Note: This page contains sample records for the topic thermoplastic puncture-healing polymers from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Bonding of thermoplastic polymer microfluidics  

Microsoft Academic Search

Thermoplastics are highly attractive substrate materials for microfluidic systems, with important benefits in the development\\u000a of low cost disposable devices for a host of bioanalytical applications. While significant research activity has been directed\\u000a towards the formation of microfluidic components in a wide range of thermoplastics, sealing of these components is required\\u000a for the formation of enclosed microchannels and other microfluidic

Chia-Wen Tsao; Don L. DeVoe

2009-01-01

2

Method of forming a foamed thermoplastic polymer  

DOEpatents

A solid thermoplastic polymer is immersed in an immersant solution comprising a compatible carrier solvent and an infusant solution containing an incompatible liquid blowing agent for a time sufficient for the immersant solution to infuse into the polymer. The carrier solvent is then selectively extracted, preferably by a solvent exchange process in which the immersant solution is gradually diluted with and replaced by the infusant solution, so as to selectively leave behind the infustant solution permanently entrapped in the polymer. The polymer is then heated to volatilize the blowing agent and expand the polymer into a foamed state.

Duchane, D.V.; Cash, D.L.

1984-11-21

3

Dynamically cured thermoplastic olefin polymers  

SciTech Connect

A thermoplastic composition is described comprising a polyolefin resin, a first rubber component selected from the group consisting of polyisobutylene, and ethylene propylene copolymer (EPM) and EPDM and a second rubber component selected from the group consisting of halogenated butyl rubber and polychoroprene, the second rubber component being cured utilizing a curative other than a peroxide, which is a vulcanizing agent for the second rubber but not for the first rubber, the second rubber being cured to a fully vulcanized state by dynamic vulcanization in the presence of the polyolefin resin and first rubber compound.

Hazelton, D.R.; Puydak, R.C.; Booth, D.A.

1986-08-19

4

Improved adhesion for thermoplastic polymers using oxyfluorination  

NASA Astrophysics Data System (ADS)

Industrial applications of thermoplastic polymers are often limited by their poor adhesion properties. In this work the effect of surface oxyfluorination on the adhesion properties was investigated for polyethylene (PE), polyoxymethylene (POM), polybutylene terephthalate (PBT) and polyamide 6 (PA6). The adhesive joint strength was quantified using lap-shear tests. These results were correlated with the changes in the chemical composition of the surface, determined by X-ray photoelectron spectroscopy (XPS), in the surface free energy, measured by the contact angle method, and in the topography, using white-light confocal microscopy. The adhesive strength is strongly improved for all four polymers, but the degree of this increase depends on the polymer type. The surface free energy shows a similar trend for all four polymers. A high surface free energy exceeding 50 mN/m was observed after oxy-fluorination, whereby the polar component was strongly predominant. Surface topography measurements show no significant increase of the surface roughness. So the effect of oxyfluorination results primarily in increased wettability and polarity, due to changes of the chemical composition of the surface. XPS measurements confirm the integration of fluorine and oxygen groups in the polymer chain, which correlates with the increased polarity.

Achereiner, F.; Münstedt, H.; Zeiler, T.

2008-03-01

5

Microscale Patterning of Thermoplastic Polymer Surfaces by Selective Solvent Swelling  

PubMed Central

A new method for the fabrication of microscale features in thermoplastic substrates is presented. Unlike traditional thermoplastic microfabrication techniques, in which bulk polymer is displaced from the substrate by machining or embossing, a unique process termed orogenic microfabrication has been developed in which selected regions of a thermoplastic surface are raised from the substrate by an irreversible solvent swelling mechanism. The orogenic technique allows thermoplastic surfaces to be patterned using a variety of masking methods, resulting in three-dimensional features that would be difficult to achieve through traditional microfabrication methods. Using cyclic olefin copolymer as a model thermoplastic material, several variations of this process are described to realize growth heights ranging from several nanometers to tens of microns, with patterning techniques include direct photoresist masking, patterned UV/ozone surface passivation, elastomeric stamping, and noncontact spotting. Orogenic microfabrication is also demonstrated by direct inkjet printing as a facile photolithography-free masking method for rapid desktop thermoplastic microfabrication.

Rahmanian, Omid; Chen, Chien-Fu; DeVoe, Don L.

2012-01-01

6

Pyrolysis-Gas Chromatography/Mass Spectrometry of Thermoplastic Polymers.  

National Technical Information Service (NTIS)

Thermal degradation mechanisms of ten thermoplastic polymers have been investigated using pyrolysis-gas chromatography with mass spectrometric and flame ionization detection. The results indicate that an unknown plastic can be identified on the basis of i...

J. A. Hiltz M. C. Bissonnette

1988-01-01

7

Photoinitiated grafting of porous polymer monoliths and thermoplastic polymers for microfluidic devices  

DOEpatents

A microfluidic device preferably made of a thermoplastic polymer that includes a channel or a multiplicity of channels whose surfaces are modified by photografting. The device further includes a porous polymer monolith prepared via UV initiated polymerization within the channel, and functionalization of the pore surface of the monolith using photografting. Processes for making such surface modifications of thermoplastic polymers and porous polymer monoliths are set forth.

Frechet, Jean M. J. (Oakland, CA); Svec, Frantisek (Alameda, CA); Rohr, Thomas (Leiden, NL)

2008-10-07

8

Analysis of thermoplastic polyimide + polymer liquid crystal blends  

Microsoft Academic Search

Thermoplastic polyimides (TPIs) exhibit high glass transition temperatures (Tsbgs), which make them useful in high performance applications. Amorphous and semicrystalline TPIs show sub-Tsbg relaxations, which can aid in improving strength characteristics through energy absorption. The alpha relaxation of both types of TPIs indicates a cooperative nature. The semicrystalline TPI shows thermo-irreversible cold crystallization phenomenon. The polymer liquid crystal (PLC) used

Bhaskar Gopalanarayanan

1998-01-01

9

TOPICAL REVIEW: Review on micro molding of thermoplastic polymers  

Microsoft Academic Search

Molding of micro components from thermoplastic polymers has become a routinely used industrial production process. This paper describes both the more than 30-year-old history and the present state of development and applications. Hot embossing, injection molding, reaction injection molding, injection compression molding, thermoforming, and various types of tool fabrication are introduced and their advantages and drawbacks are discussed. In addition,

M. Heckele; W. K. Schomburg

2004-01-01

10

Thermoplastic polymers surfaces for Dip-Pen Nanolithography of oligonucleotides  

NASA Astrophysics Data System (ADS)

Different thermoplastic polymers were spin-coated to prepare smooth surfaces for the direct deposition of end-group modified oligonucleotides by Dip-Pen Nanolithography. A study of the diffusion process was done in order to investigate the dependence of calibration coefficient and quality of deposited features on environmental parameters (temperature, relative humidity) and ink's molecular weight and functionality. The optimization of the process parameters led to the realization of high quality and density nanoarrays on plastics.

Suriano, Raffaella; Biella, Serena; Cesura, Federico; Levi, Marinella; Turri, Stefano

2013-05-01

11

The use of thermoplastic elastomers as polymer processing aids in processing of linear low density polyethylene  

Microsoft Academic Search

Commercially available thermoplastic elastomers based on block copolymers of diisocyanates and polyols and based on silicones\\u000a have been reported by Kulikov et al. (2004 and 2006) to delay sharkskin in extrusion of Linear Low Density Polyethylene. In\\u000a this work thermoplastic elastomers have been used as polymer processing additives in blown film extrusion of Linear Low Density\\u000a Polyethylene. When a thermoplastic

M. Müller; O. Kulikov; K. Hornung; M. H. Wagner

2010-01-01

12

Analysis of ageing of amorphous thermoplastic polymers by PVT analysis  

NASA Astrophysics Data System (ADS)

The aim of this work is the analysis of ageing phenomenon occurring in amorphous thermoplastic polymers below their glass transition temperature by pressure-volume-temperature (PVT) analysis. The ageing behavior of different polymers as a function of the heating and cooling rates has been widespread studied. Also, different works in literature are aimed to study the effect of the applied pressure on the glass transition behavior. Another relevant aspect related to the glass transition behavior is related to the ageing effects, which can also be influenced by the applied pressure. This is a very relevant issue, since most of the polymers, during ageing, are subjected to mechanical loading. PVT analysis was used to study the ageing of amorphous PET copolymer (PETg) at different pressure levels. Specific volume-temperature curves measured during the cooling and the heating steps were used for calculating the relaxed specific volume, showing that ageing effects increase with increasing applied pressure. The evolution of the fictive temperature as a function of time was calculated from experimental data.

Greco, Antonio; Maffezzoli, Alfonso; Gennaro, Riccardo; Rizzo, Michele

2012-07-01

13

Process for Continuous Foam Extrusion of Thermoplastic Polymers Via Syntactic and Chemical Foaming Agents.  

National Technical Information Service (NTIS)

A process for producing an electrical insulative material. First there is produced a composition including a thermoplastic polymer resin selected from the group consisting of a polyethylene octene, a polyethylene hexene, a polyethylene heptene, a polyethy...

D. V. Beauregard J. A. Jones L. J. Trainer N. R. Schott S. A. Orroth

2003-01-01

14

Damage healing ability of a shape-memory-polymer-based particulate composite with small thermoplastic contents  

NASA Astrophysics Data System (ADS)

The purpose of this study is to investigate the potential of a shape-memory-polymer (SMP)-based particulate composite to heal structural-length scale damage with small thermoplastic additive contents through a close-then-heal (CTH) self-healing scheme that was introduced in a previous study (Li and Uppu 2010 Comput. Sci. Technol. 70 1419-27). The idea is to achieve reasonable healing efficiencies with minimal sacrifice in structural load capacity. By first closing cracks, the gap between two crack surfaces is narrowed and a lesser amount of thermoplastic particles is required to achieve healing. The particulate composite was fabricated by dispersing copolyester thermoplastic particles in a shape memory polymer matrix. It is found that, for small thermoplastic contents of less than 10%, the CTH scheme followed in this study heals structural-length scale damage in the SMP particulate composite to a meaningful extent and with less sacrifice of structural capacity.

Nji, Jones; Li, Guoqiang

2012-02-01

15

Deposition of a ceramic coating on a thermoplastic polymer by atmospheric plasma and laser cladding  

Microsoft Academic Search

Alumina powder was deposited on a thermoplastic polymer using an atmospheric plasma and laser (CO2, ?=10.6 ?m). The results have shown that a mechanical anchorage of the ceramic exists on the surface of the polymer, regardless of the technique used or different ceramic structures. In addition, the morphology of the poly(ethyleneterephthalate) changes during the treatments and the polymer crystallizes. Hence,

S. Ayrault; A. Chateauminois; J. P. Soulier; D. Tréheux; A. B. Vannes

1996-01-01

16

Clearweld laser transmission welding of thermoplastic polymers: light transmission and color considerations  

Microsoft Academic Search

The past three years has seen the evolution and maturation of Clearweld technology as a tool which is readily employable for the transmission laser welding of thermoplastic and some thermoset polymers using near infrared lasers and inks uniquely chosen and targeted to absorb the laser light at the intended laser weld joint in order to efficiently and rapidly effectuate the

Scott Hartley; Robert A. Sallavanti

2003-01-01

17

Review of potential processing techniques for the encapsulation of wastes in thermoplastic polymers  

SciTech Connect

Thermoplastic encapsulation has been extensively studied at Brookhaven National Laboratory`s (BNL) Environmental and Waste Technology Center (EWTC) as a waste encapsulation technology applicable to a wide range of waste types including radioactive, hazardous and mixed wastes. Encapsulation involves processing thermoplastic and waste materials into a waste form product by heating and mixing both materials into a homogeneous molten mixture. Cooling of the melt results in a solid monolithic waste form in which contaminants have been completely surrounded by a polymer matrix. Heating and mixing requirements for successful waste encapsulation can be met using proven technologies available in various types of commercial equipment. Processing techniques for thermoplastic materials, such as low density polyethylene (LDPE), are well established within the plastics industry. The majority of commercial polymer processing is accomplished using extruders, mixers or a combination of these technologies. Extruders and mixers are available in a broad range of designs and are used during the manufacture of consumer and commercial products as well as for compounding applications. Compounding which refers to mixing additives such as stabilizers and/or colorants with polymers, is analogous to thermoplastic encapsulation. Several processing technologies were investigated for their potential application in encapsulating residual sorbent waste in selected thermoplastic polymers, including single-screw extruders, twin-screw extruders, continuous mixers, batch mixers as well as other less conventional devices. Each was evaluated based on operational ease, quality control, waste handling capabilities as well as degree of waste pretreatment required. Based on literature review, this report provides a description of polymer processing technologies, a discussion of the merits and limitations of each and an evaluation of their applicability to the encapsulation of sorbent wastes.

Patel, B.R.; Lageraaen, P.R.; Kalb, P.D.

1995-08-01

18

Effect of Blending on the Structure of Thermoplastic Interpenetrating Polymer Networks  

Microsoft Academic Search

The infrared absorption spectra of thermoplastic interpenetrating polymer networks based on semicrystalline polyurethane (CPU) and a styrene\\/acrylic acid block?copolymer (S?b?AA(K), salt form) have been measured over the spectral range between 4000 and 600 cm in an attempt to study their structure. The analysis of the spectra of the individual polymers and CPU\\/S?b?AA(K) blends has shown the mutual influence of components on

O. Grigoryeva; O. Slisenko; E. Lebedev; A. Bartolotta; Giovanni Carini; Giuseppe Carini; G. DAngelo; G. Tripodo

2007-01-01

19

Computer Simulation for Laser Welding of Thermoplastic Polymers  

Microsoft Academic Search

This paper presents an analytical approach to thermal behaviors of laser welding of polymers. Laser polymers processing leads to various thermal, photophysical, and photochemical processes within the bulk and on the material surface. The understanding of these processes is beneficial to obtaining the high quality precision engineering of polymers. The Green's function of a multi-layer plate for the transient heat

Ching-Yen Ho; Moa-Yu Wen; Chung Ma

2010-01-01

20

Welding methods for joining thermoplastic polymers for the hermetic enclosure of medical devices.  

PubMed

New high performance polymers have been developed that challenge traditional encapsulation materials for permanent active medical implants. The gold standard for hermetic encapsulation for implants is a titanium enclosure which is sealed using laser welding. Polymers may be an alternative encapsulation material. Although many polymers are biocompatible, and permeability of polymers may be reduced to acceptable levels, the ability to create a hermetic join with an extended life remains the barrier to widespread acceptance of polymers for this application. This article provides an overview of the current techniques used for direct bonding of polymers, with a focus on thermoplastics. Thermal bonding methods are feasible, but some take too long and/or require two stage processing. Some methods are not suitable because of excessive heat load which may be delivered to sensitive components within the capsule. Laser welding is presented as the method of choice; however the establishment of suitable laser process parameters will require significant research. PMID:20570545

Amanat, Negin; James, Natalie L; McKenzie, David R

2010-06-08

21

Cold Spray Coating Deposition Mechanism on the Thermoplastic and Thermosetting Polymer Substrates  

NASA Astrophysics Data System (ADS)

Cold spraying is a successful and promising coating technique for many engineering applications due to its high-rate and high-dense coating development abilities. Nevertheless, their practical use in polymer substrate is still in the fledgling phase. There are very few articles about the cold spray coating on polymers; however, the interaction of metallic particle with the polymer substrate is poorly understood, and thus a thick coating has not successfully been developed on the polymer substrate. In order to rationalize as full as possible the entire behavior of the high velocity particle with the polymer substrate, we used thermoplastic and thermosetting polymer materials as substrates. The particle behaviors with the substrate were observed under various gas pressure and temperature, and with various particles feed rate. The result showed that the particle behaviors were unique with respect to the substrate. Also it was clearly understood that the metal particles not experienced any plastic deformation due to the soft nature of the polymer substrates. The particles attached to the thermoplastic substrate either through adhesive bonding and/or mechanical inter locking, whereas only pure localized fracture observed on the thermosetting substrate and thus no particles attached firmly on the substrate.

