However, significant attention has been placed on biodegradable polymer, identification of microbes with degradative potential on plastic material. The aim of the present investigation was to biodegrade low-density polyethylene (LDPE) using potential fungi isolated from landfill soil. Based on 18S rRNA analyses the isolated strain was identified as Aspergillus clavatus. LDPE degradation by A. clavatus was monitored for 90 days of incubation in aqueous medium. The degradation was confirmed by changes in polyethylene weight, CO 2 evolution by Strum test, infrared spectra and morphological changes by SEM and AFM analysis.

Radicals mediated magnetism in Ar plasma treated high-density polyethylene

NASA Astrophysics Data System (ADS)

Orendáč, M.; Čižmár, E.; Kažiková, V.; Orendáčová, A.; Řezníčková, A.; Kolská, Z.; Švorčík, V.

2018-05-01

Electron-spin resonance of high-density polyethylene treated by Ar plasma at 300 K was performed in X-band at temperatures from 2.1 K to 290 K. The observed spectra suggest presence of allyl radicals, whereas the central peak may be attributed to polyenyl radicals or dangled bonds. Pronounced narrowing of the resonance line observed above glassy temperature of polyethylene may be ascribed to thermally activated motional effect with the activation energy Ea /kB = 160 K. The absence of strong exchange interactions is suggested by negligible exchange narrowing found at 2.1 K. The suggestion is supported by the analysis of the temperature dependence of the intensity at low temperatures, which is explicable assuming the coexistence of non-interacting radicals and S = 1/2 dimers with a distribution of antiferromagnetic couplings varying from 2 K to nominally 25 K.

Fabrication of Tunable Submicro- or Nano-structured Polyethylene Materials form Immiscible Blends with Cellulose Acetate Butyrate

USDA-ARS?s Scientific Manuscript database

Low density polyethylene (LDPE) was prepared into micro- or submicro-spheres or nanofibers via melt blending or extrusion of cellulose acetate butyrate (CAB)/LDPE immiscible blends and subsequent removal of the CAB matrix. The sizes of the PE spheres or fibers can be successfully controlled by varyi...

Delaying microbial proliferation in freshly peeled shallots by active packaging incorporating ethanol vapour-controlled release sachets and low storage temperature.

PubMed

Utto, Weerawate; Preutikul, Rittirong; Malila, Patcharee; Noomhorm, Athapol; Bronlund, John E

2018-03-01

This research was conducted to investigate effects of ethanol vapour released in active packaging and storage temperatures on the quality of freshly peeled shallots. The package tested was a solid polypropylene tray incorporating an ethanol vapour-controlled release sachet. The sachet was made of an aluminium foil film on one side and either low-density polyethylene or nylon/polyethylene on the other. Individual sachets contained silica gel adsorbent as the carrier pre-loaded with ethanol. One sachet was placed in each tray containing the peeled shallots and the tray was heat sealed with the low-density polyethylene film lid. Packages were stored at either 10 or 25 ℃ for 10 d. Trays containing only peeled shallots were designated as controls. High storage temperature stimulated quality changes in the shallots. Although ethanol vapour accumulated in the active package headspace, the extent to which ethanol concentrations increased within the shallots was not significantly different from that in the control packages. Microbial proliferation in terms of yeast and mould counts could be delayed through a combination of 10 ℃ and ethanol vapour released from the low-density polyethylene sachet. The ethanol vapour accumulated in the packages did not have a significant effect on mass loss, firmness, and colour changes in the peeled shallots, or on the concentrations of oxygen and carbon dioxide in the packages.

Enhancement of the Mechanical Properties of Basalt Fiber-Wood-Plastic Composites via Maleic Anhydride Grafted High-Density Polyethylene (MAPE) Addition.

PubMed

Chen, Jinxiang; Wang, Yong; Gu, Chenglong; Liu, Jianxun; Liu, Yufu; Li, Min; Lu, Yun

2013-06-18

This study investigated the mechanisms, using microscopy and strength testing approaches, by which the addition of maleic anhydride grafted high-density polyethylene (MAPE) enhances the mechanical properties of basalt fiber-wood-plastic composites (BF-WPCs). The maximum values of the specific tensile and flexural strengths are achieved at a MAPE content of 5%-8%. The elongation increases rapidly at first and then continues slowly. The nearly complete integration of the wood fiber with the high-density polyethylene upon MAPE addition to WPC is examined, and two models of interfacial behavior are proposed. We examined the physical significance of both interfacial models and their ability to accurately describe the effects of MAPE addition. The mechanism of formation of the Model I interface and the integrated matrix is outlined based on the chemical reactions that may occur between the various components as a result of hydrogen bond formation or based on the principle of compatibility, resulting from similar polarity. The Model I fracture occurred on the outer surface of the interfacial layer, visually demonstrating the compatibilization effect of MAPE addition.

Application of a constant hole volume Sanchez-Lacombe equation of state to mixtures relevant to polymeric foaming.

PubMed

von Konigslow, Kier; Park, Chul B; Thompson, Russell B

2018-06-06

A variant of the Sanchez-Lacombe equation of state is applied to several polymers, blowing agents, and saturated mixtures of interest to the polymer foaming industry. These are low-density polyethylene-carbon dioxide and polylactide-carbon dioxide saturated mixtures as well as polystyrene-carbon dioxide-dimethyl ether and polystyrene-carbon dioxide-nitrogen ternary saturated mixtures. Good agreement is achieved between theoretically predicted and experimentally determined solubilities, both for binary and ternary mixtures. Acceptable agreement with swelling ratios is found with no free parameters. Up-to-date pure component Sanchez-Lacombe characteristic parameters are provided for carbon dioxide, dimethyl ether, low-density polyethylene, nitrogen, polylactide, linear and branched polypropylene, and polystyrene. Pure fluid low-density polyethylene and nitrogen parameters exhibit more moderate success while still providing acceptable quantitative estimations. Mixture estimations are found to have more moderate success where pure components are not as well represented. The Sanchez-Lacombe equation of state is found to correctly predict the anomalous reversal of solubility temperature dependence for low critical point fluids through the observation of this behaviour in polystyrene nitrogen mixtures.

Profiles in garbage: Polyethylene terephthalate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, C.

1997-11-01

Polyethylene terephthalate (PET) is a plastic resin used primarily to make bottles. Soft drinks -- along with salad dressing, fruit juices, peanut butter, and other household and consumer products -- use PET bottles. PET also is used for film, sheeting for cups and food trays, oven-safe trays, and other uses. PET is a relatively new packaging resin, first commercialized in the early 1970s. Because it is an ``engineered`` resin, PET is more expensive than commodity resins such as high-density polyethylene (HDPE) and, for the same reason, it is usually the highest valued plastic recyclable.

Mechanical degradation temperature of waste storage materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fink, M.C.; Meyer, M.L.

1993-05-13

Heat loading analysis of the Solid Waste Disposal Facility (SWDF) waste storage configurations show the containers may exceed 90{degrees}C without any radioactive decay heat contribution. Contamination containment is primarily controlled in TRU waste packaging by using multiple bag layers of polyvinyl chloride and polyethylene. Since literature values indicate that these thermoplastic materials can begin mechanical degradation at 66{degrees}C, there was concern that the containment layers could be breached by heating. To better define the mechanical degradation temperature limits for the materials, a series of heating tests were conducted over a fifteen and thirty minute time interval. Samples of a low-densitymore » polyethylene (LDPE) bag, a high-density polyethylene (HDPE) high efficiency particulate air filter (HEPA) container, PVC bag and sealing tape were heated in a convection oven to temperatures ranging from 90 to 185{degrees}C. The following temperature limits are recommended for each of the tested materials: (1) low-density polyethylene -- 110{degrees}C; (2) polyvinyl chloride -- 130{degrees}C; (3) high-density polyethylene -- 140{degrees}C; (4) sealing tape -- 140{degrees}C. Testing with LDPE and PVC at temperatures ranging from 110 to 130{degrees}C for 60 and 120 minutes also showed no observable differences between the samples exposed at 15 and 30 minute intervals. Although these observed temperature limits differ from the literature values, the trend of HDPE having a higher temperature than LDPE is consistent with the reference literature. Experimental observations indicate that the HDPE softens at elevated temperatures, but will retain its shape upon cooling. In SWDF storage practices, this might indicate some distortion of the waste container, but catastrophic failure of the liner due to elevated temperatures (<185{degrees}C) is not anticipated.« less

Three-Dimensional Nanometer Features of Direct Current Electrical Trees in Low-Density Polyethylene.

PubMed

Pallon, Love K H; Nilsson, Fritjof; Yu, Shun; Liu, Dongming; Diaz, Ana; Holler, Mirko; Chen, Xiangrong R; Gubanski, Stanislaw; Hedenqvist, Mikael S; Olsson, Richard T; Gedde, Ulf W

2017-03-08

Electrical trees are one reason for the breakdown of insulating materials in electrical power systems. An understanding of the growth of electrical trees plays a crucial role in the development of reliable high voltage direct current (HVDC) power grid systems with transmission voltages up to 1 MV. A section that contained an electrical tree in low-density polyethylene (LDPE) has been visualized in three dimensions (3D) with a resolution of 92 nm by X-ray ptychographic tomography. The 3D imaging revealed prechannel-formations with a lower density with the width of a couple of hundred nanometers formed around the main branch of the electrical tree. The prechannel structures were partially connected with the main tree via paths through material with a lower density, proving that the tree had grown in a step-by-step manner via the prestep structures formed in front of the main channels. All the prechannel structures had a size well below the limit of the Paschen law and were thus not formed by partial discharges. Instead, it is suggested that the prechannel structures were formed by electro-mechanical stress and impact ionization, where the former was confirmed by simulations to be a potential explanation with electro-mechanical stress tensors being almost of the same order of magnitude as the short-term modulus of low-density polyethylene.

Laboratory tests on fungal resistance of wood filled polyethylene composites

Treesearch

Craig M. Clemons; Rebecca E. Ibach

2002-01-01

A standard method for determining the durability of structural wood was modified for testing the fungal resistance of composites made from high density polyethylene filled with 50% wood flour. Moisture content, mechanical properties, and weight loss were measured over 12 weeks exposure to brown-and white-rot fungi. Mechanical properties were decreased, but irreversible...

Products of Chemistry: Alkanes: Abundant, Pervasive, Important, and Essential.

ERIC Educational Resources Information Center

Seymour, Raymond B.

1989-01-01

Discusses the history and commercialization of alkanes. Examines the nomenclature and uses of alkanes. Studies polymerization and several types of polyethylenes: low-density, high-density, low-molecular-weight, cross-linked, linear low-density, and ultrahigh-molecular-weight. Includes a glossary of hydrocarbon terms. (MVL)

Effect of Aspergillus versicolor strain JASS1 on low density polyethylene degradation

NASA Astrophysics Data System (ADS)

Gajendiran, A.; Subramani, S.; Abraham, J.

2017-11-01

Low density polyethylene (LDPE) waste disposal remains one of the major environmental concerns faced by the world today. In past decades, major focus has been given to enhance the biodegradation of LDPE by microbial species. In this present study, Aspergillus versicolor with the ability to degrade LDPE was isolated from municipal landfill area using enrichment technique. Based on 18S rRNA gene sequencing confirmed its identity as Aspergillus versicolor. The biodegradation study was carried out for 90 d in M1 medium. The degradation behaviour of LDPE films by Aspergillus versicolor strain JASS1 were confirmed by weight loss, CO2 evolution, Scanning electron microscopy (SEM) analysis, Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) technique. From current investigation, it can be concluded that our isolated strain JASS1 had the potential to degrade LDPE films and it can be useful in solving the problem caused by polyethylene in the environment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali Sinag; Melike Sungur; Mustafa Gullu

This study describes the detailed hydrocarbon type characterization of the tar (liquid phase) obtained by copyrolysis of Mustafa Kemal Paa (M.K.P.) lignite (Turkey) and low density polyethylene (LDPE) and by pyrolysis of coal and LDPE individually. Various spectroscopic techniques (gas chromatography-mass spectroscopy (GC-MS), nuclear magnetic resonance spectroscopy ({sup 1}H NMR), Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC)) are used for characterization, and the effect of the experimental conditions (temperature, lignite:low density polyethylene (LDPE) ratio, and catalyst) on the hydrocarbon distributions is discussed. The results show that the tars obtained by copyrolysis have similar properties with commercial gasolinemore » (especially in the presence of Red mud). Red mud and bentonite used as catalysts make a positive effect on the production of olefins instead aromatics. Polyethylene acts as a hydrogenation medium for the coal product as revealed by FTIR results. 18 refs., 9 figs., 5 tabs.« less

Influence of adipic acid on tensile and morphology properties of linear low density polyethylene/rambutan peels flour blends

NASA Astrophysics Data System (ADS)

Nadhirah, A. A.; Sam, S. T.; Noriman, N. Z.; Ragunathan, S.; Ismail, H.

2015-07-01

This study investigate about the tensile and morphological properties of degradable polymer produced from linear low density polyethylene/rambutan peel flour (LLDPE/RPF) blends and adipic acid (AA) was used as a compatibilizer by varying the rambutan peel flour (RPF) amount from 0-25wt%. The samples were subjected to tensile and morphological tests. AA compatibilized showed higher strength compared to uncompatibilized blends. The Young's modulus for LLDPE/RPF blends increased with increasing flour content. However, the addition of adipic acid had reduced the Young's Modulus.

Quantifying VOC emissions from polymers: A case study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schulze, J.K.; Qasem, J.S.; Snoddy, R.

1996-12-31

Evaluating residual volatile organic compound emissions emanating from low-density polyethylene can pose significant challenges. These challenges include quantifying emissions from: (a) multiple process lines with different operating conditions; (b) several different comonomers; (c) variations of comonomer content in each grade; and (d) over 120 grades of LDPE. This presentation is a Case Study outlining a project to develop grade-specific emission data for low-density polyethylene pellets. This study included extensive laboratory analyses and required the development of a relational database to compile analytical results, calculate the mean concentration and standard deviation, and generate emissions reports.

Icephobicity and the effect of water condensation on the superhydrophobic low-density polyethylene surface

NASA Astrophysics Data System (ADS)

Yuan, Zhiqing; Wang, Menglei; Huang, Juan; Wang, Xian; Bin, Jiping; Peng, Chaoyi; Xing, Suli; Xiao, Jiayu; Zeng, Jingcheng; Xiao, Ximei; Fu, Xin; Gong, Huifang; Zhao, Dejian; Chen, Hong

2015-06-01

A superhydrophobic surface was obtained on a low-density polyethylene (LDPE) substrate using a facile method. The water contact angle and the sliding angle of the superhydrophobic LDPE surface were 155 ± 2° and 4°, respectively. The ice shear stress of the superhydrophobic LDPE surface was 2.08 times smaller than that of the flat LDPE surface. The superhydrophobic surface still showed excellent icephobicity and superhydrophobicity after undergoing a circulatory icing/deicing procedure five times. In addition, water condensation and its effect on the icephobicity of the as-prepared superhydrophobic surface were also studied.

Degradation of lindane and hexachlorobenzene in supercritical carbon dioxide using palladium nanoparticles stabilized in microcellular high-density polyethylene.

PubMed

Wu, Bei-Zen; Chen, GuanYu; Yak, HwaKwang; Liao, Weisheng; Chiu, KongHwa; Peng, Shie-Ming

2016-06-01

Palladium nanoparticles stabilized in microcellular high-density polyethylene prepared through supercritical foaming, supercritical impregnation, and H2 reduction are used for the hydrodechlorination of lindane and hexachlorobenzene in supercritical carbon dioxide below 100 °C. Both lindane and hexachlorobenzene can be almost 100% transformed to cyclohexane in 1 h. Reaction intermediates, such as lower chlorinated products or benzene, are not observed or exist in trace amount indicating that most of them may undergo reactions without leaving the metal surface. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heat shrinkable behavior, physico-mechanical and structure properties of electron beam cross-linked blends of high-density polyethylene with acrylonitrile-butadiene rubber

NASA Astrophysics Data System (ADS)

Reinholds, Ingars; Kalkis, Valdis; Merijs-Meri, Remo; Zicans, Janis; Grigalovica, Agnese

2016-03-01

In this study, heat-shrinkable composites of electron beam irradiated high-density polyethylene (HDPE) composites with acrylonitrile-butadiene rubber (NBR) were investigated. HDPE/NBR blends at a ratio of components 100/0, 90/10, 80/20, 50/50 and 20/80 wt% were prepared using a two-roll mill. The compression molded films were irradiated high-energy (5 MeV) accelerated electrons up to irradiation absorbed doses of 100-300 kGy. The effect of electron beam induced cross-linking was evaluated by the changes of mechanical properties, gel content and by the differences of thermal properties, detected by differential scanning calorimetry. The thermo-shrinkage forces were determined as the kinetics of thermorelaxation and the residual shrinkage stresses of previously oriented (stretched up to 100% at above melting temperature of HDPE and followed by cooling to room temperature) specimens of irradiated HDPE/NBR blends under isometric heating-cooling mode. The compatibility between the both components was enhanced due to the formation of cross-linked sites at amorphous interphase. The results showed increase of mechanical stiffness of composites with increase of irradiation dose. The values of gel fraction compared to thermorelaxation stresses increased with the growth of irradiation dose level, as a result of formation cross-linked sites in amorphous PP/NBR interphase.

Leak detection in medium density polyethylene (MDPE) pipe using pressure transient method

NASA Astrophysics Data System (ADS)

Amin, M. M.; Ghazali, M. F.; PiRemli, M. A.; Hamat, A. M. A.; Adnan, N. F.

2015-12-01

Water is an essential part of commodity for a daily life usage for an average person, from personal uses such as residential or commercial consumers to industries utilization. This study emphasizes on detection of leaking in medium density polyethylene (MDPE) pipe using pressure transient method. This type of pipe is used to analyze the position of the leakage in the pipeline by using Ensemble Empirical Mode Decomposition Method (EEMD) with signal masking. Water hammer would induce an impulse throughout the pipeline that caused the system turns into a surge of water wave. Thus, solenoid valve is used to create a water hammer through the pipelines. The data from the pressure sensor is collected using DASYLab software. The data analysis of the pressure signal will be decomposed into a series of wave composition using EEMD signal masking method in matrix laboratory (MATLAB) software. The series of decomposition of signals is then carefully selected which reflected intrinsic mode function (IMF). These IMFs will be displayed by using a mathematical algorithm, known as Hilbert transform (HT) spectrum. The IMF signal was analysed to capture the differences. The analyzed data is compared with the actual measurement of the leakage in term of percentage error. The error recorded is below than 1% and it is proved that this method highly reliable and accurate for leak detection.

A hierarchical classification approach for recognition of low-density (LDPE) and high-density polyethylene (HDPE) in mixed plastic waste based on short-wave infrared (SWIR) hyperspectral imaging

NASA Astrophysics Data System (ADS)

Bonifazi, Giuseppe; Capobianco, Giuseppe; Serranti, Silvia

2018-06-01

The aim of this work was to recognize different polymer flakes from mixed plastic waste through an innovative hierarchical classification strategy based on hyperspectral imaging, with particular reference to low density polyethylene (LDPE) and high-density polyethylene (HDPE). A plastic waste composition assessment, including also LDPE and HDPE identification, may help to define optimal recycling strategies for product quality control. Correct handling of plastic waste is essential for its further "sustainable" recovery, maximizing the sorting performance in particular for plastics with similar characteristics as LDPE and HDPE. Five different plastic waste samples were chosen for the investigation: polypropylene (PP), LDPE, HDPE, polystyrene (PS) and polyvinyl chloride (PVC). A calibration dataset was realized utilizing the corresponding virgin polymers. Hyperspectral imaging in the short-wave infrared range (1000-2500 nm) was thus applied to evaluate the different plastic spectral attributes finalized to perform their recognition/classification. After exploring polymer spectral differences by principal component analysis (PCA), a hierarchical partial least squares discriminant analysis (PLS-DA) model was built allowing the five different polymers to be recognized. The proposed methodology, based on hierarchical classification, is very powerful and fast, allowing to recognize the five different polymers in a single step.

Enhanced adherence of mouse fibroblast and vascular cells to plasma modified polyethylene.

PubMed

Reznickova, Alena; Novotna, Zdenka; Kolska, Zdenka; Kasalkova, Nikola Slepickova; Rimpelova, Silvie; Svorcik, Vaclav

2015-01-01

Since the last decade, tissue engineering has shown a sensational promise in providing more viable alternatives to surgical procedures for harvested tissues, implants and prostheses. Biomedical polymers, such as low-density polyethylene (LDPE), high-density polyethylene (HDPE) and ultra-high molecular weight polyethylene (UHMWPE), were activated by Ar plasma discharge. Degradation of polymer chains was examined by determination of the thickness of ablated layer. The amount of an ablated polymer layer was measured by gravimetry. Contact angle, measured by goniometry, was studied as a function of plasma exposure and post-exposure aging times. Chemical structure of modified polymers was characterized by angle resolved X-ray photoelectron spectroscopy. Surface chemistry and polarity of the samples were investigated by electrokinetic analysis. Changes in surface morphology were followed using atomic force microscopy. Cytocompatibility of plasma activated polyethylene foils was studied using two distinct model cell lines; VSMCs (vascular smooth muscle cells) as a model for vascular graft testing and connective tissue cells L929 (mouse fibroblasts) approved for standardized material cytotoxicity testing. Specifically, the cell number, morphology, and metabolic activity of the adhered and proliferated cells on the polyethylene matrices were studied in vitro. It was found that the plasma treatment caused ablation of the polymers, resulting in dramatic changes in their surface morphology and roughness. ARXPS and electrokinetic measurements revealed oxidation of the polymer surface. It was found that plasma activation has a positive effect on the adhesion and proliferation of VSMCs and L929 cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Biological resistance of polyethylene composites made with chemically modified fiber or flour

Treesearch

Rebecca E. Ibach; Craig M. Clemons

2002-01-01

The role of moisture in the biological decay of wood-plastic composites was investigated. Southern pine wood fiber and ponderosa pine wood flour were chemically modified using either acetic anhydride (AA), butylene oxide (BO), or propylene oxide (PO). A 50:50 mixture of high density polyethylene and either chemically modified fiber or flour, or untreated fiber or flour...

Morphology and properties of wood-fiber reinforced blends of recycled polystyrene and polyethylene

Treesearch

John Simonsen; Timothy G. Rials

1996-01-01

Material properties of composites produced from recycled plastics and recycled wood fiber were compared. A blend of high-density polyethylene and polystyrene was used as a simulated mixed plastic. Stiffness was generally improved by the addition of fiber, as expected, but brittleness also increased. Pre-treatment of the wood filler with phenol-formaldehyde resins did...

Synthesis of carbon nanostructures from high density polyethylene (HDPE) and polyethylene terephthalate (PET) waste by chemical vapour deposition

NASA Astrophysics Data System (ADS)

Hatta, M. N. M.; Hashim, M. S.; Hussin, R.; Aida, S.; Kamdi, Z.; Ainuddin, AR; Yunos, MZ

2017-10-01

In this study, carbon nanostructures were synthesized from High Density Polyethylene (HDPE) and Polyethylene terephthalate (PET) waste by single-stage chemical vapour deposition (CVD) method. In CVD, iron was used as catalyst and pyrolitic of carbon source was conducted at temperature 700, 800 and 900°C for 30 minutes. Argon gas was used as carrier gas with flow at 90 sccm. The synthesized carbon nanostructures were characterized by FESEM, EDS and calculation of carbon yield (%). FESEM micrograph shows that the carbon nanostructures were only grown as nanofilament when synthesized from PET waste. The synthesization of carbon nanostructure at 700°C was produced smooth and the smallest diameter nanofilament compared to others. The carbon yield of synthesized carbon nanostructures from PET was lower from HDPE. Furthermore, the carbon yield is recorded to increase with increasing of reaction temperature for all samples. Elemental study by EDS analysis were carried out and the formation of carbon nanostructures was confirmed after CVD process. Utilization of polymer waste to produce carbon nanostructures is beneficial to ensure that the carbon nanotechnology will be sustained in future.

Morphological characterization of selected balloon films and its effects on balloon performances

NASA Technical Reports Server (NTRS)

Said, Magdi A.

1994-01-01

Morphological characterization of several polyethylene balloon films have been studied using various techniques. The objective is to determine, if any, differentiating structural or morphological features that can be related to the performance of these balloon film materials. The results of the study indicate that the films are composed of either linear low denstiy polyethylene (LLDPE) or low density polyethylene (LDPE). A selective examination of these data imply that films limited degree of branching and larger crystallites size (same % crystallinity) showed good mechanical properties that appear to correlate with their high level of success in balloon flights.

Maleic anhydride-g-low density polyethylene: Modification of LDPE molecular structure by γ-irradiation

NASA Astrophysics Data System (ADS)

Sheeja, Manaf, O.; Sujith, A.

2017-06-01

Polymer modification by radiation grafting of monomers onto polymers has received much attention recently. In the current study, γ-irradiation technique was used to achieve graft copolymerization of maleic anhydride (MA) onto low-density polyethylene (LDPE). To optimize, the process was performed at different γ-irradiation doses and MA concentration. The microstructure of grafted polymer film has been characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, field emission-scanning electron microscopy, and atomic force microscopy. The studies performed made possible the selection of experimental protocols adequate for the production of new copolymeric materials with high grafting yield.

High-density polyethylene pipe: A new material for pass-by passive integrated transponder antennas

USGS Publications Warehouse

Kazyak, David C.; Zydlewski, Joseph D.

2012-01-01

Pass-by passive integrated transponder (PIT) antennas are widely used to study the movements of fish in streams. At many sites, stream conditions make it difficult to maintain antennas and obtain a continuous record of movement. We constructed pass-by PIT antennas by using high-density polyethylene (HDPE) and found them to be robust to high flows and winter ice flows. Costs for HDPE antennas were similar to those of traditional polyvinyl chloride (PVC) antennas, although construction was somewhat more complicated. At sites where PVC antennas are frequently damaged, HDPE is a durable and economical alternative for PIT antenna construction.

[Study on biocompatibility of hydroxyapatite/high density polyethylene (HA/HDPE) nano-composites artificial ossicle].

PubMed

Wang, Guohui; Zhu, Shaihong; Tan, Guolin; Zhou, Kechao; Huang, Suping; Zhao, Yanzhong; Li, Zhiyou; Huang, Boyun

2008-06-01

This study was aimed to evaluate the biocompatibility of Hydroxyapatite/High density polyethylene (HA/ HDPE) nano-composites artificial ossicle. The percentage of S-period cells were detected by flow cytometry after L929 cells being incubated with extraction of the HA/HDPE nano-composites; the titanium materials for clinical application served as the contrast. In addition, both materials were implanted in animals and the histopathological evaluations were conducted. There were no statistically significant differences between the two groups (P >0.05). The results demonstrated that the HA/HDPE nano-composite artificial ossicle made by our laboratory is of a good biocompatibility and clinical application outlook.

Development of optimum process for electron beam cross-linking of high density polyethylene thermal energy storage pellets, process scale-up and production of application qualities of material

NASA Technical Reports Server (NTRS)

Salyer, I. O.

1980-01-01

The electron irradiation conditions required to prepare thermally from stable high density polyethylene (HDPE) were defined. The conditions were defined by evaluating the heat of fusion and the melting temperature of several HDPE specimens. The performance tests conducted on the specimens, including the thermal cycling tests in the thermal energy storage unit are described. The electron beam irradiation tests performed on the specimens, in which the total radiation dose received by the pellets, the electron beam current, the accelerating potential, and the atmospheres were varied, are discussed.

Enhancement of the Mechanical Properties of Basalt Fiber-Wood-Plastic Composites via Maleic Anhydride Grafted High-Density Polyethylene (MAPE) Addition

PubMed Central

Chen, Jinxiang; Wang, Yong; Gu, Chenglong; Liu, Jianxun; Liu, Yufu; Li, Min; Lu, Yun

2013-01-01

This study investigated the mechanisms, using microscopy and strength testing approaches, by which the addition of maleic anhydride grafted high-density polyethylene (MAPE) enhances the mechanical properties of basalt fiber-wood-plastic composites (BF-WPCs). The maximum values of the specific tensile and flexural strengths areachieved at a MAPE content of 5%–8%. The elongation increases rapidly at first and then continues slowly. The nearly complete integration of the wood fiber with the high-density polyethylene upon MAPE addition to WPC is examined, and two models of interfacial behavior are proposed. We examined the physical significance of both interfacial models and their ability to accurately describe the effects of MAPE addition. The mechanism of formation of the Model I interface and the integrated matrix is outlined based on the chemical reactions that may occur between the various components as a result of hydrogen bond formation or based on the principle of compatibility, resulting from similar polarity. The Model I fracture occurred on the outer surface of the interfacial layer, visually demonstrating the compatibilization effect of MAPE addition. PMID:28809285

Enhanced Thermal Conductivity and Dielectric Properties of Iron Oxide/Polyethylene Nanocomposites Induced by a Magnetic Field.

PubMed

Chi, Qingguo; Ma, Tao; Dong, Jiufeng; Cui, Yang; Zhang, Yue; Zhang, Changhai; Xu, Shichong; Wang, Xuan; Lei, Qingquan

2017-06-08

Iron Oxide (Fe 3 O 4 ) nanoparticles were deposited on the surface of low density polyethylene (LDPE) particles by solvothermal method. A magnetic field was introduced to the preparation of Fe 3 O 4 /LDPE composites, and the influences of the magnetic field on thermal conductivity and dielectric properties of composites were investigated systematically. The Fe 3 O 4 /LDPE composites treated by a vertical direction magnetic field exhibited a high thermal conductivity and a large dielectric constant at low filler loading. The enhancement of thermal conductivity and dielectric constant is attributed to the formation of the conductive chains of Fe 3 O 4 in LDPE matrix under the action of the magnetic field, which can effectively enhance the heat flux and interfacial polarization of the Fe 3 O 4 /LDPE composites. Moreover, the relatively low dielectric loss and low conductivity achieved are attributed to the low volume fraction of fillers and excellent compatibility between Fe 3 O 4 and LDPE. Of particular note is the dielectric properties of Fe 3 O 4 /LDPE composites induced by the magnetic field also retain good stability across a wide temperature range, and this contributes to the stability and lifespan of polymer capacitors. All the above-mentioned properties along with the simplicity and scalability of the preparation for the polymer nanocomposites make them promising for the electronics industry.

Radiation Transport Properties of Polyethylene-Fiber Composites

NASA Technical Reports Server (NTRS)

Kaul, Raj K.; Barghouty, A. F.; Dahche, H. M.

2003-01-01

Composite materials that can both serve as effective shielding materials against cosmic-ray and energetic solar particles in deep space as well as structural materials for habitat and spacecraft remain a critical and mission enabling piece in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density coupled with high hydrogen content. Polyethylene fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of Polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at NASA's Marshall Space Flight Center and tested against 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

Space radiation transport properties of polyethylene-based composites.

PubMed

Kaul, R K; Barghouty, A F; Dahche, H M

2004-11-01

Composite materials that can serve as both effective shielding materials against cosmic-ray and energetic solar particles in deep space, as well as structural materials for habitat and spacecraft, remain a critical and mission enabling component in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density, coupled with high hydrogen content. Polyethylene-fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at the NASA Marshall Space Flight Center and tested against a 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

Combating oil spill problem using plastic waste.

PubMed

Saleem, Junaid; Ning, Chao; Barford, John; McKay, Gordon

2015-10-01

Thermoplastic polymers (such as polypropylene, polyethylene, polyethylene terephthalate (PET) and high density polyethylene (HDPE)) constitute 5-15% of municipal solid waste produced across the world. A huge quantity of plastic waste is disposed of each year and is mostly either discarded in landfills or incinerated. On the other hand, the usage of synthetic polymers as oil sorbents, in particular, polyolefins, including polypropylene (PP), and polyethylene (PE) are the most commonly used oil sorbent materials mainly due to their low cost. However, they possess relatively low oil absorption capacities. In this work, we provide an innovative way to produce a value-added product such as oil-sorbent film with high practical oil uptake values in terms of g/g from waste HDPE bottles for rapid oil spill remedy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Space radiation transport properties of polyethylene-based composites

NASA Technical Reports Server (NTRS)

Kaul, R. K.; Barghouty, A. F.; Dahche, H. M.

2004-01-01

Composite materials that can serve as both effective shielding materials against cosmic-ray and energetic solar particles in deep space, as well as structural materials for habitat and spacecraft, remain a critical and mission enabling component in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density, coupled with high hydrogen content. Polyethylene-fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at the NASA Marshall Space Flight Center and tested against a 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

A Compendium of Thermoplastic Polymer Pyrograms

DTIC Science & Technology

2002-07-01

poly(ethylene)........................................................................... 3 Figure 2 . Pyrogram of a sample of high density poly(ethylene... 2 -methylphenol and 3 -methylphenol (12.09 min and 12.46 min), 3,5-dimethylphenyl 4-hydroxy- 2 -methylphenyl ether (26.35 min). 5.00 10.00 15.00 20.00...hydroxybenzaldehyde (17.13), biphenyl (17.74 min), diphenylether (18.05 min), hydroxybenzoic acid (19.51 min), 2 -hydroxybiphenyl (19.64 min), dibenzofuran

The effects of oil-in-water nanoemulsion polyethylene glycol surface density on intracellular stability, pharmacokinetics, and biodistribution in tumor bearing mice.

PubMed

Hak, Sjoerd; Garaiova, Zuzana; Olsen, Linda Therese; Nilsen, Asbjørn Magne; de Lange Davies, Catharina

2015-04-01

Lipid-based nanoparticles are extensively studied for drug delivery. These nanoparticles are often surface-coated with polyethylene glycol (PEG) to improve their biodistribution. Until now, the effects of varying PEG surface density have been studied in a narrow and low range. Here, the effects of high and a broad range of PEG surface densities on the in vivo performance of lipid-based nanoparticles were studied. Oil-in-water nanoemulsions were prepared with PEG surface densities of 5-50 mol%. Confocal microscopy was used to assess intracellular disintegration in vitro. In vivo pharmacokinetics and biodistribution in tumor bearing mice were studied using a small animal optical imager. PEG surface density did not affect intracellular nanoemulsion stability. Surprisingly, circulation half-lives decreased with increasing PEG surface density. A plausible explanation was that nanoemulsion with high (50 mol%) PEG surface density activated the complement in a whole blood assay, whereas nanoemulsion with low (5 mol%) PEG density did not. In vivo, nanoemulsion with low PEG surface density was mostly confined to the tumor and organs of the mononuclear phagocyte system, whereas nanoemulsion with high PEG density accumulated throughout the mouse. Optimal PEG surface density of lipid-based nanoparticles for tumor targeting was found to be below 10 mol%.

A hierarchical classification approach for recognition of low-density (LDPE) and high-density polyethylene (HDPE) in mixed plastic waste based on short-wave infrared (SWIR) hyperspectral imaging.

PubMed

Bonifazi, Giuseppe; Capobianco, Giuseppe; Serranti, Silvia

2018-06-05

The aim of this work was to recognize different polymer flakes from mixed plastic waste through an innovative hierarchical classification strategy based on hyperspectral imaging, with particular reference to low density polyethylene (LDPE) and high-density polyethylene (HDPE). A plastic waste composition assessment, including also LDPE and HDPE identification, may help to define optimal recycling strategies for product quality control. Correct handling of plastic waste is essential for its further "sustainable" recovery, maximizing the sorting performance in particular for plastics with similar characteristics as LDPE and HDPE. Five different plastic waste samples were chosen for the investigation: polypropylene (PP), LDPE, HDPE, polystyrene (PS) and polyvinyl chloride (PVC). A calibration dataset was realized utilizing the corresponding virgin polymers. Hyperspectral imaging in the short-wave infrared range (1000-2500nm) was thus applied to evaluate the different plastic spectral attributes finalized to perform their recognition/classification. After exploring polymer spectral differences by principal component analysis (PCA), a hierarchical partial least squares discriminant analysis (PLS-DA) model was built allowing the five different polymers to be recognized. The proposed methodology, based on hierarchical classification, is very powerful and fast, allowing to recognize the five different polymers in a single step. Copyright © 2018 Elsevier B.V. All rights reserved.

Beneficial effects of polyethylene packages containing micrometer-sized silver particles on the quality and shelf life of dried barberry (Berberis vulgaris).

PubMed

Motlagh, N Valipoor; Mosavian, M T Hamed; Mortazavi, S A; Tamizi, A

2012-01-01

In this research, the effects of low-density polyethylene (LDPE) packages containing micrometer-sized silver particles (LDPE-Ag) on microbial and sensory factors of dried barberry were investigated in comparison with the pure LDPE packages. LDPE-Ag packages with 1% and 2% concentrations of silver particles statistically caused a decrease in the microbial growth of barberry, especially in the case of mold and total bacteria count, compared with the pure LDPE packages. The taste, aroma, appearance, and total acceptance were evaluated by trained panelists using the 9-point hedonic scale. This test showed improvement of all these factors in the samples related to packages containing 1% and 2% concentrations of silver particles in comparison with other samples. Low-density polyethylene package containing micrometer-sized silver particles had beneficial effects on the sensory and microbial quality of barberry when compared with normal packing material. © 2011 Institute of Food Technologists®

Chemical recycling of plastic wastes made from polyethylene (LDPE and HDPE) and polypropylene (PP).

PubMed

Achilias, D S; Roupakias, C; Megalokonomos, P; Lappas, A A; Antonakou, Epsilon V

2007-11-19

The recycling of either model polymers or waste products based on low-density polyethylene (LDPE), high-density polyethylene (HDPE) or polypropylene (PP) is examined using the dissolution/reprecipitation method, as well as pyrolysis. In the first technique, different solvents/non-solvents were examined at different weight percent amounts and temperatures using as raw material both model polymers and commercial products (packaging film, bags, pipes, food-retail outlets). The recovery of polymer in every case was greater than 90%. FT-IR spectra and tensile mechanical properties of the samples before and after recycling were measured. Furthermore, catalytic pyrolysis was carried out in a laboratory fixed bed reactor with an FCC catalyst using again model polymers and waste products as raw materials. Analysis of the derived gases and oils showed that pyrolysis gave a mainly aliphatic composition consisting of a series of hydrocarbons (alkanes and alkenes), with a great potential to be recycled back into the petrochemical industry as a feedstock for the production of new plastics or refined fuels.

Effect of ultraviolet radiation in the photo-oxidation of High Density Polyethylene and Biodegradable Polyethylene films

NASA Astrophysics Data System (ADS)

Martínez-Romo, A.; González Mota, R.; Bernal, J. J. Soto; Frausto Reyes, C.; Rosales Candelas, I.

2015-01-01

One of the most widely used plastics in the world is the High density polyethylene (HDPE), it is a stable material due to its carbon-carbon bonds, causing their slow degradation; which is why we are looking for alternative ways to accelerate the degradation process of this polymer. An alternative is the addition of oxidized groups in its molecular structure, which results in the development of polymers susceptible to biodegradation (PE-BIO). In this paper, HDPE and PE-BIO films were exposed to UV-B radiation (320-280 nm) at different exposure times, 0-60 days. The effects of UV radiation in samples of HDPE and PE-BIO were characterized using infrared spectroscopy with attenuated total reflectance (ATR). The results show that the exposed materials undergo changes in their molecular structure, due to the infrared bands formed which corresponds to the photo-oxidation of HDPE and PE films when submitted to UV-B radiation.

Using the MCNP Taylor series perturbation feature (efficiently) for shielding problems

NASA Astrophysics Data System (ADS)

Favorite, Jeffrey

2017-09-01

The Taylor series or differential operator perturbation method, implemented in MCNP and invoked using the PERT card, can be used for efficient parameter studies in shielding problems. This paper shows how only two PERT cards are needed to generate an entire parameter study, including statistical uncertainty estimates (an additional three PERT cards can be used to give exact statistical uncertainties). One realistic example problem involves a detailed helium-3 neutron detector model and its efficiency as a function of the density of its high-density polyethylene moderator. The MCNP differential operator perturbation capability is extremely accurate for this problem. A second problem involves the density of the polyethylene reflector of the BeRP ball and is an example of first-order sensitivity analysis using the PERT capability. A third problem is an analytic verification of the PERT capability.

An improved model to estimate trapping parameters in polymeric materials and its application on normal and aged low-density polyethylenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ning, E-mail: nl4g12@soton.ac.uk; He, Miao; Alghamdi, Hisham

2015-08-14

Trapping parameters can be considered as one of the important attributes to describe polymeric materials. In the present paper, a more accurate charge dynamics model has been developed, which takes account of charge dynamics in both volts-on and off stage into simulation. By fitting with measured charge data with the highest R-square value, trapping parameters together with injection barrier of both normal and aged low-density polyethylene samples were estimated using the improved model. The results show that, after long-term ageing process, the injection barriers of both electrons and holes is lowered, overall trap depth is shallower, and trap density becomesmore » much greater. Additionally, the changes in parameters for electrons are more sensitive than those of holes after ageing.« less

Preparation and release study of Triclosan in polyethylene/Triclosan anti-bacterial blend.

PubMed

Kamalipour, Jamshid; Masoomi, Mahmood; Khonakdar, Hossein Ali; Razavi, Seyed Mohammad Reza

2016-09-01

In this study, medium density polyethylene (MDPE) incorporated with Triclosan antibacterial substance has been prepared and Triclosan release rate was investigated. The crystallinity level and matrix polarity, as two significant parameters in antibacterial release control, were studied. Triclosan, a well-established widespread antibacterial agent, was incorporated into medium density polyethylene (MDPE) and Maleic anhydride grafted polyethylene (PE-g-MA) was used to change the polarity of the MDPE matrix. A masterbatch of 10wt% Triclosan incorporated with the MDPE and various PE-g-MA concentrations were prepared using an internal mixer. Then the masterbatch was diluted in the MDPE matrix to produce compounds with 0.1, 0.5, and1wt% Triclosan via twin screw extruder. The compounds were molded by compression molding method and then were cooled in three different cooling rate methods: isothermal cooling (I), quenching (Q),and moderate 5-10°C/min cooling rate (M). Cooling rate effects on crystallinity level were investigated applying sample density measurement. UV-vis absorption spectroscopy was used to probe the release of Triclosan. Antibacterial properties of the compounds against Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were measured. The results showed that by addition of PE-g-MA, Triclosan release rate was increased. It was confirmed that the sample crystallinity was decreased by the cooling rate enhancement. The results also showed that quenched samples indicated higher release of Triclosan. Cooling rate reduction and raising the polarity increased the release of Triclosan and improved the antibacterial properties of the compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

The modification of renal transplantation with the usage of own polyethylene receptacle.

PubMed

Pupka, Artur; Chudoba, Paweł; Patrzałek, Dariusz; Janczak, Dariusz; Szyber, Piotr

2003-01-01

In this study a method of elimination of the second warm ischemia is shown. The method is based on the application of a specially constructed polyethylene bag, in which the transplanted kidney is placed in the time course from a removal from ice to the reconstruction of vessel flow. The bag is built of polyethylene foil HDPE of low density produced under high pressure. Own construction of the bag (three spaces and polyethylene) enables the storage of a transplanted organ at the stable temperature +4 Celsius degrees. Thanks to the separation of containers for melting ice and for the kidney, possible becomes unrestrained performance of both venous and arterial anastomosis independently of existing operative conditions. Due to the applied method of the elimination of the second warm ischemia with the usage of own construction of polyethylene bag HDPE, one can expect better early renal function after transplantation--decrease in the number of cases and shortening of the time of acute tubular necrosis (ATN--Acute Tubular Necrosis).

Development of radiation resistant electrical cable insulations

NASA Technical Reports Server (NTRS)

Lee, B. S.; Soo, P.; Mackenzie, D. R.

1994-01-01

Two new polyethylene cable insulations have been formulated for nuclear applications and have been tested under gamma radiation. Both insulations are based on low density polyethylene, one with PbO and the other with Sb2O3 as additives. The test results show that the concept of using inorganic antioxidants to retard radiation initiated oxidation (RIO) is viable. PbO is more effective than Sb2O3 in minimizing RIO.

Effect of Ar ion on the surface properties of low density polyethylene

NASA Astrophysics Data System (ADS)

Zaki, M. F.

2016-04-01

In this paper, low-density polyethylene (LDPE) was irradiated by argon ion with different fluences up to 1015ions/cm2. The optical, chemical and hardness properties have been investigated using UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and micro-indentation tester, respectively. The results showed the ion beam bombardment induced decreases in the transmittance of the irradiated polymer samples. This change in transmittance can be attributed to the formation of conjugated bonds i.e. possible formation of defects and/or carbon clusters. The indirect optical band gap decreased from 3.0 eV for the pristine sample to 2.3 eV for that sample irradiated with the highest fluence of the Ar ion beam. Furthermore, the number of carbon atoms and clusters increased with increasing Ar ion fluences. FTIR spectra showed the formation of new bands of the bombarded polymer samples. Furthermore, polar groups were created on the surface of the irradiated samples which refer to the increase of the hydrophilic nature of the surface of the irradiated samples. The Vicker's hardness increased from 4.9 MPa for the pristine sample to 17.9 MPa for those bombarded at the highest fluence. This increase is attributed to the increase in the crosslinking and alterations of the bombarded surface into hydrogenated amorphous carbon, which improves the hardness of the irradiated samples. The bombarded LDPE surfaces may be used in special applications to the field of the micro-electronic devices and shock absorbers.

Retraction of cold drawn polyethylene: the influence of lamellar thickeness and density

NASA Technical Reports Server (NTRS)

Falender, J. R.; Hansen, D.

1971-01-01

The role of crystal morphology in the retraction of oriented, linear polyethylene was studied utilizing samples crystallized under conditions controlled to vary, separately, lamellar crystal thickness and density. Samples were oriented in a simple shear deformation to a strain of 4.0 prior to measuring retraction tendency in creep and relaxation type tests. Characterizations of specimens were made using wide and small angle X-ray techniques. The specific morphological variations were chosen to test the hypothesis that a long range elastic restoring force can originate in conjunction with deformation of lamellar crystals and the consequent increase in lamellar crystal surface area and surface free energy. The results support this hypothesis.

Retraction of cold-drawn polyethylene - Influence of lamellar thickness and density.

NASA Technical Reports Server (NTRS)

Falender, J. R.; Hansen, D.

1972-01-01

The role of crystal morphology in the retraction of oriented linear polyethylene was studied utilizing samples crystallized under conditions controlled to vary, separately, lamellar crystal thickness and density. Samples were oriented in a simple shear deformation to a strain of 4.0 prior to measuring retraction tendency in creep- and relaxation-type tests. Characterizations of specimens were made using wide- and small-angle x-ray techniques. The specific morphological variations were chosen to test the hypothesis that a long-range elastic restoring force can originate in conjunction with deformation of lamellar crystals and the consequent increase in lamellar crystal surface area and surface free energy. The results support this hypothesis.

Low-cost thin-film absorber/evaporator for an absorption chiller. Final report, May 1992-April 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowenstein, A.; Sibilia, M.

1993-04-01

The feasibility of making the absorber and evaporator of a small lithium-bromide absorption chiller from thin plastic films was studied. Tests were performed to measure (1) pressure limitations for a plastic thin-film heat exchanger, (2) flow pressure-drop characteristics, (3) air permeation rates across the plastic films, and (4) creep characteristics of the plastic films. Initial tests were performed on heat exchangers made of either low-density polyethylene (LDPE), high-density polyethylene (HDPE), or a LDPE/HDPE blend. While initial designs for the heat exchanger failed at internal pressures of only 5 to 6 psi, the final design could withstand pressures of 34 psi.

The impact of electron beam irradiation on Low density polyethylene and Ethylene vinyl acetate

NASA Astrophysics Data System (ADS)

Sabet, Maziyar; Soleimani, Hassan

2017-05-01

Improvement of measured gel content, hardness, tensile strength and elongation at break of Ethylene vinyl acetate (EVA) have confirmed positive effect of electron beam irradiation on EVA. Results obtained from both gel content tests show that degree of cross-linking in amorphous regions is dependent on dose. A significant improvement in tensile strength of neat EVA samples is obtained upon electron-beam radiation up to 210 kGy. Similarly, hardness properties of Low-density polyethylene (LDPE) improvewith increasing electron beam irradiation. This article deals with the impacts of electron beam (EB) irradiation on the properties of LDPE and Ethylene-Vinyl Acetate (EVA) as the two common based formulations for wire and cable applications.

Effect of gamma irradiation on high temperature hardness of low-density polyethylene

NASA Astrophysics Data System (ADS)

Chen, Pei-Yun; Yang, Fuqian; Lee, Sanboh

2015-11-01

Gamma irradiation can cause the change of microstructure and molecular structure of polymer, resulting in the change of mechanical properties of polymers. Using the hardness measurement, the effect of gamma irradiation on the high temperature hardness of low-density polyethylene (LDPE) was investigated. The gamma irradiation caused the increase in the melting point, the enthalpy of fusion, and the portion of crystallinity of LDPE. The Vickers hardness of the irradiated LDPE increases with increasing the irradiation dose, annealing temperature, and annealing time. The activation energy for the rate process controlling the reaction between defects linearly decreases with the irradiation dose. The process controlling the hardness evolution in LDPE is endothermic because LDPE is semi-crystalline.

A novel wood flour-filled composite based on microfibrillar high-density polyethylene (HDPE)/Nylon-6 blends.

PubMed

Liu, Hongzhi; Yao, Fei; Xu, Yanjun; Wu, Qinglin

2010-05-01

A novel wood flour (WF)-filled composite based on the microfibrillar high-density polyethylene (HDPE) and Nylon-6 co-blend, in which both in situ formed Nylon-6 microfibrils and WF acted as reinforcing elements, was successfully developed using a two-step extrusion method. At the 30wt.% WF loading level, WF-filled composite based on the microfibrillized HDPE/Nylon-6 blend exhibited higher strengths and moduli than the corresponding HDPE-based composite. The incorporation of WF reduced short-term creep response of HDPE matrix and the presence of Nylon-6 microfibrils further contributed to the creep reduction. Copyright 2009 Elsevier Ltd. All rights reserved.

Shear and elongational rheology of photo-oxidative degraded HDPE and LLDPE

NASA Astrophysics Data System (ADS)

Wagner, Manfred Hermann; Zheng, Wang; Wang, Peng; Talamante, Sebastián Ramos; Narimissa, Esmaeil

2017-05-01

The effect of photo-oxidative degradation of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) was investigated by linear and non-linear rheological measurements. The linear-viscoelastic rheological measurements were performed at different temperatures, while the elongational viscosity was measured at 170°C and at different strain rates. The rheological data are indicative of structural changes caused by photo-oxidative degradation including formation of long-chain branches (LCB), cross-linking, and chain scission, and they revealed a cyclic and continuing competition between chain scission and LCB/gel formation. These findings are supported by additional FTIR measurements and direct measurements of the gel content of the degraded samples.

