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1

Investigation on moisture transport through polyester\\/cotton fabrics  

Microsoft Academic Search

The wettability characteristics of different cotton, polyester and multi-layered cotton\\/polyester fabrics have been studied to manage human perspiration well. The vertical capillary action behavior of these fabrics has been compared by measuring the capillary height as a function of time. Wicking coefficients in multi-layered fabrics are found to be much better than in other fabrics of 100% cotton. The yarn

T Sharabaty; F Biguenet; D Dupuis; P Viallier

2

Improvements in the dyeability of polyester fabrics by atmospheric pressure oxygen plasma treatment  

Microsoft Academic Search

Polyester has been widely used as an apparel and technical textile material in the form of fibers, films and plastics due to its excellent mechanical and physical properties. However, its poor surface properties have limited its end?use versatility. In this study, the surface of a polyester fabric was modified by atmospheric pressure plasma treatment with oxygen under different operating conditions

M. M. Kamel; M. M. El Zawahry; H. Helmy; M. A. Eid

2011-01-01

3

Surface modification of polyester fabrics by enzyme treatment  

Microsoft Academic Search

In this study, the effect of enzymatic hydrolysis using lipase and cutinase on poly(ethyleneterephthalate) (PET) fabrics was\\u000a investigated in an attempt to improve the hydrophilicity of these fabrics. The hydrolytic activity of the enzymes was expressed\\u000a for variations in pH levels, temperatures, enzyme concentrations, and treatment times. The effects of using a nonionic surfactant\\u000a were examined by measuring moisture regain

So Hee Lee; Wha Soon Song

2010-01-01

4

Soil removal from polyester fabric by laundering with frequency-modulated ultrasound.  

PubMed

The effectiveness of ultrasound in washing textiles was investigated using polyester woven fabrics soiled with model contaminants such as oleic acid/Sudan III mixture and carbon black. The soiled and original fabrics were washed together in aqueous solutions with shaking or frequency-modulated ultrasound. The detergency and the soil redeposition were evaluated from the change in the surface reflectance of the soiled and the original fabrics due to the washing. The results were strongly dependent on the type of mechanical action. Ultrasound removed the contaminants in a short time and at low bath ratios as compared with shaking. In addition, the ultrasound caused little damage to the fabric during washing. The detergency was much larger for the ultrasonic washing than for shake washing in aqueous solutions containing alkali, surfactants, and commercial detergent. However, uneven cleaning and soil redeposition were frequently observed during ultrasonic washing. This was the only observed limitation to this approach of textile washing. PMID:22531052

Gotoh, Keiko; Hirami, Chisato

2012-01-01

5

Fabrication and integration of planar electrodes for contactless conductivity detection on polyester-toner electrophoresis microchips.  

PubMed

In this report, we describe the microfabrication and integration of planar electrodes for contactless conductivity detection on polyester-toner (PT) electrophoresis microchips using toner masks. Planar electrodes were fabricated by three simple steps: (i) drawing and laser-printing the electrode geometry on polyester films, (ii) sputtering deposition onto substrates, and (iii) removal of toner layer by a lift-off process. The polyester film with anchored electrodes was integrated to PT electrophoresis microchannels by lamination at 120 degrees C in less than 1 min. The electrodes were designed in an antiparallel configuration with 750 microm width and 750 microm gap between them. The best results were recorded with a frequency of 400 kHz and 10 Vpp using a sinusoidal wave. The analytical performance of the proposed microchip was evaluated by electrophoretic separation of potassium, sodium and lithium in 150 microm wide x 6 microm deep microchannels. Under an electric field of 250 V/cm the analytes were successfully separated in less than 90 s with efficiencies ranging from 7000 to 13,000 plates. The detection limits (S/N = 3) found for K+, Na+, and Li+ were 3.1, 4.3, and 7.2 micromol/L, respectively. Besides the low-cost and instrumental simplicity, the integrated PT chip eliminates the problem of manual alignment and gluing of the electrodes, permitting more robustness and better reproducibility, therefore, more suitable for mass production of electrophoresis microchips. PMID:18446805

Coltro, Wendell Karlos Tomazelli; da Silva, José Alberto Fracassi; Carrilho, Emanuel

2008-06-01

6

Study on biodegradability of terephthalic acid in polyester fabric alkali-peeling process wastewater.  

PubMed

Terephthalic acid (TA) and ethylene glycol (EG) are the main pollutants in polyester fabric alkali-peeling process wastewater (PAP-wastewater). The biodegradability of TA is crucial to the deep treatment of PAP-wastewater. Batch and continuous experiments were adopted to study the biodegradation of TA in synthetic wastewater. In anoxic batch experiments TA began to degrade gradually after EG was depleted completely. However, in aerobic batch experiments the biodegradation curves of TA in the presence of EG were almost identical to those of TA in the absence of EG. The combined process of anoxic hydrolysis-acidification bioreactor (HABR) and aerobic hybrid membrane bioreactor (HMBR) was employed to treat synthetic PAP-wastewater in continuous experiments. When TA was fed as sole substrate, about 6.1% was removed in the anoxic HABR and 92.1% was biodegraded in the aerobic HMBR. When TA and EG were fed as substrate, only 1.9% of TA was biodegraded in the anoxic HABR and 96.6% of TA was removed in the aerobic HMBR. By contrast, most EG was removed in the anoxic HABR. The experimental results revealed that the combined process of anoxic HABR and aerobic HMBR was an attractive alternative for the treatment of PAP-wastewater and other similar wastewater. PMID:24473302

Yang, Qiyong; Wu, Zhongwei; Tao, Chunyuan

2014-01-01

7

Ultra-violet protection and water repellency of polyester fabrics treated by surface deposition of nickel under the effect of low temperature plasma  

NASA Astrophysics Data System (ADS)

This paper is aimed at understanding the textile properties of nickel-deposited polyester fabric after treating with low temperature plasma treatment. Low temperature plasma treatment with oxygen gas was employed in this paper to activate a hydrophilic surface for the polyester fabrics and hence facilitate the nickel deposition through an electroless plating process. The textile properties of plasma-induced electroless nickel-plated polyester fabrics were evaluated by different standard testing methods in terms of both physical and chemical performances. The electroless nickel plating with plasma treatment improved significantly the performance of nickel-plated polyester fabrics as reflected by the scanning electron microscopy, tensile strength, ultraviolet protection as well as fabric weight. On the contrary, it also enhanced the fabric thickness and colour fastness to crocking. In addition, there was no influence on the performance of colour fastness to light and colourfastness to laundering. Moreover, the application of plasma treatment adversely affected slightly the performance of contact angle and wrinkle recovery property.

Kan, C. W.; Yuen, C. W. M.

2007-12-01

8

COTTON-POLYESTER FABRIC BLEND ANALYSIS BY NEAR INFRARED (NIR) SPECTROSCOPY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Near Infrared (NIR) techniques have been used extensively to measure key physical and chemical properties of textile materials and textile auxiliaries, including the fiber blending ratio in cotton-polyester (PET) blend fibers and yarns. Interest had grown in the measurement of the fiber blend conte...

9

Mechanical properties and fabrication of small boat using woven glass/sugar palm fibres reinforced unsaturated polyester hybrid composite  

NASA Astrophysics Data System (ADS)

In recent years, sugar palm fibre has been found to have great potential to be used as fibre reinforcement in polymer matrix composites. This research investigates the mechanical properties of woven glass/sugar palm fibres reinforced unsaturated polyester hybrid composite. The composite specimens made of different layer of fibres such as strand mat, natural and hand woven of sugar palm fibres. The composites were fabricated using a compression moulding technique. The tensile and impact test was carried out in accordance to ASTM 5083 and ASTM D256 standard. The fibre glass boat is a familiar material used in boat industry. A lot of research on fabrication process such as lay-up, vacuum infusion mould and resin transfer mould has been conducted. Hybrid material of sugar palm fibre and fibre glass was used in fabricating the boat. This research investigates the method selection for fabrication of small boat application of natural fibre composites. The composite specimens made of different layer of fibres; woven glass fibre, strand mat, natural and hand woven of woven sugar palm fibres were prepared. The small boat were fabricated using a compression moulding and lay up technique. The results of the experiment showed that the tensile strength, tensile modulus, elongation at break value and impact strength were higher than the natural woven sugar palm fibre. The best method for fabricating the small boat was compression moulding technique. As a general conclusion, the usage of glass fibre had improved the tensile properties sugar palm fibre composites and compression moulding technique is suitable to be used in making a small boat application of natural fibre composites.

Misri, S.; Leman, Z.; Sapuan, S. M.; Ishak, M. R.

2010-05-01

10

Application of Nanometal Oxides In Situ in Nonwoven Polyester Fabric for the Removal of Bacterial Indicators of Pollution from Wastewater  

PubMed Central

The objective of this study is to investigate and assess the use of in situ deposit nanosilver (nAg2O) or nanocopper oxides (nCuO) into nonwoven polyester fabric (NWPF) as a safe and effective antibacterial filter of pollution from domestic wastewater. The bactericidal effect of both nAg2O and nCuO was examined against Gram-negative bacteria (Escherichia coli, Salmonella typhi) and Gram-positive bacteria (Enterococcus faecalis, Staphylococcus aureus) using agar diffusion disk method. In addition, the capability of nAg2O and nCuO as disinfectants for secondary treated domestic wastewater was investigated as a case study. Transmission electron microscope (TEM) confirmed the formation of nAg2O and nCuO particles with average particle sizes of 15 and 41 nm, respectively. Disk diffusion results showed that nAg2O had a higher bactericidal effect than nCuO. Moreover, the disinfection of secondary treated wastewater using 1.27?mg/cm3 of nAg2O in the nonwoven fabric was capable of hindering 99.6% and 91.7% of total and fecal coliforms within 10 minutes with a residual value of 18 and 15 MPN-index/100?mL, respectively. The residual total and fecal coliform concentrations were far less than that stated in the national and international limits for wastewater reuse in agriculture purpose. PMID:24672400

Abou-Elela, Sohair I.; Ibrahim, Hanan S.; Kamel, Mohamed M.; Gouda, Mohamed

2014-01-01

11

Evaluation of comfort properties of polyester knitted spacer fabrics finished with water repellent and antimicrobial agents  

Microsoft Academic Search

In order to impart barrier properties against water and microorganisms on breathable three dimensional spacer fabrics as medical\\u000a or technical textiles, fabric samples were treated with two water repellent agents and a quaternary ammonium salt namely cetyltrimethylammonium\\u000a bromide (CTAB), using pad-dry-cure method. Two different water repellent agents based on hydrocarbon and acrylic copolymer\\u000a were used. The water repellent property of

R. Bagherzadeh; M. Montazer; M. Latifi; M. Sheikhzadeh; M. Sattari

2007-01-01

12

Effect of Moisture Management Finish on Comfort Characteristics of Microdenier Polyester Knitted Fabrics  

Microsoft Academic Search

Moisture management can be defined as the controlled movement of water vapor and liquid water (perspiration) from the surface of the skin to the atmosphere through the fabric. Wetting, wicking, and moisture vapor transmission (MVT) properties are the critical aspects for evaluating the comfort performance of textiles. In this study, the effect of stitch length and knit structure on comfort

M. B. Sampath; M. Senthilkumar

2009-01-01

13

Effect of filament fineness on comfort characteristics of moisture management finished polyester knitted fabrics  

Microsoft Academic Search

Clothing comfort is an important aspect for any garment used for sportswear and leisurewear. Every human being sweats during different kinds of activities. An important feature of any fabric is how it transports this water out of the body surface so as to make the wearer feel comfortable. Hence, wetting and wicking properties are critical aspects during wearing of clothes.

MB Sampath; Senthilkumar Mani; G Nalankilli

2011-01-01

14

Development of superhydrophilic and superhydrophobic polyester fabric by growing zinc oxide nanorods.  

PubMed

ZnO nanorods were grown on microfibers of Polyethylene terephthalate (PET) fabric by seeding method to develop hierarchical roughness structure. XRD and XPS analysis show the presence of crystalline ZnO and chemical Zn species at the fiber surface at each stage of the process. Five series of samples with different seed concentrations have been realized, and their surface morphology and topography were characterized by AFM and SEM. Increasing seed concentrations lead to samples with superhydrophilic properties. Not only the water contact angle at fabric surface tends to zero but also the water capillary diffusion inside fabric is faster. Nanostructuration affects the structure inside the fabric, and further experiments with decane liquid have been made to get a better understanding of this effect. To study the superhydrophobicity, nanorods treated samples were modified with octadecyltrimethoxysilane (ODS) by two method; solution deposition and vapor deposition. The superhydrophobicity was characterized by measuring the water contact angle and water sliding angle with 5 ?l water droplet. The samples modified with ODS by vapor deposition showed higher water contact angles and low water sliding angle than the ones modified with solution method. The lotus effect has been well correlated with the surface morphology of the nanorods structured fibers. The application of the Cassie-Baxter equation is discussed. PMID:23261128

Ashraf, Munir; Campagne, Christine; Perwuelz, Anne; Champagne, Philippe; Leriche, Anne; Courtois, Christian

2013-03-15

15

Hydrophilic modification of polyester fabric by applying nanocrystalline cellulose containing surface finish.  

PubMed

In this study, polyethylene terephthalate (PET) fabric was modified by applying a hydrophilic surface finishing agent that contains nanocrystalline cellulose (NCC). To impart superior hydrophilicity, NCC was further cationically modified through quaternization by grafting glycidyl tri-methyl ammonium chloride (GTMAC). A textile binder, PrintRite595(®), was added to the finishing system. The surface finish was applied on the fabric using a rolling-drying-curing process. The modified fabric was characterized in terms of coating durability, moisture regain, and wettability. The durability of the surface finish was tested by six repeated washing steps. The surface properties of the fabric changed from hydrophobic to hydrophilic after heat treatment with the NCC-containing surface finishing agent. The results from the washing fastness, SEM, FTIR, and EDX analyses confirmed that the cationic NCC-containing textile surface finish showed superior adhesion onto the cationic dyeable (anionic) PET surface over the un-modified NCC. Furthermore, the cationic textile surface finish was capable of withstanding multiple washing cycles. PMID:23121945

Zaman, Masuduz; Liu, Hongbin; Xiao, Huning; Chibante, Felipe; Ni, Yonghao

2013-01-16

16

Ink jet printing of bio-treated linen, polyester fabrics and their blend.  

PubMed

Cellulosic fabrics were surface modified using Brewer's yeast filtrate and cellulase enzymes (Valumax A828, Valumax A356) to enhance its affinity to ink jet printing. The effect of enzymes on the surface structure and morphology of the cellulosic fabrics used has been illustrated using scanning electron microscope. Related test as tensile strength have been measured. The bio-treated cellulosic fabrics were digitally printed and the colour strength (K/S) and % increase in K/S were measured. Effect of different conditions (enzyme concentration, temperature and time) was investigated to obtain the optimum condition of each enzyme for each fabric that or which was indicated by higher colour strength. Results show a noticeable increase in the K/S especially for cellulosic linen and its blend compared to the standard samples. The optimum conditions to obtain the higher K/S by using Brewer's yeast filtrate and the other two cellulase enzymes in the pre-treatment of ink jet samples were obtained. PMID:25542129

El-Hennawi, H M; Shahin, A A; Rekaby, M; Ragheb, A A

2015-03-15

17

Polyester non-woven fabric finger cover as a TRUCT Braille reading assistance tool for Braille learners.  

PubMed

Transparent resinous ultraviolet-curing type (TRUCT) Braille signs are becoming more and more popular in Japan, especially when they are printed together with visual characters. These signs are made by screen printing, a technique that can be applied to various base materials, such as paper, metal, and plastic. TRUCT Braille signs have begun to be used in public facilities, such as on tactile maps and on handrails. Naturally, it is expected that Braille beginners will utilize these signs. However, it has been pointed out that the friction between the forefinger and the base material may affect reading accuracy and speed. In this study, we developed a finger cover made of soft, thin polyester non-woven fabric to reduce friction during Braille reading. We also carried out a study to investigate the effect of its use. The subjects were 12 Braille learners with acquired visual impairment, who were asked to read randomly selected characters with and without the finger cover. The results showed that most participants could read TRUCT Braille significantly faster and more accurately with a finger cover than without it, regardless of the base material and dot height. This result suggests that wearing the finger cover enables Braille learners to read TRUCT Braille more efficiently. The finger cover can be used as a Braille reading assistance tool for Braille learners. An additional, health-related advantage of the finger cover is that the forefinger remains clean. We expect that the finger cover will be in practical use in Japan within 1 or 2 years. PMID:17846807

Doi, Kouki; Fujimoto, Hiroshi

2007-11-01

18

Chemical, electrical and electrochemical characterization of hybrid organic/inorganic polypyrrole/PW 12 O 40 3- coating deposited on polyester fabrics  

NASA Astrophysics Data System (ADS)

A study of the stability of conducting fabrics of polyester (PES) coated with polypyrrole/PW12O403- (organic/inorganic hybrid material) in different pH solutions (1, 7, 13) has been done. Washing tests were also done in views of its possible application in electronic textiles such as antistatic clothing. X-ray photoelectron spectroscopy (XPS) studies have been done to quantify the amount of counter ion that remains in the polymer matrix and determine the doping ratio (N+/N) after the different tests. Scanning electron microscopy (SEM) was also used to observe morphological differences after the different tests. Surface resistivity changes were measured by means of electrochemical impedance spectroscopy (EIS). Scanning electrochemical microscopy (SECM) was employed to measure changes in electroactivity after the different tests. Higher pHs caused a decrease of the doping ratio (N+/N), the loss of part of the counter ions and the decrease of its conducting and electrocatalytic properties. The stability in acid media and neutral media and after the washing test was good. Only at pH 13 the loss of the counter ion was widespread and there was a decrease of its conducting and catalytic properties; although the fabrics continued acting mainly as a conducting material.

Molina, J.; Fernández, J.; del Río, A. I.; Bonastre, J.; Cases, F.

2011-09-01

19

Tereunsaturated polyesters  

Microsoft Academic Search

Four tereunsaturated polyesters (TUPs) based on terephthalic acid, maleic anhydride and polyethylene glycol, molecular weight 200 (PEG-200), have been formulated, synthesized and characterised. The effect of variation of styrene monomer and alumina trihydrate (Al2O3·3H2O) filler has been studied on TUP-1 which possesses promising characteristics. Based on these characteristics, TUP-1 (III) with 20% Al2O3·3H2O filler has been selected for inhibition and

J. P. Agrawal; K. S. Kulkarni; D. V. Wast; M. P. Chouk; M. M. Marathe

1992-01-01

20

A new electro-mechanical technique for measurement of stress relaxation of polyester blended fabric with constant torsional strain  

Microsoft Academic Search

Purpose – The purpose of this paper is to analyze the stress-relaxation behavior of different woven fabrics under constant torsional strain in a wrinkled state. For this purpose, a new method for determination of stress-relaxation behavior of the fabric was used while keeping the torsional strain constant. Design\\/methodology\\/approach – In this study, the behavior of stress relaxation of fabric is

Emadaldin Hezavehi; Saeed Shaikhzadeh Najar; P. Zolgharnein; Hamed Yahya

2011-01-01

21

Resisting protein adsorption on biodegradable polyester brushes.  

PubMed

The protein adsorption and degradation behaviors of poly(lactic acid), poly(glycolic acid) (PGA) and poly(?-caprolactone) (PCL) brushes and their co-polymer brushes with oligo(ethylene glycol) (OEG) were studied. Both brush structure and relative amount of OEG and polyester were found to be important to the protein resistance of the brushes. A protein-resisting surface can be fabricated either by using OEG as the top layer of a copolymer brush or by increasing the amount of OEG relative to polyester when using a hydroxyl terminated OEG (OEG-OH) and a methoxy terminated OEG (OEG-OMe) mixture as the substrate layer. The degradation of single polyester brushes and their co-polymer brushes using OEG-OH as a substrate layer or using OEG as a top layer was hindered. This phenomenon was rationalized by the inhibition of the proposed back-biting process as the hydroxy end groups of polyester were blocked by OEG molecules. Among these brushes tested, PGA co-polymer brushes using the methoxy/hydroxyl OEG mixture as the substrate layer proved to be both protein-resistant and degradable due to the relatively large amount of OEG moieties and the good biodegradability of PGA. PMID:24802301

Hu, Xinfang; Gorman, Christopher B

2014-08-01

22

40 CFR 721.9507 - Polyester silane.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Polyester silane. 721.9507 Section 721...Chemical Substances § 721.9507 Polyester silane. (a) Chemical substance...The chemical substance identified as a polyester silane (P-95-1022) is...

2011-07-01

23

21 CFR 177.1590 - Polyester elastomers.  

Code of Federal Regulations, 2011 CFR

...3 2011-04-01 2011-04-01 false Polyester elastomers. 177.1590 Section 177.1590...Repeated Use Food Contact Surfaces § 177.1590 Polyester elastomers. The polyester elastomers identified in paragraph...

2011-04-01

24

Liquid crystal polyester thermosets  

DOEpatents

The present invention provides (1) curable liquid crystalline polyester monomers represented by the formula: R.sup.1 --A.sup.1 --B.sup.1 --A.sup.2 --B.sup.2 --A.sup.3 --R.sup.2 where R.sup.1 and R.sup.2 are radicals selected from the group consisting of maleimide, substituted maleimide, nadimide, substituted naimide, ethynyl, and (C(R.sup.3).sub.2).sub.2 where R.sup.3 is hydrogen with the proviso that the two carbon atoms of (C(R.sup.3).sub.2).sub.2 are bound on the aromatic ring of A.sup.1 or A.sup.3 to adjacent carbon atoms, A.sup.1 and A.sup.3 are 1,4-phenylene and the same where said group contains one or more substituents selected from the group consisting of halo, e.g., fluoro, chloro, bromo, or iodo, nitro lower alkyl, e.g., methyl, ethyl, or propyl, alkoxy, e.g., methoxy, ethoxy, or propoxy, and fluoroalkyl, e.g., trifluoromethyl, pentafluoroethyl and the like, A.sup.2 is selected from the group consisting of 1,4-phenylene, 4,4'-biphenyl, 2,6-naphthylene and the same where said groups contain one or more substituents selected from the group consisting of halo, e.g., fluoro, chloro, bromo, or iodo, nitro, lower alkyl, e.g., methyl, ethyl, and propyl, lower alkoxy, e.g., methoxy, ethoxy, or propoxy, and fluoroalkyl or fluoroalkoxy, e.g., trifluoromethyl, pentafluoroethyl and the like, and B.sup.1 and B.sup.2 are selected from the group consisting of --C(O)--O-- and --O--C(O)--, (2) thermoset liquid crystalline polyester compositions comprised of heat-cured segments derived from monomers represented by the formula: R.sup.1 --A.sup.1 --B.sup.1 --A.sup.2 --B.sup.2 --A.sup.3 --R.sup.2 as described above, (3) curable blends of at least two of the polyester monomers and (4) processes of preparing the curable liquid crystalline polyester monomers.

Benicewicz, Brian C. (Los Alamos, NM); Hoyt, Andrea E. (Los Alamos, NM)

1992-01-01

25

Future of microbial polyesters  

PubMed Central

Numerous microorganisms accumulate polyesters classified as polyhydroxyalkanoates (PHAs) as carbon and energy storage material when the growth condition is unfavorable in the presence of excess carbon source. Natural PHAs typically consist of various (R)-hydroxycarboxylic acids, and exhibit different material properties depending on the monomer composition. Such diversity comes from different metabolic pathways operating in the cell, and thus generating different monomers. Even more diverse PHAs can be produced by metabolically engineered microorganisms, which leads to the biosynthesis of non-natural polyesters containing lactate as a monomer. In order to make PHAs as useful polymers in our daily life, their production cost should be significantly lowered and material properties should be compatible with those produced by petrochemical industries. Metabolic engineering can address these issues by developing microbial strains capable of producing PHAs of desired material properties with high productivity and yield from inexpensive carbon sources. This commentary aims at peeking into the future of PHAs, focusing on the possible metabolic engineering strategies to be taken to achieve these goals. PMID:23714196

2013-01-01

26

Pressure polymerization of polyester  

DOEpatents

A process is disclosed for the preparation of a polyester polymer or polyester copolymer under superatmospheric pressure conditions in a pipe or tubular reaction under turbannular flow conditions. Reaction material having a glycol equivalents to carboxylic acid equivalents mole ratio of from 1.0:1 to 1.2:1, together with a superatmospheric dense gaseous medium are fed co-currently to the reactor. Dicarboxylic acid and/or diol raw materials may be injected into any of the reaction zones in the process during operation to achieve the overall desired mole ratio balance. The process operates at temperatures of from about 220.degree. C. to about 320.degree. C., with turbannular flow achieved before the polymer product and gas exit the reactor process. The pressure in the reaction zones can be in the range from 15 psia to 2500 psia. A polymer product having a DP of a greater than 40, more preferably at least about 70, is achieved by the transfer of water from the reacting material polymer melt to the gaseous medium in the reactor.

Maurer, Charles J. (Matthews, NC); Shaw, Gordon (Charlotte, NC); Smith, Vicky S. (Greer, SC); Buelow, Steven J. (Los Alamos, NM); Tumas, William (Los Alamos, NM); Contreras, Veronica (San Antonio, TX); Martinez, Ronald J. (Santa Cruz, NM)

2000-08-29

27

Invertible architectures from amphiphilic polyesters.  

PubMed

We synthesized and characterized novel amphiphilic polyesters with both hydrophilic and hydrophobic functionalities. The polyesters are soluble in organic and aqueous media and reveal the formation of inverse architectures whose behavior could be correlated to their chemical structure. We foresee that the amphiphilic properties of the polyesters reported here are obviously the basis of new architectures both in solution and on the solid surfaces, which could be used in a broad range of applications. The described synthesis of the copolymers is very simple and is based on commercially available products. That makes this approach attractive in various uses. PMID:16489770

Voronov, Andriy; Kohut, Ananiy; Peukert, Wolfgang; Voronov, Stanislav; Gevus, Orest; Tokarev, Viktor

2006-02-28

28

Polyester based hybrid organic coatings  

NASA Astrophysics Data System (ADS)

Polyesters are a class of polymers widely used in organic coatings applications. In this work, four types of organic coatings based on polyester polyols were prepared: UV-curable polyester/poly(meth)acrylate coatings, thermal curable polyester polyurethane-urea coatings, thermal curable non-isocyanate polyurethane coatings, and UV-curable non-isocyanate polyurethane coatings. Polyester/poly(meth)acrylate block copolymers are synthesized using a combination of polycondensation and Atom-Transfer Radical Polymerization (ATRP). All block copolymers are characterized by means of Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC). In the case of unsaturated-polyester-based block copolymers the main chain double bond in the polyester backbone remains almost unaffected during ATRP. The unsaturated block copolymers are crosslinkable and can form networks upon photo-irradiation in the presence of a suitable photoinitiator. These copolymers might be interesting candidates for coatings with better overall properties than those based on neat polyesters. Thermal curable polyester polyol based Polyurethane-Urea (PUU) coatings were formulated using Partially Blocked HDI isocyanurate (PBH), Isophorone Diamine (IPDA), and polyester polyol. As a comparison, the polyurethane coatings (PU) without adding IPDA were also prepared. The mechanical and viscoelastic properties of the PUU and PU coating were investigated by using tensile test and Dynamic Mechanical Thermal Analyzer (DMTA). It was found that PUU coating exhibited higher crosslink density, Tg, tensile modulus and strength than the corresponding PU coating. Thermal curable non-isocyanate polyurethane coatings were prepared by using polyamine and cyclic carbonate terminated polyester. Cyclic carbonate terminated polyester was synthesized from the reaction of the carbon dioxide and epoxidized polyester which was prepared from the polyester polyol. The properties of the epoxidized and cyclic carbonate terminated polyester were characterized by Brookfield viscometer, NMR and Fourier Transform Infrared spectroscopy (FTIR). UV-curable non-isocyanate polyurethane coatings were formulated by using Acrylated Polyester (APE) oligomer and Non-isocyanate Urethane Dimethacrylates (NUDMA) reactive diluents. The effect of the NUDMA on the viscosity of the APE oligomer was investigated by Brookfield viscometer. The photopolymerization kinetics of NUDMA reactive diluents were investigated by the real time FTIR. It was found that the polymerization conversion and maximum polymerization rate increase with increasing initiator concentration in the range from 0.5 % to 4.0 %. The formulation system containing both the APE oligomer and NUDMA reactive dilutes showed higher polymerization overall conversion and maximum polymerization rate than APE oligomer. After UV curing, the viscoelastic, tensile and thermal properties of the cured films were evaluated as a function of the reactive diluent by using DMTA, tensile test, Differential Scanning Calorimeters (DSC), and Thermal Gravimetric Analysis (TGA). In addition, coating properties such as pencil hardness, chemical resistance, impact resistance, and gloss were also investigated. It was found that crosslink density, storage and tensile modulus, pencil hardness, chemical resistance, gel content, total water absorption, and Tg were directly proportional to amount of the reactive diluents. Compared to the commercial Ethylene Glycol Dimethacrylate (EGDMA) reactive diluent, the NUDMA reactive diluents show significant improvements in impact resistance and elongation at break properties.

Wang, Xiaojiang

29

Polyester ?-assay chip for stem cell studies  

PubMed Central

The application of microfluidic technologies to stem cell research is of great interest to biologists and bioengineers. This is chiefly due to the intricate ability to control the cellular environment, the reduction of reagent volume, experimentation time and cost, and the high-throughput screening capabilities of microscale devices. Despite this importance, a simple-to-use microfluidic platform for studying the effects of growth factors on stem cell differentiation has not yet emerged. With this consideration, we have designed and characterized a microfluidic device that is easy to fabricate and operate, yet contains several functional elements. Our device is a simple polyester-based microfluidic chip capable of simultaneously screening multiple independent stem cell culture conditions. Generated by laser ablation and stacking of multiple layers of polyester film, this device integrates a 10?×?10 microwell array for cell culture with a continuous perfusion system and a non-linear concentration gradient generator. We performed numerical calculations to predict the gradient formation and calculate the shear stress acting on the cells inside the device. The device operation was validated by culturing murine embryonic stem cells inside the microwells for 5 days. Furthermore, we showed the ability to maintain the pluripotency of stem cell aggregates in response to concentrations of leukemia inhibitory factor ranging from 0 to ?1000 U/ml. Given its simplicity, fast manufacturing method, scalability, and the cell-compatible nature of the device, it may be a useful platform for long-term stem cell culture and studies. PMID:24278097

Piraino, Francesco; Selimovi?, Šeila; Adamo, Marco; Pero, Alessandro; Manoucheri, Sam; Bok Kim, Sang; Demarchi, Danilo; Khademhosseini, Ali

2012-01-01

30

Fabric Facts.  

E-print Network

by the general name-for example, Dacron polyester. Trade names also may indicate a certain type of yarn processing. Several fibers or finishes may be combined under one trade name. Refer to Extension publication B-1240 Guidelines tor Quality Clothing... fabric. Reduces drape. Significantly reduces strength. Non- to semi-durable, 6 especially when laundered with soap or chlorine bleach. Primary Use Lingerie, sleepwear Shoes and socks Luggage Underwear Cotton, rayon and linen Children...

Saunders, Becky

1980-01-01

31

Which polyesters can mimic polyethylene?  

PubMed

Self-metathesis of erucic acid by [(PCy(3))(?-C-C(3)H(4)N(2)Mes(2))Cl(2)Ru = CHPh] (Grubbs second- generation catalyst) followed by catalytic hydrogenation and purification via the ester yields 1,26-hexacosanedioate (>99% purity). Polyesterification with 1,26-hexacosanediol, generated from the diester, affords polyester-26,26, which features a T(m) of 114 °C (T(c) = 92 °C, ?H(m) = 160 J g(-1)). Ultralong-chain model polyesters-38,23 (T(m) = 109 °C) and -44,23 (T(m) = 111 °C), generated via multistep procedures including acyclic diene metathesis polymerization, underline that melting points of such aliphatic polyesters do not gradually increase with methylene sequence chain length. Available data suggest that to mimic linear polyethylenes thermal properties, even longer sequences, amounting to at least four times a fatty acid chain, fully incorporated in a linear fashion are required. PMID:23161497

Stempfle, Florian; Ortmann, Patrick; Mecking, Stefan

2013-01-11

32

Energy performance of fabric roofs  

Microsoft Academic Search

The energy efficiency of fabric roofs is dependent on the thermal and optical characteristics of the fabric envelope. Vinyl coated polyester is used in temporary inflated ''bubbles''. Teflon coated fiberglass has been used in permanent structures such as the Pontiac Silverdome. Daylighting through the fabric is ample, but heat loss can be high in cold climates. The roof performs better

Beitin

1982-01-01

33

Fabrication  

NASA Technical Reports Server (NTRS)

What aspects of optical fabrication technology need to be developed so as to facilitate existing planned missions, or enable new ones? Throughout the submillimeter to UV wavelengths, the common goal is to push technology to the limits to make the largest possible apertures that are diffraction limited. At any one wavelength, the accuracy of the surface must be better than lambda/30 (rms error). The wavelength range is huge, covering four orders of magnitude from 1 mm to 100 nm. At the longer wavelengths, diffraction limited surfaces can be shaped with relatively crude techniques. The challenge in their fabrication is to make as large as possible a reflector, given the weight and volume constraints of the launch vehicle. The limited cargo diameter of the shuttle has led in the past to emphasis on deployable or erectable concepts such as the Large Deployable Reflector (LDR), which was studied by NASA for a submillimeter astrophysics mission. Replication techniques that can be used to produce light, low-cost reflecting panels are of great interest for this class of mission. At shorter wavelengths, in the optical and ultraviolet, optical fabrication will tax to the limit the most refined polishing methods. Methods of mechanical and thermal stabilization of the substrate will be severely stressed. In the thermal infrared, the need for large aperture is tempered by the even stronger need to control the telescope's thermal emission by cooled or cryogenic operation. Thus, the SIRTF mirror at 1 meter is not large and does not require unusually high accuracy, but the fabrication process must produce a mirror that is the right shape at a temperature of 4 K. Future large cooled mirrors will present more severe problems, especially if they must also be accurate enough to work at optical wavelengths. At the very shortest wavelengths accessible to reflecting optics, in the x-ray domain, the very low count fluxes of high energy photons place a premium on the collecting area. It is not necessary to reach or even approach the diffraction limit, which would demand subnanometer fabrication and figure control. Replication techniques that produce large very lightweight surfaces are of interest for x-ray optics just as they are for the submillimeter region. Optical fabrication requirements are examined in more detail for missions in each of the three spectral regions of interest in astrophysics.

Angel, Roger; Helms, Richard; Bilbro, Jim; Brown, Norman; Eng, Sverre; Hinman, Steve; Hull-Allen, Greg; Jacobs, Stephen; Keim, Robert; Ulmer, Melville

1992-01-01

34

Synthesis, characterization and mechanical properties of polyester-based aliphatic polyurethane elastomers containing hyperbranched polyester segments  

Microsoft Academic Search

Aliphatic polyester-based polyurethane (PU) elastomers with hyperbranched polyester segments were synthesized from polyester diol, hydroxyl-terminated hyperbranched polyester (HB-20), isophorone diisocyanate (PDI) and 1,4-butanediol. The crosslinking density of the PU elastomer was calculated by using Flory–Rehner equation. The degree of hydrogen bonding, the microstructure and the morphologies of these PU materials were characterized by means of FT-IR, WAXD and DSC, respectively.

Jie Zhang; Chun Pu Hu

2008-01-01

35

40 CFR 721.8082 - Polyester polyurethane acrylate.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Polyester polyurethane acrylate. 721.8082 Section 721...Substances § 721.8082 Polyester polyurethane acrylate. (a) Chemical substance...identified generically as polyester polyurethane acrylate (PMN P-93-498)...

2013-07-01

36

40 CFR 721.8082 - Polyester polyurethane acrylate.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Polyester polyurethane acrylate. 721.8082 Section 721...Substances § 721.8082 Polyester polyurethane acrylate. (a) Chemical substance...identified generically as polyester polyurethane acrylate (PMN P-93-498)...

2012-07-01

37

40 CFR 721.8082 - Polyester polyurethane acrylate.  

Code of Federal Regulations, 2014 CFR

... 2014-07-01 false Polyester polyurethane acrylate. 721.8082 Section 721...Substances § 721.8082 Polyester polyurethane acrylate. (a) Chemical substance...identified generically as polyester polyurethane acrylate (PMN P-93-498)...

2014-07-01

38

40 CFR 721.8082 - Polyester polyurethane acrylate.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Polyester polyurethane acrylate. 721.8082...Chemical Substances § 721.8082 Polyester polyurethane acrylate. (a) Chemical...chemical substance identified generically as polyester polyurethane acrylate (PMN...

2011-07-01

39

40 CFR 721.10213 - Polyether polyester copolymer phosphate (generic).  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Polyether polyester copolymer phosphate (generic). 721...Substances § 721.10213 Polyether polyester copolymer phosphate (generic). ...substance identified generically as polyether polyester copolymer phosphate (PMN...

2011-07-01

40

Biodegradability and Biodegradation of Polyesters  

Microsoft Academic Search

A variety of biodegradable plastics have been developed in order to obtain useful materials that do not cause harm to the\\u000a environment. Among the biodegradable plastics, aliphatic polyesters such as: poly(3-hydroxybutyrate) (PHB), poly(?-caprolactone)\\u000a (PCL), poly(butylene succinate) (PBS), and poly(l-lactide) (PLA) have become the focus of interest because of their inherent biodegradability. However, before their widespread\\u000a applications, comprehensive studies on the

Yutaka Tokiwa; Buenaventurada P. Calabia

2007-01-01

41

Psychophysical determination of moisture perception in high-performance shirt fabrics in relationtosweating level  

Microsoft Academic Search

Perceived moisture in shirt fabrics was determined using psychophysical methods and objectively measured moisture absorption behaviours. Four shirt fabrics were assessed: cotton; regular polyester; high-performance polyester; ahigh-performance polyester\\/polypropylene blend. After a screening test, six of 10 female subjects participated inthe determination of difference thresholds (DLs) for moisture perception. Low and high amounts of sweat were simulated using 0.5 and 1.5 ml

Eunkyung Jeon; Shinjung Yoo; Eunae Kim

2011-01-01

42

Flame retardant antibacterial cotton high-loft nonwoven fabrics  

Technology Transfer Automated Retrieval System (TEKTRAN)

Flame retardant treated gray cotton fibers were blended with antibacterial treated gray cotton fibers and polyester/polyester sheath/core bicomponent fibers to form high-loft fabrics. The high flame retardancy (FR) and antibacterial property of these high lofts were evaluated by limiting oxygen inde...

43

A study on thermophysiological comfort properties of fabrics in relation to constituent fibre fineness and cross-sectional shapes  

Microsoft Academic Search

The present study reports the effect of linear densities and profiles of polyester fibres on the physiological properties of their fabrics. Four different polyester fibre finenesses along with microdenier and four cross-sectional shapes (circular, scalloped oval, tetrakelion and trilobal) were selected to produce two sets of 2\\/1 twill fabrics; one composed of 100% polyester and the other 67:33 P\\/V blends.

R. K. Varshney; V. K. Kothari; S. Dhamija

2010-01-01

44

21 CFR 177.1590 - Polyester elastomers.  

Code of Federal Regulations, 2013 CFR

...purpose of this section, polyester elastomers are those produced by the ester exchange reaction when one or more of the following phthalates—dimethyl terephthalate, dimethyl orthophthalate, and dimethyl isophthalate—is made to react with...

2013-04-01

45

21 CFR 177.1590 - Polyester elastomers.  

Code of Federal Regulations, 2014 CFR

...purpose of this section, polyester elastomers are those produced by the ester exchange reaction when one or more of the following phthalates—dimethyl terephthalate, dimethyl orthophthalate, and dimethyl isophthalate—is made to react with...

2014-04-01

46

21 CFR 177.1590 - Polyester elastomers.  

Code of Federal Regulations, 2012 CFR

...purpose of this section, polyester elastomers are those produced by the ester exchange reaction when one or more of the following phthalates—dimethyl terephthalate, dimethyl orthophthalate, and dimethyl isophthalate—is made to react with...

2012-04-01

47

Self-cleaning Polyurethane and Polyester Coatings.  

E-print Network

??Self-cleaning titanium dioxide (TiO2) based polyurethane and polyester nanocomposites were synthesized, characterized and tested in this thesis. A monomer functionalization method (“grafting from” polymerization) was… (more)

Tang, Yixing

2013-01-01

48

Integrated analysis of low profile unsaturated polyester and vinylester resins cured at low temperatures  

NASA Astrophysics Data System (ADS)

Unsaturated polyester and vinylester resins are used in a wide variety of applications. These materials provide high structural stability, increased resistance to solvent and temperature, and improved mechanical stability. Low profile additives have been found highly effective in eliminating the polymerization shrinkage of unsaturated polyester resins in high temperature molding processes such as compression molding of SMC and injection molding of BMC. In recent years, the improvement focuses on the development of low temperature and low-pressure fabrication techniques, such as low temperature/low pressure SMC, RTM, SCRIMP, to significantly reduce the tooling cost. However, poor performance of low profile additives and high residual reactivity in low temperature molding processes unavoidably undermine further applications of unsaturated polyester and vinylester resins. Therefore, there is considerable potential for improving the process through greater technical understanding of reaction and volume shrinkage control mechanism in low temperature cure of unsaturated polyester and vinylester resins. An integrated analysis is carried out in this study to investigate the reaction kinetics and shrinkage control of unsaturated polyester or vinylester resins with low profile additives cured at low temperatures. A differential scanning calorimeter (DSC), a Fourier transform infrared spectrometer (FTIR), and a rheometrics dynamic analyzer (RDA) are used to study the reaction kinetics and rheological behaviors. A dilatometer is applied to study the volume change. A scanning electron microscopy (SEM) and an optical microscopy are employed to investigate the structure and morphology evolution during curing. The effects of curing agents including initiator, promoter, and comonomer on the low temperature polymerization are investigated. These experiments are designed to provide information regarding the polymerization mechanism and microstructure evolution throughout the free radical polymerization. In addition, this information along with the relation between morphology and properties of crosslinked polymeric materials will be used to optimize polymerization conditions of unsaturated polyester and vinylester resins with desired properties for applications in composite matrix.

Cao, Xia

49

One-pot preparation of unsaturated polyester nanocomposites containing functionalized graphene sheets via a novel solvent-exchange method  

Technology Transfer Automated Retrieval System (TEKTRAN)

This paper reports a convenient one-pot method integrating a novel solvent-exchange method into in situ melt polycondensation to fabricate unsaturated polyester nanocomposites containing functionalized graphene sheets (FGS). A novel solvent-exchange method was first developed to prepare graphene oxi...

50

Microbial production of lactate-containing polyesters  

PubMed Central

Due to our increasing concerns on environmental problems and limited fossil resources, biobased production of chemicals and materials through biorefinery has been attracting much attention. Optimization of the metabolic performance of microorganisms, the key biocatalysts for the efficient production of the desired target bioproducts, has been achieved by metabolic engineering. Metabolic engineering allowed more efficient production of polyhydroxyalkanoates, a family of microbial polyesters. More recently, non-natural polyesters containing lactate as a monomer have also been produced by one-step fermentation of engineered bacteria. Systems metabolic engineering integrating traditional metabolic engineering with systems biology, synthetic biology, protein/enzyme engineering through directed evolution and structural design, and evolutionary engineering, enabled microorganisms to efficiently produce natural and non-natural products. Here, we review the strategies for the metabolic engineering of microorganisms for the in vivo biosynthesis of lactate-containing polyesters and for the optimization of whole cell metabolism to efficiently produce lactate-containing polyesters. Also, major problems to be solved to further enhance the production of lactate-containing polyesters are discussed. PMID:23718266

Yang, Jung Eun; Choi, So Young; Shin, Jae Ho; Park, Si Jae; Lee, Sang Yup

2013-01-01

51

Microbial odor profile of polyester and cotton clothes after a fitness session.  

PubMed

Clothing textiles protect our human body against external factors. These textiles are not sterile and can harbor high bacterial counts as sweat and bacteria are transmitted from the skin. We investigated the microbial growth and odor development in cotton and synthetic clothing fabrics. T-shirts were collected from 26 healthy individuals after an intensive bicycle spinning session and incubated for 28 h before analysis. A trained odor panel determined significant differences between polyester versus cotton fabrics for the hedonic value, the intensity, and five qualitative odor characteristics. The polyester T-shirts smelled significantly less pleasant and more intense, compared to the cotton T-shirts. A dissimilar bacterial growth was found in cotton versus synthetic clothing textiles. Micrococci were isolated in almost all synthetic shirts and were detected almost solely on synthetic shirts by means of denaturing gradient gel electrophoresis fingerprinting. A selective enrichment of micrococci in an in vitro growth experiment confirmed the presence of these species on polyester. Staphylococci were abundant on both cotton and synthetic fabrics. Corynebacteria were not enriched on any textile type. This research found that the composition of clothing fibers promotes differential growth of textile microbes and, as such, determines possible malodor generation. PMID:25128346

Callewaert, Chris; De Maeseneire, Evelyn; Kerckhof, Frederiek-Maarten; Verliefde, Arne; Van de Wiele, Tom; Boon, Nico

2014-11-01

52

49 CFR 173.165 - Polyester resin kits.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Polyester resin kits. 173.165 Section...Class 1 and Class 7 § 173.165 Polyester resin kits. (a) Except for transportation by aircraft, polyester resin kits consisting of a base...

2011-10-01

53

40 CFR 721.6485 - Hydroxy terminated polyester.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Hydroxy terminated polyester. 721.6485 Section 721.6485...Substances § 721.6485 Hydroxy terminated polyester. (a) Chemical substance and significant...identified generically as a hydroxy terminated polyester (PMN P-95-1213) is subject...

2011-07-01

54

(Citric acid–co–polycaprolactone triol) polyester  

PubMed Central

Tissue engineering holds enormous challenges for materials science, wherein the ideal scaffold to be used is expected to be biocompatible, biodegradable and possess mechanical and physical properties that are suitable for target application. In this context, we have prepared degradable polyesters in different ratios by a simple polycondensation technique with citric acid and polycaprolactone triol. Differential scanning calorimetry indicated that the materials were amorphous based the absence of a crystalline melting peak and the presence of a glass transition temperature below 37°C. These polyesters were found to be hydrophilic and could be tailor-made into tubes and films. Porosity could also be introduced by addition of porogens. All the materials were non-cytotoxic in an in vitro cytotoxicity assay and may degrade via hydrolysis to non-toxic degradation products. These polyesters have potential implications in the field of soft tissue engineering on account of their similarity of properties. PMID:23507730

Thomas, Lynda V.; Nair, Prabha D.

2011-01-01

55

Engineering bacteria to manufacture functionalized polyester beads.  

PubMed

The ability to generate tailor-made, functionalized polyester (polyhydroxyalkanoate, PHA) beads in bacteria by harnessing their natural carbon-storage granule production system is an exciting recent development. Proteins that naturally attach to the polyester granule core were rationally engineered to enable in vivo production of PHA beads which are applicable in bioseparation, protein purification, enzyme immobilization and diagnostics and which show advantageous properties toward the development of safe and efficient particulate vaccines. These beads are recombinantly produced as fully functional, insoluble polyester inclusions that can be easily separated from the cell. This simple one-step production of functionalized beads provides a tantalizing alternative to current commercial functional beads, for which proteins must be expressed, purified and then chemically attached to solid supports. The recent success in generating antigen-displaying PHA granules in the food-grade bacterium Lactococcus lactis capable of mediating protective immunity against Mycobacterium tuberculosis infection highlights the promise and flexibility of this new technology. PMID:22705844

Draper, Jenny L; Rehm, Bernd H

2012-01-01

56

Engineering bacteria to manufacture functionalized polyester beads  

PubMed Central

The ability to generate tailor-made, functionalized polyester (polyhydroxyalkanoate, PHA) beads in bacteria by harnessing their natural carbon-storage granule production system is an exciting recent development. Proteins that naturally attach to the polyester granule core were rationally engineered to enable in vivo production of PHA beads which are applicable in bioseparation, protein purification, enzyme immobilization and diagnostics and which show advantageous properties toward the development of safe and efficient particulate vaccines. These beads are recombinantly produced as fully functional, insoluble polyester inclusions that can be easily separated from the cell. This simple one-step production of functionalized beads provides a tantalizing alternative to current commercial functional beads, for which proteins must be expressed, purified and then chemically attached to solid supports. The recent success in generating antigen-displaying PHA granules in the food-grade bacterium Lactococcus lactis capable of mediating protective immunity against Mycobacterium tuberculosis infection highlights the promise and flexibility of this new technology. PMID:22705844

Draper, Jenny L.; Rehm, Bernd H.

2012-01-01

57

Influence of surface treatment on the electroless nickel plating of textile fabric  

NASA Astrophysics Data System (ADS)

The present study is performed with an objective to acquire a deeper understanding of the properties of nickel-plated polyester fabric after conducing low temperature plasma treatment. Low temperature plasma treatment with oxygen and argon gases was employed to render a hydrophilic property of woven polyester fabrics and facilitate the absorption of a palladium catalyst in order to provide a catalytic surface for electroless nickel plating. The properties of plasma-induced electroless nickel-plated polyester fabrics were evaluated by various standard testing methods in terms of both physical and chemical performances.

Yuen, C. W. M.; Jiang, S. Q.; Kan, C. W.; Tung, W. S.

2007-04-01

58

Thermal and physical characterization of glycerol polyesters  

Technology Transfer Automated Retrieval System (TEKTRAN)

Glycerol polyesters were prepared by the condensation of glycerol and adipic acid, azelaic acid, sebacic acid, or suberic acids. After 48 hours at 125 deg C the polymers were clear and flexible. Samples of the reaction mixtures were analyzed by modulated differential scanning calorimetry to identi...

59

Physical and mechanical degradation of shirting fabrics in burial conditions.  

PubMed

The current focal areas within forensic textile science are fibre identification and assessment of the method of damage to fabrics. This paper investigates fabric degradation within clandestine burials. The fabrics considered in this paper, unlike previous archaeological studies, are a modern polyester-cotton blend (65%/35%) and a 100% cotton fabric both of which are commonly used for men's shirting fabrics in the UK. Three laundering conditions were investigated (i) not-laundered, (ii) laundered 6 times, and (iii) laundered 60 times; this represented varying conditions of fabric upon clothing deposition. The two burial conditions; sand and clay, were selected as extremes of soil type. The deposition times (15 and 30 days) were based on a study of clandestine burials in UK crimes. There were clear differences in how polyester-cotton and cotton stained within the two different soil conditions, polyester-cotton becoming extensively stained after a 30-day deposition in sand. The tear force required to tear the fabric after deposition, suggested that polyester/cotton fabrics were consistently weaker after burial, regardless of soil type and deposition period. There was also significant damage caused to not-laundered cotton fabrics after a 30-day deposition in clay. This work indicates that common apparel fabrics can degrade in relatively short times when buried. PMID:22677503

Mitchell, J L; Carr, D J; Niven, B E; Harrison, K; Girvan, E

2012-10-10

60

Electromagnetic interference shielding effectiveness of electroless Cu-plated PET fabrics  

Microsoft Academic Search

In order to develop the high quality electromagnetic interference (EMI) shielding textiles for protective clothing, polyester fabrics were electroless copper-plated. Effects of pretreatment conditions such as scouring, etching, and catalyzation on electromagnetic interference shielding effectiveness (EMISE) and physical properties of treated fabrics were investigated.High EMISE of fabrics over the wide range of frequency level were obtained when fabrics were scoured

Eun Gyeong Han; Eun Ae Kim; Kyung Wha Oh

2001-01-01

61

An experimental investigation of nonwoven filter cloth with and without reinforcement of woven fabric  

Microsoft Academic Search

In this experimental study, the effect of needling intensity and reinforcement fabric on some physical properties of needle?punched nonwoven filters was investigated. The needle?punched nonwoven filters with different needling intensities were fabricated with and without reinforcement fabrics. Recycled polyester fibers were chosen as raw materials, and acrylic fibers were used in the reinforcement fabrics. The variation of physical properties of

M. E. Yuksekkaya; M. Tercan; G. Dogan

2010-01-01

62

Role of Biotechnology in the Treatment of Polyester Fabric  

Microsoft Academic Search

Poly (ethylene terephthalate) fibre [PET] is the commonly used fibre for majority of end-use applications, however, the desire\\u000a for improved textile properties such as wettability or hydrophilicity are increasing. Biotechnology can be defined as the\\u000a application of scientific and engineering to the processing of materials by biological agents to provide goods and services.\\u000a The environmental issues associated with the textile

S. D. Wavhal; R. H. Balasubramanya

2011-01-01

63

Polyester-grafted cellulose nanowhiskers: a new approach for tuning the microstructure of immiscible polyester blends.  

PubMed

Cellulose nanowhiskers (CNW), extracted from ramie fibers by sulfuric acid hydrolysis, were used as substrates to compatibilize binary polyester blends containing 50/50 (w/w) polycaprolactone (PCL) and polylactide (PLA). To tailor their interfacial energy and fine-tune their adhesion with the components of the blend, CNW were subjected to different surface polyester grafting by the means of ring-opening polymerization. PCL and PLA homopolyesters as well as P(CL-b-LA) diblock copolymers were successfully grafted on the surface of CNW and the resulting substrates were loaded into the PCL/PLA blend by melt-blending. Morphological and rheological analyses were conducted in order to evaluate the ability of these nanoparticles to enhance the compatibility of PCL/PLA blends. Our results showed that unmodified CNW as well as (co)polyester-grafted CNW improved, at different levels, the compatibility of PCL/PLA blends by preventing from coalescence the dispersed domains. (co)polyester-grafted CNW also enhance the mechanical properties of the blend, which can be explained by the formation of cocontinuous phase morphology at the interface. Our findings suggest that (co)polyester-grafted CNW, especially CNW-g-P(CL-b-LA) diblock copolymers, can serve as a suitable nanofiller to tune the compatibility of PCL/PLA blends and their related microstructures. PMID:22738142

Goffin, Anne-Lise; Habibi, Youssef; Raquez, Jean-Marie; Dubois, Philippe

2012-07-25

64

40 CFR 721.10298 - MDI terminated polyester polyurethane polymer (generic).  

Code of Federal Regulations, 2012 CFR

... false MDI terminated polyester polyurethane polymer (generic). 721.10298...10298 MDI terminated polyester polyurethane polymer (generic). (a) Chemical...generically as MDI terminated polyester polyurethane polymer (P-11-662) is...