Ganesan, Amirthan; Yamada, Motohiro; Fukumoto, Masahiro

2013-08-01

22

Spall fracture characterization of thermosetting and thermoplastic polymer matrix composite plates  

Microsoft Academic Search

So-called spall fractures (through-the-thickness tensile impact fractures) in simple uniaxial strain were examined for typical glass fiber reinforced thermosetting and thermoplastic polymer composite plates. An exploding foil technique was used to accelerate thin flyer plates towards composite plates to generate spall fractures. For thermosetting polyester composites, different fiber surface treatments were applied to study the effects of interfacial strengths on

Nobuo Takeda; Haruo Komatsu; Kiyoshi Takahashi

1993-01-01

23

Structure-Property Relationships in Thermoplastic Pseudo-Interpenetrating Polymer Networks. I. Phase Morphology  

Microsoft Academic Search

Pseudo-thermoplastic interpenetrating polymer networks (p-TIPNs) prepared by mechanical mixing of a crystallizable polyurethane (CPU) and styrene\\/acrylic acid random copolymer (S\\/AA) were characterized by specific heat capacity measurements in the temperature interval 133–433 K, as well as by wide-angle and small-angle X-ray scattering. It was established that:1. Crystallizability of BAG is the main cause of microphase-separated morphology of CPU.2. Limited miscibility

L. M. Sergeeva; O. P. Grigoryeva; O. N. Zimich; E. G. Privalko; V. I. Shtompel; V. P. Privalko; P. Pissis; A. Kyritsis

1997-01-01

24

Characterization of thermoplastic interpenetrating polymer networks by various thermal analysis techniques  

Microsoft Academic Search

Thermoplastic interpenetrating polymer networks (t-IPNs), prepared by melting and pressing of crystallizable polyurethane (CPU) and styrene\\/acrylic acid random copolymer (S\\/AA) in wide ranges of composition, were investigated by the combination of various thermal analysis techniques: differential scanning calorimetry (DSC), thermomechanical analysis (TMA), thermally stimulated depolarization currents (TSDC) and thermally stimulated conductivity (TSC) measurements, as well as broadband dielectric relaxation spectroscopy

A. S Vatalis; C. G Delides; G Georgoussis; A Kyritsis; O. P Grigorieva; L. M Sergeeva; A. A Brovko; O. N Zimich; V. I Shtompel; E Neagu; P Pissis

2001-01-01

25

Thermal properties of thermoplastic starch\\/synthetic polymer blends with potential biomedical applicability  

Microsoft Academic Search

Previous studies shown that thermoplastic blends of corn starch with some biodegradable synthetic polymers (poly(e-caprolactone), cellulose acetate, poly(lactic acid) and ethylene-vinyl alcohol copolymer) have good potential to be used in a series of biomedical applications. In this work the thermal behavior of these structurally complex materials is investigated by differential scanning calorimetry (DSC) and by thermogravimetric analysis (TGA). In addition,

J. F. Mano; D. Koniarova; R. L. Reis

2003-01-01

26

RHEOLOGICAL PROPERTIES & MOLECULAR WEIGHT DISTRIBUTIONS OF FOUR PERFLUORINATED THERMOPLASTIC POLYMERS  

SciTech Connect

Dynamic viscosity measurements and molecular weight estimates have been made on four commercial, amorphous fluoropolymers with glass transitions (Tg) above 100 C: Teflon AF 1600, Hyflon AD 60, Cytop A and Cytop M. These polymers are of interest as binders for the insensitive high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) because of their high density and Tg above ambient, but within a suitable processing range of TATB. As part of this effort, the rheological properties and molecular weight distributions of these polymers were evaluated.

Hoffman, D M; Shields, A L

2009-02-24

27

Roles of work of adhesion between carbon blacks and thermoplastic polymers on electrical properties of composites.  

PubMed

The effect of the work of adhesion between carbon blacks and different thermoplastic polymers on the positive temperature coefficient (PTC) of composites was investigated. Thermoplastic polymers, such as EVA, LDPE, LLDPE, HDPE, and PP, were used with the addition of 30 wt% of carbon blacks. The work of adhesion based on the surface free energy of a composite was studied in the context of two-liquid contact angle measurements using deionized water and diiodomethane. It was observed that the resistivity on PTC behavior was greatly increased near the crystalline melting temperature, due to the thermal expansion of polymeric matrix. It was shown that the PTC intensity defined as the ratio of the maximum resistivity (rho(max)) to the resistivity at room temperature (rho(RT)) had the largest value on CB/HDPE composites. From the experimental results, the decrease in the work of adhesion induced by interactions between carbon black surfaces and polymer chains is an important factor in the fabrication of a PTC composite. PMID:12702379

Park, Soo-Jin; Kim, Hyun-Chel; Kim, Hak-Yong

2002-11-01

28

Biomedical application of commercial polymers and novel polyisobutylene-based thermoplastic elastomers for soft tissue replacement.  

PubMed

Novel polyisobutylene-based thermoplastic elastomers are introduced as prospective implant materials for soft tissue replacement and reconstruction. In comparison, poly(ethylene terephthalate) (PET), poly(tetrafluoroethylene) (PTFE), polypropylene (PP), polyurethanes (PU), and silicones are outlined from well-established implant history as being relatively inert and biocompatible biomaterials for soft tissue replacement, especially in vascular grafts and breast implants. Some general considerations for the design and development of polymers for soft tissue replacement are reviewed from the viewpoint of material science and engineering, with special attention to synthetic materials used in vascular grafts and breast implants. PMID:15244424

Puskas, Judit E; Chen, Yaohong

29

Strategies for the synthesis of thermoplastic polymer nanocomposite materials with high inorganic filling fraction.  

PubMed

The governing parameters controlling the miscibility of particle additives within polymeric host media are analyzed for the particular case of silica particle fillers embedded within a poly(methyl methacrylate) (PMMA) matrix. For athermal polymer-graft modification of particles (corresponding to equal chemical composition of graft and matrix polymer), compatibility is found to be a sensitive function of the degree of polymerization of graft and host polymer chains as well as the particle radius. In agreement with theoretical predictions, uniform particle dispersion is observed if the degree of polymerization of grafted chains is comparable to (or exceeds) the corresponding value of the polymer matrix. The resulting restriction to high degree of polymerization limits the accessible inorganic fraction that is attainable in athermal particle/polymer blends. In contrast, favorable interaction between grafted polymer chains and the polymeric host (as realized in the case of poly(styrene-r-acrylonitrile)-grafted particles embedded within PMMA matrix) is shown to facilitate thermodynamically stable and uniform particle dispersion across the entire compositional range even in the limit of large particle size, short grafted chains, and high molecular matrix chains. The synthesis of thermoplastic composite materials with inorganic fraction exceeding 50 vol % combining quantitative optical limiting within the UV frequency range and polymer-like mechanical properties is demonstrated. PMID:23786358

Ojha, Satyajeet; Dang, Alei; Hui, Chin Ming; Mahoney, Clare; Matyjaszewski, Krzysztof; Bockstaller, Michael R

2013-07-01

30

IR laser radiation induced changes in the IR absorption spectra of thermoplastic and thermosetting polymers  

NASA Astrophysics Data System (ADS)

This paper demonstrates that powerful laser radiation causes changes in the absorbance spectra of epoxy resin, polyethylene and polysulfone. Thin polymer films were located between IR AgBrCl optical fibres and exposed to the radiation of a CO2 laser. The output of the laser source was varied in the range 0-8.5 W. The absorbance spectra were recorded using a Fourier transform infrared (FTIR) spectrophotometer. It was revealed that characteristic polymer absorbance peaks decay under exposure to the powerful IR light. The apparent dependence of peak magnitude on IR radiation power has been established. We showed that the phenomenon of the absorbance peak disappearances associated with the polymers - thermoplastic (including an engineering polymer such as polysulfone) and thermosetting - is of a threshold nature. The mathematical theory of the observed effect was derived. We propose that the effect under discussion is caused by the oxygen-free thermal action of IR radiation on the chemical structure of the polymer materials. The revealed effect could be effectively used to lower the losses in adhesive contacts of IR optical elements. The novelty of the proposed method lies in the fact that thermal treatment is localized strictly within the adhesive layer; optical elements to be contacted (fibres, lenses, etc) which are highly IR transparent do not experience the IR radiation, but the polymer adhesive is subjected to a temperature rise.

Bormashenko, Edward; Pogreb, Roman; Sheshnev, Avigdor; Shulzinger, Eugene; Bormashenko, Yelena; Katzir, Abraham

2001-07-01

31

The photochromic properties of indoline spirooxazine-thermoplastic polymer systems obtained by supercritical fluid impregnation  

NASA Astrophysics Data System (ADS)

The impregnation of thermoplastic polymers (polyethylene, polypropylene, polymethyl methacrylate, and polycarbonate) with photochromic compounds from the class of indoline spirooxazines in supercritical carbon dioxide (SC-CO2) was studied. The concentration of the photochrome and the kinetics of decolorization of its colored form depended strongly on the type of the polymer matrix and the structure of spirooxazine. The introduction of 1,3',3'-trimethylspiro(indoline-2',3-3H-anthraceno[2,1-b][1,4]oxazine) (SAO) into polycarbonate caused anomalous stabilization (the prolonged conservation of the excited colored form of SAO in the polymer matrix). In contrast to other photochrome-polymer pairs, after supercritical impregnation into polycarbonate, at least 10% of all SAO molecules were in the colored form, which was highly stable and did not decolorize after 150 days; the rest of the impregnated SAO molecules were localized in the matrix as individual molecules, partially colorized after matrix relaxation, or nanocrystals of characteristic sizes ˜10-20 nm. The mechanisms of the anomalous stabilization of the colored SAO form in the polycarbonate matrix are discussed.

Glagolev, N. N.; Solov'eva, A. B.; Kotova, A. V.; Shashkova, V. T.; Zapadinskii, B. I.; Zaichenko, N. L.; Kol'Tsova, L. S.; Shienok, A. I.; Timashev, P. S.; Bagratashvili, V. N.

2009-05-01

32

Tailoring normal adhesion of arrays of thermoplastic, spring-like polymer nanorods by shaping nanorod tips.  

PubMed

The tip shape of contact elements in hairy adhesion systems is crucial for proper contact formation and adhesion enhancement. While submicrometer terminal contact elements show much better adhesion performance than their larger counterparts, shaping their tips so as to maximize normal adhesion has remained challenging. We prepared durable nanorod arrays consisting of stiff, highly entangled thermoplastic polymers with rationally shaped tips by replication of anodic aluminum oxide (AAO). Nanorod arrays with pancake-like tips showed pronounced normal dry adhesion already for small loading forces. For small loading forces, adhesion forces significantly exceeded the loading forces. Both the absence of hysteresis in force/displacement curves and the pronounced durability of the nanorods in series of repeated attachment/detachment cycles suggest that the nanorods behave like elastic springs. Experimental load-adhesion curves were reproduced with a modified Schargott-Popov-Gorb (SPG) model, assuming that contacts between probe and individual nanorods are sequentially formed with increasing indentation depth. PMID:22746364

Xue, Longjian; Kovalev, Alexander; Thöle, Florian; Rengarajan, Gopalakrishnan Trichy; Steinhart, Martin; Gorb, Stanislav N

2012-07-13

33

Study of double-side ultrasonic embossing for fabrication of microstructures on thermoplastic polymer substrates.  

PubMed

Double-side replication of polymer substrates is beneficial to the design and the fabrication of 3-demensional devices. The ultrasonic embossing method is a promising, high efficiency and low cost replication method for thermoplastic substrates. It is convenient to apply silicon molds in ultrasonic embossing, because microstructures can be easily fabricated on silicon wafers with etching techniques. To reduce the risk of damaging to silicon molds and to improve the replication uniformity on both sides of the polymer substrates, thermal assisted ultrasonic embossing method was proposed and tested. The processing parameters for the replication of polymethyl methacrylate (PMMA), including ultrasonic amplitude, ultrasonic force, ultrasonic time, and thermal assisted temperature were studied using orthogonal array experiments. The influences of the substrate thickness, pattern style and density were also investigated. The experiment results show that the principal parameters for the upper and lower surface replication are ultrasonic amplitude and thermal assisted temperature, respectively. As to the replication uniformity on both sides, the ultrasonic force has the maximal influence. Using the optimized parameters, the replication rate reached 97.5% on both sides of the PMMA substrate, and the cycle time was less than 50 s. PMID:23630605

Luo, Yi; Yan, Xu; Qi, Na; Wang, Xiaodong; Wang, Liangjiang

2013-04-22

34

Characterization of thermoplastic apparent interpenetrating polymer networks CPU-S\\/AA by WAXS, SAXS, TSDC, DRS and DMA  

Microsoft Academic Search

Thermoplastic apparent interpenetrating polymer networks (t-AIPNs), prepared by mechanical blending in a common solvent of crystallisable polyurethane (CPU) and styrene\\/acrylic acid random copolymer (S\\/IAA), were investigated by means of wide-angle and small-angle X-ray scattering (WAXS and SAXS), thermally stimulated depolarization currents (TSDC) measurements in the temperature range 77-420 K, dielectric relaxation spectroscopy (DRS) measurements in the frequency range 10-2-106 Hz

E. Neagu; R. Neagu; G. Georgoussis; O. P. Grigoryeva; L. M. Sergeeva; A. A. Brovko; O. N. Zimich; V. I. Shtompel; A. Kyritsis; S. Vatalis; C. G. Delides

1999-01-01

35

Review of potential processing techniques for the encapsulation of wastes in thermoplastic polymers  

Microsoft Academic Search

Thermoplastic encapsulation has been extensively studied at Brookhaven National Laboratory`s (BNL) Environmental and Waste Technology Center (EWTC) as a waste encapsulation technology applicable to a wide range of waste types including radioactive, hazardous and mixed wastes. Encapsulation involves processing thermoplastic and waste materials into a waste form product by heating and mixing both materials into a homogeneous molten mixture. Cooling

B. R. Patel; P. R. Lageraaen; P. D. Kalb

1995-01-01

36

In Situ Reinforcing Elastomer Composite Based on Polyolefinic Thermoplastic Elastomer and Thermotropic Liquid Crystalline Polymer  

NASA Astrophysics Data System (ADS)

In situ reinforcing elastomer composites based on Santoprene thermoplastic elastomer, a polymerized polyolefin compound of ethylene-propylene-diene monomer (EPDM)/polypropylene (PP), and a thermotropic liquid crystalline polymer (TLCP), Rodrun LC3000, were prepared using a single-screw extruder. The rheological behavior, morphology, mechanical and thermal properties of the blends containing various LC3000 contents were investigated. All neat components and their blends exhibited shear thinning behavior. With increasing TLCP content, processability became easier because of the decrease in melt viscosity of the blends. Despite the viscosity ratio of dispersed phase to the matrix phase for the blend system is lower than 0.14, most of TLCP domains in the blends containing 5-10 wt% LC3000 appeared as droplets. At 20 wt% LC3000 or more, the domain size of TLCP became larger due to the coalescence of liquid TLCP threads that occurred during extrusion. The addition of LC3000 into the elastomer matrix enhanced the initial tensile modulus considerably whereas the extensibility of the blends remarkably decreased with addition of high TLCP level (>20wt%). The results obtained from thermogravimetric analysis suggested that the incorporation of LC3000 into Santoprene slightly improved the thermal resistance both in nitrogen and in air.

Saikrasun, Sunan; Phoban, Yuwararat; Limpisawasdi, Panpirada; Amornsakchai, Taweechai

37

Clearweld laser transmission welding of thermoplastic polymers: light transmission and color considerations  

NASA Astrophysics Data System (ADS)

The past three years has seen the evolution and maturation of Clearweld technology as a tool which is readily employable for the transmission laser welding of thermoplastic and some thermoset polymers using near infrared lasers and inks uniquely chosen and targeted to absorb the laser light at the intended laser weld joint in order to efficiently and rapidly effectuate the weld. This paper will discuss the novel and useful transmission values and minimal haze characteristics of the welded polymeric part as compared to the unwelded component parts both in the nascent state and in parts prepared for the laser welding operation. Further presentation will be made relative to the color hue recession toward neutrality and the goal of colorlessness as the parts are taken from these prewelded states to the welded final part. Among the polymeric materials discussed are polycarbonate, cast polymethylmethacrylate, nylon and polyester. Detailed attention is given to the Clearweld process used in these welding operations as well as to the employed welding equipment, ink deposition, laser welding process parameters and full spectral characteristics of all components and welded parts. Mechanical characteristics of resultant welds are offered for verification and comparison of the process integrity as a novel and very useful manufacturing tool.

Hartley, Scott; Sallavanti, Robert A.