Determination of Thermal Properties and Morphology of Eucalyptus Wood Residue Filled High Density Polyethylene Composites

PubMed Central

Mengeloglu, Fatih; Kabakci, Ayse

2008-01-01

Thermal behaviors of eucalyptus wood residue (EWR) filled recycled high density polyethylene (HDPE) composites have been measured applying the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Morphology of the materials was also studied using scanning electron microscope (SEM). Addition of the EWR into the recycled HDPE matrix reduced the starting of degradation temperature. EWR filled recycled HDPE had two main decomposition peaks, one for EWR around 350 °C and one for recycled HDPE around 460 °C. Addition of EWR did not affect the melting temperature of the recycled HDPE. Morphological study showed that addition of coupling agent improved the compatibility between wood residue and recycled HDPE. PMID:19325736

Adhesion and Growth of Vascular Smooth Muscle Cells on Nanostructured and Biofunctionalized Polyethylene

PubMed Central

Novotna, Katarina; Bacakova, Marketa; Kasalkova, Nikola Slepickova; Slepicka, Petr; Lisa, Vera; Svorcik, Vaclav; Bacakova, Lucie

2013-01-01

Cell colonization of synthetic polymers can be regulated by physical and chemical modifications of the polymer surface. High-density and low-density polyethylene (HDPE and LDPE) were therefore activated with Ar+ plasma and grafted with fibronectin (Fn) or bovine serum albumin (BSA). The water drop contact angle usually decreased on the plasma-treated samples, due to the formation of oxidized groups, and this decrease was inversely related to the plasma exposure time (50–300 s). The presence of nitrogen and sulfur on the polymer surface, revealed by X-ray photoelectron spectroscopy (XPS), and also by immunofluorescence staining, showed that Fn and BSA were bound to this surface, particularly to HDPE. Plasma modification and grafting with Fn and BSA increased the nanoscale surface roughness of the polymer. This was mainly manifested on HDPE. Plasma treatment and grafting with Fn or BSA improved the adhesion and growth of vascular smooth muscle cells in a serum-supplemented medium. The final cell population densities on day 6 after seeding were on an average higher on LDPE than on HDPE. In a serum-free medium, BSA grafted to the polymer surface hampered cell adhesion. Thus, the cell behavior on polyethylene can be modulated by its type, intensity of plasma modification, grafting with biomolecules, and composition of the culture medium. PMID:28809234

Thermal Diffusivity of High-Density Polyethylene Samples of Different Crystallinity Evaluated by Indirect Transmission Photoacoustics

NASA Astrophysics Data System (ADS)

Nesic, M.; Popovic, M.; Rabasovic, M.; Milicevic, D.; Suljovrujic, E.; Markushev, D.; Stojanovic, Z.

2018-02-01

In this work, thermal diffusivity of crystalline high-density polyethylene samples of various thickness, and prepared using different procedures, was evaluated by transmission gas-microphone frequency photoacoustics. The samples' composition analysis and their degree of crystallinity were determined from the wide-angle X-ray diffraction, which confirmed that high-density polyethylene samples, obtained by slow and fast cooling, were equivalent in composition but with different degrees of crystallinity. Structural analysis, performed by differential scanning calorimetry, demonstrated that all of the used samples had different levels of crystallinity, depending not only on the preparing procedure, but also on sample thickness. Therefore, in order to evaluate the samples' thermal diffusivity, it was necessary to modify standard photoacoustic fitting procedures (based on the normalization of photoacoustic amplitude and phase characteristics on two thickness levels) for the interpretation of photoacoustic measurements. The calculated values of thermal diffusivity were in the range of the expected literature values. Besides that, the obtained results indicate the unexpected correlation between the values of thermal diffusivity and thermal conductivity with the degree of crystallinity of the investigated geometrically thin samples. The results indicate the necessity of additional investigation of energy transport in macromolecular systems, as well as the possible employment of the photoacoustic techniques in order to clarify its mechanism.

Investigation of mechanical, thermal and recycled characteristics of reinforced ternary blends of LDPE/LLDPE/HDPE by ANOVA

NASA Astrophysics Data System (ADS)

Maleki, Mahnam; Farzin, Mahmud; Mosaddegh, Peiman

2018-06-01

In this study, the effect of high density polyethylene (HDPE) and calcium carbonate (CaCO3) addition into constant amount of low density polyethylene/linear low density polyethylene (LDPE/LLDPE) matrix was investigated by using different mechanical and thermal parameters. Then, analysis of variance (ANOVA) was used to investigate the normal distribution of obtained data. Finally, sample containing 50 Phr of HDPE and 7 Phr of CaCO3 microparticles, was determined as optimized sample. The effect of different process parameters such as injecting back pressure, cooling and retention time, on mechanical and thermal properties of optimized sample was investigated as well. Also to investigate the effect of the number of recycling processes on the mechanical and thermal properties, two dominant degradation mechanisms were suggested. The first was the decreasing of chains molecular weight and formation of short length chains and the later was the formation of crosslinks and three dimensional networks. Results indicated that by increasing the number of recycling processes, crystallinity, melting point, modulus, strength at yielding point and toughness in comparison to pristine sample decreased at first and then showed an ascending trend. Elongation at break by increasing of the number of recycling processes, generally increased in comparison with initial sample.

Effects of raw materials on the properties of wood fiber-polyethylene composites--part 3: effect of a compatibilizer and wood adhesive on the interfacial adhesion of wood/plastic composites

Treesearch

Chin-yin Hwang; Chung-yun Hse; Todd F. Shupe

2008-01-01

The objective of this study was to examine the effect of maleated polypropylene compatabilizer on the interfacial properties of wood and polyolefins. Birch wood dowels containing an adhesive applied on the surface were embedded in molten plastic matrices using specially designed jigs. The three plastics investigated included low density polyethylene (LFPE), linear low...

Study of mechanical and morphological properties of bio-based polyethylene (HDPE) and sponge-gourds (Luffa-cylindrica) agroresidue composites

NASA Astrophysics Data System (ADS)

Escocio, Viviane A.; Visconte, Leila L. Y.; Cavalcante, Andre de P.; Furtado, Ana Maria S.; Pacheco, Elen B. A. V.

2015-05-01

Brazil has a remarkable position in the use of renewable energy. The potential of natural resources in Brazil has motivated the use of these renewable resources to make technologies more sustainable. From the large variety of commercially available High Density Polyethylene (HDPE) from different sources, two were chosen for investigation: one produced from sugarcane ethanol, and the other one, a conventional polyethylene, produced from fossil resources. In the preparation of the composites, sponge-gourds also called Luffa cylindrica were selectec. The main application of this product is as bath sponge, whose production generates scraps that are generally burnt. In this work, the composites were prepared by blending the sponge scrap at different proportions (10, 20, 30 and 40% wt/wt) with high density polyethylene (HDPE) from renewable source by extrusion. The melt flow index analysis of the composites was determined and specimens were obtained by injection molding for the assessment of mechanical properties such as tensile (elasticity modulus), flexural and Izod impact strengths. The microstructure of the impact fractured surface of the specimen also was determined. The results showed that the addition of sponge scrap affects positively all the properties studied as compared to HDPE. The results of tensile strength, elasticity modulus and flexural strength were similar to those observed in the literature for composites of HDPE from fossil source. The microstructure corroborates the results of mechanical properties. It was shown that the sponge scrap has potential to be applied as cellulosic filler for renewable polyethylene, providing a totally renewable material with good mechanical properties.

Characterization of solidified radioactive waste due to the incorporation of high- and low-density polyethylene granules and titanium dioxide in mortar matrices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peric, A.

1997-12-31

The rutile form of titanium dioxide and granules of high density polyethylene (PEHD) and low density polyethylene (PELD) were used to prepare mortar matrices for immobilization of radioactive waste materials containing {sup 137}Cs. PELD, PEHD and TiO{sub 2} were added to mortar matrix preparations with the objective of improving physico-chemical characteristics of the radwaste-mortar matrix mixtures, in particular the leach-rate of the immobilized radionuclide. One type of PELD and two types of PEHD were used to replace 50 wt.% of stone granules normally used in the matrix, in order to decrease the porosity and density of the mortar matrix andmore » to avoid segregation of the stone particles at the bottom of the immobilized radioactive waste cylindrical form. TiO{sub 2} was also added to the mortar formulation, replacing 5 and 8 wt.% of the total cement weight. Cured samples were investigated under temperature stress conditions, where the temperature extremes were: T{sub min} = {minus}20 C, T{sub max} = +70 C. Samples were periodically immersed in distilled water at the ambient room temperature, after each freezing and heating treatment. Results of accelerated leaching experiments for these samples and samples prepared exclusively with polyethylenes replacing 100% of the stone granules and TiO{sub 2}, treated in nonaccelerated leaching experiments, were compared. Even using an accelerated ageing leach test that overestimates {sup 137}Cs leach rates, it can be deduced, that radionuclide leach rates from the radioactive waste mortar mixture forms were improved. Leach rates decreased from 5%, for the material prepared with stone aggregate, to 3.1 to 4.0%, for the materials prepared solely with PEHD, PELD or TiO{sub 2}, and to about 3% for all six types of the TiO{sub 2}-PEHD and TiO{sub 2}-PELD mixtures tested.« less

Oil-Impregnated Polyethylene Films

NASA Astrophysics Data System (ADS)

Mukherjee, Ranit; Habibi, Mohammad; Rashed, Ziad; Berbert, Otacilio; Shi, Shawn; Boreyko, Jonathan

2017-11-01

Slippery liquid-infused porous surfaces (SLIPS) minimize the contact angle hysteresis of a wide range of liquids and aqueous food products. Although hydrophobic polymers are often used as the porous substrate for SLIPS, the choice of polymer has been limited to silicone-based or fluorine-based materials. Hydrocarbon-based polymers, such as polyethylene, are cost effective and widely used in food packaging applications where SLIPS would be highly desirable. However, to date there have been no reports on using polyethylene as a SLIPS substrate, as it is considered highly impermeable. Here, we show that thin films of low-density polyethylene can be stably impregnated with carbon-based oils without requiring any surface modification. Wicking tests reveal that oils with sufficient chemical compatibility follow Washburn's equation. The nanometric effective pore size of the polyethylene does result in a very low wicking speed, but by using micro-thin films and a drawdown coater, impregnation can still be completed in under one second. The oil-impregnated polyethylene films promoted ultra-slippery behavior for water, ketchup, and yogurt while remaining durable even after being submerged in ketchup for over one month. This work was supported by Bemis North America (AT-23981).

The morphology of blends of linear and branched polyethylenes in solid state by SANS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wignall, G.D.; Londono, J.D.; Alamo, R.G.

1994-12-31

In a previous paper the authors have shown how small-angle neutron and X-ray scattering (SANS, SAXS) can be used to determine the melt compatibility of different polyolefins, including high-density (HD), low-density (LD), and linear low density (LLD) polyethylene. Such blends have attained widespread commercial applications, though the understanding of the mechanical and melt-flow properties of such blends has hitherto been handicapped by the absence of a consensus concerning the degree of mixing of the components, both in the melt and solid states. Recent SANS data indicate that for HDPE/LDPE blends, the melt is homogeneous for all compositions after proper accountingmore » for H/D isotope effects. In this publication the authors use complementary SANS, DSC, and SAXS to examine the types of morphologies and the different degrees of phase separation which may arise via crystallization effects on cooling from a homogeneous melt.« less

The morphology of blends of linear and branched polyethylenes in solid state by SANS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wignall, G.D.; Londono, J.D.; Alamo, R.G.

1995-03-01

In a previous paper, the authors have shown how small-angle neutron and X-ray scattering (SANS, SAXS) can be used to determine the melt compatibility of different polyolefins, including high-density (HD), low-density (LD), and linear low density (LLD) polyethylene. Such blends have attained widespread commercial applications, though the understanding of the mechanical and melt-flow properties of such blends has hitherto been handicapped by the absence of a consensus concerning the degree of mixing of the components, both in the melt and solid states. Recent SANS data indicate that for HDPE/LDPE blends, the melt is homogeneous for all compositions after proper accountingmore » for H/D isotope effects. In this publication the authors use complementary SANS, DSC, and SAXS to examine the types of morphologies and the different degrees of phase separation which may arise via crystallization effects on cooling from a homogeneous melt.« less

40 CFR 52.375 - Certification of no sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of High-density Polyethylene and Polypropylene Resins. (e) Synthetic organic chemical manufacturing industry (SOCMI) distillation. (f) Synthetic organic chemical manufacturing industry (SOCMI) reactor...

Nucleation and growth of apatite on NaOH-treated PEEK, HDPE and UHMWPE for artificial cornea materials.

PubMed

Pino, M; Stingelin, N; Tanner, K E

2008-11-01

The skirt of an artificial cornea must integrate the implant to the host sclera, a major failure of present devices. Thus, it is highly desirable to encourage the metabolic activity of the cornea by using more bioactive, flexible skirt materials. Here we describe attempts to increase the bioactivity of polyether ether ketone (PEEK), high-density polyethylene (HDPE) and ultra-high molecular weight polyethylene (UHMWPE) films. The effectiveness of different strength NaOH pre-treatments to initiate apatite deposition on PEEK, HDPE and UHMWPE is investigated. We find that exposure of PEEK, HDPE and UHMWPE films to NaOH solutions induces the formation of potential nuclei for apatite (calcium phosphate), from which the growth of an apatite coating is stimulated when subsequently immersing the polymer films in 1.5 strength Simulated Body Fluid (SBF). As immersion time in SBF increases, further nucleation and growth produces a thicker and more compact apatite coating that can be expected to be highly bioactive. Interestingly, the apatite growth is found to also be dependent on both the concentration of NaOH solution and the structure of the polymer surface.

Probing Nucleation and Growth Behavior of Twisted Kebabs from Shish Scaffold in Sheared Polyethylene Melts by in situ X-ray Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keum,J.; Burger, C.; Zuo, F.

2007-01-01

By utilizing synchrotron rheo-WAXD (wide-angle X-ray diffraction) and rheo-SAXS (small-angle X-ray scattering) techniques, the nucleation and growth behavior of twisted kebabs from the shear-induced shish scaffold in entangled high-density polyethylene (HDPE) melts were investigated. The evolution of the (110) reflection intensity in WAXD at the early stages of crystallization could be described by a simplified Avrami equation, while the corresponding long period of kebabs determined by SAXS was found to decrease with time. The combined SAXS and WAXD results indicate that the kebab growth in sheared HDPE melts consists of two-dimensional geometry with thermal (sporadic) nucleation. The WAXD data clearlymore » exhibited the transformations of (110) reflection from equatorial 2-arc to off-axis 4-arc and of (200) reflection from off-axis 4-arc to meridional 2-arc, which can be explained by the rotation of crystallographic a-axis around the b-axis during twisted kebab growth. This observation is also consistent with the orientation mode changes from 'Keller/Machin II' to 'intermediate' and then to 'Keller/Machin I'.« less

Dielectric response of high permittivity polymer ceramic composite with low loss tangent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subodh, G.; 1.Physikalisches Institut, Universitat Stuttgart, Pfaffenwaldring 57, Stuttgart 70550; Deepu, V.

2009-08-10

The present communication investigates the dielectric response of the Sr{sub 9}Ce{sub 2}Ti{sub 12}O{sub 36} ceramics loaded high density polyethylene and epoxy resin. Sr{sub 9}Ce{sub 2}Ti{sub 12}O{sub 36} ceramic filled polyethylene and epoxy composites were prepared using hot blending and mechanical mixing, respectively. 40 vol % ceramic loaded polyethylene has relative permittivity of 12.1 and loss tangent of 0.004 at 8 GHz, whereas the corresponding composite using epoxy as matrix has permittivity and loss tangent of 14.1 and 0.022, respectively. The effective medium theory fits relatively well for the observed permittivity of these composites.

Dielectric behavior of AC aged polyethylene in humid environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarpa, P.C.N.; Das-Gupta, D.K.; Bulinski, A.T.

1996-12-31

The present paper reports the results of a study of electrical aging of low density polyethylene (LDPE) aged in humid environment (0.1M NaCl) at an AC stress of 6kV/mm, 1kHz, at room temperature (RT) and at 65 C, and cross-linked polyethylene (XLPE) AC aged in humid environment (water) at an AC stress of 6kV/mm, 50Hz, at RT, for an extended period of time. For this study the dielectric spectroscopy data in the frequency range of 10{sup {minus}5}Hz to 10{sup 6}Hz and their comparative analysis, have been used to provide electrical analog models of the aging.

Polyethylene Based Materials for Biofilm Carriers Used in Wastewater Treatment

NASA Astrophysics Data System (ADS)

Moga, I. C.; Iordache, O. I.; Petrescu, G.; Pricop, F.; Dumitrescu, I.

2018-06-01

The moving bed biofilm technology is based on biofilm carriers on which consortia of microorganisms attach, develop and grow. Around the world are known many biofilm carrier variants made of varied materials. The most common materials are based on polyethylene since this material has a close to water density. The authors propose a novel biofilm carrier to be used in tertiary treatment for tannery and paper-mill wastewaters. The biological treatment is based on fungal activity. The selected fungal strains will be grown on innovative polyethylene carriers containing cellulose. The carrier will be designed to be exploited in a moving bed bioreactor and to favour fungal growth in the presence of competing bacteria.

Description of bipolar charge transport in polyethylene using a fluid model with a constant mobility: model prediction

NASA Astrophysics Data System (ADS)

LeRoy, S.; Segur, P.; Teyssedre, G.; Laurent, C.

2004-01-01

We present a conduction model aimed at describing bipolar transport and space charge phenomena in low density polyethylene under dc stress. In the first part we recall the basic requirements for the description of charge transport and charge storage in disordered media with emphasis on the case of polyethylene. A quick review of available conduction models is presented and our approach is compared with these models. Then, the bases of the model are described and related assumptions are discussed. Finally, results on external current, trapped and free space charge distributions, field distribution and recombination rate are presented and discussed, considering a constant dc voltage, a step-increase of the voltage, and a polarization-depolarization protocol for the applied voltage. It is shown that the model is able to describe the general features reported for external current, electroluminescence and charge distribution in polyethylene.

Additives aided composting of green waste: effects on organic matter degradation, compost maturity, and quality of the finished compost.

PubMed

Gabhane, Jagdish; William, S P M Prince; Bidyadhar, Rajnikant; Bhilawe, Priya; Anand, Duraisamy; Vaidya, Atul N; Wate, Satish R

2012-06-01

The effect of various additives such as fly ash, phosphogypsum, jaggery, lime, and polyethylene glycol on green waste composting was investigated through assessing their influence on microbial growth, enzymatic activities, organic matter degradation, bulk density, quality of finished compost including gradation test, heavy metal analysis, etc. A perusal of results showed that addition of jaggery and polyethylene glycol were helpful to facilitate composting process as they significantly influenced the growth of microbes and cellulase activity. The quality of finished compost prepared from jaggery and polyethylene glycol added treatments were superior to other composts, wherein reduction in C/N ratio was more than 8% in jaggery treatment. All other parameters of compost quality including gradation test also favored jaggery and polyethylene glycol as the best additives for green waste composting. Copyright © 2012 Elsevier Ltd. All rights reserved.

Vacuum-processed polyethylene as a dielectric for low operating voltage organic field effect transistors

PubMed Central

Kanbur, Yasin; Irimia-Vladu, Mihai; Głowacki, Eric D.; Voss, Gundula; Baumgartner, Melanie; Schwabegger, Günther; Leonat, Lucia; Ullah, Mujeeb; Sarica, Hizir; Erten-Ela, Sule; Schwödiauer, Reinhard; Sitter, Helmut; Küçükyavuz, Zuhal; Bauer, Siegfried; Sariciftci, Niyazi Serdar

2012-01-01

We report on the fabrication and performance of vacuum-processed organic field effect transistors utilizing evaporated low-density polyethylene (LD-PE) as a dielectric layer. With C60 as the organic semiconductor, we demonstrate low operating voltage transistors with field effect mobilities in excess of 4 cm2/Vs. Devices with pentacene showed a mobility of 0.16 cm2/Vs. Devices using tyrian Purple as semiconductor show low-voltage ambipolar operation with equal electron and hole mobilities of ∼0.3 cm2/Vs. These devices demonstrate low hysteresis and operational stability over at least several months. Grazing-angle infrared spectroscopy of evaporated thin films shows that the structure of the polyethylene is similar to solution-cast films. We report also on the morphological and dielectric properties of these films. Our experiments demonstrate that polyethylene is a stable dielectric supporting both hole and electron channels. PMID:23483783

Renewable hydrocarbons for jet fuels from biomass and plastics via microwave-induced pyrolysis and hydrogenation processes

NASA Astrophysics Data System (ADS)

Zhang, Xuesong

This dissertation aims to enhance the production of aromatic hydrocarbons in the catalytic microwave-induced pyrolysis, and maximize the production of renewable cycloalkanes for jet fuels in the hydrogenation process. In the process, ZSM-5 catalyst as the highly efficient catalyst was employed for catalyzing the pyrolytic volatiles from thermal decomposition of cellulose (a model compound of lignocellulosic biomass). A central composite experiment design (CCD) was used to optimize the product yields as a function of independent factors (e.g. catalytic temperature and catalyst to feed mass ratio). The low-density polyethylene (a mode compound of waste plastics) was then carried out in the catalytic microwave-induced pyrolysis in the presence of ZSM-5 catalyst. Thereafter, the catalytic microwave-induced co-pyrolysis of cellulose with low-density polyethylene (LDPE) was conducted over ZSM-5 catalyst. The results showed that the production of aromatic hydrocarbons was significantly enhanced and the coke formation was also considerably reduced comparing with the catalytic microwave pyrolysis of cellulose or LDPE alone. Moreover, practical lignocellulosic biomass (Douglas fir sawdust pellets) was converted into aromatics-enriched bio-oil by catalytic microwave pyrolysis. The bio-oil was subsequently hydrogenated by using the Raney Ni catalyst. A liquid-liquid extraction step was implemented to recover the liquid organics and remove the water content. Over 20% carbon yield of liquid product regarding lignocellulosic biomass was obtained. Up to 90% selectivity in the liquid product belongs to jet fuel range cycloalkanes. As the integrated processes was developed, catalytic microwave pyrolysis of cellulose with LDPE was conducted to improve aromatic production. After the liquid-liquid extraction by the optimal solvent (n-heptane), over 40% carbon yield of hydrogenated organics based on cellulose and LDPE were achieved in the hydrogenation process. As such, real lignocellulosic biomass with LDPE were transformed into aromatics via co-feed catalytic microwave pyrolysis. It was also found that close to 40% carbon yield of hydrogenated organics were garnered. Based on these outcomes, the reaction kinetics regarding non-catalytic co-pyrolysis and catalytic co-pyrolysis of biomass with plastics were also presented. In addition, the techno-economic analysis of the catalytically integrated processes from lignocellulosic biomass to renewable cycloalkanes for jet fuels was evaluated in the dissertation as well.

Recovery of monomers from recycled plastics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharp, L.L.; Ness, R.O. Jr.; Sosa, J.M.

1995-10-01

Plastics make up approximately 20% by volume of the material disposed of in landfills in the United States. The increased interest in recycling has focused attention on ways to expand our current recycling efforts. Types of commodity plastics typically found in a postconsumer stream include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polystyrene (PS). In addition to plastics such as these, a number of organic and inorganic constituents will be present, including paper, paint, food, and various metals. These constituents are present as a result of introduction intomore » the plastics during manufacturing (to give a plastic product selective properties) or as residual matter from use by the consumer. The Energy & Environmental Research Center (EERC) is one of several groups in the United States and Europe that, over the last several years, has worked toward developing a process to thermally break down postconsumer plastics to hydrocarbon liquids and gases. Such a process, sometimes referred to as thermal depolymerization, thermal recycling, or feedstock recycling, produces hydrocarbon liquids and gases that could be used for the manufacture of new plastics or other petroleum products. The specific slate of products depends on processing conditions. Subsequent studies have identified several relatively high-value products possible from the process, including ethylene (C{sub 2}{sup -}), propylene (C{sub 3}{sup -}), and butylenes. Past work at the EERC has also indicated that optimal processing conditions exist for these olefin yields. The proposed the EPA work is based on information, presented here, that was obtained in studies completed at the EERC under the sponsorship of the American Plastics Council (APC) and the U.S. Department of Energy (DOE).« less

High-density polyethylene (HDPE)-degrading potential bacteria from marine ecosystem of Gulf of Mannar, India.

PubMed

Balasubramanian, V; Natarajan, K; Hemambika, B; Ramesh, N; Sumathi, C S; Kottaimuthu, R; Rajesh Kannan, V

2010-08-01

Assessment of high-density polyethylene (HDPE)-degrading bacteria isolated from plastic waste dumpsites of Gulf of Mannar. Rationally, 15 bacteria (GMB1-GMB15) were isolated by enrichment technique. GMB5 and GMB7 were selected for further studies based on their efficiency to degrade the HDPE and identified as Arthrobacter sp. and Pseudomonas sp., respectively. Assessed weight loss of HDPE after 30 days of incubation was nearly 12% for Arthrobacter sp. and 15% for Pseudomonas sp. The bacterial adhesion to hydrocarbon (BATH) assay showed that the cell surface hydrophobicity of Pseudomonas sp. was higher than Arthrobacter sp. Both fluorescein diacetate hydrolysis and protein content of the biofilm were used to test the viability and protein density of the biomass. Acute peak elevation was observed between 2 and 5 days of inoculation for both bacteria. Fourier transform infrared (FT-IR) spectrum showed that keto carbonyl bond index (KCBI), Ester carbonyl bond index (ECBI) and Vinyl bond index (VBI) were increased indicating changes in functional group(s) and/or side chain modification confirming the biodegradation. The results pose us to suggest that both Pseudomonas sp. and Arthrobacter sp. were proven efficient to degrade HDPE, albeit the former was more efficacious, yet the ability of latter cannot be neglected. Recent alarm on ecological threats to marine system is dumping plastic waste in the marine ecosystem and coastal arena by anthropogenic activity. In maintenance phase of the plastic-derived polyethylene waste, the microbial degradation plays a major role; the information accomplished in this work will be the initiating point for the degradation of polyethylene by indigenous bacterial population in the marine ecosystem and provides a novel eco-friendly solution in eco-management.

Degradation assessment of natural weathering on low density polyethylene/thermoplastic soya spent powder blends

NASA Astrophysics Data System (ADS)

Nuradibah, M. A.; Sam, S. T.; Noriman, N. Z.; Ragunathan, S.; Ismail, H.

2015-07-01

Soya spent powder was blended with low density polyethylene (LDPE) ranging from 5-25 wt%. Glycerol was added to soya spent powder (SSP) for preparation of thermoplastic soya spent powder (TSSP). Then, the blends were exposed to natural weathering for 6 months. The susceptibility of the LDPE/soya spent powder blends based on its tensile, morphological properties and structural changes was measured every three months. The tensile strength of LDPE/TSSP blends after 6 months of weathering was the lowest compared to the other blends whereas LDPE/SSP blends after 6 months of weathering demonstrated the lowest elongation at break (Eb). Large pore can be seen on the surface of 25 wt% of LDPE/SSP blends.

Vacuum Outgassing of High Density Polyethylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dinh, L N; Sze, J; Schildbach, M A

A combination of thermogravimetric analysis (TGA) and temperature programmed decomposition (TPD) was employed to identify the outgassing species, the total amount of outgassing, and the outgassing kinetics of high density polyethylene (HDPE) in a vacuum environment. The isoconversional kinetic analysis was then used to analyze the outgassing kinetics and to predict the long-term outgassing of HDPE in vacuum applications at ambient temperature. H{sub 2}O and C{sub n}H{sub x} with n as high as 9 and x centering around 2n are the major outgassing species from solid HDPE, but the quantities evolved can be significantly reduced by vacuum baking at 368more » K for a few hours prior to device assembly.« less

Mechanical and morphological study of linear low density polyethylene (LLDPE)/cyperus odoratus (CY) biocomposites

NASA Astrophysics Data System (ADS)

Faris, N. A.; Noriman, N. Z.; Haron, Adli; Sam, S. T.; Hamzah, R.; Shayfull, Z.; Ghazali, M. F.

2017-09-01

The potential of Cyperus Odoratus (CY) as a filler was studied. The CY, in a powder form, was mixed with Linear Low Density Polyethylene (LLDPE), prior to being fed into a twin screw extruder and subsequently into an injection moulding machine to produce LLDPY/CY biocomposites. The Scanning Electron Microscope (SEM) was utilized and tensile tests were performed on the test specimens to characterize the structure and properties of the composites. The integration of CY powder and LLDPE resulted in an increment of the modulus of elasticity, but a reduction in tensile strength and elongation at break. The morphology characterization of these composites, determined through the SEM, showed poor interfacial adhesion between the filler and the thermoplastic LLDPE matrix.

Application of support vector regression for optimization of vibration flow field of high-density polyethylene melts characterized by small angle light scattering

NASA Astrophysics Data System (ADS)

Xian, Guangming

2018-03-01

In this paper, the vibration flow field parameters of polymer melts in a visual slit die are optimized by using intelligent algorithm. Experimental small angle light scattering (SALS) patterns are shown to characterize the processing process. In order to capture the scattered light, a polarizer and an analyzer are placed before and after the polymer melts. The results reported in this study are obtained using high-density polyethylene (HDPE) with rotation speed at 28 rpm. In addition, support vector regression (SVR) analytical method is introduced for optimization the parameters of vibration flow field. This work establishes the general applicability of SVR for predicting the optimal parameters of vibration flow field.

Investigation of compression behavior of PE/EVA foam injection molded parts

NASA Astrophysics Data System (ADS)

Spina, Roberto

2017-10-01

The main objective of the presented work is to evaluate the compression behavior of a polymeric foam blend by using a robust framework for the testing sequence of foaming injection molded parts, with the aim of establishing a standard testing cycle for the evaluation of new matrix material. The research purpose is to assess parameters influencing compression behavior and give useful suggestions for the implementation of a finite element analysis. The polymeric blend consisted of a mixture of low density polyethylenes (LDPEs), a high-density polyethylene (HDPE), an ethylene-vinyl acetate (EVA) and an azodicarbonamide (ADC). The thermal, rheological and compression properties of the blend are fully described, as well as the injection molding process for two specimen types.

EVALUATION OF ULTRASONIC PHASED-ARRAY FOR DETECTION OF PLANAR FLAWS IN HIGH-DENSITY POLYETHYLENE (HDPE) BUTT-FUSION JOINTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prowant, Matthew S.; Denslow, Kayte M.; Moran, Traci L.

2016-09-21

The desire to use high-density polyethylene (HDPE) piping in buried Class 3 service and cooling water systems in nuclear power plants is primarily motivated by the material’s high resistance to corrosion relative to that of steel and metal alloys. The rules for construction of Class 3 HDPE pressure piping systems were originally published in Code Case N-755 and were recently incorporated into the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME BPVC) Section III as Mandatory Appendix XXVI (2015 Edition). The requirements for HDPE examination are guided by criteria developed for metal pipe and are based onmore » industry-led HDPE research or conservative calculations.« less

Thermal properties of silica-filled high density polyethylene composites compatibilized with glut palmitate

NASA Astrophysics Data System (ADS)

Samsudin, Dalina; Ismail, Hanafi; Othman, Nadras; Hamid, Zuratul Ain Abdul

2017-07-01

A study of thermal properties resulting from the utilization of Glut Palmitate (GP) on the silica filled high density polyethylene (HDPE) composites was carried out. The composites with the incorporation of GP at 0.5, 1.0, 2.0 and 3.0 phr were prepared by using an internal mixer at the temperature 180 °C and the rotor speed of 50 rpm. The thermal behaviours of the composites were then investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was found that the crystallinity and the thermal stability of the composites increased with the incorporation of GP. The highest crystallinity contents and decomposition temperatures were observed at the 1 phr GP loading.

Numerical-experimental investigation of PE/EVA foam injection molded parts

NASA Astrophysics Data System (ADS)

Spina, Roberto

The main objective of the presented work is to propose a robust framework to test foaming injection molded parts, with the aim of establishing a standard testing cycle for the evaluation of a new foam material based on numerical and experimental results. The research purpose is to assess parameters influencing several aspects, such as foam morphology and compression behavior, using useful suggestions from finite element analysis. The investigated polymeric blend consisted of a mixture of low density polyethylenes (LDPEs), a high-density polyethylene (HDPE), an ethylene-vinyl acetate (EVA) and an azodicarbonamide (ADC). The thermal, rheological and compression properties of the blend are fully described, as well as the numerical models and the parameters of the injection molding process.

Nanocomposites of high-density polyethylene with amorphous calcium phosphate: in vitro biomineralization and cytocompatibility of human mesenchymal stem cells.

PubMed

Hild, Nora; Fuhrer, Roland; Mohn, Dirk; Bubenhofer, Stephanie B; Grass, Robert N; Luechinger, Norman A; Feldman, Kirill; Dora, Claudio; Stark, Wendelin J

2012-10-01

Polyethylene is widely used as a component of implants in medicine. Composites made of high-density polyethylene (HDPE) containing different amounts of amorphous calcium phosphate nanoparticles were investigated concerning their in vitro biomedical performance. The nanoparticles were produced by flame spray synthesis and extruded with HDPE, the latter complying with Food and Drug Administration regulations. Mechanical properties such as Young's modulus and contact angle as well as in vitro biomineralization of the nanocomposites hot-pressed into thin films were evaluated. The deposition of a hydroxyapatite layer occurred upon immersion in simulated body fluid. Additionally, a cell culture study with human mesenchymal stem cells for six weeks allowed a primary assessment of the cytocompatibility. Viability assays (alamarBlue and lactate dehydrogenase detection) proved the absence of cytotoxic effects of the scaffolds. Microscopic images after hematoxylin and eosin staining confirmed typical growth and morphology. A preliminary experiment analyzed the alkaline phosphatase activity after two weeks. These findings motivate further investigations on bioactive HDPE in bone tissue engineering.

Enhancing Degradation of Low Density Polyethylene Films by Curvularia lunata SG1 Using Particle Swarm Optimization Strategy.

PubMed

Raut, Sangeeta; Raut, Smita; Sharma, Manisha; Srivastav, Chaitanya; Adhikari, Basudam; Sen, Sudip Kumar

2015-09-01

In the present study, artificial neural network (ANN) modelling coupled with particle swarm optimization (PSO) algorithm was used to optimize the process variables for enhanced low density polyethylene (LDPE) degradation by Curvularia lunata SG1. In the non-linear ANN model, temperature, pH, contact time and agitation were used as input variables and polyethylene bio-degradation as the output variable. Further, on application of PSO to the ANN model, the optimum values of the process parameters were as follows: pH = 7.6, temperature = 37.97 °C, agitation rate = 190.48 rpm and incubation time = 261.95 days. A comparison between the model results and experimental data gave a high correlation coefficient ([Formula: see text]). Significant enhancement of LDPE bio-degradation using C. lunata SG1by about 48 % was achieved under optimum conditions. Thus, the novelty of the work lies in the application of combination of ANN-PSO as optimization strategy to enhance the bio-degradation of LDPE.

Stability of color in Spanish-style green table olives pasteurized and stored in plastic containers.

PubMed

Sánchez, Antonio Higinio; López-López, Antonio; Beato, Víctor Manuel; de Castro, Antonio; Montaño, Alfredo

2017-08-01

There is an increasing interest in the use of pasteurizable plastic packaging by the olive industry. In order to investigate the change from traditional glass or varnished can containers to plastic packaging, the proper plastic material that is compatible with fermented olives while maintaining color quality during pasteurization treatment and storage must be selected. This work is focused on color stability in two distinct pasteurizable plastic containers with different oxygen permeability. In PET + MDPE/EVOH (polyethylene terephthalate + medium-density polyethylene/ethylene vinyl alcohol) pouches, pasteurization provoked severe browning which drastically decreased their color shelf life (<6 weeks). However, this browning did not occur in the unpasteurized product without preservatives owing to the presence of microorganisms. In AlOx-coated PET + MDPE (aluminum oxide coating on polyethylene terephthalate + medium-density polyethylene) pouches, color changes were small or negligible throughout storage, especially if ascorbic acid was added to the packing solution (shelf life > 6.5 months). The plastic material had a significant effect on the retention of color of the pasteurized product. The use of AlOx-coated PET + MDPE pouches could be an alternative to traditional packaging for the pasteurization and storage of Spanish-style green olives from a color quality standpoint. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

The effect of polyethylene glycol on the characteristics of kenaf cellulose/low-density polyethylene biocomposites.

PubMed

Tajeddin, Behjat; Rahman, Russly Abdul; Abdulah, Luqman Chuah

2010-08-01

Toward the development of biocomposites for packaging applications, the possibility of using kenaf cellulose (KC) was investigated in the production of low-density polyethylene (LDPE)/KC/polyethylene glycol (PEG) biocomposites. First, cellulose was extracted from the cell walls of kenaf-bast fibers. Then, different weights of LDPE, KC, and PEG were blended, and the effects of varying the concentrations of KC and PEG on the synthesis process were evaluated, and the resulting composites were characterized with respect to their mechanical, thermal, biodegradability and water-absorption properties. A scanning electron microscope (SEM) was also used to observe the surface morphology of the samples before and after biodegradation tests. The results showed that the mechanical properties of the biocomposites decreased slightly as the KC content was increased from 0 to 50wt% in the biocomposite formulation; however, there was a good homogeneity between samples with added PEG. The addition of KC improved the thermal resistance of these biocomposites; PEG also had positive role in the thermal behavior of the composites. Based on a soil-burial test, the biodegradability of the composites showed a clear trend of increase degradation with increasing KC content in the formulation. While water-absorption values for the composites were higher than that of pure LDPE polymer, the addition of PEG to the formulation reduced the water absorption of the composites. Copyright 2010 Elsevier B.V. All rights reserved.

Mechanical, Rheological, and Bioactivity Properties of Ultra High-Molecular-Weight Polyethylene Bioactive Composites Containing Polyethylene Glycol and Hydroxyapatite

PubMed Central

Ahmad, Mazatusziha; Wahit, Mat Uzir; Abdul Kadir, Mohammed Rafiq; Mohd Dahlan, Khairul Zaman

2012-01-01

Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis. PMID:22666129

Effect of biobased fillers nature on biodeterioration of hybrid polyethylene composites by mold fungi

NASA Astrophysics Data System (ADS)

Mastalygina, E. E.; Popov, A. A.; Pantyukhov, P. V.

2017-06-01

The paper is devoted to investigation of deterioration of natural fillers and polyethylene composites on their basis (polyethylene/filler=70/30) due to the action of mold fungi. The fillers chemical composition, dimensional parameters and biodegradability have been analyzed as factors exert a considerable impact on composite materials biodeterioration. It has been found that the principal factor determining the biodeterioration of polyethylene/filler composites by mold fungi is chemical composition of a filler and, in turn, its biodegradability. The excess of holocellulose content over lignin content and high protein content in a filler are able to induce biofouling of the polymeric composite materials. The presence of soluble and easy hydrolysed fraction in a filler increases its availability in a polymeric matrix. According to the study results, most effective natural fillers as additives stimulating polyethylene composites biodegradability are milled straw of seed flax and hydrolyzed keratin of bird’s feather.

A comparison of the efficacy of various antioxidants on the oxidative stability of irradiated polyethylene.

PubMed

Hope, Natalie; Bellare, Anuj

2015-03-01

Ultrahigh-molecular-weight polyethylene (UHMWPE) is subjected to radiation crosslinking to form highly crosslinked polyethylene (HXLPE), which has improved wear resistance. First-generation HXLPE was subjected to thermal treatment to reduce or quench free radicals that can induce long-term oxidative degeneration. Most recently, antioxidants have been added to HXLPE to induce oxidative resistance rather than by thermal treatment. However, antioxidants can interfere with the efficiency of radiation crosslinking. We sought to identify (1) which antioxidant from among those tested (vitamin E, β-carotene, butylated hydroxytoluene, or pentaerythritol tetrakis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]) causes the least reduction of crosslinking; (2) which promotes the greatest oxidative stability; and (3) which had the lowest ratio of oxidation index to crosslink density. Medical-grade polyethylene (PE) resin was blended with 0.1 weight % of the following stabilizers: alpha tocopherol (vitamin E), β-carotene, butylated hydroxytoluene (BHT), and pentaerythritol tetrakis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (a hindered phenol antioxidant [HPAO]). These blends were compression-molded into sheets and subjected to electron beam irradiation to a dose of 100 kGy. Equilibrium swelling experiments were conducted to calculate crosslink density. Each PE was subjected to accelerated aging for a period of 2 weeks and Fourier transform infrared spectroscopy was used to measure the maximum oxidation. Statistical analysis was conducted using analysis of variance with Fisher's protected least significant difference in which a p value of < 0.05 was used to define a significant difference. The least reduction of crosslinking in antioxidant-containing HXLPE was observed with HPAO, which had a crosslink density (n = 6) of 0.167 (effect size [ES] = 0.87; 95% confidence interval [CI], 0.162-0.173) mol/dm(3) compared with 0.139 (ES = 1.57; 95% CI, 0.132-0.146) mol/dm(3) (p = 0.020) for BHT, 0.131 (ES = 1.77; 95% CI, 0.123-0.139) mol/dm(3) (p = 0.004) for β-carotene, and 0.130 (ES = 1.79; 95% CI, 0.124-0.136) mol/dm(3) (p = 0.003) for vitamin E, whereas pure HXLPE had a crosslink density of 0.203 (95% CI, 0.170-0.235) mol/dm(3) (p = 0.005). BHT-PE had an oxidation index of 0.21 (ES = 13.14; 95% CI, 0.19-0.22) followed by HPAO-PE, vitamin E-PE and β-carotene-PE, which had oxidation indices of 0.28 (ES = 9.68; 95% CI, 0.28-0.29), 0.29 (ES = 9.59; 95% CI, 0.27-0.30), and 0.35 (ES = 6.68; 95% CI, 0.34-0.37), respectively (p < 0.001 for all groups). BHT-PE had the lowest ratio of oxidation index to crosslink density of the materials tested (1.49, ES = 1.94; 95% CI, 1.32-1.66) followed by HPAO-PE (1.70, ES = 1.52; 95% CI, 1.61-1.80), vitamin E-PE (2.21, ES = 0.52; 95% CI, 2.05-2.38), and β-carotene-PE (2.69, ES = -0.43; 95% CI, 2.46-2.93) compared with control PE (2.47, 95% CI, 2.07-2.88) with β-carotene (p = 0.208) and vitamin E (p = 0.129) not being different from the control. BHT-modified HXLPE was found in this study to have the lowest oxidation index as well as the lowest ratio of oxidation index to crosslink density compared with vitamin E, HPAO, and β-carotene-modified HXLPEs. More comprehensive studies are required such as wear testing using joint simulators as well as biocompatibility studies before BHT-modified HXLPE can be considered for clinical use. BHT is a synthetic antioxidant commonly used in the polymer industry to prevent long-term oxidative degradation and has been approved by the FDA for use in cosmetics and foodstuffs. It may be an attractive potential stabilizer for HXLPE in total joint replacements.

Biodegradation of Low-Density Polyethylene (LDPE) by Mixed Culture of Lysinibacillus xylanilyticus and Aspergillus niger in Soil

PubMed Central

Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

2013-01-01

In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE) were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR), x-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source. PMID:24086254

Biodegradation of low-density polyethylene (LDPE) by mixed culture of Lysinibacillus xylanilyticus and Aspergillus niger in soil.

PubMed

Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

2013-01-01

In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE) were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR), x-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source.

NASA, We Have a Challenge and It's Food Packaging

NASA Technical Reports Server (NTRS)

Perchonok, Michele

2014-01-01

Current Packaging: Freeze Dried Foods Packaging ? The thermoformed base is fabricated from Combitherm PAXX230 [a coextrusion of nylon/medium-density polyethylene (MDPE)/nylon/ethylene-vinyl alcohol (EVOH)/nylon/MDPE/linear low-density polyethylene (LLDPE)]. ? The lid is fabricated from Combitherm PAXX115 (a coextrusion of nylon/EVOH/nylon/LF adhesive/HV polyethylene/LLDPE) ? Natural form (Bite size) foods ? The bite-size food package is fabricated from Combitherm PAXX115, a coextrusion of nylon/EVOH/nylon/LF adhesive/HV polyethylene/LLDPE. ? Overwrap ? Packages are wrapped in a white pouch,.003-mm thick, fabricated from a laminate of polyester/polyethylene/aluminum foil/Surlyn®. This overwrap is removed before the food is prepared and heated. Requirements ? High barrier packaging - low oxygen and water vapor transmission rates ? No aluminum layer ? Mass - <145 grams per m2 ? Flexible ? Puncture resistant ? Approved for food use ? Amenable to sterilization ? Able to be heat sealed ? Preferred (not required) ? Transparent ? Retortable, microwavable, high pressure use. Small Business Innovative Research Program - 7 years ? 8 Phase I contracts ? 4 Phase II contracts ? Two workshops to bring together food packaging experts ? Three internal research tasks ? Public Outreach - average of 3 presentations/yr. for 8 years describing NASA's challenges ? Department of Defense Collaboration - Combat Feeding Program No significant improvement in food packaging capabilities after these efforts. It was unlikely that a food packaging solution could be found within the food science community ? There was a need to go outside to other industries such as pharmaceutical or electrical ? Although a positive result was preferred, a negative result would also be useful ? Two Innovation Techniques were used as a comparison ? InnoCentive - Theoretical Challenge to identify new technologies ? Yet2.com - A matchmaker between NASA and commercial packaging manufacturers

Micro X-Ray Computed Tomography Mass Loss Assessment of Different UHMWPE: A Hip Joint Simulator Study on Standard vs. Cross-Linked Polyethylene

PubMed Central

Zanini, Filippo; Carmignato, Simone

2017-01-01

More than 60.000 hip arthroplasty are performed every year in Italy. Although Ultra-High-Molecular-Weight-Polyethylene remains the most used material as acetabular cup, wear of this material induces over time in vivo a foreign-body response and consequently osteolysis, pain, and the need of implant revision. Furthermore, oxidative wear of the polyethylene provoke several and severe failures. To solve these problems, highly cross-linked polyethylene and Vitamin-E-stabilized polyethylene were introduced in the last years. In in vitro experiments, various efforts have been made to compare the wear behavior of standard PE and vitamin-E infused liners. In this study we compared the in vitro wear behavior of two different configurations of cross-linked polyethylene (with and without the add of Vitamin E) vs. the standard polyethylene acetabular cups. The aim of the present study was to validate a micro X-ray computed tomography technique to assess the wear of different commercially available, polyethylene’s acetabular cups after wear simulation; in particular, the gravimetric method was used to provide reference wear values. The agreement between the two methods is documented in this paper. PMID:28107468

Effect of Ar ion on the surface properties of low density polyethylene.

PubMed

Zaki, M F

2016-04-15

In this paper, low-density polyethylene (LDPE) was irradiated by argon ion with different fluences up to 10(15) ions/cm(2). The optical, chemical and hardness properties have been investigated using UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and micro-indentation tester, respectively. The results showed the ion beam bombardment induced decreases in the transmittance of the irradiated polymer samples. This change in transmittance can be attributed to the formation of conjugated bonds i.e. possible formation of defects and/or carbon clusters. The indirect optical band gap decreased from 3.0 eV for the pristine sample to 2.3 eV for that sample irradiated with the highest fluence of the Ar ion beam. Furthermore, the number of carbon atoms and clusters increased with increasing Ar ion fluences. FTIR spectra showed the formation of new bands of the bombarded polymer samples. Furthermore, polar groups were created on the surface of the irradiated samples which refer to the increase of the hydrophilic nature of the surface of the irradiated samples. The Vicker's hardness increased from 4.9 MPa for the pristine sample to 17.9 MPa for those bombarded at the highest fluence. This increase is attributed to the increase in the crosslinking and alterations of the bombarded surface into hydrogenated amorphous carbon, which improves the hardness of the irradiated samples. The bombarded LDPE surfaces may be used in special applications to the field of the micro-electronic devices and shock absorbers. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydrolytically Degradable Poly(Ethylene Glycol) Hydrogel Scaffolds as a Cell Delivery Vehicle: Characterization of PC12 Cell Response

PubMed Central

Zustiak, Silviya P.; Pubill, Stephanie; Ribeiro, Andreia; Leach, Jennie B.

2013-01-01

The central nervous system (CNS) has a low intrinsic potential for regeneration following injury and disease, yet neural stem/progenitor cell (NPC) transplants show promise to provide a dynamic therapeutic in this complex tissue environment. Moreover, biomaterial scaffolds may improve the success of NPC-based therapeutics by promoting cell viability and guiding cell response. We hypothesized that a hydrogel scaffold could provide a temporary neurogenic environment that supports cell survival during encapsulation, and degrades completely in a temporally controlled manner to allow progression of dynamic cellular processes such as neurite extension. We utilized PC12 cells as a model cell line with an inducible neuronal phenotype to define key properties of hydrolytically-degradable poly(ethylene glycol) hydrogel scaffolds that impact cell viability and differentiation following release from the degraded hydrogel. Adhesive peptide ligands (RGDS, IKVAV or YIGSR), were required to maintain cell viability during encapsulation; as compared to YIGSR, the RGDS and IKVAV ligands were associated with a higher percentage of PC12 cells that differentiated to the neuronal phenotype following release from the hydrogel. Moreover, among the hydrogel properties examined (e.g., ligand type, concentration), total polymer density within the hydrogel had the most prominent effect on cell viability, with densities above 15% w/v leading to decreased cell viability likely due to a higher shear modulus. Thus, by identifying key properties of degradable hydrogels that affect cell viability and differentiation following release from the hydrogel, we lay the foundation for application of this system towards future applications of the scaffold as a neural cell delivery vehicle. PMID:24474590

Ultrasonic wave velocity measurement in small polymeric and cortical bone specimens

NASA Technical Reports Server (NTRS)

Kohles, S. S.; Bowers, J. R.; Vailas, A. C.; Vanderby, R. Jr

1997-01-01

A system was refined for the determination of the bulk ultrasonic wave propagation velocity in small cortical bone specimens. Longitudinal and shear wave propagations were measured using ceramic, piezoelectric 20 and 5 MHz transducers, respectively. Results of the pulse transmission technique were refined via the measurement of the system delay time. The precision and accuracy of the system were quantified using small specimens of polyoxymethylene, polystyrene-butadiene, and high-density polyethylene. These polymeric materials had known acoustic properties, similarity of propagation velocities to cortical bone, and minimal sample inhomogeneity. Dependence of longitudinal and transverse specimen dimensions upon propagation times was quantified. To confirm the consistency of longitudinal wave propagation in small cortical bone specimens (< 1.0 mm), cut-down specimens were prepared from a normal rat femur. Finally, cortical samples were prepared from each of ten normal rat femora, and Young's moduli (Eii), shear moduli (Gij), and Poisson ratios (Vij) were measured. For all specimens (bone, polyoxymethylene, polystyrene-butadiene, and high-density polyethylene), strong linear correlations (R2 > 0.997) were maintained between propagation time and distance throughout the size ranges down to less than 0.4 mm. Results for polyoxymethylene, polystyrene-butadiene, and high-density polyethylene were accurate to within 5 percent of reported literature values. Measurement repeatability (precision) improved with an increase in the wave transmission distance (propagating dimension). No statistically significant effect due to the transverse dimension was detected.