2012-07-01

65

40 CFR 721.10298 - MDI terminated polyester polyurethane polymer (generic).  

Code of Federal Regulations, 2014 CFR

... false MDI terminated polyester polyurethane polymer (generic). 721.10298...10298 MDI terminated polyester polyurethane polymer (generic). (a) Chemical...generically as MDI terminated polyester polyurethane polymer (P-11-662) is...

2014-07-01

66

40 CFR 721.10298 - MDI terminated polyester polyurethane polymer (generic).  

Code of Federal Regulations, 2013 CFR

... false MDI terminated polyester polyurethane polymer (generic). 721.10298...10298 MDI terminated polyester polyurethane polymer (generic). (a) Chemical...generically as MDI terminated polyester polyurethane polymer (P-11-662) is...

2013-07-01

67

21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.  

Code of Federal Regulations, 2011 CFR

...false Partial phosphoric acid esters of polyester resins. 175.260 Section 175.260...260 Partial phosphoric acid esters of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section...

2011-04-01

68

High performance polyester concrete using recycled PET  

SciTech Connect

Recycled polyethylene terephthalate (PET) plastic wastes could be used in production of unsaturated polyester resins. In turn, these resins could be mixed with inorganic aggregates to produce polymer concrete (PC). Unsaturated polyesters based on recycled PET might be a potentially lower source cost of resins for producing useful PC based-products. The advantage of recycling PET in PC is that the PET materials do not have to be purified, including removal of colors, to the same extent as other PET recycling applications, which should facilitate the recycling operation and minimize its cost. The recycling of PET in PC could also help save energy and allow the long term disposal of the PET waste, an important advantage in recycling applications.

Rebeiz, K.S. [Lafayette Coll., Easton, PA (United States). Dept. of Civil and Environmental Engineering

1995-10-01

69

New intramolecular effect observed for polyesters: An anomeric effect  

Microsoft Academic Search

A series of polyesters was prepared to evaluate hydrolytic stability as a function of cyclohexyl dibasic acid content. The\\u000a three cyclohexyl dibasic acids: 1,2; 1,3; and 1,4 were formulated into polyesters with two glycols. The proportion of cis\\u000a and trans isomers was evaluated via 1H NMR. The hydrolytic stability of short chain polyesters was evaluated in an acetone\\/water mixture which

Mark D. Soucek; Aaron H. Johnson

2004-01-01

70

Isolation and characterization of sucrose polyesters  

Microsoft Academic Search

Various chromatographic techniques for isolation and separation of highly esterified sucrose polyesters (SPE) of olive oil\\u000a are described. High-performance size-exclusion chromatography was used to check the purity of the samples, particularly to\\u000a show that SPE were free from unreacted fatty acid methyl esters. Thin-layer chromatography (TLC), Iatroscan TLC flame-ionization\\u000a detection (FID) and highperformance liquid chromatography (HPLC) on reversed-phase were applied

J. J. Rios; M. C. Pérez-Camino; G. Márquez-Ruiz; M. C. Dobarganes

1994-01-01

71

Unsaturated polyester nanocomposites filled with nano alumina  

Microsoft Academic Search

Alumina nanoparticles (60–70 nm) were prepared by the sol–gel technique using citric acid and aluminum nitrate. Casting technique\\u000a was used to make nanocomposites of unsaturated polyester (UPR) and nano alumina. Transmission Electron Microscopy (TEM) study\\u000a demonstrated that nano alumina particles were dispersed uniformly in the UPR matrix and agglomeration of particles was found\\u000a at higher filler loading (>5 wt%). The nanocomposites show

R. Baskaran; M. Sarojadevi; C. T. Vijayakumar

2011-01-01

72

Curing of Unsaturated Polyester: Network Formation  

NASA Astrophysics Data System (ADS)

Unsaturated polyester resins in styrene as comonomer solvent gels to a thermoset stageby network formation due to free radicals produced by the redox reaction between cobalt octoate (promoter) and methyl ethyl ketone peroxide (MEKP) as initiator. Gel times can be reduced or enhanced by the use of N,N-Dimethyl aniline (DMA) or pyridine respectively. The technique of hand lay-up for producing glass reinforced fiber (GRF) is described.

Toorkey, R. F.; Rajanna, K. C.; Sai Prakash, P. K.

1996-04-01

73

Biodegradation of microbial and synthetic polyesters by fungi.  

PubMed

A variety of biodegradable polyesters have been developed in order to obtain useful biomaterials and to reduce the impact of environmental pollution caused by the large-scale accumulation of non-degradable waste plastics. Polyhydroxyalkanoates, poly(epsilon-caprolactone), poly( l-lactide), and both aliphatic and aromatic polyalkylene dicarboxylic acids are examples of biodegradable polyesters. In general, most aliphatic polyesters are readily mineralized by a number of aerobic and anaerobic microorganisms that are widely distributed in nature. However, aromatic polyesters are more resistant to microbial attack than aliphatic polyesters. The fungal biomass in soils generally exceeds the bacterial biomass and thus it is likely that fungi may play a considerable role in degrading polyesters, just as they predominantly perform the decomposition of organic matter in the soil ecosystem. However, in contrast to bacterial polyester degradation, which has been extensively investigated, the microbiological and environmental aspects of fungal degradation of polyesters are unclear. This review reports recent advances in our knowledge of the fungal degradation of microbial and synthetic polyesters and discusses the ecological importance and contribution of fungi in the biological recycling of waste polymeric materials in the biosphere. PMID:12743758

Kim, D Y; Rhee, Y H

2003-05-01

74

Degradation rates of glycerol polyesters at acidic and basic conditions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Polyesters prepared from glycerol with mixtures of adipic and citric acids were evaluated in the laboratory to estimate degradation rates over a range of pH conditions. These renewable polymers provide a market for glycerol that is generated during biodiesel production. The polyesters were prepared...

75

Disposable polyester-toner electrophoresis microchips for DNA analysis.  

PubMed

Microchip electrophoresis has become a powerful tool for DNA separation, offering all of the advantages typically associated with miniaturized techniques: high speed, high resolution, ease of automation, and great versatility for both routine and research applications. Various substrate materials have been used to produce microchips for DNA separations, including conventional (glass, silicon, and quartz) and alternative (polymers) platforms. In this study, we perform DNA separation in a simple and low-cost polyester-toner (PeT)-based electrophoresis microchip. PeT devices were fabricated by a direct-printing process using a 600 dpi-resolution laser printer. DNA separations were performed on PeT chip with channels filled with polymer solutions (0.5% m/v hydroxyethylcellulose or hydroxypropylcellulose) at electric fields ranging from 100 to 300 V cm(-1). Separation of DNA fragments between 100 and 1000 bp, with good correlation of the size of DNA fragments and mobility, was achieved in this system. Although the mobility increased with increasing electric field, separations showed the same profile regardless of the electric field. The system provided good separation efficiency (215,000 plates per m for the 500 bp fragment) and the separation was completed in 4 min for 1000 bp fragment ladder. The cost of a given chip is approximately $0.15 and it takes less than 10 minutes to prepare a single device. PMID:22545263

Duarte, Gabriela R M; Coltro, Wendell K T; Borba, Juliane C; Price, Carol W; Landers, James P; Carrilho, Emanuel

2012-06-01

76

Polyester Based On Biodiesel Industry Residues  

NASA Astrophysics Data System (ADS)

Biodiesel production is growing exponentially offering the energy network an alternative fuel from renewable sources. However, large quantities of crude glycerol are generated as a bi-product (10-30%) wt during the transesterification process of biodiesel. Although glycerol in its purified form has a number of uses, crude glycerol obtained from the biodiesel industry contains many impurities and requires expensive purification processes resulting in vast amounts of glycerol without adequate destination which are causing rise to many environmental concerns. Large scale applications of glycerol are necessary to accompany its production. Polyesters obtained via the polycondensation of glycerol with aromatic acids were prepared in different ratios. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to investigate thermal stability. The composite structure was characterized by Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffraction (DRX). These aromatic polyesters could offer a low cost environmentally compatible material for the production of components such as tiles, boards, sanitary vases and sinks for the construction industry.

Carvalho, Ricardo F.; Jose, Nadia M.; Carvalho, Adriana L. S.; Miranda, Cleidiene S.; Thomas, Natasha I. R.

2011-12-01

77

Hydrolytic kinetics of biodegradable polyester monolayers  

SciTech Connect

The rate of hydrolysis of Langmuir monolayer films of a series of biodegradable polyesters was investigated at the air/water interface. The present study investigated parameters such as degradation medium, pH, and time. The hydrolysis of polyester monolayers strongly depended on both the degradation medium used to control subphase pH and the concentration of active ions. Under the conditions studied here, polymer monolayers showed faster hydrolysis when they were exposed to a basic subphase rather than that of acidic or neutral subphase. The basic (pH = 10) hydrolysis of [poly(l-lactide)/polycaprolactone](l-PLA/PCL 1/1 by mole) blend was faster than that of each homopolymer at the initial stage. This result is explained by increasing numbers of base attack sites per unit area owing to the very slow hydrolysis of PCL, a dilution effect on the concentration of l-PLA monolayers. Conversely the hydrolytic behavior of l-lactide-co-caprolactone (1/1 by mole) was similar to that of PCL even though the chemical compositions of the blend and the copolymer are very similar to each other. The resistance of the copolymer to hydrolysis might be attributed to the hydrophobicity and the steric hindrance of caprolactone unit in the copolymer.

Lee, W.K.; Gardella, J.A. Jr.

2000-04-04

78

Phase separation during radiation crosslinking of unsaturated polyester resin  

NASA Astrophysics Data System (ADS)

Phase separation during radiation-initiated crosslinking of unsaturated polyester resin was studied. Residual reactivity of liquid phases and gels of partially cured samples was determined by DSC. Uncured resin and liquid phases showed double reaction exotherm, gels had a single maximum that corresponded to higher-temperature maximum of liquid parts. The lower-temperature process was attributed to styrene-polyester copolymerization. At higher temperatures, polyester unsaturations that remained unreacted due to microgel formation homopolymerized. FTIR revealed different composition of phases. In thicker samples, reaction heat influenced microgel formation causing delayed appearance of gel and faster increase in conversion.

Puci?, Irina; Ranogajec, Franjo

2003-06-01

79

Studies on moisture transmission properties of PV-blended fabrics  

Microsoft Academic Search

Moisture transmission properties are most important for fabric comfort. We have studied the moisture transmission properties of the plain-woven fabric produced with polyester–viscose-(PV) blended yarns. PV-blended yarns of varying blend proportion, yarn count and twist levels have been used for fabric manufacture. A three-variable Box and Behnken factorial design technique has been used to study the interaction effects of the

Brojeswari Das; A. Das; V. K. Kothari; R. Fangueiro; M. de Araújo

2009-01-01

80

Block copolymer of poly(ester amide) and polyesters: synthesis, characterization, and in vitro cellular response.  

PubMed

In order to expand the properties and applications of aliphatic absorbable polyesters, a new biodegradable block copolymer family, poly(ester amide)-b-poly(?-caprolactone) (PEA-b-PCL), was synthesized and characterized. These copolymers were synthesized by first preparing l-phenylalanine-based poly(ester amide) macroinitiators (Phe-PEAs) with free amine end groups via a solution polycondensation. The amine-terminated Phe-PEA macroinitiators were then used to initiate the ring-opening polymerization of ?-caprolactone monomer to prepare the PEA-b-PCL copolymers. The molecular weight (MW) of PEA-b-PCLs can be well controlled by adjusting the Phe-PEA MW and weight ratio of ?-caprolactone to Phe-PEA, and ranged from 7 to 50kgmol(-1). The copolymers' structure and properties were characterized by various physicochemical methods, such as nuclear magnetic resonance, gel permeation chromatography and solubility testing. The in vitro enzymatic biodegradation tests were performed to evaluate the biodegradation rate of the copolymers. The results showed that the introduction of Phe-PEA to PCL did not significantly change the degradation rate of PCL. Biological studies were conducted to assess the polymer's biological properties, like supporting the cell attachment and proliferation, and inflammation response. The results showed that the bovine aortic endothelial cells had very good attachment and proliferation performance on PEA-b-PCL coating surface. TNF-? release profiles showed that PEA-b-PCL exhibited a muted J774 macrophage inflammatory response. PMID:22842040

Wu, Jun; Chu, Chih-Chang

2012-12-01

81

21 CFR 177.2420 - Polyester resins, cross-linked.  

Code of Federal Regulations, 2013 CFR

...of this section 6. Miscellaneous materials: Castor oil, hydrogenated ?-Methylstyrene Polyethylene glycol 6000 Silicon dioxide Wax, petroleum Complying with § 178.3710 of this chapter. (c) The cross-linked polyester...

2013-04-01

82

21 CFR 177.2420 - Polyester resins, cross-linked.  

Code of Federal Regulations, 2014 CFR

...of this section 6. Miscellaneous materials: Castor oil, hydrogenated ?-Methylstyrene Polyethylene glycol 6000 Silicon dioxide Wax, petroleum Complying with § 178.3710 of this chapter. (c) The cross-linked polyester...

2014-04-01

83

21 CFR 177.2420 - Polyester resins, cross-linked.  

Code of Federal Regulations, 2012 CFR

...of this section 6. Miscellaneous materials: Castor oil, hydrogenated ?-Methylstyrene Polyethylene glycol 6000 Silicon dioxide Wax, petroleum Complying with § 178.3710 of this chapter. (c) The cross-linked polyester...

2012-04-01

84

Hydrolyzable polyester resins, varnishes and coating compositions containing the same  

DOEpatents

Preparation of hydrolyzable polyester resin comprising reacting polycarboxylic acid and polyhydric alcohol components, which is characterized by using, as at least part of said polyhydric alcohol component, a metallic salt of hydroxy carboxylic acid of the formula defined and effecting the polycondensation at a temperature which is no more than the decomposition temperature of said metallic salt. The polyester resins are useful as resinous vehicle of varnishes and antifouling paints.

Yamamori, Naoki (Minoo, JP); Yokoi, Junji (Nara, JP); Yoshikawa, Motoyoshi (Nara, JP)

1984-01-01

85

Rheological behaviour of nanocellulose reinforced unsaturated polyester nanocomposites.  

PubMed

Nanocellulose (NC) reinforced unsaturated polyester (UPR) composites were prepared by mechanical mixing process. Effect of isora nanocellulose on the properties of polyester composites has been studied in detail. Rheological properties of unsaturated polyester resin suspensions containing various amounts (0.5, 1 and 3wt%) of nanocellulose were investigated by oscillatory rheometer with parallel plate geometry. Analysis of curing revealed that the time required for gelation in NC filled UPR is lower than neat resin, which describe the catalytic action of NC on cure reaction. NC reinforced polyester suspensions showed shear thinning behaviour initially and at higher shear rates they showed Newtonian behaviour. Tensile and impact properties showed superior behaviour revealing improved interfacial bonding between nanofiller and the polymer matrix. With respect to the neat polyester the percentage increase in tensile strength of 0.5wt% NC reinforced composite is 57%. Optical and atomic force microscopic studies confirmed that the dispersion state of NC within the polyester matrix was adequate. Maximum glass transition temperature is obtained for 0.5wt% NC reinforced composite, which showed an increase of 10°C than neat resin. PMID:24877644

Chirayil, Cintil Jose; Mathew, Lovely; Hassan, P A; Mozetic, Miran; Thomas, Sabu

2014-08-01

86

Tunable Chemical Release from Polyester Thin Film by Photocatalytic Zinc Oxide and Doped LiYF4 Upconverting Nanoparticles.  

PubMed

Once manufactured or implanted, polyester release kinetics tend to be fixed with little modulation possible for optimal local chemical concentrations. Here, a typical implantable polyester was fabricated into thin films (?50 ?m thick) with additives of photocatalytic ZnO nanoparticles, lanthanide-doped LiYF4 nanoparticle upconverting nanoparticles, or a combination thereof and irradiated with either 6 mW ultraviolet (365 nm) light emitting diodes or 50 mW near-infrared (980 nm) laser diodes to induce polymer photooxidation. Irradiated polyester films with the aforementioned photoadditives had enhanced release kinetics up to 30 times more than nonirradiated, neat films with extended release times of 28 days. Near-infrared, ZnO-mediated photocatalysis had the highest light on/light off ratio release kinetics of 15.4, while doped LiYF4 upconversion nanoparticles paired with ZnO nanoparticles had the highest linear R(2) correlation of 0.98 with respect to duty cycle and release kinetics. Future applications of the technology will aim toward modulation of previously developed polymeric reagents/drugs for real-time, feedback-optimized release. PMID:25474498

Cheng, Ting; Ortiz, Raphael Francois; Vedantham, Kumar; Naccache, Rafik; Vetrone, Fiorenzo; Marks, Robert S; Steele, Terry W J

2015-01-12

87

Persistence of Nosocomial Pathogens on Various Fabrics  

PubMed Central

Objective: Fabrics can become contaminated with high numbers of microorganisms that may be pathogenic to patients in a hospital setting and can play an important role in the chain of infection. The aim of this study was to investigate the survival of several clinical bacterial and fungal isolates on several fabrics commonly used in hospitals. Materials and Methods: Bacterial and fungal survival was tested on the following materials, each of which are commonly used in our hospital: 100% smooth cotton, 60% cotton-40% polyester, 100% wool and 100% silk. One isolate each of Candida albicans, Candida tropicalis, Candida krusei, Candida glabrata, Candida parapsilosis, Geotrichum candidum, Aspergillus fumigatus, Cryptococcus neoformans, vancomycin resistant Enterococcus faecium (VRE, methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL) positive Escherichia coli, inducible beta-lactamase (IBL) positive Pseudomonas aeruginosa, IBL-positive Acinetobacter baumannii and Stenotrophomonas maltophilia were used to contaminate fabrics. The survival of these microorganisms was studied by testing the fabric swatches for microbial growth. Results: The median survival times for all the tested bacteria and fungi were as follows: 26 days on cotton, 26.5 days on cotton-polyester, 28 days on silk, and 30 days on wool. Among the bacterial species tested, E. faecium had the longest survival time on cotton-polyester fabrics. For the fungal isolates, it was observed that C. tropicalis and C. krusei survived for the shortest amount of time on cotton fabrics in the present study. Conclusion: This survival data indicate that pathogenic microorganisms can survive from days to months on commonly used hospital fabrics. These findings indicate that current recommendations for the proper disinfection or sterilization of fabrics used in hospitals should be followed to minimize cross-contamination and prevent nosocomial infections.

Koca, Ozlem; Altoparlak, Ulku; Ayyildiz, Ahmet; Kaynar, Hasan

2012-01-01

88

Study of the electrical properties of novel hybrid organic–inorganic conducting textiles of polypyrrole-phosphotungstate-polyester using electrochemical impedance spectroscopy  

Microsoft Academic Search

The electrical properties of novel hybrid organic–inorganic conducting fabrics of polyester (PES) coated with polypyrrole-PW12O403? (PPy-POM) have been tested for dry samples and specimens immersed in different pH solutions (1, 7, and 13). Electrical properties changes were measured by means of electrochemical impedance spectroscopy (EIS). This study showed that organic–inorganic PES-PPy-POM conducting textiles act as electronic conductors with semiconducting nature.

J. Bonastre; J. Molina; A. I. del Río; J. C. Galván; F. Cases

2011-01-01

89

Biodegradation of Polyester Polyurethane by Endophytic Fungi?  

PubMed Central

Bioremediation is an important approach to waste reduction that relies on biological processes to break down a variety of pollutants. This is made possible by the vast metabolic diversity of the microbial world. To explore this diversity for the breakdown of plastic, we screened several dozen endophytic fungi for their ability to degrade the synthetic polymer polyester polyurethane (PUR). Several organisms demonstrated the ability to efficiently degrade PUR in both solid and liquid suspensions. Particularly robust activity was observed among several isolates in the genus Pestalotiopsis, although it was not a universal feature of this genus. Two Pestalotiopsis microspora isolates were uniquely able to grow on PUR as the sole carbon source under both aerobic and anaerobic conditions. Molecular characterization of this activity suggests that a serine hydrolase is responsible for degradation of PUR. The broad distribution of activity observed and the unprecedented case of anaerobic growth using PUR as the sole carbon source suggest that endophytes are a promising source of biodiversity from which to screen for metabolic properties useful for bioremediation. PMID:21764951

Russell, Jonathan R.; Huang, Jeffrey; Anand, Pria; Kucera, Kaury; Sandoval, Amanda G.; Dantzler, Kathleen W.; Hickman, DaShawn; Jee, Justin; Kimovec, Farrah M.; Koppstein, David; Marks, Daniel H.; Mittermiller, Paul A.; Núñez, Salvador Joel; Santiago, Marina; Townes, Maria A.; Vishnevetsky, Michael; Williams, Neely E.; Vargas, Mario Percy Núñez; Boulanger, Lori-Ann; Bascom-Slack, Carol; Strobel, Scott A.

2011-01-01

90

Biodegradation of polyester polyurethane by endophytic fungi.  

PubMed

Bioremediation is an important approach to waste reduction that relies on biological processes to break down a variety of pollutants. This is made possible by the vast metabolic diversity of the microbial world. To explore this diversity for the breakdown of plastic, we screened several dozen endophytic fungi for their ability to degrade the synthetic polymer polyester polyurethane (PUR). Several organisms demonstrated the ability to efficiently degrade PUR in both solid and liquid suspensions. Particularly robust activity was observed among several isolates in the genus Pestalotiopsis, although it was not a universal feature of this genus. Two Pestalotiopsis microspora isolates were uniquely able to grow on PUR as the sole carbon source under both aerobic and anaerobic conditions. Molecular characterization of this activity suggests that a serine hydrolase is responsible for degradation of PUR. The broad distribution of activity observed and the unprecedented case of anaerobic growth using PUR as the sole carbon source suggest that endophytes are a promising source of biodiversity from which to screen for metabolic properties useful for bioremediation. PMID:21764951

Russell, Jonathan R; Huang, Jeffrey; Anand, Pria; Kucera, Kaury; Sandoval, Amanda G; Dantzler, Kathleen W; Hickman, DaShawn; Jee, Justin; Kimovec, Farrah M; Koppstein, David; Marks, Daniel H; Mittermiller, Paul A; Núñez, Salvador Joel; Santiago, Marina; Townes, Maria A; Vishnevetsky, Michael; Williams, Neely E; Vargas, Mario Percy Núñez; Boulanger, Lori-Ann; Bascom-Slack, Carol; Strobel, Scott A

2011-09-01

91

Shock Wave Profiles in Glass Reinforced Polyester  

NASA Astrophysics Data System (ADS)

The promise of lightweight armor which is also structurally robust is of particular importance to the Army for future combat vehicles. Fiber reinforced organic matrix composites such as Glass Reinforced Polyester (GRP) are being considered for this purpose due to their lower density and promising dynamic response. The work discussed here extends the prior work of Boteler who studied the delamination strength of GRP and Dandekar and Beaulieu who investigated the compressive and tensile strengths of GRP. In a series of shock wave experiments, the wave profile was examined as a function of propagation distance in GRP. Uniaxial strain was achieved by plate impact in the ARL 102 mm bore single-stage light gas gun. Embedded polyvinylidene flouride (PVDF) stress-rate gauges provided a stress history at three unique locations in the GRP and particle velocity history was recorded with VISAR. The use of Lagrange gauges embedded in such a manner provides a means of calculating the constitutive relationships between specific volume, stress, and particle velocity uniquely with no prior assumptions of the form of constitutive relation. The Lagrangian analysis will be discussed and compared to Lagrangian hydrocode (EPIC) results employing a model to describe the viscoelastic response of the composite material in one-dimension.

Boteler, J. Michael; Rajendran, A. M.; Grove, David

1999-06-01

92

Polyester mooring for the Mad Dog spar—design issues and other considerations  

Microsoft Academic Search

The Mad dog project will use a polyester mooring system on the drilling and production truss spar. This will be the first use of a permanent polyester mooring system on a Floating Production System (FPS) outside of Brazil and the first time polyester has been used on a spar. As such, there were many challenges, which include:•Regulatory approval.•Designing a mooring

David Petruska; Jeff Geyer; Rick Macon; Michael Craig; Alex Ran; Neil Schulz

2005-01-01

93

Radiation cured polyester compositions containing metal-properties  

NASA Astrophysics Data System (ADS)

The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them.

Szali?ska, H.; Pietrzak, M.; Gonerski, A.

94

Reticulation Study and Molding of Unsaturated Polyester Composites  

NASA Astrophysics Data System (ADS)

This paper describes a laboratory experiment involving polyester composites, and especially sheet molding compounds (SMC), to investigate several aspects of composite science. The SMC contain an unsaturated polyester resin (blended with styrene monomer), fillers (calcium carbonate), and glass-fiber reinforcement. The mix also contains a peroxide catalyst and other additives. During the practical work, the reticulation reaction of SMC is studied by differential scanning calorimetry to optimize the conditions (temperature and time) of the molding process. The SMC are then molded by compression under a heating press. SMC composite appears to be a choice material for laboratory study because both chemistry and the molding process can be investigated.

Bistac, S.

1999-11-01

95

Modification of polyester resins with active mineral fillers  

Microsoft Academic Search

The technological and operational properties of polyester resins, unmodified and modified with new freely disperse fillers, were investigated. It was found that modification causes greater dependence of the viscosity on the fatigue load and acceleration of the curing reaction and an increase in the exothermic effect by 2.5-4.5 times. In addition, the strength properties of the modified composites and the

A. V. Murafa; N. I. Bobyreva; V. G. Khozin

1996-01-01

96

Production of a polyester degrading extracellular hydrolase from Thermomonospora fusca.  

PubMed

The production of a polyester-degrading hydrolase from the thermophilic actinomycete Thermomonospora fusca was investigated with regard to its potential technical application. Only in the presence of a polyester (random aliphatic-aromatic copolyester from 1,4-butanediol, terephthalic acid, and adipic acid with around 40-50 mol % terephthalic acid in the acid component), the excretion of the extracellular enzyme could be achieved with an optimized synthetic medium using pectin and NH(4)Cl as nitrogen source. Compared to complex media, a significantly higher specific activity at comparable volumetric yields could be obtained, thus reducing the expenditure for purification. The activity profile in the medium is controlled by a complex process involving (1) induction of enzyme excretion, (2) enzyme adsorption on the hydrophobic polyester surface, (3) inhibition of enzyme generation by monomers produced by polyester cleavage, and (4) enzyme denaturation. Diafiltration with cellulose acetate membranes as the sole downstream processing step led to a product of high purity and with sufficient yield (60% of total activity). Scaling-up from shaking flasks to a fermentor scale of 100 L revealed no specific problems. However, the excretion of the hydrolase by the actinomycete turned out to be inhibited by the degradation products (monomers) of the aliphatic-aromatic copolyester used as inductor for the enzyme production. The crude enzyme exhibited generally similar properties (temperature and pH optimum) as the highly purified hydrolase described previously; however, the storage capability and thermal stability is improved when the crude enzyme solution is diafiltrated. PMID:12363342

Gouda, Mona K; Kleeberg, Ilona; van den Heuvel, Joop; Müller, Rolf-Joachim; Deckwer, Wolf-Dieter

2002-01-01

97

Degradation Characterization of Aliphatic POLYESTERS—IN Vitro Study  

NASA Astrophysics Data System (ADS)

The most popular and important biodegradable polymers are aliphatic polyesters, such as polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polyhydoxyalkanoates (PHA's) and polyethylene oxide (PEO). However, each of these has some shortcomings which restrict its applications. Blending techniques are an extremely promising approach which can improve or tune the original properties of the polymers[1]. Aliphatic polyesters are a central class of biodegradable polymers, because hydrolytic and/or enzymatic chain cleavage of these materials leads to ?-hydroxyacids, which in most cases are ultimately metabolized in human body. This is particularly useful for controlled release devices and for other biomedical applications like suture fibers and ligaments. For aliphatic polyesters, hydrolysis rates are affected by the temperature, molecular structure, and ester group density as well as by the species of enzyme used. The degree of crystallinity may be a crucial factor, since enzymes attack mainly the amorphous domains of a polymer. Four different aliphatic polyesters were characterized in terms of degradation. Sutures fibers of PGA-PCL, PGA, PLA-PCL and PDO were used in this study. Weight loss, pH, molecular weight, crystallinity and strength were measured after six stages of incubation in distilled water, physiological saline and phosphate buffer solution (PBS). Degradation rate was determined, using a first order kinetic equation for all materials in the three incubation media. A relatively wide range of mechanical properties and degradation rates were observed among the materials studied. PBS was the most aggressive environment for the majority of cases.

Vieira, A. C.; Vieira, J. C.; Guedes, R. M.; Marques, A. T.

2008-08-01

98

Dynamic mechanical analysis of banana fiber reinforced polyester composites  

Microsoft Academic Search

The dynamic mechanical analysis of banana fiber reinforced polyester composites was carried out with special reference to the effect of fiber loading, frequency and temperature. The intrinsic properties of the components, morphology of the system and the nature of interface between the phases determine the dynamic mechanical properties of the composite. At lower temperatures (in the glassy region), the E?

Laly A. Pothan; Zachariah Oommen; Sabu Thomas

2003-01-01

99

Amphiphilic Dendritic Molecules: Hyperbranched Polyesters with Alkyl-Terminated Branches  

E-print Network

Amphiphilic Dendritic Molecules: Hyperbranched Polyesters with Alkyl-Terminated Branches X. Zhai, S for a controlling amphiphilic balance of hyperbranched cores with a degree of branching of 50%. Even for imperfect dendritic molecules capable of forming organized aggregates and monolayers at interfaces, amphiphilic

Vakni, David

100

Influence of weft-knitted tubular fabric on radial mechanical property of coaxial three-layer small-diameter vascular graft.  

PubMed

The goal of this study was to evaluate the radial mechanical property of the small-diameter polyurethane vascular grafts reinforced by weft-knitted tubular polyester/spandex fabrics. The polyester/spandex tubular fabrics with different blend ratios were prepared on a weft-knitting machine to reinforce small-diameter polyurethane vascular grafts. Phase separation technique was employed to produce coaxial three-layer small-diameter polyurethane vascular grafts at room temperature. Morphology of the polyurethane vascular grafts was examined by scanning electron microscope (SEM), and micropores were observed on both inner and cross section surfaces. Radial tensile property and compliance of small-diameter polyurethane vascular grafts with and without reinforcement by polyester/spandex tubular fabrics were characterized. The effect of polyester/spandex tubular fabric on the mechanical property of polyurethane vascular grafts was studied. The results indicated that the radial tensile strength of the vascular graft was improved by the tubular fabric, and that the influence of tubular fabric on compliance was small compared to that of wall thickness. It was notable that the wall thickness of the vascular grafts was a major factor in controlling the compliance in the radial direction. Therefore, a coaxial three-layer small-diameter polyurethane vascular graft with excellent compliance and tensile strength could be obtained by controlling the wall thickness and using polyester/spandex fabric as reinforcement. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 342-349, 2012. PMID:22113920

Yang, Hongjun; Zhu, Guocheng; Zhang, Zhen; Wang, Zhenzhen; Fang, Jian; Xu, Weilin

2012-02-01

101

Antibacterial and Laundering Properties of AMS and PHMB as Finishing Agents on Fabric for Health Care Workers' Uniforms  

Microsoft Academic Search

This study examined whether antibacterial finishes can effectively reduce the presence of bacteria on fabric used for health care workers' uniforms (HCWUs). The specific objectives of this research were (a) to compare the antibacterial property (percentage bacterial reduction) of a 65\\/35 polyester\\/cotton blend fabric treated with two commercially available antibacterial agents, AEGIS Microbe Shield (AMS) and polyhexamethylene biguanide (PHMB), before

Jessie H. Chen-Yu; Darlene M. Eberhardt; Doris H. Kincade

2007-01-01

102

Test method for evaluating fabric flammability and predicted skin burn injury in microgravity  

Microsoft Academic Search

To address fire safety concerns associated with the use of flammable fabrics during space travel, an apparatus was designed\\u000a to be flown on low-gravity parabolic aircraft flights in order to assess the flammability of cotton and 50% cotton\\/50% polyester\\u000a fabrics, and the resulting skin burn injury that would occur if these fabrics were to ignite. The apparatus, modelled after\\u000a a

Jane M. Cavanagh; David A. Torvi; Kamiel S. Gabriel; Gary. A. Ruff

2006-01-01

103

Assessment of a Polyester-Covered Nitinol Stent in the Canine Aorta and Iliac Arteries  

SciTech Connect

Purpose: To evaluate the patency and healing characteristics of a woven polyester fabric-covered stent in the canine model.Methods: Twenty-four self-expanding covered stents were placed in the infrarenal aorta and bilateral common iliac arteries of eight dogs and evaluated at 1 (n = 2), 3 (n = 2), and 6 (n = 4) months. Stent assessment was done using angiography prior to euthanasia, and light and scanning electron microscopy.Results: Angiographically, just prior to euthanasia, 8 of 8 aortic and 14 of 16 iliac endovascular covered stents were patent. Histologically, the stented regions showed complete endothelialization 6 months after graft implantation. A neointima had formed inside the stented vessel regions resulting in complete encasement of the fabric-covered stent by 3 months after graft implantation. Medial compression with smooth muscle cell atrophy was present in all stented regions. Explanted stent wires, examined by scanning electron microscopy, showed pitting but no cracks or breakage.Conclusion: The covered stent demonstrated predictable healing and is effective in preventing stenosis in vessels 10.0 mm or greater in diameter but does not completely preclude stenosis in vessels 6.0 mm or less in diameter.

Castaneda, Flavio [Department of Radiology, University of Illinois College of Medicine at Peoria, 1 Illini Drive, Peoria, IL 61656 (United States); Ball-Kell, Susan M. [Department of Pathology, University of Illinois College of Medicine at Peoria, 1 Illini Drive, Peoria, IL 61656 (United States); Young, Kate; Li Ruizong [Department of Radiology, University of Illinois College of Medicine at Peoria, 1 Illini Drive, Peoria, IL 61656 (United States)

2000-09-15

104

Amino alcohol-based degradable poly(ester amide) elastomers  

PubMed Central

Currently available synthetic biodegradable elastomers are primarily composed of crosslinked aliphatic polyesters, which suffer from deficiencies including (1) high crosslink densities, which results in exceedingly high stiffness, (2) rapid degradation upon implantation, or (3) limited chemical moieties for chemical modification. Herein, we have developed poly(1,3-diamino-2-hydroxypropane-co-polyol sebacate)s, a new class of synthetic, biodegradable elastomeric poly(ester amide)s composed of crosslinked networks based on an amino alcohol. These crosslinked networks feature tensile Young’s modulus on the order of 1 MPa and reversable elongations up to 92%. These polymers exhibit in vitro and in vivo biocompatibility. These polymers have projected degradation half-lives up to 20 months in vivo. PMID:18295329

Bettinger, Christopher J.; Bruggeman, Joost P.; Borenstein, Jeffrey T.; Langer, Robert S.

2009-01-01

105

Thermo-mechanical properties of polyester mortar using recycled PET  

SciTech Connect

The thermo-mechanical properties of polyester mortar (PM) using unsaturated polyester resins based on recycled PET are investigated in this paper (the recycled PET waste is mainly obtained from used plastic beverage bottles). The use of recycled PET in PM formulation is important because it helps produce good quality PM at a relatively low cost, save energy and alleviate an environmental problem posed by plastic wastes. PM construction applications include the repair of dams, piers, runways, bridges and other structures. Test results show that the effective use of PM overlays on portland cement concrete slabs is best achieved by utilizing flexible resins with low modulus and high elongation capacity at failure. The use of flexible resins in PM production is especially important in situations involving large thermal movements.

Rebeiz, K.S.; Craft, A.P. [Lafayette Coll., Easton, PA (United States)

1997-07-01

106

Biosynthesis and biodegradation of 3-hydroxypropionate-containing polyesters.  

PubMed

3-Hydroxypropionate (3HP) is an important compound in the chemical industry, and the polymerized 3HP can be used as a bioplastic. In this review, we focus on polyesters consisting of 3HP monomers, including the homopolyester poly(3-hydroxypropionate) and copolyesters poly(3-hydroxybutyrate-co-3-hydroxypropionate), poly(3-hydroxypropionate-co-3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate), poly(4-hydroxybutyrate-co-3-hydroxypropionate-co-lactate), and poly(3-hydroxybutyrate-co-3-hydroxypropionate-co-4-hydroxybutyrate-co-lactate). Homopolyesters like poly(3-hydroxybutyrate) are often highly crystalline and brittle, which limits some of their applications. The incorporation of 3HP monomers reduces the glass transition temperature, the crystallinity, and also, at up to 60 to 70 mol% 3HP, the melting point of the copolymer. This review provides a survey of the synthesis and physical properties of different polyesters containing 3HP. PMID:20543057

Andreessen, Björn; Steinbüchel, Alexander

2010-08-01

107

Tandem synthesis of alternating polyesters from renewable resources  

PubMed Central

The vast majority of commodity materials are obtained from petrochemical feedstocks. These resources will plausibly be depleted within the next 100 years, and the peak in global oil production is estimated to occur within the next few decades. In this regard, biomass represents an abundant carbon-neutral renewable resource for the production of polymers. Here we report a new strategy, based on tandem catalysis, to obtain renewable materials. Commercially available complexes are found to be efficient catalysts for alternating polyesters from the cyclization of dicarboxylic acids followed by alternating copolymerization of the resulting anhydrides with epoxides. This operationally simple method is an attractive strategy for the production of new biodegradable polyesters. PMID:22158441

Robert, Carine; de Montigny, Frédéric; Thomas, Christophe M.

2011-01-01

108

Surface Characterization of Aliphatic Polyester -g- Phosphorylcholine Copolymers  

NASA Astrophysics Data System (ADS)

In order to control biodegradation behavior of a class of polyesters, hydrophilic functional groups were grafted onto the main chains. Phosphorylcholine (PC) molecules with azide attached at the end were synthesized. Due to their excellent biocompatibility and hydrophilicity, they have been covalently coupled to biodegradable aliphatic polyesters via a ``click'' cycloaddition reaction to produce amphiphilic graft copolymers. A series of copolymers were prepared by varying the molar incorporation of PC groups. Surface properties of the copolymers were examined to further explore their applications in drug delivery systems. Grazing angle reflection infrared spectroscopy was employed to determine segmental orientation at the film surface. XPS was used to verify surface composition. A water adsorption experiment was carried out to determine the water permeation rate. The improvement in hydrophilicity was confirmed by a water contact experiment. Results indicate that the graft copolymers were promising in drug delivery systems.

Zhang, Xiongfei; Emrick, Todd; Hsu, Shaw L.

2007-03-01

109

Biosynthesis and Biodegradation of 3-Hydroxypropionate- Containing Polyesters?  

PubMed Central

3-Hydroxypropionate (3HP) is an important compound in the chemical industry, and the polymerized 3HP can be used as a bioplastic. In this review, we focus on polyesters consisting of 3HP monomers, including the homopolyester poly(3-hydroxypropionate) and copolyesters poly(3-hydroxybutyrate-co-3-hydroxypropionate), poly(3-hydroxypropionate-co-3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate), poly(4-hydroxybutyrate-co-3-hydroxypropionate-co-lactate), and poly(3-hydroxybutyrate-co-3-hydroxypropionate-co-4-hydroxybutyrate-co-lactate). Homopolyesters like poly(3-hydroxybutyrate) are often highly crystalline and brittle, which limits some of their applications. The incorporation of 3HP monomers reduces the glass transition temperature, the crystallinity, and also, at up to 60 to 70 mol% 3HP, the melting point of the copolymer. This review provides a survey of the synthesis and physical properties of different polyesters containing 3HP. PMID:20543057

Andreeßen, Björn; Steinbüchel, Alexander

2010-01-01

110

Compatibility and mechanical properties of blends of polystyrene with biodegradable polyesters  

Microsoft Academic Search

Biodegradable polyesters allow the development of acceptable bio-composites and bio-blends from agricultural-based raw materials without impairing their biodegradability and other useful properties. The tensile properties of binary blends of polystyrene (PS) with the biodegradable polyesters polycaprolactone (PCL), d,l-polylactic acid (PLA), and Eastar Bio Ultra (EBU) were investigated. Blend composition ranging from pure PS to pure biodegradable polyester, in 25% increments,

G. Biresaw; C. J. Carriere

2004-01-01

111

Perforation of clamped, woven E-glass\\/polyester panels  

Microsoft Academic Search

Analytical solutions to predict the perforation of fully clamped, woven E-glass\\/polyester panels subjected to static indentation by a blunt cylinder were derived. Three panel aspect ratios of 12.5, 25 and 50 were considered in order to show how modes of failure vary with panel flexibility. The analytical solutions for the deformation and interlaminar shear stresses compared well to finite element

Michelle S. Hoo Fatt; Chunfu Lin

2004-01-01

112

Epoxidation of polyesters of tetrahydrophthalic acid and unsaturated alkyd resins  

Microsoft Academic Search

Summary  New polyepoxides are reported which are epoxidation products of unsaturated polyesters. These polyepoxides are unique in that\\u000a they may be formulated to have a large number of epoxide groups per molecule; 10 or more may be practically obtained.\\u000a \\u000a Anin situ process for the formation of peracetic acid, using dehydrated cation exchange resin of the styrene-divinyl benzene sulfonic\\u000a acid type, has

John W. Pearce; John Kawa

1957-01-01

113

Conductive Papers Containing Metallized Polyester Fibers for Electromagnetic Interference Shielding  

Microsoft Academic Search

Conductive papers were developed for preventing or reducing electromagnetic interference (EMI), and their shielding efficiency was evaluated. This type of conductive paper consists of wood pulp, synthetic pulp and metallized polyester fibers (0.5–2.0 mm long and 14 µm in diameter) whose surfaces are coated with nickel alone (Ni-PET) or copper and nickel double layers (Ni-Cu-PET) by electroless plating. In this

Shunichi Shinagawa; Yaomi Kumagai; Kei Urabe

1999-01-01

114

Assessment of perylene-based profluorescent nitroxides for monitoring polyester degradation upon weathering .  

E-print Network

??A profluorescent nitroxide possessing an isoindoline nitroxide moiety linked to a perylene fluorophore was developed to monitor radical mediated degradation of melamine-formaldehyde crosslinked polyester coil… (more)

SYLVESTER, PAUL

2013-01-01

115

NIR Characterization and Measurement of the Cotton Content of Dyed Blend Fabrics  

Technology Transfer Automated Retrieval System (TEKTRAN)

Near Infrared (NIR) spectroscopy has been used extensively for several years in the fiber, textiles, and textile auxiliaries industries. NIR techniques for the measurement of cotton-polyester (PET) blend content have concentrated on yarn slivers and greige fabrics rather than the more much difficult...

116

A novel method for applying reduced graphene oxide directly to electronic textiles from yarns to fabrics.  

PubMed

Conductive, flexible, and durable reduced RGO textiles with a facile preparation method are presented. BSA proteins serve as universal adhesives for improving the adsorption of GO onto any textile, irrespective of the materials and the surface conditions. Using this method, we successfully prepared various RGO textiles based on nylon-6 yarns, cotton yarns, polyester yarns, and nonwoven fabrics. PMID:23946273

Yun, Yong Ju; Hong, Won G; Kim, Wan-Joong; Jun, Yongseok; Kim, Byung Hoon

2013-10-25

117

Wood fiber reinforced bacterial bioplastic composites: Fabrication and performance evaluation  

Microsoft Academic Search

Renewable resource based green composites were prepared from wood fiber and a bacterial polyester i.e., polyhydroxybutyrate-co-valerate (PHBV) via extrusion–injection molding process. The fabricated PHBV based biocomposites contained 10–40wt% of the maple wood fiber. The effects of increasing wood fiber weight contents on mechanical, thermomechanical and morphological properties of the PHBV based biocomposites were evaluated. The tensile and flexural modulus of

Sanjeev Singh; A. K. Mohanty

2007-01-01

118

ADBD plasma surface treatment of PES fabric sheets  

NASA Astrophysics Data System (ADS)

Plasma treatment of textile fabrics is investigated as an alternative to the environmentally hazardous wet chemical fabric treatment and pretreatment processes. Plasma treatment usually results in modification of the uppermost atomic layers of a material surface and leaves the bulk characteristics unaffected. It may result in desirable surface modifications, e.g. surface etching, surface activation, cross-linking, chain scission and oxidation. Presented paper contains results of the applicability study of the atmospheric pressure dielectric discharge (ADBD), i.e. dielectric barrier discharge sustaining in air at atmospheric pressure and ambient temperature for synchronous treatment of several sheets of fabric. For tests sheets of polyester fabric were used. Effectivity of the modification process was determined with hydrophilicity measurements evaluated by means of the drop test. Hydrophilicity of individual sheets of fabric has distinctly increased after plasma treatment. Plasma induced surface changes of textiles were also proven by identification of new functional groups at the modified polyester fabric surface. Existence of new functional groups was detected by ESCA scans. For verification of surface changes we also applied high-resolution microphotography. It has shown distinct variation of the textile surface after plasma treatment. Important aspect for practical application of the plasma treatment is the modification effect time-stability, i.e. time stability of acquired surface changes of the fabric. The recovery of hydrophobicity was fastest in first days after treatment, later gradually diminished until reached almost original untreated state.

Píchal, J.; Klenko, Y.

2009-08-01

119

Nanoindentation and adhesion of sol-gel-derived hard coatings on polyester  

E-print Network

on the plastic surface. Nanoindentation analysis revealed that the coatings have a surface hardness up to 2.5 ± 0Nanoindentation and adhesion of sol-gel-derived hard coatings on polyester C.M. Chan, G.Z. Cao,a) H coatings on modified polyester substrates. The silica network was modified by incorporating an organic

Cao, Guozhong

120

Enzymatic saccharification coupling with polyester recovery from cotton-based waste textiles by phosphoric acid pretreatment.  

PubMed

In order to recycle the cotton-based waste textiles, a novel process was designed for pretreating waste textiles with phosphoric acid to recover polyester and fermentable sugar. The effects of pretreatment conditions including, phosphoric acid concentration, pretreatment temperature, time, and ratio of textiles and phosphoric acid were thoroughly investigated. Results indicated the mentioned four factors had significant influences on sugar and polyester recovery. Almost complete polyester recovery was achieved by enhancing phosphoric acid concentration, temperature and pretreatment time or reducing the ratio of textiles and phosphoric acid. However, these behaviors decreased the sugar recovery seriously. 100% polyester recovery with a maximum sugar recovery of 79.2% was achieved at the optimized conditions (85% phosphoric acid, 50°C, 7h, and the ratio of 1:15). According to the technical and cost-benefit analysis, it was technically feasible and potentially profitable to recover polyester and sugar from waste textiles by phosphoric acid pretreatment. PMID:23313669

Shen, Fei; Xiao, Wenxiong; Lin, Lili; Yang, Gang; Zhang, Yanzong; Deng, Shihuai

2013-02-01

121

New Approach for Imparting Antimicrobial Properties for Polyamide and Wool Containing Fabrics  

Microsoft Academic Search

Direct fiber polymer\\/antibiotic interaction is a promising means of providing infection resistance textile fabrics. Ionic interaction between cationic reactive groups (antibiotic) and carboxylic groups in wool, wool\\/polyamide, wool\\/polyester, and polyamide was used as a tool to develop desirable, durable antimicrobial fabrics.The finishing conditions such as pH, finishing temperature, and time were studied.The results revealed that pH of the finishing bath

Samiha Mohamed Abo El-Ola

2007-01-01

122

Zwitterionic hyperbranched polyester functionalized cardiovascular stent and its biocompatibility.  

PubMed

Zwitterionic hyperbranched polyester (HBPE) synthesized on bare metal stents (BMS) surface by surface-initiated atom transfer radical polymerization (SI-ATRP) method. The modified BMS obtained was tested for its blood compatibility. The blood compatibility studies were including, platelet adhesion tests, hemolysis assay, morphological changes in RBCs, coagulation tests, PRT assay, complement activation, platelet activation, and the cytotoxicity was also investigated. The modified BMS surface does not cause platelets adherent, red blood cell disruption, hemolysis and does not induce complement and platelets activation. All results indicated that the modified BMS was blood compatible and no cytotoxicity. It has the potential use for biomedical applications. PMID:24559705

Wang, Xiaobo; Miao, Jingjing; Shao, Xiaobao; Mao, Chun; Shen, Jian

2014-04-15

123

Langmuir-Blodgett Films of Supported Polyester Dendrimers  

PubMed Central

Amphiphiles with a dendritic structure are attractive materials as they combine the features of dendrimers with the self-assembling properties and interfacial behavior of water-air affinities. We have synthesized three generations of polyester dendrimers and studied their interfacial properties on the Langmuir films. The behavior obtained was, as a rule, the lowest generation dendrimers behaving like traditional amphiphiles and the larger molecules presenting complicated isotherms. The Langmuir films of these compounds have been characterized by their surface pressure versus molecular area (?/A) and Brewster angle microscopy (BAM) observations. PMID:24052855

Redón, Rocío; Carreón-Castro, M. Pilar; Mendoza-Martínez, F. J.

2012-01-01

124

Post-irradiation crosslinking of partially cured unsaturated polyester resin  

NASA Astrophysics Data System (ADS)

The post-irradiation crosslinking of unsaturated polyester (UP) resin samples irradiated to different doses was monitored during the 15-days period. The post-reaction sensitivity of three experimental techniques was evaluated. Significant changes were detected by extraction analysis that also included determination of the free styrene content. The most substantial changes were detected by differential scanning calorimetry, even up to 5 days after the irradiation. The sensitivity and reproducibility of FTIR was the lowest. The first two techniques detected the influence of particular reaction periods, at which the radiation crosslinking was terminated, on the post-reaction.

Jurkin, Tanja; Puci?, Irina

2006-09-01

125

Composite material from recycled polyester for recyclable automobile structures  

SciTech Connect

DuPont has developed a compression-moldable composite made from the thermoplastic polyester PET and long glass fibers. This material, XTC{trademark}, is part of the class of materials known as GMT`s, or glass-mat thermoplastics. The PET content in XTC{trademark} allows the use of a wide variety of recycled material that might otherwise end up in landfills and incinerators. DuPont has succeeded in using 100% post-consumer polyester, from bottles, film, or fibers, in the composite. Since processing involves heating the material to the melt in air, the main technical issues are hydrolysis and oxidative degradation. Impurities in the recycled material must be carefully monitored, as they often increase the extent of degradation. The product itself, used to mold shaped structures and body panels for automobiles, may be recycled after its useful life. Depending on the needed purity level, processes ranging from injection molding to methanolysis can turn ground XTC{trademark} parts back into new, useful products.

Lertola, J.G. [DuPont Company, Newark, DE (United States)

1995-12-31

126

[Bassini operation with polyglycolic acid or polyester. A prospective randomized study of 300 cases].  

PubMed

In a prospectively randomized trial polyglycolic acid (PGA) was tested against polyester for recurrence rate in Bassini hernia repair. After a median observation period of 2 years a distinct but statistically insignificant difference was found (12.0% recurrence for PGA against 7.0% for polyester). Within prospectively defined risk groups statistically significant differences were found for men (15.4% PGA, 6.4% polyester) and in the presence of at least one of the risk factors obesity, bronchitis, recurrent hernia, size of hernial sac greater than 8 cm, the last of which being the strongest unfavourable variable for PGA. PMID:2541981

Fuchsjäger, N; Feichter, A; Hirbawi, A; Kux, M

1989-04-01

127

Radiation-induced changes affecting polyester based polyurethane binder  

NASA Astrophysics Data System (ADS)

The application of thermoplastic polyurethane elastomers as binders in the high energy explosives particularly when used in weapons presents a significantly complex and challenging problem due to the impact of the aging of this polymer on the useful service life of the explosive. In this work, the effects of radiation on the aging of the polyester based polyurethane were investigated using both electron beam and gamma irradiation at various dose rates in the presence and absence of oxygen. It was found by means of GPC that, in the presence and absence of oxygen, the poly (ester urethane) primarily undergoes cross-linking, by means of a carbon-centered secondary alkyl radical. It was also concluded that the polymer partially undergoes scission of the backbone of the main chain at C-O, N-C, and C-C bonds. Substantial changes in the conditions of irradiation and in dose levels did not affect the cross-linking and scission yields. Experiments were also performed with EPR spectroscopy for the purpose of identifying the initial carbon-centered free radicals and for studying the decay mechanisms of these radicals. It was found that the carbon-centered radical which is produced via C-C scission (primary alkyl radical) is rapidly converted to a long-lived allylic species at higher temperatures; more than 80% radicals are converted to allyl species in 2.5 hours. In the presence of oxygen, the allyl radical undergoes a fast reaction to produce a peroxyl radical; this radical decays with a 1.7 hour half-life by pseudo first-order kinetics to negligible levels in 13 hours. FTIR measurements were conducted to identify the radiation-induced changes to the functional groups in the polyester polyurethane. These measurements show an increase in carbonyl, amine and carboxylic groups as a result of reaction of H atoms with R-C-O·, ·NH-R and R-COO·. The FTIR results also demonstrate the production of the unsaturation resulting from hydrogen atom transfer during intrachain conversion of the primary alkyl radical to the allyl species, prompt trans-vinylene production in tetramethylene units, and hydrogen atom abstraction by alkyl radicals on neighboring chains. The production of unsaturation is substantiated by the EPR studies. Finally, a free radical mechanism is proposed for the production of cross-linking in polyester polyurethane.

Pierpoint, Sujita Basi

128

Biodegradable polyesters containing ibuprofen and naproxen as pendant groups  

PubMed Central

Controlled release of non-steroidal anti-inflammatory drugs such as ibuprofen and naproxen could be beneficial for the treatment of inflammatory diseases while reducing the side effects resulting from their continuous use. Novel biodegradable polyesters solely comprised of biocompatible components (e.g., tartaric acid, 1,8-octanediol, and ibuprofen or naproxen as pendant groups) have been synthesized using tin (II) 2-ethylhexanoate as catalyst at 130 °C and subsequently characterized to determine their structures and physicochemical properties. The polymers release the free drug (ibuprofen or naproxen) in vitro in a controlled manner without burst release, unlike the release rates achieved when the drugs are encapsulated in other polymers. These new biomaterials are not cytotoxic towards mouse fibroblasts up to 0.10 mg/mL. The drugs retain their chemical structure following hydrolytic degradation of the polymer, suggesting that bioactivity is preserved. PMID:23957612

Rosario-Meléndez, Roselin; Yu, Weiling; Uhrich, Kathryn E.