2003-02-01

38

Modification of Ethylene Propylene Diene Terpolymer Rubber by Some Thermoplastic Polymers  

Microsoft Academic Search

Blends of ethylene propylene diene terpolymer (EPDM) rubber with thermoplastic polyolefins such as low?density polyethylene (LDPE), high?density polyethylene (HDPE), high molecular weight polypropylene (PP), and polypropylene random copolymer grade (PP?R) were prepared by melt mixing. The physico?mechanical properties, equilibrium swelling in benzene, and aging properties of the binary blends were investigated, analyzing the effect of the rubber\\/thermoplastics ratio and the

E. M. Sadek; A. M. Motawie

2003-01-01

39

Effect of multiwalled carbon nanotubes on tensile stress-strain diagrams of amorphous-crystalline thermoplastic polymers  

NASA Astrophysics Data System (ADS)

The effect of multiwalled carbon nanotubes (MWNTs) on the stress-strain diagrams of uniaxially extended thin films of low-density polyethylene (LDPE) and poly(vinyl alcohol) (PVA) has been studied. MWNTs were synthesized by the thermocatalytic method. The introduction of MWNTs decreases the plasticity of LDPE, while significantly increasing that of PVA. The results can be explained by assuming that crystallites are key structural elements that ensure large plastic deformation. The manifestation of the plasticity of crystallites implies that amorphous regions occur in a rubberlike state. Both of these prerequisites are important for the mechanics of amorphous-crystalline thermoplastic polymers.

Ginzburg, B. M.; Tuichiev, Sh.; Rashidov, D.; Tabarov, S. Kh.; Ivashchenko, P. I.

2010-09-01

40

Development of Thermoplastic Structural Adhesives.  

National Technical Information Service (NTIS)

Six different classes of thermoplastic polymers having high temperature capabilities (+300 deg F service) were surveyed after studying available data; five polymers from three different classes were screened for adhesive shear properties. The screening wa...

S. G. Hill J. T. Hoggatt

1977-01-01

41

Fungal degradation of the thermoplastic polymer poly-?-hydroxybutyric acid (PHB) under simulated deep sea pressure  

Microsoft Academic Search

Little is known about marine filamentous fungi and yeasts, almost nothing about their life and metabolism under deep sea conditions. Data on growth and metabolic activity give insight into the role of organisms in the marine habitat. Degradation studies on pollutants, such as polymeric thermoplasts, provide information about the self-cleaning capacity of a habitat. Therefore, recently isolated fungal strains from

K. E. Gonda; D. Jendrossek; H. P. Molitoris

2000-01-01

42

Modeling and Simulation of the Flow of a Thermoplastic Polymer during Filling of a Cylindrical Micro-Cavity  

NASA Astrophysics Data System (ADS)

This work is related to experiments and modelling concerning viscous polymer flow such as cyclo-olefin polymer (COP) and cyco-olefin copolymer (COC) arising in the hot embossing process in order to understand and predict the filling of microcavities. The simulation results are obtained for axisymmetric geometries. The filling time and the dimensions of polymer with the rheological and experimental process parameters are obtained. From the variations of the radius characterizing the squeeze flow of the polymers between plates with or without cavities, it is possible to relate the rheological properties (fluidity index, consistency, melt flow index and viscosity) to the aptitude of the polymers to reproduce the geometrical shape and surface asperities of a microstructured mould. The flow imposed to the polymeric material in shear or elongational mode was correlated to the rheological approach. This approach allows to better understand the compression of thermoplastic disks as well as the filling mechanism of cylindrical cavities while providing a predictive approach for the of embossing pressure during the process.

Sahli, M.; Gelin, J. C.; Malek, C. Khan; Roques-Carmes, C.

2007-05-01

43

Comparison of glow argon plasma-induced surface changes of thermoplastic polymers  

NASA Astrophysics Data System (ADS)

Modification of high-density polyethylene (PE), polytetrafluoroethylene (PTFE), polystyrene (PS), polyethyleneterephthalate (PET) and polypropylene (PP) by Ar plasma was studied. The amount of the ablated material was determined by gravimetry. Wettability of polymers after the plasma treatment was determined from the contact angle measurement. The changes in the surface morphology of polymers were observed using atomic force microscopy (AFM). Chemical structure of modified polymers was characterized by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Surface changes were also studied by the determination of electrokinetic potential (?-potential). It was found that under the plasma treatment the polymers are ablated and their surface morphology and roughness are changed dramatically. XPS measurements indicate an oxidation of the polymer surface. The plasma treatment results in a dramatic increase of the ?-potential. EPR data show different radical amount present on the treated surface of all polymers. Most significant changes due to the degradation of polymer chains are observed on PTFE.

?ezní?ková, A.; Kolská, Z.; Hnatowicz, V.; Stopka, P.; Švor?ík, V.

2011-01-01

44

The effects of physico-chemical interactions and polymer grafting on interfacial adhesion in thermoplastic composites  

NASA Astrophysics Data System (ADS)

The effects of physico-chemical interactions between the carbon fiber and Bisphenol-A polycarbonate matrix was investigated to understand the factors governing the interfacial adhesion in thermoplastic matrix composites. It was found that, the changes in the amount of oxygen functionality achieved through electrochemical oxidative surface treatment of the carbon fibers didn't affect the level of adhesion, indicating negligible polar and hydrogen bond formation. Composites fabricated from these fibers that were subsequently passivated through thermal hydrogenation up to 1000°C, which removed all the oxygen functionality without affecting the fiber topography, indicated that the mechanical interlocking between the fiber and the matrix didn't have a strong influence on the interfacial adhesion. Grafting low molecular weight BPA-PC and high molecular weight PMMA on to the fiber surface improved the interfacial adhesion. However, the level of improvement was observed to be independent of the fiber surface treatment and the molecular weight of the grafted chains. These results are consistent with the cohesive zone models proposed for the chain pull out and chain scission observed in block copolymers.

Raghavendra, Venkat Krishna

45

Preparation of Thermoplastic X-ray Masks for Medical Applications  

Microsoft Academic Search

The objective of this thesis was to study the appropriate polymer for preparation of thermoplastic masks for medical applications. The commercial thermoplastic mask was characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The results indicated that the type of polymer being used is polycaprolactone. The tensile strength, hardness and impact strength of the commercial thermoplastic mask

Jindarat Pimsamarn

46

69 Cent Look at Thermoplastic Softening.  

National Technical Information Service (NTIS)

The objectives are to demonstrate the change in mechanical properties of a thermoplastic polymer when the polymer is heated above the glass transition temperature. The instructor or student can perform this demonstration. In preparation for the demonstrat...

L. S. Vanasupa

1993-01-01

47

Low platinum loading electrodes for polymer electrolyte fuel cells fabricated using thermoplastic ionomers  

Microsoft Academic Search

Low platinum loading catalyst layers for polymer electrolyte fuel cells (PEFCs) consist of a thin film of highly inter-mixed ionomer and catalyst that is applied to the electrolyte membrane. High performances are achieved with loadings as low as 0.12 mg Pt cm?2 at the cathode and even lower loadings are required at the anode. However, the long-term performance of these

Mahlon S. Wilson; Judith A. Valerio; Shimshon Gottesfeld

1995-01-01

48

IR laser radiation induced changes in the IR absorption spectra of thermoplastic and thermosetting polymers  

Microsoft Academic Search

This paper demonstrates that powerful laser radiation causes changes in the absorbance spectra of epoxy resin, polyethylene and polysulfone. Thin polymer films were located between IR AgBrCl optical fibres and exposed to the radiation of a CO2 laser. The output of the laser source was varied in the range 0-8.5 W. The absorbance spectra were recorded using a Fourier transform

Edward Bormashenko; Roman Pogreb; Avigdor Sheshnev; Eugene Shulzinger; Yelena Bormashenko; Abraham Katzir

2001-01-01

49

A Process for Semi-Solid Moulding of High Viscosity Thermoplastic Polymers  

NASA Astrophysics Data System (ADS)

A new moulding process for manufacturing micro parts made from high viscosity polymers has been developed as a result of a feasibility study. The process basically involves compression moulding of a polymeric preform by heating it up to its semi-solid state, i.e. between its glass transition temperature and melting temperature. The apparatus is made up of three main parts: a forming device, a single cavity micro mould and an induction heating system. The processing technique was successfully tested in the manufacturing of 10 mm round discs with a flange and inner bore using high viscosity polymers such as polyphenylene sulfide (PPS), polyetheretherketone (PEEK), ultra-high molecular weight polyethylene (UHMW PE) and polytetrafluoroethylene (PTFE). In a further miniaturization study, U-shaped micro seals with an outer diameter up to 2.5 mm were also successfully manufactured from non-injection mouldable PTFE. Thus, the new process is a realistic alternative technique to the existing micro moulding processes with respect to its capability to process a huge variety of polymers, even ultra high viscosity materials and the possibility to create micro parts with non-uniform wall thickness distributions.

Frick, Achim; Rochman, Arif; Martin, Peter

2011-05-01

50

The Effect of multi-reprocessing on the structure and characteristics of thermoplastic elastomers based on recycled polymers  

Microsoft Academic Search

The effect of multi-reprocessing on the phase structure and characteristics is studied for thermoplastic elastomers based\\u000a on recycled high-density polyethylene (HDPE), ethylene-propylene-diene rubber (ternary copolymer of ethylene, propylene, and\\u000a 5-ethylidene-2-norbornene) (EPDM), and recycled ground tire rubber (RGTR). Analysis of the viscous flow characteristics of\\u000a thermoplastic elastomers shows that, independently of the number of processing cycles, all samples are characterized by

O. P. Grigoryeva; A. M. Fainleb; V. F. Shumskii; V. A. Vilenskii; N. V. Kozak; N. V. Babkina

2009-01-01

51

Synthesis of Energetic Polyester Thermoplastic Homopolymers and Energetic Thermoplastic Elastomers Formed Therefrom.  

National Technical Information Service (NTIS)

For many years, DREV has been involved in the synthesis of energetic thermoplastic elastomers (ETPEs) based on linear glycidyl azide polymer (GAP). These polymers are physically-crosslinked rubbery materials that can be melted, dissolved or recycled and c...

G. Ampierman S. Brochu M. Desjardins

2001-01-01

52

Foamability of Thermoplastic Vulcanizates Blown with Various Physical Blowing Agents  

Microsoft Academic Search

Thermoplastic vulcanizate (TPV) is a special class of thermoplastic elastomers (TPEs) made of a rubber\\/plastic polymer mixture in which the rubber phase is highly vulcanized. It is prepared by melt mixing a thermoplastic with an elastomer and by in situ crosslinking of the rubber phase. Currently, TPV is replacing EPDM rubber dramatically because of the impressive advantages for automotive sealing

Seong G. Kim; Chul B. Park; Mohini Sain

2008-01-01

53

A high throughput, controllable and environmentally benign fabrication process of thermoplastic nanofibers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Continuous and uniform yarns of thermoplastic nanofibers were prepared via direct melt extrusion of immiscible blends of thermoplastic polymers with CAB and subsequent extraction removal of CAB. Ratios of thermoplastic/sacrificial polymers, melt viscosity, and interfacial tensions affect the formati...

54

Super Tough Engineering Thermoplastic Blends by Reactive Compatibilization  

Microsoft Academic Search

Polymers generally have the advantages of being lightweight, ease of fabrication into complex shapes, and low cost. Most engineering thermoplastics are combined with other polymers and inorganic materials to obtain the balance of properties required by specific applications. This presentation will examine the formulation of blends of engineering thermoplastics with rubber (or rubber containing materials) to achieve super tough compositions

Donald Paul

2001-01-01

55

Thermoplastic Electronic Packaging: Low Cost - High Versatility  

Microsoft Academic Search

Thermoplastics have started to gain acceptance in some of the more challenging areas of advanced packaging, including MEMS, where lower cost, cavity style packages are required. Thermoplastics, like LCP, PPS and PEEK, can withstand exposure to over 300oC thus assuring lead-free solder capability. Many polymers offer superior moisture resistance, can be formed into micro-precision packages in just seconds, and are

Ken Gilleo; RI Rita Mohanty; Gerald Pham-Van-Diep; Dennis Jones

56

Thermal degradation of thermoplastic and thermosetting polymers induced by laser radiation and its study by FTIR spectroscopy  

Microsoft Academic Search

It is demonstrated that powerful laser radiation causes changes in absorbance spectra of an epoxy resin, polyethylene and polysulfone. Thin polymer films were located between infrared AgBrCl optical fibers and exposed to the radiation of a CO2 laser. The output of the laser source was varied in the range 0–8.5 W. Absorbance spectra were measured by FTIR spectrometry. It was

Edward Bormashenko; Roman Pogreb; Avigdor Sheshnev; Eugene Shulzinger; Yelena Bormashenko; Shimon Sutovski; Zosya Pogreb; Abraham Katzir

2001-01-01

57

Feasibility of bloodless liver resection using Lumagel, a reverse thermoplastic polymer, to produce temporary, targeted hepatic blood flow interruption  

PubMed Central

Background Lumagel, a reverse thermosensitive polymer (RTP), provides targeted flow interruption to the kidney by reversibly plugging segmental branches of the renal artery, allowing blood-free partial nephrectomy. Extending this technology to the liver requires the development of techniques for temporary occlusion of the hepatic artery and selected portal vein branches. Methods A three-phased, 15 swine study was performed to determine feasibility, techniques and survival implications of using Lumagel for occlusion of inflow vessels to targeted portions of the liver. Lumagel was delivered using angiographic techniques to sites determined by pre-operative 3-D vascular reconstructions of arterial and venous branches. During resection, the targeted liver mass was resected without vascular clamping. Three survival swine were sacrificed at 3 weeks; the remainder at 6 weeks for pathological studies. Results Six animals (100%) survived, with normal growth, blood tests and no adverse events. Three left lateral lobe resections encountered no bleeding during resection; one right median resection bled; two control animals bled significantly. Pre-terminal angiography and autopsy showed no local pathology and no remote organ damage. Conclusions Targeted flow interruption to the left lateral lobe of the swine liver is feasible and allows resection without bleeding, toxicity or pathological sequelae. Targeting the remaining liver will require more elaborate plug deposition owing to the extensive collateral venous network.

Pomposelli, James J; Akoad, Mohamed; Flacke, Sebastian; Benn, James J; Solano, Mauricio; Kalra, Aarti; Madras, Peter N

2012-01-01

58

Nonlinear viscoelastic characterization of molten thermoplastic vulcanizates (TPV) through large amplitude harmonic experiments  

Microsoft Academic Search

The so-called thermoplastic vulcanizates (TPV) are essentially blends of a crystalline thermoplastic polymer (e.g., polypropylene)\\u000a and a vulcanizable rubber composition, prepared through a special process called dynamic vulcanization, which yields a fine\\u000a dispersion of micron-size crosslinked rubber particles in a thermoplastic matrix. Such materials are by nature complex polymer\\u000a systems, i.e., multiphase, heterogeneous, typically disordered materials for which structure is

Jean L. Leblanc

2007-01-01

59

A polymer network based on thermoplastic polyurethane and ethylene–propylene–diene elastomer via melt blending: morphology, mechanical properties, and rheology  

Microsoft Academic Search

Blends of thermoplastic polyurethane (TPU) and ethylene–propylene–diene elastomer (EPDM) were prepared via a melt blending, and morphology, mechanical properties, and rheology were studied. Scanning electron microscopy (SEM) micrographs demonstrated that a network of EPDM domain was formed in TPU matrix, and became finer and more perfect with addition of 8 wt% EPDM into TPU. Dynamic mechanical analysis (DMA) and Fourier

Xiaodong Wang; Xin Luo

2004-01-01

60

PVD coating for optical applications on temperature-resistant thermoplastics  

NASA Astrophysics Data System (ADS)

The performance of the high temperature resistant polymers Pleximid, APEC and Ultrason as substrate materials in plasma-assisted physical vapor deposition processes was studied and compared with well-known thermoplastics for optical applications. Different effects of UV irradiation and plasma exposure on the polymers' optical features, surface energy and adhesion properties for oxide layers, typically used for interference multilayer coatings, are shown.

Munzert, Peter; Schulz, Ulrike; Kaiser, Norbert

2004-02-01

61

Strong thermoplastic elastomers created using nickel nanopowder  

Microsoft Academic Search

We have decided to investigate whether addition of nickel (Ni) to a thermoplastic elastomer (TPE) will make TPE properties\\u000a better for demanding applications. We have found that Ni particles moved well during low (100 °C) temperature blending, with\\u000a the polymer providing more uniform particle dispersion. In contrast, at 160 °C, lower viscosity prevented particle dispersion\\u000a and supported Ni agglomerations. All samples processed

Witold BrostowMartina Brozynski; Martina Brozynski; Tea Datashvili; Oscar Olea-Mejía

62

A nanostructured carbon-reinforced polyisobutylene-based thermoplastic elastomer.  