Design of a Papain Immobilized Antimicrobial Food Package with Curcumin as a Crosslinker

PubMed Central

Sivakumar, Ponnurengam Malliappan; Doble, Mukesh

2015-01-01

Contamination of food products by spoilage and pathogenic microorganisms during post process handling is one of the major causes for food spoilage and food borne illnesses. The present green sustainable approach describes the covalent immobilization of papain to LDPE (low density polyethylene), HDPE (high density polyethylene), LLDPE (linear low density polyethylene) and PCL (polycaprolactam) with curcumin as the photocrosslinker. About 50% of curcumin and 82-92% of papain were successfully immobilized on these polymers. After 30 days, the free enzyme retained 87% of its original activity, while the immobilized enzyme retained more than 90% of its activity on these polymers. Papain crosslinked to LLDPE exhibited the best antibiofilm properties against Acinetobacter sp. KC119137.1 and Staphylococcus aureus NCIM 5021 when compared to the other three polymers, because of the highest amount of enzyme immobilized on this surface. Papain acts by damaging the cell membrane. The enzyme is able to reduce the amount of carbohydrate and protein contents in the biofilms formed by these organisms. Meat wrapped with the modified LDPE and stored at 4°C showed 9 log reduction of these organisms at the end of the seventh day when compared to samples wrapped with the bare polymer. This method of crosslinking can be used on polymers with or without functional groups and can be adopted to bind any type of antimicrobial agent. PMID:25906061

Liquid Viscosity and Density Measurement with Flexural-Plate-Wave Sensors

DTIC Science & Technology

1996-04-01

capillary-viscometer-measured viscosity in Fig. 4. "The data from solutions of poly(ethylene glycol), having average molecular weights 3350 and 15,000...have seen similar results for the FPW-measured viscosity of salmon-sperm DNA solutions. 25 glycerol WA " PEG 3,350 H-4 . e! 2 PEG 15,000 IK- ,,,," HEC...number of aqueous solutions of the polymers poly(ethylene glycol) ( PEG ) and hydroxyethyl cellulose (HEC). The response of the FPW sensor (vertical axis

40 CFR 52.1670 - Identification of plans.

Code of Federal Regulations, 2010 CFR

2010-07-01

... provides for adequate State legal authority to ensure for public availability of air pollutant emission..., and April 3, 1987, concerning the manufacture of high-density polyethylene, polypropylene, and...

Bone remodelling around HA-coated acetabular cups

PubMed Central

Nielsen, P. T.; Søballe, K.

2006-01-01

This study was designed to investigate bone remodelling around the cup in cementless THA. Previous studies indicate an advantage of better sealing of the bone-prosthesis interface by HA/TCP coating of implants, inhibiting polyethylene-induced osteolysis. One hundred patients gave informed consent to participate in a controlled randomized study between porous coated Trilogy versus Trilogy Calcicoat (HA/TCP coated). The cup was inserted in press-fit fixation. The femoral component was a cementless porous coated titanium alloy stem (Bi-Metric), with a modular 28-mm CrCo head. The Harris Hip Score (HHS) and bone mineral density (BMD) determined by DEXA scanning were used to study the effect. Measurements revealed no difference between the two groups after 3 years either in the clinical outcome or in terms of periprosthetic bone density. Patients with a body mass index above normal regained more bone mineral than patients with normal weight. This finding supports the assumption that load is beneficial to bone remodelling. PMID:16761153

Wear Behaviours and Oxidation Effects on Different UHMWPE Acetabular Cups Using a Hip Joint Simulator

PubMed Central

Jaber, Sami Abdel; Merola, Massimiliano

2018-01-01

Given the long-term problem of polyethylene wear, medical interest in the new improved cross-linked polyethylene (XLPE), with or without the adding of vitamin E, has risen. The main aim of this study is to gain further insights into the mutual effects of radiation cross-linking and addition of vitamin E on the wear performance of ultra-high-molecular-weight polyethylene (UHMWPE). We tested four different batches of polyethylene (namely, a standard one, a vitamin E-stabilized, and two cross-linked) in a hip joint simulator for five million cycles where bovine calf serum was used as lubricant. The acetabular cups were then analyzed using a confocal profilometer to characterize the surface topography. Moreover; the cups were analyzed by using Fourier Transformed Infrared Spectroscopy and Differential Scanning Calorimetry in order to assess the chemical characteristics of the pristine materials. Comparing the different cups’ configuration, mass loss was found to be higher for standard polyethylene than for the other combinations. Mass loss negatively correlated to the cross-link density of the polyethylenes. None of the tested formulations showed evidence of oxidative degradation. We found no correlation between roughness parameters and wear. Furthermore, we found significantly differences in the wear behavior of all the acetabular cups. XLPEs exhibited lower weight loss, which has potential for reduced wear and decreased osteolysis. However, surface topography revealed smoother surfaces of the standard and vitamin E stabilized polyethylene than on the cross-linked samples. This observation suggests incipient crack generations on the rough and scratched surfaces of the cross-linked polyethylene liners. PMID:29547536

Effect of degrading yellow oxo-biodegradable low-density polyethylene films to water quality

NASA Astrophysics Data System (ADS)

Requejo, B. A.; Pajarito, B. B.

2017-05-01

Polyethylene (PE) contributes largely to plastic wastes that are disposed in aquatic environment as a consequence of its widespread use. In this study, yellow oxo-biodegradable low-density PE films were immersed in deionized water at 50°C for 49 days. Indicators of water quality: pH, oxidation-reduction potential, turbidity, and total dissolved solids (TDS), were monitored at regular intervals. It was observed that pH initially rises and then slowly decreases with time, oxidation-reduction potential decreases then slowly increases with time, turbidity rises above the control at varied rates, and TDS increases abruptly and rises at a hindered rate. Moreover, the films potentially leach out lead chromate. The results imply that degrading oxo-biodegradable LDPE films results to significant reduction of water quality.

Conjunctivodacryocystorhinostomy using a high-density porous polyethylene-coated tear drain tube.

PubMed

Pushker, Neelam; Khurana, Saurbhi; Shrey, Dinesh; Bajaj, Mandeep S; Chawla, Bhavna; Chandra, Mahesh

2013-08-01

To evaluate the outcome of conjunctivodacryocystorhinostomy using a high-density porous polyethylene (HDPP)-coated tear drain tube. Patients with epiphora due to a proximal lacrimal system block were included in a prospective interventional case study. A total of 22 eyes were treated with lacrimal bypass surgery using the HDPP-coated tube. On follow-up (12-41 months), 21 eyes had a patent well-positioned tube with subjective relief of epiphora. In one eye, a loose sleeve was noted during surgery. The tube dislodged postoperatively and was removed. A high success rate with only a few minor complications is achievable using a HDPP-coated tear drain tube for lacrimal bypass surgery. Long-term follow-up is required to look for tube blockage due to conjunctival or nasal mucosal overgrowth.

Tapanuli Organoclay Addition Into Linear Low Density Polyethylene-Pineapple Fiber Composites

NASA Astrophysics Data System (ADS)

Adawiyah, Robiatul; Juwono, Ariadne L.; Roseno, Seto

2010-12-01

Linear low density polyethylene-Tapanuli organoclay-pineapple fiber composites were succesfully synthesized by a melt intercalation method. The clay was modified as an organoclay by a cation exchange reaction using hexadecyl trimethyl ammonium bromide (HDTMABr) surfactant. The X-ray diffraction results of the organoclay exhibited a higher basal spacing of 1.87 nm compared to the unmodified clay of 1.46 nm. The composite tensile strength was enhanced up to 46.4% with the 1 wt% organoclay addition. Both tensile and flexural moduli increased up to 150.6% and 43% with the 3 wt% organoclay addition to the composites. However, the flexural strength of the composites was not improved with the organoclay addition. The addition of organoclay has also decreased the heat deflection temperature of the composites.

Strain-rate/temperature behavior of high density polyethylene in compression

NASA Technical Reports Server (NTRS)

Clements, L. L.; Sherby, O. D.

1978-01-01

The compressive strain rate/temperature behavior of highly linear, high density polyethylene was analyzed in terms of the predictive relations developed for metals and other crystalline materials. For strains of 5 percent and above, the relationship between applied strain rate, dotted epsilon, and resulting flow stress, sigma, was found to be: dotted epsilon exp times (Q sub f/RT) = k'(sigma/sigma sub c) to the nth power; the left-hand side is the activation-energy-compensated strain rate, where Q sub f is activation energy for flow, R is gas constant, and T is temperature; k is a constant, n is temperature-independent stress exponent, and sigma/sigma sub c is structure-compensated stress. A master curve resulted from a logarithmic plot of activation-energy-compensated strain rate versus structure-compensated stress.

Confocal Raman microscopy of morphological changes in poly(ethylene terephthalate) film induced by supercritical CO(2).

PubMed

Fleming, Oliver S; Kazarian, Sergei G

2004-04-01

Poly(ethylene terephthalate) (PET) film was exposed to supercritical (sc) CO(2) and confocal Raman microscopy was used to investigate the morphological changes induced. The study evaluates the use of oil and dry objectives in confocal mode to obtain depth profiles of PET film. These results were compared with the data obtained by mapping of the film cross-section. A significant gradient of degree of crystallinity normal to the surface of PET film down to 60 microm has been observed. The gradient of the degree of morphological changes are functions of exposure time and pressure.

An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends.

PubMed

Ahmed, Khalil

2015-11-01

Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (M L) and maximum torque (M H) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties.

An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends

PubMed Central

Ahmed, Khalil

2014-01-01

Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (ML) and maximum torque (MH) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties. PMID:26644917

Investigation of Thermal Properties of High-Density Polyethylene/Aluminum Nanocomposites by Photothermal Infrared Radiometry

NASA Astrophysics Data System (ADS)

Koca, H. D.; Evgin, T.; Horny, N.; Chirtoc, M.; Turgut, A.; Tavman, I. H.

2017-12-01

In this study, thermal properties of high-density polyethylene (HDPE) filled with nanosized Al particles (80 nm) were investigated. Samples were prepared using melt mixing method up to filler volume fraction of 29 %, followed by compression molding. By using modulated photothermal radiometry (PTR) technique, thermal diffusivity and thermal effusivity were obtained. The effective thermal conductivity of nanocomposites was calculated directly from PTR measurements and from the measurements of density, specific heat capacity (by differential scanning calorimetry) and thermal diffusivity (obtained from PTR signal amplitude and phase). It is concluded that the thermal conductivity of HDPE composites increases with increasing Al fraction and the highest effective thermal conductivity enhancement of 205 % is achieved at a filler volume fraction of 29 %. The obtained results were compared with the theoretical models and experimental data given in the literature. The results demonstrate that Agari and Uno, and Cheng and Vachon models can predict well the thermal conductivity of HDPE/Al nanocomposites in the whole range of Al fractions.

Biodegradation of HDPE by Aspergillus spp. from marine ecosystem of Gulf of Mannar, India.

PubMed

Sangeetha Devi, Rajendran; Rajesh Kannan, Velu; Nivas, Duraisamy; Kannan, Kanthaiah; Chandru, Sekar; Robert Antony, Arokiaswamy

2015-07-15

High density polyethylene (HDPE) is the most commonly found non-degradable solid waste among the polyethylene. In this present study, HDPE degrading various fungal strains were isolated from the polyethylene waste dumped marine coastal area and screened under in vitro condition. Based on weight loss and FT-IR Spectrophotometric analysis, two fungal strains designated as VRKPT1 and VRKPT2 were found to be efficient in HDPE degradation. Through the sequence analysis of ITS region homology, the isolated fungi were identified as Aspergillus tubingensis VRKPT1 and Aspergillus flavus VRKPT2. The biofilm formation observed under epifluorescent microscope had shown the viability of fungal strains even after one month of incubation. The biodegradation of HDPE film nature was further investigated through SEM analysis. HDPE poses severe environmental threats and hence the ability of fungal isolates was proved to utilize virgin polyethylene as the carbon source without any pre-treatment and pro-oxidant additives. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of HDPE plastic waste towards batako properties

NASA Astrophysics Data System (ADS)

Nursyamsi, N.; Indrawan, I.; Theresa, V.

2018-02-01

Indonesia is the world’s second largest producer of plastic waste to the sea, after China. Most of the plastic waste is polyethylene. Polyethylene is a polymer consisting of long chains of ethylene monomers. Moreover, polyethylene is plastic that has characteristics such as; thermoplastic, elastic, non-translucent, odorless, slightly opaque and transparent, resistant to impact and has a resistance of up to 135 degrees Celsius. The type of HDPE plastic (high-density polyethylene), which has been cleaned and chopped as a substitute of fine aggregate, is used in the brick’s making process. HDPE has a stronger, harder, smoother and more resistant to high-temperature properties. In this study, a weight variation of 0%, 10%, and 20% of HDPE plastic wastes was used from the total weight of sand as a substitution. Furthermore, the tensile and compressive strength were tested on day 7. Based on the research, the quality of the specimen achieved was categorized in quality III according to SNI 03-0349-1989.

Pyrolysis result of polyethylene waste as fuel for solid oxide fuel cell with samarium doped-ceria (SDC)-carbonate as electrolyte

NASA Astrophysics Data System (ADS)

Syahputra, R. J. E.; Rahmawati, F.; Prameswari, A. P.; Saktian, R.

2017-02-01

In this research, the result of pyrolysis on polyethylene was used as fuel for a solid oxide fuel cell (SOFC). The pyrolysis result is a liquid which consists of hydrocarbon chains. According to GC-MS analysis, the hydrocarbons mainly consist of C7 to C20 hydrocarbon chain. Then, the liquid was applied to a single cell of NSDC-L | NSDC | NSDC-L. NSDC is a composite SDC (samarium doped-ceria) with sodium carbonate. Meanwhile, NSDC-L is a composite of NSDC with LiNiCuO (LNC). NSDC and LNC were analyzed by X-ray diffraction to understand their crystal structure. The result shows that presence of carbonate did not change the crystal structure of SDC. SEM EDX analysis for fuel cell before and after being loaded with polyethylene oil to get information of element diffusion to the electrolyte. Meanwhile, the conductivity properties were investigated through impedance measurement. The presence of carbonate even increases the electrical conductivity. The single cell test with the pyrolysis result of polyethylene at 300 - 600 °C, found that the highest power density is at 600 °C with the maximum power density of 0.14 mW/cm2 and open circuit voltage of 0.4 Volt. Elemental analysis at three point spots of single cell NDSC-L |NSDC|NSDC-L found that a migration of ions was occurred during fuel operation at 300 - 600 °C.

Poly(ethylene oxide) Chains Are Not ``Hydrophilic'' When They Exist As Polymer Brush Chains

NASA Astrophysics Data System (ADS)

Lee, Hoyoung; Kim, Dae Hwan; Witte, Kevin N.; Ohn, Kimberly; Choi, Je; Kim, Kyungil; Meron, Mati; Lin, Binhua; Akgun, Bulent; Satija, Sushil; Won, You-Yeon

2012-02-01

By using a combined experimental and theoretical approach, a model poly(ethylene oxide) (PEO) brush system, prepared by spreading a poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) amphiphilic diblock copolymer onto an air-water interface, was investigated. The polymer segment density profiles of the PEO brush in the direction normal to the air-water interface under various grafting density conditions were determined from combined X-ray and neutron reflectivity data. In order to achieve a theoretically sound analysis of the reflectivity data, we developed a new data analysis method that uses the self-consistent field theoretical modeling as a tool for predicting expected reflectivity results for comparison with the experimental data. Using this new data analysis method, we discovered that the effective Flory-Huggins interaction parameter of the PEO brush chains is significantly greater than that corresponding to the theta condition, suggesting that contrary to what is more commonly observed for PEO in normal situations, the PEO chains are actually not ``hydrophilic'' when they exist as polymer brush chains, because of the many body interactions forced to be effective in the brush situation.

Helical instability in film blowing process: Analogy to buckling instability

NASA Astrophysics Data System (ADS)

Lee, Joo Sung; Kwon, Ilyoung; Jung, Hyun Wook; Hyun, Jae Chun

2017-12-01

The film blowing process is one of the most important polymer processing operations, widely used for producing bi-axially oriented film products in a single-step process. Among the instabilities observed in this film blowing process, i.e., draw resonance and helical motion occurring on the inflated film bubble, the helical instability is a unique phenomenon portraying the snake-like undulation motion of the bubble, having the period on the order of few seconds. This helical instability in the film blowing process is commonly found at the process conditions of a high blow-up ratio with too low a freezeline position and/or too high extrusion temperature. In this study, employing an analogy to the buckling instability for falling viscous threads, the compressive force caused by the pressure difference between inside and outside of the film bubble is introduced into the simulation model along with the scaling law derived from the force balance between viscous force and centripetal force of the film bubble. The simulation using this model reveals a close agreement with the experimental results of the film blowing process of polyethylene polymers such as low density polyethylene and linear low density polyethylene.

Preparation and Characterization of Antimicrobial Films Based on LDPE/Ag Nanoparticles with Potential Uses in Food and Health Industries.

PubMed

Olmos, Dania; Pontes-Quero, Gloria María; Corral, Angélica; González-Gaitano, Gustavo; González-Benito, Javier

2018-01-24

In this work, the antimicrobial effect of silver nanoparticles in polyethylene based nanocomposites has been investigated using a non-conventional processing method to produce homogeneous materials. High energy ball milling under cryogenic conditions was used to achieve a powder of well-blended low-density polyethylene and commercial silver nanoparticles. The final composites in the form of films were obtained by hot pressing. The effect of various silver nanoparticles content (0, 0.5, 1 and 2 wt %) on the properties of low-density polyethylene and the antimicrobial effectiveness of the composite against DH5α Escherichia coli were studied. The presence of silver nanoparticles did not seem to affect the surface energy and thermal properties of the materials. Apart from the inhibition of bacterial growth, slight changes in the aspect ratio of the bacteria with the content of particles were observed, suggesting a direct relationship between the presence of silver nanoparticles and the proliferation of DH5α E. coli ( Escherichia coli ) cells. Results indicate that these materials may be used to commercially produce antimicrobial polymers with potential applications in the food and health industries.

Preparation and Characterization of Antimicrobial Films Based on LDPE/Ag Nanoparticles with Potential Uses in Food and Health Industries

PubMed Central

Pontes-Quero, Gloria María; Corral, Angélica

2018-01-01

In this work, the antimicrobial effect of silver nanoparticles in polyethylene based nanocomposites has been investigated using a non-conventional processing method to produce homogeneous materials. High energy ball milling under cryogenic conditions was used to achieve a powder of well-blended low-density polyethylene and commercial silver nanoparticles. The final composites in the form of films were obtained by hot pressing. The effect of various silver nanoparticles content (0, 0.5, 1 and 2 wt %) on the properties of low-density polyethylene and the antimicrobial effectiveness of the composite against DH5α Escherichia coli were studied. The presence of silver nanoparticles did not seem to affect the surface energy and thermal properties of the materials. Apart from the inhibition of bacterial growth, slight changes in the aspect ratio of the bacteria with the content of particles were observed, suggesting a direct relationship between the presence of silver nanoparticles and the proliferation of DH5α E. coli (Escherichia coli) cells. Results indicate that these materials may be used to commercially produce antimicrobial polymers with potential applications in the food and health industries. PMID:29364193

Effect of thermal modification on rheological properties of polyethylene blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siriprumpoonthum, Monchai; Nobukawa, Shogo; Yamaguchi, Masayuki, E-mail: m-yama@jaist.ac.jp

2014-03-15

We examined the effects of thermal modification under flow field on the rheological properties of linear low-density polyethylene (LLDPE) with high molecular weight, low-density polyethylene (LDPE), and their blends, without thermal stabilizer. Although structural changes during processing are not detected by size extrusion chromatography or nuclear magnetic resonance spectroscopy, linear viscoelastic properties changed greatly, especially for the LLDPE. A cross-linking reaction took place, leading to, presumably, star-shaped long-chain branches. Consequently, the modified LLDPE, having high zero-shear viscosity, became a thermorheologically complex melt. Moreover, it should be noted that the drawdown force, defined as the uniaxial elongational force at a constantmore » draw ratio, was significantly enhanced for the blends. Enhancement of elongational viscosity was also detected. The drawdown force and elongational viscosity are marked for the thermally modified blend as compared with those for the blend of thermally modified pure components. Intermolecular cross-linking reactions between LDPE and LLDPE, yielding polymers with more than two branch points per chain, result in marked strain-hardening in the elongational viscosity behavior even at small strain. The recovery curve of the oscillatory modulus after the shear modification is further evidence of a branched structure.« less

Upcycling: converting waste plastics into paramagnetic, conducting, solid, pure carbon microspheres.

PubMed

Pol, Vilas Ganpat

2010-06-15

The recent tremendous increase in the volume of waste plastics (WP) will have a harmful environmental impact on the health of living beings. Hundreds of years are required to degrade WP in atmospheric conditions. Hence, in coming years, in addition to traditional recycling services, innovative "upcycling" processes are necessary. This article presents an environmentally benign, solvent-free autogenic process that converts various WP [low density polyethylene (LDPE), high density polyethylene (HDPE), polyethylene terephthalate (PET), polystyrene (PS), or their mixtures] into carbon microspheres (CMSs), an industrially significant, value-added product. The thermal dissociation of these individual or mixed WP in a closed reactor under autogenic pressure ( approximately 1000 psi) produced dry, pure powder of CMSs. In this paper, the optimization of process parameters such as the effect of mixing of WP with other materials, and the role of reaction temperature and time are reported. Employing advanced analytical techniques, the atomic structure, composition, and morphology of as-obtained CMSs were analyzed. The room-temperature paramagnetism in CMSs prepared from waste LDPE, HDPE, and PS was further studied by electron paramagnetic resonance (EPR). The conducting and paramagnetic nature of CMSs holds promise for their potential applications in toners, printers, paints, batteries, lubricants, and tires.

The effects of the concentration of high-density polyethylene particles on the bone-implant interface.

PubMed

Brooks, R A; Sharpe, J R; Wimhurst, J A; Myer, B J; Dawes, E N; Rushton, N

2000-05-01

We used a rat model in vivo to study the effects of the concentration of polyethylene particles on the bone-implant interface around stable implants in the proximal tibia. Intra-articular injections of 10(4), 10(6) or 10(8) high-density polyethylene (HDPE) particles per joint were given 8, 10 and 12 weeks after surgery. The animals were killed after 14 and 26 weeks and the response at the interface determined. Fibrous tissue was seen at the bone-implant interface when the head of the implant was flush with the top of the tibia but not when it was sunk below the tibial plateau. In the latter case the implant was completely surrounded by a shell of bone. The area of fibrous tissue and that of the gap between the implant and bone was related to the concentration of particles in the 14-week group (p < 0.05). Foreign-body granulomas containing HDPE particles were seen at the bone-implant interface in animals given 10(8) particles. The pathology resembles that seen around prostheses with aseptic loosening and we suggest that this is a useful model by which to study this process.

Durability of a fin-tube latent heat storage using high density polyethylene as PCM

NASA Astrophysics Data System (ADS)

Zauner, Christoph; Hengstberger, Florian; Etzel, Mark; Lager, Daniel; Hofmann, Rene; Walter, Heimo

2017-10-01

Polymers have rarely been used as storage materials in latent heat storages up to now. Thus, we systematically screened all polymers available on a large-scale, selected promising ones based on their theoretical properties and experimentally tested more than 50 candidates. We found that polyethylene, polyoxymethylene and polyamides are promising even as recycled material. Especially high density polyethylene (HDPE) turned out to be suitable as was shown by detailed thermophysical characterization including more than 1000 heating and cooling cycles for INEOS Rigidex HD6070EA. We built a storage with 170 kg HDPE and a total mass of 600 kg based on a fin-tube heat exchanger and characterized its energy capacity, power characteristics and temperature profiles using a thermal oil test rig. In total we performed 30 melting and crystallization cycles where the whole storage was above 100 °C for more than 140 hours. After usage we examined the interior of the storage by cutting it into various pieces. A thin layer of degradation was observed on the surfaces of the PCM which is most likely related to thermo-oxidative degeneration of HDPE. However, the bulk of the PCM is still intact as well as the heat exchanger itself.

Long-term field measurement of sorption of organic contaminants to five types of plastic pellets: implications for plastic marine debris.

PubMed

Rochman, Chelsea M; Hoh, Eunha; Hentschel, Brian T; Kaye, Shawn

2013-02-05

Concerns regarding marine plastic pollution and its affinity for chemical pollutants led us to quantify relationships between different types of mass-produced plastic and organic contaminants in an urban bay. At five locations in San Diego Bay, CA, we measured sorption of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) throughout a 12-month period to the five most common types of mass-produced plastic: polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), and polypropylene (PP). During this long-term field experiment, sorption rates and concentrations of PCBs and PAHs varied significantly among plastic types and among locations. Our data suggest that for PAHs and PCBs, PET and PVC reach equilibrium in the marine environment much faster than HDPE, LDPE, and PP. Most importantly, concentrations of PAHs and PCBs sorbed to HDPE, LDPE, and PP were consistently much greater than concentrations sorbed to PET and PVC. These data imply that products made from HDPE, LDPE, and PP pose a greater risk than products made from PET and PVC of concentrating these hazardous chemicals onto fragmented plastic debris ingested by marine animals.

Thermodynamics of single polyethylene and polybutylene glycols with hydrogen-bonding ends: A transition from looped to open conformations

NASA Astrophysics Data System (ADS)

Lee, Eunsang; Paul, Wolfgang

2018-02-01

A variety of linear polymer precursors with hydrogen bonding motifs at both ends enable us to design supramolecular polymer systems with tailored macroscopic properties including self-healing. In this study, we investigate thermodynamic properties of single polyethylene and polybutylene glycols with hydrogen bonding motifs. In this context, we first build a coarse-grained model of building blocks of the supramolecular polymer system based on all-atom molecular structures. The density of states of the single precursor is obtained using the stochastic approximation Monte Carlo method. Constructing canonical partition functions from the density of states, we find the transition from looped to open conformations at transition temperatures which are non-monotonously changing with an increasing degree of polymerization due to the competition between chain stiffness and loop-forming entropy penalty. In the complete range of chain length under investigation, a coexistence of the looped and open morphologies at the transition temperature is shown regardless of whether the transition is first-order-like or continuous. Polyethylene and polybutylene glycols show similar behavior in all the thermodynamic properties but the transition temperature of the more flexible polybutylene glycol is shown to change more gradually.

Surface chemistry changes and microstructure evaluation of low density nanocluster polyethylene under natural weathering: A spectroscopic investigation

NASA Astrophysics Data System (ADS)

Hamzah, M.; Khenfouch, M.; Rjeb, A.; Sayouri, S.; Houssaini, D. S.; Darhouri, M.; Srinivasu, VV

2018-03-01

Polyethylene is the most commonly used plastic in daily life, covering wide areas of application e.g. this polymer is used as a greenhouses covering material. This article investigates the effect of photo-oxidation on commercial unstabilised Low Density Polyethylene (uLDPE), as result of outdoor weathering factors. In this study, the samples were exposed for four months to the natural weather. The physico-chemical effects of natural ageing were studied by attenuated total reflection Fourier transform infrared (ATR-FTIR) and X-ray photoelectron (XPS) spectroscopy to elucidate the chemical composition, the nature of chemical bonds established and further to interrogate the changes that occur on the surface of the uLDPE samples. The main chemical change of uLDPE results in the formation of different kinds of carbonyl and vinyl groups identifiable in the ATR-FTIR and XPS spectra. The degree of crystallinity for these samples was calculated in terms of time exposure. An increase in the degree of crystallinity due to chemicrystallization was observed, which we indicative of the occurrences of chain scission. During outdoor exposure it was found that the photo-oxidation results in the formation of chain scission occurrences via Norrish type II reactions.

Foam vessel for cryogenic fluid storage

DOEpatents

Spear, Jonathan D [San Francisco, CA

2011-07-05

Cryogenic storage and separator vessels made of polyolefin foams are disclosed, as are methods of storing and separating cryogenic fluids and fluid mixtures using these vessels. In one embodiment, the polyolefin foams may be cross-linked, closed-cell polyethylene foams with a density of from about 2 pounds per cubic foot to a density of about 4 pounds per cubic foot.

Thermally induced conformational changes in polyethylene studied by two-dimensional near-infrared infrared hetero-spectral correlation spectroscopy

NASA Astrophysics Data System (ADS)

Watanabe, Shin; Noda, Isao; Ozaki, Yukihiro

2008-07-01

The amount of nonplanar gauche bonds was monitored as a function of increasing temperature in three different polyethylene (PE) samples by means of mid-infrared (MIR) and near-infrared (NIR) spectroscopy. The hetero-spectral two-dimensional (2D) correlation analysis was carried out between the NIR spectral region of 4365-4235 cm -1 and the well-established MIR spectral region of 1375-1265 cm -1, where bands due to nonplanar conformer are detected. This approach allowed us to identify the NIR band at 4265 cm -1, which behaves in a way similar to MIR bands originating from conformational-defect sequences. By combining the result of our current study and that of our previous report obtained on different types of PE, it is suggested that the NIR band originates from conformational-defect sequences in PE. This finding opens up a unique and useful way to study the state of conformational disorder in PE crystal by NIR spectroscopy, monitoring the intensity of the NIR band at 4265 cm -1. The use of NIR spectroscopy allows researchers to directly probe the degree in the formation of conformational-defect sequences in thick, real-world PE samples that cannot be studied by conventional MIR spectroscopy. The 2D correlation spectroscopy analysis among the MIR CH 2 wagging conformational-defect-mode bands on linear low-density PE (LLDPE) and low-density PE (LDPE) revealed the formation of nonplanar conformer represented by the band at 1368 cm -1 proceeds prior to those by other band at 1308 cm -1. This result agrees well with our previous finding on high-density PE (HDPE). We therefore propose with strong confidence that the bands at 1368 and 1308 cm -1 arise from different conformational-defect sequences, even though both of the bands have been proposed to arise from the same conformer of gtg' ( kink) + gtg sequence.

Laser-assisted photothermal imprinting of nanocomposite

NASA Astrophysics Data System (ADS)

Lu, Y.; Shao, D. B.; Chen, S. C.

2004-08-01

We report on a laser-assisted photothermal imprinting method for directly patterning carbon nanofiber-reinforced polyethylene nanocomposite. A single laser pulse from a solid state Nd :YAG laser (10ns pluse, 532 and 355nm wavelengths) is used to melt/soften a thin skin layer of the polymer nanocomposite. Meanwhile, a fused quartz mold with micro sized surface relief structures is pressed against the surface of the composite. Successful pattern transfer is realized upon releasing the quartz mold. Although polyethylene is transparent to the laser beam, the carbon nanofibers in the high density polyethylene (HDPE) matrix absorb the laser energy and convert it into heat. Numerical heat conduction simulation shows the HDPE matrix is partially melted or softened, allowing for easier imprinting of the relief pattern of the quartz mold.

The Influence of Sintering Method on Kaolin-Based Geopolymer Ceramics with Addition of Ultra High Molecular Weight Polyethylene as Binder

NASA Astrophysics Data System (ADS)

Romisuhani, A.; AlBakri, M. M.; Kamarudin, H.; Andrei, S. V.

2017-11-01

The influence of sintering method on kaolin-based geopolymer ceramics with addition of Ultra High Molecular Weight Polyethylene as binder were studied. Geopolymer were formed at room temperature from kaolin and sodium silicate in a highly alkaline medium, followed by curing and drying at 80 °C. 12 M of sodium hydroxide solution were mixed with sodium silicate at a ratio of 0.24 to form alkaline activator. Powder metallurgy technique were used in order to produce kaolin geopolymer ceramics with addition of Ultra High Molecular Weight Polyethylene. The samples were heated at temperature of 1200 °C with two different sintering method which are conventional method and two-step sintering method. The strength and density were tested.

Waste product profile: Polyethylene terephthalate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, C.

1996-02-01

Polyethylene terephthalate (PET) is a plastic resin used primarily to make bottles. Soft drinks are the primary product packaged in PET. Salad dressing, peanut butter, and other household and consumer products also use PET bottles. PET is also used for film, sheeting for cups and food trays, ovenable trays, and other uses. PET is a relatively new packaging resin, first commercialized in the early `70s. Because it is an ``engineered`` resin, it is more expensive than commodity resins such as high-density polyethylene (HDPE). The primary market for recycled PET is the fiber industry, which uses PET for carpet fiber, sweatersmore » and other clothing, and for other uses. Recycled PET can also be used for food and beverage containers. Export markets, particularly Asian countries, are becoming increasingly important.« less

A new theoretical formulation of coupling thermo-electric breakdown in LDPE film under dc high applied fields

NASA Astrophysics Data System (ADS)

Boughariou, F.; Chouikhi, S.; Kallel, A.; Belgaroui, E.

2015-12-01

In this paper, we present a new theoretical and numerical formulation for the electrical and thermal breakdown phenomena, induced by charge packet dynamics, in low-density polyethylene (LDPE) insulating film under dc high applied field. The theoretical physical formulation is composed by the equations of bipolar charge transport as well as by the thermo-electric coupled equation associated for the first time in modeling to the bipolar transport problem. This coupled equation is resolved by the finite-element numerical model. For the first time, all bipolar transport results are obtained under non-uniform temperature distributions in the sample bulk. The principal original results show the occurring of very sudden abrupt increase in local temperature associated to a very sharp increase in external and conduction current densities appearing during the steady state. The coupling between these electrical and thermal instabilities reflects physically the local coupling between electrical conduction and thermal joule effect. The results of non-uniform temperature distributions induced by non-uniform electrical conduction current are also presented for several times. According to our formulation, the strong injection current is the principal factor of the electrical and thermal breakdown of polymer insulating material. This result is shown in this work. Our formulation is also validated experimentally.

Biomaterials for Improved Wound Healing

DTIC Science & Technology

2013-10-01

is silver sulphadiazine (SSD) [6-7]. SSD possesses a broad spectrum of activity against gram- positive and gram-negative bacteria as well as fungi [8... polyethylene glycol-based fibrin gel (PEGylated fibrin gel) induces vasculogenesis both in vitro and in vivo [20]. To exploit the inherent ability of fibrin as...Loaded Chitosan Microspheres Impregnated in Polyethylene Glycol Fibrin Gels (SSD-CSM-PEGylated fibrin gels) and Adipose Derived Stem Cells embedded

Standing Up to Abuse.

ERIC Educational Resources Information Center

Wood, Heather

2002-01-01

Describes how barracks renovations at West Point have included the replacement of privacy partitions and screens in restrooms and locker rooms with items of high-density polyethylene (HDPE), which is more durable than metal. (EV)

Surface modification of polyethylene by radiation-induced grafting for adhesive bonding. V. Comparison with other surface treatments. [Gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamakawa, S.; Yamamoto, F.

1980-01-01

Helium gas plasma treatment of low-density polyethylene (LDPE) yields much lower peel strength than oxidative treatment using chromic acid and oxygen gas plasma. The practical adhesion, the bondability retention, and the bond durability of oxidatively treated LDPE sheets, bonded with epoxy adhesives, have been compared with those of partially hydrolyzed LDPE-methyl acrylate surface grafts. The oxidized surfaces easily lose the bondability by light rubbing with tissue paper, solvent extraction, heat aging, and artificial weathering, whereas the grafted surfaces retain the bondability. The bondability loss is due to removal of the oxidized layer, and the bondability retention is due to retentionmore » of the surface homopolymer layer. Conventional antioxidants stabilize the grafted but not the oxidized surfaces against thermal oxidative degradation. The grafted LDPE joints have much higher bond durability in humid environments than those of the oxidized LDPE joints. The dry and wet peel strengths of oxidized LDPE joints are greatly improved by application of primers consisting of a base epoxy resin and organic solvents. An adhesion mechanism involving penetration of epoxy adhesives into the oxidized layers and subsequent reinforcement of the layers by curing of the penetrated epoxy is proposed. 5 figures, 5 tables.« less

Peri-Implant Distribution of Polyethylene Debris in Postmortem-Retrieved Knee Arthroplasties: Can Polyethylene Debris Explain Loss of Cement-Bone Interlock in Successful Total Knee Arthroplasties?

PubMed

Cyndari, Karen I; Goodheart, Jacklyn R; Miller, Mark A; Oest, Megan E; Damron, Timothy A; Mann, Kenneth A

2017-07-01

Loss of mechanical interlock between cement and bone with in vivo service has been recently quantified for functioning, nonrevised, cemented total knee arthroplasties (TKAs). The cause of interlocking trabecular resorption is not known. The goal of this study is to quantify the distribution of PE debris at the cement-bone interface and determine if polyethylene (PE) debris is locally associated with loss of interlock. Fresh, nonrevised, postmortem-retrieved TKAs (n = 8) were obtained en bloc. Laboratory-prepared constructs (n = 2) served as negative controls. The intact cement-bone interface of each proximal tibia was embedded in Spurr's resin, sectioned, and imaged under polarized light to identify birefringent PE particles. PE wear particle number density was quantified at the cement-bone interface and distal to the interface, and then compared with local loss of cement-bone interlock. The average PE particle number density for postmortem-retrieved TKAs ranged from 8.6 (1.3) to 24.9 (3.1) particles/mm 2 (standard error) but was weakly correlated with years in service. The average particle number density was twice as high as distal (>5mm) to the interface compared to at the interface. The local loss of interlock at the interface was not related to the presence, absence, or particle density of PE. PE debris can migrate extensively along the cement-bone interface of well-fixed tibial components. However, the amount of local bone loss at the cement-bone interface was not correlated with the amount of PE debris at the interface, suggesting that the observed loss of trabecular interlock in these well-fixed TKAs may be due to alternative factors. Copyright © 2017 Elsevier Inc. All rights reserved.

Shear flow and carbon nanotubes synergistically induced nonisothermal crystallization of poly(lactic acid) and its application in injection molding.

PubMed

Tang, Hu; Chen, Jing-Bin; Wang, Yan; Xu, Jia-Zhuang; Hsiao, Benjamin S; Zhong, Gan-Ji; Li, Zhong-Ming

2012-11-12

The effect of shear flow and carbon nanotubes (CNTs), separately and together, on nonisothermal crystallization of poly(lactic acid) (PLA) at a relatively large cooling rate was investigated by time-resolved synchrotron wide-angle X-ray diffraction (WAXD) and polarized optical microscope (POM). Unlike flexible-chain polymers such as polyethylene, and so on, whose crystallization kinetics are significantly accelerated by shear flow, neat PLA only exhibits an increase in onset crystallization temperature after experiencing a shear rate of 30 s(-1), whereas both the nucleation density and ultimate crystallinity are not changed too much because PLA chains are intrinsically semirigid and have relatively short length. The breaking down of shear-induced nuclei into point-like precursors (or random coil) probably becomes increasingly active after shear stops. Very interestingly, a marked synergistic effect of shear flow and CNTs exists in enhancing crystallization of PLA, leading to a remarkable increase of nucleation density in PLA/CNT nanocomposite. This synergistic effect is ascribed to extra nuclei, which are formed by the anchoring effect of CNTs' surfaces on the shear-induced nuclei and suppressing effect of CNTs on the relaxation of the shear-induced nuclei. Further, this interesting finding was deliberately applied to injection molding, aiming to improve the crystallinity of PLA products. As expected, a remarkable high crystallinity in the injection-molded PLA part has been achieved successfully by the combination of shear flow and CNTs, which offers a new method to fabricate PLA products with high crystallinity for specific applications.

Cutting a Drop of Water Pinned by Wire Loops Using a Superhydrophobic Surface and Knife

PubMed Central

Yanashima, Ryan; García, Antonio A.; Aldridge, James; Weiss, Noah; Hayes, Mark A.; Andrews, James H.

2012-01-01

A water drop on a superhydrophobic surface that is pinned by wire loops can be reproducibly cut without formation of satellite droplets. Drops placed on low-density polyethylene surfaces and Teflon-coated glass slides were cut with superhydrophobic knives of low-density polyethylene and treated copper or zinc sheets, respectively. Distortion of drop shape by the superhydrophobic knife enables a clean break. The driving force for droplet formation arises from the lower surface free energy for two separate drops, and it is modeled as a 2-D system. An estimate of the free energy change serves to guide when droplets will form based on the variation of drop volume, loop spacing and knife depth. Combining the cutting process with an electrofocusing driving force could enable a reproducible biomolecular separation without troubling satellite drop formation. PMID:23029297

Wet self-cleaning of superhydrophobic microfiber adhesives formed from high density polyethylene.

PubMed

Lee, Jongho; Fearing, Ronald S

2012-10-30

Biologically inspired adhesives developed for switchable and controllable adhesion often require repetitive uses in general, dirty, environments. Superhydrophobic microstructures on the lotus leaf lead to exceptional self-cleaning of dirt particles on nonadhesive surfaces with water droplets. This paper describes the self-cleaning properties of a hard-polymer-based adhesive formed with high-aspect-ratio microfibers from high-density polyethylene (HDPE). The microfiber adhesive shows almost complete wet self-cleaning of dirt particles with water droplets, recovering 98% of the adhesion of the pristine microfiber adhesives. The low contact angle hysteresis indicates that the surface of microfiber adhesives is superhydrophobic. Theoretical and experimental studies reveal a design parameter, length, which can control the adhesion without affecting the superhydrophobicity. The results suggest some properties of biologically inspired adhesives can be controlled independently by adjusting design parameters.

Dodecylamine functionalization of carbon nanotubes to improve dispersion, thermal and mechanical properties of polyethylene based nanocomposites

NASA Astrophysics Data System (ADS)

Ferreira, F. V.; Franceschi, W.; Menezes, B. R. C.; Brito, F. S.; Lozano, K.; Coutinho, A. R.; Cividanes, L. S.; Thim, G. P.

2017-07-01

This study presents the effect of dodecylamine (DDA) functionalization of carbon nanotubes (CNTs) on the thermo-physical and mechanical properties of high-density polyethylene (HDPE) based composites. Here, we showed that the functionalization with DDA improved the dispersion of the CNTs as well as the interfacial adhesion with the HDPE matrix via non-covalent interactions. The better dispersion and interaction of CNT in the HDPE matrix as a function of the surface chemistry was correlated with the improved thermo-physical and mechanical properties.

Synthesis of linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite as an adsorbent for removal of Pb(ΙΙ) from aqueous solutions.

PubMed

Irani, Maryam; Ismail, Hanafi; Ahmad, Zulkifli; Fan, Maohong

2015-01-01

The purpose of this work is to remove Pb(II) from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy (FTIR), Solid carbon nuclear magnetic resonance spectroscopy (CNMR)), silicon(-29) nuclear magnetic resonance spectroscopy (Si NMR)), and X-ray diffraction spectroscope ((XRD) were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb(II) from the aqueous solution. The Pb(II)-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy (FTIR)), scanning electron microscopy (SEM)), and X-ray photoelectron spectroscopy ((XPS)). From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb(II). Kinetic studies indicated that the adsorption of Pb(II) followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb(II) ions was 430mg/g. Thus, the waste linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb(II) adsorbent. Copyright © 2014. Published by Elsevier B.V.

AFM study of the morphologic change of HDPE surface photografted with glycidyl methacrylate.

PubMed

Wang, Huiliang; Han, Jianmei

2009-05-01

The UV-induced grafting of glycidyl methacrylate (GMA) onto high-density polyethylene (HDPE) and the atomic force microscopy (AFM) study of the morphologic change of the grafted surface are reported. The grafting was carried out in GMA acetone solutions with different monomer concentrations. Grafting was much faster in a solution with a higher monomer concentration. FTIR analyses proved that GMA had been successfully grafted onto HDPE. The morphologies of grafted HDPE surfaces changed with UV irradiation time. The monomer concentration had a significant effect on the morphologies of the grafted HDPE surfaces. The HDPE surface grafted in a solution with a higher monomer concentration was much rougher than that grafted in a solution with a lower monomer concentration. The growth models of the grafted granules or clusters are also proposed.

Silver nanoparticles as a key feature of a plasma polymer composite layer in mitigation of charge injection into polyethylene under dc stress

NASA Astrophysics Data System (ADS)

Milliere, L.; Maskasheva, K.; Laurent, C.; Despax, B.; Boudou, L.; Teyssedre, G.

2016-01-01

The aim of this work is to limit charge injection from a semi-conducting electrode into low density polyethylene (LDPE) under dc field by tailoring the polymer surface using a silver nanoparticles-containing layer. The layer is composed of a plane of silver nanoparticles embedded in a semi-insulating organosilicon matrix deposited on the polyethylene surface by a plasma process. Size, density and surface coverage of the nanoparticles are controlled through the plasma process. Space charge distribution in 300 μm thick LDPE samples is measured by the pulsed-electroacoustic technique following a short term (step-wise voltage increase up to 50 kV mm-1, 20 min in duration each, followed by a polarity inversion) and a longer term (up to 12 h under 40 kV mm-1) protocols for voltage application. A comparative study of space charge distribution between a reference polyethylene sample and the tailored samples is presented. It is shown that the barrier effect depends on the size distribution and the surface area covered by the nanoparticles: 15 nm (average size) silver nanoparticles with a high surface density but still not percolating form an efficient barrier layer that suppress charge injection. It is worthy to note that charge injection is detected for samples tailored with (i) percolating nanoparticles embedded in organosilicon layer; (ii) with organosilicon layer only, without nanoparticles and (iii) with smaller size silver particles (<10 nm) embedded in organosilicon layer. The amount of injected charges in the tailored samples increases gradually in the samples ranking given above. The mechanism of charge injection mitigation is discussed on the basis of complementary experiments carried out on the nanocomposite layer such as surface potential measurements. The ability of silver clusters to stabilize electrical charges close to the electrode thereby counterbalancing the applied field appears to be a key factor in explaining the charge injection mitigation effect.

The Role of Interfaces in Polyethylene/Metal-Oxide Nanocomposites for Ultrahigh-Voltage Insulating Materials.

PubMed

Pourrahimi, Amir Masoud; Olsson, Richard T; Hedenqvist, Mikael S

2018-01-01

Recent progress in the development of polyethylene/metal-oxide nanocomposites for extruded high-voltage direct-current (HVDC) cables with ultrahigh electric insulation properties is presented. This is a promising technology with the potential of raising the upper voltage limit in today's underground/submarine cables, based on pristine polyethylene, to levels where the loss of energy during electric power transmission becomes low enough to ensure intercontinental electric power transmission. The development of HVDC insulating materials together with the impact of the interface between the particles and the polymer on the nanocomposites electric properties are shown. Important parameters from the atomic to the microlevel, such as interfacial chemistry, interfacial area, and degree of particle dispersion/aggregation, are discussed. This work is placed in perspective with important work by others, and suggested mechanisms for improved insulation using nanoparticles, such as increased charge trap density, adsorption of impurities/ions, and induced particle dipole moments are considered. The effects of the nanoparticles and of their interfacial structures on the mechanical properties and the implications of cavitation on the electric properties are also discussed. Although the main interest in improving the properties of insulating polymers has been on the use of nanoparticles, leading to nanodielectrics, it is pointed out here that larger microscopic hierarchical metal-oxide particles with high surface porosity also impart good insulation properties. The impact of the type of particle and its inherent properties (purity and conductivity) on the nanocomposite dielectric and insulating properties are also discussed based on data obtained by a newly developed technique to directly observe the charge distribution on a nanometer scale in the nanocomposite. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Olefin polymerization from single site catalysts confined within porous media

NASA Astrophysics Data System (ADS)

Kasi, Rajeswari M.

Single Site Catalysts (SSCs) have been utilized for olefin polymerization. Altering the metal-ligand architecture in the SSCs, polyolefin properties can be enhanced in a rational manner. This influence of the ligands in the SSC on the property of polyolefins prepared can be referred to as the primary ligand influence. Extending this understanding and subsequent control of the metal-ligand framework to the interaction of SSCs within organic and inorganic supports is vital for the synthesis of polyolefins with tailored properties. The motivation behind this thesis was to explore the support influence on the reactivity of the SSC tethered to a support matrix during ethylene homo and copolymerization. In order to address this question of the support influence on the final polyolefin properties, synthetic routes to covalently bind SSCs on different matrices have been explored. Two distinct supported SSCs have been used to prepare branched polyethylenes. Branched polyethylenes can be prepared by either copolymerization (ethylene and alpha-olefin) or oligomerization/copolymerization processes (ethylene and in situ generated alpha-olefin). Synthetic routes to prepare precursor catalysts to Constrained Geometry Catalysts (CGCs) by silyl elimination chemistry have been developed (Chapter 2). Efficient synthetic protocols to assemble CGCs on aminomethylpolysytrene matrices (Chapter 3) and amine-functionalized mesoporous silica (Chapter 4) are also reported. These supported catalysts, with appropriate cocatalysts have been used to prepare ethylene homo and copolymers, the polymer thermal properties and microstructures were analyzed by various analytical techniques. Branched polyethylenes (LLDPE) can be prepared by copolymerization chemistry. It has been observed is that the influence of the support is seen in the production of lower crystalline forms of high density polyethylene (HDPE, 20--50% crystalline), while homogeneous polymerization of analogous soluble CGCs afford HDPE of higher percent crystallinity (greater than 60% crystalline). High-density polyethylene with crystallinity of 40--60% can be prepared by using cocatalysts tethered to AMPS or silica in conjunction with analogous soluble, homogeneous CGCs (Chapter 6). Preparative methods to assemble piano stool complexes on hydroxy polystyrenes have been designed. These supported catalysts in conjunction with cocatalysts act as both oligomerization and copolymerization catalysts and allow the preparation of branched polyethylenes from ethylene only feed (Chapter 7).

Molecular Dynamics Simulations of Poly(ethylene oxide) Grafted onto Silica Immersed in Melt of Homopolymers.

PubMed

Benková, Zuzana; Cordeiro, M Natália D S

2015-09-22

Tuning of surface properties plays an important role in applications ranging from material engineering to biomedicine/chemistry. The interactions of chains grafted to a solid support and exposed to a matrix of chemically identical chains represent an intriguing issue. In this work, the behavior of poly(ethylene oxide) (PEO) chains grafted irreversibly onto an amorphous silica and immersed in the matrix of free PEO chains of different polymerization degree is studied using molecular dynamics simulations. The density distributions of grafted and free PEO chains, the height of the grafted layer, overlap parameters, and orientation order parameters depend not only on the grafting density but also on the length of free chains which confirm the entropic nature of the interactions between the grafted and free chains. In order to achieve a complete expulsion of the free chains from the grafted layer, a grafting density as high as 3.5 nm(-2) is necessary. Free PEO chains of 9 monomers leave the grafted layer at lower grafting densities than the longer PEO chains of 18 monomers in contrast with the theoretical predictions. The height of the grafted layer evolves with the grafting density in the presence of free chains in qualitative agreement with the theoretical phase diagram.

Radiation-induced graft copolymerization of poly(ethylene glycol) monomethacrylate onto deoxycholate-chitosan nanoparticles as a drug carrier

NASA Astrophysics Data System (ADS)

Pasanphan, Wanvimol; Rattanawongwiboon, Thitirat; Rimdusit, Pakjira; Piroonpan, Thananchai

2014-01-01

Poly(ethylene glycol) monomethacrylate-grafted-deoxycholate chitosan nanoparticles (PEGMA-g-DCCSNPs) were successfully prepared by radiation-induced graft copolymerization. The hydrophilic poly(ethylene glycol) monomethacrylate was grafted onto deoxycholate-chitosan in an aqueous system. The radiation-absorbed dose is an important parameter on degree of grafting, shell thickness and particle size of PEGMA-g-DCCSNPs. Owing to their amphiphilic architecture, PEGMA-g-DCCSNPs self-assembled into spherical core-shell nanoparticles in aqueous media. The particle size of PEGMA-g-DCCSNPs measured by TEM varied in the range of 70-130 nm depending on the degree of grafting as well as the irradiation dose. Berberine (BBR) as a model drug was encapsulated into the PEGMA-g-DCCSNPs. Drug release study revealed that the BBR drug was slowly released from PEGMA-g-DCCSNPs at a mostly constant rate of 10-20% in PBS buffer (pH 7.4) at 37 °C over a period of 23 days.