2013-01-01

129

Shear properties of reinforced polyester concrete using recycled PET  

SciTech Connect

Previous research on the shear behavior of steel-reinforced polymer concrete (PC) beams has been very limited and no efficient design procedures have been proposed. In all the previous studies, it was generally assumed that the shear behavior of steel-reinforced PC is similar to the shear behavior of steel-reinforced PC is similar to the shear behavior of steel-reinforced portland cement concrete because both are composite materials consisting of a binder and inorganic aggregates. The objective of this paper is to study the behavior and to develop a design procedure in shear for steel-reinforced PC beams using unsaturated polyester resins based on recycled poly(ethylene terephthalate), PET.

Rebeiz, K.S. [Lafayette Coll., Easton, PA (United States). Dept. of Civil and Environmental Engineering; Serhal, S.P. [Cedar Corp., Adonis (Lebanon); Fowler, D.W. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering

1994-12-31

130

Interface and dynamic indentation of crosslinked polyester films  

NASA Astrophysics Data System (ADS)

The nanoindentation technique has drawn much interest recently for both its efficiency and versatility in measuring the mechanical properties of small volumes of materials and thin films. Since the unloading curve of polymers depends not only on the holding time but also on the unloading rate Hysitron Nanoindenter was used in our investigation of contact deformation of surfaces of polyester and polycarbonate supported on an aluminum substrate. Crosslinked polyesters with different gel concentration were produced on aluminum surfaces. Inter-phase plays a crucial role in composites. Stiffening and strengthening rely on load transfer across the interface, toughness is influenced by crack deflection/fiber pull-out, and ductility is affected by relaxation of peak stresses near the interface. Instead of strain softening with indentation depth observed in linear polymers, cross-linked polymers showed strain hardening. The extent of diffusion determines the extent of the interfacial region with the conformation loss of large molecules being higher than that of small molecules. Besides, considering the strain-hardening.an increasing stress is required to produce further plastic deformation after the material is strained beyond the yielding point, it is possible to separate the plastic deformation and the visco-elastic deformation and study them individually. Steady state deformation is compared with sinusoidal deformation relatable to differences in Tg from confinement effects. In cross-linked polymers, surface deformation is analyzed a three-layer model consisting of free surface layer, intermediate layer, and interface layer. Molecular relaxation dependence on molecular weight and cross-link density is shown.

Ahuja, Suresh

2008-03-01

131

Semi-aromatic polyesters based on a carbohydrate-derived rigid diol for engineering plastics.  

PubMed

New carbohydrate-based polyesters were prepared from isoidide-2,5-dimethanol (extended isoidide, XII) through melt polymerization with dimethyl esters of terephthalic acid (TA) and furan-2,5-dicarboxylic acid (FDCA), yielding semi-crystalline prepolymers. Subsequent solid-state post-condensation (SSPC) gave high molecular weight (Mn =30?kg?mol(-1) for FDCA) materials, the first examples of high Mn , semi-aromatic homopolyesters containing isohexide derivatives obtained via industrially relevant procedures. NMR spectroscopy showed that the stereo-configuration of XII was preserved under the applied conditions. The polyesters are thermally stable up to 380?°C. The TA- and FDCA-based polyesters have high Tg (105?°C and 94?°C, resp.) and Tm (284?°C and 250?°C, resp.) values. Its reactivity, stability, and ability to afford high Tg and Tm polyesters make XII a promising diol for the synthesis of engineering polymers. PMID:25382180

Wu, Jing; Eduard, Pieter; Thiyagarajan, Shanmugam; Noordover, Bart A J; van Es, Daan S; Koning, Cor E

2015-01-01

132

Sorption properties of the interfacial layer in polyester-polysiloxane block copolymers (inverse gas chromatography)  

NASA Astrophysics Data System (ADS)

The fine supramolecular structure of multiblock polyester-polysiloxane copolymers has been studied. A method is proposed for quantitatively estimating the sorption properties of interfacial layers in block copolymers, which are difficult to determine.

Kalinin, A. V.; Voznyakovski?, A. P.

2009-11-01

133

Synthesis and characterization of 1,3-bis(2-hydroxyethoxy) benzene based saturated and unsaturated polyesters  

Microsoft Academic Search

Polyesterification of adipic acid and maleic anhydride with 1,3-bis(2-hydroxyethoxy)benzene (HER) in the presence of toluene-4-sulphonic acid was carried out using melt condensation technique. The structural characterization of the synthesized polyesters had been carried out using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopic methods. The thermal properties of the polyesters were studied using differential thermal analysis

Chinnaswamy Thangavel Vijayakumar; Palanichamy Sivasamy; Thangamani Rajkumar

2007-01-01

134

Characterization of Some Modified Unsaturated Polyesters for Inhibition of Double-base Rocket Propellants  

Microsoft Academic Search

Properties of a flexible unsaturated polyester (EP4), consisting of poly(ethylene glycol), isophthalic acid, maleic anhydride, and styrene, and a less flexible unsaturated polyester (FUP-9), consisting of poly(ethylene glycol), diethylene glycol, isophthalic acid, maleic anhydride, and styrene, have been studied with varying styrene monomer ratios and partial replacement aliphatic\\/aromatic cross-linking monomers. The effect of the addition of fillers, in terms of

J. P. Agrawal; R. R. Samudra; N. T. Agawane

2001-01-01

135

Polyester-Based (Bio)degradable Polymers as Environmentally Friendly Materials for Sustainable Development  

PubMed Central

This review focuses on the polyesters such as polylactide and polyhydroxyalkonoates, as well as polyamides produced from renewable resources, which are currently among the most promising (bio)degradable polymers. Synthetic pathways, favourable properties and utilisation (most important applications) of these attractive polymer families are outlined. Environmental impact and in particular (bio)degradation of aliphatic polyesters, polyamides and related copolymer structures are described in view of the potential applications in various fields. PMID:25551604

Rydz, Joanna; Sikorska, Wanda; Kyulavska, Mariya; Christova, Darinka

2014-01-01

136

Ambient temperature catalyst-free light-induced preparation of macrocyclic aliphatic polyesters.  

PubMed

The light induced, catalyst-free ambient temperature preparation of macrocyclic aliphatic polyesters is pioneered. Based on the photo-induced Diels-Alder reaction of orthoquinodimethane and acrylate moieties, cyclic polyesters of high purity are readily synthesized. Considering the high tolerance to functional groups and the orthogonality of the ligation, the reported protocol can be easily transferred to a large range of polymers, complex topologies (tadpole, sun-shaped, jellyfish, etc.) and applications. PMID:24413149

Josse, Thomas; Altintas, Ozcan; Oehlenschlaeger, Kim K; Dubois, Philippe; Gerbaux, Pascal; Coulembier, Olivier; Barner-Kowollik, Christopher

2014-02-25

137

Visualisation of fingermarks and grab impressions on dark fabrics using silver vacuum metal deposition.  

PubMed

Vacuum metal deposition (VMD) involves the thermal evaporation of metal (silver) in a vacuum, resulting in a uniform layer being deposited on the specimen being treated. This paper examines the use of silver on dark fabrics, thus offering a simpler operation and more obvious colouration to that of the traditional use of gold and zinc metals which must be evaporated separately. The aim of this study was to investigate the effect of fabric type, donor, mark age and method of fingermark deposition on the quality of marks visualised using silver VMD. This was achieved by collecting fingermark deposits from fifteen donors, of both sexes and various ages, by a grab or a press method. Four different fabrics: satin, polyester, polycotton and cotton were studied over a 10day timeline of 1, 2, 3, 4, 5, 6, 7, 14, 21 and 28+ days. It was found that satin and polyester gave the most positive results, with polyester often producing excellent ridge detail. Cotton and polycotton were less successful with no ridge detail being observed. The donors also had an observable effect on the results obtained probably due to variations in secretions produced or pressures applied during specimen collection. The age of the mark or the method of mark deposition had little influence on the results obtained. Silver VMD is a viable process for visualising marks on certain dark fabrics and has the advantage over gold/zinc VMD in that the marks visualised are light in colour which contrasts well against the dark background. PMID:23937939

Knighting, Susan; Fraser, Joanna; Sturrock, Keith; Deacon, Paul; Bleay, Stephen; Bremner, David H

2013-09-01

138

Characterization of the Degradation Mechanisms of Lysine-derived Aliphatic Poly(ester urethane) Scaffolds  

PubMed Central

Characterization of the degradation mechanism of polymeric scaffolds and delivery systems for regenerative medicine is essential to assess their clinical applicability. Key performance criteria include induction of a minimal, transient inflammatory response and controlled degradation to soluble non-cytotoxic breakdown products that are cleared from the body by physiological processes. Scaffolds fabricated from biodegradable poly(ester urethane)s (PEURs) undergo controlled degradation to non-cytotoxic breakdown products and support the ingrowth of new tissue in preclinical models of tissue regeneration. While previous studies have shown that PEUR scaffolds prepared from lysine-derived polyisocyanates degrade faster under in vivo compared to in vitro conditions, the degradation mechanism is not well understood. In this study, we have shown that PEUR scaffolds prepared from lysine triisocyanate (LTI) or a trimer of hexamethylene diisocyanate (HDIt) undergo hydrolytic, esterolytic, and oxidative degradation. Hydrolysis of ester bonds to yield ?-hydroxy acids is the dominant mechanism in buffer, and esterolytic media modestly increase the degradation rate. While HDIt scaffolds show a modest (<20%) increase in degradation rate in oxidative medium, LTI scaffolds degrade six times faster in oxidative medium. Furthermore, the in vitro rate of degradation of LTI scaffolds in oxidative medium approximates the in vivo rate in rat excisional wounds, and histological sections show macrophages expressing myeloperoxidase at the material surface. While recent preclinical studies have underscored the potential of injectable PEUR scaffolds and delivery systems for tissue regeneration, this promising class of biomaterials has a limited regulatory history. Elucidation of the macrophage-mediated oxidative mechanism by which LTI scaffolds degrade in vivo provides key insights into the ultimate fate of these materials when injected into the body. PMID:20864156

Hafeman, Andrea E.; Zienkiewicz, Katarzyna J.; Zachman, Angela L.; Sung, Hak-Joon; Nanney, Lillian B.; Davidson, Jeffrey M.; Guelcher, Scott A.

2010-01-01

139

Antimicrobial hyperbranched poly(ester amide)/polyaniline nanofiber modified montmorillonite nanocomposites.  

PubMed

There has been growing interest in the use of nanomaterials featuring potent of antimicrobial activity in the biomedical domain. It still remains a challenge for the researchers to develop an efficient nanocomposite possessing antimicrobial efficacy against broad spectrum microbes including bacteria, fungi as well as algal consortium, posing serious challenges for the human survival. In addressing the above problem, we report the fabrication of bio-based hyperbranched poly(ester amide) (HBPEA)/polyaniline nanofiber modified montmorillonite (MMT) nanocomposites by an ex-situ polymerization technique at varied weight percentages (1, 2.5, 5 wt.%) of the modified MMT (nanohybrid). The Fourier transform infrared spectroscopy confirmed the structural changes upon interaction of the nanohybrid with HBPEA. A probable mechanism is proposed for the formation of nanocomposites with partially exfoliated nanoplatelet structure, which was further confirmed from the high resolution transmission electron microscopic analyses. The prepared nanocomposites exhibited potent efficacy against gram positive bacteria like Bacillus subtilis and Staphylococcus aureus as compared to the gram negative ones like Pseudomonas aeruginosa and Escherichia coli. The nanocomposites showed significant antifungal activity against Aspergillus niger, Fusarium oxysporum and Coleotricum capcii and antialgal activity against algal consortium comprising of Chlorella, Hormidium and Cladophorella species. The formation of thermosetting nanocomposites resulted in the acceptable improvement of desired physico-chemical and mechanical properties including thermostability. Thus pronounced antimicrobial activity of the nanocomposites against a spectrum of bacterial and fungal strains as well as a consortium of algal species along with other desired performance vouched them as potent antimicrobial materials in the realm of health and biomedical industry. PMID:24411352

Pramanik, Sujata; Bharali, Pranjal; Konwar, B K; Karak, Niranjan

2014-02-01

140

Quantification of perchloroethylene residues in dry-cleaned fabrics.  

PubMed

We have used a novel gas chromatography/mass spectrometry (GC/MS)-based approach to quantify perchloroethylene (PCE) residues in dry-cleaned fabrics. Residual PCE was extracted from fabric samples with methanol and concentration was calculated by the gas chromatographic peak area, standardized using PCE calibration data. Extracts examined were from samples of 100% wool, polyester, cotton, or silk, which were dry cleaned from one to six times in seven different Northern Virginia dry-cleaning establishments. Additional experiments were conducted to investigate the kinetics of PCE release in the extraction solvent and to the open air. We found that polyester, cotton, and wool retained ??µM levels of PCE, that these levels increased in successive dry-cleaning cycles, and that PCE is slowly volatilized from these fabrics under ambient room air conditions. We found that silk does not retain appreciable PCE. Measured differences across dry-cleaning establishments and fabric type suggest more vigorous monitoring of PCE residues may be warranted. Environ. Toxicol. Chem. 2011;30:2481-2487. © 2011 SETAC. PMID:21898565

Sherlach, Katy S; Gorka, Alexander P; Dantzler, Alexa; Roepe, Paul D

2011-11-01

141

Fungal Communities Associated with Degradation of Polyester Polyurethane in Soil?  

PubMed Central

Soil fungal communities involved in the biodegradation of polyester polyurethane (PU) were investigated. PU coupons were buried in two sandy loam soils with different levels of organic carbon: one was acidic (pH 5.5), and the other was more neutral (pH 6.7). After 5 months of burial, the fungal communities on the surface of the PU were compared with the native soil communities using culture-based and molecular techniques. Putative PU-degrading fungi were common in both soils, as <45% of the fungal colonies cleared the colloidal PU dispersion Impranil on solid medium. Denaturing gradient gel electrophoresis showed that fungal communities on the PU were less diverse than in the soil, and only a few species in the PU communities were detectable in the soil, indicating that only a small subset of the soil fungal communities colonized the PU. Soil type influenced the composition of the PU fungal communities. Geomyces pannorum and a Phoma sp. were the dominant species recovered by culturing from the PU buried in the acidic and neutral soils, respectively. Both fungi degraded Impranil and represented >80% of cultivable colonies from each plastic. However, PU was highly susceptible to degradation in both soils, losing up to 95% of its tensile strength. Therefore, different fungi are associated with PU degradation in different soils but the physical process is independent of soil type. PMID:17660302

Cosgrove, Lee; McGeechan, Paula L.; Robson, Geoff D.; Handley, Pauline S.

2007-01-01

142

Occupational contact allergy to unsaturated polyester resin cements.  

PubMed

6 men contracted occupational allergic contact dermatitis from unsaturated polyester (UP) cements. 4 of the men were employed in car repair painting and the remaining 2 in mold manufacturing. The exposure time to UP cements ranged from 6 to 32 years before onset of skin symptoms. All patients had eczema on their hands; in addition, 4 had skin symptoms on airborne areas, i.e., wrists, neck and face. All 6 patients developed allergic reactions when patch tested with UP resin at 0.5-10% in petrolatum (pet.). None of the tested patients reacted to auxiliary or cross-linking chemicals of the cements. Diethylene glycol maleate (DGM) was purified and identified from the UP resin of a cement. 1 patient reacting to UP resin was also patch test positive to DGM and he produced an allergic reaction to DGM down to a concentration of 0.0032% pet. DGM was found in both uncured and cured UP resin. None of the patients could continue their work with UP cements after their sensitization. PMID:8508632

Tarvainen, K; Jolanki, R; Estlander, T

1993-04-01

143

Fabric Architecture  

NSDL National Science Digital Library

Published by the Industrial Fabrics Association International, Fabric Architecture magazine is published bimonthly and is distributed to over 13000 architects working in the field. For those who've never thought about the possibilities and opportunities afforded by this area that straddles the lines between fabrics, design, and architecture, it's quite a find. On this page, users can look through materials that address topics like tents, lightweight structures, graphics, awnings, and truck covers. After perusing these areas, visitors should delve into the current issue. The archives here date back to 2006, and the topics covered within these pages include fabrics in the workplace, flexible design materials, and creating a "green" car park with various fabrics. For those who are interested, there's also information about how to subscribe to the print edition of the magazine.

144

Mechanical performance of hybrid polyester composites reinforced Cloisite 30B and kenaf fibre  

NASA Astrophysics Data System (ADS)

Hybridization of rubber toughened polyester-kenaf nanocomposite was prepared by adding various percentage of kenaf fiber with 4% Cloisite 30B in unsaturated polyester resin. Composite were prepared by adding filler to modified polyester resin subsequently cross-linked using methyl ethyl ketone peroxide and the accelerator cobalt octanoate 1%. Three per hundred rubbers (phr) of liquid natural rubber (LNR) were added in producing this composite. This composite expected to be applied in the interior of passenger cars and truck cabins. This is a quality local product from a combination of good properties polyester and high performance natural fiber, kenaf that is suitable for many applications such as in automotive sector and construction sector. The mechanical and thermal properties of composite were characterized using Durometer Shore-D hardness test, Izod impact test, Scanning electron microscopy, thermogravimetry (TGA) and differential scanning calorimetry (DSC). Result shows that addition of LNR give good properties on impact, flexural and hardness compare to without LNR composite. DSC curve shows that all composition of composites is fully cured and good in thermal properties. Addition of higher percentage of kenaf will lead the composite to elastic behavior and decrease the toughened properties of the composite. Hybrid system composite showed the flexural properties within the flexural properties of kenaf - polyester and Cloisite 30B.

Bonnia, N. N.; Surip, S. N.; Ratim, S.; Mahat, M. M.

2012-06-01

145

Formation of Hydrophobic and Water-Repellent Surface on Polyester Fibers using Ar\\/Hexamethyldisiloxane Plasma at Atmosperic Pressure  

Microsoft Academic Search

In this study, surface modification of polyester fibers with high water repellency was obtained by plasma treatment. Polyester fibers with water repellency were treated with atmospheric pressure middle-frequency (MF) plasma system using Ar and hexamethyldisiloxane (HMDSO). Ar gas has been used as the carrier gas. The surface morphologies of plasma-treated fibers were characterized by scanning electron microscopy (SEM). The Fourier

Young Yeon Ji; Hong Ki Chang; Yong Cheol Hong; Suck Hyun Lee

2008-01-01

146

Solid-State 13C NMR of Liquid Crystalline Polyesters: Variations in Morphology, Alignment, and Dynamics within a Homologous Series  

E-print Network

Solid-State 13C NMR of Liquid Crystalline Polyesters: Variations in Morphology, Alignment polymers was retained into the solid state if their quenchings occur while remaining within the strong NMR, the structures of these polyesters were examined by high-resolution solid-state 13C NMR. It was found that while

Frydman, Lucio

147

Deposition and localization of lipid polyester in developing seeds of Brassica napus and Arabidopsis thaliana.  

PubMed

Mature seeds of Arabidopsis thaliana and Brassica napus contain complex mixtures of aliphatic monomers derived from non-extractable lipid polyesters. Most of the monomers are deposited in the seed coat, and their compositions suggest the presence of both cutin and suberin layers. The location of these polyesters within the seed coat, and their contributions to permeability of the seed coat and other functional properties are unknown. Polyester deposition was followed over Brassica seed development and distinct temporal patterns of monomer accumulation were observed. Octadecadiene-1,18-dioate, the major leaf cutin monomer, was transiently deposited. In contrast, the saturated dicarboxylates maintained a constant level during seed desiccation, whereas the fatty alcohols and saturated omega-hydroxy fatty acids continually increased. Dissection and analysis of Brassica seed coats showed that suberization is not specific to the chalaza. Analysis of the Arabidopsis ap2-7 mutant suggested that suberin monomers are preferentially associated with the outer integument. Several Arabidopsis knockout mutant lines for genes involved in polyester biosynthesis (att1, fatB and gpat5) were examined for seed monomer load and composition. The variance in polyester monomers of these mutants is correlated with dye penetration assays. Furthermore, stable transgenic plants expressing promoter::YFP fusions showed ATT1 promoter activity in the inner integument, whereas GPAT5 promoter is active in the outer integument. Together, the Arabidopsis data indicated that there is a suberized layer associated with the outer integument and a cutin-like polyester layer associated with the inner seed coat. PMID:18179651

Molina, Isabel; Ohlrogge, John B; Pollard, Mike

2008-02-01

148

Fabric Test  

NSDL National Science Digital Library

In this classroom activity, students work in groups to test a variety of fabrics to determine each one's effectiveness as an insulator. The printable five-page handout includes a series of inquiry-based questions to get students thinking about the conditions in Antarctica and the properties of specialty fabrics, illustrated activity directions and a worksheet that includes areas for recording their experiment data, and questions that prompt students to compare their results against their original hypotheses.

149

Thermal degradation of polyester coating powders: 1,4-dicyanobenzene as an occupational marker compound.  

PubMed

A method for the determination of emissions in workroom air as a result of the thermal degradation of polyester coating powders is described. The method is based on the determination of certain marker compounds only. Polyester coating powders were degraded thermally in laboratory experiments and 1,4-dicyanobenzene was chosen as the marker compound. An air sampling method and a high-performance liquid chromatographic method for the determination of the marker compound are proposed. The detection limit for a 48-I air sample was 0.4 microgram m-3. PMID:2610363

Pukkila, J; Kokotti, H; Peltonen, K

1989-09-01

150

Surface activity of new invertible amphiphilic polyesters based on poly(ethylene glycol) and aliphatic dicarboxylic acids.  

PubMed

The surface active properties of aqueous solutions of invertible amphiphilic alternated polyesters differing by hydrophilic-lipophilic balance (HLB) and molecular weight have been determined over the wide concentration range. The polyesters are based on poly(ethylene glycol) (PEG) of two molecular weights and aliphatic dicarboxylic acids (decanedioic and dodecanedioic). The surface activity of the polyesters and their ability to form micellar assemblies (which was recently shown for organic solvents) has been confirmed in water. The central role of the balance of hydrophilic to hydrophobic groups ratio in the formation of polymeric arrangements having hydrophobic pockets and external hydrophilic shell has been shown. The effect of molecular weight has been found considerable as well. Two changes in slope have been observed for the more hydrophobic polyesters in the surface tension vs log concentration curve. The change at low concentration is believed to originate from the formation of polyester assemblies with a hydrophobic interior and hydrophilic exterior due to the interaction of hydrophobic fragments and macromolecular flexibility. The higher concentration region exhibits behavior consistent with a cmc, which was confirmed by additional dye solubilization experiments. Molecular structure of the polyester micelles is determined by the solubilization of a solvatochromic dye. The experiment confirmed that micellization of polyesters is accompanied by the association of more hydrophobic (aliphatic) constituents forming the micelle interior. The hydrophilic fragments (ethylene oxide groups) are involved in the formation of micelle exterior. PMID:18501919

Voronov, A; Vasylyev, S; Kohut, A; Peukert, W

2008-07-15

151

Viscosity change of unsaturated polyester–alumina-composites using polyethylene glycol alkyl ether based dispersants  

Microsoft Academic Search

The influence of a series of polyethylene glycol alkyl ether based dispersants on the viscosity of unsaturated polyester–alumina-composites has been investigated systematically. A few correlations between the dispersants molecular structure, the used concentration and the related composite flow properties have been found. In general only the addition of small dispersant molecules with a short hydrophilic anchoring group and an extended

T. Hanemann

2006-01-01

152

Dipeptide-based Polyphosphazene and Polyester Blends for Bone Tissue Engineering  

PubMed Central

Polyphosphazene-polyester blends are attractive materials for bone tissue engineering applications due to their controllable degradation pattern with non-toxic and neutral pH degradation products. In our ongoing quest for an ideal completely miscible polyphosphazene-polyester blend system, we report synthesis and characterization of a mixed-substituent biodegradable polyphosphazene poly[(glycine ethyl glycinato)1(phenyl phenoxy)1phosphazene] (PNGEG/PhPh) and its blends with a polyester. Two dipeptide-based blends namely 25:75 (Matrix1) and 50:50 (Matrix2) were produced at two different weight ratios of PNGEG/PhPh to poly(lactic acid-glycolic acid) (PLAGA). Blend miscibility was confirmed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Both blends resulted in higher tensile modulus and strength than the polyester. The blends showed a degradation rate in the order of Matrix2 < Matrix1 < PLAGA in phosphate buffered saline at 37°C over 12 weeks. Significantly higher pH values of degradation media were observed for blends compared to PLAGA confirming the neutralization of PLAGA acidic degradation by polyphosphazene hydrolysis products. The blend components PLAGA and polyphosphazene exhibited a similar degradation pattern as characterized by the molecular weight loss. Furthermore, blends demonstrated significantly higher osteoblast growth rates compared to PLAGA while maintaining osteoblast phenotype over a 21-day culture. Both blends demonstrated improved biocompatibility in a rat subcutaneous implantation model compared to PLAGA over 12 weeks. PMID:20334909

Deng, Meng; Nair, Lakshmi S.; Nukavarapu, Syam P.; Jiang, Tao; Kanner, William A.; Li, Xudong; Kumbar, Sangamesh G.; Weikel, Arlin L.; Krogman, Nicholas R.; Allcock, Harry R.; Laurencin, Cato T.

2010-01-01

153

THERMAL INSULATION PROPERTIES OF NONWOVEN SEMI-DISPOSABLE BLANKETS FROM RECYCLED POLYESTER/COTTON FIBERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Recycled polyester fibers and cotton fibers that require no chemical processing were used to produce a low-cost, semi-durable, nonwoven thermal blanket. Thermal blankets were given carboxylic acid finish to improve structural stability during use and laundering. A Steady-State Heat Flow meter FOX ...

154

Reactive processing of biodegradable polyesters with dicumyl peroxide: A structural, rheological and property study  

Microsoft Academic Search

Studies were undertaken to gain an understanding as to the mechanistic, rheological, thermal, and mechanical property effects that can be expected by reactively extruding biodegradable polyesters with dicumyl peroxide (DCP). The two main polymers used were poly(epsilon-caprolactone), (PCL), and proprietary copolyester, Eastar 14766. The reactive extrusions were carried out at 160°C at various DCP levels. The percent branching and type

Philip Louis Canale

1999-01-01

155

P Paper securely held in durable polyester bag for efficient and  

E-print Network

P Paper securely held in durable polyester bag for efficient and secure retrieval P Wide variety-balanced for easy handling · Hasp design for padlock security 2-Bag Bin 36" H x 40" W x 20" D Holds 60 gallons of paper. 4-Bag Bin 35" H x 40" W x 27.5" D Holds 90 gallons of paper. #12;

Guo, Zaoyang

156

The use of unsaturated polyester resin solutions in preparing casts of the renal vessels.  

PubMed

A technique to prepare casts of the renal vessels using unsaturated polyester resin solutions is described. The dimensions, morphology and relations of the vessels are very well represented by the casts. The methods is economical and easy to apply and the casts can be used for both teaching and pathologic research. PMID:3833313

Tsikaras, P D; Hytiroglou, P M; Lazos, L M

1985-03-01

157

Compression strength of carbon, glass and Kevlar-49 fibre reinforced polyester resins  

Microsoft Academic Search

The compression behaviour of a series of polyester resins of various compositions and in different states of cure has been investigated. Their mechanical characteristics having been established, the same range of resins was then used as a matrix material for a series of composites reinforced with carbon, glass and aromatic polyamide fibres. The composites were unidirectionally reinforced, having been manufactured

M. R. Piggott; B. Harris

1980-01-01

158

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride tedlar bags  

Technology Transfer Automated Retrieval System (TEKTRAN)

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar®) bags for ...

159

Modelling and simulation of an unsaturated polyester process. Geir Stian Landsverk1  

E-print Network

for the polyesterification of maleic- and phthalic anhydride with ethylene- and 1,2-propylene glycol. The reaction scheme by the polyesterification of maleic- and phthalic anhydride with ethylene- and 1,2-propylene glycol, and is used as a case- mation. 1 #12;2 Kinetic model The synthesis of unsaturated polyester from maleic and phthalic anhydride

Foss, Bjarne A.

160

An evaluation of the polyester\\/polyethylene badge packet as an identification card  

Microsoft Academic Search

With the advent of automated photographic badge making systems and automated access control systems, the need for new badge making strategies has become evident. In order to determine the suitability of the polyester\\/polyethylene badge packet for application to both the currently widely used Polaroid (TM) photographic process and the emerging automated photographic badge making process, Sandia National Laboratories procured samples

1989-01-01

161

Electrochemical polymerisation of polypyrrole and polyaniline onto conducting textiles of polyester\\/polypyrrole  

Microsoft Academic Search

Textiles of polyester were covered with polypyrrole chemically synthesised (1). This substrate is a conductive material so electrochemical polymerisation can be performed. In this work electrochemically generated films of polypyrrole and polyaniline were obtained by this way. Electropolymerised films of polypyrrole were obtained in acetronitrile medium and an inorganic counter ion (PW12O40 3- ) was employed. Furthermore double layers of

J. Molina; A. I. del Río; J. Bonastre; F. Cases

162

Characterization of a slowly degrading biodegradable polyester-urethane for tissue engineering scaffolds.  

PubMed

The purpose of this research was to develop and characterize a novel, slowly degrading polyester-urethane. In this study, a polyester-urethane with a crystalline segment of poly((R)-3-hydroxybutyric acid)-diol linked by a diisocyanate to an amorphous segment of poly(epsilon-caprolactone-co-glycolide)-diol was synthesized. Porous and nonporous scaffolds were processed using electrospinning and solvent casting respectively. The morphology, pore size, and filament diameter of the mesh and film were characterized using scanning electron microscopy (SEM). The thermal properties were examined using differential scanning calorimetry (DSC). A degradation study was initiated to characterize the change in mechanical properties, molecular weight, and surface morphology over 12 months using tensile testing, gel permeation chromatography (GPC), and SEM respectively. Concomitantly, cell morphology and viability on these variants were investigated using fibroblasts. The mechanical test data indicated a gradual decrease in the ultimate tensile strength and strain to break while the modulus of elasticity remained stable. GPC data suggested a slow decrease in the molecular weight while SEM examination revealed changed surface morphologies. The in vitro studies implied that the novel polyester-urethane was not cytotoxic and that the mesh was a more favorable scaffold towards cell viability. The summation of these results suggests that this polyester-urethane has the potential for tissue engineering applications. PMID:17323319

Henry, Jerome A; Simonet, Marc; Pandit, Abhay; Neuenschwander, Peter

2007-09-01

163

Dielectric investigation of some woven fabrics  

NASA Astrophysics Data System (ADS)

In this paper, we have investigated the temperature dependence of dielectric properties (relative dielectric permeabilities and dielectric tangents of losses) for woven fabrics of hemp, jute, flax, cotton, polyester (PES), cotton-PES mixture, and wool. The measurements have been carried out at a temperature range from -50 to 50 °C in the electric periodic field at a frequency 1 MHz in vacuum. For the same specimens, the values of the dielectric properties have also been measured at an air temperature of 21 °C and at relative humidities of 40%, 60%, and 80%. At different frequencies from 80 kHz to 5 MHz, the dielectric properties have been measured at a relative humidity of 40% and at a temperature of 21 °C. An investigation of the dielectric properties of woven fabrics can provide a better understanding of the relation between the dielectric properties of woven fabrics and the different raw material compositions, temperatures, relative air humidities, and frequencies for specimens. Hence, this investigation helps to improve textile material properties.

Cerovic, Dragana D.; Dojcilovic, Jablan R.; Asanovic, Koviljka A.; Mihajlidi, Tatjana A.

2009-10-01

164

A blanket design, apparatus, and fabrication techniques for the mass production of multilayer insulation blankets for the Superconducting Super Collider  

Microsoft Academic Search

The multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) consists of full cryostat length assemblies of aluminized polyester film fabricated in the form of blankets and installed as blankets to the 4.5K cold mass and the 20K and 80K thermal radiation shields. Approximately 40,000 MLI blankets will be required in the 10,000 cryogenic devices comprising the SSC accelerator.

J. D. Gonczy; W. N. Boroski; R. C. Niemann; J. G. Otavka; M. K. Ruschman; C. J. Schoo

1989-01-01

165

Synthesis of functionalized poly(ester carbonate) with laminin-derived peptide for promoting neurite outgrowth of PC12 cells.  

PubMed

Maleimide-functionalized poly(ester carbonate)s are synthesized by ring-opening copolymerization of furan-maleimide functionalized trimethylene carbonate (FMTMC) with L-lactide and a subsequent retro Diels-Alder reaction. The maleimide groups on poly(ester carbonate)s are amenable to Michael addition with thiol-containing molecules such as 3-mercapto-1-propanol, 2-aminoethanethiol hydrochloride, and mercaptoacetic acid under mild conditions, enabling the formation of biodegradable materials with various functional groups (e.g., hydroxyl, amine, and carboxyl). In particular, the maleimide-functionalized poly(ester carbonate) is clicked with a laminin-derived peptide CQAASIKVAV. In vitro culture of PC12 cells shows that the maleimide-functionalized polymers, especially the CQAASIKVAV-grafted one, could support cell proliferation and neurite outgrowth. The maleimide-functionalized poly(ester carbonate)s provide a versatile platform for diverse functionalization and have comprehensive potential in biomedical engineering. PMID:24962245

Xing, Dongming; Ma, Lie; Gao, Changyou

2014-10-01

166

Magnetic fabrics  

NASA Astrophysics Data System (ADS)

Since Graham [1954; 1967] demonstrated in the 1950s and 1960s that magnetic anisotropy was a quick and non-destructive way of measuring rock fabric, magnetic fabric measurements have become increasingly prevalent in the study of earth and environmental processes (see Table 1 for definitions of magnetic terms). The accomplishments of U.S. workers over the past 4 years show that the U.S. community continues to contribute to the growth and development of the field. In addition to the more traditional anisotropy of magnetic susceptibility (AMS) measurements work is branching out to include anisotropy of remanence studies, particularly anisotropy of anhysteretic remanence (AAR) [McCabe et al, 1985] and anisotropy of isothermal remanence (AIR), since these parameters can be tied directly to the remanence-carrying grains in a rock and hence have relevance to the effects of magnetic fabric on natural remanent magnetization (NRM). Along with this shift is the realization, as a result of combining nonmagnetic observations (e.g.. scanning electron microscopy (SEM), finite strain measurements) with rock magnetic measurements (e.g.. hysteresis parameters), that magnetic mineral composition (paramagnetic and ferromagnetic) has an important control on magnetic anisotropy.

Kodama, Kenneth P.

1995-07-01

167

The effect of zinc and copper oxides and other zinc compounds as fillers on the tribological behavior of thermosetting polyester  

Microsoft Academic Search

The tribological behavior of thermosetting polyester filled with CuO, ZnO, ZnF2, and Zn(C18H35O2)2 fillers was studied. Sliding was performed in ambient atmosphere at 1.0 m s?1 between a polyester pin and a hardened tool steel disk in a pin-on-disk machine. The worn and the unworn specimen pin surfaces, zinc stearate powder, and the transfer films formed during sliding were studied

S. Bahadur; L. Zhang; J. W. Anderegg

1997-01-01

168

Multiplex lateral-flow test strips fabricated by two-dimensional shaping.  

PubMed

We have fabricated paper- and nitrocellulose-based lateral-flow devices that are shaped in two dimensions by a computer-controlled knife. The resulting star, candelabra, and other structures are spotted with multiple bioassay reagents to produce multiplex lateral-flow assays. We have also fabricated laminar composites in which porous nitrocellulose media are sandwiched between vinyl and polyester plastic films. This minimizes evaporation, protects assay surfaces from contamination and dehydration, and eliminates the need for the conventional hard plastic cassette holders that are typically used to package commercial lateral-flow diagnostic strips. The reported fabrication method is novel, low-cost, and well-suited to (i) fabrication and adoption in resource-poor areas, (ii) prototype development, (iii) high-volume manufacturing, and (iii) improving rates of operator error. PMID:20355763

Fenton, Erin M; Mascarenas, Monica R; López, Gabriel P; Sibbett, Scott S

2009-01-01

169

Mechanical and Physical Properties of Polyester Polymer Concrete Using Recycled Aggregates from Concrete Sleepers  

PubMed Central

Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior. PMID:25243213

Carrión, Francisco; Montalbán, Laura; Real, Julia I.

2014-01-01

170

Modification of unsaturated polyester resins (UP) and reinforced UP resins via plasma treatment  

NASA Astrophysics Data System (ADS)

Unsaturated polyester resins (UP) and reinforced composite unsaturated polyester resins (RCP) were made superhydrophobic by plasma assisted methods. Both CF 4-plasma-enhanced chemical vapor deposition (CF 4-PECVD) and alternative method were tested. The surfaces were characterized by water contact angle (CA) measurements and scanning electron microscopy (SEM). Water contact angle results indicated that CF 4-PECVD can significantly improve the wettability of UP surfaces, but suffer from difficulties for RCP surfaces. Alternatively, O 2 plasma followed by self-assembly of octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) was tested. It was shown that regardless of the filler percentage, O 2 plasma followed by self-assembly of OTS monolayer formation all led to superhydrophobic surfaces. The results provided a means to improve the wettability of reinforced UP resins (RCP).

Li, Guanglu; Wei, Xing; Wang, Wanjun; He, Tao; Li, Xuemei

2010-10-01

171

Mechanical and physical properties of polyester polymer concrete using recycled aggregates from concrete sleepers.  

PubMed

Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior. PMID:25243213

Carrión, Francisco; Montalbán, Laura; Real, Julia I; Real, Teresa

2014-01-01

172

Studies on Tensile Properties of Eri Silk/Polyester Blended Yarn Using Design of Experiment Methodology  

NASA Astrophysics Data System (ADS)

Eri silk is one of the four varieties of silk available in India which has excellent thermal insulation property. With a view to explore its blending possibilities with polyester, manufacturing of eri/polyester blended yarn at different blend ratio in ring spinning system has been successfully performed following drawframe blending technique. The Box and Behnken design of experiment for three variables and three levels has been used to study the influence of count of the yarn spun (Ne), twist multiplier and proportion of eri fibre in the blends on some important tensile properties of the yarns produced. The chosen level of variables remaining within the industrially acceptable limits shows that fibre character and yarn parameters are the determining factors to influence yarn tensile properties. Validity of Hamburger model for the prediction of blended yarn tenacity has also been assessed for the blended yarn produced.

Choudhuri, Prabir Kumar; Majumdar, Prabal Kumar; Sarkar, Bijon

2013-03-01

173

Volatile organics off-gassed among tobacco-exposed clothing fabrics.  

PubMed

This work evaluates the characteristics of short-term release of volatile and semi-volatile organic chemicals from clothing fabrics that are exposed to environmental tobacco smoke (ETS). Various fabrics were concurrently exposed to ETS in a controlled facility, and the chemicals off-gassed were sampled using solid phase micro-extraction coupled with GC/MS analysis. Toluene-reference concentration (TRC) was calculated for nine selected chemicals and compared. The number of chemicals identified from ETS-exposed fabrics ranged from 13 (polyester and acetate) to 32 (linen). All fabrics off-gassed formaldehyde, tetradecanoic acid and n-hexadecanoic acid, while seven out of eight fabrics emitted furfural, benzonitrile, naphthalene and decanal. Natural fibers of plant origin (cotton and linen) off-gassed higher concentrations (TRC>100 ?g/l) of chemicals that have low molecular weight (~100 or less) than did natural fibers of animal origin (wool and silk) and synthetic fibers. Conversely, wool and silk off-gassed more chemicals that are of high molecular weight (>200), such as TDA (TRC>100 ?g/l) and n-HDA (TRC>500 ?g/l), than did other fabrics. Fabric structure (for a particular material) significantly affects chemical off-gassing. Cotton typically used for polo shirt (knitted) off-gassed significantly (p<0.05) higher TRC for chemicals with molecular weight of ~100 (such as furfural) than did other cottons of woven style. The dyeing of fabric (white vs. black) had a limited effect on emission, while increasing contact time with ETS increased the intensity of chemical emissions. The mean TRC for cotton exposed for 12 min was nearly doubled than those exposed for 8min, but no difference existed for polyester. PMID:21852036

Chien, Yeh-Chung; Chang, Cheng-Ping; Liu, Zheng-Zhe

2011-10-15

174

Recovery of microorganisms on fabric materials after low water temperature washing with non-oxidizing acidic bleaching formulation by culture method.  

PubMed

The recovery of microorganisms to different fabrics was evaluated after a washing process combined with a food-grade non-oxidizing acidic formulation and low washing water temperature. Cotton, polyester and a polyester/cotton blend fabric samples were inoculated with Escherichia coli, Listeria innocua and Saccharomyces cerevisiae, then dried for 1 day. They were separately placed in a simulated fabric washer and decontaminated for 1 and 10 min with the acidic formulation at 23 °C water washing temperature. The combination of direct detecting and dilution methods was used to detect survivors on fabrics. The use of ? 0.1% acidic formulation in the washing process significantly increased the efficacy of the washing for all fabric samples. Microorganisms on the cotton and mixed fabric appeared to bind more strongly and were more resistant to the washing process. No viability was observed on the fabric swatches at 1 cfu/sample detection limit when the washing process was combined with 0.5% acidic formulation in the 10 min washing cycle. These findings can be used to increase the efficiency of sanitizing fabrics in an environmentally friendly way, for remove harmful microorganisms from them and reduce cross-contamination. PMID:25252345

Lee, Jaesung; Lopes, John A; Pascall, Melvin A

2014-09-01

175

Formulation and optimization of sucrose polyester physical properties by mixture response surface methodology  

Microsoft Academic Search

The physical properties of sucrose polyester (SPE), prepared from different composite blends of fatty acid methyl esters (FAME)\\u000a of safflower oil, palm oil, and peanut oil, were evaluated by mixture response surface methodology. Optimum combinations of\\u000a fatty, acids to achieve specific physical properties of SPE were determined. The SPE most similar in physical properties to\\u000a peanut oil was obtained with

Chwen-Jen Shieh; Casimir C. Akoh; Philip E. Koehler

1996-01-01

176

Mechanical Properties and Thermal Conductivity of Typha angustifolia Natural Fiber–Reinforced Polyester Composites  

Microsoft Academic Search

Partially biodegradable Typha angustifolia natural fiber–reinforced polyester composites were prepared. The fiber content in the composites was varied from ?18.3% to 35.5% by volume, and the mechanical properties in each case were determined. The thermal conductivity of these composites at 333 K temperature was also determined. The mechanical properties increased with increase in fiber content. Further, the density and thermal conductivity

K. Ramanaiah; A. V. Ratna Prasad; K. Hema Chandra Reddy

2011-01-01

177

Poly(Ester Amide) with Pendent 8Quinolinol Moiety as a Novel Oligomeric Ligand  

Microsoft Academic Search

The poly(ester amide) (PEA) was prepared by polycondensation of 1,4-phenylenebisphthalamic acid and the epoxy resin diglycidyl ether of bisphenol-A. The PEA was then treated with 5-chloromethyl-8-quinolinol hydrochloride. The resultant oligomer, designated as PEA-8-quinolinol (PEAQ), was characterized by elemental analysis, IR spectral studies and thermogravimetry. The metal chelates of PEAQ with Cu, Zn, Mn, Ni, and Co metal ions were prepared

Arun Singh; Jayesh Bhanderi

2008-01-01

178

Application of the long-chain linear polyester in plastification of PVC  

Microsoft Academic Search

The plastification modification of poly (vinyl chloride) (PVC) with the long-chain linear polyester (LP) synthesized by linear\\u000a dodecanedioic acid (DC12) or tetradecanedioic acid (DC14) with different diols is investigated. The processing characteristics,\\u000a mechanical properties and extraction property of the PVC\\/LP blends in different solvents (xylene, cyclohexane, ethanol) were\\u000a also studied in detail. All results were compared with that of the

Yan Li; Changming Wang; Guojian Wang; Zehua Qu

2008-01-01

179

Cycle history data and elongation characteristics for polyester and aramid wire-lay construction ropes  

Microsoft Academic Search

High performance ropes have unique properties that are derived from their fiber and construction. Wire-lay construction rope manufactured from 1W81 polyester with SeaGuard(R) finish and Kevlar(R) 29 aramid are observed in this study while experiencing 250,000+ cycles of tension-tension fatigue. The results indicate general behavioral trends. The numerical data obtained can be used in computer models to evaluate the appropriate

E. W. Huntley

1997-01-01

180

Dielectric Properties of Lead Monoxide Filled Unsaturated Polyester Based Polymer Composites  

NASA Astrophysics Data System (ADS)

Lead monoxide filled isophthalate resin particulate polymer composites were prepared with different filler concentrations and investigated for physical, thermal, mechanical and gamma radiation shielding characteristics. This paper discusses about the dielectric properties of the composites. The present study showed that the dielectric constant (?'), dielectric loss (??) and ac conductivity (?ac) of isopthalate based unsaturated polyester resin increases with the increase in wt% PbO filler in polymer matrix.

Harish, V.; Kumar, H. G. Harish; Nagaiah, N.

2011-07-01

181

Purification and Properties of a Polyester Polyurethane-Degrading Enzyme from Comamonas acidovorans TB-35  

PubMed Central

A polyester polyurethane (PUR)-degrading enzyme, PUR esterase, derived from Comamonas acidovorans TB-35, a bacterium that utilizes polyester PUR as the sole carbon source, was purified until it showed a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This enzyme was bound to the cell surface and was extracted by addition of 0.2% N,N-bis(3-d-gluconamidopropyl)deoxycholamide (deoxy-BIGCHAP). The results of gel filtration and SDS-PAGE showed that the PUR esterase was a monomer with a molecular mass of about 62,000 Da. This enzyme, which is a kind of esterase, degraded solid polyester PUR, with diethylene glycol and adipic acid released as the degradation products. The optimum pH for this enzyme was 6.5, and the optimum temperature was 45°C. PUR degradation by the PUR esterase was strongly inhibited by the addition of 0.04% deoxy-BIGCHAP. On the other hand, deoxy-BIGCHAP did not inhibit the activity when p-nitrophenyl acetate, a water-soluble compound, was used as a substrate. These observations indicated that this enzyme degrades PUR in a two-step reaction: hydrophobic adsorption to the PUR surface and hydrolysis of the ester bond of PUR. PMID:16349494

Akutsu, Yukie; Nakajima-Kambe, Toshiaki; Nomura, Nobuhiko; Nakahara, Tadaatsu

1998-01-01

182

Occupational allergic contact dermatitis to cobalt octoate included as an accelerator in a polyester resin.  

PubMed

A 46-year-old woman, who worked as a laminator of spa baths, presented with hand dermatitis, which was suspected to be related to her occupation. Patch testing revealed strong reactions to both cobalt chloride and a polyester resin that the patient had been using at her workplace. She also reacted to latex and had been wearing cotton gloves underneath rubber gloves at work. It was later discovered that cobalt octoate (synonym: cobalt-2-ethylhexanoate), a compound not listed on the manufacturer's material safety data sheet, was included as an accelerator in the polyester resin. She was then tested to cobalt octoate, which was also strongly positive. Her successful treatment included protection of her hands at work with cotton lined PVC gloves. This case highlights the role of cobalt salts as sensitizers and their presence as accelerators used in polyester resins, and the importance of recognizing concomitant latex allergy that may complicate occupational dermatitis. It also illustrates the difficulties in relying on material safety data sheets to identify all possible allergens. PMID:16637815

Anavekar, Namrata S; Nixon, Rosemary

2006-05-01

183

Conceptual design and comparison of aramid and polyester taut leg spread moorings for deepwater applications  

SciTech Connect

As the offshore industry looks beyond water depths of 3,000 ft for future oil and gas production, the industry standard steel catenary spread mooring (CSM) system used on all floating production systems installed to date becomes increasingly inefficient and costly. An alternative to the CSM is the Taut Leg Spread Mooring (TLSM) system with its characteristic short scope legs and vertically loaded anchors. In water depths greater than 3,000 ft, it has been shown that TLSMs comprised of synthetic mooring lines have performance advantages over systems utilizing steel wire rope and demonstrated potential for significant cost reductions. Early studies investigated the use of aramid fiber rope due to its high strength, lower in-water weight and lower axial stiffness as compared to ropes made from steel. Later studies indicated that the material properties of polyester fiber, primarily its lower Young`s modulus, made polyester mooring lines more suitable for use in TLSMs. As the TLSM knowledge base expanded, aramid rope construction evolved. Earlier efforts to match the characteristics of steel wire rope have given way to new generation soft aramid constructions. This paper compares the mooring performance and total installed cost of a soft aramid TLSM to a typical polyester configuration. Both systems were designed for use in the Gulf of Mexico (GOM) with an FPS based on the Aker P45.

Wilde, B.; Kelly, P.; Librino, F.; Whitehill, A.S.

1996-12-31

184

Mechanical Properties of Composites Based on Low Styrene Emission Polyester Resins for Marine Applications  

NASA Astrophysics Data System (ADS)

Glass fibre reinforced polyester composites are used extensively for hulls and decks of pleasure boats. Boat-builders must optimise manufacturing technology, not only with respect to mechanical properties but also limiting volatile organic compounds (VOC) emissions. One way to achieve this is through modified polyester resin formulations such as low styrene content, low styrene emission or combinations of these. The resin matrix selection procedure is based on design specification (mechanical behaviour) but also manufacturing requirements and cost considerations. For this application post-cure is rarely used so it is important to optimise curing conditions. In this study the influence of the curing cycle on mechanical properties was examined first for two polyester resins. Then for one cycle (16 h at 40°C) the properties of eight resins have been determined. Significant differences in failure strain are observed, from 0.9% to 3.3%. The resins with improved VOC performance are the most brittle. The transverse tensile behaviour of these resins in composites with unidirectional glass fibre reinforcement and the limit of linearity for composites with glass mat both depend on these failure strains. These results are discussed in terms of admissible composite strains for boat design.

Baley, Christophe; Perrot, Y.; Davies, Peter; Bourmaud, A.; Grohens, Yves

2006-01-01

185

A functionalizable polyester with free hydroxyl groups and tunable physiochemical and biological properties  

PubMed Central

Polyesters with free functional groups allow facile modifications with biomolecules, which can lead to versatile biomaterials that afford controlled interactions with cells and tissues. Efficient synthesis of functionalizable polyesters is still a challenge that greatly limits the availability and widespread applications of biofunctionalized synthetic polymers. Here we report a simple route to prepare a functionalizable polyester, poly(sebacoyl diglyceride) (PSeD) bearing free hydroxyl groups. The key synthetic step is an epoxide ring-opening polymerization, instead of the traditional polycondensation, that produces poly(glycerol sebacate) (PGS) [1]. PSeD has a more defined structure with mostly linear backbone, more free hydroxyl groups, higher molecular weight, and lower polydispersity than PGS. Crosslinking PSeD with sebacic acid yields a polymer five times tougher and more elastic than cured PGS. PSeD exhibits good cytocompatibility in vitro. Furthermore, functionalization by glycine proceeds with high efficiency. This versatile synthetic platform can offer a large family of biodegradable, functionalized polymers with tunable physiochemical and biological properties useful for a wide range of biomedical applications. PMID:20149441

You, Zhengwei; Cao, Haiping; Gao, Jin; Shin, Paul H.; Day, Billy W.; Wang, Yadong

2010-01-01

186

Chemical enhancement of soil based footwear impressions on fabric.  

PubMed

This study investigates the enhancement of footwear impressions prepared with soils from different locations on a variety of fabric surfaces with different morphology. Preliminary experiments using seventeen techniques were carried out and the best responding reagents were evaluated further. Results indicated that the soils investigated (a cross-section of soils from Scotland) are more likely to respond to reagents that target iron ions rather than calcium, aluminium or phosphorus ions. Furthermore, the concentration of iron and soil pH did not appear to have an effect on the performance of the enhancement techniques. For the techniques tested, colour enhancement was observed on all light coloured substrates while enhancement on dark coloured fabrics, denim and leatherette was limited due to poor contrast with the background. Of the chemical enhancement reagents tested, 2,2'-dipyridil was a suitable replacement for the more common enhancement technique using potassium thiocyanate. The main advantages are the use of less toxic and flammable solvents and improved clarity and sharpness of the enhanced impression. The surface morphology of the fabrics did not have a significant effect on the enhancement ability of the reagents apart from a slight tendency for diffusion to occur on less porous fabrics such as polyester and nylon/lycra blends. PMID:22153620

Farrugia, Kevin J; Bandey, Helen; Dawson, Lorna; Daéid, Niamh Nic

2012-06-10

187

Self-cleaning and self-sanitizing coatings on plastic fabrics: design, manufacture and performance.  

PubMed

Self-cleaning and self-sanitizing coatings are of utmost interest in several manufacturing domains. In particular, fabrics and textile materials are often pre-treated by impregnation or incorporation with antimicrobial pesticides for protection purposes against bacteria and fungi that are pathogenic for man or other animals. In this respect, the present investigation deals with the design and manufacture of self-cleaning and self-sanitizing coatings on plastic fabrics. The functionalization of the coatings was yield by incorporating active inorganic matter alone (i.e., photo-catalytic TiO2 anatase and Ag(+) ions) inside an organic inorganic hybrid binder. The achieved formulations were deposited on coextruded polyvinylchloride-polyester fabrics by air-mix spraying and left to dry at ambient temperature. The performance of the resulting coatings were characterized for their self-cleaning and self-sanitizing ability according to standardized testing procedure and/or applicable international regulations. PMID:24892563

Barletta, M; Vesco, S; Tagliaferri, V

2014-08-01

188

Synthesis, Properties and Applications of Biodegradable Polymers Derived from Diols and Dicarboxylic Acids: From Polyesters to Poly(ester amide)s  

PubMed Central

Poly(alkylene dicarboxylate)s constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and ?-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amide)s derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed. PMID:24776758

Díaz, Angélica; Katsarava, Ramaz; Puiggalí, Jordi

2014-01-01

189

The polyester rope taut leg mooring concept: A feasible means for reducing deepwater mooring cost and improving stationkeeping performance  

SciTech Connect

The polyester rope taut leg mooring system offers a unique opportunity to reduce deepwater mooring system cost, while simultaneously improving stationkeeping performance. These gains are over catenary or taut leg systems designed using all steel components. This paper builds upon work presented at prior OTC conferences and focuses on concept feasibility and implementation. Feasibility is addressed from a systems basis including fiber and rope selection, definition of mechanical properties, mooring system integration, and effects of long-term usage. Implementation is believed practical based on current technology and in-place manufacturing capability. Available cyclic tension test results for polyester rope suggest a comparable fatigue performance to wire rope. The most significant challenge facing application of the polyester taut leg mooring concept is the lack of in-service experience compared to conventional steel catenary mooring systems.