PubMed

This paper presents the synthesis and characterization of a polyisobutylene (PIB)-based nanostructured carbon-reinforced thermoplastic elastomer. This thermoplastic elastomer is based on a self-assembling block copolymer having a branched PIB core carrying -OH functional groups at each branch point, flanked by blocks of poly(isobutylene-co-para-methylstyrene). The block copolymer has thermolabile physical crosslinks and can be processed as a plastic, yet retains its rubbery properties at room temperature. The carbon-reinforced thermoplastic elastomer had more than twice the tensile strength of the neat polymer, exceeding the strength of medical grade silicone rubber, while remaining significantly softer. The carbon-reinforced thermoplastic elastomer displayed a high T(g) of 126 degrees C, rendering the material steam-sterilizable. The carbon also acted as a free radical trap, increasing the onset temperature of thermal decomposition in the neat polymer from 256.6 degrees C to 327.7 degrees C. The carbon-reinforced thermoplastic elastomer had the lowest water contact angle at 82 degrees and surface nano-topography. After 180 days of implantation into rabbit soft tissues, the carbon-reinforced thermoplastic elastomer had the thinnest tissue capsule around the microdumbbell specimens, with no eosinophiles present. The material also showed excellent integration into bones. PMID:20034664

Puskas, Judit E; Foreman-Orlowski, Elizabeth A; Lim, Goy Teck; Porosky, Sara E; Evancho-Chapman, Michelle M; Schmidt, Steven P; El Fray, Miros?awa; Piatek, Marta; Prowans, Piotr; Lovejoy, Krystal

2009-12-24

63

Modeling of temperature distribution in ultrasonic welding of thermoplastics for various joint designs  

Microsoft Academic Search

Use of engineering plastics in structural and non-structural applications is rapidly increasing. As the demand for plastics increases so does the requirements for joining. Of the many techniques that are available for joining of thermoplastics, ultrasonic welding is one of the preferred processes. Thermoplastic polymers are categorized according to their molecular structure as amorphous and semi-crystalline. Ultrasonic welding of these

K. S. Suresh; M. Roopa Rani; K. Prakasan; R. Rudramoorthy

2007-01-01

64

Film blowing of thermoplastic starch  

Microsoft Academic Search

Thermoplastic starch materials are often based on a combination of starch, glycerol and water. In the present study, two potato starch grades were employed; a native (natural) grade and an oxidised and hydroxypropylated grade of the native material, in order to produce the thermoplastic material. The primary aim of the study was to identify possible routes for film blowing thermoplastic

Mats Thunwall; Vanda Kuthanová; Antal Boldizar; Mikael Rigdahl

2008-01-01

65

Welds in thermoplastic composite materials  

NASA Astrophysics Data System (ADS)

Welding methods are reviewed that can be effectively used for joining of thermoplastic composites and continuous-fiber thermoplastics. Attention is given to the use of ultrasonic, vibration, hot-plate, resistance, and induction welding techniques. The welding techniques are shown to provide complementary weld qualities for the range of thermoplastic materials that are of interest to industrial and technological applications.

Taylor, N. S.

66

Automated thermoplastic holographic camera development  

Microsoft Academic Search

The development of an automated thermoplastic holographic camera, which gives reproducible results from cycle to cycle and from sample to sample, is reported. The thermoplastic device has a conventional sandwich geometry consisting of a thin transparent conductor, a thin layer of organic photoconductor, and a thermoplastic layer with a softening temperature of roughly 70 C. A major innovation of the

T. C. Lee; J. Skogen; R. Schulze; E. Bernal; G. J. Lin; T. Daehlin; M. Campbell

1980-01-01

67

Thermoplastic polycarbonate/polyester blend compositions with improved mechanical properties  

US Patent & Trademark Office Database

Disclosed is a thermoplastic composition comprising a mixture of from 10 to 98 weight % of a polycarbonate polymer, from 2 to 90 weight % of a polyester polymer comprising structures derived from a diol compound having the structure (A) HO--Z--OH, wherein Z is a C.sub.1 to C.sub.36 linear aliphatic radical, a C.sub.3 to C.sub.36 branched aliphatic or cycloaliphatic radical, a C.sub.6 to C.sub.36 aryl radical, or a C.sub.7 to C.sub.36 alkylaryl radical, and a diacid compound having the structure (B) HOOC--CH.sub.2CH.sub.2--COOH, from 0 to 5 weight % of a polylactic acid polymer, wherein the sum of the polycarbonate polymer, the polyester polymer, and the polylactic acid polymer is equal to 100 weight %. The thermoplastic composition has improved mechanical properties.

2011-12-06

68

Evaluation of enzymatic degradation based on the quantification of glucose in thermoplastic starch and its characterization by mechanical and morphological properties and NMR measurements  

Microsoft Academic Search

Biodegradable polymers represent a promising solution to the environmental problem of plastic waste disposal. Among the candidate polymers, starch, a low-cost natural polymer, can be processed as a thermoplastic. In this work, thermoplastic starch containing glycerol (20, 30 or 40wt%) was prepared by extrusion. The mechanical properties of the blends were assessed by tensile stress at break, elongation at break

D. S. Rosa; C. L. Carvalho; F. Gaboardi; M. L. Rezende; M. I. B. Tavares; M. S. M. Petro; M. R. Calil

2008-01-01

69

Microwave welding of thermoplastics  

Microsoft Academic Search

The aim of this work was to develop a new and versatile method for welding thermoplastics using microwave energy. A multimode cavity applicator was developed including features designed to deliver an even energy density and to apply weld pressure. A review of possible microwave susceptible implant materials was undertaken and results of welding trials using several candidate materials showed that

R. J. Wise; I. D. Froment

2001-01-01

70

Review of Recent Developments in Joining High-Performance Thermoplastic Composites.  

National Technical Information Service (NTIS)

There is currently a great deal of interest in the use of thermoplastic polymers as matrices in fiber reinforced composites for high performance applications, such as those encountered in the aerospace industry. These materials include polyether ether ket...

K. C. Cole

1991-01-01

71

Quantitative Measurement of Cellulosic Filler Dispersion in Thermoplastic Composites  

Microsoft Academic Search

An image analysis technique was employed to quantitatively measure cellulosic filler dispersion in linear low density polyethylene (LLDPE) polymer for the assessment of a high intensity shear compounding process in manufacturing wood-fiber thermoplastic composites. Graphic images of samples obtained with a confocal microscope were analyzed by assigning different colors to the pixels which had different laser intensities depending on different

Byung-Dae Park; John J. Balatinecz

1997-01-01

72

The Strength of Thermoplastic Materials. Part 1: Critical Stress Cracking in Uniaxial Tension of Polymers with Phenylene Groups in the Main Chain.  

National Technical Information Service (NTIS)

Results on critical stresses at which catastrophic failure occurs within a few seconds of liquid contact with polymers such as polyethylene terephtalate, bakelite phenoxy resins, polycarbonate, polysulfone, and polyphenylene oxide under uniaxial tension a...

B. J. Macnulty

1973-01-01

73

Thermal formation of PBDD\\/F from tetrabromobisphenol A––a comparison of polymer linked TBBP A with its additive incorporation in thermoplastics  

Microsoft Academic Search

For a long period, polybrominated flame retardants are under discussion because of the formation of polybrominated dibenzo-p-dioxins (PBDD)\\/dibenzofurans (PBDF) (PBDD\\/F) in case of thermal stress. Concerning polymer linked tetrabromobisphenol A (TBBP A), formation of PBDD\\/F was commonly presumed to be sterically hindered because of the covalent fixation into the polymer backbone. Combustion experiments with additively incorporated TBBP A compared with

H. Wichmann; F. T. Dettmer; M. Bahadir

2002-01-01

74

A Survey of Low Temperature Polymers.  

National Technical Information Service (NTIS)

This paper presents a cursory survey of the literature on low temperature polymers. Emphasis was placed on thermoplastic as opposed to thermoset polymers. In an attempt to answer the primary question of what constitutes a good low temperature polymer, the...

K. B. Wischmann

1969-01-01

75

Hat-stiffened structures using commingled fabric thermoplastic composites  

NASA Astrophysics Data System (ADS)

The use of commingled fabrics is investigated as a possible way of solving problems that are commonly associated with the processing of thermoplastics. The advantages and disadvantages of commingled materials are examined with particular reference to results obtained for commingled yarns consisting of continuous carbon or glass reinforcement intimately blended with fine thermoplastic-polymer materials. Fabrication of hat-stiffened and flat panels produced by press molding, vacuum bagging, diaphragm molding, and autoclave processing is discussed, with attention given to detailed procedures, conditions, and resulting panel properties.

Olson, Steven H.

76

POLYMER ENGINEERING: The importance of heat transfer in polymer processing  

Microsoft Academic Search

Heat transfer plays a critical role in the processing of thermoplastic polymers, influencing capital costs, operating costs, production rates and product quality. Closer collaboration between scientists and engineers in this field would improve the efficiency of polymer processing operations

M. F. Edwards; D. I. Ellis

1982-01-01

77

Digital Applications of Thermoplastic Recording  

Microsoft Academic Search

Thermoplastic films' unique combination of thermal, electrical, and optical properties results in a versatile information storage medium which finds both digital and analog applications. As a digital storage medium, thermoplastic is best suited as a file memory where large capacity and rapid read access is a necessity. Reading and writing rates are completely independent. The fabrication of either sequential or

R. G. Reeves

1963-01-01

78

Thermoplastic Patient Fixation  

Microsoft Academic Search

\\u000a Background and Purpose:  Several methods have been developed to reduce tumor motions and patient movements during radiotherapy of lung cancer. In this\\u000a study, a multislice CT-based analysis was performed to examine the effect of a thermoplastic patient immobilization system\\u000a on the chest wall and tumor motions.\\u000a \\u000a \\u000a \\u000a Patients and Methods:  Ten patients with stage II–IV lung cancer were enrolled into the study. According

Arpad Kovacs; Janaki Hadjiev; Ferenc Lakosi; Marta Vallyon; Zsolt Cselik; Peter Bogner; Akos Horvath; Imre Repa

2007-01-01

79

Thermoplastic films from cyanoethylated chicken feathers  

Microsoft Academic Search

This paper demonstrates that etherification can be used to develop thermoplastic films from chicken feathers. Feathers are inexpensive, abundantly available and renewable resources but have limited applications mainly due to their non-thermoplasticity. However, it has been shown that chemical modifications such as grafting can make feathers thermoplastic. Etherification provides better thermoplasticity to biopolymers compared to chemical modifications such as acetylation.

Narendra Reddy; Chunyan Hu; Kelu Yan; Yiqi Yang

2011-01-01

80

A critical mass flux model for the flammability of thermoplastics  

NASA Astrophysics Data System (ADS)

The combustion of thermoplastics is modelled using a critical mass flux hypothesis as the ignition and extinction criteria. Polymer degradation is modelled as a single-step first-order Arrhenius reaction term. A simple model for mass transport of polymer through the sample during pyrolysis is included. The degradation products are assumed to move out of the polymer instantaneously. The model consists of a nonlinear integral-differential advection-diffusion equation for the temperature in the thermoplastic, coupled to an ordinary differential equation, for the regression rate. Results are presented which quantify the effect that the thickness of the test sample has on the mass-loss rate, or equivalently heat-release rate, curve. From these we conclude that thermally thick samples are characterized by a region of steady burning which is independent of the initial sample thickness. The test method that we have in mind is the cone calorimeter.

Staggs, J. E. J.; Nelson, M. I.

2001-09-01

81

The quality of fibre reinforced thermoplastics mouldings  

NASA Astrophysics Data System (ADS)

The requirement for injection molded short carbon fiber reinforced thermoplastics in helicopter applications is based on component coat and weight savings. The presence of short fibers in a thermoplastic polymer can exert a significant influence upon the rheological properties of the melt. As it is the rheology of the material which determines melt flow performance and hence the flow-induced fiber orientation in the final molded part, accurate data are required to understand and predict polymer flow. Although standard procedures exist for determining the rheological characteristics of melts, their relevance to the injection modling proscess was questioned. Consequently, a high shear rate rheometer was developed, and the results for the filled and unfilled melts compared with the standard equipment. Significant effects involving thermal conductivity and fiber breaking were identified which leads to errors in the data produced using the standard device. Two techniques using reflected light and thermal imaging were successfully developed for the characterization of the orientation of short carbon fibers in injection molded parts. Welds are a common feature in injection molded parts. This study also addresses the problem of the knit weld in a specially designed test specimen. Applying fracture mechanics principles, the integrity of the welded structure was analyzed, and the results correlated with microstructural observations. Finally, impact studied using subcomponent geometries have addressed the effects of flow induced fiber orientation in specific geometrical features.

Potts, Hugh Adrian

82

Characterization of a Thermoplastic Polyimidesulfone.  

National Technical Information Service (NTIS)

The detailed characterization of an experimental thermoplastic polyimidesulfone adhesive based on 3,3 prime-diaminodiphenylsulfone and 3,3 prime,4,4 prime-benzophenone tetracarboxylic dianhydride was studied. Model compounds were also examined. Thermal cy...

J. F. Dezern P. R. Young

1985-01-01

83

Thermoplastic Recording Materials for Holography.  

National Technical Information Service (NTIS)

Recording materials with photoconductive and thermoplastic layers for the registration of phase holograms were developed. After adaption of the sensitometric properties, the coating technology for the production of such materials was elaborated. Devices f...

R. Moraw

1977-01-01

84

Poly(urethane-imide-imide), a new generation of thermoplastic polyurethane elastomers with enhanced thermal stability  

Microsoft Academic Search

A new generation of polyurethane thermoplastic elastomers were synthesized via the reaction of NCO-terminated polyurethane with 2,2?-pyromellitdiimidodisuccinic anhydride chain extender. The starting materials and polymers were characterized by conventional methods and physical, mechanical and thermal properties were studied. In comparison to typical polyurethanes, these polymers exhibited improved thermal stability as well as good processability and flexibility.

Hamid Yeganeh; Mohammad Amin Shamekhi

2004-01-01

85

Effect of carbon black on light transmission in laser welding of thermoplastics  

Microsoft Academic Search

It is important to describe the laser energy transmission and absorption in polymers properly when modeling heat transfer in laser transmission welding (LTW) of thermoplastics. This paper uses the Bouguer–Lambert law and an apparent absorption coefficient to describe the total laser energy attenuation in scattering polymers with and without carbon black (CB). The model was validated using the measured transmittances

Mingliang Chen; Gene Zak; Philip J. Bates

2011-01-01

86

Synthesis and characterization of thermoplastic polyphenoxyquinoxalines  

NASA Astrophysics Data System (ADS)

This research was divided into two main parts. In the first part, a new facile route to relatively inexpensive thermoplastic polyphenoxyquinoxalines was developed. The synthetic route involves the aromatic nucleophilic substitution reaction of bisphenols with 2,3-dichloroquinoxaline. The dichloro monomer was prepared in two steps. In the first step, oxalic acid was condensed with o-phenylenediamine to give 2,3-dihydroxyquinoxaline. In the second step, 2,3-dihydroxyquinoxaline was treated with thionyl chloride to give 2,3-dichloroquinoxaline. This monomer was successfully polymerized with bisphenol-A, bisphenol-S, hexafluorobisphenol-A and 9,9-bis(4-hydroxyphenyl)fluorenone. Hydroquinone and biphenol, however, can not be polymerized to high molecular weight polymers because of the premature precipitation of crystalline oligomers. The glass transition temperatures of the high molecular weight polymers prepared from a series of bisphenols range from 191 °C to 279 °C, and their thermal decomposition temperatures are around 500 °C. The polymers are soluble in a wide range of solvents and can be solution-cast into thin films that are colorless and transparent. The polymers have tensile strengths ranging from 61 to 107 MPa, and tensile moduli ranging from 3.5 to 2.3 GPa. The synthesis of polymer obtained from 2,3-dichloroquinoxaline and bisphenol-A was scaled up to afford 500 g of material. This polymer is a thermoplastic with a melt-viscosity less than 1000 Pa.s. at 300 °C. The notched Izod impact strength of injection-molded samples of this polymer is 40.7 J/m. In the second part of this research, the synthetic method has been modified to allow the preparation of quinoxaline containing polyimides. Thus, 2,3-dichloroquinoxaline was treated either with p-nitrophenol followed by reduction of nitro groups, or with p-aminophenols to directly obtain the desired 2,3-(4-aminophenoxy)quinoxaline. This diamine was polymerized with 3,3',4,4'-biphenyldianhydride, 4,4'-oxydiphthalic anhydride and 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride. The polymerizations were carried out by the two step method. The poly(amic acid) intermediates were thermally imidized. Although they have high molecular weights judged by their inherent viscosities ranging from 0.51 to 1.01, thin films of all these polyimides were brittle. The glass transition temperatures of the polyimides range from 259 °C to 282 °C with thermal decomposition temperatures around 550 °C. The polyimide obtained from 2,3-(4-aminophenoxy)quinoxaline and 3,3',4,4'-biphenyldianhydride was found to be semi-crystalline.