Improvement of adhesion properties of low density polyethylene (LDPE) substrate using atmospheric plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanchez-Nacher, L.; Garcia-Sanoguera, D.; Fenollar, O.

2010-06-02

In this work we have used atmospheric plasma technology on polyethylene surface with different treatment conditions. These modify surface pre-treatments on polyethylene, thus having a positive effect on overall surface activity of polymer surface and, consequently, adhesion properties can be remarkably improved. We have evaluated the influence of the nozzle/substrate distance and atmospheric plasma speed on wettability changes and adhesion properties. Wettability changes have been studied by contact angle measurements and subsequent surface energy calculation. Mechanical characterization of adhesion joints has been carried out in two different ways: peel and shear tensile test. The overall results show a remarkable increasemore » in mechanical properties of adhesion joints for low nozzle/substrate distances and low speed. So plasma atmospheric technology is highly useful to increase adhesion properties of polypropylene.« less

Anti-bacterial treatment of polyethylene by cold plasma for medical purposes.

PubMed

Popelka, Anton; Novák, Igor; Lehocký, Marián; Chodák, Ivan; Sedliačik, Ján; Gajtanska, Milada; Sedliačiková, Mariana; Vesel, Alenka; Junkar, Ita; Kleinová, Angela; Spírková, Milena; Bílek, František

2012-01-13

Polyethylene (PE) is one of the most widely used polymers in many industrial applications. Biomedical uses seem to be attractive, with increasing interest. However, PE it prone to infections and its additional surface treatment is indispensable. An increase in resistance to infections can be achieved by treating PE surfaces with substances containing antibacterial groups such as triclosan (5-Chloro-2-(2,4-dichlorophenoxy)phenol) and chlorhexidine (1,1'-Hexamethylenebis[5-(4-chlorophenyl)biguanide]). This work has examined the impact of selected antibacterial substances immobilized on low-density polyethylene (LDPE) via polyacrylic acid (PAA) grafted on LDPE by low-temperature barrier discharge plasma. This LDPE surface treatment led to inhibition of Escherichia coli and Staphylococcus aureus adhesion; the first causes intestinal disease, peritonitis, mastitis, pneumonia, septicemia, the latter is the reason for wound and urinary tract infections.

Biodegradability of degradable plastic waste.

PubMed

Agamuthu, P; Faizura, Putri Nadzrul

2005-04-01

Plastic waste constitutes the third largest waste volume in Malaysian municipal solid waste (MSW), next to putrescible waste and paper. The plastic component in MSW from Kuala Lumpur averages 24% (by weight), whereas the national mean is about 15%. The 144 waste dumps in the country receive about 95% of the MSW, including plastic waste. The useful life of the landfills is fast diminishing as the plastic waste stays un-degraded for more than 50 years. In this study the compostability of polyethylene and pro-oxidant additive-based environmentally degradable plastics (EDP) was investigated. Linear low-density polyethylene (LLDPE) samples exposed hydrolytically or oxidatively at 60 degrees C showed that the abiotic degradation path was oxidative rather than hydrolytic. There was a weight loss of 8% and the plastic has been oxidized as shown by the additional carbonyl group exhibited in the Fourier transform infra red (FTIR) Spectrum. Oxidation rate seemed to be influenced by the amount of pro-oxidant additive, the chemical structure and morphology of the plastic samples, and the surface area. Composting studies during a 45-day experiment showed that the percentage elongation (reduction) was 20% for McD samples [high-density polyethylene, (HDPE) with 3% additive] and LL samples (LLDPE with 7% additive) and 18% reduction for totally degradable plastic (TDP) samples (HDPE with 3% additive). Lastly, microbial experiments using Pseudomonas aeroginosa on carbon-free media with degradable plastic samples as the sole carbon source, showed confirmatory results. A positive bacterial growth and a weight loss of 2.2% for degraded polyethylene samples were evident to show that the degradable plastic is biodegradable.

Plasma-induced graft-polymerization of polyethylene glycol acrylate on polypropylene substrates

NASA Astrophysics Data System (ADS)

Zanini, S.; Orlandi, M.; Colombo, C.; Grimoldi, E.; Riccardi, C.

2009-08-01

A detailed study of argon plasma-induced graft-polymerization of polyethylene glycol acrylate (PEGA) on polypropylene (PP) substrates (membranes and films) is presented. The process consists of four steps: (a) plasma pre-activation of the PP substrates; (b) immersion in a PEGA solution; (c) argon plasma-induced graft-polymerization; (d) washing and drying of the samples. Influence of the solution and plasma parameters on the process efficiency evaluated in terms of amount of grafted polymer, coverage uniformity and substrates wettability, are investigated. The plasma-induced graft-polymerization of PEGA is then followed by sample weighting, water droplet adsorption time and contact angle measurements, attenuated total reflection infrared spectroscopy (ATR-IR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analyses. The stability of the obtained thin films was evaluated in water and in phosphate buffer saline (PBS) at 37 °C. Results clearly indicates that plasma-induced graft-polymerization of PEGA is a practical methodology for anti-fouling surface modification of materials.

Correlation of quantitative histopathological morphology and quantitative radiological analysis during aseptic loosening of hip endoprostheses.

PubMed

Bertz, S; Kriegsmann, J; Eckardt, A; Delank, K-S; Drees, P; Hansen, T; Otto, M

2006-01-01

Aseptic hip prosthesis loosening is the most important long-term complication in total hip arthroplasty. Polyethylene (PE) wear is the dominant etiologic factor in aseptic loosening, which together with other factors induces mechanisms resulting in bone loss, and finally in implant loosening. The single-shot radiograph analysis (EBRA, abbreviation for the German term "Einzel-Bild-Röntgenanalyse") is a computerized method for early radiological prediction of aseptic loosening. In this study, EBRA parameters were correlated with histomorphological parameters of the periprosthetic membrane. Periprosthetic membranes obtained from 19 patients during revision surgery of loosened ABG I-type total hip pros-theses were analyzed histologically and morphometrically. The pre-existing EBRA parameters, the thickness of the PE debris lay-er and the dimension of inclination and anteversion, were compared with the density of macrophages and giant cells. Addi-tionally, the semiquantitatively determined density of lymphocytes, plasma cells, giant cells and the size of the necrotic areas were correlated with the EBRA results. All periprosthetic membranes were classified as debris-induced type membranes. We found a positive correlation between the number of giant cells and the thickness of the PE debris layer. There was no significant correlation between the number of macrophages or all semiquantitative parameters and EBRA parameters. The number of giant cells decreased with implant duration. The morphometrically measured number of foreign body giant cells more closely reflects the results of the EBRA. The semiquantitative estimation of giant cell density could not substitute for the morphometrical analysis. The density of macrophages, lymphocytes, plasma cells and the size of necrotic areas did not correlate with the EBRA parameters, indicating that there is no correlation with aseptic loosening.

Biocompatibility of modified ultra-high-molecular-weight polyethylene

NASA Astrophysics Data System (ADS)

Novotná, Z.; Lacmanová, V.; Rimpelová, S.; Juřik, P.; Polívková, M.; Å vorčik, V.

2016-09-01

Ultra-high-molecular-weight polyethylene (UHMWPE, PE) is a synthetic polymer used for biomedical applications because of its high impact resistance, ductility and stability in contact with physiological fluids. Therefore this material is being used in human orthopedic implants such as total joint replacements. Surface modification of this material relates to changes of its surface hydrophilicity, energy, microstructure, roughness, and morphology, all influencing its biological response. In our recent work, PE was treated by an Ar+ plasma discharge and then grafted with biologically active polyethylene glycol in order to enhance adhesion and proliferation of mouse fibroblast (L929). The surface properties of pristine PE and its grafted counterparts were studied by goniometry (surface wettability). Furthermore, Atomic Force Microscopy was used to determine the surface morphology and roughness. The biological response of the L929 cell lines seeded on untreated and plasma treated PE matrices was quantified in terms of the cell adhesion, density, and metabolic activity. Plasma treatment leads to the ablation of the polymer surface layers. Plasma treatment and subsequent poly(ethylene glycol) grafting lead to dramatic changes in the polymer surface morphology and roughness. Biological tests, performed in vitro, show increased adhesion and proliferation of cells on modified polymers. Grafting with poly(ethylene glycol) increases cell proliferation compared to plasma treatment.

Polyethylene organo-clay nanocomposites: the role of the interface chemistry on the extent of clay intercalation/exfoliation.

PubMed

Mainil, Michaël; Alexandre, Michaël; Monteverde, Fabien; Dubois, Philippe

2006-02-01

High density polyethylene (HDPE)/clay nanocomposites have been prepared using three different functionalized polyethylene compatibilizers: an ethylene/vinyl acetate copolymer, a polyethylene grafted with maleic anhydride functions and a (styrene-b-ethylene/butylene-b-styrene) block copolymer. The nanocomposites were prepared via two different routes: (1) the dispersion in HDPE of a masterbatch prepared from the compatibilizer and the clay or (2) the direct melt blending of the three components. For each compatibilizer, essentially intercalated nanocomposites were formed as determined by X-ray diffraction and transmission electron microscopy. With the ethylene/vinyl acetate copolymer, a significant delamination of the intercalated clay in thin stacks was observed. This dispersion of thin intercalated stacks within the polymer matrix allowed increasing significantly the stiffness and the flame resistance of the nanocomposite. A positive effect of shear rate and blending time has also been put into evidence, especially for the process based on the masterbatch preparation, improving both the formation of thin stacks of intercalated clay and the mechanical properties and the flame resistance of the formed nanocomposites.

A new approach to the immobilisation of poly(ethylene oxide) for the reduction of non-specific protein adsorption on conductive substrates

NASA Astrophysics Data System (ADS)

Cole, Martin A.; Thissen, Helmut; Losic, Dusan; Voelcker, Nicolas H.

2007-04-01

Biomedical and biotechnological devices often require surface modifications to improve their performance. In most cases, uniform coatings are desired which provide a specific property or lead to a specific biological response. In the present work, we have generated pinhole-free coatings providing amine functional groups achieved by electropolymerisation of tyramine on highly doped silicon substrates. Furthermore, amine groups were used for the subsequent grafting of poly(ethylene oxide) aldehyde via reductive amination. All surface modification steps were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results indicate that the stability and the density of amine functional groups introduced at the surface via electropolymerisation compare favourably with alternative coatings frequently used in biomedical and biotechnological devices such as plasma polymer films. Furthermore, protein adsorption on amine and poly(ethylene oxide) coatings was studied by XPS and a colorimetric assay to test enzymatic activity. The grafting of poly(ethylene oxide) under cloud point conditions on electropolymerised tyramine layers resulted in surfaces with extremely low protein fouling character.

Natural Attenuation of the Persistent Chemical Warfare Agent ...

EPA Pesticide Factsheets

Report This project studied the influence of temperature on the natural attenuation of VX from five types of porous/permeable materials: unsealed concrete, plywood, rubber escalator handrail, high density polyethylene (HDPE) plastic, and acoustic ceiling tile.

Membranes and Films from Polymers.

ERIC Educational Resources Information Center

Blumberg, Avrom A.

1986-01-01

Provides background information on polymeric films and membranes including production methods, special industrial and medical applications, laboratory preparation, and an experimental investigation of a porous cellulose acetate membrane. Presents a demonstration to distinguish between high- and low-density polyethylene. (JM)

Development of an accelerated creep testing procedure for geosynthetics.

DOT National Transportation Integrated Search

1997-09-01

The report presents a procedure for predicting creep strains of geosynthetics using creep tests at elevated temperatures. Creep testing equipment was constructed and tests were performed on two types of geosynthetics: High Density Polyethylene (HDPE)...

An innovative recycling process to obtain pure polyethylene and polypropylene from household waste.

PubMed

Serranti, Silvia; Luciani, Valentina; Bonifazi, Giuseppe; Hu, Bin; Rem, Peter C

2015-01-01

An innovative recycling process, based on magnetic density separation (MDS) and hyperspectral imaging (HSI), to obtain high quality polypropylene and polyethylene as secondary raw materials, is presented. More in details, MDS was applied to two different polyolefin mixtures coming from household waste. The quality of the two separated PP and PE streams, in terms of purity, was evaluated by a classification procedure based on HSI working in the near infrared range (1000-1700 nm). The classification model was built using known PE and PP samples as training set. The results obtained by HSI were compared with those obtained by classical density analysis carried in laboratory on the same polymers. The results obtained by MDS and the quality assessment of the plastic products by HSI showed that the combined action of these two technologies is a valid solution that can be implemented at industrial level. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electrically and Thermally Conductive Low Density Polyethylene-Based Nanocomposites Reinforced by MWCNT or Hybrid MWCNT/Graphene Nanoplatelets with Improved Thermo-Oxidative Stability.

PubMed

Paszkiewicz, Sandra; Szymczyk, Anna; Pawlikowska, Daria; Subocz, Jan; Zenker, Marek; Masztak, Roman

2018-04-22

In this paper, the electrical and thermal conductivity and morphological behavior of low density polyethylene (LDPE)/multi-walled carbon nanotubes (MWCNTs) + graphene nanoplatelets (GNPs) hybrid nanocomposites (HNCs) have been studied. The distribution of MWCNTs and the hybrid of MWCNTs/GNPs within the polymer matrix has been investigated with scanning electron microscopy (SEM). The results showed that the thermal and electrical conductivity of the LDPE-based nanocomposites increased along with the increasing content of carbon nanofillers. However, one could observe greater improvement in the thermal and electrical conductivity when only MWCNTs have been incorporated. Moreover, the improvement in tensile properties and thermal stability has been observed when carbon nanofillers have been mixed with LDPE. At the same time, the increasing content of MWCNTs and MWCNTs/GNPs caused an increase in the melt viscosity with only little effect on phase transition temperatures.

New three-phase polymer-ceramic composite materials for miniaturized microwave antennas

NASA Astrophysics Data System (ADS)

Zhang, Li; Zhang, Jie; Yue, Zhenxing; Li, Longtu

2016-09-01

Unique polymer-ceramic composites for microwave antenna applications were prepared via melt extrusion using high-density polyethylene (HDPE) as the matrix and low-density polyethylene (LDPE) coated BaO-Nd2O3-TiO2 (BNT) ceramic-powders as the filler. By incorporating LDPE into the composites via a coating route, high ceramic-powder volume content (up to 50 vol%) could be achieved. The composites exhibited good microwave dielectric and thermomechanical behaviors. As BNT ceramic content increased from 10 vol% to 50 vol%, the permittivity of the composites increased from 3.45 (9 GHz) to 11.87 (7 GHz), while the dielectric loss remained lower than 0.0016. Microstrip antennas for applications in global positioning systems (GPS) were designed and fabricated from the composites containing 50 vol% BNT ceramics. The results indicate that the composites that have suitable permittivity and low dielectric loss are promising candidates for applications in miniaturized microwave devices, such as antennas.

A new strategy to produce low-density polyethylene (LDPE)-based composites simultaneously with high flame retardancy and high mechanical properties

NASA Astrophysics Data System (ADS)

Shen, Liguo; Li, Jianxi; Li, Renjie; Lin, Hongjun; Chen, Jianrong; Liao, Bao-Qiang

2018-04-01

In this study, a new strategy which blends low-density polyethylene (LDPE), magnesium hydroxide (MH) and lauryl acrylate by electron-beam radiation for production of LDPE-based composites with high performance was proposed. It was found that, MH played main roles in flame retardancy but reduced processing flow and mechanical properties of the composites. Meanwhile, melt flow rate (MFR) increased while viscosity of the composites decreased with lauryl acrylate content increased, facilitating LDPE composites processing. Electron beam radiation could prompt crosslinking of lauryl acrylate, which significantly enhanced the mechanical properties of LDPE composites. Meanwhile, lauryl acrylate addition only slightly decreased the flame retardancy, suggesting that LDPE composites could remain high flame retardancy even when lauryl acrylate content was high. The study highly demonstrated the feasibility to produce LDPE-based composites simultaneously with high flame retardancy and high mechanical properties by the blending strategy provided in this study.

Extraction of Volatile Flavor Compounds From Tobacco Leaf Through a Low-Density Polyethylene Membrane.

PubMed

Yokoi, Michinori; Shimoda, Mitsuya

2017-03-01

A low-density polyethylene (LDPE) membrane pouch method was developed to extract volatile flavor compounds from tobacco leaf. Tobacco leaf suspended in water was enclosed in a pouch prepared from a LDPE membrane of specific gravity 0.92 g/cm3 and 0.03 mm thickness and then extracted with diethyl ether. In comparison with direct solvent extraction, LDPE membrane excluded larger and higher boiling point compounds which could contaminate a gas chromatograph inlet and damage a column. Whilst being more convenient than a reduced-pressure steam distillation, it could extract volatile flavor compounds of wide range of molecular weight and polarity. Repeatabilities in the extracted amounts were ranged from 0.38% of 2.3-bipyridyl to 26% of β-ionone, and average value of 39 compounds was 5.9%. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Electrically and Thermally Conductive Low Density Polyethylene-Based Nanocomposites Reinforced by MWCNT or Hybrid MWCNT/Graphene Nanoplatelets with Improved Thermo-Oxidative Stability

PubMed Central

Pawlikowska, Daria; Subocz, Jan; Zenker, Marek; Masztak, Roman

2018-01-01

In this paper, the electrical and thermal conductivity and morphological behavior of low density polyethylene (LDPE)/multi-walled carbon nanotubes (MWCNTs) + graphene nanoplatelets (GNPs) hybrid nanocomposites (HNCs) have been studied. The distribution of MWCNTs and the hybrid of MWCNTs/GNPs within the polymer matrix has been investigated with scanning electron microscopy (SEM). The results showed that the thermal and electrical conductivity of the LDPE-based nanocomposites increased along with the increasing content of carbon nanofillers. However, one could observe greater improvement in the thermal and electrical conductivity when only MWCNTs have been incorporated. Moreover, the improvement in tensile properties and thermal stability has been observed when carbon nanofillers have been mixed with LDPE. At the same time, the increasing content of MWCNTs and MWCNTs/GNPs caused an increase in the melt viscosity with only little effect on phase transition temperatures. PMID:29690551

Application of glass particles doped by Zn(+2) as an antimicrobial and atoxic compound in LLDPE and HDPE.

PubMed

Santos, M F; Machado, C; Tachinski, C G; Júnior, J F; Piletti, R; Peterson, M; Fiori, M A

2014-06-01

This study demonstrates the potential application of glass particles doped with Zn(+2) (GZn) as an atoxic, antimicrobial additive when used in conjunction with high density polyethylene (HDPE) and linear low density polyethylene (LLDPE) polymers. Toxicity tests demonstrated that these modified glass particles were nontoxic to human cells, and atomic absorption analyses demonstrated the migration of ionic species in quantities less than 2.0ppm for both the HDPE/GZn and LLDPE/GZn compounds. Microbiological tests demonstrated the antimicrobial effect of the pure GZn compound as well as the polymeric HDPE/GZn and LLDPE/GZn compounds. In addition, at percentages of GZn higher than 2.00wt.% and at a time of 4h, the bactericidal performance is excellent and equal for both polymeric compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

Slip and frictional heating of extruded polyethylene melts

NASA Astrophysics Data System (ADS)

Pérez-González, José; Marín-Santibáñez, Benjamín M.; Zamora-López, Héctor S.; Rodríguez-González, Francisco

2017-05-01

Extrusion of polymer melts with slip at the die generates frictional heating. The relationship between slip flow and frictional heating during the continuous extrusion of a non-slipping linear low-density (LLDPE) and a slipping high-density polyethylene (HDPE), respectively, both pure as well as blended with a fluoropolymer processing aid (PA), was investigated in this work by Rheo-particle image velocimetry and thermal imaging. Significant rises in temperature were measured under slip and no slip conditions, being these much higher than the values predicted by the adiabatic flow assumption. Clear difference was made between viscous and frictional heating before the stick-slip regime for the LLDPE, even though they could not be distinguished from one another at higher stresses. Such a difference, however, could not be made for the slipping HDPE, since overall in the presence of slip, frictional and viscous heating act synergistically to increase the melt temperature.

The alterations in high density polyethylene properties with gamma irradiation

NASA Astrophysics Data System (ADS)

Zaki, M. F.; Elshaer, Y. H.; Taha, Doaa. H.

2017-10-01

In the present investigation, high density polyethylene (HDPE) polymer has been used to study the alterations in its properties under gamma-irradiation. Physico-chemical properties have been investigated with different spectroscopy techniques, Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), biocompatibility properties, as well as, mechanical properties change. The FT-IR analysis shows the formation of new band at 1716 cm-1 that is attributed to the oxidation of irradiated polymer chains, which is due to the formation of carbonyl groups (C˭O). XRD patterns show that a decrease in the crystallite size and increase in the Full Width at Half Maximum (FWHM). This means that the crystallinity of irradiated samples is decreased with increase in gamma dose. The contact angle measurements show an increase in the surface free energy as the gamma irradiation increases. The measurements of mechanical properties of irradiated HDPE samples were discussed.

Improvement of nuclide leaching resistance of paraffin waste form with low density polyethylene.

PubMed

Kim, Chang Lak; Park, Joo Wan; Kim, Ju Youl; Chung, Chang Hyun

2002-01-01

Low-level liquid borate wastes have been immobilized with paraffin wax using a concentrate waste drying system (CWDS) in Korean nuclear power plants. The possibility for improving chemical durability of paraffin waste form was suggested in this study. A small amount of low density polyethylene (LDPE) was added to increase the leaching resistance of the existing paraffin waste form. The influence of LDPE on the leaching behavior of waste form was investigated by performing leaching test according to ANSI/ANS-16.1 procedure during 325 days. It was observed that the leaching of nuclides immobilized within paraffin waste form made a marked reduction although little content of LDPE was added to waste form. The acceptance criteria of paraffin waste form associated with leachability index (LI) and compressive strength after the leaching test were fully satisfied with the help of LDPE.

Polyethylene oxide hydration in grafted layers

NASA Astrophysics Data System (ADS)

Dormidontova, Elena; Wang, Zilu

Hydration of water soluble polymers is one of the key-factors defining their conformation and properties, similar to biopolymers. Polyethylene oxide (PEO) is one of the most important biomedical-applications polymers and is known for its reverse temperature solubility due to hydrogen bonding with water. As in many practical applications PEO chains are grafted to surfaces, e.g. of nanoparticles or planar surfaces, it is important to understand PEO hydration in such grafted layers. Using atomistic molecular dynamic simulations we investigate the details of molecular conformation and hydration of PEO end-grafted to gold surfaces. We analyze polymer and water density distribution as a function of distance from the surface for different grafting densities. Based on a detailed analysis of hydrogen bonding between polymer and water in grafted PEO layers, we will discuss the extent of PEO hydration and its implication for polymer conformation, mobility and layer properties. This research is supported by NSF (DMR-1410928).

Sensitivity of Dielectric Properties to Wear Process on Carbon Nanofiber/High-Density Polyethylene Composites.

PubMed

Liu, Tian; Wood, Weston; Zhong, Wei-Hong

2011-12-01

We examined the correlation of wear effects with dielectric properties of carbon nanofibers (CNFs; untreated and organosilane-treated)-reinforced high-density polyethylene (HDPE) composites. Wear testing for the nanocomposites over up to 120 h was carried out, and then, dielectric permittivity and dielectric loss factor of the polymer composites with the increased wear time were studied. Scanning electron microscope and optical microscope observations were made to analyze the microstructure features of the nanocomposites. The results reveal that there exist approximate linear relationships of permittivity with wear coefficient for the nanocomposites. Composites containing silanized CNFs with the sufficiently thick coating exhibited high wear resistance. The change in permittivity was more sensitive to the increased wear coefficient for the nanocomposites with lower wear resistance. This work provides potential for further research on the application of dielectric signals to detect the effects of wear process on lifetime of polymeric materials.

Separation of n-hexane/acetone mixtures by pervaporation using high density polyethylene/ethylene propylene diene terpolymer rubber blend membranes.

PubMed

Kumar, P V Anil; Anilkumar, S; Varughese, K T; Thomas, Sabu

2012-01-15

Polymer membranes were prepared by blending high density polyethylene (HDPE) with ethylene propylene diene terpolymer rubber (EPDM). These blend membranes were evaluated for the selective separation of n-hexane from acetone. The flux and selectivity of the membranes were determined both as a function of the blend composition and feed mixture composition. Results showed that polymer blending method could be very useful to develop new membranes with improved selectivity. Pervaporation properties could be optimized by adjusting the blend composition. The effects of blend ratio, feed composition, and penetrant size on the pervaporation process were analyzed. The permeation properties have been explained on the basis of interaction between the membrane and solvents and blend morphology. Flux increases with increasing alkane content in the feed composition. Copyright © 2011 Elsevier B.V. All rights reserved.

Synthesis and characterization of novel low density polyethylene-multiwall carbon nanotube porous composites

NASA Astrophysics Data System (ADS)

Rizvi, Reza; Kim, Jae-Kyung; Naguib, Hani

2009-10-01

This study details the synthesis and characterization of novel porous composites of low density polyethylene (PE) and multiwalled carbon nanotubes (MWNT). PE-MWNT composites were prepared by melt blending the components in a twin screw compounder and porous structures were produced by a batch technique using CO2 as the solvent. The composites were characterized for dispersion using scanning electron microscopy and transmission electron microscopy; the results indicate a finely dispersed MWNT phase in PE. Thermal, rheological, electrical and mechanical properties of the composites were characterized and results indicate an electrical and rheological percolation threshold concentration of between 1 and 2 wt% MWNT in PE. Substantial improvements in the mechanical and electrical properties of PE were observed with the addition of 5 wt% MWNT. The porous PE-MWNT composites fabricated in this study were found to be conductive and have potential applications as anti-static materials for electrostatic discharge prevention.

The John Charnley Award: an accurate and sensitive method to separate, display, and characterize wear debris: part 1: polyethylene particles.

PubMed

Billi, Fabrizio; Benya, Paul; Kavanaugh, Aaron; Adams, John; Ebramzadeh, Edward; McKellop, Harry

2012-02-01

Numerous studies indicate highly crosslinked polyethylenes reduce the wear debris volume generated by hip arthroplasty acetabular liners. This, in turns, requires new methods to isolate and characterize them. We describe a method for extracting polyethylene wear particles from bovine serum typically used in wear tests and for characterizing their size, distribution, and morphology. Serum proteins were completely digested using an optimized enzymatic digestion method that prevented the loss of the smallest particles and minimized their clumping. Density-gradient ultracentrifugation was designed to remove contaminants and recover the particles without filtration, depositing them directly onto a silicon wafer. This provided uniform distribution of the particles and high contrast against the background, facilitating accurate, automated, morphometric image analysis. The accuracy and precision of the new protocol were assessed by recovering and characterizing particles from wear tests of three types of polyethylene acetabular cups (no crosslinking and 5 Mrads and 7.5 Mrads of gamma irradiation crosslinking). The new method demonstrated important differences in the particle size distributions and morphologic parameters among the three types of polyethylene that could not be detected using prior isolation methods. The new protocol overcomes a number of limitations, such as loss of nanometer-sized particles and artifactual clumping, among others. The analysis of polyethylene wear particles produced in joint simulator wear tests of prosthetic joints is a key tool to identify the wear mechanisms that produce the particles and predict and evaluate their effects on periprosthetic tissues.

Polystyrene plastic: a source and sink for polycyclic aromatic hydrocarbons in the marine environment

PubMed Central

Rochman, Chelsea M.; Manzano, Carlos; Hentschel, Brian T.; Massey Simonich, Staci L.; Hoh, Eunha

2014-01-01

Polycyclic aromatic hydrocarbons (PAHs) on virgin polystyrene (PS) and PS marine debris led us to examine PS as a source and sink for PAHs in the marine environment. At two locations in San Diego Bay, we measured sorption of PAHs to PS pellets, sampling at 0, 1, 3, 6, 9 and 12 months. We detected 25 PAHs using a new analytical method with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry. Several congeners were detected on samples before deployment. After deployment, some concentrations decreased (1,3-dimethylnaphthalene and 2,6-methylnaphthalene) while most increased (2-methylanthracene and all parent PAHs (PPAHs) except fluorene and fluoranthene), suggesting PS debris is a source and sink for PAHs. When comparing sorbed concentrations of PPAHs on PS to the five most common polymers (polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), and polypropylene (PP)), PS sorbed greater concentrations than PP, PET and PVC, similar to HDPE and LDPE. Most strikingly, at 0 months, PPAHs on PS ranged from 8-200 times greater than on PET, HDPE, PVC, LDPE, and PP. The combination of greater PAHs in virgin pellets and large sorption suggests that PS may pose a greater risk of exposure to PAHs upon ingestion. PMID:24341360

Polystyrene plastic: a source and sink for polycyclic aromatic hydrocarbons in the marine environment.

PubMed

Rochman, Chelsea M; Manzano, Carlos; Hentschel, Brian T; Simonich, Staci L Massey; Hoh, Eunha

2013-12-17

Polycyclic aromatic hydrocarbons (PAHs) on virgin polystyrene (PS) and PS marine debris led us to examine PS as a source and sink for PAHs in the marine environment. At two locations in San Diego Bay, we measured sorption of PAHs to PS pellets, sampling at 0, 1, 3, 6, 9, and 12 months. We detected 25 PAHs using a new analytical method with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry. Several congeners were detected on samples before deployment. After deployment, some concentrations decreased (1,3-dimethylnaphthalene and 2,6-methylnaphthalene), while most increased [2-methylanthracene and all parent PAHs (PPAHs), except fluorene and fluoranthene], suggesting that PS debris is a source and sink for PAHs. When sorbed concentrations of PPAHs on PS are compared to the five most common polymers [polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), and polypropylene (PP)], PS sorbed greater concentrations than PP, PET, and PVC, similar to HDPE and LDPE. Most strikingly, at 0 months, PPAHs on PS ranged from 8 to 200 times greater than on PET, HDPE, PVC, LDPE, and PP. The combination of greater PAHs in virgin pellets and large sorption suggests that PS may pose a greater risk of exposure to PAHs upon ingestion.

Task 3 - Pyrolysis of Plastic Waste. Semiannual report, November 1, 1996--March 31, 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ness, Robert O.; Aulich, Ted R.

1997-12-31

Over the last 50 years, the U.S. Department of Energy (DOE) has produced a wide variety of radioactive wastes from activities associated with nuclear defense and nuclear power generation. These wastes include low-level radioactive solid wastes, mixed wastes, and transuranic (TRU) wastes. A portion of these wastes consists of high- organic-content materials, such as resins, plastics, and other polymers; synthetic and natural rubbers; cellulosic-based materials; and oils, organic solvents, and chlorinated organic solvents. Many of these wastes contain hazardous and/or pyrophoric materials in addition to radioactive species. Physical forms of the waste include ion-exchange resins used to remove radioactive elementsmore » from nuclear reactor cooling water, lab equipment and tools (e.g., measurement and containment vessels, hoses, wrappings, equipment coverings and components, and countertops), oil products (e.g., vacuum pump and lubrication oils), bags and other storage containers (for liquids, solids, and gases), solvents, gloves, lab coats and anti-contamination clothing, and other items. Major polymer and chemical groups found in high-organic-content radioactive wastes include polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), Teflon(TM), polystyrene (PS), nylon, latex, polyethylene terephthalate (PET), vinyl, high-density polyethylene (HDPE), polycarbonate, nitriles, Tygon(R), butyl, and Tyvec(R).« less

Upcycling : converting waste plastics into paramagnetic, conducting, solid, pure carbon microspheres.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pol, V.

2010-06-15

The recent tremendous increase in the volume of waste plastics (WP) will have a harmful environmental impact on the health of living beings. Hundreds of years are required to degrade WP in atmospheric conditions. Hence, in coming years, in addition to traditional recycling services, innovative 'upcycling' processes are necessary. This article presents an environmentally benign, solvent-free autogenic process that converts various WP [low density polyethylene (LDPE), high density polyethylene (HDPE), polyethylene terephthalate (PET), polystyrene (PS), or their mixtures] into carbon microspheres (CMSs), an industrially significant, value-added product. The thermal dissociation of these individual or mixed WP in a closed reactormore » under autogenic pressure (1000 psi) produced dry, pure powder of CMSs. In this paper, the optimization of process parameters such as the effect of mixing of WP with other materials, and the role of reaction temperature and time are reported. Employing advanced analytical techniques, the atomic structure, composition, and morphology of as-obtained CMSs were analyzed. The room-temperature paramagnetism in CMSs prepared from waste LDPE, HDPE, and PS was further studied by electron paramagnetic resonance (EPR). The conducting and paramagnetic nature of CMSs holds promise for their potential applications in toners, printers, paints, batteries, lubricants, and tires.« less

Stability Study of Sunscreens with Free and Encapsulated UV Filters Contained in Plastic Packaging

PubMed Central

Briasco, Benedetta; Capra, Priscilla; Mannucci, Barbara; Perugini, Paola

2017-01-01

Sunscreens play a fundamental role in skin cancer prevention and in protection against photo-aging. UV filters are often photo-unstable, especially in relation to their vehicles and, being lipophilic substances, they are able to interact with plastic packaging. Finally, UV filter stability can be significantly affected by the routine use of the product at high temperatures. This work aims to study the stability of sunscreen formulations in polyethylene packaging. Butyl methoxydibenzoylmethane and octocrylene, both in a free form and as encapsulated filters were chosen as UV filters. Stability evaluations were performed both in the packaging and on the formulations. Moreover, a further two non-destructive techniques, near-infrared (NIR) spectroscopy and a multiple light scattering technique, were also used to evaluate the stability of the formulation. Results demonstrated clearly that all of the pack underwent significant changes in its elastic/plastic behavior and in external color after solar irradiation. From the evaluation of the extractable profile of untreated and treated packaging material an absorption of 2-phenoxyethanol and octocrylene were shown. In conclusion, the results highlighted clearly that a reduction of the UV filter in the formulation packed in high-density polyethylene/low-density polyethylene (HDPE/LDPE) material can occur over time, reducing the protective effect of the product when applied to the skin. PMID:28561775

Stability Study of Sunscreens with Free and Encapsulated UV Filters Contained in Plastic Packaging.

PubMed

Briasco, Benedetta; Capra, Priscilla; Mannucci, Barbara; Perugini, Paola

2017-05-31

Sunscreens play a fundamental role in skin cancer prevention and in protection against photo-aging. UV filters are often photo-unstable, especially in relation to their vehicles and, being lipophilic substances, they are able to interact with plastic packaging. Finally, UV filter stability can be significantly affected by the routine use of the product at high temperatures. This work aims to study the stability of sunscreen formulations in polyethylene packaging. Butyl methoxydibenzoylmethane and octocrylene, both in a free form and as encapsulated filters were chosen as UV filters. Stability evaluations were performed both in the packaging and on the formulations. Moreover, a further two non-destructive techniques, near-infrared (NIR) spectroscopy and a multiple light scattering technique, were also used to evaluate the stability of the formulation. Results demonstrated clearly that all of the pack underwent significant changes in its elastic/plastic behavior and in external color after solar irradiation. From the evaluation of the extractable profile of untreated and treated packaging material an absorption of 2-phenoxyethanol and octocrylene were shown. In conclusion, the results highlighted clearly that a reduction of the UV filter in the formulation packed in high-density polyethylene/low-density polyethylene (HDPE/LDPE) material can occur over time, reducing the protective effect of the product when applied to the skin.

Surface chemistry and mechanical property changes of wood-flour/high-density-polyethylene composites after accelerated weathering

Treesearch

Nicole M. Stark; Laurent M. Matuana

2004-01-01

Although wood–plastic composites have become more accepted and used in recent years and are promoted as low-maintenance, high-durability building products, they do experience a color change and a loss in mechanical properties with accelerated weathering. In this study, we attempted to characterize the modulus-of-elasticity (MOE) loss of photostabilized high- density...

E-Beam Processing of Polymer Matrix Composites for Multifunctional Radiation Shielding

NASA Technical Reports Server (NTRS)

Hou, Tan-Hung; Wilson, John W.; Jensen, Brian J.; Thibeault, Sheila A.; Chang, Chie K.; Kiefer, Richard L.

2005-01-01

Aliphatic polymers were identified as optimum radiation shielding polymeric materials for building multifunctional structural elements for in-space habitats. Conceptual damage tolerant configurations of polyolefins have been proposed, but many manufacturing issues relied on methods and materials which have sub-optimal radiation shielding characteristics (for example, epoxy matrix and adhesives). In the present approach, we shall investigate e-beam processing technologies for inclusion of high-strength aliphatic polymer reinforcement structures into a highly cross-linked polyolefin matrix. This paper reports the baseline thermo-mechanical properties of low density polyethylene and highly crystallized polyethylene.

Materials and Technologies Used in Wastewater Treatment

NASA Astrophysics Data System (ADS)

Moga, I. C.; Ardelean, I.; Donțu, O. G.; Moisescu, C.; Băran, N.; Petrescu, G.; Voicea, I.

2018-06-01

The biological wastewater treatment is based on biofilms activity. The biofilms can be fixed on biofilm carriers, that are made from varied materials, but most of them are made from high density polyethylene. The authors propose other mixtures of varied materials to obtain an increased load of microorganisms on biofilm carriers. During the experiments the load of microorganisms was increased up to 250% compared to the load on polyethylene biofilm carriers. Also, for the aerated biological tanks an innovative aeration system made from stainless steel pipes with fine pores (<1 mm) realized by electro-erosion, is proposed.

In Situ Manufacturing of Plastics and Composites to Support H&R Exploration

NASA Astrophysics Data System (ADS)

Carranza, Susana; Makel, Darby B.; Blizman, Brandon

2006-01-01

With the new direction of NASA to emphasize the exploration of the Moon, Mars and beyond, quick development and demonstration of efficient systems for In Situ Resources Utilization (ISRU) is more critical and timely than ever before. Beyond the production of life support consumables or propellants, long term missions will require much greater levels of utilization of indigenous resources, including fabrication of habitats, radiation shielding, and replacement parts and tools. This paper reports the development of a reactor system for the synthesis of polyethylene from carbon dioxide and water. One technology commonly found in most NASA In Situ Resources Utilization scenarios is the use of the Sabatier reaction and water electrolysis to produce methane and oxygen. The system presented uses methane and oxygen to produce ethylene, and subsequently ethylene is polymerized to produce polyethylene. The process selected enables the synthesis of high-density polyethylene suitable for the fabrication of many products for space exploration, including sheets, films, channels, etc, which can be used to construct extraterrestrial habitats, tools, replacement parts, etc. Conventional fabrication processes, such as extrusion and injection molding, which are used in the fabrication of polyethylene parts, can be adapted for space operation, making polyethylene a versatile feedstock for future in-situ manufacturing plants. Studies show that polyethylene is a very good radiation shield material, making it very suitable for construction of habitats, as well as incorporation in space suits. For the fabrication of massive structures, polyethylene can be combined with indigenous soil to maximize the use of unprocessed resources, either enclosed in channels, bags, etc., or compounded in varying proportions. The focus of this paper is to present current progress in the development of manufacturing systems and processes for the production of plastics and composites utilizing indigenous resources such as planetary atmosphere and soil.

Evaluation of experimental railroad-highway grade crossings in Louisiana.

DOT National Transportation Integrated Search

1983-08-01

This interim report was prepared to provide a review of the performance of thirty railroad-highway grade crossings installed experimentally in Louisiana between 1970 and 1983. They were constructed of rubber, high-density polyethylene (HDPE) or pre-c...

Optimization of high filler loading on tensile properties of recycled HDPE/PET blends filled with rice husk

NASA Astrophysics Data System (ADS)

Chen, Ruey Shan; Ahmad, Sahrim; Ghani, Mohd Hafizuddin Ab; Salleh, Mohd Nazry

2014-09-01

Biocomposites of recycled high density polyethylene / recycled polyethylene terephthalate (rHDPE/rPET) blend incorporated with rice husk flour (RHF) were prepared using a corotating twin screw extruder. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to improve the fibre-matrix interface adhesion. The effect of high filler loadings (50-90 wt%) on morphology and tensile properties of compatibilized rHDPE/rPET blend was investigated. The results of our study shown that composite with 70 wt% exhibited the highest tensile strength and Young's modulus, which are 22 MPa and 1752 MPa, respectively. The elongation at break decreased with increasing percentage of RHF. SEM micrograph confirmed fillers dispersion, morphological interaction and enhanced interfacial bonding between recycled polymer blends and rice husk. It can be concluded that the optimum RHF content is 70 wt% with maximum tensile strength.

Role of lipid phase separations and membrane hydration in phospholipid vesicle fusion.

PubMed

Hoekstra, D

1982-06-08

The relationship between lipid phase separation and fusion of small unilamellar phosphatidylserine-containing vesicles was investigated. The kinetics of phase separation were monitored by following the increase of self-quenching of the fluorescent phospholipid analogue N-(7-nitro-2,1,3-benzoxadiazol-4-yl)phosphatidylethanolamine, which occurs when the local concentration of the probe increases upon Ca2+-induced phase separation in phosphatidylserine (PS) bilayers [Hoekstra, D. (1982) Biochemistry 21, 1055-1061]. Fusion was determined by using the resonance energy transfer fusion assay [Struck, D. K., Hoekstra, D., & Pagano, R. E. (1981) Biochemistry 20, 4093-4099], which monitors the mixing of fluorescent lipid donor and acceptor molecules, resulting in an increase in energy transfer efficiency. The results show that in the presence of Ca2+, fusion proceeds much more rapidly (t 1/2 less than 5 s) than the process of phase separation (T 1/2 congruent to 1 min). Mg2+ also induced fusion, albeit at higher concentrations than Ca2+. Mg2+-induced phase separation were not detected, however. Subthreshold concentrations of Ca2+ (0.5 mM) or Mg2+ (2 mM) induced extensive fusion of PS-containing vesicles in poly(ethylene glycol) containing media. This effect did not appear to be a poly(ethylene glycol)-facilitated enhancement of cation binding to the bilayer, and consequently Ca2+-induced phase separation was not observed. The results suggest that macroscopic phase separation may facilitate but does not induced the fusion process and is therefore, not directly involved in the actual fusion mechanism. The fusion experiments performed in the presence of poly(ethylene glycol) suggest that the degree of bilayer dehydration and the creation of "point defects" in the bilayer without rigorous structural rearrangements in the membrane are dominant factors in the initial fusion events.

Biodiesel fuel production from waste cooking oil using radiation-grafted fibrous catalysts

NASA Astrophysics Data System (ADS)

Ueki, Yuji; Saiki, Seiichi; Hoshina, Hiroyuki; Seko, Noriaki

2018-02-01

Waste cooking oil, which can be used as a raw material for biodiesel fuel (BDF), contains two kinds of oil components: triglycerides (TGs) and free fatty acids (FFAs). Therefore, both alkaline-type and acid-type catalysts are needed to produce BDF from waste cooking oil. In this study, an alkaline-type grafted fibrous catalyst bearing OH- ions was synthesized by radiation-induced emulsion grafting of 4-chloromethylstyrene onto a polyethylene-coated polypropylene (PE/PP) nonwoven fabric, amination with trimethylamine, and further treatment with NaOH. Furthermore, an acid-type catalyst bearing H+ ions was synthesized by radiation-induced emulsion grafting of ethyl p-styrenesulfonate onto a PE/PP nonwoven fabric, saponification with NaOH, and protonation with HNO3. The OH- and H+ densities of the grafted fibrous catalysts were controlled by the grafting yield. The maximum OH- and H+ densities of the catalysts were 3.6 mmol-OH-/g-catalyst and 3.4 mmol-H+/g-catalyst, respectively. The performances of the catalysts were evaluated in the batchwise transesterification of TGs and ethanol, and the batchwise esterification of FFAs and ethanol. In both cases, TGs and FFAs were gradually converted into BDF. The mixed oil and four actual waste cooking oils, which contained both TGs and FFAs, were completely converted into BDF by sequential catalytic reactions with the acid-type grafted fibrous catalyst and then the alkaline-type grafted fibrous catalyst.

Wear performance of neat and vitamin E blended highly cross-linked PE under severe conditions: The combined effect of accelerated ageing and third body particles during wear test.

PubMed

Affatato, Saverio; De Mattia, Jonathan Salvatore; Bracco, Pierangiola; Pavoni, Eleonora; Taddei, Paola

2016-12-01

The objective of this study is to evaluate the effects of third-body particles on the in vitro wear behaviour of three different sets of polyethylene acetabular cups after prolonged testing in a hip simulator and accelerated ageing. Vitamin E-blended, cross-linked polyethylene (XLPE_VE), cross-linked polyethylene (XLPE) and conventional polyethylene (STD_PE) acetabular cups were simulator tested for two million cycles under severe conditions (i.e. by adding third-body particles to the bovine calf serum lubricant). Micro-Fourier Transform Infrared and micro-Raman spectroscopic analyses, differential scanning calorimetry, and crosslink density measurements were used to characterize the samples at a molecular level. The STD_PE cups had twice mass loss than the XLPE_VE components and four times than the XLPE samples; statistically significant differences were found between the mass losses of the three sets of cups. The observed wear trend was justified on the basis of the differences in cross-link density among the samples (XLPE>XLPE_VE>STD_PE). FTIR crystallinity profiles, bulk DSC crystallinity and surface micro-Raman crystallinity seemed to have a similar behaviour upon testing: all of them (as well as the all-trans and ortho-trans contents) revealed the most significant changes in XLPE and XLPE_VE samples. The more severe third-body wear testing conditions determined more noticeable changes in all spectroscopic markers with respect to previous tests. Unexpectedly, traces of bulk oxidation were found in both STD_PE (unirradiated) and XLPE (remelting-stabilized), which were expected to be stable to oxidation; on the contrary, XLPE_VE demonstrated a high oxidative stability in the present, highly demanding conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

A microdroplet cell culture based high frequency somatic embryogenesis system for pigeonpea, Cajanus cajan (L.) Millsp.

PubMed

Kumar, Nagan Udhaya; Gnanaraj, Muniraj; Sindhujaa, Vajravel; Viji, Maluventhen; Manoharan, Kumariah

2015-09-01

A protocol for high frequency production of somatic embryos was worked out in pigeonpea, Cajanus cajan (L.) Millsp. The protocol involved sequential employment of embryogenic callus cultures, low density cell suspension cultures and a novel microdroplet cell culture system. The microdroplet cell cultures involved culture of a single cell in 10 μI of Murashige and Skoog's medium supplemented with phytohormones, growth factors and phospholipid precursors. By employing the microdroplet cell cultures, single cells in isolation were grown into cell clones which developed somatic embryos. Further, 2,4-dichlorophenoxyacetic acid, kinetin, polyethylene glycol, putrescine, spermine, spermidine, choline chloride, ethanolamine and LiCl were supplemented to the low density cell suspension cultures and microdroplet cell cultures to screen for their cell division and somatic embryogenesis activity. Incubation of callus or the inoculum employed for low density cell suspension cultures and microdroplet cell cultures with polyethylene glycol was found critical for induction of somatic embryogenesis. Somatic embryogenesis at a frequency of 1.19, 3.16 and 6.51 per 10(6) cells was achieved in the callus, low density cell suspension cultures and microdroplet cell cultures, respectively. Advantages of employing microdroplet cell cultures for high frequency production of somatic embryos and its application in genetic transformation protocols are discussed.

Intermolecular interactions at early stage of protein/detergent particle association induced by salt/polyethylene glycol mixtures.

PubMed

Odahara, Takayuki; Odahara, Koji

2016-04-01

Mixtures of neutral salts and polyethylene glycol are used for various purposes in biological studies. Although the effects of each component of the mixtures are theoretically well investigated, comprehension of their integrated effects remains insufficient. In this work, their roles and effects as a precipitant were clarified by studying dependence of precipitation curves on salt concentration for integral membrane protein/detergent particles of different physicochemical properties. The dependence of precipitation curves was reasonably related to intermolecular interactions among relevant molecules such as protein, detergent and polyethylene glycol by considering their physicochemical properties. The obtained relationships are useful as basic information to learn the early stage of biological macromolecular associations. Copyright © 2015 Elsevier Inc. All rights reserved.

Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties.

PubMed

Elhag, Sami; Khun, Kimleang; Khranovskyy, Volodymyr; Liu, Xianjie; Willander, Magnus; Nur, Omer

2016-02-06

In this paper, we show that the possibility of using polyethylene glycol (EG) as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs). EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS) suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL) and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10(-6) M to 10(-3) M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties

PubMed Central

Elhag, Sami; Khun, Kimleang; Khranovskyy, Volodymyr; Liu, Xianjie; Willander, Magnus; Nur, Omer

2016-01-01

In this paper, we show that the possibility of using polyethylene glycol (EG) as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs). EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS) suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL) and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10−6 M to 10−3 M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices. PMID:26861342

Selecting Performance Reference Compounds (PRCS) for Low Density Polyethylene Passive Samplers

EPA Science Inventory

Use of equilibrium passive samplers for performing aquatic environmental monitoring at contaminated sites is becoming more common. However, a current challenge in passive sampling is determining when equilibrium is achieved between the sampler, target contaminants, and environm...

Physicochemical modifications accompanying UV laser induced surface structures on poly(ethylene terephthalate) and their effect on adhesion of mesenchymal cells.

PubMed

Rebollar, Esther; Pérez, Susana; Hernández, Margarita; Domingo, Concepción; Martín, Margarita; Ezquerra, Tiberio A; García-Ruiz, Josefa P; Castillejo, Marta

2014-09-07

This work reports on the formation of different types of structures on the surface of polymer films upon UV laser irradiation. Poly(ethylene terephthalate) was irradiated with nanosecond UV pulses at 193 and 266 nm. The polarization of the laser beam and the irradiation angle of incidence were varied, giving rise to laser induced surface structures with different shapes and periodicities. The irradiated surfaces were topographically characterized by atomic force microscopy and the chemical modifications induced by laser irradiation were inspected via micro-Raman and fluorescence spectroscopies. Contact angle measurements were performed with different liquids, and the results evaluated in terms of surface free energy components. Finally, in order to test the influence of surface properties for a potential application, the modified surfaces were used for mesenchymal stem cell culture assays and the effect of nanostructure and surface chemistry on cell adhesion was evaluated.

Curcumin Encapsulated into Methoxy Poly(Ethylene Glycol) Poly(ε-Caprolactone) Nanoparticles Increases Cellular Uptake and Neuroprotective Effect in Glioma Cells.