Winkler, M.M.; McKenna, H.A.

1995-12-01

190

Structural and Functional Studies of Aspergillus oryzae Cutinase: Enhanced Thermostability and Hydrolytic Activity of Synthetic Ester and Polyester Degradation  

SciTech Connect

Cutinases are responsible for hydrolysis of the protective cutin lipid polyester matrix in plants and thus have been exploited for hydrolysis of small molecule esters and polyesters. Here we explore the reactivity, stability, and structure of Aspergillus oryzae cutinase and compare it to the well-studied enzyme from Fusarium solani. Two critical differences are highlighted in the crystallographic analysis of the A. oryzae structure: (i) an additional disulfide bond and (ii) a topologically favored catalytic triad with a continuous and deep groove. These structural features of A. oryzae cutinase are proposed to result in an improved hydrolytic activity and altered substrate specificity profile, enhanced thermostability, and remarkable reactivity toward the degradation of the synthetic polyester polycaprolactone. The results presented here provide insight into engineering new cutinase-inspired biocatalysts with tailor-made properties.

Liu, Z.; Gosser, Y; Baker, P; Ravee, Y; Li, H; Butterfoss, G; Kong, X; Gross, R; Montclare, J; et al.

2009-01-01

191

Fumed silica concentration effect on structure and dielectric properties of a styrene-cross-linked unsaturated polyester resin  

NASA Astrophysics Data System (ADS)

Concentration effects of a high-reactive-surface nanosized SiO2 filler on structure and dielectrical properties of a styrene-cross-linked polyester resin have been experimentally studied. Thermal desorption mass-spectroscopy, IR-spectroscopy, dielectric spectroscopy, and positron annihilation lifetime spectroscopy were used to determine an atomic content of thermal destruction products, IR-reflection spectra, complex dielectric permittivity, and a nature of positron traps as function of filler content in the polymer matrix. Interaction between active surface centers of SiO2-nanoparticles and atoms of polyester chains and styrene molecules gives the non-monotonous influence on the structure of polyester chains, macromolecule polarity, dielectric parameters and the number of positronium nanotraps.

Gorelov, B. M.; Polovina, O. I.; Gorb, A. M.; Dacko, S.; Kostrzewa, M.; Ingram, A.

2012-11-01

192

Preparation of highly exfoliated polyester-clay nanocomposites: process-property correlations.  

PubMed

A large number of polyester nanocomposite batches featuring different kinds of nanoclay surface modifiers and up to 6 wt % nanoclay were manufactured using a solvent-based technique. Montmorillonite platelets modified with ammonium ions of different chemical architectures were examined to study the effect of ammonium ions on the extent of surface reactions with long-chain fatty acids. The ammonium montmorillonite was first dispersed and suspended in acetone. This suspension was further esterificated with dotriacontanoic (lacceroic) acid to form high density brushes on the clay surface. This led to achieving higher basal plane spacing of the montmorillonite platelets due to the reduction of electrostatic interactions holding them. The outcome of the surface esterification was analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The esterificated ammonium-modified clays were then mixed by five different mixing strategies based on the use of a three-roll mill mixer (TRM) and/or ultrasonication (US) to obtain the desired polyester-nanoclay dispersion, intercalation, and exfoliation. The dispersion states of the modified nanoclay in polymer were characterized from XRD, scanning electron microscopy (SEM), and low and high magnification transmission electron microscopy (TEM). Mechanical, thermal, and barrier properties of the resulting composites were experimentally characterized. The Mori-Tanaka method along with an orientation distribution function was used to verify the experimental effective stiffness of the polyester nanocomposite systems. The aspect ratio of nanoclays and their level of intercalation and/or exfoliation after mixing were also confirmed by the comparison of the experimental diffusivity results with those of Fick's diffusion model. Systems having 4 and 6 wt % esterificated ammonium nanoclay and prepared according to a combined TRM/US mixing procedure showed optimal performance with balanced properties and processing ease, thereby showing potential for use in the automotive, transportation, and packaging industries. PMID:22087630

Dalir, Hamid; Farahani, Rouhollah D; Nhim, Vireya; Samson, Benjamin; Lévesque, Martin; Therriault, Daniel

2012-01-10

193

Deep eutectic solvent-assisted synthesis of biodegradable polyesters with antibacterial properties.  

PubMed

Bacterial infection related to the implantation of medical devices represents a serious clinical complication, with dramatic consequences for many patients. In past decades, numerous attempts have been made to develop materials with antibacterial and/or antifouling properties by the incorporation of antibiotic and/or antiseptic compounds. In this context, deep eutectic solvents (DESs) are acquiring increasing interest not only as efficient carriers of active principle ingredients (APIs) but also as assistant platforms for the synthesis of a wide repertoire of polymer-related materials. Herein, we have successfully prepared biodegradable poly(octanediol-co-citrate) polyesters with acquired antibacterial properties by the DES-assisted incorporation of quaternary ammonium or phosphonium salts into the polymer network. In the resulting polymers, the presence of these salts (i.e., choline chloride, tetraethylammonium bromide, hexadecyltrimethylammonium bromide, and methyltriphenylphosphonium bromide) inhibits bacterial growth in the early postimplantation steps, as tested in cultures of Escherichia coli on solid agar plates. Later, positive polymer cytocompatibility is expected to support cell colonization, as anticipated from in vitro preliminary studies with L929 fibroblasts. Finally, the attractive elastic properties of these polyesters permit matching those of soft tissues such as skin. For all of these reasons, we envisage the utility of some of these antibacterial, biocompatible, and biodegradable polyesters as potential candidates for the preparation of antimicrobial wound dressings. These results further emphasize the enormous versatility of DES-assisted synthesis for the incorporation, in the synthesis step, of a wide palette of APIs into polymeric networks suitable for biomedical applications. PMID:23808373

García-Argüelles, Sara; Serrano, M Concepción; Gutiérrez, María C; Ferrer, M Luisa; Yuste, Luis; Rojo, Fernando; del Monte, Francisco

2013-07-30

194

Immobilized Candida antarctica lipase B: Hydration, stripping off and application in ring opening polyester synthesis.  

PubMed

This work reviews the stripping off, role of water molecules in activity, and flexibility of immobilized Candida antarctica lipase B (CALB). Employment of CALB in ring opening polyester synthesis emphasizing on a polylactide is discussed in detail. Execution of enzymes in place of inorganic catalysts is the most green alternative for sustainable and environment friendly synthesis of products on an industrial scale. Robust immobilization and consequently performance of enzyme is the essential objective of enzyme application in industry. Water bound to the surface of an enzyme (contact class of water molecules) is inevitable for enzyme performance; it controls enzyme dynamics via flexibility changes and has intensive influence on enzyme activity. The value of pH during immobilization of CALB plays a critical role in fixing the active conformation of an enzyme. Comprehensive selection of support and protocol can develop a robust immobilized enzyme thus enhancing its performance. Organic solvents with a log P value higher than four are more suitable for enzymatic catalysis as these solvents tend to strip away very little of the enzyme surface bound water molecules. Alternatively ionic liquid can work as a more promising reaction media. Covalent immobilization is an exclusively reliable technique to circumvent the leaching of enzymes and to enhance stability. Activated polystyrene nanoparticles can prove to be a practical and economical support for chemical immobilization of CALB. In order to reduce the E-factor for the synthesis of biodegradable polymers; enzymatic ring opening polyester synthesis (eROPS) of cyclic monomers is a more sensible route for polyester synthesis. Synergies obtained from ionic liquids and immobilized enzyme can be much effective eROPS. PMID:22041165

Idris, Ani; Bukhari, Attaullah

2012-01-01

195

Periodically clickable polyesters: study of intrachain self-segregation induced folding, crystallization, and mesophase formation.  

PubMed

A series of polyesters based on 2-propargyl-1,3-propanediol or 2,2-dipropargyl-1,3-propanediol or 2-allyl-2-propargyl-1,3-propanediol and 1,20-eicosanedioic acid were prepared by solution polycondensation using the corresponding diacid chloride; these polyesters were quantitatively "clicked" with a fluoroalkyl azide, namely CF3(CF2)7CH2CH2N3, to yield polyesters carrying long-chain alkylene segments in the backbone and either one or two perfluoroalkyl segments located at periodic intervals along the polymer chain. The immiscibility of the alkylene and fluoroalkyl segments causes the polymer chains to fold in a zigzag fashion to facilitate the segregation of these segments; the folded chains further organize in the solid state to form a lamellar structure with alternating domains of alkyl (HC) and fluoroalkyl (FC) segments. Evidence for the self-segregation is provided by DSC, SAXS, WAXS, and TEM studies; in two of the samples, the DSC thermograms showed two distinct endotherms associated with the melting of the individual domains, while the WAXS patterns confirm the existence of two separate peaks corresponding to the interchain distances within the crystalline lattices of the HC and FC domains. SAXS data, on the other hand, reveal the formation of an extended lamellar morphology with an interlamellar spacing that matches reasonably well with those estimated from TEM studies. Interestingly, a smectic-type liquid crystalline phase is observed at temperatures between the two melting transitions. These systems present a unique opportunity to develop interesting nanostructured polymeric materials with precise control over both the domain size and morphology; importantly, the domain sizes are far smaller than those typically observed in traditional block copolymers. PMID:24432739

Mandal, Joydeb; Krishna Prasad, S; Rao, D S Shankar; Ramakrishnan, S

2014-02-12

196

Curing study of orthophtalic polyester resin: Effect on the degradation in saline environment  

NASA Astrophysics Data System (ADS)

Nowadays, composite materials based on a polymeric matrix are widely used in structural applications as engineering materials which offer high performances in advanced industrial sectors such as aerospace, aeronautical, transport, construction, etc. They can provide excellent mechanical and chemical properties, good chemical and weather resistance and low cost. Unsaturated polyester is one of the most used thermoset as a matrix for glass fibre reinforcements because of its good relationship properties/cost/quality, since it allows a more competitive cost. Due to the importance that this type of materials reach in some industrial sectors, it is important the mechanical behaviour evaluation as one of the priorities in practically any of their applications; also, it is important to keep in mind that most of industrial sectors that use this resin are subjected to extreme environmental conditions that can produce degradation in the material and therefore, chemical resistance of composites becomes a critical characteristic in those applications that require a contact with environmental agents that can induce some degradation processes and, consequently, a substantial change on general performance. The present study is focussed in the analysis of the effect of curing reaction of the thermosetting matrix of unsaturated orthophtalic polyester in the long term behaviour of materials made up of this type of matrix and glass fibre reinforcement. This is to determine the optimum processing conditions and its behaviour in an aggressive environment, concretely, marine environment. Considering this, crosslinking level of the resin is a decisive parameter, since we can expect lower saline water absorption for high crosslinking levels. The optimum processing conditions are those that permit to obtain the highest crosslinking level in the unsaturated polyester internal structure. Since the degradation effect is related to the crosslinking level of the internal structure, with the optimum cured state conditions the loss of mechanical performance due to degradation is minimum, and therefore the resin shows the maximum quality to reach specifications required in its industrial service.

Sanchez Nacher, Lourdes

197

Influence of carbon nanotubes diameter on thermal conductivity of polyester based nanocomposites  

NASA Astrophysics Data System (ADS)

Carbon nanotubes (CNTs) are considered good candidates to improve the physical properties of polymeric materials. It is well known that CNTs have one of the highest thermal conductivities in nature. However, it has been found that thermal resistance between polymer matrix and CNTs, at nanometric scale, could imply a disadvantage to obtain high thermal conductivity nanocomposites. In this work, the effect of CNTs diameter on the effective thermal conductivity of composites based on polyester resin is studied. In particular, the effects of CNT's diameter and volume fraction are analyzed. The thermal conductivity of the nanocomposites is obtained determining the thermal diffusivity by photothermal radiometry and from the values of their specific heat capacity.

de Coss-Martínez, Romeo; Quiñones-Weiss, Graciela Inés; Anely Doporto-Valladares, Jazmín; Guadalupe Vales-Pinzón, Caridad; Zambrano-Arjona, Miguel Ángel; Mendez-Gamboa, José Ángel; Medina-Esquivel, Rubén Arturo; Alvarado-Gil, Juan José

2012-02-01

198

Water-extended polyester neutron shield for a 252Cf neutron source.  

PubMed

A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. During calculations, (252)Cf and shielding were modelled and the neutron spectra as well as the H(10) were calculated in four sites. The calculation was extended to include a water shielding, the source in vacuum and in air. Besides neutron shielding characteristics, the Kerma in air due to gammas emitted by (252)Cf and due to capture gamma rays in the shielding were included. PMID:17496334

Vega-Carrillo, H R; Manzanares-Acuña, E; Hernández-Dávila, V M; Gallego, E; Lorente, A; Donaire, I

2007-01-01

199

Reducing the shrinkage and setting dose in polyester resins by addition of metal oxides  

NASA Astrophysics Data System (ADS)

To an unsaturated polyester resin, metal oxides (MgO, CaO, BaO) were introduced which reacted with it for 200 h. In this modified resin cured by radiation, considerable reduction of setting dose as well as of the shrinkage of resin were observed in comparison with the unmodified resin. It has been also found that there is an addition of this effect with the previously observed antishrinking action of epoxy resin containing unsaturated bonds. 1,2 The service properties of the resin modified with metal oxides have not changed, while its thermal stability has increased.

Pietrzak, M.; Szali?ska, H.

200

Application of foams to the processing of fabrics. Phase III. Technical progress report, September 1, 1979-August 31, 1980  

SciTech Connect

Objective is to reduce the energy required to evaporate the water in wet processes by using foams. By the end of August 1980 approximately 400,000,000 yards of fabric had been foam finished. Plant energy data from three UM and M plants have been collected which shows great savings. Considerable work has been done on developing applicators to apply dye and finish uniformly to flat goods. Simultaneously tinting and foam finishing by the use of a tripad show promise. Foam dyeing of nylon carpets is in production and approximately 3 million pounds of carpet have been foam dyed in one US plant. Nylon flock fabric dyeing has been scaled-up in pilot plant and plant trials. Foam dyeing of 100% polyester blankets utilizing pigment foam and disperse dye foam is in production in one textile mill. Foam pigment dyeing of flat goods by horizontal pad application shows promise by the traverse application of foam on both sides of fabric. Wet on wet foam dyeing of prepared wet fabrics is feasible. A polyester/cotton narrow width industrial toweling is now being foam dyed and finished simultaneously commercially. Foam printing using engraved rolls continues in production.

Namboodri, C.G.

1980-09-01

201

Mechanical properties of small-diameter polyurethane vascular grafts reinforced by weft-knitted tubular fabric.  

PubMed

Polyester filament yarns of different Deniers were knitted into tubular fabrics with different densities and thicknesses on a specially designed weft-knitting machine. The developed tubular fabric was used to reinforce polyurethane vascular graft and thus a kind of composite vascular graft was fabricated with a small inner diameter of 4 mm. Tensile properties of the reinforced composite vascular grafts were compared with the control tubular fabric and the pure PU vascular grafts. Elasticity and strength of the reinforced vascular grafts were improved compared with the weft-knitted tubular fabrics. Strength of the reinforced composite vascular grafts was almost 5-10 times of the strength of the pure PU vascular grafts. As the PU content increased in the reinforced composite vascular grafts, the wall thickness of the vascular graft and its strength increased, but the initial modulus of the reinforced composite vascular grafts remained similar to that of the weft-knitted tubular fabric, and the PU content showed little influence on the initial modulus of the reinforced composite vascular grafts. Microporous structure can also be fabricated in the wall of the reinforced composite vascular grafts. PMID:19165779

Xu, Weilin; Zhou, Fei; Ouyang, Chenxi; Ye, Wenxiang; Yao, Mu; Xu, Bugao

2010-01-01

202

Metal/PET Composite Knitted Fabrics and Composites: Structural Design and Electromagnetic Shielding Effectiveness  

NASA Astrophysics Data System (ADS)

Following rapid technological advances, electronic products are being used more frequently than ever, resulting in a massive amount of interference from electromagnetic waves. In this research, stainless-steel (SS) wires, copper wires, and polyester (PET) filaments were made into SS/PET, copper/PET, and SS/copper/PET composite ply yarns. These ply yarns were then knitted into electromagnetic shielding fabrics with various knitting-needle densities. In the frequency range of 1.1 GHz to 1.4 GHz, the electromagnetic shielding effectiveness (EMSE) of the SS/PET fabric was 3.8 dB greater than that of the copper/PET composite knitted fabric, demonstrating better permeability. However, in the frequency range of 0.36 GHz to 1.1 GHz, the EMSE of the copper/PET fabric was 10 dB greater than that of the SS/PET fabric, demonstrating better conductivity. The SS/copper/PET fabrics exhibited an EMSE 10 dB greater than that of the SS/PET or copper/PET fabrics.

Huang, Chen-Hung; Lin, Jia-Horng; Yang, Ruey-Bin; Lin, Ching-Wen; Lou, Ching-Wen

2012-08-01

203

Strength properties of polyester mortar using PET and fly ash wastes  

SciTech Connect

The effect of sand and fly ash on the strength properties of polyester mortar (PM) using unsaturated polyester resins based on recycled poly(ethylene terephthalate) (PET) plastic waste have been evaluated in this study. Useful equations were also developed to predict the strength and modulus of PM using various amounts of sand and fly ash fillers individually as well as a combination of both. This evaluation is important not only from the standpoint that waste materials are being used, but also because no information is available in this area with PM using virgin materials. The test results show that the use of fly ash and PET wastes is very beneficial for the production of good-quality and relatively low-cost PM. In addition, the utilization of these wastes in PM would help save energy and alleviate an environmental problem. The PM could be utilized in a variety of construction applications such as the overlay of pavements, dams, and industrial floors, or as an adhesive to bond materials of similar or dissimilar compositions.

Rebeiz, K.S.; Rosett, J.W.; Craft, A.P. [Lafayette Coll., Easton, PA (United States)

1996-04-01

204

High T(g) bio-based aliphatic polyesters from bicyclic D-mannitol.  

PubMed

The carbohydrate-based diol 2,4:3,5-di-O-methylene-d-mannitol (Manx) has been used to obtain aliphatic polyesters. Manx is a symmetric bicyclic compound consisting of two fused 1,3-dioxane rings and bearing two primary hydroxyl groups. In terms of stiffness, it is comparable to the widely known isosorbide, but it affords the additional advantages of being much more reactive in polycondensation and capable of producing stereoregular polymers with fairly high molecular weights. A fully bio-based homopolyester (PManxS) has been synthesized by polycondensation in the melt from dimethyl succinate and Manx. The high thermal stability of PManxS, its relatively high glass transition temperature (Tg = 68 °C) and elastic modulus, and its enhanced sensitivity to the action of lipases point to PManxS as a polyester of exceptional interest for those applications where biodegradability and molecular stiffness are priority requirements. In addition, random copolyesters (PBxManxyS) covering a broad range of compositions have been obtained using mixtures of Manx and 1,4-butanediol in the reaction with dimethyl succinate. All PBxManxyS were semicrystalline and displayed Tg values from -29 to +51 °C steadily increasing with the content in Manx units. The stress-strain behavior of these copolyesters largely depended on their content in Manx and they were enzymatically degraded faster than PBS. PMID:23363397

Lavilla, Cristina; Alla, Abdelilah; Martínez de Ilarduya, Antxon; Muñoz-Guerra, Sebastián

2013-03-11

205

Preparation and ageing-resistant properties of polyester composites modified with functional nanoscale additives  

PubMed Central

This study investigated ageing-resistant properties of carboxyl-terminated polyester (polyethylene glycol terephthalate) composites modified with nanoscale titanium dioxide particles (nano-TiO2). The nano-TiO2 was pretreated by a dry coating method, with aluminate coupling agent as a functional grafting additive. The agglomeration resistance was evaluated, which exhibited significant improvement for the modified nanoparticles. Then, the effects of the modified nano-TiO2 on the crosslinking and ageing-resistant properties of the composites were studied. With a real-time Fourier transform infrared (FT-IR) measurement, the nano-TiO2 displayed promoting effect on the crosslinking of polyester resin with triglycidyl isocyanurate (TGIC) as crosslinking agent. Moreover, the gloss retention, colour aberration and the surface morphologies of the composites during accelerated UV ageing (1500 hours) were investigated. The results demonstrated much less degree of ageing degradation for the nanocomposites, indicating an important role of the nano-TiO2 in improving the ageing-resistant properties of synthetic polymer composites. PMID:24872802

2014-01-01

206

Preparation and thermal-mechanical characterization of nanoclay-unsaturated polyester composites.  

PubMed

Recently polymer nanocomposites have attracted great interest as much as in industry as in research laboratories, due to they often show remarkable improvement in their mechanical and thermal properties when are compared with the virgin polymers. Among nanocomposites, nanoclay-reinforced polymers have been widely studied, specifically, those formed by a thermosetting polymer matrix, like unsaturated polyester crosslinked resin reinforced with layered silicates, like montmorillonite. In this work we have prepared nanocomposites formed by an isophtalic unsaturated polyester crosslinked resin (UP) reinforced with different contents (2-10 wt%) of organic modified montmorillonite (OMMT). The UP/OMMT nanocomposites have been prepared following different procedures and the structural characterization has been carried out by using X-ray diffraction (XRD). In all the cases an increase of the d-spacing between layers of the OMMT has been detected. The objective of this study is to analyze the thermal and mechanical behaviour of nanocomposites. For all of the reinforced systems, the glass transition temperatures values, Tg, obtained by differential scanning calorimetry (DSC) and dynamic-mechanical thermal analysis, (DMTA) are higher than the corresponding ones to neat UP. On the other hand, the OMMTP mechanical behaviour has been evaluated by DMTA and by tensile tests. Both techniques reveal an increase in Young modulus, however, a decrease of the tensile strength is observed in all the reinforced systems. PMID:20355515

Calvo, S; Prolongo, M G; Salom, C; Masegosa, R M

2010-04-01

207

Identification of sensitizing diethyleneglycol maleate in a two-component polyester cement.  

PubMed

Unsaturated polyester (UP) cement caused allergic contact dermatitis in car repair work. The resin was a condensate of polyols and maleic anhydride with reactive solvent, auxiliary substances, and inorganic reinforcement substances. To identify the causative chemicals, the cement was tested on a sensitized patient. For analysis, samples of the resin were eluted with acetone and eluted with hexane to precipitate inorganic material and large polyester molecules. The eluate was evaporated. The remainder, dissolved in acetone, was separated into fractions on silica plates by thin layer chromatography (TLC). On the developed (hexane/chloroform, 15/85) plates, 20 bands were obtained under UV-light at 254 nm. Samples of the bands were scraped and used for patch testing. The scraping at a retention factor (Rf) of 0.24 caused a skin reaction. The bands at this retention were removed from six plates, combined, eluted with acetone and purified again by TLC. The purified fraction mixed in petrolatum in the dilution series was used for conclusive patch testing on the patient. An allergic reaction was induced at down to 0.003% wt/wt. According to MS and IR analyses, the isolated compound was diethyleneglycol maleate (DEGM, MW204). In addition to the resin part, the sanding dust also contained this monomer. PMID:12000327

Pfäffli, Pirkko; Jolanki, Riitta; Estlander, Tuula; Tarvainen, Kyllikki; Kanerva, Lasse

2002-03-01

208

Hyperbranched polyester-based fluorescent probe for histone deacetylase via aggregation-induced emission.  

PubMed

Aberrant expression of histone deacetylases (HDACs) is related to various types of cancer and is associated with increased proliferation of tumor cells. Hence, the detection of HDAC activities is of great significance for medical sciences as well as biological diagnostics. Herein, we report a hyperbranched polyester-based one-step fluorescent assay for HDAC. This assay system consists of two water-soluble components: the hyperbranched polyester coupled with the acetylated lysine groups (H40-Lys(Ac)) and the negatively charged TPE derivative bearing two sulfonic acid groups (TPE-2SO3(-)). HDAC triggers the deacetylation of H40-Lys(Ac), thereby turning the electroneutral polymer into the positively charged one. Consequently, complexation occurs between the positively charged polymer and the negatively charged TPE-2SO3(-), thereby leading to the formation of nanoaggregates due to electrostatic interaction. Eventually, the fluorescence enhancement as a result of AIE effect is achieved. This assay system is operable in aqueous media with very low detection limit of 25 ng/mL. The system is capable of detecting HDAC in such biological fluid as serum, and this strategy may provide a new and effective approach for enzyme assay. PMID:24251690

Yu, Changmin; Wu, Yinglong; Zeng, Fang; Li, Xizhen; Shi, Jianbin; Wu, Shuizhu

2013-12-01

209

Engineered Corynebacterium glutamicum as an endotoxin-free platform strain for lactate-based polyester production.  

PubMed

The first biosynthetic system for lactate (LA)-based polyesters was previously created in recombinant Escherichia coli (Taguchi et al. 2008). Here, we have begun efforts to upgrade the prototype polymer production system to a practical stage by using metabolically engineered Gram-positive bacterium Corynebacterium glutamicum as an endotoxin-free platform. We designed metabolic pathways in C. glutamicum to generate monomer substrates, lactyl-CoA (LA-CoA), and 3-hydroxybutyryl-CoA (3HB-CoA), for the copolymerization catalyzed by the LA-polymerizing enzyme (LPE). LA-CoA was synthesized by D: -lactate dehydrogenase and propionyl-CoA transferase, while 3HB-CoA was supplied by ?-ketothiolase (PhaA) and NADPH-dependent acetoacetyl-CoA reductase (PhaB). The functional expression of these enzymes led to a production of P(LA-co-3HB) with high LA fractions (96.8 mol%). The omission of PhaA and PhaB from this pathway led to a further increase in LA fraction up to 99.3 mol%. The newly engineered C. glutamicum potentially serves as a food-grade and biomedically applicable platform for the production of poly(lactic acid)-like polyester. PMID:22127753

Song, Yuyang; Matsumoto, Ken'ichiro; Yamada, Miwa; Gohda, Aoi; Brigham, Christopher J; Sinskey, Anthony J; Taguchi, Seiichi

2012-03-01

210

Covering Walls With Fabrics.  

E-print Network

of cream. Lightweight fabrics, such as broadcloth and muslin, require glue the consistency of milk. Apply glue with a brush to one width of fabric at a time, going 1 inch past the measured width. Usually, glue applications are more successful if done... fabrics to walls: Permanent Methods ? Adhesive paste or glue Temporary Methods ? Shirring ? Double-stick tape ? Fabric closure tape ? Staple, tack or nail ? Starch Permanent Application Fabrics are permanently installed by gluing them...

Anonymous,

1979-01-01

211

The effect of woven and non-woven fiber structure on mechanical properties polyester composite reinforced kenaf  

NASA Astrophysics Data System (ADS)

The effects of woven and non-woven kenaf fiber on mechanical properties of polyester composites were studied at different types of perform structures. Composite polyester reinforced kenaf fiber has been prepared via hand lay-up process by varying fiber forms into plain weave, twill and mats structure. The reinforcing efficiency of different fiber structure was compared with control of unreinforced polyester sample. It was found that the strength and stiffness of the composites are largely affected by fiber structure. A maximum value for tensile strength of composite was obtained for twill weave pattern of fiber structure while no significant different for plain weave and mat structure. The elastic modulus of composite has shown some improvement on plain and twill weave pattern. Meanwhile, lower value of modulus elasticity achieved by mats structure composite as well as control sample. The modulus of rupture and impact resistance were also analyzed. The improvement of modulus of rupture value can be seen on plain and twill weave pattern. However impact resistance doesn't show significant improvement in all types of structure except for mat fiber. The mechanical properties of kenaf fiber reinforced polyester composite found to be increased with woven and non-woven fiber structures in composite.

Ratim, S.; Bonnia, N. N.; Surip, S. N.

2012-07-01

212

Dilatation of Stent-Grafts by Luminal Pressures: Experimental Evaluation of Polytetrafluoroethylene (PTFE) and Woven Polyester Grafts  

SciTech Connect

Purpose: To evaluate the effect on dilatation of three types of covering materials used for endovascular stent-grafts.Methods: Stent-grafts with three types of covering material [0.1-mm polytetrafluoroethylene (PTFE), 0.2-mm PTFE, and 0.15-mm woven polyester] were placed in a fluid circuit. For the pulsatile pressure test, the luminal pressure of 190/130 mmHg was loaded up to 300,000 pulses. For the static pressure test, the luminal pressure was increased from 50 to 300 mmHg at 50-mmHg increments. The percent of dilatation of each stent-graft was compared.Results: The 0.1-mm PTFE stent-graft was significantly more dilated than the 0.2-mm PTFE and the 0.15-mm woven polyester stent-graft (p < 0.005) in both examinations. There was no significant difference between the 0.2-mm PTFE and the 0.15-mm woven polyester stent-grafts. The dilatation of the 0.1-mm PTFE stent-graft was irreversible.Conclusion: The 0.15-mm woven polyester and the 0.2-mm PTFE stent-grafts may be preferable to the 0.1-mm PTFE stent-graft with regard to dilatation and deformity.

Suzuki, Kojiro; Ishiguchi, Tsuneo; Kawatsu, Shoji; Iwai, Hiroyoshi; Maruyama, Kunihiro; Ishigaki, Takeo [Department of Radiology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan)

2001-03-15

213

Cure characterization of an unsaturated polyester resin using near-infrared, fluorescence and UV/visible reflection spectroscopies  

NASA Astrophysics Data System (ADS)

This dissertation seeks to characterize the cure reaction of an unsaturated polyester resin using near-infrared, fluorescence and UV/Visible reflection spectroscopies. The results will provide a foundation for developing fiber-optic in-situ cure monitoring techniques based on near-infrared, fluorescence, and UV/Visible reflection spectroscopies for an unsaturated polyester resin system. Near-infrared spectra of the unsaturated polyester resin during cure showed a decrease in absorption at 1629, 2087, 2117, and 2227 nm. Model compounds representing the reactants and products of the cure reaction were characterized, and assignment of peaks in the NIR were made. Conversion of styrene and vinylene, determined from NIR measurements, were compared with values obtained using conventional FTIR measurements. Discrepancies between conversion values determined from NIR and FTIR measurements were attributed to a difference in sample sizes used for measurement. Using a microgel based reaction mechanism, the effects of temperature on the conversion of styrene and vinylene was discussed. A strong fluorescence emission was found during cure of the unsaturated polyester resin. As the reaction proceeded, the emission intensity at 306 nm increased. Model compound studies confirmed that the unsaturated polyester vinylene component exhibits negligible fluorescence when excited at 250 nm. The fluorescence emission at 306 nm was attributed to a reduced self-quenching effect of styrene monomer. In-situ fluorescence characterization of the cure reaction was also attempted. Fiber-optic fluorescence measurements taken in-situ at 75°C were found to be higher than those taken by fiber-optics at room temperature, indicating a temperature effect on the fluorescence emission. These results may be a consequence of the static quenching behavior of styrene monomer. UV/Visible reflection spectra of styrene showed a decrease in the % Reflectance at 255 nm with reaction time. This decrease was attributed to an overall reduction in the absorption index as styrene reacts to form polystyrene. Conversion of styrene calculated from UV/Visible reflection and FTIR measurements were in close agreement. A preliminary investigation into the use of UV/Visible reflection spectroscopy to cure monitor a styrene containing unsaturated polyester resin was also performed. A similar decrease in the % Reflectance at 255 nm with cure time was reported for the unsaturated polyester resin.

Grunden, Bradley Lyn

214

The effects of a moisture-wicking fabric shirt on the physiological and perceptual responses during acute exercise in the heat.  

PubMed

This study investigated the effects that a form fitted, moisture-wicking fabric shirt, promoted to have improved evaporative and ventilation properties, has on the physiological and perceptual responses during exercise in the heat. Ten healthy male participants completed two heat stress tests consisting of 45 min of exercise (50% VO2peak) in a hot environment (33 °C, 60% RH). One heat stress test was conducted with the participant wearing a 100% cotton short sleeved t-shirt and the other heat stress test was conducted with the participant wearing a short sleeved synthetic shirt (81% polyester and 19% elastane). Rectal temperature was significantly lower (P < 0.05) in the synthetic condition during the last 15 min of exercise. Furthermore, the synthetic polyester shirt retained less sweat (P < 0.05). As exercise duration increases, the ventilation and evaporation properties of the synthetic garment may prove beneficial in the preservation of body temperature during exercise in the heat. PMID:24768089

De Sousa, Justin; Cheatham, Christopher; Wittbrodt, Matthew

2014-11-01

215

DESIGN [fabrication] BUILD  

E-print Network

DESIGN [fabrication] BUILD proposes a new relationship among the architect, homeowner, and fabricator/assembler through the use of parametric software in order to create a truly customizable prefabricated home. This ...

Rader, Nicolas Glen

2006-01-01

216

Contextualizing urban mobile fabrics  

E-print Network

This thesis is focus on the urban fabric issues. To be more specific, I will focus on the "Mobile Fabrics" within the larger Asian urban context. Instead of working with a specific geographical site; I will focus on the ...

Lin, Michael Chia-Liang

2007-01-01

217

N-Alkylated dinitrones from isosorbide as cross-linkers for unsaturated bio-based polyesters  

PubMed Central

Summary Isosorbide was esterified with acryloyl chloride and crotonic acid yielding isosorbide diacrylate (9a) and isosorbide dicrotonate (9b), which were reacted with benzaldehyde oxime in the presence of zinc(II) iodide and boron triflouride etherate as catalysts to obtain N-alkylated dinitrones 10a/b. Poly(isosorbide itaconite -co- succinate) 13 as a bio-based unsaturated polyester was cross-linked by a 1,3-dipolar cycloaddition with the received dinitrones 10a/b. The 1,3-dipolar cycloaddition led to a strong change of the mechanical properties which were investigated by rheological measurements. Nitrones derived from methyl acrylate (3a) and methyl crotonate (3b) were used as model systems and reacted with dimethyl itaconate to further characterize the 1,3-dipolaric cycloaddition. PMID:24991239

Goerz, Oliver

2014-01-01

218

Isosorbide as the structural component of bio-based unsaturated polyesters for use as thermosetting resins.  

PubMed

In recent years, the development of renewable bio-based resins has gained interest as potential replacements for petroleum based resins. Modified carbohydrate-based derivatives have favorable structural features such as fused bicyclic rings that offer promising candidates for the development of novel renewable polymers with improved thermomechanical properties when compared to early bio-based resins. Isosorbide is one such compound and has been utilized as the stiffness component for the synthesis of novel unsaturated polyesters (UPE) resins. Resin blends of BioUPE systems with styrene were shown to possess viscosities (120-2200 cP) amenable to a variety of liquid molding techniques, and after cure had Tgs (53-107 °C) and storage moduli (430-1650 MPa) that are in the desired range for composite materials. These investigations show that BioUPEs containing isosorbide can be tailored during synthesis of the prepolymer to meet the needs of different property profiles. PMID:24188843

Sadler, Joshua M; Toulan, Faye R; Nguyen, Anh-Phuong T; Kayea, Ronald V; Ziaee, Saeed; Palmese, Giuseppe R; La Scala, John J

2014-01-16

219

Radiation curing of polyester resin modified with acrylic acid and its salts  

NASA Astrophysics Data System (ADS)

Polyester resin containing acrylic acid or its salts was cured with ? 60Co radiation. The course of curing was examined, the gel content and polymerization shrinkage were measured and also thermographic and IR absorption analyses were carried out. It was found that manganese, iron and copper acrylates inhibited the curing of resin while the remaining additives showed a slightly stimulating action. All the additives decreased the polymerization shrinkage by a factor of 2-3 and iron acrylate by as much as 8 times (up to 1%). They also increased the activation energy of the thermal decomposition of resin, and calcium, barium and copper acrylates increased the thermal stability of resin by 20 K. IR absorption spectra showed that acrylic acid and its salts reacted mainly with the monomeric component of the resin (styrene) whereas iron and copper acrylates first attacked the unsaturated bonds of the oligoester.

Szali?ska, H.; Pietrzak, M.; Janowska, G.

220

Dielectric and thermal analysis of radiation curing of insaturated polyester resins  

NASA Astrophysics Data System (ADS)

Radiation curing of unsaturated polyester resins were studied by combining dielectric and thermal analysis. Dielectric permitivities were measured by stepwise changing of frequency during the course of 60Co y-irradiation at constant temperature or by simultaneous change of frequency and temperature after irradiation. A continuous shift of the glass-transition of the resin and a change of the dielectric relaxation time distribution was observed as radiation crosslinking reaction proceeded. The shape of the dielectric spectrum bands indicated a heterogeneous nature of the transition which increased with increasing degree of curing. The long reaction time limiting values of the permittivity were found to be considerably higher than the unrelaxed limit showing the existence of a limiting conversion effect.

Jel?i?, Z.; Hedvig, P.; Ranogajec, F.; Dvornik, I.

221

On the suitability of fiberglass reinforced polyester as building material for mesocosms.  

PubMed

Gel- and topcoat surface layers on fiberglass [glass-reinforced plastic (GRP)] made of unsaturated resin based on isophthalic acid polyester and neopentyl glycol (ISO-NPG) were tested for leaching, ecotoxicity of water eluates, and abrasion by river sediments at a current speed of 0.5 m * s-1. Leaching from topcoat tempered at low temperature was significant, whereas it was negligible from highly tempered gelcoat. Water eluates from both gel-and topcoat were nontoxic in routinely employed biotests (bacteria, algae, daphnids). No abrasion by river sediments was detectable. Based on these results, GRP with gelcoat made of ISO-NPG is considered a suitable building material for mesocosms. PMID:10381304

Berghahn, R; Brandsch, J; Piringer, O; Pluta, H J; Winkler, T

1999-07-01

222

Chemical and Physical Changes in a Hydrolyzed Poly(ester urethane)  

SciTech Connect

Hydrolytic degradation has been shown to be a significant problem for poly(ester urethane) elastomers exposed to high humidity environments. The ester group in the soft segment is particularly susceptible to hydrolysis. One of the products of this reaction is a carboxylic acid group that catalyses further hydrolysis. The resulting reduction in molecular weight leads to deterioration of the elastomer's mechanical properties. In this paper we have measured the extent of the hydrolysis reaction by {sup 13}C NMR spectroscopy. In addition we have measured the spin-spin relaxation time of the soft phase and followed the increase in mobility of these segments. Both measurements were performed on the solid polymer. These measurements provide an excellent monitoring tool of the chemical and physical state of polymer during the aging process.

ASSINK,ROGER A.; CELINA,MATHIAS C.; LANG,DAVID P.

1999-11-03

223

Identification of Heredity Kernels and Their Influence on the Life Time of Glass/Polyester Composites  

NASA Astrophysics Data System (ADS)

One of the major problems encountered in prediction of hereditary viscoelastic behavior of polymeric composites is the determination of heredity kernels. This issue comes down to identification of the model characterizing the viscoelastic properties of these materials. The purpose of this work is to propose a model for prediction of viscoelastic nonlinear behavior of laminate composite with polyester matrix, through the study and analysis of heredity kernels and their influence on the life time of this material. Identification of this model required experimental determination at room temperature, of viscoelastic parameters of heredity kernels by macroscopic approach. These data provide predictive tools for establishment of the life time and long term stress limit under static complex loading for this type of material.

Olodo, E. T.; Adjovi, E. C.; Adanhounme, V.

2014-11-01

224

At-line process monitoring of polyester production by mid-IR spectroscopy  

NASA Astrophysics Data System (ADS)

At-line monitoring techniques can be used to gain better control of manufacturing processes. The result of better control is a more efficient process; one where product quality is improved and operating costs are reduced. The current study examines the reaction of phthalic anhydride, maleic anhydride, propylene glycol and diethylene glycol to produce polyester resins. The performance of the resin is high dependent on the composition. Because it is not a simple matter to charge the batch reactor with the necessary proportion of reactants, adjustments are often necessary. To reduce or eliminate the number of off-grade batches a rapid at-line mid-infrared method has been developed. The measurement can be completed in a matter of minutes and requires no sample preparation. Initial reactant charges can be determined despite the fact that the reaction has begun by the time the batch is homogeneous and can be sampled.

Donahue, Steven M.; Van Order, Norman E., Jr.; Forster, Wolfgang

1993-12-01

225

Exploring Products: Nano Fabrics  

NSDL National Science Digital Library

In this activity, learners explore how the application of nano-sized "whiskers" can protect clothing from stains. Learners investigate the hydrophobic properties of pants made from nano fabric and ordinary fabric. Use this activity to talk about products that we can already buy that use nanotechnology, like treated fabrics, water filters, sunscreen and stuffed animals that have silver nanoparticles.

Nanoscale Informal Science Education Network

2010-01-01

226

Space reactor shielding fabrication  

NASA Technical Reports Server (NTRS)

The fabrication of space reactor neutron shielding by a melting and casting process utilizing lithium hydride is described. The first neutron shield fabricated is a large pancake shape 86 inches in diameter, containing about 1700 pounds of lithium hydride. This shield, fabricated by the unique melting and casting process, is the largest lithium hydride shield ever built.

Welch, F. H.

1972-01-01

227

Fungal Communities Associated with the Biodegradation of Polyester Polyurethane Buried under Compost at Different Temperatures  

PubMed Central

Plastics play an essential role in the modern world due to their low cost and durability. However, accumulation of plastic waste in the environment causes wide-scale pollution with long-lasting effects, making plastic waste management expensive and problematic. Polyurethanes (PUs) are heteropolymers that made up ca. 7% of the total plastic production in Europe in 2011. Polyester PUs in particular have been extensively reported as susceptible to microbial biodegradation in the environment, particularly by fungi. In this study, we investigated the impact of composting on PUs, as composting is a microbially rich process that is increasingly being used for the processing of green waste and food waste as an economically viable alternative to landfill disposal. PU coupons were incubated for 12 weeks in fresh compost at 25°C, 45°C, and 50°C to emulate the thermophilic and maturation stages of the composting process. Incubation at all temperatures caused significant physical deterioration of the polyester PU coupons and was associated with extensive fungal colonization. Terminal restriction fragment length polymorphism (TRFLP) analysis and pyrosequencing of the fungal communities on the PU surface and in the surrounding compost revealed that the population on the surface of PU was different from the surrounding compost community, suggesting enrichment and selection. The most dominant fungi identified from the surfaces of PU coupons by pyrosequencing was Fusarium solani at 25°C, while at both 45°C and 50°C, Candida ethanolica was the dominant species. The results of this preliminary study suggest that the composting process has the potential to biodegrade PU waste if optimized further in the future. PMID:24056469

Zafar, Urooj; Houlden, Ashley

2013-01-01

228

Usefulness of an aluminized polyester film for reducing heat in polyethylene calf hutches.  

PubMed

This study determined the efficacy of a radiant barrier material used in the construction industry to moderate summer temperatures in polyethylene calf hutches. The cover consisted of a single layer of two-sided reflective aluminized polyester film with a center polyester scrim reinforcement (reflectivity?=?95%). At each of two dairies, six hutches containing a young calf were either uncovered (control) or had reflective covers across the top and sides of the hutch, leaving the front, back, and 1.2?×?1.8-m attached outdoor wire pen exposed. Duplicate loggers mounted 20 cm above the flooring in the center of each hutch recorded interior temperature at 30-min intervals over 22 days during late August to early September. The mean daily interior peak temperatures in each of the hutches over 21 days of observation were significantly less (P?

Binion, W R; Friend, T H; Holub, G A

2014-11-01

229

Enzymatic degradation of polyester films by a cutinase-like enzyme from Pseudozyma antarctica: surface plasmon resonance and atomic force microscopy study.  

PubMed

Enzymatic degradation of polyester films by a cutinase-like enzyme from Pseudozyma antarctica JCM10317 (PaE) was analyzed by surface plasmon resonance (SPR). The adsorption of PaE and the degradation rate for polyester films were quantitatively monitored by a positive and negative SPR signal shifts, respectively. The decrease in SPR signal and the erosion depth of amorphous poly(L-lactide) (a-PLLA) film measured by atomic force microscopy (AFM) had a linear relationship, and the weight loss was estimated from the AFM data combined with a density of a-PLLA film. Furthermore, SPR sensorgrams for various polyester films showed that degradation rate of poly(?-caprolactone) and poly(butylene succinate-co-adipate) which contain C6 units was higher than that of other polyesters such as poly(butylene succinate) and a-PLLA. These results suggest that C6 is the preferred chain length as substrates for PaE. PMID:23339012

Shinozaki, Yukiko; Kikkawa, Yoshihiro; Sato, Shun; Fukuoka, Tokuma; Watanabe, Takashi; Yoshida, Shigenobu; Nakajima-Kambe, Toshiaki; Kitamoto, Hiroko K

2013-10-01

230

Reduction of polyester resin shrinkage by means of epoxy resin—II. Epoxy resin modified with acrylamide and N-hydroxymethyloloacrylamide  

NASA Astrophysics Data System (ADS)

The possibility was investigated of reducing the shrinkage of unsaturated polyester resin taking place in radiation-induced curing, by the addition of epoxy resin. In order to combine chemically both resins, the epoxy component was modified by introducing unsaturated bonds via acrylamide and N-hydroxymethyloloacrylamide. A composition of 90% unsaturated polyester resin and 10% acrylamide-modified epoxy resin, filled with silica (1:1.5), showed a volume shrinkage below 2%.

Pietrzak, M.; Brzostowski, A.

231

Kenaf/recycled Jute Natural Fibers Unsaturated Polyester Composites: Water Absorption/dimensional Stability and Mechanical Properties  

NASA Astrophysics Data System (ADS)

Effects of water absorption on the flexural properties of kenaf-unsaturated polyester composites and kenaf/recycled jute-unsaturated polyester composites were investigated. In the hybrid composites, the total fiber content was fixed to 20 wt%. In this 20 wt%, the addition of jute fiber varied from 0 to 75%, with increment of 25%. The result demonstrates the water absorption and the thickness swelling increased with increase in immersion time. Effects of water absorption on flexural properties of kenaf fiber composites can be reduced significantly with incorporation of recycled jute in composites formulation. The process of absorption of water was found to approach Fickian diffusion behavior for both kenaf composites and hybrid composites.

Osman, Ekhlas A.; Vakhguelt, Anatoli; Sbarski, Igor; Mutasher, Saad A.

2012-03-01

232

Surface Assisted Laser Desorption Ionization-Mass Spectrometry (SALDI-MS) for Analysis of Polyester Degradation Products  

NASA Astrophysics Data System (ADS)

Novel surface assisted laser desorption ionization-mass spectrometry (SALDI-MS) method was developed for rapid analysis of low molecular mass polyesters and their degradation products by laser desorption ionization-mass spectrometry. Three polycaprolactone materials were analyzed by the developed method before and after hydrolytic degradation. The signal-to-noise values obtained by SALDI-MS were 20-100 times higher compared with the ones obtained by using traditional MALDI-MS matrices. A clean background at low mass range and higher resolution was obtained by SALDI-MS. Different nanoparticle, cationizing agent, and solvent combinations were evaluated. Halloysite nanoclay and magnesium hydroxide showed the best potential as SALDI surfaces. The SALDI-MS spectrum of the polyester hydrolysis products was verified by ESI-MS. The developed SALDI-MS method possesses several advantages over existing methods for similar analyses.

Aminlashgari, Nina; Hakkarainen, Minna

2012-06-01

233

Fabrication of cell microintegrated blood vessel constructs through electrohydrodynamic atomization  

PubMed Central

Biodegradable synthetic matrices that resemble the size scale, architecture and mechanical properties of the native extracellular matrix can be fabricated through electrospinning. Tubular conduits may also be fabricated with properties appropriate for vascular tissue engineering. Achieving large cell infiltrate within the electrospun matrix in vitro remains time consuming and challenging. This difficulty was overcome by electrospraying smooth muscle cells concurrently with electrospinning of a biodegradable, elastomeric poly(ester urethane)urea (PEUU) small diameter conduit. Constructs were cultured statically or in spinner flasks. Hematoxylin and eosin (H&E) staining demonstrated qualitatively uniform SMC integration radially and circumferentially within the conduit after initial static culture. In comparison with static culture, samples cultured in spinner flasks indicated 2.4 times more viable cells present from MTT and significantly larger numbers of SMCs spread within the electrospun fiber networks by H&E image analysis. Conduits were strong and flexible with mechanical behaviors that mimicked those of native arteries, including static compliance of 1.6 ± 0.5 × 10?3 mmHg?1, dynamic compliance of 8.7 ± 1.8 × 10?4 mmHg?1, burst strengths of 1750 ± 220 mmHg, and suture retention. This method to rapidly and efficiently integrate cells into a strong, compliant biodegradable tubular matrix represents a significant achievement as a tissue engineering approach for blood vessel replacement. PMID:17337048

Stankus, John J.; Soletti, Lorenzo; Fujimoto, Kazuro; Hong, Yi; Vorp, David A.; Wagner, William R.

2007-01-01

234

Studies of the aging effect on the level of isocyanate residues in polyester-based can coating systems  

Microsoft Academic Search

A methyl ethyl ketone oxime-blocked isocyanate was used as a crosslinking agent in the curing of polyester–polyurethane (PEPU)\\u000a can coatings. The completeness of cure was assessed from the amount of residual (un-reacted) isophorone diisocyanate (IPDI)\\u000a trimer that was presented in the coating after curing. This amount of residual trimer depended strongly on the temperature\\u000a at which the curing was undertaken

C. Jiang; M. Driffield; E. L. Bradley; P. K. T. Oldring; P. Cooke; L. Castle; J. T. Guthrie

2009-01-01

235

Mechanical and thermal studies of intercross-linked networks based on siliconized polyurethane-epoxy\\/unsaturated polyester coatings  

Microsoft Academic Search

Two different intercross-linked networks (ICN) of siliconized polyurethane-epoxy\\/unsaturated polyester (UP) coatings were developed. Epoxy and UP resins were modified with polyurethane (PU) prepolymer and hydroxyl terminated polydimethylsiloxane (HTPDMS) using ?-aminopropyl triethoxysilane (?-APS) and vinyltriethoxysilane (VTES) as silane cross-linkers and dibutyltindilaurate (DBTL) as catalyst. Aromatic polyamine adduct (A) and aliphatic amine (B) were used as curatives for epoxy and methyl isobutyl

A Anand Prabu; M Alagar

2004-01-01

236

Enzymatic and whole-cell synthesis of lactate-containing polyesters: toward the complete biological production of polylactate  

Microsoft Academic Search

The importance of polylactic acid, a representative bio-based polyester, has been established on a worldwide scale in response\\u000a to emerging global environmental problems such as green house gas emission and limited petroleum consumption. The current\\u000a methods for generating this bio-based polymer involve biological synthesis and lactic acid (LA) fermentation, followed by\\u000a chemical ring-opening polymerization. Among the research community working on

Ken’ichiro Matsumoto; Seiichi Taguchi

2010-01-01

237

Effects of Moisture Absorption and Test Method on the Properties of E-glass\\/Polyester Hull Laminates  

Microsoft Academic Search

Effects of moisture absorption on the tensile, compressive, shear, bending and bending fatigue properties of an iso-polyester\\/E-glass hull laminate were studied. Fickian diffusion constants were found that closely modeled moisture absorption. Comparisons were made of standard moisture experiments using boiling water versus long-term exposure. Results indicated that the boiling water test yielded significantly conservative values. Fatigue endurance limits were found

Paul H. Miller

2002-01-01

238

Finite element modeling and experimental study on bending and vibration of laminated stiffened glass fiber\\/polyester composite plates  

Microsoft Academic Search

In this paper, free vibration and bending failure of laminated stiffened glass fiber\\/polyester composite plates with laminated open section (rectangular or T-shaped) and closed section (hat shaped) of stiffeners have been studied by finite element method and experiment. A 9-noded isoparametric element with 9 degrees of freedom per node is developed for the plates. The stiffener element is a 3-noded

Tran Ich Thinh; Tran Huu Quoc

2010-01-01

239

Mechanical and Abrasive Wear Behavior of Coleus Spent Filled Unsaturated Polyester\\/Polymethyl Methacrylate Semi Interpenetrating Polymer Network Composites  

Microsoft Academic Search

Mechanical properties and three-body abrasive wear behavior of 5 and 10% w\\/w bio-based coleus spent (CS) filled and unfilled semi interpenetrating polymer network composites of unsaturated polyester\\/polymethyl methacrylate (80\\/20) have been studied. The tensile strength and elongation at break has been evaluated using 4302 Hounsfield Universal testing machine. The effect of abrading distances viz., 150, 300, 450, and 600 m

Murtuza Ali Syed; Siddaramaiah; B. Suresha; Akheel Ahmed Syed

2009-01-01

240

Reduction of polyester resin shrinkage by means of epoxy resin—I. Epoxy resin modified with acids  

NASA Astrophysics Data System (ADS)

An attempt was made to decrease the shrinkage of unsaturated polyester resin, taking place during radiation-induced curing, by the addition of epoxy resin. In order to combine chemically both resins, the epoxy component was modified with cinnamic and acrylic acids. A composition of 90 parts of polyesster resin, 10 parts of epoxy resin modified with cinnamic acid, and 150 parts of a silica filler showed a volume shrinkage of 1.2%.

Pietrzak, M.; Brzostowski, A.

241

New poly(ester urea) derived from l-leucine: Electrospun scaffolds loaded with antibacterial drugs and enzymes.  