Erdem, Haci Bayram

87

Thermoplastic starch films with vegetable oils of Brazilian Cerrado  

Microsoft Academic Search

Starch is one of the most promising natural polymers to be abundant, cheap and biodegradable. To get thermoplastic starch\\u000a (TPS) is necessary mechanical shake, high temperature and use of plasticizers. In this work, TPS films were prepared by casting\\u000a from cassava starch and three different vegetable oils of Brazilian Cerrado as plasticizer: buriti, macauba and pequi. The\\u000a materials were analyzed

Daniela Schlemmer; Maria José Araujo Sales

2010-01-01

88

Biosynthesis of novel thermoplastic polythioesters by engineered Escherichia coli  

Microsoft Academic Search

The development of non-petrochemical sources for the plastics industry continues to progress as large multinationals focus on renewable resources to replace fossil carbon. Many bacteria are known to accumulate polyoxoesters as water-insoluble granules in the cytoplasm. The thermoplastic and\\/or elastomeric behaviour of these biodegradable polymers holds promise for the development of various technological applications. Here, we report the synthesis and

Tina Lütke-Eversloh; Andreas Fischer; Uwe Remminghorst; Jumpei Kawada; Robert H. Marchessault; Ansgar Bögershausen; Martin Kalwei; Hellmut Eckert; Rudolf Reichelt; Shuang-Jiang Liu; Alexander Steinbüchel

2002-01-01

89

Thermoplastic tape compaction device  

DOEpatents

A device for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite.

Campbell, Vincent W. (Oak Ridge, TN)

1994-01-01

90

High-pressure on-chip mechanical valves for thermoplastic microfluidic devices.  

PubMed

A facile method enabling the integration of elastomeric valves into rigid thermoplastic microfluidic chips is described. The valves employ discrete plugs of elastomeric polydimethylsiloxane (PDMS) integrated into the thermoplastic substrate and actuated using a threaded stainless steel needle. The fabrication process takes advantage of poly(ethylene glycol) (PEG) as a sacrificial molding material to isolate the PDMS regions from the thermoplastic flow channels, while yielding smooth contact surfaces with the PDMS valve seats. The valves introduce minimal dead volumes, and provide a simple mechanical means to achieve reproducible proportional valving within thermoplastic microfluidic systems. Burst pressure tests reveal that the valves can withstand pressures above 12 MPa over repeated open/close cycles without leakage, and above 24 MPa during a single use, making the technology well suited for applications such as high performance liquid chromatography. Proportional valve operation is demonstrated using a multi-valve chemical gradient generator fabricated in cyclic olefin polymer. PMID:20024030

Chen, Chien-Fu; Liu, Jikun; Chang, Chien-Cheng; DeVoe, Don L

2009-10-06

91

A review of recent developments in joining high-performance thermoplastic composites  

NASA Astrophysics Data System (ADS)

There is currently a great deal of interest in the use of thermoplastic polymers as matrices in fiber reinforced composites for high performance applications, such as those encountered in the aerospace industry. These materials include polyether ether ketone (PEEK), polyphenylene sulphide (PPS), polyetherimide (PEI), polyamideimide (PAI), polyamides, polyimides, and polysulphones. A literature review is provided on the different ways of joining high performance thermoplastic composites by adhesive and fusion bonding. The discussion on adhesive bonding includes examination of the performance of specific adhesive/thermoplastic combinations and of techniques for the preparation of composite surfaces: abrasion, etching, flame, and plasma treatments. Thermoplastic composite welding techniques discussed in depth include the following: heated press welding, resistance welding, induction welding, and ultrasonic welding. Works which examine or compare applications for these bonding techniques are also reviewed.

Cole, K. C.

1991-06-01

92

Structure and thermoplasticity of coal  

SciTech Connect

Chapters cover: molecular structure and thermoplastic properties of coal; {sup 1}H-nmr study of relaxation mechanisms of coal aggregate; structural changes of coal macromolecules during softening; quantitative estimation of metaplsat in heat-treated coal by solvent extraction; effects of surface oxidation on thermoplastic properties of coal; analysis of dilatation and contraction of coal during carbonization; formation mechanisms of coke texture during resolidification; modified CPD model for coal devolatilization; mathematical modelling of coke mechanical structure; and simulating particulate dynamics in the carbonization process based on discrete element treatment.

Komaki, I.; Itagaki, S.; Miura, T. (eds.)

2004-07-01

93

Effects of thermoplastic resin content of anisotropic conductive films on the pressure cooker test reliability of anisotropic conductive film flip-chip assembly  

NASA Astrophysics Data System (ADS)

The flip-chip technology using anisotropic conductive films (ACFs) is gaining growing interest due to its technical advantages such as environmentally friendly, simpler, and lower cost processes. Electrical performances and reliability of ACF flip-chip assembly depend on thermomechanical properties of ACF polymer resins. In this paper, the changes in ACF resin morphology due to the phase separation of thermoplastics, and subsequent changes of physical and mechanical properties were investigated as a function of thermoplastic contents of ACF formulation. Furthermore, the pressure cooker test (PCT) reliability of ACF flip-chip assemblies with various thermoplastic contents was also investigated. As thermoplastic contents increased, coefficient of thermal expansion (CTE) of ACFs increased, and elastic modulus (E?) of ACFs decreased. In contrast, water absorption rate decreased as thermoplastic content increased. As a result, PCT reliability of ACF flip-chip assembly was improved adding up to 50 wt.% content of thermoplastic.

Hwang, J. W.; Yim, M. J.; Paik, K. W.

2005-11-01

94

Thermal residual stresses in amorphous thermoplastic polymers  

NASA Astrophysics Data System (ADS)

An attempt to calculate the internal stresses in a cylindrically shaped polycarbonate (LEXAN-GE) component, subjected to an arbitrary cooling rate, will be described. The differential volume relaxation arising as a result of the different thermal history suffered by each body point was considered as the primary source of stresses build up [1-3]. A numerical routine was developed accounting for the simultaneous stress and structural relaxation processes and implemented within an Ansys® environment. The volume relaxation kinetics was modeled by coupling the KAHR (Kovacs, Aklonis, Hutchinson, Ramos) phenomenological theory [4] with the linear viscoelastic theory [5-7]. The numerical algorithm translates the specific volume theoretical predictions at each body point as applied non-mechanical loads acting on the component. The viscoelastic functions were obtained from two simple experimental data, namely the linear viscoelastic response in shear and the PVT (pressure volume temperature) behavior. The dimensionless bulk compliance was extracted from PVT data since it coincides with the memory function appearing in the KAHR phenomenological theory [7]. It is showed that the residual stress scales linearly with the logarithm of the Biot's number.

Grassia, Luigi; D'Amore, Alberto

2010-06-01

95

Heat recovery in thermoplastics production  

Microsoft Academic Search

An energy optimization of production of a thermoplastic material, polyamid-6, i.e. nylon-6, using boiler flue gases heat recovery is presented. Energy and environmental studies show an increase of process efficiency simultaneously with a decrease of thermal pollution. If the feed water is heated with flue gases, the fuel consumption is reduced by about 13%, while the boiler outlet flue gases

Alka Miheli?-Bogdani?; Rajka Budin

2002-01-01

96

Coating plywood with a thermoplastic  

Microsoft Academic Search

This work presents a method for the surfacing of wood sheets such as plywood with melt processable thermoplastic using extrusion coating. The method uses a direct coating of the plywood with a very hot low-viscosity coating. During the coating, the pressure of the melt is kept as low as possible. These factors produce a very high mechanical adhesion between the

Pentti K. Järvelä; Outi Tervala; Pirkko A. Järvelä

1999-01-01

97

Non Destructive Testing of Thermoplastic Composites by NMR Imaging and Localised Spectroscopy  

Microsoft Academic Search

The application of NMR methods to the non-destructive testing of thermoplastic composites is discussed. NMR imaging of the polymer matrix is restricted to the detection of defects in excess of 5 mm using standard instrumentation. Higher resolution can be achieved by imaging the matrix at high temperatures or by more sophisticated NMR procedures with the practical limit of 0.1 mm

Nigel J. Clayden; Peter Jackson

1994-01-01

98

An investigation into welding of engineering thermoplastics using focused microwave energy  

Microsoft Academic Search

Microwaves have been used for many years in industrial heating applications because of their ability to heat materials volumetrically. The dielectric properties of a material determine its ability to absorb microwave radiation. In this paper, the dielectric properties of engineering thermoplastic materials, which include ultra high molecular weight polyethylene (UHMW PE), polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) polymers under room temperature

Prasad K. D. V Yarlagadda; Tan Chuan Chai

1998-01-01

99

Thermoplastic sandwich structure design and manufacturing for the body panel of mass transit vehicle  

Microsoft Academic Search

Weight savings in vehicles enhances fuel efficiency and decreases maintenance costs, especially in mass transit systems. Lightweight composite materials, such as glass fiber reinforced polymers, have been used to replace traditional steel and aluminum components. In this paper, a mass transit bus side body panel was designed, analyzed, and manufactured using thermoplastic composite materials. The design featured a sandwich composite

Haibin Ning; Gregg M. Janowski; Uday K. Vaidya; George Husman

2007-01-01

100

Water Desorption Kinetics of Polymer Composites with Cellulose Fibers as Filler  

Microsoft Academic Search

The water desorption kinetics of polymer composite systems with hydrophilic cellulose fibers from recycled paper (PSP) filler embedded in various polymer matrices (hydrophobic thermoset epoxy resin [EP] and thermoplastic polypropylene [PP], and hydrophilic thermoplastic poly[vinyl alcohol] [PVA]) was studied. Polymer composites test pieces containing 0, 3, 6, 9, and 30 wt. % of fibers were prepared. Adhesion between fibers and

Dora Kroisová; Petr Špatenka

2009-01-01

101

Multiphase design of autonomic self-healing thermoplastic elastomers  

NASA Astrophysics Data System (ADS)

The development of polymers that can spontaneously repair themselves after mechanical damage would significantly improve the safety, lifetime, energy efficiency and environmental impact of man-made materials. Most approaches to self-healing materials require the input of external energy, healing agents, solvent or plasticizer. Despite intense research in this area, the synthesis of a stiff material with intrinsic self-healing ability remains a key challenge. Here, we show a design of multiphase supramolecular thermoplastic elastomers that combine high modulus and toughness with spontaneous healing capability. The designed hydrogen-bonding brush polymers self-assemble into a hard-soft microphase-separated system, combining the enhanced stiffness and toughness of nanocomposites with the self-healing capability of dynamic supramolecular assemblies. In contrast to previous self-healing polymers, this new system spontaneously self-heals as a single-component solid material at ambient conditions, without the need for any external stimulus, healing agent, plasticizer or solvent.

Chen, Yulin; Kushner, Aaron M.; Williams, Gregory A.; Guan, Zhibin

2012-06-01

102

Mesoporous carbon nanofibers with a high surface area electrospun from thermoplastic polyvinylpyrrolidone  

NASA Astrophysics Data System (ADS)

Carbon nanofibers (CNFs) have been synthesized from thermoplastic polyvinylpyrrolidone (PVP) using electrospinning in combination with a novel three-step heat treatment process, which successfully stabilizes the fibrous morphology before carbonization that was proven to be difficult for thermoplastic polymers other than polyacrylonitrile (PAN). These CNFs are both mesoporous and microporous with high surface areas without subsequent activation, and thus overcome the limitations of PAN based CNFs, and are processed in an environmentally friendly and more cost effective manner. The effects of heat treatment parameters and precursor concentration on the morphologies and porous properties of CNFs have been investigated, and their application as anodes for lithium ion batteries has also been demonstrated.

Wang, Peiqi; Zhang, Dan; Ma, Feiyue; Ou, Yun; Chen, Qian Nataly; Xie, Shuhong; Li, Jiangyu

2012-10-01

103

TECHNOLOGY, APPLICABILITY, AND FUTURE OF THERMOPLASTIC TIMBER  

Microsoft Academic Search

This paper describes a new generation of innovative structural products made from 100% recycled consumer and industrial plastics called Thermoplastic timber. Developed by scientists at Rutgers University and tested by the US Army Corps of Engineers, the patented technologies provide products that are extremely strong and durable, flexible in design, and virtually maintenance-free. Successful demonstrations have shown that Thermoplastic timber

Lisa Miles Jackson

104

Liquid Molding of Fabric Reinforced Thermoplastic Composites  

Microsoft Academic Search

The present work addresses the thermal, static, and dynamic mechanical properties of carbon fabric- reinforced, thermoplastic polyamide 6 (also referred to as nylon 6 and\\/or PA6) matrix panels processed using vac- uum assisted resin transfer molding (VARTM). Liquid molding of thermoplastics has been limited by high resin viscosity, high temperature processing requirements, and a short processing window. The processing parameters

Selvum Pillay; Uday Vaidya; Gregg M. Janowski

105

Development of ecofriendly thermoplastics for automotive components  

Microsoft Academic Search

Use of natural fiber thermoplastic components in the automotive industry can provide the advantages of weight reduction, cost reduction and recyclability, in addition to eco-efficiency and renewability compared to synthetic conventional materials. Natural fibers have recently become attractive to automotive industry as an alternative reinforcement for glass fiber reinforced thermoplastics. The best way to increase the fuel efficiency with out

S. Jeyanthi; M. Purushothaman; J. Janci Rani

2011-01-01

106

Thermoplastic pultrusion of natural fibre reinforced composites  

Microsoft Academic Search

Thanks to the good mechanical properties and the ecological and environmental advantages, the natural fibre flax offers good opportunities as a reinforcement material for composites, especially thermoplastic ones. One technique for the manufacture of composites on a continuous basis is pultrusion. This paper describes the possibility of the use of flax as reinforcement in thermoplastic pultruded composites.

Kathleen Van de Velde; Paul Kiekens

2001-01-01

107

Sterilizing radiation effects on selected polymers  

SciTech Connect

The mechanism of radiation effects and their industrial applications are discussed for the following classes of polymers: thermoplastics, thermosets, elastomers, films and fibers, and adhesives/coatings/potting compounds. 35 references, 3 tables. (DLC)

Skiens, W. E.

1979-03-01

108

Study on the Functionality of Nano-Precipitated Calcium Carbonate as Filler in Thermoplastics  

NASA Astrophysics Data System (ADS)

This research aims to investigate the functionality of nano-precipitated calcium carbonate (NPCC) as filler in thermoplastic resins based on property enhancement. Three types of thermoplastics were used: polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC). The resins were evaluated by determining the effect of different NPCC loading on the chemical structure, thermal and mechanical properties of thermoplastics. Results showed that there was an interfacial bonding with the NPCC surface and the thermoplastics. Change in absorption peak and area were predominant in the PVC filled composite. There was a decreased in crystallinity of the PE and PP with the addition of filler. Tremendous increase on the tensile and impact strength was exhibited by the NPCC filled PVC composites while PE and PP composites maintained a slight increase in their mechanical properties. Nano-sized filler was proven to improve the mechanical properties of thermoplastics compared with micron-sized filler because nano-sized filler has larger interfacial area between the filler and the polymer matrix.

Basilia, Blessie A.; Panganiban, Marian Elaine G.; Collado, Archilles Allen V. C.; Pesigan, Michael Oliver D.; de Yro, Persia Ada

109

Joining of thermoplastic substrates by microwaves  

DOEpatents

A method for joining two or more items having surfaces of thermoplastic material includes the steps of depositing an electrically-conductive material upon the thermoplastic surface of at least one of the items, and then placing the other of the two items adjacent the one item so that the deposited material is in intimate contact with the surfaces of both the one and the other items. The deposited material and the thermoplastic surfaces contacted thereby are then exposed to microwave radiation so that the thermoplastic surfaces in contact with the deposited material melt, and then pressure is applied to the two items so that the melted thermoplastic surfaces fuse to one another. Upon discontinuance of the exposure to the microwave energy, and after permitting the thermoplastic surfaces to cool from the melted condition, the two items are joined together by the fused thermoplastic surfaces. The deposited material has a thickness which is preferably no greater than a skin depth, .delta..sub.s, which is related to the frequency of the microwave radiation and characteristics of the deposited material in accordance with an equation.