PubMed

Marslin, Gregory; Sarmento, Bruno Filipe Carmelino Cardoso; Franklin, Gregory; Martins, José Alberto Ribeiro; Silva, Carlos Jorge Ribeiro; Gomes, Andreia Ferreira Castro; Sárria, Marisa Passos; Coutinho, Olga Maria Fernandes Pereira; Dias, Alberto Carlos Pires

2017-03-01

Curcumin is a natural polyphenolic compound isolated from turmeric ( Curcuma longa ) with well-demonstrated neuroprotective and anticancer activities. Although curcumin is safe even at high doses in humans, it exhibits poor bioavailability, mainly due to poor absorption, fast metabolism, and rapid systemic elimination. To overcome these issues, several approaches, such as nanoparticle-mediated targeted delivery, have been undertaken with different degrees of success. The present study was conducted to compare the neuroprotective effect of curcumin encapsulated in poly( ε -caprolactone) and methoxy poly(ethylene glycol) poly( ε -caprolactone) nanoparticles in U251 glioblastoma cells. Prepared nanoparticles were physically characterized by laser doppler anemometry, transmission electron microscopy, and X-ray diffraction. The results from laser doppler anemometry confirmed that the size of poly( ε -caprolactone) and poly(ethylene glycol) poly( ε -caprolactone) nanoparticles ranged between 200-240 nm for poly( ε -caprolactone) nanoparticles and 30-70 nm for poly(ethylene glycol) poly( ε -caprolactone) nanoparticles, and transmission electron microscopy images revealed their spherical shape. Treatment of U251 glioma cells and zebrafish embryos with poly( ε -caprolactone) and poly(ethylene glycol) poly( ε -caprolactone) nanoparticles loaded with curcumin revealed efficient cellular uptake. The cellular uptake of poly(ethylene glycol) poly( ε -caprolactone) nanoparticles was higher in comparison to poly( ε -caprolactone) nanoparticles. Moreover, poly(ethylene glycol) poly( ε -caprolactone) di-block copolymer-loaded curcumin nanoparticles were able to protect the glioma cells against tBHP induced-oxidative damage better than free curcumin. Together, our results show that curcumin-loaded poly(ethylene glycol) poly( ε -caprolactone) di-block copolymer nanoparticles possess significantly stronger neuroprotective effect in U251 human glioma cells compared to free curcumin and curcumin-loaded poly( ε -caprolactone) nanoparticles. Georg Thieme Verlag KG Stuttgart · New York.

Hydrolytic degradation of poly(ethylene oxide)-block-polycaprolactone worm micelles.

PubMed

Geng, Yan; Discher, Dennis E

2005-09-21

Spherical micelles and nanoparticles made with degradable polymers have been of great interest for therapeutic application, but degradation-induced changes in a spherical morphology can be subtle and mechanism/kinetics appears poorly understood. Here, we report the first preparation of giant and flexible worm micelles self-assembled from degradable copolymer poly(ethylene oxide)-block-polycaprolactone. Such worm micelles spontaneously shorten to generate spherical micelles, triggered by polycaprolactone hydrolysis, with distinct mechanism and kinetics from that which occurs in bulk material.

Simultaneously and separately immobilizing incompatible dual-enzymes on polymer substrate via visible light induced graft polymerization

NASA Astrophysics Data System (ADS)

Zhu, Xing; He, Bin; Zhao, Changwen; Ma, Yuhong; Yang, Wantai

2018-04-01

Developing facile and mild strategy to construct multi-enzymes immobilization system has attracted considerable attentions in recent years. Here a simple immobilization strategy called visible light induced graft polymerization that can simultaneously and separately encapsulate two kinds of enzymes on one polymer film was proposed. Two incompatible enzymes, trypsin and transglutaminase (TGase) were selected as model dual-enzymes system and simultaneously immobilized on two sides of low-density polyethylene (LDPE) film. After immobilization, it was found that more than 90% of the enzymes can be embedded into dual-enzymes loaded film without leakage. And the activities of both separately immobilized enzymes were higher than the activities of mixed co-immobilized enzymes or the sequential immobilized ones. This dual-enzymes loaded film (DEL film) showed excellent recyclability and can retain >87% activities of both enzymes after 4 cycles of utilization. As an example, this DEL film was used to conjugate a prodrug of cytarabine with a target peptide. The successful preparation of expected product demonstrated that the separately immobilized two enzymes can worked well together to catalyze a two-step reaction.

Influence of Pro-Oxidant on Photodegradation of a Low-Density Polyethylene-Nanosilica Composite

EPA Science Inventory

Use of polymer nanocomposites is burgeoning and they represent one of the fastest growing components of the manufactured nanomaterials market. Incorporation of nanoscale fillers in these plastics significantly improves their stiffness and other key mechanical properties. Although...

Establishing a design procedure for buried steel-reinforced high density polyethylene (SRHDPE) pipes.

DOT National Transportation Integrated Search

2013-11-01

Metal and plastic pipes have been used extensively as storm sewers and buried drainage structures in transportation projects. Metal pipes have : high strength and stiffness but are susceptible to corrosion from wastewaters containing acid, and from a...

Microbial biofilm detection on food contact surfaces by macro-scale fluorescence imaging

USDA-ARS?s Scientific Manuscript database

Hyperspectral fluorescence imaging methods were utilized to evaluate the potential of multispectral fluorescence methods for detection of pathogenic biofilm formations on four types of food contact surface materials: stainless steel, high density polyethylene (HDPE) commonly used for cutting boards,...

Establishing a design procedure for buried steel-reinforced high-density polyethylene pipes : a field study, [technical summary].

DOT National Transportation Integrated Search

2015-11-01

Several national standards and specification have been developed for design, installation, : and materials for precast concrete pipe, corrugated metal pipe, and HDPE pipes. However, : no national accepted installation standard or design method is ava...

Mechanical and chemical effects of ion-texturing biomedical polymers

NASA Technical Reports Server (NTRS)

Weigand, A. J.; Cenkus, M. A.

1979-01-01

To determine whether sputter etching may provide substantial polymer surface texturing with insignificant changes in chemical and mechanical properties, an 8 cm beam diameter, electron bombardment, argon ion source was used to sputter etch (ion-texture process) nine biomedical polymers. The materials included silicone rubber, 32% carbon impregnated polyolefin, polyoxymethylene, polytetrafluoroethylene, ultrahigh molecular weight (UHMW) polyethylene, UHMW polyethylene with carbon fibers (10%), and several polyurethanes (bioelectric, segmented, and cross linked). Ion textured microtensile specimens of each material except UHMW polyethylene and UHMW polyethylene with 10% carbon fibers were used to determine the effect of ion texturing on tensile properties. Scanning electron microscopy was used to determine surface morphology changes, and electron spectroscopy for chemical analysis was used to analyze the near surface chemical changes that result from ion texturing. Ion energies of 500 eV with beam current densities ranging from 0.08 to 0.19 mA/sq cm were used to ion texture the various materials. Standard microtensile specimens of seven polymers were exposed to a saline environment for 24 hours prior to and during the tensile testing. The surface chemical changes resulting from sputter etching are minimal in spite of the often significant changes in the surface morphology.

Radiation damage and recovery properties of common plastics PEN (Polyethylene Naphthalate) and PET (Polyethylene Terephthalate) using a 137Cs gamma ray source up to 1.4 Mrad and 14 Mrad

NASA Astrophysics Data System (ADS)

Wetzel, J.; Tiras, E.; Bilki, B.; Onel, Y.; Winn, D.

2016-08-01

Polyethylene naphthalate (PEN) and polyethylene teraphthalate (PET) are cheap and common polyester plastics used throughout the world in the manufacturing of bottled drinks, containers for foodstuffs, and fibers used in clothing. These plastics are also known organic scintillators with very good scintillation properties. As particle physics experiments increase in energy and particle flux density, so does radiation exposure to detector materials. It is therefore important that scintillators be tested for radiation tolerance at these generally unheard of doses. We tested samples of PEN and PET using laser stimulated emission on separate tiles exposed to 1 Mrad and 10 Mrad gamma rays with a 137Cs source. PEN exposed to 1.4 Mrad and 14 Mrad emit 71.4% and 46.7% of the light of an undamaged tile, respectively, and maximally recover to 85.9% and 79.5% after 5 and 9 days, respectively. PET exposed to 1.4 Mrad and 14 Mrad emit 35.0% and 12.2% light, respectively, and maximally recover to 93.5% and 80.0% after 22 and 60 days, respectively.

Characterization of ecofriendly polyethylene fiber from plastic bag waste

NASA Astrophysics Data System (ADS)

Soekoco, Asril S.; Noerati, Komalasari, Maya; Kurniawan, Hananto, Agus

2017-08-01

This paper presents the characterization of fiber morphology, fiber count and tenacity of polyethylene fiber which is made from plastic bag waste. Recycling plastic bag waste into textile fiber has not developed yet. Plastic bag waste was recycled into fiber by melt spinning using laboratory scale melt spinning equipment with single orifice nozzle and plunger system. The basic principle of melt spinning is by melting materials and then extruding it through small orifice of a spinning nozzle to form fibers. Diameter and cross section shape of Recycled polyethylene fiber were obtained by using scanning electron microscope (SEM) instrumentation. Linear density of the recycled fiber were analyzed by calculation using denier and dTex formulation and The mechanical strength of the fibers was measured in accordance with the ASTM D 3379-75 standard. The cross section of recycled fiber is circular taking the shape of orifice. Fiber count of 303.75 denier has 1.84 g/denier tenacity and fiber count of 32.52 has 3.44 g/denier tenacity. This conditions is affected by the growth of polymer chain alignment when take-up axial velocity become faster. Recycled polyethylene fiber has a great potential application in non-apparel textile.

Combating oil spill problem using plastic waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saleem, Junaid, E-mail: junaidupm@gmail.com; Ning, Chao; Barford, John

Highlights: • Up-cycling one type of pollution i.e. plastic waste and successfully using it to combat the other type of pollution i.e. oil spill. • Synthesized oil sorbent that has extremely high oil uptake of 90 g/g after prolonged dripping of 1 h. • Synthesized porous oil sorbent film which not only facilitates in oil sorption but also increases the affinity between sorbent and oil by means of adhesion. - Abstract: Thermoplastic polymers (such as polypropylene, polyethylene, polyethylene terephthalate (PET) and high density polyethylene (HDPE)) constitute 5–15% of municipal solid waste produced across the world. A huge quantity of plasticmore » waste is disposed of each year and is mostly either discarded in landfills or incinerated. On the other hand, the usage of synthetic polymers as oil sorbents, in particular, polyolefins, including polypropylene (PP), and polyethylene (PE) are the most commonly used oil sorbent materials mainly due to their low cost. However, they possess relatively low oil absorption capacities. In this work, we provide an innovative way to produce a value-added product such as oil-sorbent film with high practical oil uptake values in terms of g/g from waste HDPE bottles for rapid oil spill remedy.« less

Tuning the superstructure of ultrahigh-molecular-weight polyethylene/low-molecular-weight polyethylene blend for artificial joint application.

PubMed

Xu, Ling; Chen, Chen; Zhong, Gan-Ji; Lei, Jun; Xu, Jia-Zhuang; Hsiao, Benjamin S; Li, Zhong-Ming

2012-03-01

An easy approach was reported to achieve high mechanical properties of ultrahigh-molecular-weight polyethylene (UHMWPE)-based polyethylene (PE) blend for artificial joint application without the sacrifice of the original excellent wear and fatigue behavior of UHMWPE. The PE blend with desirable fluidity was obtained by melt mixing UHMWPE and low molecular weight polyethylene (LMWPE), and then was processed by a modified injection molding technology-oscillatory shear injection molding (OSIM). Morphological observation of the OSIM PE blend showed LMWPE contained well-defined interlocking shish-kebab self-reinforced superstructure. Addition of a small amount of long chain polyethylene (2 wt %) to LMWPE greatly induced formation of rich shish-kebabs. The ultimate tensile strength considerably increased from 27.6 MPa for conventional compression molded UHMWPE up to 78.4 MPa for OSIM PE blend along the flow direction and up to 33.5 MPa in its transverse direction. The impact strength of OSIM PE blend was increased by 46% and 7% for OSIM PE blend in the direction parallel and vertical to the shear flow, respectively. Wear and fatigue resistance were comparable to conventional compression molded UHMWPE. The superb performance of the OSIM PE blend was originated from formation of rich interlocking shish-kebab superstructure while maintaining unique properties of UHMWPE. The present results suggested the OSIM PE blend has high potential for artificial joint application. © 2012 American Chemical Society

New developments in the field of high voltage and extra-high voltage cables

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jocteur, R.

1990-04-01

In this paper, the author presents the developments in progress at the present time in France concerning the high voltage (HV) and extra-high voltage (EHV) cables with synthetic insulation and their accessories up to the 500 kV range. The authors have adopted a maximum operating field strength approaching 16 kV/mm (405 V/mil) for low density polyethylene (LDPE) insulated cables. The on-going studies should allow to bring the maximum operating field strength for crosslinked polyethylene (XLPE) insulation from 7 to 10 kV/mm (180 to 255 V/mil) and cables could be manufactured more economically with this material.

Characterization of Viscoelastic Properties of Polymeric Materials Through Nanoindentation

NASA Technical Reports Server (NTRS)

Odegard, G. M.; Bandorawalla, T.; Herring, H. M.; Gates, T. S.

2003-01-01

Nanoindentation is used to determine the dynamic viscoelastic properties of six polymer materials. It is shown that varying the harmonic frequency of the nanoindentation does not have any significant effect on the measured storage and loss moduli of the polymers. Agreement is found between these results and data from DMA testing of the same materials. Varying the harmonic amplitude of the nanoindentation does not have a significant effect on the measured properties of the high performance resins, however, the storage modulus of the polyethylene decreases as the harmonic amplitude increases. Measured storage and loss moduli are also shown to depend on the density of the polyethylene.

Exploring multi potential uses of marine bacteria; an integrated approach for PHB production, PAHs and polyethylene biodegradation.

PubMed

Mohanrasu, K; Premnath, N; Siva Prakash, G; Sudhakar, Muniyasamy; Boobalan, T; Arun, A

2018-05-19

There are copious of bacteria exist in marine environment and it is very important to screen the potential microbes that has the ability to produce biopolymer polyhydroxybutyrate (PHB) as well as polycyclic aromatic hydrocarbons (PAHs) degradation and conventional plastic high density polyethylene (HDPE) biodegradation. Numerous studies have been investigated individually on either one of characteristic feature like PHB production, PAHs and high density polyethylene (HDPE) degradation, but not all together. Hence, in this study, we tried to screen potential marine microbes that have the ability to perform all three features. We have isolated 203 phenotyphicaly different colonies from 19 different sites (marine soil sediments, marine water and oil spilled marine water) which cover the north east to down south seashore regions of Tamilnadu, India. Of the 203 microbial isolates, the best PHB producing (Micrococcus luteus), PAHs degradation (Klebsiella pneumonia) and HDPE degradation (Brevibacillus borstelensis) microorganisms were identified through 16S rRNA sequencing. Analytical studies confirmed PHB production by fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance ( 1 H & 13 C NMR); PAHs degradation by high performance liquid chromatography (HPLC), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM); HDPE degradation by CLSM, FT-IR and SEM which cover the spectroscopy studies on biological systems. Copyright © 2018. Published by Elsevier B.V.

Validation of a model for the cast-film process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chambon, F.; Ohlsson, S.; Silagy, D.

1996-12-31

We have developed a model of the cast-film process and compared theoretical predictions against experiments on a pilot line. Three polyethylenes with a markedly different level of melt elasticity were used in this evaluation; namely, a high pressure low density polyethylene, LDPE, and two linear low density polyethylenes, LLDPE-1 and LLDPE-2. The final film dimensions of the LDPE were found to be in good agreement with 1-D viscoelastic stationary predictions. Flow field visualization experiments indicate, however, a 2-D velocity field in the airgap between the extrusion die and the chill roll. Taking this observation into account, evolutions of the freemore » surface of the web along the airgap were recorded with LLDPE-2, our least elastic melt. An excellent agreement is found between these measurements and predictions of neck-in and edge bead with 2-D Newtonian stationary simulations. The time-dependent solution, which is based on a linear stability analysis, allows to identify a zone of draw resonance within the working space of the process, defined by the draw ratio, the Deborah number, and the web aspect ratio. It is predicted that increasing this latter parameter stabilizes the process until an optimum value is reached. Experiments with LLDPE-1 are shown to validate this unique theoretical result, thus allowing to increase the draw ratio by about 75%.« less

In-situ Production of High Density Polyethylene and Other Useful Materials on Mars

NASA Technical Reports Server (NTRS)

Flynn, Michael

2005-01-01

This paper describes a revolutionary materials structure and power storage concept based on the in-situ production of abiotic carbon 4 compounds. One of the largest single mass penalties required to support the human exploration of Mars is the surface habitat. This proposal will use physical chemical technologies to produce high density polyethylene (HDPE) inflatable structures and construction materials from Mars atmospheric CO2. The formation of polyethylene from Mars CO2 is based on the use of the Sabatier and modified Fischer Tropsch reactions. The proposed system will fully integrate with existing in-situ propellant production concepts. The technology will also be capable of supplementing human caloric requirements, providing solid and liquid fuels for energy storage, and providing significant reduction in mission risk. The NASA Mars Reference Mission Definition Team estimated that a conventional Mars surface habitat structure would weigh 10 tonnes. It is estimated that this technology could reduce this mass by 80%. This reduction in mass will significantly contribute to the reduction in total mission cost need to make a Mars mission a reality. In addition the potential reduction of risk provided by the ability to produce C4 and potentially higher carbon based materials in-situ on Mars is significant. Food, fuel, and shelter are only three of many requirements that would be impacted by this research.

Phase behavior of blends of linear and branched polyethylenes in the molten and solid states by small-angle neutron scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alamo, R.G.; Mandelkern, L.; Londono, J.D.

1994-01-17

The state of mixing in blends of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) in the liquid and solid state has been examined by small-angle neutron scattering (SANS) in conjunction with deuterium labeling. In the melt, SANS results indicate that HDPE/LDPE mixtures from a single-phase solution for all concentrations, including blends containing high volume fractions ([phi] > 0.5) of branched polymer, for which multiphase melts have previously been suggested. Proper accounting for isotope effects is essential to avoid artifacts, because the H/D interaction parameter is sufficiently large ([sub [chi]HD] [approximately] 4 [times] 10[sup [minus]4]) to cause phase separation in themore » amorphous state for molecular weights (MW) >150,000. In the solid state, after slow cooling from the melt ([approximately]0.75 C/min), the HDPE/LDPE system shows extensive segregation into separate domains [approximately]100--300 [angstrom] in size. Both the shape and magnitude of the absolute scattering cross section are consistent with the conclusion that the components are extensively segregated into separate lamellae. Two-peak melting curves obtained for such mixtures support the SANS interpretation, and the segregation of components in the solid state is therefore a consequence of crystallization mechanisms rather than incompatibility in the liquid state.« less

Adhesion, Growth, and Maturation of Vascular Smooth Muscle Cells on Low-Density Polyethylene Grafted with Bioactive Substances

PubMed Central

Parizek, Martin; Slepickova Kasalkova, Nikola; Bacakova, Lucie; Bacakova, Marketa; Lisa, Vera; Svorcik, Vaclav

2013-01-01

The attractiveness of synthetic polymers for cell colonization can be affected by physical, chemical, and biological modification of the polymer surface. In this study, low-density polyethylene (LDPE) was treated by an Ar+ plasma discharge and then grafted with biologically active substances, namely, glycine (Gly), polyethylene glycol (PEG), bovine serum albumin (BSA), colloidal carbon particles (C), or BSA+C. All modifications increased the oxygen content, the wettability, and the surface free energy of the materials compared to the pristine LDPE, but these changes were most pronounced in LDPE with Gly or PEG, where all the three values were higher than in the only plasma-treated samples. When seeded with vascular smooth muscle cells (VSMCs), the Gly- or PEG-grafted samples increased mainly the spreading and concentration of focal adhesion proteins talin and vinculin in these cells. LDPE grafted with BSA or BSA+C showed a similar oxygen content and similar wettability, as the samples only treated with plasma, but the nano- and submicron-scale irregularities on their surface were more pronounced and of a different shape. These samples promoted predominantly the growth, the formation of a confluent layer, and phenotypic maturation of VSMC, demonstrated by higher concentrations of contractile proteins alpha-actin and SM1 and SM2 myosins. Thus, the behavior of VSMC on LDPE can be regulated by the type of bioactive substances that are grafted. PMID:23586032

Adhesion, growth, and maturation of vascular smooth muscle cells on low-density polyethylene grafted with bioactive substances.

PubMed

Parizek, Martin; Slepickova Kasalkova, Nikola; Bacakova, Lucie; Svindrych, Zdenek; Slepicka, Petr; Bacakova, Marketa; Lisa, Vera; Svorcik, Vaclav

2013-01-01

The attractiveness of synthetic polymers for cell colonization can be affected by physical, chemical, and biological modification of the polymer surface. In this study, low-density polyethylene (LDPE) was treated by an Ar(+) plasma discharge and then grafted with biologically active substances, namely, glycine (Gly), polyethylene glycol (PEG), bovine serum albumin (BSA), colloidal carbon particles (C), or BSA+C. All modifications increased the oxygen content, the wettability, and the surface free energy of the materials compared to the pristine LDPE, but these changes were most pronounced in LDPE with Gly or PEG, where all the three values were higher than in the only plasma-treated samples. When seeded with vascular smooth muscle cells (VSMCs), the Gly- or PEG-grafted samples increased mainly the spreading and concentration of focal adhesion proteins talin and vinculin in these cells. LDPE grafted with BSA or BSA+C showed a similar oxygen content and similar wettability, as the samples only treated with plasma, but the nano- and submicron-scale irregularities on their surface were more pronounced and of a different shape. These samples promoted predominantly the growth, the formation of a confluent layer, and phenotypic maturation of VSMC, demonstrated by higher concentrations of contractile proteins alpha-actin and SM1 and SM2 myosins. Thus, the behavior of VSMC on LDPE can be regulated by the type of bioactive substances that are grafted.

Changes in pectin methyl esterase activity with different packaging materials and stages of fruit harvesting during cold storage of pear cv. Punjab beauty.

PubMed

Kaur, Kirandeep; Dhillon, W S; Mahajan, B V C

2014-10-01

Pear cv. Punjab Beauty has become quite popular in Punjab. Excessive softening during cold storage leading to low shelf life is the major factor limiting its wider adoption. Studies were, therefore, conducted to determine the firmness and pectin methyl esterase (PME) activity at 4 harvest dates (2nd, 3rd and 4th week of July, and 1st week of August). Various packaging materials i.e. corrugated fiber board boxes and crates with high and low density polyethylene liners, corrugated fiber board boxes, crates and wooden boxes were also evaluated for their role in extending the shelf life of fruits. The enzyme activity and fruit firmness was evaluated periodically after 30, 45, 60 and 75 days of storage at 0-1 °C and 90-95 % RH. The firmness of the fruits decreased with the increase in storage intervals but the enzyme activity increased with the storage period up to 60 days and declined thereafter. Ripening-related changes in all the harvests were characterized mainly by an increase in the solubilization of pectin with a concomitant decrease in the degree of firmness. There was a continuous increase in enzyme activity with the advancement in harvesting dates and then fell sharply in the advanced ripening stages. Highest pectin methyl esterase activity was in fruits packed in crates followed by wooden boxes and corrugated fiber board boxes while the lowest was recorded in fruits packed in corrugated fiber board boxes with high density polyethylene liners. Therefore, high density polyethylene lined CFB boxes proved to be most effective in preventing the loss in firmness.

Separating effective high density polyethylene segments from olefin block copolymers using high temperature liquid chromatography with a preloaded discrete adsorption promoting solvent barrier.

PubMed

Chatterjee, Tirtha; Rickard, Mark A; Pearce, Eric; Pangburn, Todd O; Li, Yongfu; Lyons, John W; Cong, Rongjuan; deGroot, A Willem; Meunier, David M

2016-09-23

Recent advances in catalyst technology have enabled the synthesis of olefin block copolymers (OBC). One type is a "hard-soft" OBC with a high density polyethylene (HDPE) block and a relatively low density polyethylene (VLDPE) block targeted as thermoplastic elastomers. Presently, one of the major challenges is to fractionate HDPE segments from the other components in an experimental OBC sample (block copolymers and VLDPE segments). Interactive high temperature liquid chromatography (HTLC) is ineffective for OBC separation as the HDPE segments and block copolymer chains experience nearly identical enthalpic interactions with the stationary phase and co-elute. In this work we have overcome this challenge by using liquid chromatography under the limiting conditions of desorption (LC LCD). A solvent plug (discrete barrier) is introduced in front of the sample which specifically promotes the adsorption of HDPE segments on the stationary phase (porous graphitic carbon). Under selected thermodynamic conditions, VLDPE segments and block copolymer chains crossed the barrier while HDPE segments followed the pore-included barrier solvent and thus enabled separation. The barrier solvent composition was optimized and the chemical composition of fractionated polymer chains was investigated as a function of barrier solvent strength using an online Fourier-transform infrared (FTIR) detector. Our study revealed that both the HDPE segments as well as asymmetric block copolymer chains (HDPE block length≫VLDPE block length) are retained in the separation and the barrier strength can be tailored to retain a particular composition. At the optimum barrier solvent composition, this method can be applied to separate effective HDPE segments from the other components, which has been demonstrated using an experimental OBC sample. Copyright © 2016 Elsevier B.V. All rights reserved.

Formulation and stability of an extemporaneous 0.02% chlorhexidine digluconate ophthalmic solution.

PubMed

Lin, Shu-Chiao; Huang, Chih-Fen; Shen, Li-Jiuan; Wang, Hsueh-Ju; Lin, Chia-Yu; Wu, Fe-Lin Lin

2015-12-01

Acanthamoeba keratitis is difficult to treat because Acanthamoeba cysts are resistant to the majority of antimicrobial agents. Despite the efficacy of 0.02% chlorhexidine in treating Acanthamoeba keratitis, a lack of data in the literature regarding the formulation's stability limits its clinical use. The objective of this study was to develop an optimal extemporaneous 0.02% chlorhexidine digluconate ophthalmic formulation for patients in need. With available active pharmaceutical ingredients, 0.02% chlorhexidine digluconate sample solutions were prepared by diluting with BSS Plus Solution or acetate buffer. Influences of the buffer, type of container, and temperature under daily-open condition were assessed based on the changes of pH values and chlorhexidine concentrations of the test samples weekly. To determine the beyond-use date, the optimal samples were stored at 2-8°C or room temperature, and analyzed at time 0 and at Week 1, Week 2, Week 3, Week 4, Week 5, Week 8, Week 12, and Week 24. Despite chlorhexidine exhibiting better stability in acetate buffer than in BSS solution, its shelf-life was < 14 days when stored in a light-resistant low-density polyethylene container. The acetate-buffered 0.02% chlorhexidine digluconate solution stored in light-resistant high-density polyethylene eyedroppers did not exhibit significant changes in pH or strength at any time interval. The acetate-buffered 0.02% chlorhexidine digluconate ophthalmic solution stored in light-resistant high-density polyethylene eyedroppers demonstrated excellent stability at 2-25°C for 6 months after being sealed and for 1 month after opening. This finding will enable us to prepare 0.02% chlorhexidine digluconate ophthalmic solutions based on a doctor's prescription. Copyright © 2014. Published by Elsevier B.V.

Wearable supercapacitors on polyethylene terephthalate fabrics with good wash fastness and high flexibility

NASA Astrophysics Data System (ADS)

Wang, Guixia; Babaahmadi, Vahid; He, Nanfei; Liu, Yixin; Pan, Qin; Montazer, Majid; Gao, Wei

2017-11-01

All solid-state micro-supercapacitors (MSC) have emerged as attractive energy-storage units for portable and wearable electronics. Here, we describe a textile-based solid-state MSC via laser scribing of graphene oxide (GO) coatings on a flexible polyethylene terephthalate (PET) fabric. The laser-scribed graphene oxide layers (LGO) possess three-dimensionally porous structure suitable for electrochemical-double-layer formation. To improve the wash fastness and the flexibility of the as-prepared MSCs, glutaraldehyde (GA) was employed to crosslink the GO layers and PVA-gel electrolyte onto the PET fabric. The resultant all solid-state MSCs exhibited excellent flexibility, high areal specific capacitance (756 μF·cm-2 at 20 mV·s-1), and good rate capability when subject to bending and laundering. Furthermore, the MSC device showed a high power density of about 1.4 W·cm-3 and an energy density of 5.3 × 10-5 Wh·cm-3, and retained 98.3% of its initial capacitance after 1000 cycles at a current density of 0.5 mA·cm-2. This work is the first demonstration of in-plane MSCs on PET fabric surfaces with enhanced durability and flexibility.

Catalytic co-pyrolysis of waste vegetable oil and high density polyethylene for hydrocarbon fuel production.

PubMed

Wang, Yunpu; Dai, Leilei; Fan, Liangliang; Cao, Leipeng; Zhou, Yue; Zhao, Yunfeng; Liu, Yuhuan; Ruan, Roger

2017-03-01

In this study, a ZrO 2 -based polycrystalline ceramic foam catalyst was prepared and used in catalytic co-pyrolysis of waste vegetable oil and high density polyethylene (HDPE) for hydrocarbon fuel production. The effects of pyrolysis temperature, catalyst dosage, and HDPE to waste vegetable oil ratio on the product distribution and hydrocarbon fuel composition were examined. Experimental results indicate that the maximum hydrocarbon fuel yield of 63.1wt. % was obtained at 430°C, and the oxygenates were rarely detected in the hydrocarbon fuel. The hydrocarbon fuel yield increased when the catalyst was used. At the catalyst dosage of 15wt.%, the proportion of alkanes in the hydrocarbon fuel reached 97.85wt.%, which greatly simplified the fuel composition and improved the fuel quality. With the augment of HDPE to waste vegetable oil ratio, the hydrocarbon fuel yield monotonously increased. At the HDPE to waste vegetable oil ratio of 1:1, the maximum proportion (97.85wt.%) of alkanes was obtained. Moreover, the properties of hydrocarbon fuel were superior to biodiesel and 0 # diesel due to higher calorific value, better low-temperature low fluidity, and lower density and viscosity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rate of loss of simazine, terbuthylazine, isoproturon, and methabenzthiazuron during soil solarization.

PubMed

Navarro, Simón; Bermejo, Salvador; Vela, Nuria; Hernández, Joaquín

2009-07-22

This paper reports the use of solar heating by polyethylene mulching for decontamination of a silty clay-loam soil polluted with herbicides. Soil solarization, a natural and hydrothermal method commonly used for disinfesting soils, was tested during the summer season on a Hipercalcic Calcisol located in Murcia (southeast Spain) for dissipation of s-triazine (simazine and terbuthylazine) and phenylurea (isoproturon and methabenzthiazuron) herbicides using low-density (LD) and high-density (HD) polyethylene (PE) film as a cover. A well-established influence of the film was observed on the dissipation of all herbicides from the soil, although the density (0.92-0.95 g/cm(3)) of the film used (LDPE and HDPE) was not significant in terms of the rate of loss. In all cases, a quick depletion during the first 2 weeks was observed, mainly for terbuthylazine. The first-order model satisfactorily explained the dissipation process, but the Hoerl and biexponential equations were more appropriate, mainly for simazine, isoproturon, and methabenzthiazuron. In all cases, herbicides disappeared at faster rates in solarized soils (DT(50) = 4-29 days) than in nonmulched soils (DT(50) = 11-35 days), especially for terbuthylazine and isoproturon.

Polyethylene Wear in Retrieved Reverse Total Shoulder Components

PubMed Central

Day, Judd S; MacDonald, Daniel W; Olsen, Madeline; Getz, Charles; Williams, Gerald R; Kurtz, Steven M

2011-01-01

Background Reverse total shoulder arthroplasty has been used to treat rotator cuff tear arthropathy, proximal humeral fractures and for failed conventional total shoulder prostheses. It has been suggested that polyethylene wear is potentially higher in reverse shoulder replacements than in conventional shoulder replacements. The modes and degree of polyethylene wear have not been completely elucidated. The purpose of this study was to evaluate polyethylene wear patterns in seven specimens retrieved at revision arthroplasty and identify factors that may be associated with increased wear. Methods Reverse total shoulder components were retrieved from 7 patients during revision arthroplasty for loosening and/or pain. Pre-operative glenoid tilt and placement, and scapular notching were evaluated using pre-operative radiographs. Polyethylene wear was evaluated using microCT and optical microscopy. Results Wear on the rim of the polyethylene humeral cup, was identified on all retrieved components. The extent of rim wear varied from a penetration depth of 0.1 to 4.7 mm. We could not demonstrate a correlation between scapular notching and rim wear. However, rim wear was more extensive when the inferior screw had made contact with the liner. Metal on metal wear between the humeral component and the inferior screw of one component was also observed. Wear of the intended bearing surface was minimal. Discussion Rim damage was the predominant cause of polyethylene wear in our retrieved specimens. Direct contact between the humeral component and inferior metaglene screws is concerning because this could lead to accelerated UHMWPE wear and also induce mechanical loosening of the glenoid component. PMID:21724419

40 CFR 52.375 - Certification of no sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Certification of no sources. 52.375... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Connecticut § 52.375 Certification of no... of High-density Polyethylene and Polypropylene Resins. (e) Synthetic organic chemical manufacturing...

Experimental use of high density polyethylene drainage pipe as a cross roadway drainage structure.

DOT National Transportation Integrated Search

2001-01-01

Adequate drainage is one of the most important requirements in the reconstruction of a highway. Often it represents an appreciable expense of construction. In some applications installation costs may be reduced by the use of lighter weight drainage p...

STRESS CRACKING BEHAVIOR OF HDPE GEOMEMBRANES AND ITS PREVENTION

EPA Science Inventory

Geomembranes made from high density polyethylene (HOPE) have a high percent crystallinity and are therefore of concern with regard to stress cracking. A review of the literature plus our field exhuming of various sites-of-opportunity gave rise to twenty-five (25) situations wh...

Evaluating the precision of passive sampling methods using PRCs in the water column

EPA Science Inventory

Low-Density polyethylene (LDPE) sheets are often used as passive samplers for aquatic environmental monitoring to measure the dissolved concentrations of hydrophobic organic contaminants (HOCs). HOCs that are freely dissolved in water (Cfree) will partition into the LDPE until a ...

Establishing a design procedure for buried steel-reinforced high density polyethylene (SRHDPE) pipes : [technical summary].

DOT National Transportation Integrated Search

2013-11-01

Metal and plastic pipes have been used extensively as storm sewers and buried drainage structures in transportation projects. Metal pipes have high strength and stiffness but are susceptible to corrosion from wastewaters containing acid, and from agg...

Real-time monitoring of barrel thickness and barrel/screw separation using ultrasound

NASA Astrophysics Data System (ADS)

Jen, Cheng-Kuei; Zun, Zhigang; Kobayashi, Makiko

2005-03-01

Ultrasonic sensors together with a fast data acquisition system have been used to monitor the barrel thickness and barrel/screw separation during low-density polyethylene as well as high-density polyethylene extrusion in 30 mm and 50 mm twin-screw extruders. The sensors include sol-gel sprayed high temperature (HT) piezoelectric thick ceramic film ultrasonic transducers (UTs), stand-alone HTUTs and air-cooled buffer rod type sensors consisting of a room temperature UT and a non-clad or clad buffer rod to which the room temperature UT is attached. The installation and use of these sensors are non-intrusive to the extruder and non-destructive to the polymers being processed. This study has demonstrated the capability of appropriately designed ultrasonic sensors in monitoring the barrel and screw integrity at the melting, mixing and pumping zones of the extruder via barrel or flange. The merits and limitations of these sensors are discussed. The measurement speed and analysis of the sensitivity for quantitative wear measurements are also presented.

Ingestion of microplastic debris by green sea turtles (Chelonia mydas) in the Great Barrier Reef: Validation of a sequential extraction protocol.

PubMed

Caron, Alexandra G M; Thomas, Colette R; Berry, Kathryn L E; Motti, Cherie A; Ariel, Ellen; Brodie, Jon E

2018-02-01

Ocean contamination by plastics is a global issue. Although ingestion of plastic debris by sea turtles has been widely documented, contamination by microplastics (<5mm) is poorly known and likely to be under-reported. We developed a microplastic extraction protocol for examining green turtle (Chelonia mydas) chyme, which is multifarious in nature, by modifying and combining pre-established methods used to separate microplastics from organic matter and sediments. This protocol consists of visual inspection, nitric acid digestion, emulsification of residual fat, density separation, and chemical identification by Fourier transform infrared spectroscopy. This protocol enables the extraction of polyethylene, high-density polyethylene, (aminoethyl) polystyrene, polypropylene, and polyvinyl chloride microplastics >100μm. Two macroplastics and seven microplastics (two plastic paint chips and five synthetic fabric particles) were isolated from subsamples of two green turtles. Our results highlight the need for more research towards understanding the impact of microplastics on these threatened marine reptiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhanced antioxidant activity of polyolefin films integrated with grape tannins.

PubMed

Olejar, Kenneth J; Ray, Sudip; Kilmartin, Paul A

2016-06-01

A natural antioxidant derived from an agro-waste of the wine industry, grape tannin, was incorporated by melt blending into three different polyolefins (high-density polyethylene, linear low-density polyethylene and polypropylene) to introduce antioxidant functionality. Significant antioxidant activity was observed at 1% tannin inclusion in all polymer blends. The antioxidant activity was observed to increase steadily with a greater concentration of grape tannins, the highest increases being seen with polypropylene. The mechanical and thermal properties of the polymer films following antioxidant incorporation were minimally altered with up to 3% grape tannins. All of the polyolefin-grape tannin films successfully passed the leachability test following USP661 standard protocol. Superior antioxidant activity was established in polyolefin thin films by utilization of a bulk grape extract obtained from winery waste. Significant increases in antioxidant activity were seen with 1% extract inclusion. This not only demonstrates the potential for food packaging applications of the polyolefin blends, but also valorizes the agro-waste. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Tensile properties and water absorption assessment of linear low-Density Polyethylene/Poly (Vinyl Alcohol)/Kenaf composites: effect of eco-friendly coupling agent

NASA Astrophysics Data System (ADS)

Pang, A. L.; Ismail, H.; Abu Bakar, A.

2018-02-01

Linear low-density polyethylene (LLDPE)/poly (vinyl alcohol) (PVOH) filled with untreated kenaf (UT-KNF) and eco-friendly coupling agent (ECA)-treated kenaf (ECAT-KNF) were prepared using ThermoHaake internal mixer, respectively. Filler loadings of UT-KNF and ECAT-KNF used in this study are 10 and 40 parts per hundred parts of resin (phr). The effect of ECA on tensile properties and water absorption of LLDPE/PVOH/KNF composites were investigated. Field emission scanning electron microscopy (FESEM) analysis was applied to visualize filler-matrix adhesion. The results indicate LLDPE/PVOH/ECAT-KNF composites possess higher tensile strength and tensile modulus, but lower elongation at break compared to LLDPE/PVOH/UT-KNF composites. The morphological studies of tensile fractured surfaces using FESEM support the increment in tensile properties of LLDPE/PVOH/ECAT-KNF composites. Nevertheless, LLDPE/PVOH/UT-KNF composites reveal higher water absorption compared to LLDPE/PVOH/ECAT-KNF composites.

Alternative polymer separation technology by centrifugal force in a melted state.

PubMed

Dobrovszky, Károly; Ronkay, Ferenc

2014-11-01

In order to upgrade polymer waste during recycling, separation should take place at high purity. The present research was aimed to develop a novel, alternative separation opportunity, where the polymer fractions were separated by centrifugal force in melted state. The efficiency of the constructed separation equipment was verified by two immiscible plastics (polyethylene terephthalate, PET; low density polyethylene, LDPE), which have a high difference of density, and of which large quantities can also be found in the municipal solid waste. The results show that the developed equipment is suitable not only for separating dry blended mixtures of PET/LDPE into pure components again, but also for separating prefabricated polymer blends. By this process it becomes possible to recover pure polymer substances from multi-component products during the recycling process. The adequacy of results was verified by differential scanning calorimetry (DSC) measurement as well as optical microscopy and Raman spectroscopy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development and quality evaluation of quick cooking dhal-A convenience product.

PubMed

Sethi, Shruti; Samuel, D V K; Khan, Islam

2014-03-01

Owing to rapid urbanization and more women joining the workforce, use of ready-to-eat and ready-to-use convenience foods is gaining increasing popularity. Women require dhal that cooks fast and increases in volume when cooked. In an attempt to prepare quick cooking dhal from pigeon pea, variety UPAS 120 was milled, pre-treated with sodium chloride solution (1%), flaked and dried. The quick cooking dhal was packed in three packaging materials, namely, high molecular weight high density polyethylene (HMHDPE), high density polyethylene (HDPE) and laminated pouches. The quality evaluation of the prepared flakes with respect to the cooking quality attributes, changes in proximate composition, free fatty acid (FFA) and peroxide value (PV) were carried out during storage at ambient temperature (8-36°C) at regular intervals for a period of 10 months. During storage, quick cooking dhal packed in laminated pouches performed better than samples stored in other pouches with respect to the changes in the overall quality and acceptability of the product.

Effect of Nanoparticles on the Morphology, Thermal, and Electrical Properties of Low-Density Polyethylene after Thermal Aging

PubMed Central

Wang, Youyuan; Zhang, Zhanxi; Xiao, Kun

2017-01-01

This paper investigates the morphology, thermal, and electrical properties of LDPE (low-density polyethylene)-based nanocomposites after thermal aging. The FTIR (Fourier transform infrared spectroscopy) spectra results show that thermo-oxidative reactions occur in neat LDPE and LDPE/SiO2 nanocomposites when the aging time is 35 days and in LDPE/MgO nanocomposites when the aging time is 77 days. Specifically, LDPE/MgO nanocomposites delay the appearance of thermo-oxidative reactions, showing anti-thermal aging ability. Furthermore, nanocomposites present lower onset degradation temperature than neat LDPE, showing better thermal stabilization. With regard to the electrical properties, nanocomposites maintain the ability to suppress space charge accumulation after thermal aging. Additionally, in comparison with SiO2 nanocomposites and neat LDPE, the permittivity of LDPE/MgO nanocomposites changes slightly after thermal aging. It is concluded that LDPE/MgO nanocomposites have better insulation properties than neat LDPE after thermal aging, which may be caused by the interface introduced by the nanoparticles. PMID:29023428

Fast microwave-assisted catalytic co-pyrolysis of lignin and low-density polyethylene with HZSM-5 and MgO for improved bio-oil yield and quality.

PubMed

Fan, Liangliang; Chen, Paul; Zhang, Yaning; Liu, Shiyu; Liu, Yuhuan; Wang, Yunpu; Dai, Leilei; Ruan, Roger

2017-02-01

Fast microwave-assisted catalytic co-pyrolysis of lignin and low-density polyethylene (LDPE) with HZSM-5 and MgO was investigated. Effects of pyrolysis temperature, lignin to LDPE ratio, MgO to HZSM-5 ratio, and feedstock to catalyst ratio on the products yields and chemical profiles were examined. 500°C was the optimal co-pyrolysis temperature in terms of the maximum bio-oil yield. The proportion of aromatics increased with increasing LDPE content. In addition, with the addition of LDPE (lignin/LDPE=1/2), methoxyl group in the phenols was completely removed. A synergistic effect was found between lignin and LDPE. The proportion of aromatics increased and alkylated phenols decreased with increasing HZSM-5 to MgO ratio. The bio-oil yield increased with the addition of appropriate amount of catalyst and the proportion of alkylated phenols increased with increasing catalyst to feedstock ratio. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on flavonoid migration from active low-density polyethylene film into aqueous food simulants.

PubMed

Zhang, Shuangling; Zhao, Haiyan

2014-08-15

The migration of flavonoids from low-density polyethylene (LDPE) film (0.4%, w/w) to aqueous food simulants over 16 weeks at 0, 15, and 30 °C was investigated. The migration amount of total flavonoids was calculated based on the rutin contents determined by high-performance liquid chromatography (HPLC). Diffusion and partition coefficients, along with the activation energy (Ea) were calculated based on Fick's second law. The results showed that the migration of flavonoids was influenced by temperature, time and the simulants. The Ea values for flavonoid diffusion were 49.2, 55.9, and 25.8 kJ mol(-1) in distilled water, 4% acetic acid and 30% ethanol, respectively. This study indicated that the flavonoids in LDPE film easily migrated into food simulants; and this behaviour was related to the low Ea values of flavonoid diffusion, especially in ethanol at 0-30 °C, when the antioxidants were released from the film. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of Nanoparticles on the Morphology, Thermal, and Electrical Properties of Low-Density Polyethylene after Thermal Aging.

PubMed

Wang, Youyuan; Wang, Can; Zhang, Zhanxi; Xiao, Kun

2017-10-12

This paper investigates the morphology, thermal, and electrical properties of LDPE (low-density polyethylene)-based nanocomposites after thermal aging. The FTIR (Fourier transform infrared spectroscopy) spectra results show that thermo-oxidative reactions occur in neat LDPE and LDPE/SiO₂ nanocomposites when the aging time is 35 days and in LDPE/MgO nanocomposites when the aging time is 77 days. Specifically, LDPE/MgO nanocomposites delay the appearance of thermo-oxidative reactions, showing anti-thermal aging ability. Furthermore, nanocomposites present lower onset degradation temperature than neat LDPE, showing better thermal stabilization. With regard to the electrical properties, nanocomposites maintain the ability to suppress space charge accumulation after thermal aging. Additionally, in comparison with SiO₂ nanocomposites and neat LDPE, the permittivity of LDPE/MgO nanocomposites changes slightly after thermal aging. It is concluded that LDPE/MgO nanocomposites have better insulation properties than neat LDPE after thermal aging, which may be caused by the interface introduced by the nanoparticles.

ISTA 14-in-situ accumulation of PAHs in low-density polyethylene membranes in sediment.

PubMed

Devault, Damien A; Combe, Matthieu; Gourlay-Francé, Catherine

2010-10-01

The use of passive samplers for the assessment of organic contaminants has been extended to solid matrixes for the past decade. Passive sampling is usually applied to sediment in laboratory experiments involving significant upheaval, whereas in-situ experiments remain rare. In this study, low-density polyethylene (LDPE) strips were deployed within the sediments of a small river contaminated with polycyclic aromatic hydrocarbons (PAHs). LDPE strips were deployed in the 3-cm depth sediment layer. Over a period of 36 days, LDPE strips were regularly retrieved and accumulated PAHs in LDPE were extracted and analyzed. Accumulations of hydrophobic contaminants in LDPE directly exposed in the sediment were observed. Accumulations in LDPE were observed for moderately hydrophobic PAHs with the highest concentrations in the sediment. Low accumulations were observed for more hydrophobic compounds, despite their presence in high concentrations in the sediment. This was explained by very low exchange rates and competitive interactions with particles in the sediment. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Enhancement of in vitro high-density polyethylene (HDPE) degradation by physical, chemical, and biological treatments.

PubMed

Balasubramanian, V; Natarajan, K; Rajeshkannan, V; Perumal, P

2014-11-01

Partially degraded high-density polyethylene (HDPE) was collected from plastic waste dump yard for biodegradation using fungi. Of various fungi screened, strain MF12 was found efficient in degrading HDPE by weight loss and Fourier transform infrared (FT-IR) spectrophotometric analysis. Strain MF12 was selected as efficient HDPE degraders for further studies, and their growth medium composition was optimized. Among those different media used, basal minimal medium (BMM) was suitable for the HDPE degradation by strain MF12. Strain MF12 was subjected to 28S rRNA sequence analysis and identified as Aspergillus terreus MF12. HDPE degradation was carried out using combinatorial physical and chemical treatments in conjunction to biological treatment. The high level of HDPE degradation was observed in ultraviolet (UV) and KMnO4/HCl with A. terreus MF12 treatment, i.e., FT10. The abiotic physical and chemical factors enhance the biodegradation of HDPE using A. terreus MF12.

Microplastic pollution in the marine waters and sediments of Hong Kong.

PubMed

Tsang, Y Y; Mak, C W; Liebich, C; Lam, S W; Sze, E T-P; Chan, K M

2017-02-15

The presence of plastic waste with a diameter of less than 5mm ("microplastics") in marine environments has prompted increasing concern in recent years, both locally and globally. We conducted seasonal surveys of microplastic pollution in the surface waters and sediments from Deep Bay, Tolo Harbor, Tsing Yi, and Victoria Harbor in Hong Kong between June 2015 and March 2016. The average concentrations of microplastics in local coastal waters and sediments respectively ranged from 51 to 27,909particles per 100m 3 and 49 to 279particles per kilogram. Microplastics of different shapes (mainly fragments, lines, fibers, and pellets) were identified as polypropylene, low-density polyethylene, high-density polyethylene, a blend of polypropylene and ethylene propylene, and styrene acrylonitrile by means of Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy. This is the first comprehensive study to assess the spatial and temporal variations of microplastic pollution in Hong Kong coastal regions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Morphology-Property relationship of high density Polyethylene/Hevea Brasiliensis Leaves/Imperata cylindrica hybrid composite: Impact strength

NASA Astrophysics Data System (ADS)

Rashidi, A. R.; Muhammad, A.; Roslan, A.

2017-09-01

This research studies about the Hevea Brasiliensis Leaves and Imperata Cylindrica that was used as filler in High Density Polyethylene (HDPE). The fillers content were varied in the composite by 5 wt%, 15 wt% and 25 wt% respectively. This polymer composite are being studied by using Impact Test and Scanning Electron Microscopy (SEM). The analysis show that the impact strength value increased when the percent of bio filler used is low. The result between pure HDPE and the composites shows an outcome of significant changes in impact energy values, while the values between different composite change slightly. A composite that contained 5 wt% of fillers is the better energy absorber than 15 wt% and 25 wt% according to impact testing. In addition, the morphology studies on the composite sample show that the bio-filler was successfully embedded. Overall, these finding suggest that HBL and IC can be an alternative filler to be incorporated in polymer matrix.

Improvement of barrier properties of rotomolded PE containers with nanoclay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jamshidi, Shadi; Sundararaj, Uttandaraman, E-mail: u.sundararaj@ucalgary.ca

Polyethylene (PE) is widely used to make bulk containers in rotational molding process. The challenge in this study is to improve permeation resistance of PE to hydrocarbon solvents and gases. Adding organomodified clay improves the thermal, barrier and mechanical properties of PE. In fact, clay layers create a tortuous path against the permeant, yielding better barrier properties. Due to the non-polar hydrophobic nature of PE and polar hydrophilic structure of clay minerals, the compatibilizer plays a crucial role to enhance the dispersion level of clay in the matrix. In this study High Density Polyethylene (HDPE) and Linear Low Density Polyethylenemore » (LLDPE) layered silicate nanocomposite were melt-compounded with two concentrations of organomodified clay (2 and 4 wt. %). The interaction between nanoclay, compatibilizer and rotomolding grade of PE were examined by using X-ray diffraction, transmission electron microscopy (TEM) and rheology test. Rheology was used to determine the performance of our material at low shear processing condition.« less

Conformation and hydration of surface grafted and free polyethylene oxide chains in solutions

NASA Astrophysics Data System (ADS)

Dahal, Udaya; Wang, Zilu; Dormidontova, Elena

Due to the wide application of polyethylene oxide (PEO), ranging from biomedicine to fuel cells, it is one of the most studied polymers in the scientific world. In order to elucidate detailed molecular-level insights on the impact of surface grafting on PEO conformation, we performed atomistic molecular dynamics simulations of PEO chains in solution and grafted to a flat gold surface in different solvents. We examined the hydration as well as conformation of the free chain compared to the grafted polymer in pure water and mixed solvents. We find that grafted chains are stiffer and have a stronger tendency to form helical structures in isobutyric acid or mixture of isobutyric acid and water solution than the free chains in corresponding solutions. For grafted chains exposed to pure water the random coil conformation is retained at low grafting density, but becomes stretched and more dehydrated as the grafting density or temperature increases. This research is supported by NSF (DMR-1410928).