PubMed

Electrospun scaffolds from an amino acid containing poly(ester urea) (PEU) were developed as promising materials in the biomedical field and specifically in tissue engineering applications. The selected poly(ester urea) was obtained with a high yield and molecular weight by reaction of phosgene with a bis(?-aminoacyl)-?,?-diol-diester monomer. The polymer having l-leucine, 1,6-hexanediol and carbonic acid units had a semicrystalline character and relatively high glass transition and melting temperatures. Furthermore it was highly soluble in most organic solvents, an interesting feature that facilitated the electrospinning process and the effective incorporation of drugs with bactericidal activity (e.g. biguanide derivatives such as clorhexidine and polyhexamethylenebiguanide) and enzymes (e.g. ?-chymotrypsin) that accelerated the degradation process. Continuous micro/nanofibers were obtained under a wide range of processing conditions, being diameters of electrospun fibers dependent on the drug and solvent used. Poly(ester urea) samples were degradable in media containing lipases and proteinases but the degradation rate was highly dependent on the surface area, being specifically greater for scaffolds with respect to films. The high hydrophobicity of new scaffolds had repercussions on enzymatic degradability since different weight loss rates were found depending on how samples were exposed to the medium (e.g. forced or non-forced immersion). New scaffolds were biocompatible, as demonstrated by adhesion and proliferation assays performed with fibroblast and epithelial cells. PMID:25492010

Díaz, Angélica; Del Valle, Luis J; Tugushi, David; Katsarava, Ramaz; Puiggalí, Jordi

2015-01-01

242

In vitro characterization of polyesters of aconitic acid, glycerol, and cinnamic acid for bone tissue engineering.  

PubMed

In this study, a novel class of polyesters of glycerol, aconitic acid, and cinnamic acid were synthesized along with their hydroxyapatite (HA) composites, and studied for their potential application in bone defect repair. An osteogenic study was conducted with human adipose derived mesenchymal stem cells (hASCs) to determine the osteoinductive ability of aconitic acid-glycerol (AG) polyesters, AG:HA (80:20), aconitic acid-glycerol-cinnamic acid (AGC) polyesters, and AGC:HA (80:20) to serve as bone scaffolds. The results indicate that AGC scaffolds have the highest mechanical strength in comparison to AG, AG:HA (80:20), and AGC:HA (80:20) scaffolds due to its low porosity. It was determined by cytotoxicity and osteogenesis experiments that hASCs cultured for 21 days on AG:HA (80:20) scaffolds in stromal medium exhibited a greater number of live cells than control PCL:HA composites. Moreover, hASCs cultured on foamed AG:HA (80:20) scaffolds resulted in the highest levels of mineralization, increased alkaline phosphatase (ALP) expression, and the greatest osteocalcin (OCN) expression after 21 days. Overall, AG:HA (100:0 and 80:20) scaffolds had higher mechanical strength and cytocompatibility than the PCL:HA control. In vitro osteogenic study demonstrated that AG:HA (100:0 and 80:20) synthesized using sugarcane industry by-products hold potential as scaffolds for bone tissue engineering applications. PMID:25281649

Kanitkar, Akanksha; Chen, Cong; Smoak, Mollie; Hogan, Katie; Scherr, Thomas; Aita, Giovanna; Hayes, Daniel

2015-03-01

243

Damage of polyesters by the atmospheric free radical oxidant NO3 •: a product study involving model systems  

PubMed Central

Summary Manufactured polymer materials are used in increasingly demanding applications, but their lifetime is strongly influenced by environmental conditions. In particular, weathering and ageing leads to dramatic changes in the properties of the polymers, which results in decreased service life and limited usage. Despite the heavy reliance of our society on polymers, the mechanism of their degradation upon exposure to environmental oxidants is barely understood. In this work, model systems of important structural motifs in commercial high-performing polyesters were used to study the reaction with the night-time free radical oxidant NO3 • in the absence and presence of other radical and non-radical oxidants. Identification of the products revealed ‘hot spots’ in polyesters that are particularly vulnerable to attack by NO3 • and insight into the mechanism of oxidative damage by this environmentally important radical. It is suggested that both intermediates as well as products of these reactions are potentially capable of promoting further degradation processes in polyesters under environmental conditions. PMID:24204400

Goeschen, Catrin

2013-01-01

244

Fabrics for aeronautic construction  

NASA Technical Reports Server (NTRS)

The Bureau of Standards undertook the investigation of airplane fabrics with the view of finding suitable substitutes for the linen fabrics, and it was decided that the fibers to be considered were cotton, ramie, silk, and hemp. Of these, the cotton fiber was the logical one to be given primary consideration. Report presents the suitability, tensibility and stretching properties of cotton fabric obtained by laboratory tests.

Walen, E D

1918-01-01

245

Lobesia botrana IPM: electrospun polyester microfibers serve as biodegradable sex pheromone dispensers.  

PubMed

Modern insect pest management is faced with an increasingly sophisticated set of requirements. Control agent/dispenser combinations must be at the same time safe, nontoxic, inexpensive, reproducibly efficacious, environmentally compatible, biodegradable, and sustainable, and should be based on renewable resources. The methods employed preferably should be suitable for the growing and tightly controlled organic growing sector as well. All this calls for a level of sophistication and reproducibility previously unknown. Only very few systems can offer this kind of performance, but fortunately can be found in the area of suitable pheromone/dispenser combinations. This report is an attempt to adapt electrospun Ecoflex polyester micro fibers of the Greiner-Wendorff type to the very specific needs of the grape growing industry. Specifically required are "semi-intelligent" dispenser materials. On a weight basis, the electrospun product should achieve as high a proportion as possible of "retainable" sex pheromone (E,Z)-7,9-dodecadienyl acetate of Lobesia botrana (Lep.: Tortricidae) and should release it as uniformly as possible into the surrounding airspace. Using the Doye bioassay, some progress indeed has recently been achieved with electrospun Ecoflex microfibers of 0.5-3.5 microm diameter. They were employed as dispensers for programmed sex pheromone release with an effective mating disruption duration of up to seven weeks. With one microfiber/pheromone treatment, this covers one entire flight period of the trivoltine L. botrana. Mechanical application of this microfiber/pheromone preparation (with the option of automation) is possible. Disruption effects are comparable with those of commercially available dispensers of the Isonet type. Exposed under vineyard conditions, Ecoflex polyester fibers are a spider silk like material which is biodegradable within half a year. Thus, after releasing its pheromone load, it does not need removal, which saves one cultivation step. The fibers are under rigorous quantitative pretesting by analytical lab methods such as scanning EM, CLSA, timed weight loss curves in isothermal wind tunnels, and by thermogravimetry. Grapes produced under protection with these pheromone-charged biodegradable and mechanically deployable Ecoflex microfibers are completely free of pesticide residues. PMID:25145245

Hummel, Hans E; Langner, S S

2013-01-01

246

Evaluation of genotoxic potential of styrene in furniture workers using unsaturated polyester resins.  

PubMed

Styrene is a widely used chemical, mostly in making synthetic rubber, resins, polyesters, plastics and insulators. Increasing attention has been focused on this compound since experiments using cytogenetic end-points have implicated styrene as a potential carcinogen and mutagen. In order to perform biological monitoring of genotoxic exposure to styrene monomer, we evaluated the urinary thioether (UT) excretion, and sister chromatid exchanges (SCEs) and micronuclei (MN) in peripheral lymphocytes from 53 furniture workers employed in small workplaces where polyester resin lamination processings were done and from 41 matched control subjects. The mean air concentration of styrene in the breathing zone of workers was 30.3 ppm. As a metabolic marker for styrene exposure, mandelic acid + phenylglyoxylic acid was measured in the urine and the mean value was 207 mg/g creatinine. The mean +/- SD value of UT excretions of workers was 4.43 +/- 3.42 mmol SH-/mol creatinine and also mean UT for controls was found to be a 2.75 +/- 1.78 mmol SH-/mol creatinine. The mean +/- SD/cell values of SCE frequency in peripheral lymphocytes from the workers and controls were 6.20 +/- 1.56 and 5.23 +/- 1.23, respectively. The mean +/- SD frequencies (%o) of MN in the exposed and control groups were 1.98 +/- 0.50 and 2.09 +/- 0.35, respectively. Significant effects of work-related exposure were detected in the UT excretion and SCEs analyzed in peripheral blood lymphocytes (p < 0.05 and p < 0.01, respectively). The MN frequency in lymphocytes from the styrene-exposed group did not differ from that in the controls (p > 0.05). Effect of smoking, age and duration of exposure on the genotoxicity parameters analyzed were also evaluated. In conclusion, although our data do not demonstrate a dose-response relationship, they do suggest that styrene exposure was evident and that this styrene exposure may contribute to the observed genotoxic damage in furniture workers. PMID:9294026

Karakaya, A E; Karahalil, B; Yilmazer, M; Aygün, N; Sarda?, S; Burgaz, S

1997-08-14

247

An Investigation of Thermal Characteristic of Mechanical Crimp Textured Polyester Yarn by Differential Scanning Calorimeter (DSC)  

NASA Astrophysics Data System (ADS)

Deficiencies related to the lack of bulk in flat continuous filament yarns make them unsuitable for apparel, home textiles as well as other applications such as car seat covering. Hence, texturising is employed to impart lofty and bulky characteristics to them. The two major texturising techniques employed for polyester yarn are false-twist and air-jet texturising. Out of these earlier technique depends on the thermoplasticity of the yarn being textured whereas the later one demands subsequent amount of compressed air to carry out cold fluid texturising. A new concept of mechanical crimp texturising has been designed to overcome these limitations of commercially successful techniques. In this new technique, pre-twisted FDY (Fully Drawn Yarn) flat multifilament yarn has been subjected to the higher false-twisting (depending on yarn fineness) action under the condition of underfeed (depending on ductility of parent yarn). The torque caused due to high level of false-twisting, forces the filaments to follow helical path at a certain angle (depends on magnitude of twist and denier per filament) to the filament yarn longitudinal axis. Internal stresses arising in single filaments tend to bend the filament and take the shape of spatial helical spring. After the yarn has passed through the false twisting unit, the initial twist would reassert itself and lock the already formed crimpy convolutions in position. Mechanical crimp textured polyester yarns with different pre-twist and false-twist levels have been subjected to thermal stress analysis using differential Scanning Calorimeter (DSC) in heat-cool-heat mode. The samples were heated at a rate of 10°C/minute. Almost all samples appear to be crystalline in nature. However, the melting endotherm does not show sharp peak. Instead, the diffuse nature of the peak is a signature of a partial crystalline nature (48%) of the samples. After melting the specimens, cooling of the same leads to crystallization of the material. This is exhibited by the exotherm. Heating the so-cooled samples, in general, increases their melting point in almost all samples. Thus melting event is shifted towards higher temperature, except for one sample in which pre-twist level is appreciably high. Thus, DSC is a very useful technique to select and optimize the pre-twist level and may provide quite a significant insight into the thermal stability of the mechanical crimp textured yarn.

Bhattacharya, Someshwar S.; Shaikh, Tasnim N.; Pratap, Arun

2010-06-01

248

Smart Fabrics Technology Development  

NASA Technical Reports Server (NTRS)

Advances in Smart Fabrics technology are enabling an exciting array of new applications for NASA exploration missions, the biomedical community, and consumer electronics. This report summarizes the findings of a brief investigation into the state of the art and potential applications of smart fabrics to address challenges in human spaceflight.

Simon, Cory; Potter, Elliott; Potter, Elliott; McCabe, Mary; Baggerman, Clint

2010-01-01

249

Structural Fabrication II Syllabus  

NSDL National Science Digital Library

This pdf contains a syllabus for a second course on structural fabrication as part of the Aerospace Technology Program. Topics include introduction to composites, structural fibers and matrices, core materials, basic moldless tools and techniques, and advanced composite fabrication and structural repair.

2011-08-03

250

Multifunctional cotton fabrics  

Microsoft Academic Search

Electrically conductive fabrics were produced by deposition of a thin film of doped polypyrrole on the surface of cotton fibres. In situ oxidative chemical polymerisation were carried out in aqueous solutions of pyrrole, oxidant and doping agents, at room temperature. Polypyrrole-coated fibres were characterized by Light Microscopy, SEM, EDX, FTIR and TGA. Moreover, fabric samples were also evaluated for moisture

Alessio Varesano; Annalisa Aluigi; Luca Florio; Riccardo Fabris

2009-01-01

251

Counterion Dynamics in Polyester-Sulfonate Ionomers with Ionic Liquid Counterions  

SciTech Connect

Conventional sodium cations (Na{sup +}) in sulfonated polyester ionomers were replaced with ammonium-based ionic liquid counterions. Counterion dynamics were measured by dielectric spectroscopy and linear viscoelastic response via oscillatory shear. Ion exchange from sodium counterions to ionic liquid counterions such as tetramethylammonium and tetrabutylammonium showed an order of 10{sup 4} increase in conductivity compared with sodium counterions, primarily attributed to weaker ionic interactions that lower the glass transition temperature. Electrode polarization was used in conjunction with the 1953 Macdonald model to determine the number density of conducting counterions and their mobility. Conductivity and mobility exhibit Vogel-Fulcher-Tammann (VFT) temperature dependences and both increased with counterion size. Conducting counterion concentrations showed Arrhenius temperature dependences, with activation energy reduced as counterion size increased. When ether-oxygen was incorporated into the mobile cation structure, self-solvating ability notably increased the conducting ion concentration. Weakened ion pairing interactions prove favorable for fundamental design of single-ion conductors for actuators, as ionic liquid counterions can provide both larger and faster strains, required by such electro-active devices.

Tudryn, Gregory J.; Liu, Wenjuan; Wang, Shih-Wa; Colby, Ralph H. (Penn)

2012-04-02

252

Mechanical properties of kenaf bast and core fibre reinforced unsaturated polyester composites  

NASA Astrophysics Data System (ADS)

Kenaf fibre has high potential to be used for composite reinforcement in biocomposite material. It is made up of an inner woody core and an outer fibrous bark surrounding the core. The aim of this study was to compare the mechanical properties of short kenaf bast and core fibre reinforced unsaturated polyester composites with varying fibre weight fraction i.e. 0%, 5%, 10%, 20%, 30% and 40%. The compression moulding technique was used to prepare the composite specimens for tensile, flexural and impact tests in accordance to the ASTM D5083, ASTM D790 and ASTM D256 respectively. The overall results showed that the composites reinforced with kenaf bast fibre had higher mechanical properties than kenaf core fibre composites. The results also showed that the optimum fibre content for achieving highest tensile strength for both bast and core fibre composites was 20%wt. It was also observed that the elongation at break for both composites decreased as the fibre content increased. For the flexural strength, the optimum fibre content for both composites was 10%wt while for impact strength, it was at 10%wt and 5%wt for bast and core fibre composites respectively.

Ishak, M. R.; Leman, Z.; Sapuan, S. M.; Edeerozey, A. M. M.; Othman, I. S.

2010-05-01

253

Hydrophilic Polyester Microspheres: Effect of Molecular Weight and Copolymer Composition on Release of BSA  

PubMed Central

ABSTRACT Purpose To study the release of a model protein, bovine serum albumin (BSA), from microspheres of an hydroxylated aliphatic polyester, poly(lactic-co-hydroxymethyl glycolic acid) (PLHMGA). Methods BSA-loaded microspheres were prepared by a double emulsion solvent evaporation method. The effect of copolymer composition and the molecular weight of the copolymer on in vitro release and degradation were studied. The integrity of the released BSA was studied by fluorescence spectroscopy and size exclusion chromatography (SEC). Results Microspheres prepared from PLHMGA with 50% hydroxymethyl glycolic acid (HMG) showed a burst release followed by a sustained release in 5–10 days. PLHMGA microspheres prepared from a copolymer with 35% and 25% HMG showed a sustained release of BSA up to 80% for 30 and 60 days, respectively. The release of BSA was hardly affected by the molecular weight of the polymer. Fluorescence spectroscopy and SEC showed that the released BSA preserved its structural integrity. Microspheres were fully degradable, and the degradation time increased from ~20 days to 60 days when the HMG content decreased from 50% to 25%. Conclusions Taking the degradation and release data together, it can be concluded that the release of BSA from PLHMGA microspheres is governed by degradation of the microspheres. PMID:20602152

Ghassemi, Amir H.; van Steenbergen, Mies J.; Talsma, Herre; van Nostrum, Cornelus F.; Crommelin, Daan J. A.

2010-01-01

254

Magnesium coated bioresorbable phosphate glass fibres: investigation of the interface between fibre and polyester matrices.  

PubMed

Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg(2+) in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM). The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM) and X-ray diffraction (XRD) analysis, respectively. The roughness of the coatings was seen to increase from 40 ± 1?nm to 80 ± 1?nm. The mechanical properties (tensile strength and modulus) of fibre with coatings decreased with increased magnesium coating thickness. PMID:24066297

Liu, Xiaoling; Grant, David M; Parsons, Andrew J; Harper, Lee T; Rudd, Chris D; Ahmed, Ifty

2013-01-01

255

Development of Composite Porous Scaffolds Based on Collagen and Biodegradable Poly(ester urethane)urea  

PubMed Central

Our objective in this work was to develop a flexible, biodegradable scaffold for cell transplantation that would incorporate a synthetic component for strength and flexibility and type I collagen for enzymatic lability and cytocompatibility. A biodegradable poly(ester urethane)urea was synthesized from poly(caprolactone), 1,4-diisocyanatobutane, and putrescine. Using a thermally induced phase separation process, porous scaffolds were created from a mixture containing this polyurethane and 0%, 10%, 20%, or 30% type I collagen. The resulting scaffolds were found to have open, interconnected pores (from 7 to >100 um) and porosities from 58% to 86% depending on the polyurethane/collagen ratio. The scaffolds were also flexible with breaking strains of 82–443% and tensile strengths of 0.97–4.11 MPa depending on preparation conditions. Scaffold degradation was significantly increased when collagenase was introduced into an incubating buffer in a manner that was dependent on the mass fraction of collagen present in the scaffold. Mass losses could be varied from 15% to 59% over 8 weeks. When culturing umbilical artery smooth muscle cells on these scaffolds higher cell numbers were observed over a 4-week culture period in scaffolds containing collagen. In summary, a strong and flexible scaffold system has been developed that can degrade by both hydrolysis and collagenase degradation pathways, as well as support cell growth. This scaffold possesses properties that would make it attractive for future use in soft tissue applications where such mechanical and biological features would be advantageous. PMID:16826792

Guan, Jianjun; Stankus, John J.; Wagner, William R.

2010-01-01

256

Enzyme-catalyzed synthesis of unsaturated aliphatic polyesters based on green monomers from renewable resources.  

PubMed

Bio-based commercially available succinate, itaconate and 1,4-butanediol are enzymatically co-polymerized in solution via a two-stage method, using Candida antarctica Lipase B (CALB, in immobilized form as Novozyme® 435) as the biocatalyst. The chemical structures of the obtained products, poly(butylene succinate) (PBS) and poly(butylene succinate-co-itaconate) (PBSI), are confirmed by 1H- and 13C-NMR. The effects of the reaction conditions on the CALB-catalyzed synthesis of PBSI are fully investigated, and the optimal polymerization conditions are obtained. With the established method, PBSI with tunable compositions and satisfying reaction yields is produced. The 1H-NMR results confirm that carbon-carbon double bonds are well preserved in PBSI. The differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results indicate that the amount of itaconate in the co-polyesters has no obvious effects on the glass-transition temperature and the thermal stability of PBS and PBSI, but has significant effects on the melting temperature. PMID:24970176

Jiang, Yi; Woortman, Albert J J; van Ekenstein, Gert O R Alberda; Loos, Katja

2013-01-01

257

Low molecular weight PEI-appended polyesters as non-viral gene delivery vectors.  

PubMed

Routine clinical implementation of human gene therapy requires safe and efficient gene delivery methods. Linear biodegradable polyesters with carbon-carbon double bonds are prepared from unsaturated diacids and diols. Subsequent appending of low molecular weight PEI by Michael addition gives target cationic polymers efficiently. Agarose gel retardation and fluorescence quenching assays show that these materials have good DNA binding ability and can completely retard plasmid DNA at weight ratio of 0.8. The formed polyplexes have appropriate sizes around 275 nm and zeta-potential values about +20-35 mV. The cytotoxicities of these polymers assayed by MTT are much lower than that of 25 kDa PEI. In vitro transfection toward 7402, HEK293 and U-2OS cells show that polymer P1 may give dramatically higher transfection efficiency (TE) than 25 kDa PEI, especially in U-2OS cells, suggesting that such polymer might be promising non-viral gene vectors. PMID:24681389

Xun, Miao-Miao; Liu, Yan-Hong; Guo, Qian; Zhang, Ji; Zhang, Qin-Fang; Wu, Wan-Xia; Yu, Xiao-Qi

2014-05-01

258

Spectroscopic study on water diffusion in poly(ester urethane) block copolymer matrix.  

PubMed

The diffusion of water in a phase-separated biodegradable poly(ester urethane) shape-memory polymer with poly(epsilon-caprolactone) (PCL) as the soft segment was investigated using time-resolved FTIR-ATR. On the basis of the band fitting and water ordering in drawn films, the broad water band in the 3800-2800 cm(-1) region was decomposed into four bands located at 3620, 3510, 3400, and 3260 cm(-1), and the first two components at 3620 and 3510 cm(-1) were assigned to the vibrations of antisymmetric and symmetric stretching of water hydrogen bonded with the C=O group of the soft segment. The other two were associated with water bonded to the urethane hard segments in the forms of N-H:O-H:O=C bridge hydrogen bond and double hydrogen bonds with two C=O groups, respectively. Furthermore, band fitting and two-dimensional correlation analyses revealed that in the diffusion process, water first diffuses into the continuous soft-rich PCL phase and then into the hard-rich urethane domains, forming double hydrogen bonds with two C=O groups prior to the bridge hydrogen bond in the form of N-H:O-H:O=C. PMID:19894687

Wang, Wei; Jin, Ying; Su, Zhaohui

2009-12-01

259

Enzyme-Catalyzed Synthesis of Unsaturated Aliphatic Polyesters Based on Green Monomers from Renewable Resources  

PubMed Central

Bio-based commercially available succinate, itaconate and 1,4-butanediol are enzymatically co-polymerized in solution via a two-stage method, using Candida antarctica Lipase B (CALB, in immobilized form as Novozyme® 435) as the biocatalyst. The chemical structures of the obtained products, poly(butylene succinate) (PBS) and poly(butylene succinate-co-itaconate) (PBSI), are confirmed by 1H- and 13C-NMR. The effects of the reaction conditions on the CALB-catalyzed synthesis of PBSI are fully investigated, and the optimal polymerization conditions are obtained. With the established method, PBSI with tunable compositions and satisfying reaction yields is produced. The 1H-NMR results confirm that carbon-carbon double bonds are well preserved in PBSI. The differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results indicate that the amount of itaconate in the co-polyesters has no obvious effects on the glass-transition temperature and the thermal stability of PBS and PBSI, but has significant effects on the melting temperature. PMID:24970176

Jiang, Yi; Woortman, Albert J.J.; Alberda van Ekenstein, Gert O.R.; Loos, Katja

2013-01-01

260

Generation of conductivity through transfer charge properties, for polyesters and polyamides with characteristic functional groups  

NASA Astrophysics Data System (ADS)

Electro-optic properties of ?-conjugated polymers, as polysilylene; are associated with electron conjugation in the silicon atom, which allows a significant delocalization of electrons along of the chain. Thus, the conductivity is intimately connected to the mobility of charge carriers, which in turn depends on the structure and morphology of the system. We report the characterization of polyesters (PEFs) and polyamides (PAFs). Film thicknesses were obtained by ellipsometry. The vibration frequencies of the groups were determined by FT-IR and corroborated by Raman spectroscopy. Structural information was obtained from X-Ray diffraction (XRD). The structural and surface morphology were studied by scanning electron microscope (SEM). Electrical conductivity of the polymers was measured before and after exposure to iodine vapor, for films of different thicknesses. Morphological differentiation was studied by energy dispersive microscopy (EDX), showing a regular distribution of iodine within the polymer. Preliminary conductivity measurements showed adverse effects when oxidation of the polymer films is induced These effects are related to a certain grade of disorder within the system

Gonzalez, Carmen; Hernan Tagle, Luis; Terraza, Claudio A.; Barriga, Andres; Cabrera, A. L.; Volkmann, Ulrich G.

2011-03-01

261

Insulating epoxy/barite and polyester/barite composites for radiation attenuation.  

PubMed

A trial has been made to create insulating Epoxy/Barite (EP/Brt) (?=2.85 g cm(-3)) and Crosslinked Unsaturated Polyester/Barite (CUP/Brt) (?=3.25 g cm(-3)) composites with radiation attenuation and shielding capabilities. Experimental work regarding mechanical and physical properties was performed to study the composites integrity for practical applications. The properties were found to be reasonable. Radiation attenuation properties have been carried out using emitted collimated beam from a fission (252)Cf (100 µg) neutron source, and the neutron-gamma spectrometer with stilbene scintillator. The pulse shape discriminating (P.S.D) technique based on the zero cross-over method was used to discriminate between neutron and gamma-ray pulses. Thermal neutron fluxes, measured using the BF3 detector and thermal neutron detection system, were used to plot the attenuation relations. The fast neutron macroscopic effective removal cross-section ?R, gamma ray total attenuation coefficient µ and thermal neutron macroscopic cross-section ? have been evaluated. Theoretical calculations have been achieved using MCNP-4C2 code to calculate ?R, µ and ?. Also, MERCSF-N program was used to calculate macroscopic effective removal cross-section ?R. Measured and calculated results have been compared and were found to be in reasonable agreement. PMID:23722071

El-Sarraf, M A; El-Sayed Abdo, A

2013-09-01

262

Hyperbranched Polyester Hydrogels with Controlled Drug Release and Cell Adhesion Properties  

PubMed Central

Hyperbranched polyesters (HPE) have a high efficiency to encapsulate bioactive agents, including drugs, genes and proteins, due to their globe-like nanostructure. However, the use of these highly branched polymeric systems for tissue engineering applications has not been broadly investigated. Here, we report synthesis and characterization of photocrosslinkable HPE hydrogels with sustained drug release characteristics for cellular therapies. These HPE can encapsulate hydrophobic drug molecules within the HPE cavities, due to the presence of hydrophobic inner structure that is otherwise difficult to achieve in conventional hydrogels. The functionalization of HPE with photocrosslinkable acrylate moieties renders the formation of hydrogels with highly porous interconnected structure, and mechanically tough network. The compressive modulus of HPE hydrogels was tunable by changing the crosslinking density. The feasibility of using these HPE networks for cellular therapies was investigated by evaluating cell adhesion, spreading and proliferation on hydrogel surface. Highly crosslinked and mechanically stiff HPE hydrogels have higher cell adhesion, spreading, proliferation compared to soft and complaint HPE hydrogels. Overall, we showed that hydrogels made from HPE could be used for biomedical applications that require control cell adhesion and control release of hydrophobic clues. PMID:23394067

Zhang, Hongbin; Patel, Alpesh; Gaharwar, Akhilesh K.; Mihaila, Silvia M.; Iviglia, Giorgio; Mukundan, Shilpaa; Bae, Hojae; Yang, Huai; Khademhosseini, Ali

2013-01-01

263

Predicting the Thermal Conductivity of AlSi/Polyester Abradable Coatings: Effects of the Numerical Method  

NASA Astrophysics Data System (ADS)

The final target of this study is to achieve a better understanding of the behavior of thermally sprayed abradable seals such as AlSi/polyester composites. These coatings are used as seals between the static and the rotating parts in aero-engines. The machinability of the composite coatings during the friction of the blades depends on their mechanical and thermal effective properties. In order to predict these properties from micrographs, numerical studies were performed with different software packages such as OOF developed by NIST and TS2C developed at the UTBM. In 2008, differences were reported concerning predictions of effective thermal conductivities obtained with the two codes. In this article, a particular attention was paid to the mathematical formulation of the problem. In particular, results obtained with a finite difference method using a cell-centered approach or a nodal formulation allow explaining the discrepancies previously noticed. A comparison of the predictions of the computed effective thermal conductivities is thus proposed. This study is part of the NEWAC project, funded by the European Commission within the 6th RTD Framework programm (FP6).

Bolot, Rodolphe; Seichepine, Jean-Louis; Qiao, Jiang Hao; Coddet, Christian

2011-01-01

264

Biodegradable polyester-based microcarriers with modified surface tailored for tissue engineering.  

PubMed

Microcarriers have been proposed in tissue engineering, namely for bone, cartilage, skin, vascular, and central nervous system. Although polyester-based microcarriers have been already used for this purpose, their surface properties should be improved to provide better cell growth. The goal of this study was to prepare microbeads based on poly(d,l-lactide) acid, poly(l-lactide) acid, and to study cell behavior (adhesion, spreading, growth, and proliferation) in function of microbead topography and surface chemistry. To improve L-929 fibroblasts adhesion, microbead surface has been modified with three polycations: chitosan, poly(2-dimethylamino ethylmethacrylate) (PDMAEMA), or chitosan-g-oligolactide copolymer (chit-g-OLA). Although modification of the microbead surface with chitosan and PDMAEMA was performed through physical adsorption on the previously prepared microbeads, chit-g-OLA copolymer was introduced directly during microbead processing. This simple approach (1) bypass the use of an emulsifier (polyvinyl alcohol, PVA); (2) avoid surface "contamination" with PVA molecules limiting a control of the surface characteristics. In vitro study of the growth of mouse fibroblasts on the microbeads showed that both surface topography and chemistry affected cell attachment, spreading, and proliferation. Cultivation of L-929 fibroblasts for 7 days resulted in the formation of a 3D cell-scaffold network. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 939-948, 2015. PMID:24832052

Privalova, A; Markvicheva, E; Sevrin, Ch; Drozdova, M; Kottgen, C; Gilbert, B; Ortiz, M; Grandfils, Ch

2015-03-01

265

Polyester modification of the mammalian TRPM8 channel protein: Implications for structure and function  

PubMed Central

SUMMARY The TRPM8 ion channel is expressed in sensory neurons and is responsible for sensing environmental cues such as cold temperatures and chemical compounds, including menthol and icilin. The channel functional activity is regulated by various physical and chemical factors, and is likely to be pre-conditioned by its molecular composition. Our studies indicate that TRPM8 channel forms a structural-functional complex with the polyester, poly-(R)-3hydroxybutyrate (PHB). We identified by mass spectrometry a number of PHB-modified peptides in the N-terminus of the TRPM8 protein and in its extracellular S3–S4 linker. Removal of PHB by enzymatic hydrolysis, and site-directed mutagenesis of both the serine residues that serve as covalent anchors for PHB and adjacent hydrophobic residues that interact with the methyl groups of the polymer, resulted in significant inhibition of TRPM8 channel activity. We conclude that the TRPM8 channel undergoes post-translational modification by PHB and that this modification is required for its normal function. PMID:23850286

Bikard, Yann; Chen, Wei; Liu, Tong; Li, Hong; Jendrossek, Dieter; Cohen, Alejandro; Pavlov, Evgeny; Rohacs, Tibor; Zakharian, Eleonora

2013-01-01

266

Cure Monitoring of an Unsaturated Polyester Resin Using Near-Infrared and Fluorescence Spectroscopies  

NASA Astrophysics Data System (ADS)

The applicability of both near-infrared (NIR) and fluorescence spectroscopy for the purpose of cure monitoring an unsaturated polyester (UPE) resin was investigated. Based on standard reference mixtures, peak assignments in the NIR region of the spectrum were made. It was determined that the peak at 1629 nm was due to the first overtone band of RHC=CH2 stretching modes in styrene, while a combination of RHC=CHR and -C=C- stretching modes in diethyl fumarate were responsible for the peak observed at 2087 nm. NIR spectra of the UPE resin during isothermal cure at 75 C exhibited decreases in peak absorbance at 1629 and 2087 nm due to conversion of styrene and vinylene bonds, respectively. Conversion of styrene and vinylene with time calculated using NIR spectra showed similar trends found with FTIR analysis throughout the entire conversion range. Fluorescence spectroscopy was used to monitor the isothermal curing reaction of the UPE resin by exciting styrene at 250 nm. Emission intensity at ca. 306 nm remained unchanged for the initial 60-80 minutes then increased with cure time due to a reduced self-quenching effect as cure proceeded. The increase in fluorescence intensity was concurrent with an increase in styrene conversion up to 93% styrene conversion.

Sung, Chong S. P.; Grunden, Bradley L.

1998-03-01

267

Effect of hydroxyapatite on the biodegradation and biomechanical stability of polyester nanocomposites for orthopaedic applications.  

PubMed

The effect of hydroxyapatite (HAP) on the performance of nanocomposites of an unsaturated polyester, i.e., hydroxy-terminated high molecular weight poly(proplyene fumarate) (HT-PPFhm), was investigated. A thermoset nanocomposite was prepared with nanoparticles of calcined HAP (<100 nm, rod-like shape, filler content 30 wt.%), HT-PPFhm and N-vinyl pyrrolidone, dibenzoyl peroxide and N,N-dimethyl aniline. Two more nanocomposites were prepared with precipitated HAP nanoparticles (<100 nm rod-like shape) and commercially available HAP nanoparticles (<200 nm spherical shape), respectively. Calcined HAP nanoparticles resulted in very good crosslinking in the resin matrix with high crosslinking density and interfacial bonding with the polymer, owing to the rod-like shape of the nanoparticles; this gave improved biomechanical strength and modulus and also controlled degradation of the nanocomposite for scaffold formation. The tissue compatibility and osteocompatibility of the nanocomposite containing calcined HAP nanoparticles was evaluated. The tissue compatibility was studied by intramuscular implantation in a rabbit animal model for 3 months as per ISO standard 10993/6. The in vivo femoral bone repair was also carried out in the rabbit animal model as per ISO standard 10993/6. The nanocomposite containing calcined HAP nanoparticles is both biocompatible and osteocompatible. PMID:19788944

Jayabalan, M; Shalumon, K T; Mitha, M K; Ganesan, K; Epple, M

2010-03-01

268

Analysis and aging of unsaturated polyester resins in contemporary art installations by NMR spectroscopy.  

PubMed

Two original art installations constructed from unsaturated polyester resins (UPR) and four different reference UPR products (before and after UVB aging) were analyzed by high-resolution 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. Breaking strain studies were also conducted for the four UPR model products before and after different aging procedures (moisture, UVB exposure, melt/freeze). NMR analysis of the chemical composition of the UPR resin extracts showed they contain several low MW organic compounds and oligomers rich in polar -OH groups that play a significant role in the degradation behavior of the composite UPR materials. Statistical analysis of the NMR compositional data showed that styrene and benzaldehyde contents can be used to differentiate between fresh and aged UPR samples. The phthalate and propylene glycol unit speciation (esterified, primary or secondary -OH) of the extracts provided evidence that UPR resin C was used in the construction of the two art installations, and direct comparison of (1)H and (13)C NMR spectra verified this compositional similarity. UPR resin C was shown by both NMR and breaking strain studies to be the reference UPR most susceptible to degradation by different aging procedures, a characteristic attributed to the lower styrene content of resin C. PMID:20922516

Stamatakis, Georgios; Knuutinen, Ulla; Laitinen, Kai; Spyros, Apostolos

2010-12-01

269

Crosslinking of a polyester resin in the heated plain sheet copper mould  

NASA Astrophysics Data System (ADS)

The crosslinking of the unsaturated polyester was studied by using experiments and a model of the process. The kinetic parameters were calculated from the heat flux time curves obtained by differential scanning calorimetry (DSC, Netzsch Simultaneous Thermal Analyser DSC 200), working in DSC (dynamic) mode. The temperature time histories were studied in plain sheet copper mould. The mathematical model was constructed by taking into account the heat transferred by conduction through the resin, as well as the kinetics of heat generated by the crosslinking reaction. The contributions to the rise in temperature from heat conduction and chemical reaction are different in different parts of the composite, and can explain the temperature-, or degree of crosslinking (DOC) time histories. By considering temperature time histories developed within the sample, more extensive knowledge of the process can be obtained. The effect of the heat transfer by conduction through the composite as well as the internal heat generated by the cure reaction is clearly shown, despite the complexity of the process. Finally, good agreement between experimental data and predicted mathematical model of the crosslinking process in plane sheet mould was shown.

Kosar, Vanja; Gomzi, Zoran

2008-04-01

270

Degradation of polyester polyurethane by a newly isolated soil bacterium, Bacillus subtilis strain MZA-75.  

PubMed

A polyurethane (PU) degrading bacterial strain MZA-75 was isolated from soil through enrichment technique. The bacterium was identified through 16S rRNA gene sequencing, the phylogenetic analysis indicated the strain MZA-75 belonged to genus Bacillus having maximum similarity with Bacillus subtilis strain JBE0016. The degradation of PU films by strain MZA-75 in mineral salt medium (MSM) was analyzed by scanning electron microscopy (SEM), fourier transform infra-red spectroscopy (FT-IR) and gel permeation chromatography (GPC). SEM revealed the appearance of widespread cracks on the surface. FTIR spectrum showed decrease in ester functional group. Increase in polydispersity index was observed in GPC, which indicates chain scission as a result of microbial treatment. CO2 evolution and cell growth increased when PU was used as carbon source in MSM in Sturm test. Increase in both cell associated and extracellular esterases was observed in the presence of PU indicated by p-Nitrophenyl acetate (pNPA) hydrolysis assay. Analysis of cell free supernatant by gas chromatography-mass spectrometry (GC-MS) revealed that 1,4-butanediol and adipic acid monomers were produced. Bacillus subtilis strain MZA-75 can degrade the soft segment of polyester polyurethane, unfortunately no information about the fate of hard segment could be obtained. Growth of strain MZA-75 in the presence of these metabolites indicated mineralization of ester hydrolysis products into CO2 and H2O. PMID:23536219

Shah, Ziaullah; Krumholz, Lee; Aktas, Deniz Fulya; Hasan, Fariha; Khattak, Mutiullah; Shah, Aamer Ali

2013-11-01

271

Framework effect of amphiphilic polyesters on their molecular movement and protein adsorption-resistance properties.  

PubMed

Surface chemical characteristics of biomedical polymers, which are determined by the migration and rearrangement of polymeric chains, play an important role in the protein adsorption. In this work, the relationship between the architectures of amphiphilic polyesters and their protein adsorption resistance was investigated. Three poly (?-caprolactone)s containing sulfobetaines (PCL-b-PDEAS) segments with linear, four arms and six arms star-shaped architectures were synthesized with the combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). The structures of the amphiphiles were confirmed by (1)H NMR and FTIR. Water contact angles (WCA) and X-ray photoelectron spectroscopy (XPS) were used to study the surface properties of the amphiphilic copolymer films. The water contact angles were decreased due to the surface migration of hydrophilic segments. Transmission electron microscopy (TEM) displayed the occurrence of microphase separation phenomena for PCL-b-PDEAS above glass transition temperature (Tg). The results showed that the hydrophilic segments in the copolymers would migrate to the surface of the films, which resulted in the surface more hydrophilic to resist protein adsorption. The adsorption of both fibrinogen (Fg) and bovine serum albumin (BSA) were studied. The results showed that protein adsorption was depended on not only the hydrophilic chain migration but also the shape of proteins. PMID:25499227

Cao, Jun; Cheng, Furong; Cao, Huan; Lu, Aijing; Cai, Mengtan; Chen, Yuanwei; He, Bin; Gu, Zhongwei; Luo, Xianglin

2015-01-01

272

Euphopubescenol and euphopubescene, two new jatrophane polyesters, and lathyrane-type diterpenes from Euphorbia pubescens.  

PubMed

The structures of euphopubescenol and euphopubescene, two new macrocyclic jatrophane diterpene polyesters, isolated from the whole dried plant of Euphorbia pubescens, were established as 5alpha,8alpha,15beta-triacetoxy-3alpha-benzoyloxy -4alpha-hydroxy -9,14-dioxo-13beta H-jatropha-6(17),11 E-diene ( 1) and 3beta,7beta,8beta,9alpha,14alpha,15beta-hexaacetoxy-2beta H-jatropha-5 E,11 E-diene ( 2) by 1D- and 2D-NMR (COSY, HMQC, HMBC and NOESY), IR, EI-MS and EI-FTICR-MS. Two known lathyrane derivatives, jolkinol A ( 3) and jolkinol A ( 4), whose (13)C-NMR spectra were assigned, were also isolated. Compounds 1 - 3 have been evaluated for their ability to inhibit the in vitro growth of three human tumour cell lines representing different tumour types, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and SF-268 (CNS cancer). They inhibited both MCF-7 and NCI-H460 cell lines, with GI50 values ranging between 40.9 microM and 95.3 microM, but were found to be ineffective as growth inhibitors of the SF-268 cell line. PMID:15114502

Valente, Cláudia; Pedro, Madalena; Ascenso, José R; Abreu, Pedro M; Nascimento, Maria São; Ferreira, Maria-José U

2004-03-01

273

Biostability and biocompatibility of poly(ester urethane)-gold nanocomposites.  

PubMed

Nanocomposites from a polyester-type water-borne polyurethane (PU) containing different amounts (17.4-174 ppm) of gold (Au) nanoparticles (approximately 5 nm) were prepared. A previous study has shown that the Au nanoparticles could induce surface morphological transformations in the PU (e.g. the mesophase transition from hard lamellae to soft micelles), which modify the physicochemical properties of the PU as well as the fibroblast response to the PU. The current study focused on the biostability and biocompatibility of the nanocomposites. The nanocomposites were characterized by transmission electron microscopy and X-ray photoelectron spectroscopy, and their oxidative stability and free radical scavenging ability were tested. The inflammatory response was evaluated by monocyte activation in vitro and rat subcutaneous implantation in vivo. It was found that the nanocomposites containing 43.5-65 ppm of Au had the least monocyte activation and tissue reactions. PU and the nanocomposites were rather resistant to oxidative degradation in vitro and biodegradation in vivo. The nanocomposites exhibited greater free radical scavenging abilities than the original PU. Based on the above results, the significantly enhanced biocompatibility of the PU-Au nanocomposites with 43.5-65 ppm of gold over the original PU appeared to be a result of the extensively modified surface morphology and greater free radical scavenging ability, instead of due to the difference in biostability. PMID:18657493

Hsu, Shan-hui; Tang, Cheng-Ming; Tseng, Hsiang-Jung

2008-11-01

274

Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices  

PubMed Central

Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM). The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM) and X-ray diffraction (XRD) analysis, respectively. The roughness of the coatings was seen to increase from 40 ± 1?nm to 80 ± 1?nm. The mechanical properties (tensile strength and modulus) of fibre with coatings decreased with increased magnesium coating thickness. PMID:24066297

Liu, Xiaoling; Grant, David M.; Parsons, Andrew J.; Harper, Lee T.; Rudd, Chris D.; Ahmed, Ifty

2013-01-01

275

Antimicrobial electrospun nanofibers of cellulose acetate and polyester urethane composite for wound dressing.  

PubMed

In this study, a series of nanofibrous membranes were prepared from cellulose acetate (CA) and polyester urethane (PEU) using coelectrospinning or blend-electrospinning. The drug release, in vitro antimicrobial activity and in vivo wound healing performance of the nanofiber membranes were evaluated for use as wound dressings. To prevent common clinical infections, an antimicrobial agent, polyhexamethylene biguanide (PHMB) was incorporated into the electrospun fibers. The presence of CA in the nanofiber membrane improved its hydrophilicity and permeability to air and moisture. CA fibers became slightly swollen upon contacting with liquid phase. CA not only increased the liquid uptake but also created a moist environment for the wound, which accelerated wound recovery. PHMB release dynamics of the membranes was controlled by the structure and component ratios of the membranes. The lower ratio of CA: PEU helped to preserve the physical and thermal properties of the membranes, and also reduced the burst release effectively and slowed down diffusion of PHMB during in vitro tests. The controlled-diffusion membranes exerted long-term antimicrobial effect for wound healing. PMID:22692845

Liu, Xin; Lin, Tong; Gao, Yuan; Xu, Zhiguang; Huang, Chen; Yao, Gang; Jiang, Linlin; Tang, Yanwei; Wang, Xungai

2012-08-01

276

New polymorphous computing fabric.  

SciTech Connect

This paper introduces a new polymorphous computing Fabric well suited to DSP and Image Processing and describes its implementation on a Configurable System on a Chip (CSOC). The architecture is highly parameterized and enables customization of the synthesized Fabric to achieve high performance for a specific class of application. For this reason it can be considered to be a generic model for hardware accelerator synthesis from a high level specification. Another important innovation is the Fabric uses a global memory concept, which gives the host processor random access to all the variables and instructions on the Fabric. The Fabric supports different computing models including MIMD, SPMD and systolic flow and permits dynamic reconfiguration. We present a specific implementation of a bank of FIR filters on a Fabric composed of 52 cells on the Altera Excalibur ARM running at 33 MHz. The theoretical performance of this Fabric is 1.8 GMACh. For the FIR application we obtain 1.6 GMAC/s real performance. Some automatic tools have been developed like the tool to provide a host access utility and assembler.

Wolinski, C. (Christophe); Gokhale, M. (Maya); McCabe, K. P. (Kevin P.)

2002-01-01

277

Biologically inspired digital fabrication  

E-print Network

Objects and systems in nature are models for the practice of sustainable design and fabrication. From trees to bones, natural systems are characterized by the constant interplay of creation, environmental response, and ...

Han, Sarah (Sarah J.)

2013-01-01

278

Other Fabric Structures  

NASA Technical Reports Server (NTRS)

Architects, engineers and building owners are turning increasingly to fabric structures because of their aesthetic appeal, relatively low initial cost, low maintenance outlays, energy efficiency and good space utilization. Several examples are shown.

1982-01-01

279

Structural Fabrication I Syllabus  

NSDL National Science Digital Library

This pdf contains a syllabus for a first course on structural fabrication as part of the Aerospace Technology Program. Topics include trigonometry, machine tools, blueprints, metal working, aerospace fasteners, and sheet metal repair.

2011-08-03

280

Contribution To Degradation Study, Behavior Of Unsaturated Polyester Resin Under Neutron Irradiation  

NASA Astrophysics Data System (ADS)

Applications of unsaturated polyester thermosetting resins are numerous in construction sector, in transport, electric spare parts manufactures, consumer goods, and anticorrosive materials. This survey reports the effect of thermosetting polymer degradation (unsaturated polyester): degradation by neutrons irradiation. In order to evaluate the deterioration of our material, some comparative characterizations have been done between standard samples and damaged ones. Scanning electron microscopy (SEM), ultrasonic scanning, hardness test (Shore D) are the techniques which have been used. The exposure to a neutrons flux is carried out in the column of the nuclear research reactor of Draria (Algiers-Algeria). The energetic profile of the incidental fluxes is constituted of fast neutrons (?R = 3.1012n.cm-2.s-1, E = 2 Mev) of thermal neutrons (?TH = 1013n.cm-2.s-1; E = 0.025 ev) and epithermal neutrons (?epi = 7.1011 n.cm-2.s-1; E>4,9 ev). The received dose flow is 0,4 Kgy. We notice only a few scientific investigations can be found in this field. In comparison with the standard sample (no exposed) it is shown that the damage degree is an increasing process with the exposure. Concerning the description of irradiation effects on polymers, we can advance that several reactions are in competition : reticulation, chain break, and oxidation by radical mechanism. In our case the incidental particle of high energy fast neutrons whose energy is greater or equal to 2 Mev, is braked by the target with a nuclear shock during which the incidental particle transmits a part of its energy to an atom. If the energy transfer is sufficient, the nuclear shock permits to drive out an atom of its site the latter will return positioning interstitially, the energy that we used oversteps probably the energy threshold (displacement energy). This fast neutrons collision with target cores proceeds to an indirect ionization by the preliminary creation of excited secondary species that will generate ionization. Scanning electron microscopy (SEM) performed with an acceleration tension of 0,7 kV shows clearly the caused damage. This observation seems to indicate the presence of major chain breaks for the sample bombarded during 90 minutes. Let us note that the presence of benzenic cores improves behavior toward radiations indeed the chemical function recognized as the most stable to radiations is the aromatic ring. In order to value the rigidity of our material we have determined the Young's modulus . The values are 7.17, 7.60, 8.39 and 8.96 Gpa respectively for blank samples, 30, 60 and 90 minutes exposure ones. Thus, we remark an increase of Young's modulus that can be interpreted in terms of reticulation, provided to use the level of irradiation dose.

Abellache, D.; Lounis, A.; Taïbi, K.

2010-01-01

281

Effects of Porous Polystyrene Resin Parameters on Candida antarctica Lipase B Adsorption, Distribution, and Polyester Synthesis Activity  

SciTech Connect

Polystyrene resins with varied particle sizes (35 to 350-600 {mu}m) and pore diameters (300-1000 {angstrom}) were employed to study the effects of immobilization resin particle size and pore diameter on Candida antarctica Lipase B (CALB) loading, distribution within resins, fraction of active sites, and catalytic properties for polyester synthesis. CALB adsorbed rapidly (saturation time {<=}4 min) for particle sizes 120 {mu}m (pore size = 300 {angstrom}). Infrared microspectroscopy showed that CALB forms protein loading fronts regardless of resin particle size at similar enzyme loadings ({approx}8%). From the IR images, the fractions of total surface area available to the enzyme are 21, 33, 35, 37, and 88% for particle sizes 350-600, 120, 75, 35 {mu}m (pore size 300 {angstrom}), and 35 {mu}m (pore size 1000 {angstrom}), respectively. Titration with methyl p-nitrophenyl n-hexylphosphate (MNPHP) showed that the fraction of active CALB molecules adsorbed onto resins was {approx}60%. The fraction of active CALB molecules was invariable as a function of resin particle and pore size. At {approx}8% (w/w) CALB loading, by increasing the immobilization support pore diameter from 300 to 1000 {angstrom}, the turnover frequency (TOF) of {var_epsilon}-caprolactone ({var_epsilon}-CL) to polyester increased from 12.4 to 28.2 s{sup -1}. However, the {var_epsilon}-CL conversion rate was not influenced by changes in resin particle size. Similar trends were observed for condensation polymerizations between 1,8-octanediol and adipic acid. The results herein are compared to those obtained with a similar series of methyl methacrylate resins, where variations in particle size largely affected CALB distribution within resins and catalyst activity for polyester synthesis.

Chen,B.; Miller, M.; Gross, R.

2007-01-01

282

Superabsorbent Multilayer Fabric  

NASA Technical Reports Server (NTRS)

Material contains gel-forming polymer and copolymer that absorb from 70 to 200 times their weight of liquid. Superabsorbent Polymer and Copolymer form gels to bind and retain liquid in multiply fabric. Until reaction between liquid and absorbent masses forms gel, backing layer retains liquids within fabric; also allows material to "breathe." Possible applications include baby diapers, female hygiene napkins, and hospital bedpads. Might also have uses in improvement of dry soil.

Coreale, J. V.; Dawn, F. S.

1982-01-01

283

Fabricated torque shaft  

DOEpatents

A fabricated torque shaft is provided that features a bolt-together design to allow vane schedule revisions with minimal hardware cost. The bolt-together design further facilitates on-site vane schedule revisions with parts that are comparatively small. The fabricated torque shaft also accommodates stage schedules that are different one from another in non-linear inter-relationships as well as non-linear schedules for a particular stage of vanes.

Mashey, Thomas Charles (Anderson, SC)

2002-01-01

284

Fabrication of High T  

Microsoft Academic Search

Metal-clad high-T_{rm c} superconductor wires have been fabricated by conventional hot extrusion and wire drawing techniques. The fabrication processes which were used influenced the microstructure which, in turn, governed the superconducting properties of metal-clad Y-Ba-Cu-O (YBCO) and Bi-Pb-Sr-Ca-Cu-O (BPSCCO) superconductors. The ability to form these materials into long thin wires and the electrical properties of the wires were assessed. Extruded

Miles Hyam Apperley

1992-01-01

285

Development and Evaluation of Novel Coupling Agents for Kenaf-Fiber-Reinforced Unsaturated Polyester Composites  

NASA Astrophysics Data System (ADS)

Natural fibers are gaining popularity as reinforcement materials for thermoset resins over the last two decades. Natural fibers are inexpensive, abundant, renewable and environmentally friendly. Kenaf fibers are one of the natural fibers that can potentially be used for reinforcing unsaturated polyester (UPE). As a polymer matrix, UPE enjoys a 40% market share of all the thermoset composites. This widespread application is due to many favorable characteristics including low cost, ease of cure at room temperature, ease of molding, a good balance of mechanical, electrical and chemical properties. One of the barriers for the full utilization of the kenaf fiber reinforced UPE composites, however, is the poor interfacial adhesion between the natural fibers and the UPE resins. The good interfacial adhesion between kenaf fibers and UPE matrix is essential for generating the desired properties of kenaf-UPE composites for most of the end applications. Use of a coupling agent is one of the most effective ways of improving the interfacial adhesion. In this study, six novel effective coupling agents were developed and investigated for kenaf-UPE composites: DIH-HEA, MFA, NMA, AESO-DIH, AESO-MDI, and AESO-PMDI. All the coupling agents were able to improve the interfacial adhesion between kanaf and UPE resins. The coupling agents were found to significantly enhance the flexural properties and water resistance of the kenaf-UPE composites. Fourier transform infrared spectroscopy (FTIR) confirmed all the coupling agents were covalently bonded onto kenaf fibers. Scanning electron microscopy (SEM) images of the composites revealed the improved interfacial adhesion between kanaf fibers and UPE resins.

Ren, Xiaofeng

286

Phase Transitions, Crystallization Behaviors and Structure of a Nonracemic Chiral Main-Chain Liquid Crystalline Polyester  

NASA Astrophysics Data System (ADS)

A nonracemic chiral main-chain liquid crystalline (LC) polyester [PET(R*)-7] has been synthesized using condensation reaction of an AB type monomer. Multiple phase transitions have been found during cooling and heating at different rates in differential scanning calorimetry measurements. Wide-angle X-ray diffraction (WAXD) experiments have shown that the phase transition swquence is from a highly ordered smectic phase -SmC* (139 °C) - SmA* (199 °C) TGBA ( 206 °C) isotropic with increasing temperature. Flat-on and twisted helical single crystals can be grown thermotropically from the LC state. Both types of crystals possess the identical monoclinic unit cell: a = 1.04 nm, b = 0.450 nm, c= 5.59 nm and g = 84.2 °. All helical crystals show a right-hand twist with pitch lengths of ranging between 0.5 - 5 mm. These single crystals can also be obtained by evaporating solvent from solution. PET(R*)-7 crystallizes much faster in its orientated form. It has been found that the orientation of crystals can be manipulated by the nature of phase from which they grow. The c-axis of crystals is along the fiber axis when crystallization occurs in the SmA* phase, while the c-axis of crystals is along the direction of the SmC* layer normal when crystallization takes place in the SmC* phase. An interesting observation is that macroscopic LC quasi-monodomains can be obtained by applying a mechanical external field. Detailed WAXD results indicate that they are SmC* quasi-monodomains. A quasi-monodomain can crystallize into a single-crystal-like structure.