Paulauskas, Felix L. (Oak Ridge, TN); Meek, Thomas T. (Knoxville, TN)

1997-01-01

110

Rapid, controllable and environmentally benign fabrication of thermoplastic nanofibers and applications  

NASA Astrophysics Data System (ADS)

In situ fibrillar and lamellar hybrid morphology was found in various immiscible polymer blends prepared by melt ram extrusion of cellulose acetate butyrate (CAB)/Thermoplastics at a weight ratio of 80 to 20. The formation process was analyzed and proposed. The presence of the elongational flow field determines the formation of the fibrils, and the improvement of the mixing efficiency can significantly reduce the dimensions of formed fibrils into the submicro- or nano-scale. With above results, continuous and uniform yarns of thermoplastic nanofibers were prepared via direct melt twin-screw extrusion, providing better mixing efficiency of immiscible blends of thermoplastic polymers with cellulose acetate butyrate (CAB), and subsequent extraction removal of CAB matrix. The thermoplastics which can be made into nanofibers include polyesters, polyolefins, thermoplastic polyurethane and functional copolymers, such as PE-co-GMA (Poly(Ethylene-co-Glycidyl Methacrylate)), PVA-co-PE (Poly(Vinyl Alcohol-co-Ethylene)). Ratios of thermoplastics to sacrificial CAB matrix, melt viscosity, and interfacial tensions affect formation of the nanofibers. Moreover, the crystal structures of isotactic polypropylene (iPP) nanofiber prepared were characterized with DSC and WAXD. To further demonstrate the size and shape controllability of the thermoplastic nanomaterials, polyethylene materials were selected and prepared into micro- or submicrospheres or nanofibers with different diameters and shapes by varying the composition ratio and modifying the interface properties via melt blending or extrusion of cellulose acetate butyrate (CAB)/LDPE melt blends and subsequent removal of the CAB. The surface structures of the LDPE micro- or submicrospheres and nanofibers were analyzed using SEM, FTIR-ATR spectroscopy, DSC and torque rheometer. The biotechnological applications of the thermoplastic nanofibers are also exploited. Poly(ethylene-co-glycidyl methacrylate) (PE-co-GMA) nanofibers with abundant active epoxy groups on surfaces were fabricated through above technique. The prepared PE-co-GMA nanofibers were aminated by reacting the epoxy groups with 1,3-diaminopropane. The resulting aminated PE-co-GMA nanofibers were subsequently biotinylated and then successfully applied to immobilize streptavidin-horseradish peroxidase (HRP) conjugate via specific, strong and rapid binding of biotin and streptavidin. The high activity, efficiency, sensitivity as well as good reusability of the streptavidin-HRP immobilized PE-co-GMA nanofibers demonstrated that PE-co-GMA nanofibers could be a promising candidate as solid support materials for potential biosensor applications.

Wang, Dong

111

Polymer alloys with balanced heat storage capacity and engineering attributes and applications thereof  

Microsoft Academic Search

A thermoplastic polymer of relatively low melt temperature is blended with at least one of thermosets, elastomers, and thermoplastics of relatively high melt temperature in order to produce a polymer blend which absorbs relatively high quantities of latent heat without melting or major loss of physical and mechanical characteristics as temperature is raised above the melting temperature of the low-melt-temperature

Soroushian; Parviz

2002-01-01

112

Characterization of Powder Coated Thermoplastic Composite.  

National Technical Information Service (NTIS)

Thermoplastic powder resin preforms are a relatively new form of composite preform material. Powder preforms offer improved handelability as well as the possibility to produce composites from resins that are difficult to prepreg. The purpose of this proje...

R. Cochran

1991-01-01

113

Reactive Plasticizers for High Temperature Quinoxaline Thermoplastics.  

National Technical Information Service (NTIS)

This report is concerned with a novel approach to the processing of high temperature thermoplastics. A series of bis(ethynylquinoxaline) monomers were prepared to demonstrate the feasibility of using reactive plasticizers in the processing of polyphenylqu...

R. F. Kovar G. F. L. Ehlers F. E. Arnold

1976-01-01

114

Characterization of Polyetheretherketone and Other Engineering Thermoplastics.  

National Technical Information Service (NTIS)

Three engineering thermoplastic materials were characterized by thermal/spectroscopic means to assess their suitability in fiberglass-filled molding resins for Mound applications. The three resins examined were: polyetheretherketone (PEEK) from ICI, Ltd.,...

R. B. Whitaker A. B. Nease R. O. Yelton

1984-01-01

115

Improved thermoplastic materials for offshore flexible pipes  

SciTech Connect

Long-term aging tests representative of field operating conditions have been conducted on various thermoplastic materials proposed for the inner tube of flexible pipes for offshore drilling and production applications. In particular, experimental data are provided about the changes of the mechanical properties of selected thermoplastic materials owing to optimized formulation when the pipes are exposed over time to crude oil in the presence of gas and water.

Dawans, F.; Jarrin, J.; Hardy, J.

1988-08-01

116

Formation of aromatic thermoplastic and carbon-fiber prepreg by electrochemical processes  

SciTech Connect

A new technique was developed and demonstrated for combining carbon fibers with aromatic thermoplastic matrices to form a high-quality towpreg. The developed technique utilizes an in-situ electrochemical process (Electrochemical polymerization - ECP) to create the entire polymer matrix surrounding the fiber array by direct polymerization of monomer. Poly-paraxylylene (PPX) and derivatives are successfully polymerized in-situ on carbon fiber surfaces through ECP. A PPX/carbon-fiber towpreg with 40 vol % of matrix is achieved in a fairly short reaction time with a high polymer-coating efficiency. Vapor deposition polymerization (VDP) was also studied. PPX and carbon-fiber towpreg were made successfully by this process. A comparison between ECP and VDP was conducted. A study on electrochemical oxidation (ECO) of carbon fibers was also performed. The ECO treatment may be suitable for carbon fibers incorporated in composites with high-temperature curing resins and thermoplastic matrices.

Li Hong.

1991-01-01

117

Reactive polymers: a route to nanoimprint lithography at low temperatures  

Microsoft Academic Search

To utilize the potential of nanoimprint lithography (NIL) you need polymers, which give relief patterns with good thermal and etch resistance, a necessity for subsequent process steps. Thermoplastic polymers with high thermal stability require high imprint temperatures. Such temperatures can cause polymer degradation and problems with pattern transfer due to the different coefficients of thermal expansion of substrate, polymer and

Karl Pfeiffer; Freimut Reuther; Patrick Carlberg; Marion Fink; Gabi Gruetzner; Lars Montelius

2003-01-01

118

Determination of metal additives and bromine in recycled thermoplasts from electronic waste by TXRF analysis  

Microsoft Academic Search

A new method for analysis of metal additives in recycled thermoplasts from electronic waste was developed, based on dissolving\\u000a the samples in an organic solvent and subsequent analysis of the corresponding solutions or suspensions by total-reflection\\u000a X-ray fluorescence spectroscopy (TXRF). The procedure proved to be considerably less time consuming than the conventional\\u000a digestion of the polymer matrix. Additives containing Ti,

H. Fink; U. Panne; M. Theisen; R. Niessner; T. Probst; X. Lin

2000-01-01

119

Degradation Studies of Thermoplastics Composites of Jute Fiber–Reinforced LDPE\\/Polycaprolactone Blends  

Microsoft Academic Search

This article reports the fabrication, properties, and degradation studies of jute fiber–reinforced thermoplastic polymers. One of the non-traditional outlets of jute fiber is in the area of fiber-reinforced composites. However, the major drawback associated with the application of jute fiber for this purpose is its high moisture regain. To impart hydrophobicity to the fibers and to concomitantly increase interfacial bond

Sandeep Kumar; Indra K. Varma

2006-01-01

120

Miscibility and Phase Behavior in Melt Blends of Thermoplastic Polyurethane and Styrene Acrylonitrile Copolymers  

Microsoft Academic Search

Phase behavior of the binary polymer system consisting of thermoplastic polyurethane (TPU) and styrene acrylonitrile (SAN) copolymers of various compositions (100\\/0, 90\\/10, 70\\/30, 50\\/50, 30\\/70, 0\\/100) has been investigated by differential scanning calorimeter (DSC). The phase separation on heating, i.e., lower critical solution temperature (LCST) behavior, was found to occur when these blends were heated to elevated temperatures. The cloud?point

S. N. Jaisankar; Y. Lakshminarayana; Ganga Radhakrishnan

2005-01-01

121

Multicomponent polymer materials  

SciTech Connect

Interpenetrating polymer networks are discussed, taking into account interpenetrating polymer networks based on polybutadiene and polystyrene, polyurethane-polysiloxane simultaneous interpenetrating polymer networks, extraction studies and morphology of physical-chemical interpenetrating polymer networks based on block polymer and polystyrene, twoand three-component interpenetrating polymer networks, and poly(acrylourethane)-polyepoxide semiinterpenetrating networks formed by electron-beam curing. Other topics studied are related to the characterization of polymer blends, the characterization of block copolymers, the mechanical behavior, and rheology and applications. Attention is given to a new silicone flame-retardant system for thermoplastics, recent developments in interpenetrating polymer networks and related materials, miscibility in random copolymer blends, crystallization and melting in compatible polymer blends, and fatigue in rubber-modified epoxies and other polyblends.

Paul, D.R.; Sperling, L.H.

1986-01-01

122

Effect of Nickel-Cobalt-Zinc Ferrite Filler on Electrical and Mechanical Properties of Thermoplastic Natural Rubber Composites  

Microsoft Academic Search

Thermoplastic natural rubber (TPNR) as polymer matrix was prepared by the melt blending method. Nickel-cobalt-zinc (NiCoZn) ferrite as a filler was prepared by the double-stage sintering method in air. The filler was incorporated in the polymer matrix using a Brabender internal mixer. The filler content was varied from 0 to 30 wt.%. The morphological study of the fractured surface using a

Dwi Puryanti; Sahrim Hj Ahmad; Mustaffa Hj Abdullah

2006-01-01

123

Development of Lignin-Based Polyurethane Thermoplastics  

SciTech Connect

In our continued effort to develop value-added thermoplastics from lignin, here we report utilizing a tailored feedstock to synthesize mechanically robust thermoplastic polyurethanes at very high lignin contents (75 65 wt %). The molecular weight and glass transition temperature (Tg) of lignin were altered through cross-linking with formaldehyde. The cross-linked lignin was coupled with diisocyanate-based telechelic polybutadiene as a network-forming soft segment. The appearance of two Tg s, around 35 and 154 C, for the polyurethanes indicates the existence of two-phase morphology, a characteristic of thermoplastic copolymers. A calculated Flory-Huggins interaction parameter of 7.71 also suggests phase immiscibility in the synthesized lignin polyurethanes. An increase in lignin loading increased the modulus, and an increase in crosslink-density increased the modulus in the rubbery plateau region of the thermoplastic. This path for synthesis of novel lignin-based polyurethane thermoplastics provides a design tool for high performance lignin-based biopolymers.

Saito, Tomonori [ORNL] [ORNL; Perkins, Joshua H [ORNL] [ORNL; Jackson, Daniel C [ORNL] [ORNL; Trammell, Neil E [ORNL] [ORNL; Hunt, Marcus A [ORNL] [ORNL; Naskar, Amit K [ORNL] [ORNL

2013-01-01

124

Microcellular Foams Based on High Performance Thermoplastic Nanocomposites  

SciTech Connect

Foams from engineering thermoplastics nanocomposites based on Polyethersulphone and Polyethylene-2,6-naphthalate were prepared by using two different nanofillers (Silica nanoparticles and Graphite nanosheets). The effects of the nanofiller type and content on the foaming process was investigated and related to the density and cellular morphology of foams. The nanocomposite foams based on PES matrix exhibited improved nucleated cells both with SiO{sub 2} and Graphite nanosheets, but the density increased at all temperatures. On the contrary, nanocomposite foams based on PEN matrix showed different behaviors with the filler type. In this case, in fact, silica nanoparticles allowed lower densities when compared to the unfilled polymer foams, without influencing cells density. The Graphite nanosheets extended towards higher temperatures the foaming window of PEN nanocomposites, allowing densities as low as 0.15 at 260 deg. C.

Sorrentino, Luigi; Iannace, Salvatore [Institute for Composite and Biomedical Materials-National Research Council Piazzale V. Tecchio, 80-80125 Napoli (Italy)] [IMAST-Technological District in Polymer and Composite Engineering P.le Fermi 1 80055 Portici (Italy); Gargiulo, Marcella [Institute for Composite and Biomedical Materials-National Research Council Piazzale V. Tecchio, 80-80125 Napoli (Italy); Pezzullo, Giuseppe [Department of Materials and Production Engineering-University of Napoli Federico II Piazzale V. Tecchio, 80-80125 Napoli (Italy)

2010-06-02

125

Thermoplastic Elastomers via polyolefin/Layered Silicate Nanocomposites  

NASA Astrophysics Data System (ADS)

Here we report the synthesis of fully exfoliated polyolefin nanocomposites via Surface-Initiated Ring Opening Metathesis Polymerization (SI-ROMP). Montmorillonite (MMT) clay platelets were rendered hydrophobic through ion exchange with alkyl-ammonium surfactants terminated with norbornene. We were then able to form block copolymer brushes of (substituted) norbornenes and cyclopentene via SI-ROMP. Subsequent hydrogenation yielded highly crystalline polyethylene and rubbery saturated polynorbornenes, thus giving a thermoplastic elastomer. Nanocomposites were prepared with different nanofiller percentages and were characterized for morphological (XRD, TEM), thermal (TGA, DSC), and mechanical (DMA, Rheology) properties. Complete exfoliation of nanocomposites was confirmed by XRD and TEM. A fraction of the polymer brushes were subsequently removed from their substrate by reverse ion exchange and characterized in parallel with their corresponding nanocomposite analogs. In this way we were able to directly assess the role of the filler particle in the thermal properties, melt rheology, morphology, and tensile properties.

Harsha Kalluru, Sri; Cochran, Eric W.

2013-03-01

126

Thermally Conductive Polymer Matrix Composites  

Microsoft Academic Search

\\u000a Thermally conductive polymer matrix composites are used increasingly for thermal management of electronic packaging system.\\u000a The polymer matrix includes both thermosetting and thermoplastic types. Different kinds of fillers or reinforcements have\\u000a been developed to process composite materials with desired thermal, mechanical, and electrical properties. Reinforcement fillers\\u000a have an important role to play in maximizing polymer performance and production efficiency. Cost

Xingcun Colin Tong

127

Modelling of the Indentation Behaviour of Thermoplastic Honeycomb Sandwich Panels  

Microsoft Academic Search

Thermoplastic honeycombs based on polypropylene are one of the latest types of cores used in sand- wich structures. Up to now there have been few experimental and modelling studies on the mechani- cal behaviour of sandwich structures with thermoplastic cores. In this paper, by considering the sim- ilar properties of foams and thermoplastic honeycombs, attempts are made to model the

V. Khalili Moghamir; H. Rahimi; M. H. R. Ghoreishy; A. M. Rezadoust; M. Esfandeh

2008-01-01

128

Plastic wastes as modifiers of the thermoplasticity of coal  

SciTech Connect

Plastic waste recycling represents a major challenge in environmental protection with different routes now available for dealing with mechanical, chemical, and energy recycling. New concepts in plastic waste recycling have emerged so that now such wastes can be used to replace fossil fuels, either as an energy source or as a secondary raw material. Our objective is to explore the modification of the thermoplastic properties of coal in order to assess the possibility of adding plastic waste to coal for the production of metallurgical coke. Two bituminous coals of different rank and thermoplastic properties were used as a base component of blends with plastic wastes such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), poly(ethylene terephthalate) (PET), and acrilonitrile-butadiene-styrene copolymer (ABS). In all cases, the addition of plastic waste led to a reduction in Gieseler maximum fluidity, the extent of the reduction depending on the fluidity of the base coal, and the amount, the molecular structure, and the thermal behavior of the polymer. As a consequence, the amount of volatile matter released by the plastic waste before, during, and after the maximum fluidity of the coal and the hydrogen-donor and hydrogen-acceptor capacities of the polymer were concluded to be key factors in influencing the extent of the reduction in fluidity and the development of anisotropic carbons. The incorporation of the plastic to the carbon matrix was clearly established in semicokes produced from blends of a high-fluid coal and the plastic tested by SEM examination. 42 refs., 10 figs., 7 tabs.