[Determination of solubility parameters of high density polyethylene by inverse gas chromatography].

PubMed

Wang, Qiang; Chen, Yali; Liu, Ruiting; Shi, Yuge; Zhang, Zhengfang; Tang, Jun

2011-11-01

Inverse gas chromatographic (IGC) technology was used to determine the solubility parameters of high density polyethylene (HDPE) at the absolute temperatures from 303.15 to 343.15 K. Six solvents were applied as test probes including hexane (n-C6), heptane (n-C7), octane (n-C8), nonane (n-C9), chloroform (CHCl3) and ethyl acetate (EtAc). Some thermodynamic parameters were obtained by IGC data analysis such as the specific retention volumes of the solvents (V(0)(g)), the molar enthalpy of sorption (delta H(S)(1)), the partial molar enthalpy of mixing at infinite dilution (delta H(1)(infinity)), the molar enthalpy of vaporization (delta H(v)), the activity coefficients at infinite dilution (omega (1)(infinity)), and Flow-Huggins interaction parameters (X(1,2)(infinity)) between HDPE and probe solvents. The results showed that the above six probes are poor solvents for HDPE. The solubility parameter of HDPE at room temperature (298.15 K) was also derived as 19.00 (J/cm3)(0.5).

Quantitative control of poly(ethylene oxide) surface antifouling and biodetection through azimuthally enhanced grating coupled-surface plasmon resonance sensing

NASA Astrophysics Data System (ADS)

Sonato, Agnese; Silvestri, Davide; Ruffato, Gianluca; Zacco, Gabriele; Romanato, Filippo; Morpurgo, Margherita

2013-12-01

Grating Coupled-Surface Plasmon reflectivity measurements carried out under azimuth and polarization control (GC-SPR φ ≠ 0°) were used to optimize the process of gold surface dressing with poly(ethylene oxide) (PEO) derivatives of different molecular weight, with the final goal to maximize the discrimination between specific and non-specific binding events occurring at the surface. The kinetics of surface deposition of thiol-ending PEOs (0.3, 2 and 5 kDa), introduced as antifouling layers, was monitored. Non-specific binding events upon immersion of the surfaces into buffers containing either 0.1% bovine serum albumin or 1% Goat Serum, were evaluated as a function of polymer size and density. A biorecognition event between avidin and biotin was then monitored in both buffers at selected low and high polymer surface densities and the contribution of analyte and fouling elements to the signal was precisely quantified. The 0.3 kDa PEO film was unable to protect the surface from non-specific interactions at any tested density. On the other hand, the 2 and 5 kDa polymers at their highest surface densities guaranteed full protection from non-specific interactions from both buffers. These densities were reached upon a long deposition time (24-30 h). The results pave the way toward the application of this platform for the detection of low concentration and small dimension analytes, for which both non-fouling and high instrumental sensitivity are fundamental requirements.

Molecular dynamics simulation study of the structure of poly(ethylene oxide) brushes on nonpolar surfaces in aqueous solution.

PubMed

Bedrov, Dmitry; Smith, Grant D

2006-07-04

The structure of poly(ethylene oxide) (PEO, M(w) = 526) brushes of various grafting density (sigma) on nonpolar graphite and hydrophobic (oily) surfaces in aqueous solution has been studied using atomistic molecular dynamics simulations. Additionally, the influence of PEO-surface interactions on the brush structure was investigated by systematically reducing the strength of the (dispersion) attraction between PEO and the surfaces. PEO chains were found to adsorb strongly to the graphite surface due primarily to the relative strength of dispersion interactions between PEO and the atomically dense graphite compared to those between water and graphite. For the oily surface, PEO-surface and water-surface dispersion interactions are much weaker, greatly reducing the energetic driving force for PEO adsorption. This reduction is mediated to some extent by a hydrophobic driving force for PEO adsorption on the oily surface. Reduction in the strength of PEO-surface attraction results in reduced adsorption of PEO for both surfaces, with the effect being much greater for the graphite surface where the strong PEO-surface dispersion interactions dominate. At high grafting density (sigma approximately 1/R(g)(2)), the PEO density profiles exhibited classical brush behavior and were largely independent of the strength of the PEO-surface interaction. With decreasing grafting density (sigma < 1/R(g)(2)), coverage of the surface by PEO requires an increasingly large fraction of PEO segments resulting in a strong dependence of the PEO density profile on the nature of the PEO-surface interaction.

UV light induced surface modification of HDPE films with bioactive compounds

NASA Astrophysics Data System (ADS)

Daniloska, Vesna; Blazevska-Gilev, Jadranka; Dimova, Vesna; Fajgar, Radek; Tomovska, Radmila

2010-01-01

The development of different techniques for surface modification of polymers becomes popular in a last decade. These techniques preserve useful bulk polymer properties unchanged, while the activation of the polymer surface offers more possibilities for polymer applications. In this work, a new, one-step method for bio-activation of HDPE (high density polyethylene) surface by UV irradiation is presented. HDPE films coupled with selected active compound and a photoinitiator was treated by UV lamp, emitting light at 254 nm. For surface functionalization of HDPE films, the following compounds were employed: 2-aminopyridine (AP), N 1-(2-pyridylaminomethyl)-1,2,4-triazole (TA) and benzocaine (BC). The influence of irradiation time on the extent of surface changes was investigated. The modified polymer surfaces were investigated by Fourier transformed infrared (FTIR) and Raman spectroscopy, scanning electron microscopy (SEM) and contact angle measurements, demonstrating successful functionalization of HDPE surface.

Influence of electron beam irradiation on the microrheology of incompatible polymer blends: Thread break-up and coalescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Gisbergen, J.G.M.; Meijer, H.E.H.

1991-01-01

The microrheology of polymer blends as influenced by crosslinks induced in the dispersed phase via electron beam irradiation, is systematically investigated for the model system polystyrene/low density polyethylene (PS/LDPE). Both break-up of threads and coalescence of particles are delayed to a large extent, but are not inhibited completely and occur faster than would be expected for a nonirradiated material with a comparable viscosity. Small amplitude, dynamic rheological measurements indicated that in the irradiated materials a yield stress could exist. In contrast, direct microrheological measurements showed that this yield stress, which would prevent both break-up and coalescence, could not be realizedmore » by EB irradiation. Apparently, the direct study of the microrheology of a blend system is important for the prediction of the development of its morphology and it is not possible to rely only on rheological data obtained via other methods.« less

Uranium plasma emission at gas-core reaction conditions

NASA Technical Reports Server (NTRS)

Williams, M. D.; Jalufka, N. W.; Hohl, F.; Lee, J. H.

1976-01-01

The results of uranium plasma emission produced by two methods are reported. For the first method a ruby laser was focused on the surface of a pure U-238 sample to create a plasma plume with a peak plasma density of about 10 to the 20th power/cu cm and a temperature of about 38,600 K. The absolute intensity of the emitted radiation, covering the range from 300 to 7000 A was measured. For the second method, the uranium plasma was produced in a 20 kilovolt, 25 kilojoule plasma-focus device. The 2.5 MeV neutrons from the D-D reaction in the plasma focus are moderated by polyethylene and induce fissions in the U-235. Spectra of both uranium plasmas were obtained over the range from 30 to 9000 A. Because of the low fission yield the energy input due to fissions is very small compared to the total energy in the plasma.

Polyethylene glycol grafted polyethylene: a versatile platform for nonmigratory active packaging applications.

PubMed

Barish, Jeffrey A; Goddard, Julie M

2011-01-01

Nonmigratory active packaging, in which bioactive components are tethered to the package, offers the potential to reduce the need for additives in food products while maintaining safety and quality. A challenge in developing nonmigratory active packaging materials is the loss of biomolecular activity that can occur when biomolecules are immobilized. In this work, we describe a method in which a biocompatible polymer (polyethylene glycol, PEG) is grafted from the surface of ozone-treated low-density polyethylene (LDPE) resulting in a surface functionalized polyethylene to which a range of amine-terminated bioactive molecules can be immobilized. Free radical graft polymerization is used to graft PEG onto the LDPE surface, followed by immobilization of ethylenediamine onto the PEG tether. Ethylenediamine was used to demonstrate that amine-terminated molecules could be covalently attached to the PEG-grafted film. Changes in surface chemistry and topography were measured by attenuated total reflectance Fourier transform infrared spectroscopy, contact angle, atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. We demonstrate the ability to graft PEG onto the surface of polymer packaging films by free radical graft polymerization, and to covalently link an amine-terminated molecule to the PEG tether, demonstrating that amine-terminated bioactive compounds (such as peptides, enzymes, and some antimicrobials) can be immobilized onto PEG-grafted LDPE in the development of nonmigratory active packaging.   Nonmigratory active packaging offers the potential for improving food safety and quality while minimizing the migration of the active agent into food. In this paper, we describe a technique to modify polyethylene packaging films such that active agents can be covalently immobilized by a biocompatible tether. Such a technique can be adapted to a number of applications such as antimicrobial, antioxidant, or immobilized enzyme active packaging. © 2011 Institute of Food Technologists®

Sensor capsule for diagnosis of gastric disorders

NASA Technical Reports Server (NTRS)

Holen, J. T.

1972-01-01

Motility and pH sensor capsule is developed to monitor gastric acidity, pressure, and temperature. Capsule does not interfere with digestion. Sensor is capsule which includes pH electrode, Pitran pressure transducer, and thermistor temperature sensor all potted in epoxy and enclosed in high density polyethylene sheath.

Measuring freely dissolved water concentrations of PCBs using LDPE passive samplers and performance reference compounds (PRCs)

EPA Science Inventory

Low-Density polyethylene (LDPE) sheets are often used as passive samplers for aquatic environmental monitoring to measure the dissolved concentrations of hydrophobic organic contaminants (HOCs). These concentrations are then used to evaluate the potential for ecological and human...

Research physic-mechanical properties of composite materials on the base of peeled veneer and low density polyethylene

NASA Astrophysics Data System (ADS)

Ibragimov, Aleksandr; Vasilkin, Andrey; Fedotov, Aleksandr

2017-10-01

Use film of LDPE as thermoplastic binder for production of plywood is proposed. Results of physic-mechanical properties of plywood based on the LDPE film of different thicknesses in comparison with conventional thermosetting synthetic binder are presented.

Material Science

NASA Image and Video Library

2003-02-09

Materials with a smaller mean atomic mass, such as lithium (Li) hydride and polyethylene, make the best radiation shields for astronauts. The materials have a higher density of nuclei and are better able to block incoming radiation. Also, they tend to produce fewer and less dangerous secondary particles after impact with incoming radiation.

Optimal Substitution of Cotton Burr and Linters in Thermoplastic Composites

USDA-ARS?s Scientific Manuscript database

A study was conducted to evaluate various substitutions of cotton burr and linters fractions of cotton gin waste (CGW) as a natural fiber source in ligno-cellulosic polymer composites (LCPC.) Samples were fabricated with approximately 50% natural fiber, 40% of high-density polyethylene (HDPE) powder...

Structural and magnetic characterization of copper sulfonated phthalocyanine grafted onto treated polyethylene

NASA Astrophysics Data System (ADS)

Reznickova, A.; Kolska, Z.; Orendac, M.; Cizmar, E.; Sajdl, P.; Svorcik, V.

2016-08-01

This study focuses on high density polyethylene (HDPE) activated by Ar plasma treatment, subsequently grafted with copper sulfonated phthalocyanine (CuPc) especially pointing out to the surface and magnetic properties of those composites. Properties of pristine PE and their plasma treated counterparts were studied by different experimental techniques: X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, zeta potential and by electron spin resonance (ESR). XPS analysis confirmed the successful grafting of phthalocyanine. The highest absorption was found for the sample grafted with bCuPc for 1 h. Electrokinetic analysis also confirmed the plasma treatment and also subsequent CuPc grafting influence significantly the surface chemistry and charge. These results correspond well with XPS determination. ESR studies confirmed the presence of CuPc grafted on HDPE. It was found, that grafting is mediated by magnetically inactive functional groups, rather than radicals. Magnetic properties of CuPc do not seem to change significantly after grafting CuPc on polyethylene surface.

Enhanced flashover strength in polyethylene nanodielectrics by secondary electron emission modification

NASA Astrophysics Data System (ADS)

Wang, Weiwang; Li, Shengtao; Min, Daomin

2016-04-01

This work studies the correlation between secondary electron emission (SEE) characteristics and impulse surface flashover in polyethylene nanodielectrics both theoretically and experimentally, and illustrates the enhancement of flashover voltage in low-density polyethylene (LDPE) through incorporating Al2O3 nanoparticles. SEE characteristics play key roles in surface charging and gas desorption during surface flashover. This work demonstrates that the presence of Al2O3 nanoparticles decreases the SEE coefficient of LDPE and enhances the impact energy at the equilibrium state of surface charging. These changes can be explained by the increase of surface roughness and of surface ionization energy, and the strong interaction between nanoparticles and the polymer dielectric matrix. The surface charge and flashover voltage are calculated according to the secondary electron emission avalanche (SEEA) model, which reveals that the positive surface charges are reduced near the cathode triple point, while the presence of more nanoparticles in high loading samples enhances the gas desorption. Consequently, the surface flashover performance of LDPE/Al2O3 nanodielectrics is improved.

Hydrogels of poly(ethylene glycol): mechanical characterization and release of a model drug.

PubMed

Iza, M; Stoianovici, G; Viora, L; Grossiord, J L; Couarraze, G

1998-03-02

Thermosensitive polymer networks were synthesized from poly(ethylene glycol), hexamethylene diisocyanate and 1,2,6-hexanetriol in stoichiometric proportions. By varying the amount of 1,2,6-hexanetriol and the molar mass of the poly(ethylene glycol), a wide range of networks with different crosslinking densities was prepared. The networks obtained were characterized by the temperature dependence of their degree of equilibrium swelling in water and by their Young's moduli. For each network, the molecular weight between crosslinks was estimated. The structure of the hydrogels was analysed with respect to scaling laws, and it was found that the results obtained with PEG 1500 and PEG 6000 hydrogels are in agreement with theoretical predictions, whereas those obtained with PEG 400 hydrogels are in disagreement. The release properties of PEG hydrogels were studied by the determination of the diffusion coefficient for acebutolol chlorhydrate and by an analysis of the effect of temperature on these coefficients. Finally, these release properties were correlated with the swelling and structural properties of the hydrogels.

Atomistic simulation of CO2 solubility in poly(ethylene oxide) oligomers

NASA Astrophysics Data System (ADS)

Hong, Bingbing; Panagiotopoulos, Athanassios Z.

2014-06-01

We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide) dimethyl ether, CH3O(CH2CH2O)nCH3 (PEO for short) is a widely applied physical solvent that forms the major organic constituent of a class of novel nanoparticle-based absorbents. Good predictions were obtained for pressure-composition-density relations for CO2 + PEO oligomers (2 ≤ n ≤ 12), using the Potoff force field for PEO [J. Chem. Phys. 136, 044514 (2012)] together with the TraPPE model for CO2 [AIChE J. 47, 1676 (2001)]. Water effects on Henry's constant of CO2 in PEO have also been investigated. Addition of modest amounts of water in PEO produces a relatively small increase in Henry's constant. Dependence of the calculated Henry's constant on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length.

Monitoring the petroleum bitumen characteristics changes during their interaction with the polymers

NASA Astrophysics Data System (ADS)

Belyaev, P. S.; Mishchenko, S. V.; Belyaev, V. P.; Frolov, V. A.

2017-08-01

The subject of the study is the characteristics (penetration, softening temperature, ductility and elasticity) of a road binder based on petroleum bitumen. The work purpose is to monitor the changes in the characteristics of petroleum bitumen when it interacting with polymers: thermoplastic elastomer, low-density polyethylene, including the adhesive additive presence. To carry out the research a special laboratory facility was designed and manufactured with two blade mixers providing intensive turbulent mixing and the possibility to effect on the transition process of combining the components in a polymer-bitumen binder. To construct a mathematical model of the polymer-bitumen binder characteristics dependence from the composition, methods of statistical experiments planning were used. The possibility of the expensive thermoplastic elastomers replacement with polyethylene is established while maintaining acceptable polymer-bitumen binder quality parameters. The obtained results are proposed for use in road construction. They allow to reduce the roads construction cost with solving the problem of recycling long-term waste packaging from polyethylene.

Research on the discharge characteristics for water tree in crosslinked polyethylene cable based on plasma-chemical model

NASA Astrophysics Data System (ADS)

Fan, Yang; Qi, Yang; Bing, Gao; Rong, Xia; Yanjie, Le; Iroegbu, Paul Ikechukwu

2018-03-01

Water tree is the predominant defect in high-voltage crosslinked polyethylene cables. The microscopic mechanism in the discharge process is not fully understood; hence, a drawback is created towards an effective method to evaluate the insulation status. In order to investigate the growth of water tree, a plasma-chemical model is developed. The dynamic characteristics of the discharge process including voltage waveform, current waveform, electron density, electric potential, and electric field intensity are analyzed. Our results show that the distorted electric field is the predominant contributing factor of electron avalanche formation, which inevitably leads to the formation of pulse current. In addition, it is found that characteristic parameters such as the pulse width and pulse number have a great relevance to the length of water tree. Accordingly, the growth of water tree can be divided into the initial stage, development stage, and pre-breakdown stage, which provides a reference for evaluating the deteriorated stages of crosslinked polyethylene cables.

Multiple Ion Implantation Effects on Wear and Wet Ability of Polyethylene Based Polymers

NASA Astrophysics Data System (ADS)

Torrisi, L.; Visco, A. M.; Campo, N.

2004-10-01

Polyethylene based polymers were ion implanted with multiple irradiations of different ions (N+, Ar+ and Kr+) at energies between 30 keV and 300 keV and doses ranging between 1013 and 1016 ions/cm2. The ion implantation dehydrogenises the polyethylene inducing cross-link effects in the residual polymer carbons. At high doses the irradiated surface show properties similar to graphite surfaces. The depth of the modified layers depends on the ion range in polyethylene at the incident ion energy. The chemical modification depends on the implanted doses and on the specie of the incident ions. A "pin-on-disc" machine was employed to measure the polymer wear against AISI-316 L stainless steel. A "contact-angle-test" machine was employed to measure the wet ability of the polymer surface for 1 μl pure water drop. Measurements demonstrate that the multiple ion implantation treatments decrease the surface wear and the surface wetting and produce a more resistant polymer surface. The properties of the treated surfaces improves the polymer functionality for many bio-medical applications, such as those relative to the polyethylene friction discs employed in knee and hip prosthesis joints. The possibility to use multiply ion implantations of polymers with traditional ion implanters and with laser ion sources producing plasmas is investigated.

[Mobility of a polyethylene tibial insert in a mobile total knee prosthesis].

PubMed

Castel, E; Roger, B; Camproux, A; Saillant, G

1999-03-01

We have studied the mobility of a mobile tibial implant in total knee arthroplasty (TKA) by a radiographical evaluation. We analyzed mobility of the polyethylene tibial insert of 15 "G2S" TKA implanted for one year or more. We established a dynamic radiographical evaluation. We used 3 weight-bearing radiographs: AP in extension and two lateral (one in extension and one at 90 degrees of flexion), two AP with femoral internal and external rotation, 2 strict lateral X-rays in neutral rotation in antero-posterior replacement with a 25 kilograms strength Telos, and 2 AP in varus and valgus with Telos. Wilcoxon's test and Fisher's exact test were used for statistical evaluation. Our study demonstrated preservation of the polyethylene mobility in tibial TKA implant in all movements: in rotation, in antero-posterior translation with Telos, and even in antero-posterior translation during physiological condition with flexion-extension weight-bearing radiographs. Statistical tests were very significant. We noticed that flexion induced anterior translation of tibial polyethylene when PCL was preserved. This study answered to our question whether mobility of TKA tibial implant persists after implantation. This mobility should reduce loosening forces to the tibia and stress in the polyethylene component. Now we have to determine the amplitude of mobility required to reach this objective.

Formation, Structure and Electrochemical Impedance Analysis of Microporous Polyelectrolyte Multilayers

NASA Astrophysics Data System (ADS)

Lutkenhaus, Jodie; McEnnis, Kathleen; Hammond, Paula

2007-03-01

Microporous networks are of interest as electrolyte materials, gas separation membranes and catalytic nanoparticle templates. Here, we create microporous polyelectrolyte networks of tunable pore size and connectivity using the layer-by-layer (LBL) technique. In this method, a film is formed from the alternate adsorption of oppositely charged polyelectrolytes from aqueous solution to create a cohesive thin film. Using poly(ethylene imine) (PEI) and poly(acrylic acid) (PAA), LBL thin films of variable composition and charge density were assembled; then, the films were treated in an acidic bath, which ionizes PEI and de-ionizes PAA. This shift in charge density induces morphological rearrangement realized by a microporous network. Depending on the assembly pH and acidic bath pH, we are able to precisely tune the morphology, which is characterized by atomic force microscopy and scanning electron microscopy. To demonstrate the porous nature of the polyelectrolyte multilayer, the pores were filled with non-aqueous electrolyte (i.e. ethylene carbonate, dimethyl carbonate and lithium hexafluorophosphate) and probed with electrochemical impedance spectroscopy. These microporous networks exhibited two time constants, indicative of ions traveling through the liquid-filled pores and ions traveling through the polyelectrolyte matrix.

Temperature increase and charging current in polyethylene film during application of high voltage

NASA Astrophysics Data System (ADS)

Zhang, Chao; Kaneko, Kazue; Mizutani, Teruyoshi

2001-12-01

Temperature increase in a low density polyethylene film during the application of high dc voltage was estimated by measuring the sound velocity with a pulsed electroacoustic method. The temperature shows no change under the electric field of 50 MVm-1 at ambient temperature of 30 °C. However, the temperature increases with time, and rises to 63.7 °C in 90 min of the voltage application at ambient temperature of 60 °C. The temperature increase was caused by Joule heating and it resulted in the increase of charging current during the application of high dc voltage. The increase in charging current calculated from the temperature increase agreed well with the experimental one.

Investigation on electrical tree propagation in polyethylene based on etching method

NASA Astrophysics Data System (ADS)

Shi, Zexiang; Zhang, Xiaohong; Wang, Kun; Gao, Junguo; Guo, Ning

2017-11-01

To investigate the characteristic of electrical tree propagation in semi-crystalline polymers, the low-density polyethylene (LDPE) samples containing electrical trees are cut into slices by using ultramicrotome. Then the slice samples are etched by potassium permanganate etchant. Finally, the crystalline structure and the electrical tree propagation path in samples are observed by polarized light microscopy (PLM). According to the observation, the LDPE spherocrystal structure model is established on the basis of crystallization kinetics and morphology of polymers. And the electrical tree growth process in LDPE is discussed based on the free volume breakdown theory, the molecular chain relaxation theory, the electromechanical force theory, the thermal expansion effect and the space charge shielding effect.

Electrospun Polyaniline/Polyethylene Oxide Nanofiber Field Effect Transistor

NASA Technical Reports Server (NTRS)

Pinto, N. J.; Johnson, A. T.; MacDiarmid, A. G.; Mueller, C. H.; Theofylaktos, N.; Robinson, D. C.; Miranda, F. A.

2003-01-01

We report on the observation of field effect transistor (FET) behavior in electrospun camphorsulfonic acid doped polyaniline(PANi)/polyethylene oxide(PE0) nanofibers. Saturation channel currents are observed at surprisingly low source/drain voltages. The hole mobility in the depletion regime is 1.4 x 10(exp -4) sq cm/V s while the 1-D charge density (at zero gate bias) is calculated to be approximately 1 hole per 50 two-ring repeat units of polyaniline, consistent with the rather high channel conductivity (approx. 10(exp -3) S/cm). Reducing or eliminating the PEO content in the fiber is expected to enhance device parameters. Electrospinning is thus proposed as a simple method of fabricating 1-D polymer FET's.

Molecular Dynamics Simulations of Strain-Induced Phase Transition of Poly(ethylene oxide) in Water.

PubMed

Donets, Sergii; Sommer, Jens-Uwe

2018-01-11

We study the dilute aqueous solutions of poly(ethylene oxide) (PEO) oligomers that are subject to an elongating force dipole acting on both chain ends using atomistic molecular dynamics. By increasing the force, liquid-liquid demixing can be observed at room temperature far below the lower critical solution temperature. For forces above 35 pN, fibrillar nanostructures are spontaneously formed related to a decrease in hydrogen bonding between PEO and water. Most notable is a rapid decrease in the bifurcated hydrogen bonds during stretching, which can also be observed for isolated single chains. The phase-segregated structures display signs of chain ordering, but a clear signature of the crystalline order is not obtained during the simulation time, indicating a liquid-liquid phase transition induced by chain stretching. Our results indicate that the solvent quality of the aqueous solution of PEO depends on the conformational state of the chains, which is most likely related to the specific hydrogen-bond-induced solvation of PEO in water. The strain-induced demixing of PEO opens the possibility to obtain polymer fibers with low energy costs because crystallization starts via the strain-induced demixing in the extended state only.

Fundamental investigations of clay/polymer nanocomposites and applications in co-extruded microlayered systems

NASA Astrophysics Data System (ADS)

Decker, Jeremy John

The second and fourth generations of hydroxylated dendritic polyesters (HBP2, HBP4) were combined with unmodified sodium montmorillonite clay (Na +MMT) in water to generate a broad range of polymer clay nanocomposites from 0 to 100% wt/wt Na+MMT. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to investigate intercalation states of the clay galleries. It was shown that interlayer spacings were independent of generation number and changed over the composition range from 0.5 nm to 3.5 nm in 0.5 nm increments that corresponded to a flattened HBP conformation within the clay tactoids. The HBP4/Na+MMT systems were investigated to study the vitrified Rigid Amorphous Fraction (RAF) induced by the clay surfaces. Differential Scanning Calorimetry (DSC) showed changes in heat capacity, Delta Cp, at Tg, that decreased with clay content, until completely suppressed at 80 wt% Na+MMT due to confinement. RAF was quantified from these changes in heat capacity and verified by the analysis of orthopositronium lifetime temperature scans utilizing positron annihilation lifetime spectroscopy (PALS): verifying the glassy nature of the RAF at elevated temperatures. Mathematical relationships allowed for correlation of the interlayer spacings with DeltaC p. RAF formation correlated to intercalated HBP4, and external surfaces of the clay tactoids. The interdiffusion of a polymer pair in microlayers was exploited to increase the concentration of nanoclay particles. When microlayers of a nanocomposite composed of organically modified montmorillonite (M2(HT)2 ) inside maleic anhydride grafted linear low-density polyethylene (LLDPE-g-MA) and low-density polyethylene (LDPE) were taken into the melt, the greater mobility of the linear LLDPE-g-MA chains compared to the branched LDPE chains caused shrinkage of the nanocomposite microlayers, concentrating the M 2(HT)2 contained within. Analysis of the clay morphology within these layers demonstrated an increase in clay particle lengths and aspect ratios, which was attributed to the growth of skewed aggregates during concentration. The melt induced clay concentration and increased clay particle dimensions caused significant decreases in the permeability of the nanocomposite microlayers and reduced the overall permeability of the multilayered films. Morphology and transport behavior of these microlayered films were compared to a series of bulk nanocomposites using a second LLDPE-g-MA containing M 2(HT)2 with varying clay content.

Low-density polyethylene films treated by an atmospheric Ar-O2 post-discharge: functionalization, etching, degradation and partial recovery of the native wettability state

NASA Astrophysics Data System (ADS)

Abou Rich, S.; Dufour, T.; Leroy, P.; Nittler, L.; Pireaux, J. J.; Reniers, F.

2014-02-01

To optimize the adhesion of layers presenting strong barrier properties on low-density polyethylene (LDPE) surfaces, we investigated the influence of argon and argon-oxygen atmospheric pressure post-discharges. This study was performed using x-ray photoelectron spectroscopy, atomic force microscopy, optical emission spectroscopy (OES) and dynamic water contact angle (WCA) measurements. After the plasma treatment, a slight increase in the roughness was emphasized, more particularly for the samples treated in a post-discharge supplied in oxygen. Measurements of the surface roughness and of the oxygen surface concentration suggested the competition of two processes playing a role on the surface hydrophilicity and occurring during the post-discharge treatment: the etching and the activation of the surface. The etching rate was estimated to about 2.7 nm s-1 and 5.8 nm s-1 for Ar and Ar-O2 post-discharges, respectively. The mechanisms underlying this etching were investigated through experiments, in which we discuss the influence of the O2 flow rate and the distance (gap) separating the plasma torch from the LDPE surface located downstream. O atoms and NO molecules (emitting in the UV range) detected by OES seem to be good candidates to explain the etching process. An ageing study is also presented to evidence the stability of the treated surfaces over 60 days. After 60 days of storage, we showed that whatever the O2 flow rate, the treated films registered a loss of their hydrophilic state since their WCA increased towards a common threshold of 80°. This ‘hydrophobic recovery’ effect was mostly attributed to the reorientation of induced polar chemical groups into the bulk of the material. Indeed, the relative concentrations of the carbonyl and carboxyl groups at the surface decreased with the storage time and seemed to reach a plateau after 30 days.

Low-cost optical fabrication of flexible copper electrode via laser-induced reductive sintering and adhesive transfer

NASA Astrophysics Data System (ADS)

Back, Seunghyun; Kang, Bongchul

2018-02-01

Fabricating copper electrodes on heat-sensitive polymer films in air is highly challenging owing to the need of expensive copper nanoparticles, rapid oxidation of precursor during sintering, and limitation of sintering temperature to prevent the thermal damage of the polymer film. A laser-induced hybrid process of reductive sintering and adhesive transfer is demonstrated to cost-effectively fabricate copper electrode on a polyethylene film with a thermal resistance below 100 °C. A laser-induced reductive sintering process directly fabricates a high-conductive copper electrode onto a glass donor from copper oxide nanoparticle solution via photo-thermochemical reduction and agglomeration of copper oxide nanoparticles. The sintered copper patterns were transferred in parallel to a heat-sensitive polyethylene film through self-selective surface adhesion of the film, which was generated by the selective laser absorption of the copper pattern. The method reported here could become one of the most important manufacturing technologies for fabricating low-cost wearable and disposable electronics.

Measurement and Ranking of Permeation Specimen Thickness Profiles: High-Density Polyethylene Swatches

DTIC Science & Technology

2016-05-01

6 3.2 Thickness Comparison between Lube-Cooled and No-Lube Techniques: Non- Welded ...14 3.3 Measured Thickness of Permeation Specimens: Non- Welded ........................16 3.4 Plots of Specimen Measurement Position...versus Thickness ...........................21 3.5 Measured Thickness of Permeation Specimens: Welded ................................23 4

A Field Evaluation of Performance Reference Compound Based Estimates of Cfree Using Water Column Deployed Passive Samplers

EPA Science Inventory

Low-Density polyethylene (LDPE) sheets are often used as passive samplers for aquatic environmental monitoring to measure the freely dissolved concentrations of hydrophobic organic contaminants (HOCs). HOCs that are freely dissolved in water (Cfree) will partition into the LDPE u...

Rolled cotton mulch as an alternative mulching material for transplanted cucurbit crops

USDA-ARS?s Scientific Manuscript database

Low-density polyethylene (LDPE) mulch is commonly used in transplanted vegetable crop production in the southeastern U. S. Cantaloupe and watermelon growers use a system of hybrid transplants, grown on narrow LDPE mulch-covered seedbeds with overhead irrigation, and use the mulch cover for only one...

Vegetable Response to Herbicides Applied to Low-Density Polyethylene Mulch Prior to Transplant

USDA-ARS?s Scientific Manuscript database

Few herbicides are available for weed control in vegetables. The elimination of methyl bromide increases the need for herbicides. An experiment was conducted to evaluate crop injury from herbicides applied to LDPE mulch prior to transplant. Irrigation (1 cm) or no irrigation following crop transplan...

Evaluation of non-fumigant pesticides as methyl bromide alternatives for managing weeds in vegetables

USDA-ARS?s Scientific Manuscript database

The phase out of methyl bromide challenged vegetable growers’ abilities to control weeds in low-density polyethylene (LDPE) mulch production systems. The herbicides halosulfuron, fomesafen, s-metolachlor, and clomazone are needed as part of the pesticide program in LDP vegetable production to contr...

Waste cotton as a biodegradable mulching material for transplanted watermelon and cantaloupe production

USDA-ARS?s Scientific Manuscript database

Low-density polyethylene (LDPE) mulch is commonly used in transplanted vegetable crop production in the southeastern U. S. Cantaloupe and watermelon growers use a system of hybrid transplants, grown on narrow LDPE mulch-covered seedbeds with overhead irrigation, and use the mulch cover for only one...

Qualification Testing of the SmartVault Household Goods Shipping Container

DTIC Science & Technology

2011-01-06

base with 4-way forklift entry and molded high-density polyethylene (HDPE) ribbed walls and ( translucent ) lid which are held together with stainless...and four edge drops of the container onto a smooth concrete surface (Appendix 2, Figure 22). The container was visually inspected for damage

Impact of biofibers and coupling agents on the weathering characteristics of composites polymer degradation and stability

USDA-ARS?s Scientific Manuscript database

This paper explores the ultraviolet (UV) weathering performance of high density polyethylene (HDPE) composites with different biofiber fillers and coupling agent. Biofiber polymer composite (BFPC) material samples were prepared using oak, cotton burr and stem (CBS) or guayule bagasse as fiber source...

Evaluating the precision of passive sampling methods using PRCs in the water column.

EPA Science Inventory

To assess these models, four different thicknesses of low-density polyethylene (LDPE) passive samplers were co-deployed for 28 days in the water column at three sites in New Bedford Harbor, MA, USA. Each sampler was pre-loaded with six PCB performance reference compounds (PRCs) t...

Measuring Viscoelastic Deformation with an Optical Mouse

ERIC Educational Resources Information Center

Ng, T. W.

2004-01-01

The feasibility of using an optical mouse to track the viscoelastic deformation of low-density polyethylene films that have a fixed attached load is presented. It is seen that using an optical mouse and with rudimentary experiment paraphernalia and arrangement, it is possible to get good measurements of viscoelastic deformation.

Performance of composite sand cement brick containing recycle concrete aggregate and waste polyethylene terephthalate with different mix design ratio

NASA Astrophysics Data System (ADS)

Azmi, N. B.; Khalid, F. S.; Irwan, J. M.; Mazenan, P. N.; Zahir, Z.; Shahidan, S.

2018-04-01

This study is focuses to the performance of composite sand cement brick containing recycle concrete aggregate and waste polyethylene terephthalate. The objective is to determine the mechanical properties such as compressive strength and water absorption of composite brick containing recycled concrete aggregate and polyethylene terephthalate waste and to determine the optimum mix ratio of bricks containing recycled concrete aggregate and polyethylene terephthalate waste. The bricks specimens were prepared by using 100% natural sand, they were then replaced by RCA at 25%, 50% and 75% with proportions of PET consists of 1.0%, 1.5%, 2.0% and 2.5% by weight of natural sand. Based on the results of compressive strength, it indicates that the replacement of RCA shows an increasing strength as the strength starts to increase from 25% to 50% for both mix design ratio. The strength for RCA 75% volume of replacement started to decrease as the volume of PET increase. However, the result of water absorption with 50% RCA and 1.0% PET show less permeable compared to control brick at both mix design ratio. Thus, one would expect the density of brick decrease and the water absorption to increase as the RCA and PET content is increased.

Bio-electrochemical characterization of air-cathode microbial fuel cells with microporous polyethylene/silica membrane as separator.

PubMed

Kircheva, Nina; Outin, Jonathan; Perrier, Gérard; Ramousse, Julien; Merlin, Gérard; Lyautey, Emilie

2015-12-01

The aim of this work was to study the behavior over time of a separator made of a low-cost and non-selective microporous polyethylene membrane (RhinoHide®) in an air-cathode microbial fuel cell with a reticulated vitreous carbon foam bioanode. Performances of the microporous polyethylene membrane (RhinoHide®) were compared with Nafion®-117 as a cationic exchange membrane. A non-parametric test (Mann-Whitney) done on the different sets of coulombic or energy efficiency data showed no significant difference between the two types of tested membrane (p<0.05). Volumetric power densities were ranging from 30 to 90 W·m(-3) of RVC foam for both membranes. Similar amounts of biomass were observed on both sides of the polyethylene membrane illustrating bacterial permeability of this type of separator. A monospecific denitrifying population on cathodic side of RhinoHide® membrane has been identified. Electrochemical impedance spectroscopy (EIS) was used at OCV conditions to characterize electrochemical behavior of MFCs by equivalent electrical circuit fitted on both Nyquist and Bode plots. Resistances and pseudo-capacitances from EIS analyses do not differ in such a way that the nature of the membrane could be considered as responsible. Copyright © 2015 Elsevier B.V. All rights reserved.

Investigation of the interaction of copper(II) oxide and electron beam irradiation crosslinkable polyethylene

NASA Astrophysics Data System (ADS)

Bee, Soo-Tueen; Sin, Lee Tin; Ratnam, C. T.; Haraveen, K. J. S.; Tee, Tiam-Ting; Rahmat, A. R.

2015-10-01

In this study, the effects of electron beam irradiation on the properties of copper(II) oxide when added to low-density polyethylene (LDPE) blends were investigated. It was found that the addition of low loading level of copper(II) oxide (⩽2 phr) to LDPE results in significantly poorer gel content and hot set results. However, the incorporation of higher loading level of copper(II) oxide (⩾3 phr) could slightly increase the degree of crosslinking in all irradiated LDPE composites. This is due to the fact that higher amounts of copper(II) oxide could slightly induce the formation of free radicals in LDPE matrix. Besides, increasing irradiation doses was also found to gradually increase the gel content of LDPE composites by generating higher amounts of free radicals. As a consequence, these higher amounts of free radicals released in the LDPE matrix could significantly increase the degree of crosslinking. The addition of copper(II) oxide could reduce the tensile strength and fracture strain (elongation at break) of LDPE composites because of poorer interfacial adhesion effect between copper(II) oxide particles and LDPE matrix. Meanwhile, increasing irradiation doses on all copper(II) oxide added LDPE composites could marginally increase the tensile strength. In addition, increasing irradiation dose could enhance the thermal stability of LDPE composites by increasing the decomposition temperature. The oxidation induction time (OIT) analysis showed that, because of the crosslinking network in the copper(II) oxide added LDPE composites, oxidation reaction is much delayed.

Orthopaedic wear particle-induced bone loss and exogenous macrophage infiltration is mitigated by local infusion of NF-κB decoy oligodeoxynucleotide.

PubMed

Lin, Tzuhua; Pajarinen, Jukka; Nabeshima, Akira; Córdova, Luis A; Loi, Florence; Gibon, Emmanuel; Lu, Laura; Nathan, Karthik; Jämsen, Eemeli; Yao, Zhenyu; Goodman, Stuart B

2017-11-01

Excessive production of wear particles from total joint replacements induces chronic inflammation, macrophage infiltration, and consequent bone loss (periprosthetic osteolysis). This inflammation and bone remodeling are critically regulated by the transcription factor NF-κB. We previously demonstrated that inhibition of NF-κB signaling by using the decoy oligodeoxynucleotide (ODN) mitigates polyethylene wear particle-induced bone loss using in vitro and in vivo models. However, the mechanisms of NF-κB decoy ODN action, and in particular its impact on systemic macrophage recruitment, remain unknown. In the current study, this systemic macrophage infiltration was examined in our established murine femoral continuous particle infusion model. RAW264.7 murine macrophages expressing a luciferase reporter gene were injected into the systemic circulation. Quantification of bioluminescence showed that NF-κB decoy ODN reduced the homing of these reporter macrophages into the distal femurs exposed to continuous particle delivery. Particle-induced reduction in bone mineral density at the distal diaphysis of the femur was also mitigated by infusion of decoy ODN. Histological staining showed that the decoy ODN infusion decreased osteoclast and macrophage numbers, but had no significant effects on osteoblasts. Local infusion of NF-κB decoy ODN reduced systemic macrophage infiltration and mitigated particle-induced bone loss, thus providing a potential strategy to treat periprosthetic osteolysis. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3169-3175, 2017. © 2017 Wiley Periodicals, Inc.

Long-term sorption of metals is similar among plastic types: implications for plastic debris in aquatic environments.

PubMed

Rochman, Chelsea M; Hentschel, Brian T; Teh, Swee J

2014-01-01

Concerns regarding plastic debris and its ability to accumulate large concentrations of priority pollutants in the aquatic environment led us to quantify relationships between different types of mass-produced plastic and metals in seawater. At three locations in San Diego Bay, we measured the accumulation of nine targeted metals (aluminum, chromium, manganese, iron, cobalt, nickel, zinc, cadmium and lead) sampling at 1, 3, 6, 9 and 12 months, to five plastic types: polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), and polypropylene (PP). Accumulation patterns were not consistent over space and time, and in general all types of plastic tended to accumulate similar concentrations of metals. When we did observe significant differences among concentrations of metals at a single sampling period or location in San Diego Bay, we found that HDPE typically accumulated lesser concentrations of metals than the other four polymers. Furthermore, over the 12-month study period, concentrations of all metals increased over time, and chromium, manganese, cobalt, nickel, zinc and lead did not reach saturation on at least one plastic type during the entire 12-month exposure. This suggests that plastic debris may accumulate greater concentrations of metals the longer it remains at sea. Overall, our work shows that a complex mixture of metals, including those listed as priority pollutants by the US EPA (Cd, Ni, Zn and Pb), can be found on plastic debris composed of various plastic types.

Comparison of bioreactors with different kinds of submerged packed beds for domestic wastewater treatment.

PubMed

Nacheva, P Mijaylova; Moeller Chávez, G; Bustos, C; Garzón Zúñiga, M A; Hornelas Orozco, Y

2008-01-01

The performance of aerobic submerged packed bed reactors was studied for the treatment of domestic wastewater using different kinds of packing materials with high specific areas (760-1,200 m(2)/m(3)). The tested materials were ceramic spheres, crushed tezontle, grains of high density polyethylene (HDPE), of low density polyethylene (LDPE) and of polypropylene (PP), cubes of polyurethane (PU) and polyethylene tape (SESSIL). The bioreactors were operated in continuous regime, applying organic loads in the range of 0.8-6.0 g COD.m(-2).d(-1). The obtained specific COD removal rates were very similar in all the reactors when they were operated at organic loads up to 2.0 g COD.m(-2).d(-1), after which differences in effectiveness appeared and the best results were determined in the reactors with SESSIL, LDPE and PU. Very low TSS, O&G and turbidity were obtained in all the effluents. The NH(3)-N and TN removals were dependent on the dissolved oxygen (DO) concentration and the removals at DO of 5 mg/l were 84-99% and 61-74% respectively. The best removals were determined in the reactors with PU, SESSIL and LDPE. The reactor with tezontle had also a good performance when operated with loads up to 1.0 g TN.m(-2).d(-1). The best phosphate removals (38-49%) were obtained in the reactors with PU, tezontle, ceramic sheres and SESSIL. (c) IWA Publishing 2008.

Long-Term Sorption of Metals Is Similar among Plastic Types: Implications for Plastic Debris in Aquatic Environments

PubMed Central

Rochman, Chelsea M.; Hentschel, Brian T.; Teh, Swee J.

2014-01-01

Concerns regarding plastic debris and its ability to accumulate large concentrations of priority pollutants in the aquatic environment led us to quantify relationships between different types of mass-produced plastic and metals in seawater. At three locations in San Diego Bay, we measured the accumulation of nine targeted metals (aluminum, chromium, manganese, iron, cobalt, nickel, zinc, cadmium and lead) sampling at 1, 3, 6, 9 and 12 months, to five plastic types: polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), and polypropylene (PP). Accumulation patterns were not consistent over space and time, and in general all types of plastic tended to accumulate similar concentrations of metals. When we did observe significant differences among concentrations of metals at a single sampling period or location in San Diego Bay, we found that HDPE typically accumulated lesser concentrations of metals than the other four polymers. Furthermore, over the 12-month study period, concentrations of all metals increased over time, and chromium, manganese, cobalt, nickel, zinc and lead did not reach saturation on at least one plastic type during the entire 12-month exposure. This suggests that plastic debris may accumulate greater concentrations of metals the longer it remains at sea. Overall, our work shows that a complex mixture of metals, including those listed as priority pollutants by the US EPA (Cd, Ni, Zn and Pb), can be found on plastic debris composed of various plastic types. PMID:24454866

Rapid discrimination of plastic packaging materials using MIR spectroscopy coupled with independent components analysis (ICA).

PubMed

Kassouf, Amine; Maalouly, Jacqueline; Rutledge, Douglas N; Chebib, Hanna; Ducruet, Violette

2014-11-01

Plastic packaging wastes increased considerably in recent decades, raising a major and serious public concern on political, economical and environmental levels. Dealing with this kind of problems is generally done by landfilling and energy recovery. However, these two methods are becoming more and more expensive, hazardous to the public health and the environment. Therefore, recycling is gaining worldwide consideration as a solution to decrease the growing volume of plastic packaging wastes and simultaneously reduce the consumption of oil required to produce virgin resin. Nevertheless, a major shortage is encountered in recycling which is related to the sorting of plastic wastes. In this paper, a feasibility study was performed in order to test the potential of an innovative approach combining mid infrared (MIR) spectroscopy with independent components analysis (ICA), as a simple and fast approach which could achieve high separation rates. This approach (MIR-ICA) gave 100% discrimination rates in the separation of all studied plastics: polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS) and polylactide (PLA). In addition, some more specific discriminations were obtained separating plastic materials belonging to the same polymer family e.g. high density polyethylene (HDPE) from low density polyethylene (LDPE). High discrimination rates were obtained despite the heterogeneity among samples especially differences in colors, thicknesses and surface textures. The reproducibility of the proposed approach was also tested using two spectrometers with considerable differences in their sensitivities. Discrimination rates were not affected proving that the developed approach could be extrapolated to different spectrometers. MIR combined with ICA is a promising tool for plastic waste separation that can help improve performance in this field; however further technological improvements and developments are required before it can be applied at an industrial level given that all tests presented here were performed under laboratory conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

How Low Can You Go? Low Densities of Poly(ethylene glycol) Surfactants Attract Stealth Proteins.

PubMed

Seneca, Senne; Simon, Johanna; Weber, Claudia; Ghazaryan, Arthur; Ethirajan, Anitha; Mailaender, Volker; Morsbach, Svenja; Landfester, Katharina

2018-06-25

It is now well-established that the surface chemistry and "stealth" surface functionalities such as poly(ethylene glycol) (PEG) chains of nanocarriers play an important role to decrease unspecific protein adsorption of opsonizing proteins, to increase the enrichment of specific stealth proteins, and to prolong the circulation times of the nanocarriers. At the same time, PEG chains are used to provide colloidal stability for the nanoparticles. However, it is not clear how the chain length and density influence the unspecific and specific protein adsorption keeping at the same time the stability of the nanoparticles in a biological environment. Therefore, this study aims at characterizing the protein adsorption patterns depending on PEG chain length and density to define limits for the amount of PEG needed for a stealth effect by selective protein adsorption as well as colloidal stability during cell experiments. PEG chains are introduced using the PEGylated Lutensol AT surfactants, which allow easy modification of the nanoparticle surface. These findings indicate that a specific enrichment of stealth proteins already occurs at low PEG concentrations; for the decrease of unspecific protein adsorption and finally the colloidal stability a full surface coverage is advised. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physicochemical Properties of Glycine-Based Ionic Liquid [QuatGly-OEt][EtOSO3] (2-Ethoxy-1-ethyl-1,1-dimethyl-2-oxoethanaminium ethyl sulfate) and Its Binary Mixtures with Poly(ethylene glycol) (Mw = 200) at Various Temperatures

PubMed Central

Wu, Tzi-Yi; Chen, Bor-Kuan; Hao, Lin; Lin, Yuan-Chung; Wang, H. Paul; Kuo, Chung-Wen; Sun, I-Wen

2011-01-01

This work includes specific basic characterization of synthesized glycine-based Ionic Liquid (IL) [QuatGly-OEt][EtOSO3] by NMR, elementary analysis and water content. Thermophysical properties such as density, ρ, viscosity, η, refractive index, n, and conductivity, κ, for the binary mixture of [QuatGly-OEt][EtOSO3] with poly(ethylene glycol) (PEG) [Mw = 200] are measured over the whole composition range. The temperature dependence of density and dynamic viscosity for neat [QuatGly-OEt][EtOSO3] and its binary mixture can be described by an empirical polynomial equation and by the Vogel-Tammann-Fucher (VTF) equation, respectively. The thermal expansion coefficient of the ILs is ascertained using the experimental density results, and the excess volume expansivity is evaluated. The negative values of excess molar volume for the mixture indicate the ion-dipole interactions and packing between IL and PEG oligomer. The results of binary excess property (VmE ) and deviations (Δη, Δxn, ΔΨn, ΔxR, and ΔΨR) are discussed in terms of molecular interactions and molecular structures in the binary mixture. PMID:22272102

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

NASA Astrophysics Data System (ADS)

Asriza, Ristika O.; Arcana, I. Made

2015-09-01

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm-1 indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asriza, Ristika O.; Arcana, I Made, E-mail: arcana@chem.itb.ac.id

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of themore » absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.« less

Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress

PubMed Central

Rochman, Chelsea M.; Hoh, Eunha; Kurobe, Tomofumi; Teh, Swee J.

2013-01-01

Plastic debris litters aquatic habitats globally, the majority of which is microscopic (< 1 mm), and is ingested by a large range of species. Risks associated with such small fragments come from the material itself and from chemical pollutants that sorb to it from surrounding water. Hazards associated with the complex mixture of plastic and accumulated pollutants are largely unknown. Here, we show that fish, exposed to a mixture of polyethylene with chemical pollutants sorbed from the marine environment, bioaccumulate these chemical pollutants and suffer liver toxicity and pathology. Fish fed virgin polyethylene fragments also show signs of stress, although less severe than fish fed marine polyethylene fragments. We provide baseline information regarding the bioaccumulation of chemicals and associated health effects from plastic ingestion in fish and demonstrate that future assessments should consider the complex mixture of the plastic material and their associated chemical pollutants. PMID:24263561

Measurements of the temperature dependence of radiation induced conductivity in polymeric dielectrics

NASA Astrophysics Data System (ADS)

Gillespie, Jodie

This study measures Radiation Induced Conductivity (RIC) in five insulating polymeric materials over temperatures ranging from ~110 K to ~350 K: polyimide (PI or Kapton HN(TM) and Kapton E(TM)), polytetraflouroethylene (PTFE or Teflon(TM)), ethylene-tetraflouroethylene (ETFE or Tefzel(TM)), and Low Density Polyethylene (LDPE). RIC occurs when incident ionizing radiation deposits energy and excites electrons into the conduction band of insulators. Conductivity was measured when a voltage was applied across vacuum-baked, thin film polymer samples in a parallel plate geometry. RIC was calculated as the difference in sample conductivity under no incident radiation and under an incident ~4 MeV electron beam at low incident dose rates of 0.01 rad/sec to 10 rad/sec. The steady-state RIC was found to agree well with the standard power law relation, sigmaRIC(D˙) = kRIC(T) D˙Delta(T) between conductivity, sigmaRIC and adsorbed dose rate, D˙. Both the proportionality constant, kRIC, and the power, Delta, were found to be temperature-dependent above ~250 K, with behavior consistent with photoconductivity models developed for localized trap states in disordered semiconductors. Below ~250 K, kRIC and Delta exhibited little change in any of the materials.