Jin, Shi; Bai, Feng; Li, Christopher Y.; Harris, Frank W.; Cheng, S. Z. D.

2002-03-01

287

In-source analysis of radiation curing of unsaturated polyester resin by charging current technique  

NASA Astrophysics Data System (ADS)

The dielectric and conductive properties of unsaturated polyester (UP) resins undergo significant changes in the course of crosslinking reaction. In-source radiation curing of UP resins was studied by combining dielectric, thermal and charging current analyses. Dielectric permittivity (by stepwise changing of frequency) and charging current were measured in the course of cobalt-60 ?-irradiation at constant temperatures. The exothermic reaction could be monitored by differential thermal analysis (DTA), while the observed change of dielectric permittivity can show how the dielectric relaxation time distribution shifted through the experimental window represented by reaction temperature and by frequency range of dielectric spectrometer. The decrease in dielectric permittivity and in charging current may be mainly associated with the partial immobilization of permanent carbonyl and hydroxyl dipoles attached to the oligoester chain. The measurements of charging properties of UP resins during the curing seems very promising due to the ease with which the relaxation parameters and essential information on the molecular interactions and mobility can be derived. The electrical properties of UP resins are mainly determined by inter- and intramolecular hydrogen bonds. The shape of the charging current spectra during the curing of UP resins showed a heterogeneous nature of vitrification process. The results show that two relaxations occur: the first one is attributed to the increase in viscosity of liquid phase as oligoester chains are crosslinked prior to the gelation, and the second one to the further crosslinking in the gel phase, resulting in the vitrification of the system. The characteristic times to gelation and vitrification of UP resins in the course of radiation isothermal curing are decreasing functions of reaction temperature.

Jel?i?, Ž.; Ranogajec, F.; Puci?-Mili?i?, I.

288

Fabric space radiators  

SciTech Connect

Future Air Force space missions will require thermal radiators that both survive in the hostile space environment and stow away for minimal bulk during launch. Advances in all aspects of radiator design, construction, and analysis will be necessary to enable such future missions. Currently, the best means for obtaining high strength along with flexibility is through structures known as fabrics. The development of new materials and bonding techniques has extended the application range of fabrics into areas traditionally dominated by monolithic and/or metallic structures. Given that even current spacecraft heat rejection considerations tend to dominate spacecraft design and mass, the larger and more complex designs of the future face daunting challenges in thermal control. Ceramic fabrics bonded to ultra-thin metal liners (foils) have the potential of achieving radiator performance levels heretofore unattainable, and of readily matching the advances made in other branches of spacecraft design. The research effort documented here indicates that both pumped loops and heat pipes constructed in ceramic fabrics stand to benefit in multiple ways. Flexibility and low mass are the main advantages exhibited by fabric radiators over conventional metal ones. We feel that fabric radiators have intrinsic merits not possessed by any other radiator design and need to be researched further. 26 refs., 16 figs., 17 tabs.

Antoniak, Z.I.; Krotiuk, W.J.; Webb, B.J.; Prater, J.T.; Bates, J.M.

1988-01-01

289

The behavior of MEKO-blocked isocyanate compounds in aluminum flake pigmented, polyester–polyurethane can coating systems  

Microsoft Academic Search

Information is given concerning the curing characteristics of polyester–polyurethane (PEPU)-based food can coatings and the\\u000a analysis of the free isocyanate by-products. The behavior of a methyl ethyl ketoxime (MEKO)-blocked isocyanate on heating\\u000a was studied using thermal analytical techniques. Following this, the curing behavior of a PEPU-based can coating (PEPU01 that\\u000a contained an aluminum flake pigment) and the MEKO-blocked isocyanate was

C. Jiang; M. Driffield; E. L. Bradley; L. Castle; P. K. T. Oldring; J. T. Guthrie

2010-01-01

290

Electrochemical identification of anthraquinone-based dyes in solid microsamples by square wave voltammetry using graphite/polyester composite electrodes.  

PubMed

An electrochemical method for identifying anthraquinone-type dyes in microsamples from works of art, based in the voltammetry of microparticles approach, is reported. Upon attachment onto graphite/polyester composite electrodes, natural pigments aloe, henna, cochineal red, madder lake, kermes, shellac, and alizarin and purpurin taken as reference materials can be identified from their square wave voltammetric profiles in MeCN (0.10 mol L(-1) Bu(4)NPF(6)) and aqueous (0.25 mol L(-1) acetic acid+0.25 mol L(-1) sodium acetate) electrolytes. PMID:12733034

Doménech-Carbó, A; Doménech-Carbó, M T; Saurí-Peris, M C; Gimeno-Adelantado, J V; Bosch-Reig, F

2003-04-01

291

Final Report: Development of Renewable Microbial Polyesters for Cost Effective and Energy- Efficient Wood-Plastic Composites  

SciTech Connect

In this project, we proposed to produce wood fiber reinforced thermoplastic composites (WFRTCs) using microbial thermoplastic polyesters in place of petroleum-derived plastic. WFRTCs are a rapidly growing product area, averaging a 38% growth rate since 1997. Their production is dependent on substantial quantities of petroleum based thermoplastics, increasing their overall energy costs by over 230% when compared to traditional Engineered Wood Products (EWP). Utilizing bio-based thermoplastics for these materials can reduce our dependence on foreign petroleum. We have demonstrated that biopolymers (polyhydroxyalkanoates, PHA) can be successfully produced from wood pulping waste streams and that viable wood fiber reinforced thermoplastic composite products can be produced from these materials. The results show that microbial polyester (PHB in this study) can be extruded together with wastewater-derived cell mass and wood flour into deck products having performance properties comparable to existing commercial HDPE/WF composite products. This study has thus proven the underlying concept that the microbial polyesters produced from waste effluents can be used to make cost-effective and energy-efficient wood-plastic composites. The cost of purified microbial polyesters is about 5-20 times that of HDPE depending on the cost of crude oil, due to high purification (40%), carbon substrate (40%) and sterilized fermentation (20%) costs for the PHB. Hence, the ability to produce competitive and functional composites with unpurified PHA-biomass mixtures from waste carbon sources in unsterile systems—without cell debris removal—is a significant step forward in producing competitive value-added structural composites from forest products residuals using a biorefinery approach. As demonstrated in the energy and waste analysis for the project, significant energy savings and waste reductions can also be realized using this approach. We recommend that the next step for development of useful products using this technology is to scale the technology from the 700-L pilot reactor to a small-scale production facility, with dedicated operation staff and engineering controls. In addition, we recommend that a market study be conducted as well as further product development for construction products that will utilize the unique properties of this bio-based material.

David N. Thompson, Robert W. Emerick, Alfred B. England, James P. Flanders, Frank J. Loge, Katherine A. Wiedeman, Michael P. Wolcott

2010-03-31

292

Selection of materials for ventricular assist pump development and fabrication.  

PubMed

A study was undertaken to select 2 of the most promising bladder materials from a list of 8 carefully chosen polymers. The polymers chosen for testing included a wide spectrum of urethanes, as well as a polyester resin and a millable polyolefin rubber. The following materials were studied: Adiprene LW-500, Avcothane 51, Biomer, Hexsyn, Hytrel 4055, Mobay 240313, Pellethane 2103-80 AE, and Tecoflex HR. The selection process was based on a test matrix which was divided into segmented steps, each a logical sequel from its predecessor, and each of increasing technical complexity. Hydrolytic stability, flexure endurance, fabricability, tissue compatibility, hemocompatibility and chronic tissue compatibility were evaluated, forming the basis for the acceptance/rejection criteria. As a result of this search, 2 biomaterials were identified as most suitable for use in conventionally flocked bladders; Biomer and Tecoflex HR. Both Biomer and Tecoflex HR bladders have demonstrated impressive results in circulatory analog loop endurance tests, with Tecoflex bladders surpassing 50 million flexes to date, and Biomer bladders (the longest running bladders) exceeding 150 million flexes. Tests are continuing. PMID:910324

Szycher, M; Poirier, V; Keiser, J

1977-01-01

293

Fabrication of Bi-2223 high temperature superconducting magnet  

NASA Astrophysics Data System (ADS)

Bi-2223/Ag alloy multifilamentary tape, whose size was 0.21 mm in thickness, 3.14 mm in width and 400 m in length, was wound to 18 pancake coils to fabricate the high temperature superconducting magnet. Each single coil had an inner diameter of 50 mm and an outer diameter of 95 mm, and consumed about 20 m long superconducting tapes coated with 10 ?m thick polyester paint for insulation. The 18 pancake coils were stacked on a polyflon cylinder and the joints between each pancake coil were welded by tin solder and the copper current leads to the magnet as well. A couple of yokes had been added to the two sides of the magnet windings to decrease the radial magnetic flux density and therefore increase the Ic of the superconducting tapes. The maximum magnetic field reached 0.176 T while the Ic of the magnet was 8.16 A in the nitrogen liquid. The I- V curve, the B- I curve and the magnetic field space distribution of the magnet was tested.

Huang, H.; Wang, Y.; Zhang, P. P.; Han, Z. H.; Guo, S. Q.; Liu, M. L.; Liu, S. L.; Gu, C.

2003-04-01

294

A blanket design, apparatus, and fabrication techniques for the mass production of multilayer insulation blankets for the Superconducting Super Collider  

SciTech Connect

The multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) consists of full cryostat length assemblies of aluminized polyester film fabricated in the form of blankets and installed as blankets to the 4.5K cold mass and the 20K and 80K thermal radiation shields. Approximately 40,000 MLI blankets will be required in the 10,000 cryogenic devices comprising the SSC accelerator. Each blanket is nearly 17 meters long and 1.8 meters wide. This paper reports the blanket design, an apparatus, and the fabrication method used to mass produce pre-fabricated MLI blankets. Incorporated in the blanket design are techniques which automate quality control during installation of the MLI blankets in the SSC cryostat. The apparatus and blanket fabrication method insure consistency in the mass produced blankets by providing positive control of the dimensional parameters which contribute to the thermal performance of the MLI blanket. By virtue of the fabrication process, the MLI blankets have inherent features of dimensional stability three-dimensional uniformity, controlled layer density, layer-to-layer registration, interlayer cleanliness, and interlayer material to accommodate thermal contraction differences. 11 refs., 6 figs., 1 tab.

Gonczy, J.D.; Boroski, W.N.; Niemann, R.C.; Otavka, J.G.; Ruschman, M.K.; Schoo, C.J.

1989-09-01

295

Primary Implantation of Polyester-Covered Stent-Grafts for Transjugular Intrahepatic Portosystemic Stent Shunts (TIPSS): A Pilot Study  

SciTech Connect

Purpose: To investigate whether placement of a polyester-covered stent-graft increases the primary patency of transjugular intrahepatic portosystemic stent shunts (TIPSS). Methods: Between 1995 and 1997 Cragg Endopro or Passager MIBS stent-grafts were used for the creation of TIPSS in eight male patients, 35-59 years of age (mean 48 years). All patients suffered from recurrent variceal bleeding and/or refractory ascites due to liver cirrhosis. Seven stent-grafts were dilated to a diameter of 10 mm, one to 12 mm. Follow-up was performed with duplex ultrasound, clinical assessment, and angiography. Results: The technical success rate for creation of a TIPSS was 100%. The mean portosystemic pressure gradient decreased from 25 mmHg to 12 mmHg. In seven of eight patients TIPSS dysfunction occurred between 2 days and 3 years after stent-graft placement. In one patient the TIPSS is still primarily patent (224 days after creation). The secondary patency rates are 31 days to 3 years. Conclusion: The primary use of polyester-covered stent-grafts for TIPSS did not increase primary patency rates in our small series.

Cejna, Manfred; Thurnher, Siegfried [Department of Angiography and Interventional Radiology, University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Pidlich, Johann [Department of Gastroenterology and Hepatology, University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Kaserer, Klaus [Department of Clinical Pathology, University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Schoder, Maria; Lammer, Johannes [Department of Angiography and Interventional Radiology, University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)

1999-07-15

296

5-Fluorouracil-lipid conjugate: potential candidate for drug delivery through encapsulation in hydrophobic polyester-based nanoparticles.  

PubMed

The encapsulation of 5-fluorouracil (5-FU) in hydrophobic polymeric materials is made feasible by a lipid-based prodrug approach. A lipid-5-FU conjugate of 5-FU with palmitic acid was synthesized in two-step process. A synthesized dipalmitoyl derivative (5-FUDIPAL) was characterized using Fourier transform infrared spectroscopy and (1)H-nuclear magnetic resonance. The 5-FUDIPAL was encapsulated in polyester-based polymers by the double emulsion-solvent evaporation method. The nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy and dynamic light scattering. The thermal stability was assessed by differential scanning calorimetry data. In vitro release kinetics measurements of the drug from nanoparticles showed the controlled release pattern over a period of time. Cytotoxicity measurements by MTT assay confirmed that dipalmitoyl derivative in nano formulation successfully inhibited the cell growth. Thus the combined physical and biological evaluation of the different polyester-based nanoparticle containing the modified drug showed a facile approach to delivering 5-FU to the tumour site with enhanced efficacy. PMID:25110286

Ashwanikumar, N; Kumar, Nisha Asok; Nair, S Asha; Kumar, G S Vinod

2014-11-01

297

Understanding core conductor fabrics  

NASA Astrophysics Data System (ADS)

ESD Association standard test method ANSI/ESD STM2.1 - Garments (STM2.1), provides electrical resistance test procedures that are applicable for materials and garments that have surface conductive or surface dissipative properties. As has been reported in other papers over the past several years1 fabrics are now used in many industries for electrostatic control purposes that do not have surface conductive properties and therefore cannot be evaluated using the procedures in STM2.12. A study was conducted to compare surface conductive fabrics with samples of core conductor fibre based fabrics in order to determine differences and similarities with regards to various electrostatic properties. This work will be used to establish a new work item proposal within WG-2, Garments, in the ESD Association Standards Committee in the USA.

Swenson, D. E.

2011-06-01

298

Microfluidic channel fabrication method  

DOEpatents

A new channel structure for microfluidic systems and process for fabricating this structure. In contrast to the conventional practice of fabricating fluid channels as trenches or grooves in a substrate, fluid channels are fabricated as thin walled raised structures on a substrate. Microfluidic devices produced in accordance with the invention are a hybrid assembly generally consisting of three layers: 1) a substrate that can or cannot be an electrical insulator; 2) a middle layer, that is an electrically conducting material and preferably silicon, forms the channel walls whose height defines the channel height, joined to and extending from the substrate; and 3) a top layer, joined to the top of the channels, that forms a cover for the channels. The channels can be defined by photolithographic techniques and are produced by etching away the material around the channel walls.

Arnold, Don W. (Livermore, CA); Schoeniger, Joseph S. (Oakland, CA); Cardinale, Gregory F. (Oakland, CA)

2001-01-01

299

MOX Fabrication Isolation Considerations  

SciTech Connect

This document provides a technical position on the preferred level of isolation to fabricate demonstration quantities of mixed oxide transmutation fuels. The Advanced Fuel Cycle Initiative should design and construct automated glovebox fabrication lines for this purpose. This level of isolation adequately protects the health and safety of workers and the general public for all mixed oxide (and other transmutation fuel) manufacturing efforts while retaining flexibility, allowing parallel development and setup, and minimizing capital expense. The basis regulations, issues, and advantages/disadvantages of five potential forms of isolation are summarized here as justification for selection of the preferred technical position.

Eric L. Shaber; Bradley J Schrader

2005-08-01

300

Other Fabric Structures  

NASA Technical Reports Server (NTRS)

There are two kinds of fabric structures - tension, supported by cables and pylons, and those supported by air pressure within an enclosed fabric envelope. They are becoming increasingly popular with architects, engineers, etc., because of their aesthetic appeal, low cost and maintenance, energy efficiency and good space utilization. The Structo-Fab roof weighs only 1/30 as much as a conventional roof of that size. Giant fans are used to blow air into the envelope between the roof's outer membrane and its inner liner automatically maintaining the pressure differential necessary for roof rigidity.

1985-01-01

301

Fiber heart valve prosthesis: influence of the fabric construction parameters on the valve fatigue performances.  

PubMed

Transcatheter aortic valve replacement (TAVR) has become today a largely considered alternative technique to surgical valve replacement in patients who are not operable or patients with high risk for open chest surgery. However, the biological valve tissue used in the devices implanted clinically appears to be fragile material when folded for low diameter catheter insertion purpose and released in calcified environment with irregular geometry. Textile polyester material is characterized by outstanding folding and strength properties combined with proven biocompatibility. It could thereof be considered to replace biological valve leaflets in the TAVR procedure. The textile construction parameters must however be tuned to obtain a material compatible with the valve requested durability. In that context, one issue to be addressed is the friction effect that occurs between filaments and between yarns within a fabric under flexure loading. This phenomenon could be critical for the resistance of the material on the long term. The purpose of the present work is to assess the fatigue performances of textile valve prototypes made from different fabric constructions (monofilament, multifilament, calendered mutifilament) under accelerated cyclic loading. The goal is to identify, which construction is the best suited to long term fatigue stress. Results show that calendered multifilament and monofilament fabric constructions undergo strong ruptures already from 40 Mio cycles, while non calendered multifilament appears more durable. The rupture patterns observed point out that durability is directly related to the flexure stiffness level of the fibrous elements in the construction. PMID:25201184

Vaesken, Antoine; Heim, Frederic; Chakfe, Nabil

2014-12-01

302

Scheduling semiconductor wafer fabrication  

Microsoft Academic Search

The impact that scheduling can have on the performance of semi-conductor wafer fabrication facilities is assessed. The performance measure considered is the mean throughput time (sometimes called cycle time, turnaround time or manufacturing interval) for a lot of wafers. A variety of input control and sequencing rules are evaluated using a simulation model of a representative, but fictitious, semiconductor wafer

LAWRENCE M. WEIN

1988-01-01

303

MEMS Pressure Sensor Fabrication  

NSDL National Science Digital Library

This animated YouTube video, created by Southwest Center for Microsystems Education (SCME), illustrates the nine step process of micropressure sensor fabrication. In total, the video runs for 2:05. More information can be found on the SCME website, and corresponding materials for this animation can be downloaded from Educational Materials.

2014-07-31

304

Scaffolds for tissue fabrication  

Microsoft Academic Search

Tissue engineering is an interdisciplinary and multidisciplinary field. It has shown great promise in generating living alternatives for harvested tissues and organs for transplantation and reconstructive surgery. Materials and fabrication technologies are critically important for tissue engineering in designing temporary, artificial extracellular matrices (scaffolds), which support three-dimensional tissue formation. This review briefly introduces the concept of tissue engineering, and illustrates

Peter X Ma

2004-01-01

305

Animated Texels Fabrice Neyret  

E-print Network

Animated Texels Fabrice Neyret INRIA, Syntim Project B.P. 105, 78153 Le Chesnay Cedex, France of animating complex repetitive geometries, like the effects produced by the wind in a wheat field, or fur], hypertextures [7], volumetric textures [4, 5]. Animating these objects is also a very important point

Paris-Sud XI, Université de

306

Lithographic fabrication of nanoapertures  

DOEpatents

A new class of silicon-based lithographically defined nanoapertures and processes for their fabrication using conventional silicon microprocessing technology have been invented. The new ability to create and control such structures should significantly extend our ability to design and implement chemically selective devices and processes.

Fleming, James G. (Albuquerque, NM)

2003-01-01

307

Immobilization of organophosphohydrolase OpdA from Agrobacterium radiobacter by overproduction at the surface of polyester inclusions inside engineered Escherichia coli.  

PubMed

Organophosphorus pesticides (OP) are highly toxic and are widely used as insecticides. Bacterial organophosphohydrolases which hydrolyze a variety of OPs have been considered for the clean-up of polluted environments. This study describes the engineering of Escherichia coli towards the overproduction of the organophosphohydrolase (OpdA) from Agrobacterium radiobacter at the surface of polyester inclusions. The OpdA was N-terminally fused via a designed linker region to the C-terminus of polyester inclusion-forming enzyme PhaC of Ralstonia eutropha. The PhaC-L-OpdA fusion protein was overproduced by using the strong T7 promoter and when coexpressed with genes phaA (encoding ?-ketothiolase) and phaB (encoding acetoacetyl-CoA reductase) from R. eutropha this led to formation of polyester inclusions abundantly displaying OpdA. These OpdA beads showed organophosphohydrolase activity of 1,840 U/g wet polyester beads or 4,412 U/g protein. Steady state kinetics revealed that when compared with free OpdA the k(cat) (s(-1)) of 139 of immobilized OpdA was reduced by about 16.5-fold while the K(M) (M) of 2.5 × 10(-4) was increased by 1.6-fold. The immobilized OpdA showed increased temperature stability. Moreover, the stability of OpdA immobilized to polyester beads was assessed by incubating OpdA beads at 25°C for up to 11 days and no significant loss in enzyme activity was detected. The application performance of the OpdA beads with respect to hydrolysis of OPs in contaminated environments was demonstrated in wool scour spiked with fluorescent coumaphos. This study demonstrated a new strategy toward the efficient recombinant production of immobilized organophosphohydrolase, the OpdA, suitable for bioremediation applications. PMID:22170266

Blatchford, Paul A; Scott, Colin; French, Nigel; Rehm, Bernd H A

2012-05-01

308

Reactive processing of biodegradable polyesters with dicumyl peroxide: A structural, rheological and property study  

NASA Astrophysics Data System (ADS)

Studies were undertaken to gain an understanding as to the mechanistic, rheological, thermal, and mechanical property effects that can be expected by reactively extruding biodegradable polyesters with dicumyl peroxide (DCP). The two main polymers used were poly(epsilon-caprolactone), (PCL), and proprietary copolyester, Eastar 14766. The reactive extrusions were carried out at 160°C at various DCP levels. The percent branching and type of branching, (tetraor tri-functional), were determined by SEC and by the comparison of branched distributions to statistical models. It was found that PCL quantitatively formed tetra-functional branches while the Eastar 14766 formed a combination of tri- and tetra-functional branch points. The Eastar 14766 was also shown to be more reactive than the PCL, with half as much DCP being required to achieve equivalent amounts of branching. Thermal properties were studied by differential scanning calorimetry. In a multi-phase, upper critical solution temperature (UCST) system, such as Eastar 14766, the branches resulted in a compatiblization effect. This was shown as an increase in the glass transition temperature rising with the DCP level used in the reactive extrusion. The crystallization temperature decreased, and the heat of melting increased as the amount of branching/DCP level increased. The latter was attributed to the lower stereo regularity and/or the lower crystallization rate. The crystallization temperature increase is attributed to increased kinetics required, due to slower phase separation or increased viscosity. Branching/DCP level was shown to have a smaller effect on PCL, with the largest effect being an 11% relative decrease in heat of melting at the highest DCP level. Rheology studies showed that both Eastar 14766 and PCL displayed typical branching behavior with increases in melt elasticity and zero shear viscosity. An estimate of the plateau modulus revealed the entanglement molecular weight for Eastar 14766 to be approximately three times lower than that of PCL. This explained why Eastar 14766 had a larger enhancement in zero shear viscosity and elasticity than PCL. It was also noted, qualitatively, that branching in both materials produced a broadened elastic modulus curve. This was attributed to the difference in the molecular weight/relaxation time relationship between linear and branched materials. Tensile modulus and elongation studies showed PCL to be insensitive to branching. However, studies with Eastar 14766 showed tensile strength and elongation at break to be increased 30 and 10% respectively with branching. Tensile modulus on the other hand, remained relatively unchanged. These effects were attributed to phase changes due to increased compatibilization of the copolymer. A brief study of a 50/50 blend of Eastar 14766 and Poly(lactic acid) with and without DCP showed that the blend with DCP had a similar tensile strength. However, the ultimate elongation increased by 150% and the modulus decreased of 26%. This shows the possible utility of reactive blending with peroxides in order to achieve a higher degree of compatibilization in a blend.

Canale, Philip Louis

309

Automatic assessment of fabric smoothness  

Microsoft Academic Search

Due to its direct impact on the aesthetic appeal of apparels, a fabric's propensity to wrinkle is one of its most important characteristics. As such, access to a quantitative method of assessing fabric smoothness is of the utmost importance to the textile community. In this paper, we describe a vision system for measuring fabric smoothness in terms of its image

Chris Turner; H. Sari-Sarraf; Aijun Zhu; Eric Hequet; Sunho Lee

2002-01-01

310

Damage Evaluation of Unsaturated Polyester Resin Using Zero-Group Velocity Lamb Waves in Non-Contact Matter  

NASA Astrophysics Data System (ADS)

In this study we attempted to evaluate the degree of degradation of an unsaturated polyester resin when it was degraded by exposing it to hot water at 90°C, using the frequency of zero-group-velocity (ZGV) Lamb waves. The energy of ZGV Lamb waves does not propagate while the phase velocity remains finite. We generated ZGV Lamb waves with a Q-switched YAG laser and detected them with a focused air-coupled transducer at the same area of an irradiation point of the YAG laser in con-contact matter. A change in measured frequencies of ZGV Lamb waves decreased with increase of exposed period to hot water and are corresponding to the change in Young's modulus and thickness of the plate near the exposed surface

Cho, Hideo; Oka, Daichi; Matsuo, Takuma

311

Adhesion Properties of Catechol-Based Biodegradable Amino Acid-Based Poly(ester urea) Copolymers Inspired from Mussel Proteins.  

PubMed

Amino acid-based poly(ester urea) (PEU) copolymers functionalized with pendant catechol groups that address the need for strongly adhesive yet degradable biomaterials have been developed. Lap-shear tests with aluminum adherends demonstrated that these polymers have lap-shear adhesion strengths near 1 MPa. An increase in lap-shear adhesive strength to 2.4 MPa was achieved upon the addition of an oxidative cross-linker. The adhesive strength on porcine skin adherends was comparable with commercial fibrin glue. Interfacial energies of the polymeric materials were investigated via contact angle measurements and Johnson-Kendall-Roberts (JKR) technique. The JKR work of adhesion was consistent with contact angle measurements. The chemical and physical properties of PEUs can be controlled using different diols and amino acids, making the polymers candidates for the development of biological glues for use in clinical applications. PMID:25427310

Zhou, Jinjun; Defante, Adrian P; Lin, Fei; Xu, Ying; Yu, Jiayi; Gao, Yaohua; Childers, Erin; Dhinojwala, Ali; Becker, Matthew L

2015-01-12

312

Effects of Surface Treatments on Mechanical Properties and Water Resistance of Kenaf Fiber-Reinforced Unsaturated Polyester Composites  

SciTech Connect

Effects of surface treatments on the strength and water resistance of kenaf fiber-reinforced unsaturated polyester (UPE) composites were investigated. A new coupling agent that consists of 1,6-diisocyanato-hexane (DIH) and 2-hydroxylethyl acrylate (HEA) was investigated for surface treatments of kenaf fibers. The surface treatments were found to significantly enhance the tensile strength, modulus of rupture, modulus of elasticity, and water resistance of the resulting kenaf UPE composites. Fourier transform infrared spectroscopy (FTIR) confirmed that DIH-HEA was covalently bonded onto kenaf fibers. Scanning electron microscopy (SEM) images of the composites revealed that chemical treatment of kenaf fibers with a combination of DIH and HEA improved the interfacial adhesion between kenaf fibers and UPE resin in the DIHHEA-treated kenafUPE composites. The mechanisms by which the chemical treatment of kenaf fiber surfaces improved strength and water resistance of the resulting kenaf UPE composites were discussed.

Ren, Xiaofeng; Qui, Renhui; Fifield, Leonard S.; Simmons, Kevin L.; li, Kaichang

2012-05-17

313

Friction and wear behaviour of Kevlar fabrics  

Microsoft Academic Search

Experimental results of a number of tribological tests carried out on aramid woven fabrics are presented in this paper. Kevlar Ht, Kevlar 29 and Kevlar 49 aramid plain fabrics were employed in this work. The friction and wear phenomena of the fabrics were investigated, considering both fabric-fabric and metal-fabric interaction. From the experimental data, the evolution of parameters such as

M. A. Martínez; C. Navarro; R. Cortés; J. Rodríguez; N. Sanchez-Galvez

1993-01-01

314

PRSEUS Acoustic Panel Fabrication  

NASA Technical Reports Server (NTRS)

This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration with regards to acoustic response. A PRSEUS panel was designed and fabricated and provided to NASA-LaRC for acoustic response testing in the Structural Acoustics Loads and Transmission (SALT) facility). Preliminary assessments of the sound transmission characteristics of a PRSEUS panel subjected to a representative Hybrid Wing Body (HWB) operating environment were completed for the NASA Environmentally Responsible Aviation (ERA) Program.

Nicolette, Velicki; Yovanof, Nicolette P.; Baraja, Jaime; Mathur, Gopal; Thrash, Patrick; Pickell, Robert

2011-01-01

315

Mask fabrication process  

DOEpatents

A method for fabricating masks and reticles useful for projection lithography systems. An absorber layer is conventionally patterned using a pattern and etch process. Following the step of patterning, the entire surface of the remaining top patterning photoresist layer as well as that portion of an underlying protective photoresist layer where absorber material has been etched away is exposed to UV radiation. The UV-exposed regions of the protective photoresist layer and the top patterning photoresist layer are then removed by solution development, thereby eliminating the need for an oxygen plasma etch and strip and chances for damaging the surface of the substrate or coatings.

Cardinale, Gregory F. (Oakland, CA)

2000-01-01

316

Intraocular lens fabrication  

DOEpatents

This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

Salazar, M.A.; Foreman, L.R.

1997-07-08

317

Intraocular lens fabrication  

DOEpatents

This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

Salazar, Mike A. (Albuquerque, NM); Foreman, Larry R. (Los Alamos, NM)

1997-01-01

318

Fabrication of metal nanoshells  

NASA Technical Reports Server (NTRS)

Metal nanoshells are fabricated by admixing an aqueous solution of metal ions with an aqueous solution of apoferritin protein molecules, followed by admixing an aqueous solution containing an excess of an oxidizing agent for the metal ions. The apoferritin molecules serve as bio-templates for the formation of metal nanoshells, which form on and are bonded to the inside walls of the hollow cores of the individual apoferritin molecules. Control of the number of metal atoms which enter the hollow core of each individual apoferritin molecule provides a hollow metal nonparticle, or nanoshell, instead of a solid spherical metal nanoparticle.

Kim, Jae-Woo (Inventor); Choi, Sang H. (Inventor); Lillehei, Peter T. (Inventor); Chu, Sang-Hyon (Inventor); Park, Yeonjoon (Inventor); King, Glen C. (Inventor); Elliott, Jr., James R. (Inventor)

2012-01-01

319

Electrochemical fabrication of capacitors  

DOEpatents

A film of nickel oxide is anodically deposited on a graphite sheet held in osition on an electrochemical cell during application of a positive electrode voltage to the graphite sheet while exposed to an electrolytic nickel oxide solution within a volumetrically variable chamber of the cell. An angularly orientated x-ray beam is admitted into the cell for transmission through the deposited nickel oxide film in order to obtain structural information while the film is subject to electrochemical and in-situ x-ray spectroscopy from which optimum film thickness, may be determined by comparative analysis for capacitor fabrication purposes.

Mansour, Azzam N. (Fairfax Sta., VA); Melendres, Carlos A. (Lemont, IL)

1999-01-01

320

Alternating copolymerization of propylene oxide with biorenewable terpene-based cyclic anhydrides: a sustainable route to aliphatic polyesters with high glass transition temperatures.  

PubMed

The alternating copolymerization of propylene oxide with terpene-based cyclic anhydrides catalyzed by chromium, cobalt, and aluminum salen complexes is reported. The use of the Diels-Alder adduct of ?-terpinene and maleic anhydride as the cyclic anhydride comonomer results in amorphous polyesters that exhibit glass transition temperatures (Tg ) of up to 109?°C. The polymerization conditions and choice of catalyst have a dramatic impact on the molecular weight distribution, the relative stereochemistry of the diester units along the polymer chain, and ultimately the Tg of the resulting polymer. The aluminum salen complex exhibits exceptional selectivity for copolymerization without transesterification or epimerization side reactions. The resulting polyesters are highly alternating and have high molecular weights and narrow polydispersities. PMID:25611489

Van Zee, Nathan J; Coates, Geoffrey W

2015-02-23

321

Facile Functionalization of Polyesters through Thiol-yne Chemistry for the Design of Degradable, Cell–Penetrating and Gene Delivery Dual–Functional Agents  

PubMed Central

Synthesis of polyesters bearing pendant amine groups with controlled molecular weights and narrow molecular weight distributions was achieved through ring-opening polymerization of 5-(4-(prop-2-yn-1-yloxy)benzyl)-1,3-dioxolane-2,4-dione, an O-carboxyanhydride derived from tyrosine, followed by thiol-yne “click” photochemistry with 2-aminoethanethiol hydrochloride. This class of biodegradable polymers displayed excellent cell penetration and gene delivery properties with low toxicities. PMID:23098261

Zhang, Zhonghai; Yin, Lichen; Xu, Yunxiang; Tong, Rong; Lu, Yanbing; Ren, Jie; Cheng, Jianjun

2013-01-01

322

New Skin Test for Detection of Bovine Tuberculosis on the Basis of Antigen-Displaying Polyester Inclusions Produced by Recombinant Escherichia coli  

PubMed Central

The tuberculin skin test for diagnosing tuberculosis (TB) in cattle lacks specificity if animals are sensitized to environmental mycobacteria, as some antigens in purified protein derivative (PPD) prepared from Mycobacterium bovis are present in nonpathogenic mycobacteria. Three immunodominant TB antigens, ESAT6, CFP10, and Rv3615c, are present in members of the pathogenic Mycobacterium tuberculosis complex but absent from the majority of environmental mycobacteria. These TB antigens have the potential to enhance skin test specificity. To increase their immunogenicity, these antigens were displayed on polyester beads by translationally fusing them to a polyhydroxyalkanoate (PHA) synthase which mediated formation of antigen-displaying inclusions in recombinant Escherichia coli. The most common form of these inclusions is poly(3-hydroxybutyric acid) (PHB). The respective fusion proteins displayed on these PHB inclusions (beads) were identified using tryptic peptide fingerprinting analysis in combination with matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). The surface exposure and accessibility of antigens were assessed by enzyme-linked immunosorbent assay (ELISA). Polyester beads displaying all three TB antigens showed greater reactivity with TB antigen-specific antibody than did beads displaying only one TB antigen. This was neither due to cross-reactivity of antibodies with the other two antigens nor due to differences in protein expression levels between beads displaying single or three TB antigens. The triple-antigen-displaying polyester beads were used for skin testing of cattle and detected all cattle experimentally infected with M. bovis with no false-positive reactions observed in those sensitized to environmental mycobacteria. The results suggested applicability of TB antigen-displaying polyester inclusions as diagnostic reagents for distinguishing TB-infected from noninfected animals. PMID:24532066

Chen, Shuxiong; Parlane, Natalie A.; Lee, Jason; Wedlock, D. Neil; Buddle, Bryce M.

2014-01-01

323

Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations  

Microsoft Academic Search

A carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin (CuP-Poly) is proposed for voltammetric determination of l -ascorbic acid in pharmaceutical formulations. The modified electrode allows the detection of l -ascorbic acid at lower anodic potentials than observed at unmodified electrodes. Several parameters that can influence the voltammetric response of the proposed electrode such as carbon

Marcos F. S. Teixeira; Luiz A. Ramos; Orlando Fatibello-Filho; Éder T. G. Cavalheiro

2003-01-01

324

Ceramic fabrication R D  

SciTech Connect

This project is separated into three tasks. The first task is a design and modeling effort to be carried out by MSE, Inc. The purpose of this task is to develop and analyze designs for various cohesive ceramic fabrication (CCF) components. This quarter, the advanced molybdenum disicilide MHD electrode design was essentially completed. Final refinements will be made after molybdenum disilicide processing results are available and the final layer compositions are established. Work involving whisker incorporation was initiated on the high stress component. It is unlikely that whiskers will become low cost, so particulate reinforcement will be pursued. Modeling work will resume once a suitable aluminum oxide/silicon carbide composition is selected that can be fired to acceptable densities by pressureless sintering. Task 2, subcontracted to Applied Technology Laboratories (ATL), is principally directed at establishing a property data base for monolithic and laminated alumina fabricated using the CCF process. This quarter, ATL demonstrated that the CCF process does not compromise the flexure strength of alumina. Task 3, subcontracted to Ceramics Binder Systems, Inc., focused on CCF silicon carbide particulate reinforced alumina and on the development of processing procedures for nonoxide molybdenum disilicide. Preliminary results indicate that achieving high densities in silicon carbide particulate reinforced aluminum oxide will be difficult. Molybdenum disilicide results are encouraging, and it is clear that the CCF process will work with this nonoxide material. 3 refs., 18 figs., 4 tabs.

Not Available

1990-01-01

325

NCSX Vacuum Vessel Fabrication  

SciTech Connect

The National Compact Stellarator Experiment (NCSX) is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in conjunction with the Oak Ridge National Laboratory (ORNL). The goal of this experiment is to develop a device which has the steady state properties of a traditional stellarator along with the high performance characteristics of a tokamak. A key element of this device is its highly shaped Inconel 625 vacuum vessel. This paper describes the manufacturing of the vessel. The vessel is being fabricated by Major Tool and Machine, Inc. (MTM) in three identical 120º vessel segments, corresponding to the three NCSX field periods, in order to accommodate assembly of the device. The port extensions are welded on, leak checked, cut off within 1" of the vessel surface at MTM and then reattached at PPPL, to accommodate assembly of the close-fitting modular coils that surround the vessel. The 120º vessel segments are formed by welding two 60º segments together. Each 60º segment is fabricated by welding ten press-formed panels together over a collapsible welding fixture which is needed to precisely position the panels. The vessel is joined at assembly by welding via custom machined 8" (20.3 cm) wide spacer "spool pieces." The vessel must have a total leak rate less than 5 X 10-6 t-l/s, magnetic permeability less than 1.02?, and its contours must be within 0.188" (4.76 mm). It is scheduled for completion in January 2006.

Viola, M. E.; Brown, T.; Heitzenroeder, P.; Malinowski, F.; Reiersen, W.; Sutton, L.; Goranson, P.; Nelson, B.; Cole, M.; Manuel, M.; McCorkle, D.

2005-10-07

326

Characterization of complex phthalic acid/propylene glycol based polyesters by the combination of 2D chromatography and MALDI-TOF mass spectrometry.  

PubMed

The combination of gradient HPLC, 2D chromatography, and MALDI-TOF MS facilitated the analysis of the various distributions of phthalic acid/propylene glycol-based model polyesters. Investigations of kinetic samples taken at various reaction times highlighted the subsequent differences at various stages of the polyesterification reaction in terms of molecular weight, chemical composition, and endgroups. Normal-phase gradient-HPLC analysis successfully enabled an oligomeric separation of the respective samples. Peak-splitting behavior in early eluting peaks suggested that the separation was affected by a combination of factors and not solely based on chemical composition, functionality type or degree of polycondensation. Two-dimensional chromatography provided the link between chemical composition and molecular weight distribution, confirming that the first dimension gradient HPLC separation was based on chemical composition with increasing degree of oligomerization in the second dimension. The off-line coupling of LAC with MALDI-TOF MS provided structural details in combination with improved molecular weight determination of the more homogeneous LC fractions. The study indicated that all aspects related to the model saturated anhydride system should be considered in the case of copolyester synthesis to produce industrial type polyester resins. It was shown that the present multidimensional approach provided most comprehensive structural information on the polyester system. PMID:24848117

Pretorius, Nadine O; Rhode, Karsten; Simpson, Jaylin M; Pasch, Harald

2015-01-01

327

Analysis of complex phthalic acid based polyesters by the combination of size exclusion chromatography and matrix-assisted laser desorption/ionization mass spectrometry.  

PubMed

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used in conjunction with size exclusion chromatography (SEC) to investigate a model polyester system based on phthalic anhydride-1,2-propylene glycol. The polyesters were synthesized with a 30% molar excess of glycol, with kinetic samples being removed during different intervals of the polyesterification reaction. SEC was used to track the course of the reaction by determining the molecular weight and molecular weight distributions before subsequent off-line coupling with MALDI-TOF MS as a selective detection method to determine the chemical composition, identify the functionality type distributions as well as assist in assigning structural conformations. Mass spectrometry analysis proved to be a highly effective tool to facilitate the identification of the narrowly dispersed fractions obtained from the chromatographic separations as well as serve as a core method to investigate the heterogeneous nature of the bulk kinetic samples. Through the hyphenation of these sophisticated polymer characterization techniques, information on the molecular heterogeneity of the model polyesters, showing a complex variety of possible distributions, was obtained. PMID:24370096

Pretorius, Nadine O; Rode, Karsten; Simpson, Jaylin M; Pasch, Harald

2014-01-15

328

AFIP-6 Fabrication Summary Report  

SciTech Connect

The AFIP-6 (ATR Full-size plate In center flux trap Position) experiment was designed to evaluate the performance of monolithic fuels at a scale prototypic of research reactor fuel plates. Two qualified fueled plates were fabricated for the AFIP-6 experiment; to be irradiated in the INL Advanced Test Reactor (ATR). This report provides details of the fuel fabrication efforts, including material selection, fabrication processes, and fuel plate qualification.

Glenn A. Moore; M. Craig Marshall

2011-09-01

329

AFIP-4 Fabrication Summary Report  

SciTech Connect

The AFIP-4 (ATR Full –size-plate In center flux trap Position) experiment was designed to evaluate the performance of monolithic fuels at a scale prototypic of research reactor fuel plates. Twelve qualified fueled plates were fabricated for the AFIP-4 experiment; to be irradiated in the INL Advanced Test Reactor (ATR). This report provides details of the fuel fabrication efforts; including material selection, fabrication processes, and fuel plate qualification.

Glenn A. Moore

2010-02-01

330

AFIP-2 Fabrication Summary Report  

SciTech Connect

The Advanced Test Reactor (ATR) Full-size Plate In Center Flux Trap Position (AFIP)-2 experiment was designed to evaluate the performance of monolithic fuels at a scale prototypic of research reactor fuel plates. Two qualified fueled plates were fabricated for the AFIP 2 experiment to be irradiated in the Idaho National Laboratory ATR. This report provides details of the fuel fabrication efforts, including material selection, fabrication processes, and fuel plate qualification.

Glenn Moore

2010-02-01

331

Fabricating a hybrid imaging device  

NASA Technical Reports Server (NTRS)

A hybrid detector or imager includes two substrates fabricated under incompatible processes. An array of detectors, such as charged-coupled devices, are formed on the first substrate using a CCD fabrication process, such as a buried channel or peristaltic process. One or more charge-converting amplifiers are formed on a second substrate using a CMOS fabrication process. The two substrates are then bonded together to form a hybrid detector.

Wadsworth, Mark (Inventor); Atlas, Gene (Inventor)

2003-01-01

332

Cutinase treatment of cotton fabrics  

Microsoft Academic Search

Our study proposes an enzymatic scouring method for cotton fabrics using the enzyme cutinase. We established cutinase treatment\\u000a conditions for cotton fabrics from their relative activity at different pH levels, temperatures, enzyme concentrations, and\\u000a treatment times. Weight loss, moisture regain, K\\/S value, tensile strength, and SEM micrographs of cotton fabrics were analyzed. We determined the optimum cutinase treatment\\u000a conditions to

So Hee Lee; Wha Soon Song; Hye Rim Kim

2009-01-01

333

Multifunctional graphene woven fabrics  

PubMed Central

Tailoring and assembling graphene into functional macrostructures with well-defined configuration are key for many promising applications. We report on a graphene-based woven fabric (GWF) prepared by interlacing two sets of graphene micron-ribbons where the ribbons pass each other essentially at right angles. By using a woven copper mesh as the template, the GWF grown from chemical vapour deposition retains the network configuration of the copper mesh. Embedded into polymer matrices, it has significant flexibility and strength gains compared with CVD grown graphene films. The GWFs display both good dimensional stability in both the warp and the weft directions and the combination of film transparency and conductivity could be optimized by tuning the ribbon packing density. The GWF creates a platform to integrate a large variety of applications, e.g., composites, strain sensors and solar cells, by taking advantages of the special structure and properties of graphene. PMID:22563524

Li, Xiao; Sun, Pengzhan; Fan, Lili; Zhu, Miao; Wang, Kunlin; Zhong, Minlin; Wei, Jinquan; Wu, Dehai; Cheng, Yao; Zhu, Hongwei

2012-01-01

334

Fabricating scaffolds by microfluidics  

PubMed Central

In this paper, we demonstrate for the first time the technique to using microfluidics to fabricate tissue engineering scaffolds with uniform pore sizes. We investigate both the bubble generation of the microfluidic device and the application of foam as a tissue engineering scaffold. Our microfluidic device consists of two concentric tapered channels, which are made by micropipettes. Nitrogen gas and aqueous alginate solution with Pluronic® F127 surfactant are pumped through the inner and the outer channels, respectively. We observe rich dynamic patterns of bubbles encapsulated in the liquid droplets. The size of the bubble depends linearly on the gas pressure and inversely on the liquid flow rate. In addition, monodisperse bubbles self-assemble into crystalline structures. The liquid crystalline foams are further processed into open-cell solid foams. The novel foam gel was used as a scaffold to culture chondrocytes. PMID:19693338

Chung, Kuo-yuan; Mishra, Narayan Chandra; Wang, Chen-chi; Lin, Feng-hui; Lin, Keng-hui

2009-01-01

335

Fabrication of a model continuously graded co-electrospun mesh for regeneration of the ligament-bone interface.  

PubMed

Current scaffolds for the regeneration of anterior cruciate ligament injuries are unable to capture intricate mechanical and chemical gradients present in the natural ligament-bone interface. As a result, stress concentrations can develop at the scaffold-bone interface, leading to poor osseointegration. Hence, scaffolds that possess appropriate mechano-chemical gradients would help establish normal loading properties at the interface, while promoting scaffold integration with bone. With the long-term goal of investigating regeneration of the ligament-bone interface, this feasibility study aimed to fabricate a continuously graded mesh. Specifically, graded meshes were fabricated by co-electrospinning nanohydroxyapatite/polycaprolactone (nHAP-PCL) and poly(ester urethane) urea elastomer solutions from offset spinnerets. Next, mineral crystallites were selectively deposited on the nHAP-PCL fibers by treatment with a 5× simulated body fluid (5× SBF). X-ray diffraction and energy-dispersive spectroscopy indicated calcium-deficient hydroxyapatite-like mineral crystallites with an average Ca/P ratio of 1.48. Tensile testing demonstrated the presence of a mechanical gradient, which became more pronounced upon treatment with 5× SBF. Finally, biocompatibility of the graded meshes was verified using an MC3T3-E1 osteoprogenitor cell line. The study demonstrates that graded meshes, for potential application in interfacial tissue engineering, can be fabricated by co-electrospinning. PMID:21791254

Samavedi, Satyavrata; Olsen Horton, C; Guelcher, Scott A; Goldstein, Aaron S; Whittington, Abby R

2011-12-01

336

A comparison of the use of vacuum metal deposition versus cyanoacrylate fuming for visualisation of fingermarks and grab impressions on fabrics.  

PubMed

Both vacuum metal deposition (VMD) and cyanoacrylate fuming (CAF) are techniques used to visualise latent fingermarks on smooth non-porous surfaces such as plastic and glass. VMD was initially investigated in the 1970s as to its effectiveness for visualising prints on fabrics, but was abandoned when radioactive sulphur dioxide was found to be more effective. However, interest in VMD was resurrected in the 1990s when CAF was also used routinely. We now report on studies to determine whether VMD or CAF is the more effective technique for the detection of marks on fabrics. Four different fabrics, nylon, polyester, polycotton and cotton, were utilised during this study, along with 15 donors who ranged in their age and ability to leave fingermarks, from good to medium to poor, thus reflecting the general population. Once samples were collected they were kept for a determined time (1, 2, 3, 4, 5, 6, 7, 14, 21 or 28 days) and then treated using either the gold and zinc metal VMD process or standard cyanoacrylate fuming. The smoother fabrics, such as nylon, consistently produced greater ridge detail whereas duller fabrics, like cotton tended only to show empty prints and impressions of where the fabric had been touched, rather than any ridge details. The majority of fabrics did however allow the development of touch marks that could be targeted for DNA taping which potentially could lead to a DNA profile. Of the two techniques VMD was around 5 times more effective than CAF, producing a greater amount of ridge detail, palmar flexion creases and target areas on more samples and fabrics. PMID:24630323

Fraser, Joanna; Deacon, Paul; Bleay, Stephen; Bremner, David H

2014-03-01

337

Process for fabrication of cermets  

DOEpatents

Cermet comprising ceramic and metal components and a molten metal infiltration method and process for fabrication thereof. The light weight cermets having improved porosity, strength, durability, toughness, elasticity fabricated from presintered ceramic powder infiltrated with a molten metal or metal alloy. Alumina titanium cermets biocompatible with the human body suitable for bone and joint replacements.

Landingham, Richard L. (Livermore, CA)

2011-02-01

338

CW RFQ fabrication and engineering  

SciTech Connect

The design and fabrication of a four-vane RFQ to deliver a 100 mA CW proton beam at 6.7 MeV is described. This linac is an Oxygen-Free Electrolytic (OFE) copper structure 8 m in length and was fabricated using hydrogen furnace brazing as the joining technology.

Schrage, D.; Young, L.; Roybal, P. [and others

1998-12-31

339

Influence of cow bone particle size distribution on the mechanical properties of cow bone-reinforced polyester composites.  

PubMed

This work was carried out to investigate the influence of cow bone particle size distribution on the mechanical properties of polyester matrix composites in order to consider the suitability of the materials as biomaterials. Cow bone was procured from an abattoir, washed with water, and sun-dried for 4 weeks after which it was crushed with a sledge hammer and was further pulverized with laboratory ball mill. Sieve size analysis was carried out on the pulverized bone where it was sieved into three different sizes of 75, 106, and 300??m sieve sizes. Composite materials were developed by casting them into tensile and flexural tests moulds using predetermined proportions of 2, 4, 6, and 8%. The samples after curing were striped from the moulds and were allowed to be further cured at room temperature for 3 weeks before tensile and flexural tests were performed on them. Both tensile and flexural strength were highly enhanced by 8 wt% from 75??m while toughness was highly enhanced by 6 and 8?wt% from 300??m. This shows that fine particles lead to improved strength while coarse particles lead to improved toughness. The results show that these materials are structurally compatible and are being developed from animal fibre based particle; it is expected to also aid the compatibility with the surface conditions as biomaterials. PMID:24324892

Oladele, Isiaka Oluwole; Adewole, Temitope Akinyemi

2013-01-01

340

Surface Characterization of Asymmetric Bi-Soft Segment Poly(ester urethane urea) Membranes for Blood-Oxygenation Medical Devices  

PubMed Central

Asymmetric bi-soft segment poly(ester urethane urea) (PEUU) membranes containing polycaprolactone (PCL) as a second soft segment are synthesized with PCL-diol ranging from 0% to 15% (w/w). Bulk and surface characteristics of the PEUU membranes were investigated by scanning electron microscopy (SEM), static water contact angles, and surface streaming potentials and were correlated to hemocompatibility properties, namely, hemolysis and thrombosis degrees. SEM analysis reveals PEUU membranes with asymmetric cross-sections and top dense surfaces with distinct morphologies. The increase in PCL-diol content yields PEUU membranes with blood-contacting surfaces that are smoother, more hydrophilic, and with higher maximum zeta potentials. The results obtained in this work give no evidence of a correlation between hydrophilicity/zeta potentials and the hemolysis/thrombosis degree of blood-contacting surfaces of the PEUU membranes. In contrast, other hemocompatibility aspects reveal that the more hydrophilic membranes are associated with lower platelet deposition and inhibition of extreme states of platelet activation. PMID:22164163

Faria, Mónica; Geraldes, Vítor; de Pinho, Maria Norberta

2012-01-01

341

Thermal characterization of composites made up of magnetically aligned carbonyl iron particles in a polyester resin matrix  

NASA Astrophysics Data System (ADS)

The thermal characterization of composites made up by magnetically aligned carbonyl iron micro-sized particles embedded in a polyester resin matrix is performed using photothermal radiometry technique. The measured experimental data show that the thermal conductivity and thermal diffusivity of the composite, in the direction of the applied magnetic field, increase with the concentration of the particles and are enhanced with respect to their corresponding values for a random distribution of the particles. This thermal enhancement has a maximum at a concentration of particles of 10% and is very low at small and high iron volume fractions, such that for particles concentrations of about 40%, the composite thermal conductivity reduces to its values for random particles. This behavior indicates that for high volume fractions, the effect of the microparticles concentration plays a dominant role over the effect of their alignment. It is shown that the thermal conductivity of the composite can be modeled in terms of the Nielsen model, under an appropriate parameterization of the form factor of the particles. The results of this work could be highly useful for improving the thermal performance of mechanical and electronic devices involving composite materials.

Medina-Esquivel, R. A.; Zambrano-Arjona, M. A.; Mendez-Gamboa, J. A.; Yanez-Limon, J. M.; Ordonez-Miranda, J.; Alvarado-Gil, J. J.