M.A. Diez; C. Barriocanal; R. Alvarez [Instituto Nacional del Carbon (INCAR), Oviedo (Spain)

2005-12-01

129

Acetylation of chicken feathers for thermoplastic applications.  

PubMed

Poultry feathers are renewable resources, inexpensive and abundantly available, but have limited applications. Although keratin extracted from feathers has been chemically modified, there are no reports on the chemical modification or development of thermoplastics from poultry feathers. Acetylation is an inexpensive and environmentally friendly approach to make biopolymers thermoplastic. Several biopolymers have been acetylated and used to produce fibers, films, and extrudates. In this research, chicken feathers were acetylated, and the structure and properties of the acetylated feathers were studied. Acetylation conditions such as concentration of chemicals and catalyst and time and temperature of acetylation were optimized. Acetylation of feathers was confirmed using Fourier transform infrared (FTIR) and pyrolysis-gas chromatography-mass spectrometry (P-GC-MS). The acetylated feathers were analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to understand their thermal behavior. Acetylated feathers were thermoplastic and could be compression molded to form transparent films despite the relatively low percentage of acetyl content. PMID:21882886

Hu, Chunyan; Reddy, Narendra; Yan, Kelu; Yang, Yiqi

2011-09-14

130

Multiphase design of autonomic self-healing thermoplastic elastomers.  

PubMed

The development of polymers that can spontaneously repair themselves after mechanical damage would significantly improve the safety, lifetime, energy efficiency and environmental impact of man-made materials. Most approaches to self-healing materials require the input of external energy, healing agents, solvent or plasticizer. Despite intense research in this area, the synthesis of a stiff material with intrinsic self-healing ability remains a key challenge. Here, we show a design of multiphase supramolecular thermoplastic elastomers that combine high modulus and toughness with spontaneous healing capability. The designed hydrogen-bonding brush polymers self-assemble into a hard-soft microphase-separated system, combining the enhanced stiffness and toughness of nanocomposites with the self-healing capability of dynamic supramolecular assemblies. In contrast to previous self-healing polymers, this new system spontaneously self-heals as a single-component solid material at ambient conditions, without the need for any external stimulus, healing agent, plasticizer or solvent. PMID:22614381

Chen, Yulin; Kushner, Aaron M; Williams, Gregory A; Guan, Zhibin

2012-04-01

131

Polyurethane thermoplastic elastomers with inherent radiopacity for biomedical applications.  

PubMed

Synthesis and characterization of three different radiopaque thermoplastic polyurethane elastomers are reported. Radiopacity was introduced to the polyurethanes by incorporating an iodinated chain extender, namely, 4,4'-isopropylidinedi-(2,6-diiodophenol) (IBPA), into the polymer chain during polyurethane synthesis. Radiopaque polyurethanes (RPUs) were synthesized by reacting 4,4'-methylenebis(phenyl isocyanate) (MDI), IBPA, and three different diols. The polyols used for the synthesis were polypropylene glycol, polycaprolactone diol, and poly(hexamethylene carbonate) diol. RPUs were characterized by infrared spectroscopy, contact angle measurements, thermogravimetry, dynamic mechanical analysis, energy dispersive X-ray analysis, gel permeation chromatography, X-ray fluorescence spectroscopy, and X-radiography. X-ray images showed that all RPUs prepared using IBPA as the chain extender are highly radiopaque compared with an Aluminum wedge of equivalent thickness. Elemental analysis revealed that the polyurethanes contained 18-19% iodine in the polymer matrix. The RPUs developed have radiopacity equivalent to that of a polymer filled with 20 wt % barium sulfate. Results revealed that RPUs of wide range of properties may be produced by incorporating different diols as the soft chain segment. Cell culture cytotoxicity studies conducted using L929 cells by direct contact test and MTT assay proved that these RPUs are noncytotoxic in nature. PMID:22815186

Kiran, S; James, Nirmala R; Jayakrishnan, A; Joseph, Roy

2012-07-20

132

Polymers  

NSDL National Science Digital Library

This page contains two documents explaining ring and cross link polymers. The topic is covered at an advanced level in relation to nanotechnology and requires background knowledge in eight grade science. A powerpoint with illustrations and instructor guide (available as both a Microsoft Word Document and PDF) containing activities are included to aid in teaching this subject.

2012-10-16

133

Electromechanical instabilities of thermoplastics: Theory and in situ observation  

PubMed Central

Thermoplastics under voltages are used in diverse applications ranging from insulating cables to organic capacitors. Electromechanical instabilities have been proposed as a mechanism that causes electrical breakdown of thermoplastics. However, existing experiments cannot provide direct observations of the instability process, and existing theories for the instabilities generally assume thermoplastics are mechanically unconstrained. Here, we report in situ observations of electromechanical instabilities in various thermoplastics. A theory is formulated for electromechanical instabilities of thermoplastics under different mechanical constraints. We find that the instabilities generally occur in thermoplastics when temperature is above their glass transition temperatures and electric field reaches a critical value. The critical electric field for the instabilities scales with square root of yield stress of the thermoplastic and depends on its Young's modulus and hardening property.

Wang, Qiming; Niu, Xiaofan; Pei, Qibing; Dickey, Michael D.; Zhao, Xuanhe

2012-01-01

134

Electromagnetic radiation calorimetry of thermoplastics, elastomers, and composite systems  

SciTech Connect

Microwave radiation for processing of glassy and semicrystalline thermoplastics, elastomeric polymers and composites was investigated. The goal was to reveal the relationship between polymer structure and microwave absorptivity, and hence processability. Specimens were subjected to an electric field at 2.45 GHz either inside a rectangular waveguide or in a cylindrical resonant cavity. Applicator with less than 100 watts applied power. Both travelling wave modes and standing wave modes were examined. Temperatures, powers and times were recorded, leading to the concept of microwave calorimetry. Low frequency dynamic mechanical and dielectric frequency-temperature spectra were obtained on the materials and combined to conveniently extrapolate structure-property relationships into the GHz region. A correlation was found between the dielectric properties of various polymers and the dipole moments of small molecule analogues. Evaluating heatability was most accurately determined by the magnitude of ({epsilon}{sub s} - {epsilon}{sub {infinity}}), the oscillator strength. The value of ({epsilon}{sub s} - {epsilon}{sub {infinity}}) should be used together with the distribution of relaxation times and the activation energies of dipolar dispersion to predict heatability for microwave processing. The critical temperatures, T{sub c}, of dielectric loss were obtained from the intercepts of positive slope tangents of heating rate versus temperature plots at 2.45 GHz for polymers. Microwave processing was rapid above the critical temperature where the maximum dielectric loss fell in the 2.45 GHz frequency domain for efficient coupling of energy to the polymers. Shifting the dielectric relaxation spectrum into the microwave region by directly or indirectly increasing the temperature was unique and of key importance to processability. A schematic model explains the behavior of two-phase materials subjected to microwave heating.

Chen, M.

1989-01-01

135

Deformational characteristics of thermoplastic elastomers  

NASA Astrophysics Data System (ADS)

This thesis focuses primarily on the structure-property relationships of poly (styrene-ethylene-butylene-styrene) triblock copolymer TPEs. First evidence for strain-induced crystallization occurring in certain SEBS block copolymers has been established using unique techniques like deformation calorimetry, combined in-situ small angle X-ray and wide angle X-ray diffraction (SAXD/WAXD). Also the ramifications of such strain-induced crystallization on the mechanical properties like cyclic hysteresis, stress relaxation/creep retention of these SEBS systems have been studied. In addition, the structural changes in the morphology of these systems on deformation have been investigated using combined SAXD/WAXD setup. Small angle X-ray diffraction probed the changes at the nano-scale of polystyrene (PS) cylinders, while wide angle X-ray diffraction probed the changes at molecular length scales of the amorphous/crystalline domains of the elastomeric mid-block in these systems. New structural features at both these length scales have been observed and incorporated into the overall deformation mechanisms of the material. Continuous processing techniques like extrusion have been used to obtain ultra long-range order and orientation in these SEBS systems. Thus well ordered crystal like hexagonal packing of cylinders, where in each element in this hexagonal lattice can be individually addressed without any grain boundaries can be realized using these robust techniques. The effect of long-range order/orientation on the mechanical properties has been studied. In addition, these well ordered systems serve as model systems for evaluating deformation mechanisms of these SEBS systems, where the relative contributions of each of the phases can be estimated. EPDM/i-PP thermoplastic vulcanizates (TPVs) have micron size scale phase separated morphologies of EPDM rubber dispersed in a semicrystalline i-PP matrix as a result of the dynamic vulcanization process. Confocal microscopy studies, along with scanning electron microscopy (SEM) studies show that the morphology of these EPDM/i-PP systems resembles a microcellular "filled" foam in which i-PP occupies the strut regions and EPDM the inner core. Based on this, an analytical model has been developed that takes into account composition information, molecular weight, cure state and morphology into account.

Indukuri, Kishore K.

136

Polypropylene ionic thermoplastic elastomers: Synthesis and properties  

Microsoft Academic Search

Polypropylene ionic thermoplastic elastomers have been prepared by melt radical grafting of maleic anhydride onto polypropylene in the presence of N-bromosuccinimide followed by neutralization of the resulting elastomeric grafted polypropylene using sodium salts. Sodium hydroxide and sodium acetate were compared in aqueous solution, as anhydrous or hydrated powders. The neutralization reaction was followed by Fourier transform infrared spectroscopy, allowing the

Dimitri D. J. Rousseaux; Xavier Drooghaag; Michel Sclavons; Pierre Godard; Veronique Carlier; Jacqueline Marchand-Brynaert

2010-01-01

137

Carbon Fiber\\/Thermoplastic Overwrapped Gun Tube  

Microsoft Academic Search

The emphasis on lightweight large caliber weapons systems has placed the focus on the use of advanced composite materials. Using traditional thermoset composites has been difficult, as the coefficient of thermal expansion mismatch between the steel substrate and the composite jacket causes a gap after manufacturing. Using a thermoplastic resin and a cure on the fly process has improved the

Andrew Littlefield; Edward Hyland; Andrew Andalora; Nathaniel Klein; Robert Langone; Robert Becker

2006-01-01

138

Material fire properties and predictions for thermoplastics  

Microsoft Academic Search

Ignition and burning rate data are developed for nylon 6\\/6, polyethylene, polypropylene and black polycast PMMA in a cone calorimeter heating assembly. The objective is to examine a testing protocol that leads to the prediction of ignition and burning rate for thermoplastics from cone calorimeter data. The procedure consists of determining material properties, i.e. thermal inertia, specific heat, thermal conductivity,

D. Hopkins; J. G. Quintiere

1996-01-01

139

Thermoplastic Composite Materials for Aerospace Applications  

NASA Astrophysics Data System (ADS)

Mechanical and thermo-physical properties of composites materials with thermoplastic matrix (PEEK/IM7, TPI/IM7 and PPS/IM7) used for aerospace applications have been analyzed as function of two different process techniques: compression molding and fiber placement process ``hot gas assisted.''

Casula, G.; Lenzi, F.; Vitiello, C.

2008-08-01

140

Biodegradable Thermoplastic Polyurethanes Incorporating Polyhedral Oligosilsesquioxane  

Microsoft Academic Search

A new hybrid thermoplastic polyurethane (TPU) system that incorporates an organic, biodegradable poly(D,L- lactide) soft block with a hard block bearing the inorganic polyhedral oligosilsesquioxane (POSS) moiety is introduced and studied. Changes in the polyol composition made through variation of the hydrophilic initiator molecular weight show direct control of the final transition temperatures. Incorporating POSS into the hard segments allows

Pamela T. Knight; Kyung Min Lee; Haihu Qin; Patrick T. Mather

2008-01-01

141

The fractography of thermoplastic textile fibres  

Microsoft Academic Search

The use of a scanning electron microscope in studying the fractography of fibres is described and its advantages explained. A common pattern of break is shown for thermoplastic fibres at extension rates up to 8×10-2 sec-1. This involves a slow crack which becomes catastrophic at the critical crack length. The critical crack length depends upon the rate of extension, and

J. W. S. Hearle; P. M. Cross

1970-01-01

142

Prehydrolyzed Cellulose as Reinforcing Filler for Thermoplastics  

Microsoft Academic Search

This paper presents the results of an experimental study of the mechanical properties of composites consisting of prehydrolyzed cellulose and thermoplastic matrices. The main feature of prehydrolyzed cellulose fibres is a high degree of brittleness, permitting the fibres to be finely comminuted in the shear field of normal compounding and processing machinery. Such an effect can be anticipated to improve

A. Boldizar; C. Klason; J. Kubát; P. Näslund; P. Sáha

1987-01-01

143

New non-covalent strategies for stable surface treatment of thermoplastic chips.  

PubMed

In order to be more extensively used outside of research laboratories, lab-on-chip technologies must be mass-produced using low-cost materials such as thermoplastics. Thermoplastics, however, are generally hydrophobic in their native state, which makes them unsuitable for direct use with biological samples in aqueous solution, and thus require surface coating. This coating should be robust, inexpensive and simple to implement, in order not to hinder the industrial advantage of thermoplastic chips. Cyclic Olefin Copolymer (COC) is a particularly appealing polymer, but it is also difficult to functionalize due to its chemical inertness. Here we introduce and compare the performance of two new approaches for COC coating. One relies on the use of a commercial triblock copolymer, Pluronic® F127. The second approach uses new copolymers synthesized by radical polymerization, and consisting of a dimethylacrylamide (DMA) backbone carrying aliphatic side chains (C22). Two DMA-C22 copolymers were synthesized with various C22/DMA ratios: DMA-S at 0.175% and DMA-M at 0.35%. Different physicochemical properties of the polymers such as critical micellar concentration (CMC), water contact angle, electroosmosis were investigated. Coated COC chips were then tested for their ability to reduce the adsorption of proteins, microparticles, and for protein electrophoresis. For each application we found an optimal treatment protocol to considerably improve the performance of the thermoplastic chip. These treatments use physisorption in situ which requires no photografting or chemical reaction and can be performed by a simple incubation either after chip production, or just prior to use. PMID:24061577

Perez-Toralla, Karla; Champ, Jérôme; Mohamadi, Mohamad Reza; Braun, Olivier; Malaquin, Laurent; Viovy, Jean-Louis; Descroix, Stéphanie

2013-10-15

144

Metallic glass mold insert for hot embossing of polymers  

NASA Astrophysics Data System (ADS)

Molding of micro components from thermoplastic polymers (TPs) has become a routinely used industrial production process. To find hard, ductile and durable material for mold insert and to fabricate the mold insert are two big challenges for the thermoplastic polymers fabrication techniques. We report that a Pd-based metallic glass (MG) mold insert was readily fabricated in its supercooled liquid region, and the atomic force microscope measurement and time-temperature-transformation analysis show that the metallic glass mold insert has very fine surface quality and long service life. We show that the metallic glasses, which have remarkable mechanical properties and excellent thermoplastic forming ability, are new ideal materials for hot embossing mold insert of thermoplastic polymers.

Ma, J.; Zhang, X.; Wang, W. H.

2012-07-01

145

Crystallinity of On-Line Consolidated Thermoplastic Composites  

Microsoft Academic Search

Processing of high-quality thermoplastic composite parts by laser-assisted tape consolidation involves in-situ melting and solidification of the thermoplastics matrix material. In contrast to autoclave processing, fusion of the matrix material occurs locally, preventing both the development of residual stresses and fiber buckling in the inner layer. High temperature thermoplastics such as Polyetheretherketone (PEEK) or Polyetherketoneketone (PEKK), are semicrystalline. The level

Christoph M. Pistor; Selçuk I. Güçeri

1999-01-01

146

Thermoplastics-moving into series production  

NASA Astrophysics Data System (ADS)

Continuous fiber reinforced thermoplastic products are gradually moving from the development phase into series production. The relative simplicity and cost-effectiveness of a number of innovative manufacturing technologies provides the incentive for their application. Examples of technologies developed and in production are thermofolding, deep-drawing, press forming, transition molding and welding. These manufacturing methods are dependable and reproducible. The development of a product must be closely tuned to its final application. Therefore, close cooperation between the part manufacturer, the material supplier and the end-user is essential. Thermoplastics are presently applied in a number of civil aircraft programs in both structural and non-structural components. Examples are aircraft flap ribs, ice protection plates and wing panels.