Electro-induced protein deposition on low-fouling surfaces

NASA Astrophysics Data System (ADS)

Cole, M. A.; Voelcker, N. H.; Thissen, H.

2007-12-01

Control over protein adsorption is a key issue for numerous biomedical applications ranging from diagnostic microarrays to tissue-engineered medical devices. Here, we describe a method for creating surfaces that prevent non-specific protein adsorption, which upon application of an external trigger can be transformed into surfaces showing high protein adsorption on demand. Silicon wafers were used as substrate materials upon which thin functional coatings were constructed by the deposition of an allylamine plasma polymer followed by high-density grafting of poly(ethylene oxide) aldehyde, resulting in a low-fouling surface. When the underlying highly doped silicon substrate was used as an electrode, the resulting electrostatic attraction between the electrode and charged proteins in solution induced protein deposition at the low-fouling interface. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used to characterize the surface modifications. Controlled protein adsorption experiments were carried out using horseradish peroxidase. The amount of protein deposited at the surface was then investigated by means of a colorimetric assay. It is expected that the concept described here will find use in a variety of biotechnological and biomedical applications, particularly in the area of biochips.

Electron penetration of spacecraft thermal insulation

NASA Technical Reports Server (NTRS)

Powers, W. L.; Adams, B. F.; Inouye, G. T.

1981-01-01

The external thermal blanket with 13 mils of polyethylene which has the known range and stopping power as a function of electron energy is investiated. The most recent omnidirectional peak Jovian electron flux at 5 Jupiter radii is applied, the electron current penetrating the thermal blanket is calculated and allowed to impinge on a typical 20 mil polyethylene insulator surrounding a wire. The radiation dose rate to the insulator is then calculated and the electrical conductivity found. The results demonstrate that the increased electronic mobility is sufficient to keep the maximum induced electric field two orders of magnitude below the critical breakdown strength.

Optical data storage and metallization of polymers

NASA Technical Reports Server (NTRS)

Roland, C. M.; Sonnenschein, M. F.

1991-01-01

The utilization of polymers as media for optical data storage offers many potential benefits and consequently has been widely explored. New developments in thermal imaging are described, wherein high resolution lithography is accomplished without thermal smearing. The emphasis was on the use of poly(ethylene terephthalate) film, which simultaneously serves as both the substrate and the data storage medium. Both physical and chemical changes can be induced by the application of heat and, thereby, serve as a mechanism for high resolution optical data storage in polymers. The extension of the technique to obtain high resolution selective metallization of poly(ethylene terephthalate) is also described.

Introduction of starch into plastic films: Advent of starch in plastic

USDA-ARS?s Scientific Manuscript database

Following the oil crises of the 1970’s, scientists started thinking of alternative sources of materials that are not so dependent on foreign supplies. Probably riding on this concern, in part, came Griffin’s idea for creating a matted surface on low density polyethylene (LDPE) films in order to impr...

An alternate lining scheme for solar ponds - Results of a liner test rig

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raman, P.; Kishore, V.V.N.

1990-01-01

Solar pond lining schemes consisting of combinations of clays and Low Density Polyethylene (LDPE) films have been experimentally evaluated by means of a Solar Pond Liner Test Rig. Results indicate that LDPE film sandwiched between two layers of clay can be effectively used for lining solar ponds.

Application of laboratory fungal resistance tests to solid wood and wood-plastic composite

Treesearch

Craig Merrill Clemons; Rebecca E. Ibach

2003-01-01

The fungal resistance of high density polyethylene filled with 50% wood flour was investigated using laboratory soil block tests. Modifications to standard test methods were made to increase initial moisture content, increase exposure surface area, and track moisture content, mechanical properties, and weight loss over the exposure period. Mechanical properties...

Surface characterization of weathered wood-plastic composites produced from modified wood flour

Treesearch

James S. Fabiyi; Armando G. McDonald; Nicole M. Stark

2007-01-01

The effects of weathering on the surface properties of wood-plastic composites (WPC) were examined. High-density polyethylene (HDPE) based WPCs made from modified wood flour (untreated, extractives free, and holocellulose (delignified) fibers) were subjected to accelerated (xenon-arc) weathering. Colorimetry and Fourier-transform infrared spectroscopy were employed to...

77 FR 13387 - Pipeline Safety: Notice to Operators of Driscopipe® 8000 High Density Polyethylene Pipe of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-06

[email protected] . Pipeline operators with potentially affected pipe or anyone with questions specific to... affected pipe. Chemical contamination was considered a potential source for degradation, but after... investigation of this incident included checking for the possibility of nylon contamination in the pipe material...

Ultraviolet weathering of photostabilized wood-flour-filled high-density polyethylene composites

Treesearch

Nicole M. Stark; Laurent M. Matuana

2003-01-01

Wood–plastic composites are being increasingly examined for nonstructural or semistructural building applications. As outdoor applications become more widespread, durability becomes an issue. Ultraviolet exposure can lead to photodegradation, which results in a change in appearance and/or mechanical properties. Photodegradation can be slowed through the addition of...

Influence of nanoclay on properties of HDPE/wood composites

Treesearch

Yong Lei; Qinglin Wu; Craig M. Clemons; Fei Yao; Yanjun Xu

2007-01-01

Composites based on high density polyethylene (HDPE), pine flour, and organic clay were made by melt compounding and then injection molding. The influence of clay on crystallization behavior, mechanical properties, water absorption, and thermal stability of HDPE/pine composites was investigated. The HDPE/pine composites containing exfoliated clay were made by a two-...

Initial evaluation of floor cooling on lactating sows under severe acute heat stress

USDA-ARS?s Scientific Manuscript database

The objective was to evaluate the effects of floor cooling on lactating sows under severe summer heat stress. Twelve multiparous sows were provided with a cooling pad built with an aluminum plate surface, high-density polyethylene base and copper pipes. Treatments were randomly allotted to sows to r...

Effect of floor cooling on late lactation sows under acute heat stress

USDA-ARS?s Scientific Manuscript database

The objective was to evaluate the effects of floor cooling on late lactation sows under severe summer heat stress. Ten multiparous sows were provided with a cooling pad built with an aluminum plate surface, high-density polyethylene base and copper pipes. Treatments were randomly allotted to sows to...

Effects of floor cooling on late lactation sows under severe acute heat stress

USDA-ARS?s Scientific Manuscript database

The objective was to evaluate the effects of floor cooling on late lactation sows under severe summer heat stress. Ten multiparous sows were provided with a cooling pad built with an aluminum plate surface, high-density polyethylene base and copper pipes. Treatments were randomly allotted to sows to...

Initial evaluation of floor cooling on lactating sows under severe acute heat stress

USDA-ARS?s Scientific Manuscript database

The objectives were to evaluate an acute heat stress protocol for lactating sows and evaluate preliminary estimates of water flow rates required to cool sows. Twelve multiparous sows were provided with a cooling pad built with an aluminum plate surface, high-density polyethylene base and copper pipe...

Effect of organoclay on morphology and properties of linear low density polyethylene and Vietnamese cassava starch biobased blend.

PubMed

Nguyen, D M; Vu, T T; Grillet, Anne-Cécile; Ha Thuc, H; Ha Thuc, C N

2016-01-20

Linear low density polyethylene (LLDPE)/thermal plastic starch (TPS) blend was studied to prepare the biobased nanocomposite material using organoclay nanofil15 (N15) modified by alkilammonium as the reinforced phase. The LLDPE/TPS blend and its nanocomposites were elaborated by melt mixing method at 160 °C for 7 min. And the compounded sample was filmed by blowing method at three different zones of temperature profile which are 160-170-165 °C. The good dispersion of clay in the polymer blend matrix is showed by X-ray diffraction (XRD) and transmission electronic microscopy (TEM), and a semi-exfoliated structure was obtained. The thermal and mechanical properties of materials are enhanced when N15 is added to the mixture. The effect of N15 on morphology and particles size of TPS phase is also investigated. The biodegradation test shows that more than 60% in weight of LLDPE/TPS film is degraded into CO2, H2O, methane and biomass after 5 months in compost soil. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sorption Isotherm of Southern Yellow Pine-High Density Polyethylene Composites.

PubMed

Liu, Feihong; Han, Guangping; Cheng, Wanli; Wu, Qinglin

2015-01-20

Temperature and relative humidity (RH) are two major external factors, which affect equilibrium moisture content (EMC) of wood-plastic composites (WPCs). In this study, the effect of different durability treatments on sorption and desorption isotherms of southern yellow pine (SYP)-high density polyethylene (HDPE) composites was investigated. All samples were equilibriumed at 20 °C and various RHs including 16%, 33%, 45%, 66%, 75%, 85%, 93%, and100%. EMCs obtained from desorption and absorption for different WPC samples were compared with Nelson's sorption isotherm model predictions using the same temperature and humidity conditions. The results indicated that the amount of moisture absorbed increased with the increases in RH at 20 °C. All samples showed sorption hysteresis at a fixed RH. Small difference between EMC data of WPC samples containing different amount of ultraviolet (UV) stabilizers were observed. Similar results were observed among the samples containing different amount of zinc borate (ZB). The experimental data of EMCs at various RHs fit to the Nelson's sorption isotherm model well. The Nelson's model can be used to predicate EMCs of WPCs under different RH environmental conditions.

Melt fracture of linear low-density polyethylenes: Die geometry and molecular weight characteristics

NASA Astrophysics Data System (ADS)

Ebrahimi, Marzieh; Tomkovic, Tanja; Liu, Guochang; Doufas, Antonios A.; Hatzikiriakos, Savvas G.

2018-05-01

The melt fracture phenomena of three linear low-density polyethylenes are investigated as a function of die geometry (capillary, slit, and annular) and molecular weight and its distribution. The onset of melt fracture instabilities is determined by using capillary rheometry, mainly studying the extrudate appearance using optical microscopy. It is found that the onset of flow instabilities (melt fracture phenomena) is significantly affected by die geometry and molecular weight characteristics of the polymers. Use of annular die eliminates the stick-slip transition (oscillating melt fracture) and delays the onset of sharkskin to higher values of shear rate and shear stress. Moreover, it is shown that the molecular weight characteristics of the polymers are well correlated with critical conditions for the onset of flow instabilities based on a criterion proposed in the literature [A. Allal et al., "Relationships between molecular structure and sharkskin defect for linear polymers," J. Non-Newtonian Fluid Mech. 134, 127-135 (2006) and A. Allal and B. Vergnes, "Molecular design to eliminate sharkskin defect for linear polymers," J. Non-Newtonian Fluid Mech. 146, 45-50 (2007)].

In planta passive sampling devices for assessing subsurface chlorinated solvents.

PubMed

Shetty, Mikhil K; Limmer, Matt A; Waltermire, Kendra; Morrison, Glenn C; Burken, Joel G

2014-06-01

Contaminant concentrations in trees have been used to delineate groundwater contaminant plumes (i.e., phytoscreening); however, variability in tree composition hinders accurate measurement of contaminant concentrations in planta, particularly for long-term monitoring. This study investigated in planta passive sampling devices (PSDs), termed solid phase samplers (SPSs) to be used as a surrogate tree core. Characteristics studied for five materials included material-air partitioning coefficients (Kma) for chlorinated solvents, sampler equilibration time and field suitability. The materials investigated were polydimethylsiloxane (PDMS), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyoxymethylene (POM) and plasticized polyvinyl chloride (PVC). Both PDMS and LLDPE samplers demonstrated high partitioning coefficients and diffusivities and were further tested in greenhouse experiments and field trials. While most of the materials could be used for passive sampling, the PDMS SPSs performed best as an in planta sampler. Such a sampler was able to accurately measure trichloroethylene (TCE) and tetrachloroethylene (PCE) concentrations while simultaneously incorporating simple operation and minimal impact to the surrounding property and environment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Distinctive electrical properties in sandwich-structured Al2O3/low density polyethylene nanocomposites

NASA Astrophysics Data System (ADS)

Wang, Si-Jiao; Zha, Jun-Wei; Li, Wei-Kang; Dang, Zhi-Min

2016-02-01

The sandwich-structured Al2O3/low density polyethylene (Al2O3/LDPE) nanocomposite dielectrics consisting of layer-by-layer with different concentration Al2O3 loading were prepared by melt-blending and following hot pressing method. The space charge distribution from pulsed electro-acoustic method and breakdown strength of the nanocomposites were investigated. Compared with the single-layer Al2O3/LDPE nanocomposites, the sandwich-structured nanocomposites remarkably suppressed the space charge accumulation and presented higher breakdown strength. The charges in the sandwich-structured nanocomposites decayed much faster than that in the single-layer nanocomposites, which was attributed to an effective electric field caused by the formation of the interfacial space charges. The energy depth of shallow and deep traps was estimated as 0.73 eV and 1.17 eV in the sandwich-structured nanocomposites, respectively, according to the thermal excitation theoretical model we proposed. This work provides an attractive strategy of design and fabrication of polymer nanocomposites with excellent space charge suppression.

Pyrolysis of low density polyethylene waste in subcritical water optimized by response surface methodology.

PubMed

Wong, S L; Ngadi, N; Amin, N A S; Abdullah, T A T; Inuwa, I M

2016-01-01

Pyrolysis of low density polyethylene (LDPE) waste from local waste separation company in subcritical water was conducted to investigate the effect of reaction time, temperature, as well as the mass ratio of water to polymer on the liquid yield. The data obtained from the study were used to optimize the liquid yield using response surface methodology. The range of reaction temperature used was 162-338°C, while the reaction time ranged from 37 min to 143 min, and the ratio of water to polymer ranged from 1.9 to 7.1. It was found that pyrolysis of LDPE waste in subcritical water produced hydrogen, methane, carbon monoxide and carbon dioxide, while the liquid product contained alkanes and alkenes with 10-50 carbons atoms, as well as heptadecanone, dichloroacetic acid and heptadecyl ester. The optimized conditions were 152.3°C, reaction time of 1.2 min and ratio of water solution to polymer of 32.7, with the optimum liquid yield of 13.6 wt% and gases yield of 2.6 wt%.

The effect of EGDMA on tensile and thermal properties of irradiated low density polyethylene/sepiolite nanocomposites

NASA Astrophysics Data System (ADS)

Ghazali, Siti Nadia Aini; Mohamad, Zurina; Majid, Rohah A.; Appadu, Sivanesan

2017-07-01

This study presents the influence of ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent through electron beam crosslinking process. Therefore, the effects of EGDMA on irradiated low density polyethylene/sepiolite (LDPE/SEP) nanocomposites on the tensile and thermal properties at 4 part per hundred resin (phr) sepiolite were investigated. The LDPE/SEP nanocomposites were prepared by melt mixing using twin screw extruder at 160 ˚C with a screw speed of 50 rpm. The nanocomposites were then undergone injection moulding process followed by irradiated using 2 MeV electron beam machine at doses ranging from 0 to 200 kGy in the air at ambient temperature. It was found that the tensile strength and Young's modulus were slightly increased with the presence of co-agent. The sample containing 4 phr sepiolite at 200 kGy showed 9% increase in tensile strength when EGDMA was added. However, the result of thermogravimetry analysis (TGA) showed some reduction in thermal stability of nanocomposites on 100 kGy irradiation dose. EGDMA had reduced the optimum irradiation dose without having any adverse effect on tensile and thermal properties.

Properties of concrete modified with waste Low Density Polyethylene and saw dust ash

NASA Astrophysics Data System (ADS)

Srimanikandan, P.; Sreenath, S.

2017-07-01

The increase in industrialization creates need for disposal of large quantity of by-products. To overcome the difficulty of disposal, these by-products can be used as a replacement for raw material. In this concern, non-conventional industrial wastes such as plastic bags, PET bottles, pulverized waste Low Density Polyethylene (LDPE) and biological waste such as saw-dust ash, coconut coir were used as a replacement in concrete. In this project, saw-dust ash and pulverized waste LDPE were introduced as the partial replacement for cement and fine aggregates respectively. 0%, 5%, 10%, 15% and 20% of sand by volume was replaced with LDPE and 0%, 1%, 3%, 5% and 10% of cement by volume was replaced with saw dust ash. Standard cube, cylinder and prism specimens were cast to assess the compressive strength, split tensile strength and flexural strength of modified concrete after 28 days of curing. Optimum percentage of replacement was found by comparing the test results. The mix with 5% of LDPE and 3% of saw dust ash showed a better result among the other mixes.

Evaluation of the effect of reprocessing on the structure and properties of low density polyethylene/thermoplastic starch blends.

PubMed

Peres, Anderson M; Pires, Ruthe R; Oréfice, Rodrigo L

2016-01-20

The great quantity of synthetic plastic discarded inappropriately in the environment is forcing the search for materials that can be reprocessable and biodegradable. Blends between synthetic polymers and natural and biodegradable polymers can be good candidates of such novel materials because they can combine processability with biodegradation and the use of renewable raw materials. However, traditional polymers usually present high levels of recyclability and use the well-established recycling infrastructure that can eventually be affected by the introduction of systems containing natural polymers. Thus, this work aims to evaluate the effect of reprocessing (simulated here by multiple extrusions) on the structure and properties of a low density polyethylene/thermoplastic starch (LDPE/TPS) blend compared to LDPE. The results indicated that multiple extrusion steps led to a reduction in the average size of the starch-rich phases of LDPE/TPS blends and minor changes in the mechanical and rheological properties of the materials. Such results suggest that the LDPE/TPS blend presents similar reprocessability to the LDPE for the experimental conditions used. Copyright © 2015 Elsevier Ltd. All rights reserved.

Decay of low-density polyethylene by bacteria extracted from earthworm's guts: A potential for soil restoration.

PubMed

Huerta Lwanga, Esperanza; Thapa, Binita; Yang, Xiaomei; Gertsen, Henny; Salánki, Tamás; Geissen, Violette; Garbeva, Paolina

2018-05-15

Low-density polyethylene (LDPE) is the most abundant source of microplastic pollution worldwide. A recent study found that LDPE decay was increased and the size of the plastic was decreased after passing through the gut of the earthworm Lumbricus terrestris (Oligochaeta). Here, we investigated the involvement of earthworm gut bacteria in the microplastic decay. The bacteria isolated from the earthworm's gut were Gram-positive, belonging to phylum Actinobacteria and Firmicutes. These bacteria were used in a short-term microcosm experiment performed with gamma-sterilized soil with or without LDPE microplastics (MP). We observed that the LDPE-MP particle size was significantly reduced in the presence of bacteria. In addition, the volatile profiles of the treatments were compared and clear differences were detected. Several volatile compounds such as octadecane, eicosane, docosane and tricosane were measured only in the treatments containing both bacteria and LDPE-MP, indicating that these long-chain alkanes are byproducts of bacterial LDPE-MP decay. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Influence of triallyl cyanurate as co-agent on gamma irradiation cured high density polyethylene/reclaimed tire rubber blend

NASA Astrophysics Data System (ADS)

Mali, Manoj N.; Arakh, Amar A.; Dubey, K. A.; Mhaske, S. T.

2017-02-01

Utilization of waste from tire industry as reclaimed tire rubber (RTR) by formation of blends with high density polyethylene (HDPE) is great area to be focused. Enhancement of properties by the addition of triallyl cyanurate (TAC) as a co-agent with 1%, 3% and 5% to blend of HDPE 50 wt% and RTR 50 wt% in presence of gamma irradiation curing were investigated. Specifically, mechanical and thermal properties were studied as a function of amount of TAC and gamma irradiation dose in range of 50-200 kGy. The resultant blends were evaluated for the values of impact strength, gel content, thermal stability, tensile properties, rheological properties and morphological properties with increasing irradiation dosage and TAC loading. The mechanical properties tensile strength, hardness, impact strength of blend containing 3% of TAC were substantially increased with increasing irradiation dosage up to 150 KGy. Rheological analysis has shown increase in viscosity with increase in TAC loading up to 3% and 150 KGy irradiation dosages. 3% loading of TAC lead to better set of properties with150 KGy gamma irradiation dosage.

Diffusion of multiwall carbon nanotubes (MWCNTs) through a high density polyethylene (HDPE) geomembrane.

PubMed

Saheli, P T; Rowe, R K; Petersen, E J; O'Carroll, D M

2017-05-01

The new applications for carbon nanotubes (CNTs) in various fields and consequently their greater production volume have increased their potential release to the environment. Landfills are one of the major locations where carbon nanotubes are expected to be disposed and it is important to ensure that they can limit the release of CNTs. Diffusion of multiwall carbon nanotubes (MWCNTs) dispersed in an aqueous media through a high-density polyethylene (HDPE) geomembrane (as a part of the landfill barrier system) was examined. Based on the laboratory tests, the permeation coefficient was estimated to be less than 5.1×10 -15 m 2 /s. The potential performance of a HDPE geomembrane and geosynthetic clay liner (GCL) as parts of a composite liner in containing MWCNTs was modelled for six different scenarios. The results suggest that the low value of permeation coefficient of an HDPE geomembrane makes it an effective diffusive barrier for MWCNTs and by keeping the geomembrane defects to minimum during the construction (e.g., number of holes and length of wrinkles) a composite liner commonly used in municipal solid waste landfills will effectively contain MWCNTs.

Radiolysis products and sensory properties of electron-beam-irradiated high-barrier food-packaging films containing a buried layer of recycled low-density polyethylene.

PubMed

Chytiri, S D; Badeka, A V; Riganakos, K A; Kontominas, M G

2010-04-01

The aim was to study the effect of electron-beam irradiation on the production of radiolysis products and sensory changes in experimental high-barrier packaging films composed of polyamide (PA), ethylene-vinyl alcohol (EVOH) and low-density polyethylene (LDPE). Films contained a middle buried layer of recycled LDPE, while films containing 100% virgin LDPE as the middle buried layer were taken as controls. Irradiation doses ranged between zero and 60 kGy. Generally, a large number of radiolysis products were produced during electron-beam irradiation, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food 'cold pasteurization'). The quantity of radiolysis products increased with irradiation dose. There were no significant differences in radiolysis products identified between samples containing a recycled layer of LDPE and those containing virgin LDPE (all absorbed doses), indicating the 'functional barrier' properties of external virgin polymer layers. Sensory properties (mainly taste) of potable water were affected after contact with irradiated as low as 5 kGy packaging films. This effect increased with increasing irradiation dose.

Fast co-pyrolysis of waste newspaper with high-density polyethylene for high yields of alcohols and hydrocarbons.

PubMed

Chen, Weimin; Shi, Shukai; Chen, Minzhi; Zhou, Xiaoyan

2017-09-01

Waste newspaper (WP) was first co-pyrolyzed with high-density polyethylene (HDPE) using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to enhance the yields of alcohols and hydrocarbons. The effects of WP: HDPE feed ratio (100:0, 75:25, 50:50, 25:75, 0:100) and temperature (500-800°C) on products distribution were investigated and the interaction mechanism during co-pyrolysis was also proposed. Maximum yields of alcohols and hydrocarbons reached 85.88% (feed ratio 50:50wt.%, 600°C). Hydrogen supplements and deoxidation by HDPE and subsequently fragments recombination result in the conversion of aldehydes and ketones into branched hydrocarbons. Radicals from WP degradation favor the secondary crack for HDPE products resulting in the formation of linear hydrocarbons with low carbon number. Hydrocarbons with activated radical site from HDPE degradation were interacted with hydroxyl from WP degradation promoting the formation of linear long chain alcohols. Moreover, co-pyrolysis significantly enhanced condensable oil qualities, which were close to commercial diesel No. 0. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simulated glass transition of poly(ethylene oxide) bulk and film: a comparative study.

PubMed

Wu, Chaofu

2011-09-29

Stepwise cooling molecular dynamics (MD) simulations have been carried out on the bulk and film models for poly(ethylene oxide) (PEO) to understand glass transition of amorphous polymer films. Three types of properties--density, energy, and dynamics--are computed and plotted against the temperature for the two systems. It has been confirmed that all these properties can reveal glass transition in both PEO bulk and film systems. All the determined glass transition temperatures (T(g)'s) drop in the same order of magnitude to the experimental data available. Among various methods, the T(g)'s obtained from the density and energy data are close to each other if the same space regions are defined, which can suggest the same free volume theory, and dynamic T(g)'s obtained from mean-squared displacements (MSDs) are highest, which can suggest the kinetic theory for structural relaxation. Consistently, all these T(g)'s obtained using different methods show that the T(g)'s of PEO film are lower than those of PEO bulk. The free surface layers of polymer films dictate this offset. © 2011 American Chemical Society

Sorption Isotherm of Southern Yellow Pine—High Density Polyethylene Composites

PubMed Central

Liu, Feihong; Han, Guangping; Cheng, Wanli; Wu, Qinglin

2015-01-01

Temperature and relative humidity (RH) are two major external factors, which affect equilibrium moisture content (EMC) of wood-plastic composites (WPCs). In this study, the effect of different durability treatments on sorption and desorption isotherms of southern yellow pine (SYP)-high density polyethylene (HDPE) composites was investigated. All samples were equilibriumed at 20 °C and various RHs including 16%, 33%, 45%, 66%, 75%, 85%, 93%, and100%. EMCs obtained from desorption and absorption for different WPC samples were compared with Nelson’s sorption isotherm model predictions using the same temperature and humidity conditions. The results indicated that the amount of moisture absorbed increased with the increases in RH at 20 °C. All samples showed sorption hysteresis at a fixed RH. Small difference between EMC data of WPC samples containing different amount of ultraviolet (UV) stabilizers were observed. Similar results were observed among the samples containing different amount of zinc borate (ZB). The experimental data of EMCs at various RHs fit to the Nelson’s sorption isotherm model well. The Nelson’s model can be used to predicate EMCs of WPCs under different RH environmental conditions. PMID:28787943

Abiotic degradation of plastic films

NASA Astrophysics Data System (ADS)

Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

2017-01-01

Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

Polyethylene Glycol-Functionalized Magnetic Fe₃O₄/P(MMA-AA) Composite Nanoparticles Enhancing Efficient Capture of Circulating Tumor Cells.

PubMed

Ma, Shaohua; Zhan, Xiaohui; Yang, Minggang; Lan, Fang; Wu, Yao; Gu, Zhongwei

2018-04-01

Circulating tumor cells (CTCs) played a significant role in early diagnosis and prognosis of carcinomas, and efficient capture of CTCs was highly desired to provide important and reliable evidence for clinical diagnosis. In present work, we successfully synthesized functional magnetic Fe3O4/P(MMA-AA) composite nanoparticles (FCNPs) inspired by a counterbalance concept for recognition and capture of CTCs. This counterbalance, composed of polyethylene glycol (PEG) suppressing cell adhesion and anti-epithelial-cell-adhesion-molecule (anti-EpCAM) antibody targeting tumor cells, could both enhance the specific capture of tumor cells and reduce unspecific adhesion of normal cells. The study showed that the PEG density on the surface of the FCNPs affected the specificity of the materials, and a density of ca. 15% was efficient for reducing the unspecific adhesion. After incubation with the mixture of HepG2 cells and Jurkat T cells, the FCNPs reached a capture efficiency as high as about 86.5% of the cancer cells, suggesting great potential on detection of CTCs in the diagnoses and prognoses of cancer metastasis.

Biomarker responses in zebrafish (Danio rerio) larvae exposed to pristine low-density polyethylene fragments.

PubMed

Karami, Ali; Groman, David B; Wilson, Scott P; Ismail, Patimah; Neela, Vasantha K

2017-04-01

There are serious concerns over the adverse impacts of microplastics (MPs) on living organisms. The main objective of this study was to test the effects of MPs on the total length, weight, condition factor (CF), transcriptional level of antioxidant, anti and pro-apoptotic, and neurotransmitter genes, and the histopathology of the gill, liver, brain, kidney, and intestine in the larvae of zebrafish (Danio rerio). Fish were exposed to one of three levels of pristine low-density polyethylene (LDPE) fragments (5, 50, or 500 μg/L) for 10 or 20 days. No significant changes were observed in any of the selected biomarkers across MP concentrations at days 10 or 20. The expression of casp9 (caspase 9, apoptosis-related cysteine protease), casp3a (caspase 3, apoptosis-related cysteine protease a) and cat (catalase), however, were significantly lower in the larvae sampled at day 20 than day 10. We provide evidence that virgin short-term exposure to LDPE fragments has minimal impact on biomarker responses in D. rerio larvae. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of wood flour content on the optical color, surface chemistry, mechanical and morphological properties of wood flour/recycled high density polyethylene (rHDPE) composite

NASA Astrophysics Data System (ADS)

Sheng, Chan Kok; Amin, Khairul Anuar Mat; Kee, Kwa Bee; Hassan, Mohd Faiz; Ali, E. Ghapur E.

2018-05-01

In this study, effect of wood flour content on the color, surface chemistry, mechanical properties and surface morphology of wood-plastic composite (WPC) on different mixture ratios of recycled high density polyethylene (rHDPE) and wood flour were investigated in detail. The presence of wood flour in the composite indicates a significant total color change and a decrease of lightness. Functional groups of wood flour in WPC can be seen clearer from the Fourier transform infrared (FTIR) spectra as the wood flour content increases. The mechanical tensile testing shows that the tensile strength of Young's modulus is improved, whereas the strain and elongation at break were reduced by the addition of wood flour. The gap between the wood flour microvoid fibre and rHDPE matrix becomes closer when the wood flour content is increased as observed by scanning electron microscope (SEM) image. This finding implies a significant improvement on the interaction of interfacial adhesion between the rHDPE matrix and wood flour filler in the present WPC.

Characterization of laser beam transmission through a High Density Polyethylene (HDPE) plate

NASA Astrophysics Data System (ADS)

Genna, S.; Leone, C.; Tagliaferri, V.

2017-02-01

Infrared (IR) light propagation in semicrystalline polymers involves mechanisms such as reflection, transmission, absorption and internal scattering. These different rates determine either the interaction mechanism, either the temperatures reached in the IR heating processes. Consequently, the knowledge of these rates is fundamental in the development of IR heating processes in order to avoid the polymer's damage and to increase the process energy efficiency. Aim of this work is to assess a simple procedure to determine the rates of absorbed, reflected, transmitted and scattered energy in the case of an unfilled High Density Polyethylene (HDPE) plate. Experimental tests were performed by exposing a HDPE plate, 3 mm in thickness, to a diode laser source, working at the fundamental wavelength of 975 nm. The transmitted power was measured by power meter, the reflected one by applying the Beer-Lambert law to sample of different thickness. IR thermal images were adopted to measure the absorbed ratio. The scattered ratio was measured by energetic balance, as difference between the incoming power and the other ratios. Finally, IR thermal images were adopted to measure the scattered ratio and to validate the procedure.

Ultrasonic attenuation and phase velocity of high-density polyethylene pipe material.

PubMed

Egerton, J S; Lowe, M J S; Huthwaite, P; Halai, H V

2017-03-01

Knowledge of acoustic properties is crucial for ultrasonic or sonic imaging and signal detection in nondestructive evaluation (NDE), medical imaging, and seismology. Accurately and reliably obtaining these is particularly challenging for the NDE of high-density polyethylene (HDPE), such as is used in many water or gas pipes, because the properties vary greatly with frequency, temperature, direction and spatial location. Therefore the work reported here was undertaken in order to establish a basis for such a multiparameter description. The approach is general but the study specifically addresses HDPE and includes measured data values. Applicable to any such multiparameter acoustic properties dataset is a devised regression method that uses a neural network algorithm. This algorithm includes constraints to respect the Kramers-Kronig causality relationship between speed and attenuation of waves in a viscoelastic medium. These constrained acoustic properties are fully described in a multidimensional parameter space to vary with frequency, depth, temperature, and direction. The resulting uncertainties in acoustic properties dependence on the above variables are better than 4% and 2%, respectively, for attenuation and phase velocity and therefore can prevent major defect imaging errors.

Radiation-assisted grafting of vinylidene chloride onto high-density polyethylene

NASA Astrophysics Data System (ADS)

Nagesh, N.; Dokhale, P. A.; Bhoraskar, V. N.

1999-06-01

6 MeV electrons and Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays were used for grafting vinylidene chloride (VDC) onto high-density polyethylene (HDPE) samples. The HDPE samples were immersed in vinylidene chloride and irradiated either with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays or with 6 MeV electrons. In both cases, the radiation dose was varied in the range 1.25-7.5 kGy. The grafted samples were characterized by IR spectroscopy to obtain information about the chemical bonds and with the 14 MeV neutron activation analysis technique for estimating the number of chlorine atoms. The formation of stable bonds between the VDC molecules and the polymer chains could be achieved either with 6 MeV electrons or with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays. Both the number of chlorine atoms and the sample-surface conductivity increased with the radiation dose but the increases achieved with 6 MeV electrons were greater than those achieved with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays.

Polymer Grafted Nanoparticles for Designed Interfaces in Polymer Nanocomposites

NASA Astrophysics Data System (ADS)

Mohammadkhani, Mohammad

This dissertation presents the design, synthesis, and characterization of polymer nanocomposite interfaces and the property enhancement from this interface design. Through the use of reversible addition fragmentation chain transfer (RAFT) polymerization for the grafting of polymer chains to silica nanoparticles, the surface of silica nanoparticles can be manipulated to tune the properties of nanocomposites by controlling the interface between the particles and the polymer matrix. In the first part of this work, compatibility of 15 nm silica nanoparticles grafted with different alkyl methacrylates with linear low density polyethylene was investigated. SI-RAFT polymerization of hexyl, lauryl, and stearyl methacrylate on silica NPs was studied in detail and revealed living character for all these polymerizations. Composites of linear low density polyethylene filled with PHMA, PLMA, and PSMA-g-SiO2 NPs were prepared and analyzed to find the effects of side chain length on the dispersibility of particles throughout the matrix. PSMA brushes were the most "olefin-like" of the series and thus showed the highest compatibility with polyethylene. The effects of PSMA brush molecular weight and chain density on the dispersion of silica particles were investigated. Multiple characterizations such as DSC, WAXS, and SAXS were applied to study the interaction between PSMA-g-SiO2 NPs and the polyethylene matrix. In the next part, the compatibility of PSMA-g-SiO2 NPs with different molecular variables with isotactic polypropylene was investigated. Anthracene was used as a conjugated ligand to introduce to the surface of PSMA-g-SiO2 NPs to develop bimodal architecture on nanoparticles and use them in polypropylene dielectric nanocomposites. The dispersion of particles was investigated and showed that for both monomodal and bimodal particles where PSMA chains are medium density and relatively high molecular weight, they maintain an acceptable level of dispersion throughout of the matrix. Furthermore, the effects of anthracene surface modification and also level of dispersion towards improving the dielectric breakdown strength under AC and DC conditions were studied. Finally, the RAFT polymerizations of isoprene in solution and, for the first time, on the surface of silica particles using a high temperature stable trithiocarbonate RAFT agent were studied. The effects of different temperatures, initiators, and monomer feed ratios on the kinetics of the SI-RAFT polymerization were also investigated. Kinetic studies revealed that the rate of SI-RAFT polymerization increased with an increase in the density of grafted RAFT agent. Well-defined polyisoprene-grafted silica NPs (PIP-g-SiO2 NPs) were synthesized and mixed with a polyisoprene matrix to determine the compatibility and dispersion of these particles with the matrix. Hydrogenation of PIP-g-SiO2 NPs were performed using p-toluenesulfonyl hydrazide at high temperature to obtain hydrogenated (HPIP)-g-SiO2 NPs. A bimodal octadecylsilane (C18)-HPIP-g-SiO2 NPs sample was synthesized and mixed with isotactic PP matrix analyzed for the compatibility with polypropylene.

A simple method for the extraction and identification of light density microplastics from soil.

PubMed

Zhang, Shaoliang; Yang, Xiaomei; Gertsen, Hennie; Peters, Piet; Salánki, Tamás; Geissen, Violette

2018-03-01

This article introduces a simple and cost-saving method developed to extract, distinguish and quantify light density microplastics of polyethylene (PE) and polypropylene (PP) in soil. A floatation method using distilled water was used to extract the light density microplastics from soil samples. Microplastics and impurities were identified using a heating method (3-5s at 130°C). The number and size of particles were determined using a camera (Leica DFC 425) connected to a microscope (Leica wild M3C, Type S, simple light, 6.4×). Quantification of the microplastics was conducted using a developed model. Results showed that the floatation method was effective in extracting microplastics from soils, with recovery rates of approximately 90%. After being exposed to heat, the microplastics in the soil samples melted and were transformed into circular transparent particles while other impurities, such as organic matter and silicates were not changed by the heat. Regression analysis of microplastics weight and particle volume (a calculation based on image J software analysis) after heating showed the best fit (y=1.14x+0.46, R 2 =99%, p<0.001). Recovery rates based on the empirical model method were >80%. Results from field samples collected from North-western China prove that our method of repetitive floatation and heating can be used to extract, distinguish and quantify light density polyethylene microplastics in soils. Microplastics mass can be evaluated using the empirical model. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of the Mechanical Properties of Electrorheological Fluids Made of Starch and Silicone Fluid

NASA Astrophysics Data System (ADS)

Vieira, Sheila Lopes; de Arruda, Antonio Celso Fonseca

In the majority of published articles on the topic, ER fluids have been studied as if they were viscous liquids. In this work, electrorheological fluids were characterized as solids and their mechanical properties were determined. The results infer that ER materials are controllably resistant to compression, tensile and shear stress, in this order of magnitude. More precisely, fluids made of starch have elasticity modulus similar to that of rubber, they have tensile strength 103 to 5×104 times lower than that of low density polyethylene (LDPE), static yield stress 4×104 to 8×105 times lower than that of acrylonitrile-butadiene-styrene terpolymer (ABS) and fatigue life similar to some polymers like polyethylene(PE) and polypropylene (PP).

Effect of processing method on the mechanical and thermal of Silvergrass/HDPE composites

NASA Astrophysics Data System (ADS)

Liu, Bing; Jin, Yueqiang; Wang, Shuying

2017-05-01

This paper investigates the effect of compression and injection molding methods on properties of Silvergrass-HDPE (High Density Polyethylene) composites, with respect to mechanical behaviors. Maleated polyethylene (MAPE) was added in the composite and improved the mechanical property of the composite. The research founds MAPE can improve the mechanical property because it improved the interfacial compatibility as a coupling agent. When added a content of 8% of MAPE, Silvergrass-HDPE composites made from compression molding shows a better mechanical performance in tensile strength and flexural strength than that made from injection molding, with increasing Silvergrass fiber content from 30% to 50%. However, the WPCs (wood plastics composites) made from injection molding had a lower degree of crystallinity with or without MAPE treatment.

Development of multi-layer plastic fuel tanks for Nissan research vehicle-II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurihara, Y.; Nakazawa, K.; Ohashi, K.

1987-01-01

Plastic fuel tanks are light in weight and rustproof, and have good design flexibility. For those currently in use, however, which are made of mono-layer high-density polyethylene, fuel permeability is too high to meet U.S. evaporative emission standards, which are stricter than those in Japan or the EEC. For minimize fuel permeation, the formation of a barrier layer of polyamide resin by multi-layer (three-resin five-layer) blow molding is considered more promising than sulphonation or fluorination treatment of the polyethylene resin. This paper describes the fuel permeation mechanism, then outlines the development of a multi-layer plastic fuel tank, and discusses itsmore » structural features and the development of resins.« less

Effect of compatibilizer on impact and morphological analysis of recycled HDPE/PET blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salleh, Mohd Nazry; Ahmad, Sahrim; Ghani, Mohd Hafizuddin Ab

Blends based on recycled high density polyethylene (rHDPE) and recycled polyethylene terephthalate (rPET) were prepared using a corotating twin screw extruder. PET and HDPE are incompatible polymers and their blends showed poor properties. Compatibilization is a step to obtain blends with good mechanical properties and in this work, ethylene glycidyl methacrylate copolymer (E-GMA) was used as a compatibilizing agent. The effect of blends based on rHDPE and rPET with and without a compatibilizer, E-GMA were examined. From the studies clearly showed that the addition of 5% E-GMA increased the impact strength. SEM analysis of rHDPE/rPET blends confirmed the morphological interactionmore » and improved interfacial bonding between two phases.« less

Controlled Emissivity Coatings to Delay Ignition of Polyethylene.

PubMed

Sonnier, Rodolphe; Ferry, Laurent; Gallard, Benjamin; Boudenne, Abderrahim; Lavaud, François

2015-10-12

Semi-opaque to opaque films containing small amounts of various aluminium particles to decrease emissivity were easily prepared and coated onto low-density polyethylene (LDPE) sheets. The thermal-radiative properties (reflectivity, transmissivity and absorptivity) of the films were measured and related to the aluminum particles' content, size and nature. Time-to-ignition of samples was assessed using a cone calorimeter at different heat flux values (35, 50 and 75 kW/m²). The coatings allowed significant ignition delay and, in some cases, changed the material behaviour from thermally thin to thick behaviour. These effects are related both to their emissivity and transmissivity. A lower emissivity, which decreases during the degradation, and a lower transmissivity are the key points to ensure an optimal reaction-to-fire.

Does the liquid method of electret forming influence the adhesion of blood platelets?

PubMed

Lowkis, B; Szymanowicz, M

1995-01-01

This work presents the results of the effect of the electric charge on the adhesion of blood platelets. All experiments were carried out on polyethylene foil. The liquid method was used to form electrets. The evaluation of the electret effect influence on the adhesion of blood platelets was made on the basis of the observation of the electret surface after the contact with fresh citrate human blood group O Rh+ in an electron scanning microscope. Experimental results confirmed the essential influence of the electric charge on the process of adhesion of blood platelets. It was noticed that the preliminary aging of electrets decreases the density of the surface charge and improves the athrombogenic characteristics of polyethylene foil.

Adsorption of poly(ethylene oxide) on smectite: Effect of layer charge.

PubMed

Su, Chia-Chi; Shen, Yun-Hwei

2009-04-01

The adsorption of polymers on clay is important in many applications. However the mechanisms of poly(ethylene oxide) (PEO) adsorption on smectite is not well elucidated at present. The aim of this study was to investigate the effect of layer charge density on the adsorption of PEO by smectite. The results indicated that both the hydrophobic interaction (between CH(2)CH(2) groups and siloxane surface) and the hydrogen bonding (between ether oxygen of PEO and structure OH of smectite) lead to PEO preferential adsorption on the surface of low-charge smectite. In addition, the delamination of low-charge smectite in water is enhanced upon PEO adsorption presumably due to the hydrophilic ether oxygen of adsorbed PEO.

High density, uniformly distributed W/UO2 for use in Nuclear Thermal Propulsion

NASA Astrophysics Data System (ADS)

Tucker, Dennis S.; Barnes, Marvin W.; Hone, Lance; Cook, Steven

2017-04-01

An inexpensive, quick method has been developed to obtain uniform distributions of UO2 particles in a tungsten matrix utilizing 0.5 wt percent low density polyethylene. Powders were sintered in a Spark Plasma Sintering (SPS) furnace at 1600 °C, 1700 °C, 1750 °C, 1800 °C and 1850 °C using a modified sintering profile. This resulted in a uniform distribution of UO2 particles in a tungsten matrix with high densities, reaching 99.46% of theoretical for the sample sintered at 1850 °C. The powder process is described and the results of this study are given below.

Interferometer density measurements of a high-velocity plasmoid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Case, A.; Messer, S.; Bomgardner, R.

2010-05-15

The plasmoid produced by a half-scale contoured gap coaxial plasma accelerator using ablative polyethylene capillary plasma injectors is measured using a quadrature heterodyne HeNe interferometer. The plasmoid is found to have a sharp rise in density at the leading edge, with a gradual falloff after the peak density. For this early test series, an average bulk density of 5x10{sup 14} cm{sup -3} is observed, with densities up to 8x10{sup 14} cm{sup -3} seen on some shots. Although plasmoid mass is only about 58 mug due to the low current and injected mass used in these tests, good shot-to-shot repeatability ismore » attained making analysis relatively straightforward, thus providing a solid foundation for interpreting future experimental results.« less

Space charge characteristics of fluorinated polyethylene: Different effects of fluorine and oxygen

NASA Astrophysics Data System (ADS)

Zhao, Ni; Nie, Yongjie; Li, Shengtao

2018-04-01

Direct fluorination are proved having obvious effect on space charge characteristics of polyethylene. It is believed that fluorine has a positive effect on suppressing space charge injection while oxygen impurity has a negative effect. However, the mechanism for the opposite effect of fluorine and oxygen is still not clear. In this paper, the different effects of fluorine and oxygen on space charge characteristics of fluorinated low density polyethylene (LDPE) are investigated on the basis of dielectric property, chemical constitutes and trap performance of surface fluorinated layers. The results show that direct fluorination has obvious effect on chemical constitutes and dielectric properties of surface fluorinated layer. Introduced fluorine is the main factor for suppressing charge injection from the electrodes, because it seriously changes the chemical constitutes and further the trap properties of the surface fluorinated layer. While introduction of oxygen results in heterocharges and makes space charge distribution complex, due to the ionization of generated small groups like C=O containing groups. Moreover, direct fluorination will result in cleavage of some LDPE molecules whatever there is oxygen impurity or not.

Ni-H2 cell separator matrix engineering

NASA Technical Reports Server (NTRS)

Scott, W. E.

1992-01-01

This project was initiated to develop alternative separator materials to the previously used asbestos matrices which were removed from the market for health and environmental reasons. The objective of the research was to find a material or combination of materials that had the following characteristics: (1) resistant to the severe conditions encountered in Ni-H2 cells; (2) satisfactory electrical, electrolyte management, and thermal management properties to function properly; (3) environmentally benign; and (4) capable of being manufactured into a separator matrix. During the course of the research it was discovered that separators prepared from wettable polyethylene fibers along and in combination with potassium titanate pigment performed satisfactory in preliminary characterization tests. Further studies lead to the optimization of the separator composition and manufacturing process. Single ply separator sheets were manufactured with 100 percent polyethylene fibers and also with a combination of polyethylene fibers and potassium titanate pigment (PKT) in the ratio of 60 percent PKT and 40 percent fibers. A pilot paper machine was used to produce the experimental separator material by a continuous, wet laid process. Both types of matrices were produced at several different area densities (grams/sq m).

Enhanced flashover strength in polyethylene nanodielectrics by secondary electron emission modification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Weiwang; Li, Shengtao, E-mail: sli@xjtu.edu.cn; Min, Daomin

2016-04-15

This work studies the correlation between secondary electron emission (SEE) characteristics and impulse surface flashover in polyethylene nanodielectrics both theoretically and experimentally, and illustrates the enhancement of flashover voltage in low-density polyethylene (LDPE) through incorporating Al{sub 2}O{sub 3} nanoparticles. SEE characteristics play key roles in surface charging and gas desorption during surface flashover. This work demonstrates that the presence of Al{sub 2}O{sub 3} nanoparticles decreases the SEE coefficient of LDPE and enhances the impact energy at the equilibrium state of surface charging. These changes can be explained by the increase of surface roughness and of surface ionization energy, and themore » strong interaction between nanoparticles and the polymer dielectric matrix. The surface charge and flashover voltage are calculated according to the secondary electron emission avalanche (SEEA) model, which reveals that the positive surface charges are reduced near the cathode triple point, while the presence of more nanoparticles in high loading samples enhances the gas desorption. Consequently, the surface flashover performance of LDPE/Al{sub 2}O{sub 3} nanodielectrics is improved.« less

Surface modification of polyethylene/graphene composite using corona discharge

NASA Astrophysics Data System (ADS)

Popelka, Anton; Noorunnisa Khanam, P.; AlMaadeed, Mariam Ali

2018-03-01

Polyethylene/graphene composites are suitable for electromagnetic interference shielding applications and are often fabricated as sandwich structures. However, the hydrophobic character of these composites can lead to delamination. Corona treatment was used to enhance the surface hydrophilicity of composites prepared from linear low-density polyethylene (LLDPE) and graphene nanoplatelets (GNPs) with different content (2, 4, 6, and 8 wt.%). This enhancement of wettability also led to good adhesion properties. The presence of GNPs in LLDPE had a positive effect on the surface properties after corona treatment. The surface free energy of the LLDPE/GNP composites increased by almost 64.6% for 2 wt.% of GNPs in the LLDPE/GNP composite, while the surface free energy of neat LLDPE increased by only 38.1%. The best improvement in adhesion properties after corona treatment was observed for 2 wt.% of GNPs in the LLDPE/GNP composite, while peel resistance increased by 137.9%. Various analytical techniques and methods proved that the changes in the surface morphology and chemical composition of the LLDPE/GNP composite after this treatment resulted in an improvement of adhesion.

Relationship between Salt Tolerance and Resistance to Polyethylene Glycol-Induced Water Stress in Cultured Citrus Cells 1

PubMed Central

Ben-Hayyim, Gozal

1987-01-01

Salt-tolerant selected cells of Shamouti orange (Citrus sinensis) and Sour orange (Citrus aurantium) grew considerably better than nonselected cells at any NaCl concentration tested up to 200 millimolar. Also, the growth response of each treatment was identical in the two species. However, the performance of cells of the two species under osmotic stress induced by polyethylene glycol (PEG), which is presumably a nonabsorbed osmoticum, was significantly different. The nonselected Shamouti cell lines were significantly more sensitive to osmotic stress than the selected cells. The salt adapted Shamouti cells were apparently also adapted to osmotic stress induced by PEG. In Sour orange, however, the selected lines had no advantage over the nonselected line in response to osmotic stress induced by PEG. This response was also similar quantitatively to the response of the selected salt-tolerant Shamouti cell line. It seems that the tolerance to salt in Shamouti, a partial salt excluder, involves an osmotic adaptation, whereas in Sour orange, a salt accumulator, such an adaptation apparently does not occur. PEG-induced osmotic stress causes an increase in the percent dry weight of salt-sensitive and salt-tolerant cells of both species. No such increase was found under salt stress. The size of control and stressed cells is not significantly different. PMID:16665715

Safety and durability of low-density polyethylene bags in solar water disinfection applications.

PubMed

Danwittayakul, Supamas; Songngam, Supachai; Fhulua, Tipawan; Muangkasem, Panida; Sukkasi, Sittha

2017-08-01

Solar water disinfection (SODIS) is a simple point-of-use process that uses sunlight to disinfect water for drinking. Polyethylene terephthalate (PET) bottles are typically used as water containers for SODIS, but a new SODIS container design has recently been developed with low-density polyethylene (LDPE) bags and can overcome the drawbacks of PET bottles. Two nesting layers of LDPE bags are used in the new design: the inner layer containing the water to be disinfected and the outer one creating air insulation to minimize heat loss from the water to the surroundings. This work investigated the degradation of LDPE bags used in the new design in actual SODIS conditions over a period of 12 weeks. The degradation of the LDPE bags was investigated weekly using a scanning electron microscope, Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometer, and tensile strength tester. It was found that the LDPE bags gradually degraded under the sunlight due to photo-oxidation reactions, especially in the outer bags, which were directly exposed to the sun and surroundings, leading to the reduction of light transmittance (by 11% at 300 nm) and tensile strength (by 33%). In addition, possible leaching of organic compounds into the water contained in the inner bags was examined using gas chromatography-mass spectrometer. 2,4-Di-tert-butylphenol was found in some SODIS water samples as well as the as-received water samples, in the concentration range of 1-4 μg/L, which passes the Environmental Protection Agency Drinking Water Guidance on Disinfection By-Products.