2012-03-01

342

Influence of Cow Bone Particle Size Distribution on the Mechanical Properties of Cow Bone-Reinforced Polyester Composites  

PubMed Central

This work was carried out to investigate the influence of cow bone particle size distribution on the mechanical properties of polyester matrix composites in order to consider the suitability of the materials as biomaterials. Cow bone was procured from an abattoir, washed with water, and sun-dried for 4 weeks after which it was crushed with a sledge hammer and was further pulverized with laboratory ball mill. Sieve size analysis was carried out on the pulverized bone where it was sieved into three different sizes of 75, 106, and 300??m sieve sizes. Composite materials were developed by casting them into tensile and flexural tests moulds using predetermined proportions of 2, 4, 6, and 8%. The samples after curing were striped from the moulds and were allowed to be further cured at room temperature for 3 weeks before tensile and flexural tests were performed on them. Both tensile and flexural strength were highly enhanced by 8 wt% from 75??m while toughness was highly enhanced by 6 and 8?wt% from 300??m. This shows that fine particles lead to improved strength while coarse particles lead to improved toughness. The results show that these materials are structurally compatible and are being developed from animal fibre based particle; it is expected to also aid the compatibility with the surface conditions as biomaterials. PMID:24324892

Oladele, Isiaka Oluwole; Adewole, Temitope Akinyemi

2013-01-01

343

Thermal performance measurements of a 100 percent polyester MLI (multilayer insulation) system for the Superconducting Super Collider  

SciTech Connect

Thermal performance measurements of a 100 percent polyester multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) were conducted in a Heat Leak Test Facility (HLTF) under three experimental test arrangements. Each experiment measured the thermal performance of a 32-layer MLI blanket instrumented with twenty foil sensors to measure interstitial layer temperatures. Heat leak values and sensor temperatures were monitored during transient and steady state conditions under both design and degraded insulating vacuums. Heat leak values were measured using a heatmeter. MLI interstitial layer temperatures were measured using Cryogenic Linear Temperature Sensors (CLTS). Platinum resistors monitored system temperatures. High vacuum was measured using ion gauges; degraded vacuum employed thermocouple gauges. A four-wire system monitored instrumentation sensors and calibration heaters. An on-line computerized data acquisition system recorded and processes data. This paper reports on the instrumentation and experimental preparation used in carrying out these measurements. In complement with this paper is an associate paper bearing the same title head, but with the title extension Part 2: Laboratory results (300K--80K). 13 refs., 7 figs.

Boroski, W.N.; Gonczy, J.D.; Niemann, R.C.

1989-09-01

344

Determining the viscoelastic properties obtained by depth sensing microindentation of epoxy and polyester thermosets using a new phenomenological method  

NASA Astrophysics Data System (ADS)

Epoxy and polyester thermosets are currently used as the polymer matrix material for many fiber-reinforced composite systems. The viscoelastic properties of these materials were investigated in this study by use of depth sensing microindentation. The microindentation tests performed had the load being applied at a rapid loading rate to a maximum load. This maximum load was held constant while the stylus continued to sink. It was then unloaded at a nominal rate. A new phenomenological model developed by Schwarzer in 2014 was used in this work to determine the viscoelastic properties. Two approaches or methods were used. The first method involved determining the three parameters by using hold time data combined with unloading data (this method is referred to in this work as ‘hold time method’). The second method used only the unloading data (this method is referred to in this work as ‘unloading method’). It was shown that the properties determined by the two methods are not the same but are dependent upon the strain rate behavior during the indentation test. Low load scratch tests were also performed. It was seen that as the sliding speed increased the depth of penetration decreased resulting in the coefficient of friction also decreasing. An understanding of the viscoelastic properties at the surface and how they affect friction are important in studying wear of these materials.

Kohl, James G.; Schwarzer, Norbert; Ngo, Truc T.; Favaro, Gregory; Rengnet, Eric; Bierwisch, Nick

2015-01-01

345

Preparation and characterization of tablet formulation based on solid dispersion of glimepiride and poly(ester amide) hyperbranched polymer.  

PubMed

The feasibility of incorporating a solid dispersion containing poorly soluble antidiabetic drug glimepiride and poly(ester amide) hyperbranched polymer into a tablet using a direct-compression tabletting technique was investigated. Tablet cores were additionally coated with hydroxypropyl methylcellulose phthalate in order to protect the extremely hygroscopic solid dispersion from atmospheric moisture. Preliminary stability studies show that glimepiride, which is in amorphous form within solid dispersion, is chemically stable, even if tablets are exposed to elevated temperature and/or moisture. In-vitro dissolution studies show some impact of storage conditions on the tablet cores disintegration time and, consequently, drug release rate. Glimepiride solubility also deteriorates somewhat, most probably due to its partial recrystallization. Storage conditions much less affect the physical stability of coated tablets, which was ascribed to reduced tablet hygroscopicity due to the presence of protecting coating. The hyperbranched polymers are rather new and complex macromolecules. Therefore, we addressed also the biocompatibility of hyperbranched polymer, i.e., its impact on haemolysis of the red blood cells. The concentration required for the haemolytic effect on the red blood cells is around 100-times higher than its expected gastrointestinal luminal concentration, which makes the occurrence of hyperbranched polymer mediated cytotoxicity very unlikely. PMID:21812524

Reven, Sebastjan; Homar, Miha; Peternel, Luka; Kristl, Julijana; Žagar, Ema

2013-01-01

346

Polyester-idarubicin nanoparticles and a polymer-photosensitizer complex as potential drug formulations for cell-mediated drug delivery.  

PubMed

Cell-mediated transport of therapeutics has emerged as promising alternative to classical drug delivery approaches. To preserve viability and functions of carrier cells, encapsulation of active drugs in protective nanoparticles or the use of inducible therapeutics has been proposed. Here, we compared the effects of novel polymeric formulations of an active and a stimulus-sensitive anti-cancer drug on human T lymphocytes to identify suitable drug preparations for cell-mediated drug delivery. For the first approach, the chemotherapeutic agent idarubicin (IDA) was encapsulated in poly(lactic-co-glycolic-acid) (PLGA) and newly developed maleate-polyester (MPE) nanoparticles. PLGA- and MPE-encapsulated IDA was efficiently internalized by ex vivo activated human T lymphocytes; however, both encapsulations could not prevent premature T cell death resulting from IDA-uptake. In contrast, loading with a poly(styrene sulfonate) (PSS)-complex of the light-sensitive pharmaceutical 5,10,15,20-tetrakis(meso-hydroxyphenyl)porphyrin (mTHPP) did not affect T cell viability if upon loading the cells were kept in the dark. The photosensitizer was transferred from loaded T lymphocytes to co-cultivated carcinoma cells, and induced cancer cell death if co-cultures were exposed to light. Inducible drugs, such as photosensitizers, thus, may help to overcome the limitations of encapsulated active drugs and open up new perspectives for the use of cells as drug transporters in cancer therapy. PMID:25089507

Blaudszun, André-R; Lian, Qiong; Schnabel, Melanie; Loretz, Brigitta; Steinfeld, Ute; Lee, Hyeck-H; Wenz, Gerhard; Lehr, Claus-M; Schneider, Marc; Philippi, Anja

2014-10-20

347

Biodegradable poly(ester urethane)urea elastomers with variable amino content for subsequent functionalization with phosphorylcholine.  

PubMed

While surface modification is well suited for imparting biomaterials with specific functionality for favorable cell interactions, the modification of degradable polymers would be expected to provide only temporary benefit. Bulk modification by incorporating pendant reactive groups for subsequent functionalization of biodegradable polymers would provide a more enduring approach. Towards this end, a series of biodegradable poly(ester urethane)urea elastomers with variable amino content (PEUU-NH2 polymers) were developed. Carboxylated phosphorycholine was synthesized and conjugated to the PEUU-NH2 polymers for subsequent bulk functionalization to generate PEUU-PC polymers. Synthesis was verified by proton nuclear magnetic resonance, X-ray photoelectron spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy. The impact of amine incorporation and phosphorylcholine conjugation was shown on mechanical, thermal and degradation properties. Water absorption increased with increasing amine content, and further with PC conjugation. In wet conditions, tensile strength and initial modulus generally decreased with increasing hydrophilicity, but remained in the range of 5-30 MPa and 10-20 MPa, respectively. PC conjugation was associated with significantly reduced platelet adhesion in blood contact testing and the inhibition of rat vascular smooth muscle cell proliferation. These biodegradable PEUU-PC elastomers offer attractive properties for applications as non-thrombogenic, biodegradable coatings and for blood-contacting scaffold applications. Further, the PEUU-NH2 base polymers offer the potential to have multiple types of biofunctional groups conjugated onto the backbone to address a variety of design objectives. PMID:25132273

Fang, Jun; Ye, Sang-Ho; Shankarraman, Venkat; Huang, Yixian; Mo, Xiumei; Wagner, William R

2014-11-01

348

Synthesis of poly(ethylene furandicarboxylate) polyester using monomers derived from renewable resources: thermal behavior comparison with PET and PEN.  

PubMed

Poly(ethylene-2,5-furandicarboxylate) (PEF) is a new alipharomatic polyester that can be prepared from monomers derived from renewable resources like furfural and hydroxymethylfurfural. For this reason it has gained high interest recently. In the present work it was synthesized from the dimethylester of 2,5-furandicarboxylic acid and ethylene glycol by applying the two-stage melt polycondensation method. The thermal behavior of PEF was studied in comparison to its terephthalate and naphthalate homologues poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN), which were also synthesized following the same procedure. The equilibrium melting point of PEF was found to be 265 °C while the heat of fusion for the pure crystalline PEF was estimated to be about 137 J g(-1). The crystallization kinetics was analyzed using various models. PET showed faster crystallization rates than PEN and this in turn showed faster crystallization than PEF, under both isothermal and non-isothermal conditions. The spherulitic morphology of PEF during isothermal crystallization was investigated by polarized light microscopy (PLM). A large nucleation density and a small spherulite size were observed for PEF even at low supercoolings, in contrast to PET or PEN. Thermogravimetric analysis indicated that PEF is thermally stable up to 325 °C and the temperature for the maximum degradation rate was 438 °C. These values were a little lower than those for PET or PEN. PMID:24647534

Papageorgiou, George Z; Tsanaktsis, Vasilios; Bikiaris, Dimitrios N

2014-05-01

349

Kinetics and isotherm analysis of Tropaeoline 000 adsorption onto unsaturated polyester resin (UPR): a non-carbon adsorbent.  

PubMed

The presence of dyes in water is undesirable due to the toxicological impact of their entrance into the food chain. Owing to the recalcitrant nature of dyes to biological oxidation, a tertiary treatment like adsorption is required. In the present study, unsaturated polyester resin (UPR) has been used as a sorbent in the treatment of dye-contaminated water. Different concentrations of Tropaeoline 000 containing water were treated with UPR. The preliminary investigations were carried out by batch adsorption to examine the effects of pH, adsorbate concentration, adsorbent dosage, contact time, and temperature. A plausible mechanism for the ongoing adsorption process and thermodynamic parameters have also been obtained from Langmuir and Freundlich adsorption isotherm models. Thermodynamic parameter showed that the sorption process of Tropaeoline 000 onto activated carbon (AC) and UPR were feasible, spontaneous, and endothermic under studied conditions. The estimated values for (?G) are -10.48?×?10(3) and -6.098?×?10(3) kJ mol(-1) over AC and UPR at 303 K (30 °C), indicating towards a spontaneous process. The adsorption process followed pseudo-first-order model. The mass transfer property of the sorption process was studied using Lagergren pseudo-first-order kinetic models. The values of % removal and k (ad) for dye systems were calculated at different temperatures (303-323 K). The mechanism of the adsorption process was determined from the intraparticle diffusion model. PMID:22689095

Jain, Rajeev; Sharma, Pooja; Sikarwar, Shalini

2013-03-01

350

DC-electrical conductivity as a method for monitoring radiation curing of unsaturated polyester resins III. Evaluation of results  

NASA Astrophysics Data System (ADS)

The results of DC-electrical conductivity monitoring of radiation and thermally initiated crosslinking of unsaturated polyester resins are interpreted using conductivity data itself instead of commonly used logarithmic data form. The main setbacks of logarithmic conductivity data were the shift toward longer reaction time compared to non-logarithmic conductivity data and extraction analysis results and pronounced scattering at the end of the reaction so it was impossible to detect vitrification point. By revision of approach to analysis of results, full sensitivity of the electrical conductivity method to structural changes in the reacting system was shown. The apparent rate constants calculated from conductivity itself showed the influence of upper liquid-liquid transition on the rate of radiation induced reaction that could not be seen if the logarithm of conductivity was used. Influence of dose rate effects and electrical field effects on reaction rate were detected too and confirmed by DSC measurements. All details of reaction can be detected using first derivative of conductivity and in the case of thermally initiated reaction two maxims of reaction rate were found that are probably caused by local increase of temperature due to highly exothermic reaction.

Puci?, Irina; Ranogajec, Franjo

1999-01-01

351

The role of polyester interstitium and aldosterone during structural development of renal tubules in serum-free medium.  

PubMed

Little knowledge is available regarding the development of renal stem/progenitor cells into functional parenchyme. To investigate the environmental mechanisms during this maturation process, we elaborated an advanced culture technique to follow renal tubule development. Embryonic stem/progenitor cells derived from neonatal rabbit kidney were placed in a perfusion culture container at the interphase of an artificial polyester interstitium. Tissue culture was carried out in IMDM without serum or protein supplementation and without coating with extracellular matrix proteins. Development of tubules was registered histochemically on cryosections labeled with soybean agglutinin (SBA) and tissue-specific antibodies. The experiments revealed that the development of renal tubules depends exclusively on the administration of aldosterone. The use of 1x10(-7) M aldosterone for 13 days generated numerous SBA-labeled tubules, while no tubules developed in the absence of the steroid hormone. To obtain further information about the action of the hormone on the cognate receptor, molecular precursors of the aldosterone synthesis pathway were tested. Surprisingly, application of cholesterol, pregnenolone, progesterone, 11-deoxycorticosterone (DOCA) and corticosterone failed to form numerous tubules. Only 11-DOCA and progesterone induced a few tubules, which were barely SBA-labeled. Furthermore, application of aldosterone antagonists such as 1x10(-4) M spironolactone and 1x10(-4) M canrenoate completely inhibited the development of tubules. We conclude that specifically aldosterone promotes the development of tubules via the mineralocorticoid receptor whereas its precursors have no effect. PMID:17643487

Minuth, Will W; Denk, Lucia; Hu, Kanghong

2007-10-01

352

Transparent Thin Films Deposited onto Polyester Film Substrate by Radio Frequency Sputtering with a Poly(tetrafluoroethylene) Target  

NASA Astrophysics Data System (ADS)

Improvement technologies for antireflection property of transparent plastic substrates are required in computer displays. Inorganic coatings have been used to reduce the surface reflection. We have already reported that fluorocarbon thin films sputtered with a poly(tetrafluoroethylene) (PTFE) target are transparent and can be used for an antireflection film, although the pristine PTFE plate used for the sputtering target is white. The fluorocarbon thin films were deposited onto a polyester (PET) film substrate by an rf sputtering, and characterized their optical properties. Elemental ratio, fluorine for carbon, of the thin films increased and degree of cross-linking of the thin films decreased with an increase of the rf power. Arithmetical surface roughness of the fluorocarbon thin films slightly increased with an increase of the rf power. Surface roughness of the fluorocarbon thin film affects the transmittance as well as the chemical structure of the thin film. To enhance the transparency, the diffuse transmittance should be suppressed, and flat surface thin films should be prepared by the sputtering at lower rf power and pressure.

Seino, Shou; Nagai, Yuki; Kobayashi, Masashi; Iwamori, Satoru; Noda, Kazuhiro

2013-05-01

353

Biobased polyesters with composition-dependent thermomechanical properties: synthesis and characterization of poly(butylene succinate-co-butylene azelate).  

PubMed

Environmentally friendly poly(butylenesuccinate-co-butyleneazelate) (P(BS-co-BAz)s) aliphatic copolyesters with composition-dependent thermomechanical properties were synthesized from succinic acid (SuA), 1,4-butanediol (BDO), and dimethylazelate (DMAz) through a two-step polycondensation reaction. The molar SuA/AzA ratio was varied from 4:1 to 1:4, and the chemical structure and molecular characteristics of resulting (co)polyesters were characterized by NMR and SEC, whereas thermal properties and crystallinity were studied by differential scanning calorimetry (DSC), dynamic mechanical thermal analyses (DMTA), and X-ray diffraction (XRD). A good agreement between theoretical and experimental SuA/AzA molar ratios in the copolyesters was achieved, together with the recovery of semicrystalline random copolymers of uniform composition along the chains. NMR, DSC, DMTA, and XRD results show that depending on their composition the P(BS-co-BAz) copolyesters might find applications from elastomers to high-impact thermoplastics. PMID:23369072

Mincheva, Rosica; Delangre, Adrien; Raquez, Jean-Marie; Narayan, Ramani; Dubois, Philippe

2013-03-11

354

Cost of mask fabrication  

NASA Astrophysics Data System (ADS)

The development of the cost of ownership methodology provided the semiconductor industry with a process that is employed to evaluate the life cycle costs of any particular equipment. Applying this technique has provided a cost focus on areas of potential improvement. The existing methodology is equipment centric. The limitation of this process is that there has not been a means of evaluating the impact of the cost of ownership for a process. An evaluation of process requirements indicated that such a tool would provide an advantage for evaluating not only the process flow cost but also allocate the individual cost of ownership values according to the planned volumes and yields. This would not be the comprehensive evaluation that can be done with dynamic simulation, but a static first approximation at total process costs based on a combined process flow. This paper describes the application of this new process to the development of the process cost of ownership to the optical mask production process. The program employed in work, PRO COOLTM, was developed by WWK in conjunction with SEMATECH. This paper describes the application of process cost of ownership to the optical mask production process sequence. Using a generic mask fabrication flow, process sequence cost of ownership analysis is used to identify cost drivers, throughput limitations, and process cost sensitivities. This generic process flow consists of the data evaluation and general number crunching requirements at the beginning of the process, followed by exposure, develop, inspection, measure, CD, pelliclize, inspect, and ship. Understanding of the relationship of these factors will help evaluate future mask fabrication technologies and requirements. Analyzing a generic optical mask production process sequence showed that the simple approach of adding process step cost of ownership values underestimates the process cost of ownership. Thus a complete analysis must consider the cost of unused capacity in the process sequence. The cost of unused capacity is correlated to the production throughput rate of the bottleneck tool. Capacity analysis helps to identify the bottleneck tool under static conditions, however, process and reliability variation can create short-term bottlenecks which must also be considered.

Trybula, Walter J.; Dance, Daren L.

1997-07-01

355

Space fabrication demonstration system composite beam cap fabricator  

NASA Technical Reports Server (NTRS)

A detailed design for a prototype, composite beam cap fabricator was established. Inputs to this design included functional tests and system operating requirements. All required materials were procured, detail parts were fabricated, and one composite beam cap forming machine was assembled. The machine was demonstrated as a stand-alone system. Two 12-foot-long beam cap members were fabricated from laminates graphite/polysulfane or an equivalent material. One of these members, which as structurally tested in axial compression, failed at 490 pounds.

1982-01-01

356

Fabrication of cotton fabric with superhydrophobicity and flame retardancy.  

PubMed

A simple and facile method for fabricating the cotton fabric with superhydrophobicity and flame retardancy is described in the present work. The cotton fabric with the maximal WCA of 160° has been prepared by the covalent deposition of amino-silica nanospheres and the further graft with (heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane. The geometric microstructure of silica spheres was measured by transmission electron microscopy (TEM). The cotton textiles before and after treatment were characterized by using scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The wetting behavior of cotton samples was investigated by water contact angle measurement. Moreover, diverse performances of superhydrophobic cotton textiles have been evaluated as well. The results exhibited the outstanding superhydrophobicity, excellent waterproofing durability and flame retardancy of the cotton fabric after treatment, offering a good opportunity to accelerate the large-scale production of superhydrophobic textiles materials for new industrial applications. PMID:23768579

Zhang, Ming; Wang, Chengyu

2013-07-25

357

Electrophoretic Deposition for Fabricating Microbatteries  

NASA Technical Reports Server (NTRS)

An improved method of fabrication of cathodes of microbatteries is based on electrophoretic deposition. Heretofore, sputtering (for deposition) and the use of photoresist and liftoff (for patterning) have been the primary methods of fabricating components of microbatteries. The volume of active electrode material that can be deposited by sputtering is limited, and the discharge capacities of prior microbatteries have been limited accordingly. In addition, sputter deposition is slow. In contrast, electrophoretic deposition is much faster and has shown promise for increasing discharge capacities by a factor of 10, relative to those of microbatteries fabricated by prior methods.

West, William; Whitacre, Jay; Bugga, Ratnakumar

2003-01-01

358

Mesoscale fabrication and design  

NASA Astrophysics Data System (ADS)

A strong link between mechanical engineering design and materials science and engineering fabrication can facilitate an effective and adaptable prototyping process. In this dissertation, new developments in the lost mold-rapid infiltration forming (LM-RIF) process is presented which demonstrates the relationship between these two fields of engineering in the context of two device applications. Within the LM-RIF process, changes in materials processing and mechanical design are updated iteratively, often aided by statistical design of experiments (DOE). The LM-RIF process was originally developed by Antolino and Hayes et al to fabricate mesoscale components. In this dissertation the focus is on advancements in the process and underlying science. The presented advancements to the LM-RIF process include an augmented lithography procedure, the incorporation of engineered aqueous and non-aqueous colloidal suspensions, an assessment of constrained drying forces during LM-RIF processing, mechanical property evaluation, and finally prototype testing and validation. Specifically, the molding procedure within the LM-RIF process is capable of producing molds with thickness upwards of 1mm, as well as multi-layering to create three dimensional structures. Increasing the mold thickness leads to an increase in the smallest feature resolvable; however, the increase in mold thickness and three dimensional capability has expanded the mechanical design space. Tetragonally stabilized zirconia (3Y-TZP) is an ideal material for mesoscale instruments, as it is biocompatible, exhibits high strength, and is chemically stable. In this work, aqueous colloidal suspensions were formulated with two new gel-binder systems, increasing final natural orifice translumenal endoscopic surgery (NOTES) instrument yield from 0% to upwards of 40% in the best case scenario. The effects of the gel-binder system on the rheological behavior of the suspension along with the thermal characteristics of the gel-binder system were characterized. Finally, mechanical properties of ceramic specimens were obtained via 3-point bend testing. Another candidate material for NOTES devices as well as cellular contact aided compliant mechanisms (C3M) devices is 300 series stainless steel (300 series stainless steel). 300 series stainless steel is a common biocompatible material; it is used in surgical applications, exhibits a high corrosion resistance, and has high strength to failure. New, high solids loading, non-aqueous colloidal suspensions of 300 series stainless steel were formulated and incorporated into the LM-RIF process. The rheological behavior and thermal characteristics of the non-aqueous colloidal suspensions were analyzed and engineered to operate within the LM-RIF process. Final part yield with the non-aqueous colloidal suspensions was higher than that of the aqueous ceramic suspensions. Mechanical properties of 300 series stainless steel specimens were determined via 3-point bend testing. Furthermore, new composite non-aqueous colloidal suspensions of 3Y-TZP and 300 series stainless steel were formulated and incorporated into the LM-RIF process. The composite materials showed an increase in final part yield, and an increase in yield strength compared to pure 300 series stainless steel was determined by Vickers hardness testing. The successful incorporation of composite suspensions in the LM-RIF process was facilitated through an analysis of the rheological behavior as a function of solids loading and ceramic to metal ratio. Optimized designs of NOTES instruments, as well as C3M devices were manufactured using the LM-RIF process with the non-aqueous 300 series stainless steel suspension. The performance of the prototype NOTES instruments was evaluated and compared against the theoretically predicted performance results, showing good agreement. Similarly, good agreement was seen between the stress-displacement behavior of prototype C3M devices when compared to the theoretically calculated stress-displacement results. Finally, in a comparison by endoscopic surgeons a

Hayes, Gregory R.

359

The structure of airplane fabrics  

NASA Technical Reports Server (NTRS)

This report prepared by the Bureau of Standards for the National Advisory Committee for Aeronautics supplies the necessary information regarding the apparatus and methods of testing and inspecting airplane fabrics.

Walen, E Dean

1920-01-01

360

Film Fabrication Technologies at NREL  

NASA Technical Reports Server (NTRS)

The National Renewable Energy Laboratory (NREL) has extensive capabilities for fabricating a variety of high-technology films. Much of the in-house work in NREL's large photovoltaics (PV) program involves the fabrication of multiple thin-film semiconducting layers constituting a thin-film PV device. NREL's smaller program in superconductivity focuses on the fabrication of superconducting films on long, flexible tape substrates. This paper focuses on four of NREL's in-house research groups and their film fabrication techniques, developed for a variety of elements, alloys, and compounds to be deposited on a variety of substrates. As is the case for many national laboratories, NREL's technology transfer efforts are focusing on Cooperative Research and Development Agreements (CRADA's) between NREL researchers and private industry researchers.

Mcconnell, Robert D.

1993-01-01

361

Underwater Robotics: Science, Design & Fabrication  

NSDL National Science Digital Library

This website includes information on the textbook Underwater Robotics: Science, Design & Fabrication by Steven W. Moore, Harry Bohm and Vickie Jensen. The site includes information about the content of the book as well as sample material.

2011-09-20

362

Fabrication of nanopore on pyramid  

NASA Astrophysics Data System (ADS)

There have been tremendous interests about the fabrication of metallic nanopore due to the ultrafast genome sequencing biosensor capability. In this report, the fabrication of the nanopore on the Au coated SiO2 pyramid has been examined using various high energy electron beam irradiation and focused ion beam (FIB) milling techniques. The microfabricated Au nano-apertures on pyramid were irradiated with various high energy electron beam and FIB techniques. The formation of the nanopore dependent on the probe current was also examined using electron probe micro-analysis (EPMA). The nanopore on the Au coated SiO2 pyramid is found to be an Ausbnd Si mixture. The Au nanopore on the crater type hole was also fabricated using FIB Ga ion beam scanning. The shrinking rate was found to be the fastest compared with those fabricated with the other electron beam techniques.

Choi, Seong Soo; Park, Myong-Jin; Yamaguchi, Tokutaro; Kim, Sung-In; Park, Kyung-Jin; Park, Nam Kyoo

2014-08-01

363

Silicon, iron and titanium doped calcium phosphate-based glass reinforced biodegradable polyester composites as bone analogous materials  

NASA Astrophysics Data System (ADS)

Bone defects resulting from disease or traumatic injury is a major health care problem worldwide. Tissue engineering offers an alternative approach to repair and regenerate bone through the use of a cell-scaffold construct. The scaffold should be biodegradable, biocompatible, porous with an open pore structure, and should be able to withstand the applied forces. Phosphate-based glasses (PGs) may be used as reinforcing agents in degradable composites since their degradation can be predicted and controlled through their chemistry. This doctoral dissertation describes the development and evaluation of PGs reinforced biodegradable polyesters for intended applications in bone augmentation and regeneration. This research was divided into three main objectives: 1) Investigating the composition dependent properties of novel PG formulations by doping a sodium-free calcium phosphate-based glass with SiO2, Fe2O3, and TiO2. Accordingly, (50P2 O5-40CaO- xSiO2-(10-x)Fe2O3, where x = 10, 5 and 0 mol.%) and (50P2O5-40CaO-xSiO 2-(10-x)TiO2 where x = 10, 7, 5, 3 and 0 mol.%) formulations were developed and characterised. SiO2 incorporation led to increased solubility, ion release, pH reduction, as well as hydrophilicity, surface energy, and surface polarity. In contrast, doping with Fe2O 3 or TiO2 resulted in more durable glasses, and improved cell attachment and viability. It was hypothesised that the presence of SiO 2 in the TiO2-doped formulations could up-regulate the ionic release from the PG leading to higher alkaline phosphatase activity of MC3T3-E1 cells. 2) Incorporating Si, Fe, and Ti doped PGs as fillers, either as particulates (PGPs) or fibres (PGFs), into biodegradable polyesters (polycaprolactone (PCL) and semi-crystalline and amorphous poly(lactic acid) (PLA and PDLLA)) with the aim of developing degradable bone analogous composites. It was found that PG composition and geometry dictated the weight loss, ionic release, and mechanical properties of the composites. It was also hypothesised that a potential reaction between Si and the ester bond led to the formation of carboxylate by-products resulting in a lower molecular weight polymer, thus affecting the mechanical properties of the composites. Cytocompatibility assessment with MC3T3-E1 pre-osteoblasts showed that these composites were cytocompatible, and cell alignment along the PGFs was observed possibly due to their favourable ionic release properties. 3) Investigating the solid-state foaming using carbon dioxide (CO 2) of PDLLA-PGP composites with up to 30 vol.% filler content. While PDLLA foams resulted in 92% porosity, the porosity of the composites ranged between 79 and 91% which decreased with PGP content. In addition, a reduction in pore size was observed with increasing PGP content; however, the pore size maintained its range of 200-500 ?m in all composite foams, suitable for bone tissue engineering applications. The percentage of open pores increased significantly with PGP content (up to 78% at 30 vol.% PGP). Compressive strength and modulus of PDLLA-PGP foams showed up to approximately 3-fold increase at 30 vol.% PGP content compared to neat PDLLA foams.

Shah Mohammadi, Maziar

364

Plasma Processes for Semiconductor Fabrication  

Microsoft Academic Search

Plasma processing is a central technique in the fabrication of semiconductor devices. This self-contained book provides an up-to-date description of plasma etching and deposition in semiconductor fabrication. It presents the basic physics and chemistry of these processes, and shows how they can be accurately modeled. The author begins with an overview of plasma reactors and discusses the various models for

W. N. G. Hitchon

1999-01-01

365

Properties of Fibers and Fabrics  

NSDL National Science Digital Library

This learning activity tests the strength of fibers and fabrics: specifically, threads, string and yarn made from a variety of materials. The experiment will demonstrate the particular properties of different fibers and fabrics and the differences between natural and synthetic fibers. This activity would be suitable for high school and introductory college undergraduate students. The lesson should take two class periods to complete in full. This document will serve as a framework for instructors and may be downloaded in PDF format.

Ferguson, Luke

2012-10-03

366

Bacterial Polyester Inclusions Engineered To Display Vaccine Candidate Antigens for Use as a Novel Class of Safe and Efficient Vaccine Delivery Agents?  

PubMed Central

Bioengineered bacterial polyester inclusions have the potential to be used as a vaccine delivery system. The biopolyester beads were engineered to display a fusion protein of the polyester synthase PhaC and the two key antigens involved in immune response to the infectious agent that causes tuberculosis, Mycobacterium tuberculosis, notably antigen 85A (Ag85A) and the 6-kDa early secreted antigenic target (ESAT-6) from Mycobacterium tuberculosis. Polyester beads displaying the respective fusion protein at a high density were successfully produced (henceforth called Ag85A-ESAT-6 beads) by recombinant Escherichia coli. The ability of the Ag85A-ESAT-6 beads to enhance mouse immunity to the displayed antigens was investigated. The beads were not toxic to the animals, as determined by weight gain and absence of lesions at the inoculation site in immunized animals. In vivo injection of the Ag85A-ESAT-6 beads in mice induced significant humoral and cell-mediated immune responses to both Ag85A and ESAT-6. Vaccination with Ag85A-ESAT-6 beads was efficient at stimulating immunity on their own, and this ability was enhanced by administration of the beads in an oil-in-water emulsion. In addition, vaccination with the Ag85A-ESAT-6 beads induced significantly stronger humoral and cell-mediated immune responses than vaccination with an equivalent dose of the fusion protein Ag85A-ESAT-6 alone. The immune response induced by the beads was of a mixed Th1/Th2 nature, as assessed from the induction of the cytokine gamma interferon (Th1 immune response) and increased levels of immunoglobulin G1 (Th2 immune response). Hence, engineered biopolyester beads displaying foreign antigens represent a new class of versatile, safe, and biocompatible vaccines. PMID:19837843

Parlane, Natalie A.; Wedlock, D. Neil; Buddle, Bryce M.; Rehm, Bernd H. A.

2009-01-01

367

CYP86B1 Is Required for Very Long Chain ?-Hydroxyacid and ?,?-Dicarboxylic Acid Synthesis in Root and Seed Suberin Polyester1[W][OA  

PubMed Central

Suberin composition of various plants including Arabidopsis (Arabidopsis thaliana) has shown the presence of very long chain fatty acid derivatives C20 in addition to the C16 and C18 series. Phylogenetic studies and plant genome mining have led to the identification of putative aliphatic hydroxylases belonging to the CYP86B subfamily of cytochrome P450 monooxygenases. In Arabidopsis, this subfamily is represented by CYP86B1 and CYP86B2, which share about 45% identity with CYP86A1, a fatty acid ?-hydroxylase implicated in root suberin monomer synthesis. Here, we show that CYP86B1 is located to the endoplasmic reticulum and is highly expressed in roots. Indeed, CYP86B1 promoter-driven ?-glucuronidase expression indicated strong reporter activities at known sites of suberin production such as the endodermis. These observations, together with the fact that proteins of the CYP86B type are widespread among plant species, suggested a role of CYP86B1 in suberin biogenesis. To investigate the involvement of CYP86B1 in suberin biogenesis, we characterized an allelic series of cyp86B1 mutants of which two strong alleles were knockouts and two weak ones were RNA interference-silenced lines. These root aliphatic plant hydroxylase lines had a root and a seed coat aliphatic polyester composition in which C22- and C24-hydroxyacids and ?,?-dicarboxylic acids were strongly reduced. However, these changes did not affect seed coat permeability and ion content in leaves. The presumed precursors, C22 and C24 fatty acids, accumulated in the suberin polyester. These results demonstrate that CYP86B1 is a very long chain fatty acid hydroxylase specifically involved in polyester monomer biosynthesis during the course of plant development. PMID:19525321

Compagnon, Vincent; Diehl, Patrik; Benveniste, Irène; Meyer, Denise; Schaller, Hubert; Schreiber, Lukas; Franke, Rochus; Pinot, Franck

2009-01-01

368

Nondestructive Identification of Dye Mixtures in Polyester and Cotton Fibers Using Raman Spectroscopy and Ultraviolet-Visible (UV-Vis) Microspectrophotometry.  

PubMed

Presented in this paper is an assessment of the applicability of Raman spectroscopy and microspectrophotometry (MSP) in visible and ultraviolet light (UV-Vis) in the examination of textile fibers dyed with mixtures of synthetic dyes. Fragments of single polyester fibers, stained with ternary mixtures of disperse dyes in small mass concentrations, and fragments of single cotton fibers, dyed with binary or ternary mixtures of reactive dyes, were subjected to the study. Three types of excitation sources, 514, 633, and 785 nm, were used during Raman examinations, while the MSP study was conducted in the 200 to 800 nm range. The results indicate that the capabilities for discernment of dye mixtures are similar in the spectroscopic methods that were employed. Both methods have a limited capacity to distinguish slightly dyed polyester fiber; additionally, it was found that Raman spectroscopy enables identification of primarily the major components in dye mixtures. The best results, in terms of the quality of Raman spectra, were obtained using an excitation source from the near infrared. MSP studies led to the conclusion that polyester testing should be carried out in the range above 310 nm, while for cotton fibers there is no limitation or restriction of the applied range. Also, MSP UV-Vis showed limited possibilities for discriminatory analysis of cotton fibers dyed with a mixture of reactive dyes, where the ratio of the concentration of the main dye used in the dyeing process to minor dye was higher than four. The results presented have practical applications in forensic studies, inter alia. PMID:25588115

Was-Gubala, Jolanta; Starczak, Roza

2015-02-01

369

The effect of spraying and rolling process factors on styrene emission during the application of unsaturated polyester resins.  

PubMed

In recent years the awareness of the problems caused by styrene emission during the processing of unsaturated polyester resins has enlarged. The spray-up application of gel coats is especially problematic, and it produces high styrene emission rates. The emission of styrene has been reduced through material changes, work practice controls, and add-on controls. However, the influence of the spray-up process factors on styrene emission has not been studied before. The aim of this study was to examine possibilities to reduce styrene emission by optimization of spray-up process factors. The following factors were studied under controlled laboratory conditions: orifice size and angle of the spray gun tip, spraying pressure, distance between spray gun and mold, and shape of the mold. The influence of the rolling pattern during lamination was also studied. Several significant factors were found. High pressure and long spraying distance increased both the unit styrene emission and the emission rate. The orifice size had two effects; a large orifice decreased the amount of styrene emitted per sprayed amount of resin but increased the emission rate of styrene. The shape of the mold did not affect the styrene emission. Styrene emission is greater if the entire mold area is rolled. To achieve lower emission is it necessary to roll an area as small as possible; this is especially important if a large mold is laminated. The results showed that emission of styrene can be reduced significantly by an optimal selection of the spray gun settings and the way of working. Optimal settings also increased the transfer efficiency resulting in decreased material loss. PMID:12486781

Säämänen, Arto; Skrifvars, Mikael

2002-01-01

370

Compare Fabric Materials. Grades 3-5.  

ERIC Educational Resources Information Center

In this activity, students look at different types of fabric and their respective individual properties. Using a magnifying glass and sandpaper, students test the weave and wear quality of sample fabrics. By comparing the qualities of different fabrics, they are able to better understand why there are so many different types of fabric and…

Rushton, Erik; Ryan, Emily; Swift, Charles

371

Fabric Performance in Clothing and Clothing Manufacture  

Microsoft Academic Search

After the performance of clothing fabric in use has been satisfied to some extent, consumers seek better-quality, that is, more comfortable, fabrics. Fabric performance in relation to ‘better fitting to the human body’ is an essential requirement of clothing materials. From the mechanical-comfort viewpoint, textile producers and consumers have evaluated this kind of fabric performance by a subjective method, called

S. Kawabata; Masako Niwa

1989-01-01

372

Fabric composite heat pipe technology development  

Microsoft Academic Search

Testing has been performed on a variety of fabric composite technology feasibility issues. These include an evaluation of the effective radiation heat transfer rate from a heated metallic surface covered by a ceramic fabric with the intent of determining the ``effective emissivity'' of the combination of materials, studies of the wicking properties of ceramic fabrics, and the construction of fabric

Andrew C. Klein; Zubaida Gulshan-Ara; William Kiestler; Ross Snuggerud; Timothy S. Marks

1993-01-01

373

A facile method to fabricate superhydrophobic cotton fabrics  

NASA Astrophysics Data System (ADS)

A facile and novel method for fabricating superhydrophobic cotton fabrics is described in the present work. The superhydrophobic surface has been prepared by utilizing cationic poly (dimethyldiallylammonium chloride) and silica particles together with subsequent modification of (heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane. The size distribution of silica particles was measured by Particle Size Analyzer. The cotton textiles before and after treatment were characterized by using scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The wetting behavior of cotton samples was investigated by water contact angle measurement. Moreover, the superhydrophobic durability of coated cotton textiles has been evaluated by exposure, immersion and washing tests. The results show that the treated cotton fabrics exhibited excellent chemical stability and outstanding non-wettability with the WCA of 155 ± 2°, which offers an opportunity to accelerate the large-scale production of superhydrophobic textiles materials for new industrial applications.

Zhang, Ming; Wang, Shuliang; Wang, Chengyu; Li, Jian

2012-11-01

374

Structure and yarn sensor for fabric  

DOEpatents

A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric.

Mee, David K. (Knoxville, TN); Allgood, Glenn O. (Powell, TN); Mooney, Larry R. (Knoxville, TN); Duncan, Michael G. (Clinton, TN); Turner, John C. (Clinton, TN); Treece, Dale A. (Knoxville, TN)

1998-01-01

375

Sacrificial bridges for MEMS fabrication  

NASA Astrophysics Data System (ADS)

This study discusses sacrificial bridges that are used to release MEMS devices. Before being released, sacrificial bridges connect all the component structures into an integral structure. Solder bump bonding is used to mount the MEMS chip on another chip or a printed circuit board (PCB) and to maintain the alignment among all component structures after removal of the sacrificial bridges. Two types of sacrificial bridges were designed, analyzed and fabricated. The fabrication process—which used low resistivity single crystal silicon (SCS) wafers as the device material—was developed to implement the sacrificial bridges. Novel SCS through silicon vias (TSVs), which interconnect stacked chips, was made using the same process. An electrostatic comb drive actuator was fabricated and mounted onto a PCB. The fabricated actuator was tested to demonstrate the feasibility of the fabrication process, sacrificial bridges and SCS TSVs. The results show that the actuator worked well. Its maximum displacement and resonant frequency were 69.9 µm and 406 Hz, respectively. This method is promising for the delivery of a novel 3D system in package for MEMS devices.

Chang, Chao-Min; Chen, Yang-Che; Fong, Chien-Fu; Guu, Yunn-Horng; Chen, Rongshun; Yeh, J. Andrew; Hou, Max T.

2011-09-01

376

Effects of hydrophobic drug polyesteric core interactions on drug loading and release properties of poly(ethylene glycol) polyester poly(ethylene glycol) triblock core shell nanoparticles  

NASA Astrophysics Data System (ADS)

BAB amphiphilic triblock copolymers consisting of poly(ethylene glycol) (B) (PEG) as the hydrophilic segment and different polyesters (A) as the hydrophobic block were prepared by a polycondensation reaction as efficient model core-shell nanoparticles to assay the effect of interactions between the hydrophobic drug and the polyesteric core in terms of drug loading content and release profile. PEG-poly(hexylene adipate)-PEG (PEG-PHA-PEG) and PEG-poly(butylene adipate)-PEG (PEG-PBA-PEG) to PEG-poly(ethylene adipate)-PEG (PEG-PEA-PEG) core-shell type nanoparticles entrapping quercetin (an anticarcinogenic, allergy inhibitor and antibacterial agent), were prepared by a nanoprecipitation method and characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM) and x-ray diffraction (XRD) techniques. It was found that the obtained nanoparticles showed a smooth surface and spherical shape with controllable sizes in the range of 64-74 nm, while drug loading varied from 7.24% to 19% depending on the copolymer composition and the preparation conditions. The in vitro release behaviour exhibited a sustained release and was affected by the polymer-drug interactions. UV studies revealed the presence of hydrogen bonding as the main existing interaction between quercetin and polyesters in the nanosphere cores.

Khoee, Sepideh; Hassanzadeh, Salman; Goliaie, Bahram

2007-05-01

377

[Dental resin for restoration with unsaturated polyester resin used as base material. Effect of catalyst, accelerator and subaccelerator on working time, setting time and peak temperature].  

PubMed

The fatal demerit of resin materials which causes a marginal sealing defect or marginal fracture is hard to eliminate. A series of studies seeking for dental resin for restoration having no polymerization shrinkage, applying polyester resin used as base resin. This study was conducted to promote the improvement of composite resin, in which the author examined the composition with catalyst, accelerator and subaccelerator having preferable working time, setting time and peak temperature which is not clear, so as to obtain the fundamental data. In accordance with the increase in the amount of catalyst, accelerator and subaccelerator added, peak temperature showed a tendency to increase. Contrarily, working time and setting time showed a tendency to decrease. The composition showing preferable working time, setting time and peak temperature, is as follows: to the base resin, polyester with 38 wt% of shrinkage inhibitor mixed, catalyst by 1.0 wt%, accelerator by 0.50 wt% and subaccelerator by 0.02 wt% were added. The trial product of composite resin a 70 wt% of surface-treated glass beads added showed a working time of 2.3 minutes, setting time of 9 minutes and peak temperature of 57.0 degrees C, approximately the same values as of commercial composite resin. PMID:2637500

Mayahara, N

1989-05-01

378

D.C.-electrical conductivity as a method for monitoring radiation curing of unsaturated polyester resins—II. Influence of electrical field and dose rate  

NASA Astrophysics Data System (ADS)

The course of radiation crosslinking of unsaturated polyester resins was followed by measuring electrical conductivity change. Both the electrical field strength and dose rate influenced the crosslinking. The electrical field somewhat increased the reaction rate possibly due to the orientation of a polar polyester chains. To investigate the effect of electrical field, the samples were irradiated to different doses at different field strengths, from 2.5 to 250 kV/m and then extracted in benzene to determine the extent of crosslinking. The extraction analysis of irradiated samples confirmed the influence of electrical field observed in conductivity measurements. The electrical field effect depended on the dose rate. Three dose rates were applied 3.05, 0.354 and 0.096 kGy/h. The medium dose rate gave the highest reaction rate (on dose scale). Faster decrease of free styrene content with radiation dose than increase of gel content at higher dose rate implies partial styrene graftng or homopolymerization. The higher the electrical field the more pronounced were the effects of dose rate.

Puci?, Irina; Ranogajec, Franjo

1996-06-01

379

Stirling Microregenerators Fabricated and Tested  

NASA Technical Reports Server (NTRS)

A mesoscale Stirling refrigerator patented by the NASA Glenn Research Center is currently under development. This refrigerator has a predicted efficiency of 30 percent of Carnot and potential uses in electronics, sensors, optical and radiofrequency systems, microarrays, and microsystems. The mesoscale Stirling refrigerator is most suited to volume-limited applications that require cooling below the ambient or sink temperature. Primary components of the planar device include two diaphragm actuators that replace the pistons found in traditional-scale Stirling machines and a microregenerator that stores and releases thermal energy to the working gas during the Stirling cycle. Diaphragms are used to eliminate frictional losses and bypass leakage concerns associated with pistons, while permitting reversal of the hot and cold sides of the device during operation to allow precise temperature control. Three candidate microregenerators were fabricated under NASA grants for initial evaluation: two constructed of porous ceramic, which were fabricated by Johns Hopkins Applied Physics Laboratory, and one made of multiple layers of nickel and photoresist, which was fabricated by Polar Thermal Technologies. The candidate regenerators are being tested by Johns Hopkins Applied Physics in a custom piezoelectric-actuated test apparatus designed to produce the Stirling refrigeration cycle. In parallel with the regenerator testing, Johns Hopkins is using deep reactive ion etching to fabricate electrostatically driven, comb-drive diaphragm actuators. These actuators will drive the Stirling cycle in the prototype device. The top photograph shows the porous ceramic microregenerators. Two microregenerators were fabricated with coarse pores and two with fine pores. The bottom photograph shows the test apparatus parts for evaluating the microregenerators, including the layered nickel-and-photoresist regenerator fabricated using LIGA techniques.

Moran, Matthew E.

2004-01-01

380

Optimizing and fabricating magnetocaloric materials  

NASA Astrophysics Data System (ADS)

The microstructural modification of existing materials for magnetic cooling applications, and mass fabrication of the modified materials are reviewed, emphasizing the maximization of magnetic entropy change and minimization of hysteresis losses, as well as the engineering problems in the actual application of promising materials. In the first part, physical rules are put forward to explore high performance magnetic refrigerants, including the enhancement of adiabatic temperature change in finite field, multi-caloric effects, and multi-layered structure. Special attention is given to non-magnetic properties. Following this, an overview of mass fabrication of magnetic refrigerants having large entropy change, small hysteresis, good mechanical properties, and high thermal conductivity is presented.

Liu, Jian

2014-04-01

381

Tissue reaction to fabrics coated with turbostratic carbon: subcutaneous versus vascular implants.  

PubMed

A technique allowing the deposition of an adherent thin film of turbostratic, high-density carbon on heat-sensitive polymers was recently developed. The biological response to this biomaterial on yarns and fabrics of the type used in cardiovascular surgery has been studied. Polyester yarns, knitted Dacron sheets and knitted uncrimped Dacron vascular grafts were coated with a thin film (less than 1 micron) of turbostratic carbon using a physical vapour deposition process. Coated and control discs of knitted material, as well as coated and uncoated yarns, were implanted in pairs in the subcutaneous tissue of mice, using for each type of implant two cohorts of 12 animals, with observation periods of 4 and 8 wks respectively. Vascular grafts (8 cm long, 8 mm i.d.) coated with carbon on the luminal side only, were implanted for 12 wks in the infrarenal aortic position in six dogs, and compared to uncoated Dacron grafts of the same dimensions inserted in the same location and for the same duration in the infrarenal aortic position in six control animals. With subcutaneous implants, there was no significant difference in the tissue reaction to either coated or uncoated patches. In contrast, the vascular grafts, all of which were patent upon retrieval, showed a much lower extent of thrombosis on the blood-exposure surface in the case of carbon-coated Dacron, as compared to the luminal surface of control prostheses. The internal capsule (tissue formed between the polymer fabric and the blood interface) was thinner in carbon-coated grafts than in control grafts.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2964876

Aebischer, P; Goddard, M B; Sasken, H F; Hunter, T J; Galletti, P M

1988-01-01

382

Design and fabrication of a rectenna system to be coupled to photovoltaic solar cells  

NASA Astrophysics Data System (ADS)

Inkjet-printed metamaterials and nanotechnology enabled flexible antennas fabricated on glass or polyester substrates help in further absorption of transmitted radiation through photovoltaic solar cells. Using metamaterials processed by inkjet printing and diffusing it, for a rectenna system coupled with photovoltaic solar cells, as rectifying antenna, an antenna in system in tandem is created. Metamaterials are artificial materials engineered to have properties that may not be found in nature (negative refractive index). When used in an antenna, they increase gain. For efficient solar cell use, nanophotonics on the incident surface or metamaterials under it as a rectenna, can enhance voltage gain in cloudy or rainy condition, which in turn increases the overall efficiency and reduces the amount of material required, thereby cutting costs. Photovoltaic is a field of technology and research related to practical application of photovoltaic cells in producing electricity from light. Cells are described as photovoltaic cells when the light source is not necessarily sunlight but can be lamplight, artificial light, or any other source used for detecting light or other electromagnetic radiation at different light intensity and producing voltage. These can be, for example, infrared detectors, or detectors for measurement of light intensity. Conventional solar cell films are typically manufactured using expensive and slow manufacturing methods, which rely on high-temperature fabrication and finicky `vacuum deposition' processes for depositing solar materials onto substrates (III-V elements). The resultant products are simply too thick to allow for transparency. An important consideration in the development of a commercially viable solar powered cell is the glass substrate. The learning process and skills involved in developing the antenna below a solar cell is a great experience in theory and practice. My main effort will be to design and check performance of different rectenna module designs.

Mossavat, Mazda

383

Periadventitial atRA citrate-based polyester membranes reduce neointimal hyperplasia and restenosis after carotid injury in rats.  

PubMed

Oral all-trans retinoic acid (atRA) has been shown to reduce the formation of neointimal hyperplasia; however, the dose required was 30 times the chemotherapeutic dose, which already has reported side effects. As neointimal formation is a localized process, new approaches to localized delivery are required. This study assessed whether atRA within a citrate-based polyester, poly(1,8 octanediolcitrate) (POC), perivascular membrane would prevent neointimal hyperplasia following arterial injury. atRA-POC membranes were prepared and characterized for atRA release via high-performance liquid chromatography with mass spectrometry detection. Rat adventitial fibroblasts (AF) and vascular smooth muscle cells (VSMC) were exposed to various concentrations of atRA; proliferation, apoptosis, and necrosis were assessed in vitro. The rat carotid artery balloon injury model was used to evaluate the impact of the atRA-POC membranes on neointimal formation, cell proliferation, apoptosis, macrophage infiltration, and vascular cell adhesion molecule 1 (VCAM-1) expression in vivo. atRA-POC membranes released 12 ?g of atRA over 2 wk, with 92% of the release occurring in the first week. At 24 h, atRA (200 ?mol/l) inhibited [(3)H]-thymidine incorporation into AF and VSMC by 78% and 72%, respectively (*P = 0.001), with negligible apoptosis or necrosis. Histomorphometry analysis showed that atRA-POC membranes inhibited neointimal formation after balloon injury, with a 56%, 57%, and 50% decrease in the intimal area, intima-to-media area ratio, and percent stenosis, respectively (P = 0.001). atRA-POC membranes had no appreciable effect on apoptosis or proliferation at 2 wk. Regarding biocompatibility, we found a 76% decrease in macrophage infiltration in the intima layer (P < 0.003) in animals treated with atRA-POC membranes, with a coinciding 53% reduction in VCAM-1 staining (P < 0.001). In conclusion, perivascular delivery of atRA inhibited neointimal formation and restenosis. These data suggest that atRA-POC membranes may be suitable as localized therapy to inhibit neointimal hyperplasia following open cardiovascular procedures. PMID:25239800

Gregory, Elaine K; Webb, Antonio R; Vercammen, Janet M; Flynn, Megan E; Ameer, Guillermo A; Kibbe, Melina R

2014-11-15

384

Helical assembly, liquid crystalline behavior and crystallization of a nonracemic chiral main-chain liquid crystalline polyester and its monomers  

NASA Astrophysics Data System (ADS)

In this thesis, A non-racemic chiral main-chain liquid crystalline (LC) polyester was synthesized from (R)-(-)-4'-{o-[2-( p-hydroxy-o-nitrophenyloxy)-1-propyloxy]-1-undecyloxy}-4-biphenyl carboxylic acid via an A-B type condensation polymerization. The polymer was abbreviated as PET(R*-11) where eleven is the number of methylene units in the chain backbone. PET(R*-11) exhibited a LC chiral smectic C (SC*), a chiral smectic A (SA*) and a twist grain boundary Smectic A (TGBA*) phase with increasing temperatures as identified by differential scanning calorimetry, polarized optical microscopy, and wide angle X-ray diffraction (WAXD). Flat-elongated lamellae were observed in transmission electron microscopy (TEM) for thin-film melt crystallized samples. Its crystal structure was determined to be a monoclinic basic unit cell with a = 1.03 nm, b = 0.47 nm, c = 6.43 nm and gamma = 83° via selected area electron diffraction (SAED), and these measurements were confirmed by two-dimensional WAXD fiber patterns. Furthermore, SAED results showed that two kinds of crystal twins existed in this polymer: "micro-twinning" within one single lamellar crystal and "rotation-twinning" between two lamellae. This rotation-twinning was possibly a result of a mechanism of a soft epitaxy between two contacting (001) folded surfaces along the (3¯10) planes. Right-handed helical lamellar crystals were also found under the same crystallization conditions, and their pitch lengths were on the micrometer scale as observed by TEM and atomic force microscopy. The helical crystal structure was found to be identical to that of the flat-elongated counterparts. Dendritic crystals with fractal geometry were also obtained as the result of diffusion-controlled crystal growth. The phase structures of two monomers of PET(R*-11) were studied. One of them has carboxylic acid end group (named as K11-acid), while another has ester end group (named as Kl 1-ester). Kl 1-ester does not show any LC behavior, while cholesteric phase and Sc* phases can be obtained in K11-acid. The hydrogen-bonding between two carboxylic acid groups of K11-acid plays an important role in its liquid crystal phase formation. No helical crystals were observed in the monomers. These results might suggest that the enhanced chirality strength in the polymer chain of PET(R*-11) stabilize the helical structure in highly ordered crystals.

Weng, Xin

385

Reduction of suture associated inflammation after 28 days using novel biocompatible pseudoprotein poly(ester amide) biomaterials.  

PubMed

Sutures elicit an inflammatory response, which may impede the healing process and result in wound complications. We recently reported a novel family of biocompatible, biodegradable polymers, amino acid-based poly(ester amide)s (AA-PEA), which we have shown to significantly attenuate the foreign body inflammatory response in vitro. Two types of AA-PEA (Phe-PEA and Arg-Phe-PEA) were used to coat silk or plain-gut sutures, which were implanted in the gluteus muscle of C57BL/6 mice, while the uncoated control sutures were implanted in the contralateral side. After 3, 7, 14, and 28 days the mean area of inflammation surrounding the sutures was compared. Phe-PEA coating of silk sutures significantly decreased inflammation compared with noncoated controls (67.8?±?17.4% after 3d [p?=?0.0014], 51.6?±?7.2% after 7d [p?