Plastic wastes as modifiers of the thermoplasticity of coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

M.A. Diez; C. Barriocanal; R. Alvarez

2005-12-01

Plastic waste recycling represents a major challenge in environmental protection with different routes now available for dealing with mechanical, chemical, and energy recycling. New concepts in plastic waste recycling have emerged so that now such wastes can be used to replace fossil fuels, either as an energy source or as a secondary raw material. Our objective is to explore the modification of the thermoplastic properties of coal in order to assess the possibility of adding plastic waste to coal for the production of metallurgical coke. Two bituminous coals of different rank and thermoplastic properties were used as a base componentmore » of blends with plastic wastes such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), poly(ethylene terephthalate) (PET), and acrilonitrile-butadiene-styrene copolymer (ABS). In all cases, the addition of plastic waste led to a reduction in Gieseler maximum fluidity, the extent of the reduction depending on the fluidity of the base coal, and the amount, the molecular structure, and the thermal behavior of the polymer. As a consequence, the amount of volatile matter released by the plastic waste before, during, and after the maximum fluidity of the coal and the hydrogen-donor and hydrogen-acceptor capacities of the polymer were concluded to be key factors in influencing the extent of the reduction in fluidity and the development of anisotropic carbons. The incorporation of the plastic to the carbon matrix was clearly established in semicokes produced from blends of a high-fluid coal and the plastic tested by SEM examination. 42 refs., 10 figs., 7 tabs.« less

Elimination of polycyclic aromatic hydrocarbons from smoked sausages by migration into polyethylene packaging.

PubMed

Semanová, Jana; Skláršová, Božena; Šimon, Peter; Šimko, Peter

2016-06-15

The objective of this work was a study of interactions between a smoked meat product and plastic packaging to find a possibility of elimination of polycyclic aromatic hydrocarbons (PAH) from smoked sausages by migration into the packaging. Smoked meat sausages were packed into o-polyamide/low density polyethylene laminated film and content of four PAH was determined at 0, 15, 30, 45, 60, 75, 90, 120, 150 and 180 min by HPLC. During this time, total PAH4 content decreased from 30.1 to 5.7 μg/kg, benzo[a]anthracene decreased from 11.5 to 2.1 μg/kg, chrysene from 9.4 to 1.9 μg/kg, benzo[b]fluoranthene from 5.3 to 0.6 μg/kg and benzo[a]pyrene from 3.9 to 1.1 μg/kg while PAH4 content in non-packed sausages remained at a constant level. So, while sausages did not meet European safety limits set for PAH4 content of 12 μg/kg and 2 μg/kg for benzo[a]pyrene before packaging, these limits were met at the end of the experiment. This decrease was brought about by migration of PAH4 from sausages into low density polyethylene packaging bulk and the measure of decrease can be predicted by a kinetic equation, making it possible to calculate PAH content equal to any time of experiment as well as the time of interaction necessary to fulfil EU legislative limits. Copyright © 2016 Elsevier Ltd. All rights reserved.

Relationships Analysis and Public Perception of the Healthy Plastic as One Solution to Healthy Living

NASA Astrophysics Data System (ADS)

Hartatik; Hartono, R.; Purnomo, A.; Riasti, B. K.; Munawaroh, H.

2017-02-01

Direct Plastics are used for various human purposes, ranging from household to industry. Tableware and drink made of plastic is very practical to use, easy to clean, durable and cost far less than tableware made of the other material. However, must also be considered in terms of security in the use of plastic containers for food storage because there are adverse effects. There are seven types of plastic based material used, namely Polyethylene, Terephthalate, High Density Polyethylene, Polyvinyl Chloride or V/PVC, Low Density Polyethylene or LDPE, Polypropylene, Polystyrene, Plastics others including polycarbonate. Experts claims that the plastic code numbers 2, 4 and 5 are used for equipment safely eat/drink because it is more stable and safe if used correctly. In this study will analyze the relationship between the recent education, family income to perception and behavior in the use of plastics in food storage daily as one solution to healthy living. The population of this research is all the people in the Solo area particularly housewife and all the people in the productive age. Data were obtained through a survey with cluster random sampling method. Statistical method used is a parametric method and Chi Square test This method is used as an alternative method of parametric when some assumptions are not met. Based on the results of Chi Square test with α = 15% was concluded that recent education and income related to the behavior of people using plastic products as one of the solutions to Healthy Living.

Microstructural modifications induced by accelerated aging and lipid absorption in remelted and annealed UHMWPEs for total hip arthroplasty

PubMed Central

Puppulin, Leonardo; Zhu, Wenliang; Sugano, Nobuhiko

2014-01-01

Three types of commercially available ultra-high molecular weight polyethylene (UHMWPE) acetabular cups currently used in total hip arthroplasty have been studied by means of Raman micro-spectroscopy to unfold the microstructural modification induced by the oxidative degradation after accelerated aging with and without lipid absorption. The three investigated materials were produced by three different manufacturing procedures, as follows: irradiation followed by remelting, one-step irradiation followed by annealing, 3-step irradiation and annealing. Clear microstructural differences were observed in terms of phase contents (i.e. amorphous, crystalline and intermediate phase fraction). The three-step annealed material showed the highest crystallinity fraction in the bulk, while the remelted polyethylene is clearly characterized by the lowest content of crystalline phase and the highest content of amorphous phase. After accelerated aging either with or without lipids, the amount of amorphous phase decreased in all the samples as a consequence of the oxidation-induced recrystallization. The most remarkable variations of phase contents were detected in the remelted and in the single-step annealed materials. The presence of lipids triggered oxidative degradation especially in the remelted polyethylene. Such experimental evidence might be explained by the highest amount of amorphous phase in which lipids can be absorbed prior to accelerated aging. The results of these spectroscopic characterizations help to rationalize the complex effect of different irradiation and post-irradiation treatments on the UHMWPE microstructure and gives useful information on how significantly any single step of the manufacturing procedures might affect the oxidative degradation of the polymer. PMID:25179830

Mutant CCL2 Protein Coating Mitigates Wear Particle-Induced Bone Loss in a Murine Continuous Polyethylene Infusion Model

PubMed Central

Nabeshima, Akira; Pajarinen, Jukka; Lin, Tzu-hua; Jiang, Xinyi; Gibon, Emmanuel; Córdova, Luis A.; Loi, Florence; Lu, Laura; Jämsen, Eemeli; Egashira, Kensuke; Yang, Fan; Yao, Zhenyu; Goodman, Stuart B

2016-01-01

Wear particle-induced osteolysis limits the long-term survivorship of total joint replacement (TJR). Monocyte/macrophages are the key cells of this adverse reaction. Monocyte Chemoattractant Protein-1 (MCP-1/CCL2) is the most important chemokine regulating trafficking of monocyte/macrophages in particle-induced inflammation. 7ND recombinant protein is a mutant of CCL2 that inhibits CCL2 signaling. We have recently developed a layer-by-layer (LBL) coating platform on implant surfaces that can release biologically active 7ND. In this study, we investigated the effect of 7ND on wear particle-induced bone loss using the murine continuous polyethylene (PE) particle infusion model with 7ND coating of a titanium rod as a local drug delivery device. PE particles were infused into hollow titanium rods with or without 7ND coating implanted in the distal femur for 4 weeks. Specific groups were also injected with RAW 264.7 as the reporter macrophages. Wear particle-induced bone loss and the effects of 7ND were evaluated by microCT, immunohistochemical staining, and bioluminescence imaging. Local delivery of 7ND using the LBL coating decreased systemic macrophage recruitment, the number of osteoclasts and wear particle-induced bone loss. The development of a novel orthopaedic implant coating with anti-CCL2 protein may be a promising strategy to mitigate peri-prosthetic osteolysis. PMID:27918885

Automotive battery energy density — past, present and future

NASA Astrophysics Data System (ADS)

Peters, K.

Energy and power densities of automotive batteries at engine starting rates have doubled over the past twenty years. Most recent improvements can be credited to the use of both very thin plates with optimized grid design and low-resistance polyethylene separators with a thin backweb and a reduced rib height. Opportunities for further improvements using the same design approach and similar processing techniques are limited. The effect of some recent innovative developments on weight reduction and performance improvement are reviewed, together with possible changes to the electrical system of vehicles.

Does cyclic stress and accelerated ageing influence the wear behavior of highly crosslinked polyethylene?

PubMed

Affatato, Saverio; De Mattia, Jonathan Salvatore; Bracco, Pierangiola; Pavoni, Eleonora; Taddei, Paola

2016-06-01

First-generation (irradiated and remelted or annealed) and second-generation (irradiated and vitamin E blended or doped) highly crosslinked polyethylenes were introduced in the last decade to solve the problems of wear and osteolysis. In this study, the influence of the Vitamin-E addition on crosslinked polyethylene (XLPE_VE) was evaluated by comparing the in vitro wear behavior of crosslinked polyethylene (XLPE) versus Vitamin-E blended polyethylene XLPE and conventional ultra-high molecular weight polyethylene (STD_PE) acetabular cups, after accelerated ageing according to ASTM F2003-02 (70.0±0.1°C, pure oxygen at 5bar for 14 days). The test was performed using a hip joint simulator run for two millions cycles, under bovine calf serum as lubricant. Mass loss was found to decrease along the series XLPE_VE>STD_PE>XLPE, although no statistically significant differences were found between the mass losses of the three sets of cups. Micro-Raman spectroscopy was used to investigate at a molecular level the morphology changes induced by wear. The spectroscopic analyses showed that the accelerated ageing determined different wear mechanisms and molecular rearrangements during testing with regards to the changes in both the chain orientation and the distribution of the all-trans sequences within the orthorhombic, amorphous and third phases. The results of the present study showed that the addition of vitamin E was not effective to improve the gravimetric wear of PE after accelerated ageing. However, from a molecular point of view, the XLPE_VE acetabular cups tested after accelerated ageing appeared definitely less damaged than the STD_PE ones and comparable to XLPE samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced energy density and thermal conductivity in poly(fluorovinylidene-co-hexafluoropropylene) nanocomposites incorporated with boron nitride nanosheets exfoliated under assistance of hyperbranched polyethylene.

PubMed

Ye, Huijian; Lu, Tiemei; Xu, Chunfeng; Zhong, Mingqiang; Xu, Lixin

2018-03-02

Polymer dielectric film with a large dielectric constant, high energy density and enhanced thermal conductivity are of significance for the development of impulse capacitors. However, the fabrication of polymer dielectrics combining high energy density and thermal conductivity is still a challenge at the moment. Here we demonstrate the facile exfoliation of hexagonal boron nitride nanosheets (BNNSs) in common organic solvents under sonication with the assistance of hyperbranched polyethylene (HBPE). The noncovalent CH-π interactions between the nanosheets and HBPE ensure the dispersion of BNNSs in organic solvents with high concentrations, because of the highly branched chain structure of HBPE. Subsequently, the resultant BNNSs with a few defects are distributed uniformly in the poly(fluorovinylidene-co-hexafluoropropylene) (P(VDF-HFP)) nanocomposite films prepared via simple solution casting. The BNNS/P(VDF-HFP) nanocomposite exhibits outstanding dielectric properties, high energy density and high thermal conductivity. The dielectric constant of the 0.5 wt% nanocomposite film is 35.5 at 100 Hz with an energy density of 5.6 J cm -3 at 325 MV m -1 and a high charge-discharge efficiency of 79% due to the depression of the charge injection and chemical species ionization in a high field. Moreover, a thermal conductivity of 1.0 wt% nanocomposite film reaches 0.91 W·m -1  · K -1 , which is 3.13 times higher than that of the fluoropolymer matrix. With dipole accumulation and orientation in the interfacial zone, lightweight, flexible BNNS/P(VDF-HFP) nanocomposite films with high charge-discharge performance and thermal conductivity, exhibit promising applications in relatively high-temperature electronics and energy storage devices.

Enhanced energy density and thermal conductivity in poly(fluorovinylidene-co-hexafluoropropylene) nanocomposites incorporated with boron nitride nanosheets exfoliated under assistance of hyperbranched polyethylene

NASA Astrophysics Data System (ADS)

Ye, Huijian; Lu, Tiemei; Xu, Chunfeng; Zhong, Mingqiang; Xu, Lixin

2018-03-01

Polymer dielectric film with a large dielectric constant, high energy density and enhanced thermal conductivity are of significance for the development of impulse capacitors. However, the fabrication of polymer dielectrics combining high energy density and thermal conductivity is still a challenge at the moment. Here we demonstrate the facile exfoliation of hexagonal boron nitride nanosheets (BNNSs) in common organic solvents under sonication with the assistance of hyperbranched polyethylene (HBPE). The noncovalent CH-π interactions between the nanosheets and HBPE ensure the dispersion of BNNSs in organic solvents with high concentrations, because of the highly branched chain structure of HBPE. Subsequently, the resultant BNNSs with a few defects are distributed uniformly in the poly(fluorovinylidene-co-hexafluoropropylene) (P(VDF-HFP)) nanocomposite films prepared via simple solution casting. The BNNS/P(VDF-HFP) nanocomposite exhibits outstanding dielectric properties, high energy density and high thermal conductivity. The dielectric constant of the 0.5 wt% nanocomposite film is 35.5 at 100 Hz with an energy density of 5.6 J cm-3 at 325 MV m-1 and a high charge-discharge efficiency of 79% due to the depression of the charge injection and chemical species ionization in a high field. Moreover, a thermal conductivity of 1.0 wt% nanocomposite film reaches 0.91 W·m-1 · K-1, which is 3.13 times higher than that of the fluoropolymer matrix. With dipole accumulation and orientation in the interfacial zone, lightweight, flexible BNNS/P(VDF-HFP) nanocomposite films with high charge-discharge performance and thermal conductivity, exhibit promising applications in relatively high-temperature electronics and energy storage devices.

Cellulose nanocrystal/polyolefin biocomposites prepared by solid-state shear pulverization: Superior dispersion leading to synergistic property enhancements

Treesearch

Krishnan A. Iyer; Gregory T. Schueneman; John M. Torkelson

2015-01-01

Cellulose nanocrystals (CNCs), a class of renewable bionanomaterials with excellent mechanical properties, have gained major interest as filler for polymers. However, challenges associated with effective CNC dispersion have hindered the production of composites with desired property enhancements. Here, composites of polypropylene (PP) and low density polyethylene (LDPE...

Accelerated weathering of natural fiber-thermoplastic composites : effects of ultraviolet exposure on bending strength and stiffness

Treesearch

Thomas Lundin; Robert H. Falk; Colin Felton

2002-01-01

Mechanical properties of bending stiffness and yield stress were used to evaluate the effects of ultraviolet exposure on natural fiber-thermoplastic composites. Four different specimen formulations were evaluated. Injection molded high density polyethylene (HDPE) served as the polymer base for all formulations. Two lignocellulosic fillers, wood flour and kenaf fiber,...

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: STORMWATER SOURCE AREA TREATMENT DEVICE — BAYSAVER TECHNOLOGIES, INC. BAYSAVER SEPARATION SYSTEM, MODEL 10K

EPA Science Inventory

Verification testing of the BaySaver Separation System, Model 10K was conducted on a 10 acre drainage basin near downtown Griffin, Georgia. The system consists of two water tight pre-cast concrete manholes and a high-density polyethylene BaySaver Separator Unit. The BaySaver Mod...

40 CFR Appendix A-8 to Part 60 - Test Methods 26 through 30B

Code of Federal Regulations, 2010 CFR

2010-07-01

... glass connectors. Silicone grease may be used, if necessary, to prevent leakage. For sampling at high... or glass, 500-ml or larger, two. 6.2.2Storage Bottles. 100- or 250-ml, high-density polyethylene... determinations, and upon availability, audit samples may be obtained from the appropriate EPA regional Office or...

40 CFR 52.420 - Identification of plan.

Code of Federal Regulations, 2010 CFR

2010-07-01

... availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register.../Registration Prohibited 6/1/97 1/13/00, 65 FR 2048 Section 8 Availability of Permit/Registration 6/1/97 1/13/00... 21707 Section 41 Manufacture of High-Density Polyethylene, Polypropylene and Polystyrene Resins 1/11/93...

Hot water extracted wood fiber for production of wood plastic composites (WPCs)

Treesearch

Manuel Raul Pelaez-Samaniego; Vikram Yadama; Eini Lowell; Thomas E. Amidon; Timothy L. Chaffee

2013-01-01

Undebarked ponderosa pine chips were treated by hot water extraction to modify the chemical composition. In the treated pine (TP) , the mass was reduced by approximately 20%, and the extract was composed mainly of degradation products of hemicelluloses. Wood flour produced from TP and unextracted chips (untreated pine, UP) was blended with high-density polyethylene (...

1,3-dichloropropene and chloropicrin emissions following simulated drip irrigation to raised beds under plastic films

USDA-ARS?s Scientific Manuscript database

Using laboratory soil chambers a non-scaled representation of an agricultural raised bed was constructed. For a sandy loam soil, a drip application of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) under both high density polyethylene (HDPE) and virtually impermeable film (VIF) was performed at 5...

Oxidation and biodegradation of polyethylene films containing pro-oxidantadditives: Synergistic effects of sunlight exposure, thermal aging and fungal biodegradation

USDA-ARS?s Scientific Manuscript database

Synergistic effects of sunlight exposure, thermal aging and fungal biodegradation on the oxidation and biodegradation of linear low density poly (ethylene) PE-LLD films containing pro-oxidant were examined. To achieve oxidation and degradation, films were first exposed to the sunlight for 93 days du...

Changes in wood flour/HDPE composites after accelerated weathering with and without water spray

Treesearch

Nicole M. Stark

2005-01-01

Wood-plastic lumber is promoted as a low-maintenance high-durability product. After weathering, however, wood-plasticcomposites (WPCs) often fide and lose mechanical properties. In the first part ofthis study, 50%wood-flour-filled high-density polyethylene (HDPE) composite samples were injection molded or extruded. Composites were exposed to two accelerated weathering...

X-ray diffraction and reflectivity validation of the depletion attraction in the competitive adsorption of lung surfactant and albumin.

PubMed

Stenger, Patrick C; Wu, Guohui; Miller, Chad E; Chi, Eva Y; Frey, Shelli L; Lee, Ka Yee C; Majewski, Jaroslaw; Kjaer, Kristian; Zasadzinski, Joseph A

2009-08-05

Lung surfactant (LS) and albumin compete for the air-water interface when both are present in solution. Equilibrium favors LS because it has a lower equilibrium surface pressure, but the smaller albumin is kinetically favored by faster diffusion. Albumin at the interface creates an energy barrier to subsequent LS adsorption that can be overcome by the depletion attraction induced by polyethylene glycol (PEG) in solution. A combination of grazing incidence x-ray diffraction (GIXD), x-ray reflectivity (XR), and pressure-area isotherms provides molecular-resolution information on the location and configuration of LS, albumin, and polymer. XR shows an average electron density similar to that of albumin at low surface pressures, whereas GIXD shows a heterogeneous interface with coexisting LS and albumin domains at higher surface pressures. Albumin induces a slightly larger lattice spacing and greater molecular tilt, similar in effect to a small decrease in the surface pressure. XR shows that adding PEG to the LS-albumin subphase restores the characteristic LS electron density profile at the interface, and confirms that PEG is depleted near the interface. GIXD shows the same LS Bragg peaks and Bragg rods as on a pristine interface, but with a more compact lattice corresponding to a small increase in the surface pressure. These results confirm that albumin adsorption creates a physical barrier that inhibits LS adsorption, and that PEG in the subphase generates a depletion attraction between the LS aggregates and the interface that enhances LS adsorption without substantially altering the structure or properties of the LS monolayer.

Toughening and its association with the postharvest quality of king oyster mushroom (Pleurotus eryngii) stored at low temperature.

PubMed

Li, Danqing; Qin, Xiaoyi; Tian, Pingping; Wang, Jie

2016-04-01

Toughening-induced textural decay easily occurs in stored mushrooms. The objective of this study was to investigate the textural alteration caused by toughening in relation to other quality attributes of king oyster mushroom (Pleurotus eryngii). Fresh king oyster mushrooms, packed in low-density polyethylene bags, were stored at different low temperatures for 18 days to measure textural and other quality attributes. It was found that toughening occurred twice during the entire storage time. Highly associated change profiles were observed for the lignin content and activities of three important enzymes involved in lignin synthesis. The chitin and cellulose contents exhibited low correlation with toughening. Malondialdehyde content, electrolyte leakage rate and total phenolics content appeared to be related to toughening, but the browning index showed a negative correlation with toughening. Our results suggested that toughening may be mainly caused by lignification and can affect the postharvest quality of the tested mushrooms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Controlling Short-Range Interactions by Tuning Surface Chemistry in HDPE/Graphene Nanoribbon Nanocomposites.

PubMed

Sadeghi, Soheil; Zehtab Yazdi, Alireza; Sundararaj, Uttandaraman

2015-09-03

Unique dispersion states of nanoparticles in polymeric matrices have the potential to create composites with enhanced mechanical, thermal, and electrical properties. The present work aims to determine the state of dispersion from the melt-state rheological behavior of nanocomposites based on carbon nanotube and graphene nanoribbon (GNR) nanomaterials. GNRs were synthesized from nitrogen-doped carbon nanotubes via a chemical route using potassium permanganate and some second acids. High-density polyethylene (HDPE)/GNR nanocomposite samples were then prepared through a solution mixing procedure. Different nanocomposite dispersion states were achieved using different GNR synthesis methods providing different surface chemistry, interparticle interactions, and internal compartments. Prolonged relaxation of flow induced molecular orientation was observed due to the presence of both carbon nanotubes and GNRs. Based on the results of this work, due to relatively weak interactions between the polymer and the nanofillers, it is expected that short-range interactions between nanofillers play the key role in the final dispersion state.

Low-cost flexible supercapacitors based on laser reduced graphene oxide supported on polyethylene terephthalate substrate

NASA Astrophysics Data System (ADS)

Ghoniem, Engy; Mori, Shinsuke; Abdel-Moniem, Ahmed

2016-08-01

A controlled high powered CO2 laser system is used to reduce and pattern graphene oxide (GO) film supported onto a flexible polyethylene terephthalate (PET) substrate. The laser reduced graphene oxide (rGO) film is characterized and evaluated electrochemically in the absence and presence of an overlying anodicaly deposited thin film of pseuodcapactive MnO2 as electrodes for supercapacitor applications using aqueous electrolyte. The laser treatment of the GO film leads to an overlapped structure of defective multi-layer rGO sheets with an electrical conductivity of 273 S m-1. The rGO and MnO2/rGO electrodes exhibit specific capacitance in the range of 82-107 and 172-368 Fg-1 at applied current range of 0.1-1.0 mA cm-2 and retain 98 and 95% of their initial capacitances after 2000 cycles at a current density of 1.0 mA cm-2, respectively. Also, the rGO is assigned as an electrode material for flexible conventionally stacked and interdigitated in-plane supercapacitor structures using gel electrolyte. Three electrode architectures of 2, 4, and 6 sub-electrodes are studied for the interdigital in-plane design. The device with interdigital 6 sub-electrodes architecture I-PS(6) delivers power density of 537.1 Wcm-3 and an energy density of 0.45 mWh cm-3.

Easy sperm processing technique allowing exclusive accumulation and later usage of DNA-strandbreak-free spermatozoa.

PubMed

Ebner, T; Shebl, O; Moser, M; Mayer, R B; Arzt, W; Tews, G

2011-01-01

Sperm DNA fragmentation is increased in poor-quality semen samples and correlates with failed fertilization, impaired preimplantation development and reduced pregnancy outcome. Common sperm preparation techniques may reduce the percentage of strandbreak-positive spermatozoa, but, to date, there is no reliable approach to exclusively accumulate strandbreak-free spermatozoa. To analyse the efficiency of special sperm selection chambers (Zech-selectors made of glass or polyethylene) in terms of strandbreak reduction, 39 subfertile men were recruited and three probes (native, density gradient and Zech-selector) were used to check for strand breaks using the sperm chromatin dispersion test. The mean percentage of affected spermatozoa in the ejaculate was 15.8 ± 7.8% (range 5.0–42.1%). Density gradient did not significantly improve the quality of spermatozoa selected(14.2 ± 7.0%). However, glass chambers completely removed 90% spermatozoa showing strand breaks and polyethylene chambers removed 76%. Both types of Zech-selectors were equivalent in their efficiency, significantly reduced DNA damage (P < 0.001) and,with respect to this, performed better than density gradient centrifugation (P < 0.001). As far as is known, this is the first report ona sperm preparation technique concentrating spermatozoa unaffected in terms of DNA damage. The special chambers most probably select for sperm motility and/or maturity. Copyright © 2010 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Toward High-Performance Lithium-Sulfur Batteries: Upcycling of LDPE Plastic into Sulfonated Carbon Scaffold via Microwave-Promoted Sulfonation.

PubMed

Kim, Patrick J; Fontecha, Harif D; Kim, Kyungho; Pol, Vilas G

2018-05-02

Lithium-sulfur batteries were intensively explored during the last few decades as next-generation batteries owing to their high energy density (2600 Wh kg -1 ) and effective cost benefit. However, systemic challenges, mainly associated with polysulfide shuttling effect and low Coulombic efficiency, plague the practical utilization of sulfur cathode electrodes in the battery market. To address the aforementioned issues, many approaches have been investigated by tailoring the surface characteristics and porosities of carbon scaffold. In this study, we first present an effective strategy of preparing porous sulfonated carbon (PSC) from low-density polyethylene (LDPE) plastic via microwave-promoted sulfonation. Microwave process not only boosts the sulfonation reaction of LDPE but also induces huge amounts of pores within the sulfonated LDPE plastic. When a PSC layer was utilized as an interlayer in lithium-sulfur batteries, the sulfur cathode delivered an improved capacity of 776 mAh g -1 at 0.5C and an excellent cycle retention of 79% over 200 cycles. These are mainly attributed to two materialistic benefits of PSC: (a) porous structure with high surface area and (b) negatively charged conductive scaffold. These two characteristics not only facilitate the improved electrochemical kinetics but also effectively block the diffusion of polysulfides via Coulomb interaction.

Desolvation of polymers by ultrafast heating: Influence of hydrophilicity

NASA Astrophysics Data System (ADS)

Sun, Si Neng; Urbassek, Herbert M.

2010-10-01

Using molecular-dynamics simulation, we investigate the consequences of ultrafast laser-induced heating of a small water droplet containing a solvated polymer. Two polymers are studied: polyethylene as an example of a hydrophobic, and polyketone as an example of a hydrophilic polymer. In both cases, when the droplet is heated below the critical temperature of water, strong water evaporation is started, but the polymer remains in contact with a central water cluster. However, upon heating beyond the critical temperature, the hydrophilic polyethylene becomes completely desolvated, while polyketone still remains solvated. We analyze this behavior in terms of the intermolecular interactions and of the expansion dynamics of the heated droplet.

Comparing Single-Point and Multi-point Calibration Methods in Modulated DSC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Buskirk, Caleb Griffith

2017-06-14

Heat capacity measurements for High Density Polyethylene (HDPE) and Ultra-high Molecular Weight Polyethylene (UHMWPE) were performed using Modulated Differential Scanning Calorimetry (mDSC) over a wide temperature range, -70 to 115 °C, with a TA Instruments Q2000 mDSC. The default calibration method for this instrument involves measuring the heat capacity of a sapphire standard at a single temperature near the middle of the temperature range of interest. However, this method often fails for temperature ranges that exceed a 50 °C interval, likely because of drift or non-linearity in the instrument's heat capacity readings over time or over the temperature range. Therefore,more » in this study a method was developed to calibrate the instrument using multiple temperatures and the same sapphire standard.« less

Controlled Emissivity Coatings to Delay Ignition of Polyethylene

PubMed Central

Sonnier, Rodolphe; Ferry, Laurent; Gallard, Benjamin; Boudenne, Abderrahim; Lavaud, François

2015-01-01

Semi-opaque to opaque films containing small amounts of various aluminium particles to decrease emissivity were easily prepared and coated onto low-density polyethylene (LDPE) sheets. The thermal-radiative properties (reflectivity, transmissivity and absorptivity) of the films were measured and related to the aluminum particles’ content, size and nature. Time-to-ignition of samples was assessed using a cone calorimeter at different heat flux values (35, 50 and 75 kW/m2). The coatings allowed significant ignition delay and, in some cases, changed the material behaviour from thermally thin to thick behaviour. These effects are related both to their emissivity and transmissivity. A lower emissivity, which decreases during the degradation, and a lower transmissivity are the key points to ensure an optimal reaction-to-fire. PMID:28793609

Recycling and processing of several typical crosslinked polymer scraps with enhanced mechanical properties based on solid-state mechanochemical milling

NASA Astrophysics Data System (ADS)

Lu, Canhui; Zhang, Xinxing; Zhang, Wei

2015-05-01

The partially devulcanization or de-crosslinking of ground tire rubber (GTR), post-vulcanized fluororubber scraps and crosslinked polyethylene from cable scraps through high-shear mechanochemical milling (HSMM) was conducted by a modified solid-state mechanochemical reactor. The results indicated that the HSMM treated crosslinked polymer scraps can be reprocessed as virgin rubbers or thermoplastics to produce materials with high performance. The foamed composites of low density polyethylene/GTR and the blend of post-vulcanized flurorubber (FKM) with polyacrylate rubber (ACM) with better processability and mechanical properties were obtained. The morphology observation showed that the dispersion and compatibility between de-crosslinked polymer scraps and matrix were enhanced. The results demonstrated that HSMM is a feasible alternative technology for recycling post-vulcanized or crosslinked polymer scraps.

NRC, SPI, and chasing arrows: Is there common ground

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rabasca, L.

After negotiating for 15 months, issuing three white papers, and conducting consumer research, the National Recycling Coalition (NRC, Washington, DC) and the Society of the Plastics Industry, Inc. (SPI, Washington, DC), have agreed to disagree on the use of the familiar chasing arrows logo in SPI's seven-number resin identification code. The desired end result of the talks and debates was supposed to be a plan to change legislation requiring 39 states to use SPI's current resin identification code and a commitment to remove the old code from durable goods and flexible packaging. Ultimately, these actions could have improved markets formore » polyethylene terephthalate (PET) and high-density polyethylene (HDPE) by reducing contamination caused by confusion over what is actually recycled versus what is merely recyclable.« less

Aqueous Synthesis of PEGylated Quantum Dots with Increased Colloidal Stability and Reduced Cytotoxicity.

PubMed

Ulusoy, Mehriban; Jonczyk, Rebecca; Walter, Johanna-Gabriela; Springer, Sergej; Lavrentieva, Antonina; Stahl, Frank; Green, Mark; Scheper, Thomas

2016-02-17

Ligands used on the surface of colloidal nanoparticles (NPs) have a significant impact on physiochemical properties of NPs and their interaction in biological environments. In this study, we report a one-pot aqueous synthesis of 3-mercaptopropionic acid (MPA)-functionalized CdTe/CdS/ZnS quantum dots (Qdots) in the presence of thiol-terminated methoxy polyethylene glycol (mPEG) molecules as a surface coordinating ligand. The resulting mPEG-Qdots were characterized by using ζ potential, FTIR, thermogravimetric (TG) analysis, and microscale thermophoresis (MST) studies. We investigated the effect of mPEG molecules and their grafting density on the Qdots photophysical properties, colloidal stability, protein binding affinity, and in vitro cellular toxicity. Moreover, cellular binding features of the resulting Qdots were examined by using three-dimensional (3D) tumor-like spheroids, and the results were discussed in detail. Promisingly, mPEG ligands were found to increase colloidal stability of Qdots, reduce adsorption of proteins to the Qdot surface, and mitigate Qdot-induced side effects to a great extent. Flow cytometry and confocal microscopy studies revealed that PEGylated Qdots exhibited distinctive cellular interactions with respect to their mPEG grafting density. As a result, mPEG molecules demonstrated a minimal effect on the ZnS shell deposition and the Qdot fluorescence efficiency at a low mPEG density, whereas they showed pronounced effect on Qdot colloidal stability, protein binding affinity, cytotoxicity, and nonspecific binding at a higher mPEG grafting amount.

Implosion dynamics of condensed Z-pinch at the Angara-5-1 facility

NASA Astrophysics Data System (ADS)

Aleksandrov, V. V.; Grabovski, E. V.; Gritsuk, A. N.; Volobuev, I. V.; Kazakov, E. D.; Kalinin, Yu. G.; Korolev, V. D.; Laukhin, Ya. I.; Medovshchikov, S. F.; Mitrofanov, K. N.; Oleinik, G. M.; Pimenov, V. G.; Smirnova, E. A.; Ustroev, G. I.; Frolov, I. N.

2017-08-01

The implosion dynamics of a condensed Z-pinch at load currents of up to 3.5 MA and a current rise time of 100 ns was studied experimentally at the Angara-5-1 facility. To increase the energy density, 1- to 3-mm-diameter cylinders made of a deuterated polyethylene-agar-agar mixture or microporous deuterated polyethylene with a mass density of 0.03-0.5 g/cm3 were installed in the central region of the loads. The plasma spatiotemporal characteristics were studied using the diagnostic complex of the Angara-5-1 facility, including electron-optical streak and frame imaging, time-integrated X-ray imaging, soft X-ray (SXR) measurements, and vacuum UV spectroscopy. Most information on the plasma dynamics was obtained using a ten-frame X-ray camera ( E > 100 eV) with an exposure of 4 ns. SXR pulses were recorded using photoemissive vacuum X-ray detectors. The energy characteristics of neutron emission were measured using the time-offlight method with the help of scintillation detectors arranged along and across the pinch axis. The neutron yield was measured by activation detectors. The experimental results indicate that the plasma dynamics depends weakly on the load density. As a rule, two stages of plasma implosion were observed. The formation of hot plasma spots in the initial stage of plasma expansion from the pinch axis was accompanied by short pulses of SXR and neutron emission. The neutron yield reached (0.4-3) × 1010 neutrons/shot and was almost independent of the load density due to specific features of Z-pinch dynamics.

Synergistic effect of calcium stearate and photo treatment on the rate of biodegradation of low density polyethylene spent saline vials.

PubMed

Carol, D; Karpagam, S; Kingsley, S J; Vincent, S

2012-07-01

The biodegradation of spent saline bottles, a low density polyethylene product (LDPE) by two selected Arthrobacter sp. under in vitro conditions is reported. Chemical and UV pretreatment play a vital role in enhancing the rate of biodegradation. Treated LDPE film exhibits a higher weight loss and density when compared to untreated films. Arthrobacter oxydans and Arthrobacter globiformis grew better in medium containing pretreated film than in medium containing untreated film. The decrease in density and weight loss of LDPE was also more for pretreated film when compared to untreated film indicating the affect of abiotic treatment on mechanical properties of LDPE. The decrease in the absorbance corresponding to carbonyl groups and double bonds that were generated during pretreatment suggest that some of the double bonds were cut by Arthrobacter species. Since Arthrobacter sp. are capable of degrading urea, splitting of urea group were also seen in FTIR spectrum indicating the evidence of biodegradation after microbial incubation. The results indicated that biodegradation rate could be enhanced by exposing LDPE to calcium stearate (a pro-oxidant) which acts as an initiator for the oxidation of the polymers leading to a decrease of molecular weight and formation of hydrophilic group. Therefore, the initial step for biodegradation of many inert polymers depends on a photo-oxidation of those polymers. The application in sufficient details with improved procedures utilizing recombinant microorganism with polymer degradation capacity can lead to a better plastic waste management in biomedical field. The present plastic disposal trend of waste accumulation can be minimized with this promising eco-friendly technique.

Fabrication, characterization and gamma rays shielding properties of nano and micro lead oxide-dispersed-high density polyethylene composites

NASA Astrophysics Data System (ADS)

Mahmoud, Mohamed E.; El-Khatib, Ahmed M.; Badawi, Mohamed S.; Rashad, Amal R.; El-Sharkawy, Rehab M.; Thabet, Abouzeid A.

2018-04-01

Polymer composites of high-density polyethylene (HD-PE) filled with powdered lead oxide nanoparticles (PbO NPs) and bulk lead oxide (PbO Blk) were prepared with filler weight fraction [10% and 50%]. These polymer composites were investigated for radiation-shielding of gamma-rays emitted from radioactive point sources [241Am, 133Ba, 137Cs, and 60Co]. The polymer was found to decrease the heaviness of the shielding material and increase the flexibility while the metal oxide fillers acted as principle radiation attenuators in the polymer composite. The prepared composites were characterized by Fourier transform infrared spectrophotometer (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), Brunauer-Emmett-Teller surface area (BET) and field emission transmission electron microscope (FE-TEM). The morphological analysis of the assembled composites showed that, PbO NPs and PbO Blk materials exhibited homogenous dispersion in the polymer-matrix. Thermogravimetric analysis (TGA) demonstrated that the thermal-stability of HD-PE was enhanced in the presence of both PbO Blk and PbO NPs. The results declared that, the density of polymer composites was increase with the percentage of filler contents. The highest density value was identified as 1.652 g cm-3 for 50 wt% of PbO NPs. Linear attenuation coefficients (μ) have been estimated from the use of XCOM code and measured results. Reasonable agreement was attended between theoretical and experimental results. These composites were also found to display excellent percentage of heaviness with respect to other conventional materials.

Polyethylene glycol inhibits intestinal neoplasia and induces epithelial apoptosis in Apc(min) mice.

PubMed

Roy, Hemant K; Gulizia, James; DiBaise, John K; Karolski, William J; Ansari, Sajid; Madugula, Madhavi; Hart, John; Bissonnette, Marc; Wali, Ramesh K

2004-11-08

Efficacy of a safe and clinically utilized polyethylene glycol formulation (PEG-3350) to suppress intestinal tumors was investigated in the Apc(min) mouse-model of experimental carcinogenesis. Furthermore, based on our previous finding on the induction of apoptosis in HT-29 cells by PEG, we evaluated its ability to stimulate epithelial cell apoptosis in both Apc(min) mouse as well as AOM-treated rat as a potential molecular mechanism of chemoprevention. Twenty-two Apc(min) mice were randomized equally to PEG or vehicle (control) supplementation. Tumors were scored and uninvolved intestinal mucosal apoptosis was assayed using a modified terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) assay and by immunohistochemical detection of cleaved caspase-3. Supplementation of Apc(min) mice with 10% PEG 3350 (in drinking water) resulted in a 48% (P<0.05) reduction in intestinal tumor burden and induced 2-3 fold increase in mucosal apoptosis. Dietary supplementation of polyethylene glycol (5%) also stimulated colonic mucosal apoptosis 4-5 fold in AOM-treated rats, the regimen that we previously reported to reduce tumor burden by 76% (P<0.05). In summary, we demonstrate, for the first time, that PEG does protect against Apc(min) mouse tumorigenesis. The correlation between pro-apoptotic actions and chemopreventive efficacy of PEG in these models strongly implicates induction of apoptosis as one of the impending mechanisms of chemoprevention.

Stability of an ophthalmic formulation of polyhexamethylene biguanide in gamma-sterilized and ethylene oxide sterilized low density polyethylene multidose eyedroppers

PubMed Central

Wasiak, Mathieu; Jouannet, Mireille; Sautou, Valérie

2018-01-01

Background Polyhexamethylene biguanide (PHMB) eye drops are a frequently used medication to treat Acanthamoeba keratitis. In the absence of marketed PHMB eye drops, pharmacy-compounding units are needed to prepare this much needed treatment, but the lack of validated PHMB stability data severely limits their conservation by imposing short expiration dates after preparation. In this study we aim to assess the physicochemical and microbiological stability of a 0.2 mg/mL PHMB eye drop formulation stored in two kinds of polyethylene bottles at two different temperatures. Methods A liquid chromatography coupled with diode array detector stability-indicating method was validated to quantify PHMB, using a cyanopropyl bonded phase (Agilent Zorbax Eclipse XDB-CN column 4.6 × 75 mm with particle size of 3.5 μm) and isocratic elution consisting of acetonitrile/deionized water (3/97 v/v) at a flow rate of 1.3 mL/min. PHMB eye drops stability was assessed for 90 days of storage at 5 and 25 °C in ethylene oxide sterilized low density polyethylene (EOS-LDPE) and gamma sterilized low density polyethylene (GS-LDPE) bottles. The following analyses were performed: visual inspection, PHMB quantification and breakdown products (BPs) screening, osmolality and pH measurements, and sterility assessment. PHMB quantification and BP screening was also performed on the drops emitted from the multidose eyedroppers to simulate in-use condition. Results The analytical method developed meets all the qualitative and quantitative criteria for validation with an acceptable accuracy and good linearity, and is stability indicating. During 90 days of storage, no significant decrease of PHMB concentration was found compared to initial concentration in all stored PHMB eye drops. However, BP were found at day 30 and at day 90 of monitoring in both kind of bottles, stored at 5 and 25 °C, respectively. Although no significant variation of osmolality was found and sterility was maintained during 90 days of monitoring, a significant decrease of pH in GS-LDPE PHMB eye drops was noticed reaching 4 and 4.6 at 25 °C and 5 °C respectively, compared to initial pH of 6.16. Discussion Although no significant decrease in PHMB concentration was found during 90 days of monitoring in all conditions, the appearance of BPs and their unknown toxicities let us believe that 0.2 mg/mL PHMB solution should be conserved for no longer than 60 days in EOS-LDPE bottles at 25 °C. PMID:29682408

Very large cooperative effects in heterobimetallic titanium-chromium catalysts for ethylene polymerization/copolymerization.

PubMed

Liu, Shaofeng; Motta, Alessandro; Mouat, Aidan R; Delferro, Massimiliano; Marks, Tobin J

2014-07-23

The heterobimetallic complexes, (η(5)-indenyl)[1-Me2Si((t)BuN)TiCl2]-3-CnH2n-[N,N-bis(2-(ethylthio)ethyl)amine]CrCl3 (n = 0, Ti-C0-Cr(SNS); n = 2, Ti-C2-Cr(SNS); n = 6, Ti-C6-Cr(SNS)), (η(5)-indenyl)[1-Me2Si((t)BuN)TiCl2]-3-C2H4-[N,N-bis((o-OMe-C6H4)2P)amine]CrCl3 (Ti-C2-Cr(PNP)), and (η(5)-indenyl)[1-Me2Si((t)BuN)TiCl2]-3-C2H4-[N,N-bis((diethylamine)ethyl)-amine]CrCl3 (Ti-C2-Cr(NNN)), are synthesized, fully characterized, and employed as olefin polymerization catalysts. With ethylene as the feed and MAO as cocatalyst/activator, SNS-based complexes Ti-C0-Cr(SNS), Ti-C2-Cr(SNS), and Ti-C6-Cr(SNS) afford linear low-density polyethylenes (LLDPEs) with exclusive n-butyl branches (6.8-25.8 branches/1000 C), while under identical polymerization conditions Ti-C2-Cr(PNP) and Ti-C2-Cr(NNN) produce polyethylenes with heterogeneous branching (C2, C4, and C≥6) or negligible branching, respectively. Under identical ethylene polymerization conditions, Ti-C0-Cr(SNS) produces polyethylenes with higher activity (4.5× and 6.1×, respectively), Mn (1.3× and 1.8×, respectively), and branch density (1.4× and 3.8×, respectively), than Ti-C2-Cr(SNS) and Ti-C6-Cr(SNS). Versus a CGC(Et)Ti + SNSCr tandem catalyst, Ti-C0-Cr(SNS) yields polyethylene with somewhat lower activity, but with 22.6× higher Mn and 4.0× greater branching density under identical conditions. In ethylene +1-pentene competition experiments, Ti-C0-Cr(SNS) yields 5.5% n-propyl branches and 94.5% n-butyl branches at [1-pentene] = 0.1 M, and the estimated effective local concentration of 1-hexene is ∼8.6 M. In contrast, the tandem CGC(Et)Ti + SNSCr system yields 91.0% n-propyl branches under identical reaction conditions. The homopolymerization and 1-pentene competition results argue that close Ti···Cr spatial proximity together with weak C-H···Ti and C-H···S interactions significantly influence relative 1-hexene enchainment and chain transfer rates, supported by DFT computation, and that such effects are conversion insensitive but cocatalyst and solvent sensitive.

Long-term clinical and radiographic outcome of the PPF system in ceramic-on-polyethylene hip bearings.

PubMed

Legenstein, R; Huber, W; Ungersboeck, A; Boesch, P

2006-01-01

From 1990 to 1991 we implanted 176 non-cemented proximal press-fit (PPF) total hip arthroplasties (THA) with ceramic-on-polyethylene articulation in 170 patients. Of these, 119 patients (122 THA) were followed from 104 to 129 months. Four cups have been revised for aseptic loosening, but revealed no radiolucencies of the stem. Two infections and two dislocations occurred. The median postoperative Harris hip score was 91. Ninety-eight per cent of the patients were satisfied with the outcome, 83% were free of pain and 67% walked without a limp. Serial radiographs showed stable fixation with bone ongrowth in nearly all arthroplasties except for four cups. Stem radiolucencies were first seen within 12 months, but were of no clinical relevance. Proximal periprosthetic bone resorption of the stem was seen in 18%. Radiolucencies occurred because of polyethylene debris-induced granulomas. The PPF system yields satisfactory long-term results in patients with primary and secondary hip osteoarthritis and dysplasia.

Degradation of Green Polyethylene by Pleurotus ostreatus.

PubMed

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Ribeiro, Karla Veloso Gonçalves; Mendes, Igor Rodrigues; Kasuya, Maria Catarina Megumi

2015-01-01

We studied the biodegradation of green polyethylene (GP) by Pleurotus ostreatus. The GP was developed from renewable raw materials to help to reduce the emissions of greenhouse gases. However, little information regarding the biodegradation of GP discarded in the environment is available. P. ostreatus is a lignocellulolytic fungus that has been used in bioremediation processes for agroindustrial residues, pollutants, and recalcitrant compounds. Recently, we showed the potential of this fungus to degrade oxo-biodegradable polyethylene. GP plastic bags were exposed to sunlight for up to 120 days to induce the initial photodegradation of the polymers. After this period, no cracks, pits, or new functional groups in the structure of GP were observed. Fragments of these bags were used as the substrate for the growth of P. ostreatus. After 30 d of incubation, physical and chemical alterations in the structure of GP were observed. We conclude that the exposure of GP to sunlight and its subsequent incubation in the presence of P. ostreatus can decrease the half-life of GP and facilitate the mineralization of these polymers.

Poly(ethylene oxide) surfactant polymers.

PubMed

Vacheethasanee, Katanchalee; Wang, Shuwu; Qiu, Yongxing; Marchant, Roger E

2004-01-01

We report on a series of structurally well-defined surfactant polymers that undergo surface-induced self-assembly on hydrophobic biomaterial surfaces. The surfactant polymers consist of a poly(vinyl amine) backbone with poly(ethylene oxide) and hexanal pendant groups. The poly(vinyl amine) (PVAm) was synthesized by hydrolysis of poly(N-vinyl formamide) following free radical polymerization of N-vinyl formamide. Hexanal and aldehyde-terminated poly(ethylene oxide) (PEO) were simultaneously attached to PVAm via reductive amination. Surfactant polymers with different PEO:hexanal ratios and hydrophilic/hydrophobic balances were prepared, and characterized by FT-IR, 1H-NMR and XPS spectroscopies. Surface active properties at the air/water interface were determined by surface tension measurements. Surface activity at a solid surface/water interface was demonstrated by atomic force microscopy, showing epitaxially molecular alignment for surfactant polymers adsorbed on highly oriented pyrolytic graphite. The surfactant polymers described in this report can be adapted for simple non-covalent surface modification of biomaterials and hydrophobic surfaces to provide highly hydrated interfaces.

Effect of Boron and Phosphate compounds on Thermal and Fire Properties of wood/HDPE composites

Treesearch

Turgay Akbulut; Nadir Ayrilmis; Turker Dundar; Ali Durmus; Robert H. White; Murat Teker

2011-01-01

Melting and non-isothermal crystallization behaviors, oxidative induction time, and fire performance of the injection-molded wood flour-high density polyethylene (HDPE) composites (WPCs) incorporated with different levels (4, 8, or 12 wt %) of boron compounds [borax/boric acid (BX/BA) (0.5:0.5 wt %), zinc borate (ZB)] and phosphorus compounds [mono- and di-ammonium...

Elimination of Aluminum Foil for 81-mm and 120-mm Mortar Ammunition Fiber Container

DTIC Science & Technology

2007-08-01

hard base board. Next, a layer of PolyLam material constructed of 30 lb natural Kraft/14 lb low density polyethylene ( LDPE )/70 lb natural Kraft is...PolyLam material and 30 lb natural Kraft with an exterior layer of 29 lb LDPE laminated to the outside of the tube. The three PolyLam layers are

Characterization of weathered wood-plastic composite surfaces using FTIR spectroscopy, contact angle, and XPS

Treesearch

Nicole M. Stark; Laurent M. Matuana

2007-01-01

Much of the current growth of wood-plastic composites (WPCs) is due to increased penetration into the decking market; therefore it has become imperative to understand the durability of WPCs in outdoor applications. In this study, wood flour filled high-density polyethylene (HDPE) composites were manufactured through either injection molding or extrusion. A set of...

Technical Protocol for Using Soluble Carbohydrates to Enhance Reductive Dechlorination of Chlorinated Aliphatic Hydrocarbons

DTIC Science & Technology

2002-12-19

High -Density Polyethylene HFCS High Fructose Corn Syrup HRC Hydrogen Release Compound HAS Hollow Stem...subsurface injection of a soluble electron donor solution (typically comprised of a carbohydrate such as molasses, whey, high fructose corn syrup (HFCS...whey, high fructose corn syrup (HFCS), glucose, lactate, butyrate, benzoate). Other approaches to enhanced anaerobic bioremediation exist, but

40 CFR 1060.240 - How do I demonstrate that my emission family complies with evaporative emission standards?

Code of Federal Regulations, 2010 CFR

2010-07-01

... of the following control technologies: (1) A coextruded high-density polyethylene fuel tank with a... of 0.40 square meters may use high-permeation gasket material representing a surface area of up to 1...). The carbon must also pass a dust attrition test based on ASTM D3802 (incorporated by reference in...

Influence of a stabilized cap layer on the photodegradation of coextruded high density polyethylene/woodflour composites

Treesearch

Shan Jin; Nicole M. Stark; Laurent M. Matuana

2013-01-01

The effect of light stabilizer’s addition method into wood-plastic composites (WPCs), i.e., surface versus bulk, on their photostability was evaluated. Blends of ultraviolet absorbers (benzotriazole or hydroxyphenyltriazine) with a hindered amine light stabilizer were used as the stabilizing additives. Both unstabilized and photostabilized uncapped (control) samples,...