Hernandez, Karina A; Hooper, Rachel Campbell; Boyko, Tatiana; Golas, Alyssa R; van Harten, Michel; Wu, D Q; Weinstein, Andrew; Chu, C C; Spector, Jason A

2015-02-01

386

Simultaneous determination of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in food samples using a carbon composite electrode modified with Cu 3(PO 4) 2 immobilized in polyester resin  

Microsoft Academic Search

A simple electrochemical method was developed for the single and simultaneous determination of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in food samples using square-wave voltammetry (SWV). A carbon composite electrode modified (MCCE) with copper (II) phosphate immobilized in a polyester resin was proposed. The modified electrode allowed the detection of BHA and BHT at potentials lower than those observed

Kellen Heloizy Garcia Freitas; Orlando Fatibello-Filho

2010-01-01

387

Fabrication of Complex Metallic Nanostructures  

E-print Network

Fabrication of Complex Metallic Nanostructures by Nanoskiving Qiaobing Xu, Robert M. Rioux to generate "master" structures (that is, it does not re- quire the nanostructures to be written in a separate of copies of a nanostructure). It thus provides a new capability to nanofabrication. In this tech- nique, we

Prentiss, Mara

388

MCVD fiber fabrication system design  

Microsoft Academic Search

The MCVD system for optical fiber fabrication was newly designed. A machine aided improved MCVD system was investigated, which consists of a precise glass working lathe, a stabilized gas blender, an oxy-hydrogen flame controller and a silica tube diameter controller. In addition, a computer controller is applicable for use to control the above mentioned system components. With this improved MCVD

K. Chida; Y. Terunuma; T. Edahiro; M. Okada

1979-01-01

389

ELECTROSTATIC STIMULATION OF FABRIC FILTRATION  

EPA Science Inventory

The paper gives results of an investigation of the concept of electrostatic stimulation of fabric filtration (ESFF) at pilot scale. The pilot unit consisted of a conventional baghouse in parallel with an ESFF baghouse, allowing direct comparison. Reported results are for pulse-cl...

390

FABRIC FILTER MODEL SENSITIVITY ANALYSIS  

EPA Science Inventory

The report gives results of a series of sensitivity tests of a GCA fabric filter model, as a precursor to further laboratory and/or field tests. Preliminary tests had shown good agreement with field data. However, the apparent agreement between predicted and actual values was bas...

391

Laser target fabrication, structure and method for its fabrication  

DOEpatents

The disclosure is directed to a laser target structure and its method of fabrication. The target structure comprises a target plate containing an orifice across which a pair of crosshairs are affixed. A microsphere is affixed to the crosshairs and enclosed by at least one hollow shell comprising two hemispheres attached together and to the crosshairs so that the microsphere is juxtapositioned at the center of the shell.

Farnum, Eugene H. (Los Alamos, NM); Fries, R. Jay (Los Alamos, NM)

1985-01-01

392

PROCEDURES MANUAL FOR FABRIC FILTER EVALUATION  

EPA Science Inventory

The report describes methods to be used in experimentally characterizing the performance of fabric filters for pollution control. It gives a detailed description of the mechanical characteristics of fabric filters. It describes procedures for measuring particle size distribution,...

393

A continuum model for needlepunched nonwoven fabrics  

E-print Network

Nonwoven fabrics are sheet structures created by bonding or interlocking a web (network) of fibers through mechanical, thermal or chemical processes. In general, the mechanical response of nonwoven fabrics exhibits two ...

Jearanaisilawong, Petch, 1979-

2008-01-01

394

Digital fabrication in the architectural design process  

E-print Network

Digital fabrication is affecting the architectural design process due to the increasingly important role it has in the fabrication of architectural models. Many design professionals, professors, and students have experienced ...

Seely, Jennifer C. K., 1975-

2004-01-01

395

14 CFR 31.35 - Fabrication methods.  

Code of Federal Regulations, 2010 CFR

...and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication used must produce a consistently...

2010-01-01

396

14 CFR 31.35 - Fabrication methods.  

Code of Federal Regulations, 2013 CFR

...and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication used must produce a consistently...

2013-01-01

397

14 CFR 31.35 - Fabrication methods.  

Code of Federal Regulations, 2012 CFR

...and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication used must produce a consistently...

2012-01-01

398

14 CFR 31.35 - Fabrication methods.  

Code of Federal Regulations, 2014 CFR

...and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication used must produce a consistently...

2014-01-01

399

14 CFR 31.35 - Fabrication methods.  

Code of Federal Regulations, 2011 CFR

...and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication used must produce a consistently...

2011-01-01

400

4.212 Design Fabrication, Spring 2003  

E-print Network

Design Fabrication is an introductory course in the field of advanced computing, prototyping and building fabrication. The class is focused on the relationship between design, various forms of computer modeling both explicit ...

Sass, Lawrence

401

Design System for Locally Fabricated Gallium Arsenide  

E-print Network

Design System for Locally Fabricated Gallium Arsenide Digital Integrated Circuits by Anthony Edward, 26 November, 1990 © Anthony Parker 1990 Gallium Arsenide Digital Integrated Circuits Project System for Locally Fabricated Gallium Arsenide Digital Integrated Circuits A thesis submitted to Sydney

402

Stir fabric phase sorptive extraction for the determination of triazine herbicides in environmental waters by liquid chromatography.  

PubMed

Stir fabric phase sorptive extraction (SFPSE), which integrates sol-gel hybrid organic-inorganic coated fabric phase sorptive extraction media with a magnetic stirring mechanism, is presented for the first time. Two flexible fabric substrates, cellulose and polyester were used as the host matrix for three different sorbents e.g., sol-gel poly(tetrahydrofuran), sol-gel poly(ethylene glycol), and sol-gel poly(dimethyldiphenylsiloxane). The new microextraction device has been analytically evaluated using triazine herbicides as model compounds. The factors affecting the extraction efficiency of SFPSE have been investigated and the optimal extraction conditions have been determined. Under these optimum conditions, the limits of quantification (LOQs) for sol-gel poly(ethylene glycol) coated SFPSE device in combination with UPLC-DAD for the analysis of the seven triazine herbicides were in the range of 0. 26-1.50?g/L with precision (relative standard deviation) at 2?g/L concentration ranging from 1.4-4.8% (intra-day, n=5) and 6.8-11.8% (inter-day, n=3). Enrichment factors were found between 444 and 1411 (compared to 2000 theoretical maximum). Absolute extraction recoveries were in the range of 22.2-70.5%. The developed method was applied for the determination of selected triazine herbicides from three river water samples. Relative recoveries of the target analytes, in the range from 75 to 126%, were found to be satisfactory. The combination of SFPSE with LC-MS/MS allows the improvement of the method sensitivity to the range from 0.015?g/L to 0.026?g/L with precision better than 10.8% expressed as relative standard deviation (RSD). PMID:25533394

Roldán-Pijuán, Mercedes; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel; Kabir, Abuzar; Furton, Kenneth G

2015-01-01

403

Freeform Fabrication of a Complete Electromechanical Relay  

Microsoft Academic Search

Research Paper Purpose We seek to produce electromechanical relays entirely via freeform fabrication as part of a larger effort to freeform fabricate complete electromechanical devices. Relays which can switch using an input current of less than 100 microamperes, gain greater than 10, and an open\\/closed resistance ratio of greater than 103 will make feasible the control of freeform fabricated actuators

Evan Malone; Hod Lipson

404

Fabric filters for the electric utility industry  

Microsoft Academic Search

Volume 3, Guidelines for Fabrics and Bags, provides a comprehensive guide for the procurement of fiberglass filter bags for utility baghouses. Utility baghouse operators must have a knowledge of fabric and bag construction to specify and obtain fiberglass filter bags that will provide food service in their baghouses. This volume describes the type of glass used in fabric filter bags,

L. G. Felix; K. M. Cushing; W. T. Grubb; D. V. Giovanni

1988-01-01

405

Beam builder for space fabrication  

NASA Technical Reports Server (NTRS)

Construction of a beam builder for producing triangular truss aluminum beams for use on large space structures is described. The machine will fabricate 0.04 cm thick 2024-T3 aluminum alloy into beams weighing 1.265 kg-m with side braces spot-welded to end caps to fabricate a triangular truss configuration up to 305 m long. The design characteristics, the electrical subsystems, the power requirements of the spot welding equipment, and the computer system for coordinating the motion of the Yoder rolling mills for forming caps from aluminum coils are described. Spot welding was compared with ultrasonic welding, stapling, wire stitching, riveting, grommets, stamp-lok, and pierce and fold joining methods with respect to ease of operation, safety, practicality, and ease of energy consumption. The beam builder will be evaluated to identify design requirements which can be utilized for the space flight version of its concept.

Ehl, J. H.; Irvine, C. N.; Williams, J. R.

1979-01-01

406

PRSEUS Panel Fabrication Final Report  

NASA Technical Reports Server (NTRS)

NASA and the Boeing Company have been working together under the Environmentally Responsible Aviation Project to develop stitched unitized structure for reduced weight, reduced fuel burn and reduced pollutants in the next generation of commercial aircraft. The structural concept being evaluated is PRSEUS (Pultruded Rod Stitched Efficient Unitized Structure). In the PRSEUS concept, dry carbon fabric, pultruded carbon rods, and foam are stitched together into large preforms. Then these preforms are infused with an epoxy resin into large panels in an out-of-autoclave process. These panels have stiffeners in the length-wise and width-wise directions but contain no fasteners because all stiffeners are stitched to the panel skin. This document contains a description of the fabrication of panels for use in the 30-foot-long Multi-Bay Box test article to be evaluated at NASA LaRC.

Linton, Kim A.; Velicki, Alexander; Hoffman, Krishna; Thrash, Patrick; Pickell, Robert; Turley, Robert

2014-01-01

407

RGD decoration of PEGylated polyester nanocapsules of perfluorooctyl bromide for tumor imaging: influence of pre or post-functionalization on capsule morphology.  

PubMed

PEGylated polyester nanocapsules of perfluorooctyl bromide (PFOB) were surface-decorated with a RGD (arginine-glycine-aspartic acid) peptide by either pre-functionalization or post-functionalization strategies using carbodiimide-assisted chemistry. Both strategies allowed successful linkage of RGD at the surface of nanocapsules with up to 600-950 peptide units per nanocapsule without modifying the encapsulation efficacy of PFOB used as the (19)F MRI imaging moiety. Cryo-Transmission Electron Microscopy images evidence that slight changes of the polymer used to form the capsule shell strongly influence nanocapsule morphology. While, the use of copolymer blends induces the formation of acorn morphologies, PLA-b-PEG-COOH leads to elongated and "tears of wine"-like nanoconstructs. In vivo evaluation in mice bearing CT26 tumors by (19)F MRI reveals no significant difference of accumulation between PEGylated and RGD-decorated nanocapsules obtained by the post-functionalization approach (highest RGD density/capsule). PMID:24333400

Diou, Odile; Fattal, Elias; Delplace, Vianney; Mackiewicz, Nicolas; Nicolas, Julien; Mériaux, Sébastien; Valette, Julien; Robic, Caroline; Tsapis, Nicolas

2014-05-01

408

d.c.-Electrical conductivity as a method for monitoring radiation curing of unsaturated polyester resins—I. Measurement conditions and comparison with extraction analysis data  

NASA Astrophysics Data System (ADS)

Radiation curing of unsaturated polyester resin with styrene was chosen to test the d.c.-electrical conductivity method for in-source monitoring of the curing reaction. The dependence of electrical conductivity on electrical field strength and temperature were tested to determine the optimal experimental conditions. The relationship between changes of electrical conductivity and the extent of crosslinking in the resin was determined by the extraction of the soluble fraction from the samples irradiated to different doses for which the change of electrical conductivity was determined previously. Good correlation was found between the extent of the reaction as assessed from both the mass of gel and the UV absorption of unreacted styrene and the results of electrical measurements.

Puci?, Irina; Ranogajec, Franjo

1995-09-01

409

Depolymerization of unsaturated polyesters and waste fiber-reinforced plastics by using ionic liquids: the use of microwaves to accelerate the reaction rate.  

PubMed

Waste fiber-reinforced plastics (FRP) and unsaturated polyesters were readily depolymerized by subjecting them to a treatment with ionic liquids under heating conditions. The use of microwaves for heating effectively progressed depolymerization, whereas the conventional heating method was ineffective for this purpose. We isolated the monomeric material, phthalic anhydride, by direct distillation from the reaction pot under reduced pressure with yields of more than 90%. We recovered the glass fibers in a pure form and achieved the effective removal of polystyrene, the linker unit of FRP. Ionic liquids were useful for several iterations of the reaction, and purification of the used ionic liquids was also possible. Thus, we developed a new use of ionic liquids for chemical recycling of waste plastics. PMID:21557493

Kamimura, Akio; Yamamoto, Shigehiro; Yamada, Kazuo

2011-05-23

410

Fabricated lightweight metal optic substrates  

Microsoft Academic Search

Brazing technology and lightweight beryllium detail components have been combined to produce ultra-lightweight beryllium optical substrates. The fabrication of such substrates is outlined noting: (1) conventional machining with midpoint braze joints, (2) machining the web wall to .030-inch or less and brazing to a splitter plate at midsection, and (3) producing a core element from commercially available sheet material: i.e.,

L. A. Grant

1978-01-01

411

Fabrication of simulated DUPIC fuel  

Microsoft Academic Search

Simulated DUPIC fuel provides a convenient way to investigate the DUPIC fuel properties and behavior such as thermal conductivity,\\u000a thermal expansion, fission gas release, leaching, and so on without the complications of handling radioactive materials. Several\\u000a pellets simulating the composition and microstructure of DUPIC fuel are fabricated by resintering the powder, which was treated\\u000a through OREOX process of simulated spent

Kweon Ho Kang; Ki Chan Song; Hee Sung Park; Je Sun Moon; Myung Seung Yang

2000-01-01

412

Structural colors, cosmetics, and fabrics  

NASA Astrophysics Data System (ADS)

Structural colors are non-pigment colors that originate from the scattering of light from ordered microstructures, thin films, and even irregular arrays of scatterers. Examples include the flashing sparks of colors in opals and the brilliant hues of some butterflies such as Morpho rhetenor. Structural colors arise in nature from one or more of a palette of physical mechanisms that are now understood quite well and can be implemented industrially to produce structurally colored paints, fabrics, and cosmetics.

Dushkina, Natalia; Lakhtakia, Akhlesh

2009-08-01

413

Micro Machining Enhances Precision Fabrication  

NASA Technical Reports Server (NTRS)

Advanced thermal systems developed for the Space Station Freedom project are now in use on the International Space Station. These thermal systems employ evaporative ammonia as their coolant, and though they employ the same series of chemical reactions as terrestrial refrigerators, the space-bound coolers are significantly smaller. Two Small Business Innovation Research (SBIR) contracts between Creare Inc. of Hanover, NH and Johnson Space Center developed an ammonia evaporator for thermal management systems aboard Freedom. The principal investigator for Creare Inc., formed Mikros Technologies Inc. to commercialize the work. Mikros Technologies then developed an advanced form of micro-electrical discharge machining (micro-EDM) to make tiny holes in the ammonia evaporator. Mikros Technologies has had great success applying this method to the fabrication of micro-nozzle array systems for industrial ink jet printing systems. The company is currently the world leader in fabrication of stainless steel micro-nozzles for this market, and in 2001 the company was awarded two SBIR research contracts from Goddard Space Flight Center to advance micro-fabrication and high-performance thermal management technologies.

2007-01-01

414

Flexible Metal-Fabric Radiators  

NASA Technical Reports Server (NTRS)

Flexible metal-fabric radiators have been considered as alternative means of dissipating excess heat from spacecraft and space suits. The radiators also may be useful in such special terrestrial applications as rejecting heat from space-suit-like protective suits worn in hot work environments. In addition to flexibility and consequent ease of deployment and installation on objects of varying sizes and shapes, the main advantages of these radiators over conventional rigid radiators are that they weigh less and occupy less volume for a given amount of cooling capacity. A radiator of this type includes conventional stainless-steel tubes carrying a coolant fluid. The main radiating component consists of a fabric of interwoven aluminum-foil strips bonded to the tubes by use of a proprietary process. The strip/tube bonds are strong and highly thermally conductive. Coolant is fed to and from the tubes via flexible stainless-steel manifolds designed to accommodate flexing of, and minimize bending forces on, the fabric. The manifolds are sized to minimize pressure drops and distribute the flow of coolant evenly to all the tubes. The tubes and manifolds are configured in two independent flow loops for operational flexibility and protective redundancy.

Cross, Cynthia; Nguyen, Hai D.; Ruemmele, Warren; Andish, Kambiz K.; McCalley, Sean

2005-01-01

415

Fabrication of plastic microfluidic components  

NASA Astrophysics Data System (ADS)

Plastic components have many advantages, including ease of fabrication, low cost, chemical inertness, lightweight, and disposability. We report on the fabrication of three plastics-based microfluidic components: a motherboard, a dialysis unit, and a metal sensor. Microchannels, headers, and interconnects were produced in thin sheets (>=50 microns) of polyimide, PMMA, polyethylene, and polycarbonate using a direct-write excimer laser micromachining system. Machined sheets were laminated by thermal and adhesive bonding to form leak-tight microfluidic components. The microfluidic motherboard borrowed the `functionality on a chip' concept from the electronics industry and was the heart of a complex microfluidic analytical device. The motherboard platform was designed to be tightly integrated and self-contained (i.e., liquid flows are all confined within machined microchannels), reducing the need for tubing with fluid distribution and connectivity. This concept greatly facilitated system integration and miniaturization. As fabricated, the motherboard consisted of three fluid reservoirs connected to micropumps by microchannels. The fluids could either be pumped independently or mixed in microchannels prior to being directed to exterior analytical components via outlet ports. The microdialysis device was intended to separate electrolytic solutes from low volume samples prior to mass spectrometric analysis. The device consisted of a dialysis membrane laminated between opposed serpentine microchannels containing the sample fluid and a buffer solution. The laminated metal sensor consisted of fluid reservoirs, micro-flow channels, micropumps, mixing channels, reaction channels, and detector circuitry.

Martin, Peter M.; Matson, Dean W.; Bennett, Wendy D.; Hammerstrom, D. J.

1998-09-01

416

Synthesis, Characterization, and Paclitaxel Release from a Biodegradable, Elastomeric, Poly(ester urethane)urea Bearing Phosphorylcholine Groups for Reduced Thrombogenicity  

PubMed Central

Biodegradable polymers with high elasticity, low thrombogenicity, and drug loading capacity continue to be pursued for vascular engineering applications, including vascular grafts and stents. A biodegradable elastomeric polyurethane was designed as a candidate material for use as a drug-eluting stent coating, such that it was nonthrombogenic and could provide antiproliferative drug release to inhibit smooth muscle cell proliferation. A phosphorylcholine containing poly(ester urethane) urea (PEUU-PC) was synthesized by grafting aminated phosphorylcholine onto backbone carboxyl groups of a polyurethane (PEUU-COOH) synthesized from a soft segment blend of polycaprolactone and dimethylolpropionic acid, a hard segment of diisocyanatobutane and a putrescine chain extender. Poly(ester urethane) urea (PEUU) from a soft segment of polycaprolactone alone was employed as a control material. All of the synthesized polyurethanes showed high distensibility (>600%) and tensile strengths in the 20–35 MPa range. PEUUPC experienced greater degradation than PEUU or PEUU-COOH in either a saline or lipase enzyme solution. PEUU-PC also exhibited markedly inhibited ovine blood platelet deposition compared with PEUU-COOH and PEUU. Paclitaxel loaded in all of the polymers during solvent casting continued to release for 5 d after a burst release in a 10% ethanol/PBS solution, which was utilized to increase the solubility of the releasate. Rat smooth muscle cell proliferation was significantly inhibited in 1 wk cell culture when releasate from the paclitaxel-loaded films was present. Based on these results, the synthesized PEUU-PC has promising functionality for use as a nonthrombogenic, drug eluting coating on metallic vascular stents and grafts. PMID:23035885

Hong, Yi; Ye, Sang-Ho; Pelinescu, Anca L.; Wagner, William R.

2013-01-01

417

Effects of Macroporous Resin Size on Candida antarctica Lipase B Adsorption, Fraction of Active Molecules, and Catalytic Activity for Polyester Synthesis  

SciTech Connect

Methyl methacrylate resins with identical average pore diameter (250 {angstrom}) and surface area (500 m{sup 2}/g) but with varied particle size (35 to 560-710 {mu}m) were employed to study how immobilization resin particle size influences Candida antarctica Lipase B (CALB) loading, fraction of active sites, and catalytic properties for polyester synthesis. CALB adsorbed more rapidly on smaller beads. Saturation occurred in less than 30 s and 48 h for beads with diameters 35 and 560-710 {mu}m, respectively. Linearization of adsorption isotherm data by the Scatchard analysis showed for the 35 {mu}m resin that: (1) CALB loading at saturation was well below that required to form a monolayer and fully cover the support surface and (2) CALB has a high affinity for this resin surface. Infrared microspectroscopy showed that CALB forms protein loading fronts for resins with particle sizes 560-710 and 120 {mu}m. In contrast, CALB appears evenly distributed throughout 35 {mu}m resins. By titration with p-nitrophenyl n-hexyl phosphate (MNPHP), the fraction of active CALB molecules adsorbed onto resins was <50% which was not influenced by particle size. The fraction of active CALB molecules on the 35 {mu}m support increased from 30 to 43% as enzyme loading was increased from 0.9 to 5.7% (w/w) leading to increased activity for {epsilon}-caprolactone ({epsilon}-CL) ring-opening polymerization. At about 5% w/w CALB loading, by decreasing the immobilization support diameter from 560-710 to 120, 75, and 35 {mu}m, conversion of {epsilon}-CL % to polyester increased (20 to 36, 42, and 61%, respectively, at 80 min). Similar trends were observed for condensation polymerizations between 1,8-octanediol and adipic acid.

Chen,B.; Miller, E.; Miller, L.; Maikner, J.; Gross, R.

2007-01-01

418

Biaxial extension of knitted steel fibre fabrics  

NASA Astrophysics Data System (ADS)

In this paper knitted steel fibre fabrics will be tested in biaxial extension. An in-house developed biaxial extension machine is used to apply a variety of strain conditions, which allows investigating the coupling between the wale and course direction of the fabrics and the degree of anisotropy in the fabric. Prior to testing a pretension level, to compensate the slack nature of the fabric, is determined by using a laser-measuring device. The strain inside the fabric is measured using a CCD camera technique. The results show the non-linear behaviour of the fabric and the coupling between the wale and the course direction. This will lead to a test protocol that can be used to evaluate the biaxial response of different types of knitted fabrics.

Vanclooster, K.; Eshghyar, A.; Lomov, S. V.

2011-05-01

419

Fabrication techniques for very fast diffractive lenses  

NASA Technical Reports Server (NTRS)

Aspheric lenses with arbitrary phase functions can be fabricated on thin light weight substrates via the binary optics fabrication technique. However, it is difficult and costly to fabricate a fast lens (f/number less than 1) for use as the shorter wavelengths. The pitch of the masks and the alignment accuracy must be very fine. For a large lens, the space-bandwidth product of the element can also become impractically large. In this paper, two alternate approaches for the fabrication of fast aspheric diffractive lenses are described. The first approach fabricates the diffractive lens interferometrically, utilizing a spherical wavefront to provide the optical power of the lens and a computer generated hologram to create the aspheric components. The second approach fabricates the aspheric diffractive lens in the form if a higher order kinoform which trades groove profile fidelity for coarser feature size. The design and implementation issues for these two fabrication techniques are discussed.

Tai, Anthony M.; Marron, Joseph C.

1993-01-01

420

Nanochannels' fabrication using Kirkendall effect  

NASA Astrophysics Data System (ADS)

Evidences of nanochannel formation based on Kirkendall effect have been previously reported for oxide nanowires covered with a thin alumina shell layer. Here we will investigate the nanochannel formation on an in situ pulsed laser deposition (PLD) fabricated structure of iron oxide shell layer over ZnO and MgO nanowire core and will compare with the alumina shell layer results. In all (four) cases a chemical reaction takes place on the interface producing a spinel buffer layer. Nanochannel formation process could be understood based on material diffusion coefficients through the spinel buffer layer but shell layer crystal structure seems to play a significant role.

Marcu, Aurelian; Yanagida, Takeshi; Kawai, Tomaji

2010-06-01

421

Fully biobased and supertough polylactide-based thermoplastic vulcanizates fabricated by peroxide-induced dynamic vulcanization and interfacial compatibilization.  

PubMed

A fully biobased and supertough thermoplastic vulcanizate (TPV) consisting of polylactide (PLA) and a biobased vulcanized unsaturated aliphatic polyester elastomer (UPE) was fabricated via peroxide-induced dynamic vulcanization. Interfacial compatibilization between PLA and UPE took place during dynamic vulcanization, which was confirmed by gel measurement and NMR analysis. After vulcanization, the TPV exhibited a quasi cocontinuous morphology with vulcanized UPE compactly dispersed in PLA matrix, which was different from the pristine PLA/UPE blend, exhibiting typically phase-separated morphology with unvulcanized UPE droplets discretely dispersed in matrix. The TPV showed significantly improved tensile and impact toughness with values up to about 99.3 MJ/m(3) and 586.6 J/m, respectively, compared to those of 3.2 MJ/m(3) and 16.8 J/m for neat PLA, respectively. The toughening mechanisms under tensile and impact tests were investigated and deduced as massive shear yielding of the PLA matrix triggered by internal cavitation of VUPE. The fully biobased supertough PLA vulcanizate could serve as a promising alternative to traditional commodity plastics. PMID:25287757

Liu, Guang-Chen; He, Yi-Song; Zeng, Jian-Bing; Li, Qiu-Tong; Wang, Yu-Zhong

2014-11-10

422

Sintered silicon nitrode recuperator fabrication  

NASA Technical Reports Server (NTRS)

The preliminary design and a demonstration of the feasibility of fabricating submodules of an automotive Stirling engine recuperator for waste heat recovery at 370 C are described. Sinterable silicon nitride (Sialon) tubing and plates were fabricated by extrusion and hydrostatic pressing, respectively, suitable for demonstrating a potential method of constructing ceramic recuperator-type heat exchangers. These components were fired in nitrogen atmosphere to 1800 C without significant scale formation so that they can be used in the as-fired condition. A refractory glass composition (Al2O3 x 4.5 CaO.MgO x 11SiO2) was used to join and seal component parts by a brazing technique which formed strong recuperator submodules capable of withstanding repeated thermal cycling to 1370 C. The corrosion resistance of these materials to Na2SO4 + NaCl carbon mixtures was also assessed in atmospheres of air, hydrogen and CO2-N2-H2O mixtures at both 870 C and 1370 C for times to 1000 hours. No significant reaction was observed under any of these test conditions.

Gatti, A.; Chiu, W. S.; Mccreight, L. R.

1980-01-01

423

Polymer micromold and fabrication process  

DOEpatents

A mold assembly with micro-sized features in which the hollow portion thereof is fabricated from a sacrificial mandrel which is surface treated and then coated to form an outer shell. The sacrificial mandrel is then selectively etched away leaving the outer shell as the final product. The sacrificial mandrel is fabricated by a precision lathe, for example, so that when removed by etching the inner or hollow area has diameters as small as 10's of micros (.mu.m). Varying the inside diameter contours of the mold can be accomplished with specified ramping slopes formed on the outer surface of the sacrificial mandrel, with the inside or hollow section being, for example, 275 .mu.m in length up to 150 .mu.m in diameter within a 6 mm outside diameter (o.d.) mold assembly. The mold assembly itself can serve as a micronozzle or microneedle, and plastic parts, such as microballoons for angioplasty, polymer microparts, and microactuators, etc., may be formed within the mold assembly.

Lee, Abraham P. (1428 Whitecliff Way, Walnut Creek, CA 94596); Northrup, M. Allen (923 Creston Rd., Berkeley, CA 94708); Ahre, Paul E. (1299 Gonzaga Ct., Livermore, CA 94550); Dupuy, Peter C. (1736 Waldo Ct., Modesto, CA 95358)

1997-01-01

424

Polymer micromold and fabrication process  

DOEpatents

A mold assembly is disclosed with micro-sized features in which the hollow portion thereof is fabricated from a sacrificial mandrel which is surface treated and then coated to form an outer shell. The sacrificial mandrel is then selectively etched away leaving the outer shell as the final product. The sacrificial mandrel is fabricated by a precision lathe, for example, so that when removed by etching the inner or hollow area has diameters as small as 10`s of micros ({micro}m). Varying the inside diameter contours of the mold can be accomplished with specified ramping slopes formed on the outer surface of the sacrificial mandrel, with the inside or hollow section being, for example, 275 {micro}m in length up to 150 {micro}m in diameter within a 6 mm outside diameter (o.d.) mold assembly. The mold assembly itself can serve as a micronozzle or microneedle, and plastic parts, such as microballoons for angioplasty, polymer microparts, and microactuators, etc., may be formed within the mold assembly. 6 figs.

Lee, A.P.; Northrup, M.A.; Ahre, P.E.; Dupuy, P.C.

1997-08-19

425

Galvanic etching for sensor fabrication  

NASA Astrophysics Data System (ADS)

This paper describes the application of a novel etch-stop technique, based on galvanic element formation, to the fabrication of micromechanical sensors. The theory of operation in tetramethyl ammonium hydroxide (TMAH) and hydrofluoric acid (HF) solutions is discussed, together with the main limitations. A number of devices are presented. These include a piezoresistive pressure sensor made with a galvanic etch stop in a 25% TMAH solution at 80 °C and the contactless fabrication in similar solutions of a vibration sensor based on free-standing crystalline silicon beams. The thickness definition and uniformity were found to be poorer with the cantilever than with the membrane type sensors. Oxygen in the solution was used to provide the cell current, which was therefore rather low. This resulted in a low package density of the sensor elements on the wafer. Free-standing thick polysilicon structures were also formed with a galvanic etch-stop technique in HF solutions. The selectivity of this process, and the thickness definition and uniformity were good. In these solutions, the cell current could be easily increased by adding other strong oxidizing agents, such as hydrogen peroxide. Therefore, high package densities could be achieved in these solutions.

Ashruf, C. M. A.; French, P. J.; Sarro, P. M.; Kazinczi, R.; Xia, X. H.; Kelly, J. J.

2000-12-01

426

Woven angle ply fabric and apparatus and method for producing such fabrics  

NASA Astrophysics Data System (ADS)

Planar or multilayer structural preforms are made having yarns extending in a bias direction of the preform. Angularly directed yarns can be inserted in planar and multilayer fabrics to increase shear strength of structural preforms made from the fabrics. In multilayer fabrics, the angle yarns can extend between layers to provide through-the-thickness reinforcement. Fabrics are formed by carrying yarns transversely across the fabric as the fabric advances. Fill yarns may be inserted by an insertion technique employing a pneumatic beating element. Angle yarn feeding arrangements are made readily removable to provide for the use of other weaving assemblies.

Farley, Gary L.

1991-09-01

427

Electrostatically self-assembled biodegradable microparticles from pseudoproteins and polysaccharide: fabrication, characterization, and biological properties.  

PubMed

Electrostatically self-assembling hybrid microparticles derived from novel cationic unsaturated arginine-based poly(ester amide) polymers (UArg-PEA) and anionic hyaluronic acid (HA) were fabricated into sub-micron-sized particles in aqueous medium with subsequent UV crosslinking treatment to stabilize the structure. These hybrid microparticles were characterized for size, charge, viscosity, chemical structure, morphology, and biological properties. Depending on the feed ratio of cationic UArg-PEA to anionic HA, the crosslinked microparticles formed spherical structures of 0.772-22.08 ?m in diameter, whereas the uncrosslinked microparticles formed a core with an outer petal-like structure of 2.49-15 ?m in diameter. It was discovered that the morphological structure of the self-assembled microparticles had a profound influence on their biological properties. At a 1:1 feed ratio of UArg-PEA to HA, the uncrosslinked microparticles showed no cytotoxicity toward NIH 3T3 fibroblasts at concentrations up to 20 ?g/mL, and the crosslinked particles exhibited no cytotoxicity at concentrations up to 10 ?g/mL. The UArg-PEA/HA hybrid microparticles exhibited a significantly lower macrophage-induced proinflammatory response (via TNF-?) than that from a pure hyaluronic acid control while retaining the beneficial anti-inflammatory IL-10 production by HA. The UArg-PEA/HA microparticles also stimulated size-dependent induction of arginase activity. Therefore, self-assembling these two types of biomaterials in a favorable nontoxic aqueous environment, having complementary biological properties like those of the currently reported UArg-PEA/HA hybrid microparticles, may provide a new class of biomaterials to improve the overall tissue microenvironment for promoting wound healing. PMID:25531946

Potuck, Alicia N; Weed, Beth L; Leifer, Cynthia A; Chu, C C

2015-02-01

428

Fabrication of superhydrophobic cotton fabrics by silica hydrosol and hydrophobization  

NASA Astrophysics Data System (ADS)

Superhydrophobic cotton fabrics were prepared by the incorporation of silica nanoparticles and subsequent hydrophobization with hexadecyltrimethoxysilane (HDTMS). The silica nanoparticles were synthesized via sol-gel reaction with methyl trimethoxy silane (MTMS) as the precursor in the presence of the base catalyst and surfactant in aqueous solution. As for the resulting products, characterization by particle size analyzer, scanning electron microscopy (SEM), scanning probe microscopy (SPM), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA) were performed respectively. The size of SiO2 nanoparticles can be controlled by adjusting the catalyst and surfactant concentrations. The wettability of cotton textiles was evaluated by the water contact angle (WCA) and water shedding angle (WSA) measurements. The results showed that the treated cotton sample displayed remarkable water repellency with a WCA of 151.9° for a 5 ?L water droplet and a WSA of 13° for a 15 ?L water droplet.

Xu, Lihui; Zhuang, Wei; Xu, Bi; Cai, Zaisheng

2011-04-01

429

Fabrication of Flexible Piezoelectric PZT/Fabric Composite  

PubMed Central

Flexible piezoelectric PZT/fabric composite material is pliable and tough in nature which is in a lack of traditional PZT patches. It has great application prospect in improving the sensitivity of sensor/actuator made by piezoelectric materials especially when they are used for curved surfaces or complicated conditions. In this paper, glass fiber cloth was adopted as carrier to grow PZT piezoelectric crystal particles by hydrothermal method, and the optimum conditions were studied. The results showed that the soft glass fiber cloth was an ideal kind of carrier. A large number of cubic-shaped PZT nanocrystallines grew firmly in the carrier with a dense and uniform distribution. The best hydrothermal condition was found to be pH 13, reaction time 24?h, and reaction temperature 200°C. PMID:24348194

Chen, Caifeng; Hong, Daiwei; Wang, Andong; Ni, Chaoying

2013-01-01

430

Fabrication of Large YBCO Superconducting Disks  

NASA Technical Reports Server (NTRS)

We have undertaken fabrication of large bulk items to develop a repeatable process and to provide test articles in laboratory experiments investigating reported coupling of electromagnetic fields with the local gravity field in the presence of rotating superconducting disks. A successful process was developed which resulted in fabrication of 30 cm diameter annular disks. The disks were fabricated of the superconductor YBa2Cu3O(7-x). Various material parameters of the disks were measured.

Koczor, Ronald J.; Noever, David A.; Robertson, Glen A.

1999-01-01

431

Dissipation of energy by bulletproof aramid fabric  

Microsoft Academic Search

The bullet resistance of laminates comprised of several layers of aramid Armos fabric has been studied. The high bullet resistance\\u000a of the fabric is caused by the pulling-out of yarns impacted by the bullet. The pull-out zone is cross-shaped, the centre\\u000a being the impact point. The length and the width of the pull-out zone was determined for each fabric layer.

S. BAZHENOV

1997-01-01

432

Update On Monolithic Fuel Fabrication Development  

SciTech Connect

Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Advancements have been made in the production of U-Mo foil including full sized foils. Progress has also been made in the friction stir welding and transient liquid phase bonding fabrication processes resulting in better bonding, more stable processes and the ability to fabricate larger fuel plates.

C. R Clark; J. M. Wight; G. C. Knighton; G. A. Moore; J. F. Jue

2005-11-01

433

Nano-fabricated size exclusion chromatograph  

NASA Technical Reports Server (NTRS)

This paper describes the development of a nano-fabricated size exclusion chromatograph (nSEC) based on the principle that molecules traveling through amicrocolumn containing nano-fabricated features will have characteristic elution times that directly correlate to molecular weight. Compared to conventional size exclusion chromatography, the nSEC offers greater control over the size exclusion process; mass fabrication; integration of the separation column with associated valves, pumps, and detectors; and dramatic reductions in instrument mass and power requirements.

Svehla, D.; Feldman, S.; Feldman, J.; Grunthaner, F.; Shakkottai, P.; Castillo, L. del; White, V.

2002-01-01

434

Fast Freeform Fabrication Methods and Processes  

Microsoft Academic Search

Fast freeform fabrication, also called rapid prototyping, is the automatic manufacturing techniques using slicing and additive\\u000a processes. The first techniques for fast freeform fabrication became available in the late 1980s and were used to produce\\u000a models and prototype parts. With the fast freeform fabrication method, the machine reads in data from a CAD drawing, slicing\\u000a the CAD model into a

Wanlong Wang; Henry W. Stoll; James G. Conley

435

Melt-spun shaped fibers with enhanced surface effects: fiber fabrication, characterization and application to woven scaffolds.  

PubMed

Scaffolds with a high surface-area-to-volume ratio (SA:V) are advantageous with regard to the attachment and proliferation of cells in the field of tissue engineering. This paper reports on the development of novel melt-spun fibers with a high SA:V, which enhanced the surface effects of a fiber-based scaffold while maintaining its mechanical strength. The cross-section of the fibers was altered to a non-circular shape, producing a higher SA:V for a similar cross-sectional area. To obtain fibers with non-circular cross-sectional shape, or shaped fibers, three different types of metal spinnerets were fabricated for the melt-spinning process, each with circular, triangular or cruciform capillaries, using deep X-ray lithography followed by nickel electroforming. Using these spinnerets, circular and shaped fibers were manufactured with biodegradable polyester, polycaprolactone. The SA:V increase in the shaped fibers was experimentally investigated under different processing conditions. Tensile tests on the fibers and indentation tests on the woven fiber scaffolds were performed. The tested fibers and scaffolds exhibited similar mechanical characteristics, due to the similar cross-sectional area of the fibers. The degradation of the shaped fibers was notably faster than that of circular fibers, because of the enlarged surface area of the shaped fibers. The woven scaffolds composed of the shaped fibers significantly increased the proliferation of human osteosarcoma MG63 cells. This approach to increase the SA:V in shaped fibers could be useful for the fabrication of programmable, biodegradable fiber-based scaffolds in tissue engineering. PMID:23669620

Park, S J; Lee, B-K; Na, M H; Kim, D S

2013-08-01

436

Fabrication of Extremely Lightweight Mirrors  

NASA Technical Reports Server (NTRS)

Further progress in astronomy requires large.(approx. 10m class) space telescopes in all wavelength bands, from IR to X-rays. The enabling of this progress requires optical fabrication technologies that not only can make mirrors that are orders of magnitude less massive than the present ones, but also orders of magnitude less expensive. In the past five years, we have been developing lightweight X-ray mirrors to meet mission requirements of the Constellation-X, which is NASA s next major X-ray observatory scheduled for launch some time in the next decade. In this talk, I will describe in detail a glass forming, or slumping, technique that allows a high-fidelity copying of a mandrel s figure while preserving the microroughness of the float glass surface. In particular, I will address the possibility of applying this technique to making extremely large optical telescopes.

Zhang, William W.

2006-01-01

437

Method of fabricating composite structures  

NASA Technical Reports Server (NTRS)

A method of fabricating structures formed from composite materials by positioning the structure about a high coefficient of thermal expansion material, wrapping a graphite fiber overwrap about the structure, and thereafter heating the assembly to expand the high coefficient of thermal expansion material to forcibly compress the composite structure against the restraint provided by the graphite overwrap. The high coefficient of thermal expansion material is disposed about a mandrel with a release system therebetween, and with a release system between the material having the high coefficient of thermal expansion and the composite material, and between the graphite fibers and the composite structure. The heating may occur by inducing heat into the assembly by a magnetic field created by coils disposed about the assembly through which alternating current flows. The method permits structures to be formed without the use of an autoclave.

Sigur, W. A. (inventor)

1990-01-01

438

Glass Nanofiber Fabrication and Devices  

NASA Astrophysics Data System (ADS)

We have integrated electric field assisted spinning (electrospinning) of polymeric materials with photolithography for the fabrication of glass nanostructures. We incorporated spin on glass (SOG) dielectric coating with poly-vinyl-pyrrolidone (PVP) and spun this solution over trenches etched in silicon. A calcination eliminated the PVP polymer from these fibers, while cross-linking the SOG, leaving silica glass fibers with diameters as small as 70 nm. We demonstrated the operation of these fibers as nanomechanical oscillators. We also spun heat depolymerizable polycarbonate (HDPC) fibers over silicon trenches. These fibers were coated with glass by chemical vapor deposition or sputtering, followed by thermal elimination of the polymer core. This yielded suspended glass channels of elliptical cross sections, with inner major and minor axes as small as 75 and 50 nm. These nanochannels offer a low background option for doing fluorescence detection, as demonstrated by single molecule detection, using a confocal microscope, of cellulase enzymes in these channels.

Verbridge, Scott; Edel, Joshua

2005-03-01

439

Surface Modification for Microreactor Fabrication  

PubMed Central

In this paper, methods of surface modification of different supports, i.e. glass and polymeric beads for enzyme immobilisation are described. The developed method of enzyme immobilisation is based on Schiff's base formation between the amino groups on the enzyme surface and the aldehyde groups on the chemically modified surface of the supports. The surface of silicon modified by APTS and GOPS with immobilised enzyme was characterised by atomic force microscopy (AFM), time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and infrared spectroscopy (FTIR). The supports with immobilised enzyme (urease) were also tested in combination with microreactors fabricated in silicon and Perspex, operating in a flow-through system. For microreactors filled with urease immobilised on glass beads (Sigma) and on polymeric beads (PAN), a very high and stable signal (pH change) was obtained. The developed method of urease immobilisation can be stated to be very effective.

Pijanowska, Dorota G.; Remiszewska, El?bieta; Pederzolli, Cecilia; Lunelli, Lorenzo; Vendano, Michele; Canteri, Roberto; Dudzi?ski, Konrad; Kruk, Jerzy; Torbicz, Wladyslaw

2006-01-01

440

Layered structure and Xe sorption and diffusion properties of low-density liquid-crystalline polyesters with n-alkyl side chains  

NASA Astrophysics Data System (ADS)

Four low-density liquid-crystalline polyesters with n-alkyl side chains, B-C n ( n is a carbon number of n-alkyl group), were synthesized from the 1,4-di-( n-alkyl ester) of 1,2,4,5-benzenetetracarboxylic acid and 4,4'-biphenol, to clarify the effect of side chain length on higher ordered structure in the solid state and gas sorption and diffusion properties of these polyesters. All the B-C n ( n=6, 10, 14, 18) samples behaved as a thermotropic liquid crystal and formed a layered structure composed of alternating rigid aromatic main chain layers and flexible n-alkyl side chain layers. In the crystal phase, the distance between the rigid aromatic main chain layers, namely the layer spacing, linearly increased with n, indicating that the conformational feature of n-alkyl side chains was trans-rich. This finding was supported from the 13C NMR chemical shift values of methylene carbons in B-C14 and B-C18. Xe sorption of B-C n was restricted to the side chain layer, which is almost a liquid-like environment, and these sorption isotherms obeyed Henry's law. The density of side chain layers was estimated from experimental values of layer spacing and density, under some speculate assumptions, but that determined individually by 129Xe NMR spectroscopy was coincidence. The estimated density of side chain layers became higher with increasing n, as well as n-alkane liquid, and closed to that of the polyethylene in rubbery state. Xe solubility coefficient corrected with the estimated side chain layer's density decreased with increasing n. On the other hand, the diffusion coefficient of Xe in B-C n increased with n, and this was supported from the NMR spectral width of the 129Xe in B-C n. These results also indicate that the main chain layers of B-C n were very dense and could not sorb Xe.

Yoshimizu, Hiroaki; Tsukahara, Mitsuhiro; Suzuki, Tomoyuki; Toida, Jiro; Ando, Aisuke; Watanabe, Junji; Tsujita, Yoshiharu

2005-04-01

441

Enzymatically and Reductively Degradable ?-Amino Acid-Based Poly(ester amide)s: Synthesis, Cell Compatibility, and Intracellular Anticancer Drug Delivery.  

PubMed

A novel and versatile family of enzymatically and reductively degradable ?-amino acid-based poly(ester amide)s (SS-PEAs) were developed from solution polycondensation of disulfide-containing di-p-toluenesulfonic acid salts of bis-l-phenylalanine diesters (SS-Phe-2TsOH) with di-p-nitrophenyl adipate (NA) in N,N-dimethylformamide (DMF). SS-PEAs with Mn ranging from 16.6 to 23.6 kg/mol were obtained, depending on NA/SS-Phe-2TsOH molar ratios. The chemical structures of SS-PEAs were confirmed by (1)H NMR and FTIR spectra. Thermal analyses showed that the obtained SS-PEAs were amorphous with a glass transition temperature (Tg) in the range of 35.2-39.5 °C. The in vitro degradation studies of SS-PEA films revealed that SS-PEAs underwent surface erosion in the presence of 0.1 mg/mL ?-chymotrypsin and bulk degradation under a reductive environment containing 10 mM dithiothreitol (DTT). The preliminary cell culture studies displayed that SS-PEA films could well support adhesion and proliferation of L929 fibroblast cells, indicating that SS-PEAs have excellent cell compatibility. The nanoparticles prepared from SS-PEA with PVA as a surfactant had an average size of 167 nm in phosphate buffer (PB, 10 mM, pH 7.4). SS-PEA nanoparticles while stable under physiological environment undergo rapid disintegration under an enzymatic or reductive condition. The in vitro drug release studies showed that DOX release was accelerated in the presence of 0.1 mg/mL ?-chymotrypsin or 10 mM DTT. Confocal microscopy observation displayed that SS-PEA nanoparticles effectively transported DOX into both drug-sensitive and -resistant MCF-7 cells. MTT assays revealed that DOX-loaded SS-PEA nanoparticles had a high antitumor activity approaching that of free DOX in drug-sensitive MCF-7 cells, while more than 10 times higher than free DOX in drug-resistant MCF-7/ADR cells. These enzymatically and reductively degradable ?-amino acid-based poly(ester amide)s have provided an appealing platform for biomedical technology in particular controlled drug delivery applications. PMID:25555025

Sun, Huanli; Cheng, Ru; Deng, Chao; Meng, Fenghua; Dias, Aylvin A; Hendriks, Marc; Feijen, Jan; Zhong, Zhiyuan

2015-02-01

442

TOPICAL REVIEW: DNA nanowire fabrication  

NASA Astrophysics Data System (ADS)

Deoxyribonucleic acid (DNA) has been a key building block in nanotechnology since the earliest work on what is now called DNA-templated self-assembly (Alivisatos et al 1996 Nature 382 609; Mirkin et al 1996 Nature 382 607; Braun et al 1998 Nature 391 775). A range of different nanoparticles and nanoclusters have been assembled on single DNA molecules for a variety of purposes (Braun et al 1998 Nature 391 775; Richter et al 2001 Appl. Phys. Lett. 78 536; Park et al 2002 Science 295 1503; Mirkin 2000 Inorg. Chem. 39 2258; Keren et al 2003 Science 302 1380). Electrically conductive silver (Braun et al 1998 Nature 391 775) and palladium (Richter et al 2001 Appl. Phys. Lett. 78 536) nanowires, for example, have been fabricated by DNA templating for the development of interconnection of nanoelectric elements, and field effect transistors have been built by assembly of a single carbon nanotube and DNA-templated nanowires (Keren et al 2003 Science 302 1380). DNA is well suited for nanowire assembly because of its size, well organized structure, and exquisite molecular-recognition-ability-specific base pairing. This property has been used to detect nucleic acids (Park et al 2002 Science 295 1503) and anthrax (Mirkin 2000 Inorg. Chem. 39 2258) with high sensitivity and specificity. Molecular recognition can also be used to localize nanowires in electronics. Various methods, for example molecular combing, electrophoretic stretching, and hydrodynamic stretching, have been developed to orient DNA molecules on a solid support. This review focuses on methods used to manipulate and metallize DNA in nanowire fabrication. A novel approach based on a single-stranded DNA template and molecular recognition is also discussed.

Gu, Qun; Cheng, Chuanding; Gonela, Ravikanth; Suryanarayanan, Shivashankar; Anabathula, Sathish; Dai, Kun; Haynie, Donald T.

2006-01-01

443

Nanotube Fabrication byNanotube Fabrication by Anodic Aluminum Oxide,Anodic Aluminum Oxide,  

E-print Network

Nanotube Fabrication byNanotube Fabrication by Anodic Aluminum Oxide,Anodic Aluminum Oxide, Self-regulating phenomena in materials science: Self-assembly of nanopores during anodic oxidation of aluminum (AAO) Self combined anodic aluminum oxide (AAO) nanostructures with atomic layer deposition (ALD) to fabricate

Rubloff, Gary W.

444

FILTRATION PARAMETERS FOR DUST CLEANING FABRICS  

EPA Science Inventory

The report describes laboratory and pilot scale testing of bag filter fabrics. Filtration performance data and mathematical modeling parameters are given for four Polish fabrics tested with cement dust, coal dust, flyash, and talc. Conclusions include: (1) The process of clean ai...

445

Fabrication and characterization of isotropic magnetorheological elastomers  

Microsoft Academic Search

This paper presents a new method to fabricate isotropic magnetorheological (MR) elastomers under natural conditions. In the absence of a magnetic field, a variety of MR elastomer samples made of carbonyl iron particles, silicon rubber and silicone oil, were fabricated. Their dynamic viscoelastic properties were characterized by a measurement system developed by our group. Also, the microstructure of the samples

X. L. Gong; X. Z. Zhang; P. Q. Zhang

2005-01-01

446

Nano-fabricated size exclusion chromatograph  

NASA Technical Reports Server (NTRS)

This poster describes the development of a nano-fabricated size exclusion chromatograph (nSEC) based on the principle that molecules traveling through a microcolumn containing nano-fabricated features will have characteristics elution times that directly correlate to molecular weight.

Svehla, D.; Feldman, S.; Feldman, J.; Grunthaner, F.; Shakkottai, P.; dle Castillo, L.; White, V.

2002-01-01

447

Productive Nanosystems: The Physics of Molecular Fabrication  

ERIC Educational Resources Information Center

Fabrication techniques are the foundation of physical technology, and are thus of fundamental interest. Physical principles indicate that nanoscale systems will be able to fabricate a wide range of structures, operating with high productivity and precise molecular control. Advanced systems of this kind will require intermediate generations of…

Drexler, K. Eric

2005-01-01

448

Analysis and fabrication of patterned magnetorheological elastomers  

Microsoft Academic Search

This paper presents analysis, fabrication and characterization of patterned magnetorheological (MR) elastomers. By taking into account the local magnetic field in MREs and particle interaction magnetic energy, the magnetic-field-dependent mechanical properties of MREs with lattice and BCC structures were theoretically analyzed and numerically simulated. Soft magnetic particles were assembled in a polydimethylsiloxane (PDMS) matrix to fabricate new MR elastomers with

Xianzhou Zhang; Suili Peng; Weijia Wen; Weihua Li

2008-01-01

449

Cotton fabrics with single-faced superhydrophobicity.  

PubMed

This article reports on the fabrication of cotton fabrics with single-faced superhydrophobicity using a simple foam finishing process. Unlike most commonly reported superhydrophobic fabrics, the fabrics developed in this study exhibit asymmetric wettability on their two faces: one face showing superhydrophobic behavior (highly nonwetting or water-repellent characteristics) and the other face retaining the inherent hydrophilic nature of cotton. The superhydrophobic face exhibits a low contact angle hysteresis of ?(a)/?(r) = 151°/144° (?(a), advancing contact angle; ?(r), receding contact angle), which enables water drops to roll off the surface easily so as to endow the surface with well-known self-cleaning properties. The untreated hydrophilic face preserves its water-absorbing capability, resulting in 44% of the water-absorbing capacity compared to that of the original cotton samples with both sides untreated (hydrophilic). The single-faced superhydrophobic fabrics also retain moisture transmissibility that is as good as that of the original untreated cotton fabrics. They also show robust washing fastness with the chemical cross-linking process of hydrophobic fluoropolymer to fabric fibers. Fabric materials with such asymmetric or gradient wettability will be of great use in many applications such as unidirectional liquid transporting, moisture management, microfluidic systems, desalination of seawater, flow management in fuel cells, and water/oil separation. PMID:23186211

Liu, Yuyang; Xin, J H; Choi, Chang-Hwan

2012-12-18

450

Fabricating Structural Stiffeners By Superplastic Forming  

NASA Technical Reports Server (NTRS)

Superplastic forming (SPF) of aluminum alloys effective technique for making strong, lightweight structural components conforming to close dimensional tolerances. Technique applied in experimental fabrication of prototypes of stiffening ribs for cylindrical tanks. When making structural panel, stiffening ribs spot-welded to metal skin. Use of discrete eliminates machining waste, and use of SPF. Cost of fabrication reduced.

Bales, Thomas T.; Shinn, Joseph M., Jr.; Hales, Stephen J.; James, William F.

1994-01-01

451

Designs and fabrications of integrated optical isolators  

Microsoft Academic Search

Integrated optical circuits are low cost, compact, and highly functional devices that are very attractive in fiber telecommunication systems and other applications. Integrated optical isolators have been designed and even fabricated for several years although fabrication processes have made it difficult to commercialize such devices. The most conventional type of an integrated optical isolator, called a hybrid integrated isolator, has

Junichiro Fujita

2000-01-01

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