Offringa, Arnt R.

147

On the fracture of reinforced thermoplastics  

Microsoft Academic Search

In the designing of engineering fiber-reinforced thermoplastics and of the processing technology to make such, their behaviour at failure should be taken into consideration. The processes of deformation and failure from compression were investigated for polycarbonate and polyarylate reinforced with polyaramide fiber, particularly, poly-m-phenyleneisophthalamide and poly-p-amidobenzimidazole, the results obtained being described in this paper.The acoustic emission (AE) technique was used

V. V. Meshkov; O. V. Kholodilov; A. I. Sviridenok

1995-01-01

148

Biodegradation of Thermoplastic Polyurethanes from Vegetable Oils  

Microsoft Academic Search

Thermoplastic urethanes based on polyricinoleic acid soft segments and MDI\\/BD hard segments with varied soft segment concentration\\u000a were prepared. Soft segment concentration was varied from, 40 to 70 wt%. Biodegradation was studied by respirometry. Segmented\\u000a polyurethanes with soft segments based on polyricinoleic acid degrade relatively slow losing about 11% carbon after 30 days,\\u000a but faster than corresponding petrochemical polyesterurethanes. Since biodegradation proceeds

Zoran S. Petrovic ´; Yijin Xu; Jelena Mili?; Gregory Glenn; Artur Klamczynski

2010-01-01

149

THERMAL BEHAVIOR DURING THERMOPLASTIC COMPOSITES RESISTANCE WELDING  

Microsoft Academic Search

Two- and three- dimensional heat transfer finite element models of the resistance-welding process for joining thermoplastic composite laminates were developed. The models simulated a resistance welded single lap-shear joint using 16-layer unidirectional APC- 2\\/AS4 laminates. The heating element consisted of a stainless steel metal mesh sandwiched between neat PEEK films. The heat was generated at the bond surface by applying

Edith Talbot; Ali Yousefpour; Pascal Hubert; Mehdi Hojjati

150

Temperature dependence of high strain-rate impact fracture behaviour in highly filled polymeric composite and plasticized thermoplastic propellants  

Microsoft Academic Search

The effect of temperature and strain-rate on the fracture behaviour during high strain-rate (~ 103 sec-1) impact of two highly filled polymeric composite propellants (containing segmented polyurethanes based on hydroxy-term inated polybutadiene (HTPB) or glycidyl azide polymer (GAP) filled with ammonium perchlorate (AP) particles) and a plasticized thermoplastic (cast double base (CDB) nitrocellulose-nitroglycerine) propellant have been examined over a wide

S. Y. Ho; C. W. Fong

1987-01-01

151

Plasticization of an ionic thermoplastic elastomer based on a zinc sulfonated ethylene—propylene—diene terpolymer of high ethylene content  

Microsoft Academic Search

Zinc sulfonated ethylene—propylene—diene terpolymer (EPDM) behaves as an ionic thermoplastic elastomer. Both paraffin oil and dimethyl sulfoxide (DMSO) act as plasticizers for this polymer; while paraffin oil plasticizes the hydrocarbon backbone, DMSO plasticizes the ionic domains. Results obtained from dynamic mechanical analysis (d.m.a.) show that DMSO does not affect the glass—rubber transition temperature (Tg), occurring at around ?26°C, but adversely

D. G. Peiffer

1996-01-01

152

Effect of Nickel–Cobalt–Zinc Ferrite Filler on Magnetic and Thermal Properties of Thermoplastic Natural Rubber Composites  

Microsoft Academic Search

A sample of Ni0.25Co0.25Zn0.5Fe2O4 ferrite was prepared by a double-staged sintering method in air. Thermoplastic natural rubber (TPNR) was prepared by melt blending of natural rubber (NR), liquid natural rubber (LNR), and high density polyethylene (HDPE) in an internal mixer Brabender Plasticorder PL 2000. Magnetic polymer composites were prepared from the ferrite and TPNR matrix using the same melt blending

Dwi Puryanti; Sahrim Hj. Ahmad; Mustaffa Hj. Abdullah; Ahmad Nazlim Hj. Yusoff

2007-01-01

153

An overview of the polymer-to-metal direct-adhesion hybrid technologies for load-bearing automotive components  

Microsoft Academic Search

The work published in the open literature dealing with various polymer metal hybrid (PMH) approaches used to promote direct (adhesive-free) adhesion between metal and injection-molded thermoplastics is reviewed and critiqued. Different approaches are categorized as follows: (a) micro-scale polymer-to-metal mechanical interlocking; (b) in-coil or stamped-part pre-coating for enhanced adhesion; and (c) chemical modifications of the injection-molded thermoplastics for enhanced polymer-to-metal

M. Grujicic; V. Sellappan; M. A. Omar; Norbert Seyr; Andreas Obieglo; Marc Erdmann; Jochen Holzleitner

2008-01-01

154

Thermoforming of Continuous Fibre Reinforced Thermoplastic Composites  

NASA Astrophysics Data System (ADS)

The introduction of new materials, particularly for aerospace products, is not a simple, quick or cheap task. New materials require extensive and expensive qualification and must meet challenging strength, stiffness, durability, manufacturing, inspection and maintenance requirements. Growth in industry acceptance for fibre reinforced thermoplastic composite systems requires the determination of whole life attributes including both part processing and processed part performance data. For thermoplastic composite materials the interactions between the processing parameters, in-service structural performance and end of life recyclability are potentially interrelated. Given the large number and range of parameters and the complexity of the potential relationships, understanding for whole life design must be developed in a systematic building block approach. To assess and demonstrate such an approach this article documents initial coupon level thermoforming trials for a commercially available fibre reinforced thermoplastic laminate, identifying the key interactions between processing and whole life performance characteristics. To examine the role of the thermoforming process parameters on the whole life performance characteristics of the formed part requires a series of manufacturing trials combined with a series of characterisation tests on the manufacturing trial output. Using a full factorial test programme and considering all possible process parameters over a range of potential magnitudes would result in a very large number of manufacturing trials and accompanying characterisation tests. Such an approach would clearly be expensive and require significant time to complete, therefore failing to address the key requirement for a future design methodology capable of rapidly generating design knowledge for new materials and processes. In this work the role of mould tool temperature and blank forming temperature on the thermoforming of a commercially available thermoplastic based composite laminate is investigated followed by post processed part characterization. Key findings include an optimized composite processing window, and the influence of raw material blank forming temperature and mould tool temperature on part crystallinity and flexural strength. This process study forms one element of a major project structure which has been designed to address the gap between design, analysis and manufacturing, using at its core, a digital framework for the creation and management of performance parameters related to the lifecycle performance of thermoplastic composite structures.

McCool, Raurí; Murphy, Adrian; Wilson, Ryan; Jiang, Zhenyu; Price, Mark

2011-05-01

155

Thermoforming of Continuous Fibre Reinforced Thermoplastic Composites  

SciTech Connect

The introduction of new materials, particularly for aerospace products, is not a simple, quick or cheap task. New materials require extensive and expensive qualification and must meet challenging strength, stiffness, durability, manufacturing, inspection and maintenance requirements. Growth in industry acceptance for fibre reinforced thermoplastic composite systems requires the determination of whole life attributes including both part processing and processed part performance data. For thermoplastic composite materials the interactions between the processing parameters, in-service structural performance and end of life recyclability are potentially interrelated. Given the large number and range of parameters and the complexity of the potential relationships, understanding for whole life design must be developed in a systematic building block approach. To assess and demonstrate such an approach this article documents initial coupon level thermoforming trials for a commercially available fibre reinforced thermoplastic laminate, identifying the key interactions between processing and whole life performance characteristics. To examine the role of the thermoforming process parameters on the whole life performance characteristics of the formed part requires a series of manufacturing trials combined with a series of characterisation tests on the manufacturing trial output. Using a full factorial test programme and considering all possible process parameters over a range of potential magnitudes would result in a very large number of manufacturing trials and accompanying characterisation tests. Such an approach would clearly be expensive and require significant time to complete, therefore failing to address the key requirement for a future design methodology capable of rapidly generating design knowledge for new materials and processes. In this work the role of mould tool temperature and blank forming temperature on the thermoforming of a commercially available thermoplastic based composite laminate is investigated followed by post processed part characterization. Key findings include an optimized composite processing window, and the influence of raw material blank forming temperature and mould tool temperature on part crystallinity and flexural strength. This process study forms one element of a major project structure which has been designed to address the gap between design, analysis and manufacturing, using at its core, a digital framework for the creation and management of performance parameters related to the lifecycle performance of thermoplastic composite structures.

McCool, Rauri; Murphy, Adrian; Wilson, Ryan; Jiang Zhenyu; Price, Mark [School of Mechanical and Aerospace Engineering, Queen's University Belfast, Northern Ireland (United Kingdom)

2011-05-04

156

Aminosilane layers on the plasma activated thermoplastics: Influence of solvent on its structure and morphology.  

PubMed

The chemistry and the structure of aminosilane layer on the plasma activated thermoplastic substrates, e.g., polycarbonate (PC), polystyrene (PS), poly(methyl methacrylate) (PMMA), and cyclic olefin co-polymer (COC) were investigated at the molecular level. The nature of the surface functional groups of the silane layers prepared by solution phase deposition in aqueous and anhydrous solvents were studied using various techniques including ellipsometry, goniometry, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance infrared spectroscopy (ATR-IR). The XPS analyses revealed the presence of various oxygen functionalities on the plasma activated thermoplastics. Considerable differences were observed for the structure of aminosilane depending on the solvent used for the reaction. Deposition from aqueous solution resulted in relatively flat and smooth surfaces with consistent thickness compared to the anhydrous solution deposition. In the former case, 33% of the total nitrogen accounted for protonated amine and 16% for the free amino groups. In the latter, only 6% accounted for the protonated amine. The point of zero charge (pzc), on the aminosilane modified PC was found to be around 7, indicated that the surface is positively charged below pH 7 and negatively charged above pH 7. The surface analysis data suggested that various interactions are possible between the plasma activated thermoplastic surface and the aminosilane. In general, they are bound to the surface through covalent bond formation between the oxygen functionalities on the thermoplastic surface and the amino or the silanol groups of the aminosilane. PMID:24050640

Sunkara, Vijaya; Cho, Yoon-Kyoung

2013-08-31

157

Thermoplastic encapsulation of waste surrogates by high-shear mixing  

SciTech Connect

Brookhaven National Laboratory (BNL) has developed a robust, extrusion-based polyethylene encapsulation process applicable to a wide range of solid and aqueous low-level radioactive, hazardous and mixed wastes. However, due to the broad range of physical and chemical properties of waste materials, pretreatment of these wastes is often required to make them amenable to processing with polyethylene. As part of the scope of work identified in FY95 {open_quotes}Removal and Encapsulation of Heavy Metals from Ground Water,{close_quotes} EPA SERDP No. 387, that specifies a review of potential thermoplastic processing techniques, and in order to investigate possible pretreatment alternatives, BNL conducted a vendor test of the Draiswerke Gelimat (thermokinetic) mixer on April 25, 1995 at their test facility in Mahwah, NJ. The Gelimat is a batch operated, high-shear, high-intensity fluxing mixer that is often used for mixing various materials and specifically in the plastics industry for compounding additives such as stabilizers and/or colorants with polymers.

Lageraaen, P.R.; Kalb, P.D.; Patel, B.R.

1995-12-01

158

The High Frequency Welding Aptitude of Thermoplastic Polymers  

Microsoft Academic Search

The usage of plastic materials in industry suffered an important increase in the last 50 years, and development of new welding technologies of these materials was the main focus. This development is an effect of these new components asked in design phase in the innovative fields as medical, automotive and packaging industry (2, 5). In this direction, the welding of

ION MITELEA; NICOLAIE VARZARU; ILARE BORDEASU; MIHAELA POPESCU

2009-01-01

159

Numerical model of CO 2 laser welding of thermoplastic polymers  

Microsoft Academic Search

Nowadays laser welding of plastics can offer flexible seam contouring, minimal heat input, mechanical stress and consistent weld quality. Therefore the laser welding represents an alternative to conventional joining techniques for plastics.The availability of reliable numerical models can help researchers and engineers to give a better place in industrial scale situations to plastics laser welding.In this paper thermo-morphologic and mechanical

Giuseppe Casalino; Elhem Ghorbel

2008-01-01

160

Thermoplastic splint for use after nasal fracture.  

PubMed

I have used this splint on 16 patients between November 1992 and July 1993. The device works as well as or better than other similarly designed thermoplastic nasal splints that are commercially available, and it is significantly less expensive. Commercially available splints run about 5 to 10 dollars per unit. This device as described costs approximately 50 cents per unit. This method of external splinting of the nose is extremely reliable and satisfactory to both myself and the patient. No splint is unobtrusive, and I have found that my patients like these bright and colorful splints. PMID:8028925

Drezner, D A

1994-07-01

161

Development of thermoplastic coated multifunctional transmission elements  

NASA Astrophysics Data System (ADS)

We report on key challenges of the development of steel cords reinforced thermoplastic elastomer composites with smart functionalities: adhesion tailoring for a durable mechanical load transfer through steel cords or other transmission elements by the use of surface treatments and primers, and integrated distributed temperature and strain sensing by the use of embedded fiber optic sensors. Traditional surface treatments including silane coupling agent were outperformed in processing time, adhesion and durability by a fast-curing coupling method using a UV-curable primer; and the integrated distributed temperature and strain sensing capability was demonstrated. The practical applications of the resulting multifunctional transmission element are then discussed in light of these results.

Golaz, B.; Michaud, V.; de Oliveira, R.; Månson, J.-A. E.

2012-03-01

162

Rheology and morphology of starch\\/synthetic polymer blends  

Microsoft Academic Search

Corn starch and maleic anhydride functionalized synthetic polymers were melt blended in a Haake twin-screw extruder. The amount of starch in the blends was 60 and 70% by weight. The synthetic polymer used was either styrene maleic anhydride (SMA) or ethylene propylene maleic anhydride copolymer (EPMA). The blends did not exhibit normal thermoplastic behavior; and hence, rheological data was obtained

K. Seethamrajul; M. Bhattacharya; U. R. Vaidya; R. G. Fulcher

1994-01-01

163

Newly improved polymer alloy systems for printed wiring boards  

Microsoft Academic Search

A novel laminating resin system using polymer alloy technologies was investigated to see if it could meet demands of high density printed wiring boards. An experimental study was carried out on thermoplastic and thermosetting polymer alloy systems. Two combinations of linear phenoxy resin and thermosetting epoxy resin were characterized to investigate the synergetic qualities of the resin systems. For one

S. Oka; T. Takahama; H. Nakajima

1989-01-01

164

Surface grafting of carboxylic groups onto thermoplastic polyurethanes to reduce cell adhesion  

NASA Astrophysics Data System (ADS)

The interaction of polymers with other materials is an important issue, being their surface properties clearly crucial. For some important polymer applications, their surfaces have to be modified. Surface modification aims to tailor the surface characteristics of a material for a specific application without affecting its bulk properties. Materials can be surface modified by using biological, chemical or physical methods. The aim of this work was to improve the reactivity of the thermoplastic polyurethane (TPU) material (Elastollan®) surface and to make its surface cell repellent by grafting carboxylic groups onto its surface. Two TPU materials were studied: a polyether-based TPU and a polyester-based TPU. The grafting efficiency was evaluated by contact angle measurements and by analytical determination of the COOH groups. Scanning electron microscopy (SEM) of the membranes surface was performed as well as cell adhesion tests. It was proved that the surfaces of the TPUs membranes were successfully modified and that cell adhesion was remarkably reduced.

Alves, P.; Ferreira, P.; Kaiser, Jean-Pierre; Salk, Natalie; Bruinink, Arie; de Sousa, Hermínio C.; Gil, M. H.

2013-10-01

165

Properties of Starch Blends with Biodegradable Polymers  

Microsoft Academic Search

Starch, one of the most inexpensive and most readily available of all natural polymers, can be processed into thermoplastic materials only in the presence of plasticizers and under the action of heat and shear. Poor water resistance and low strength are limiting factors for the use of materials manufactured only from starch, and hence the modification of starch is often

Xiu-Li Wang; Ke-Ke Yang; Yu-Zhong Wang

2003-01-01

166

Thermal stabilities of drops of burning thermoplastics under the UL 94 vertical test conditions.  

PubMed

The properties of polymer melts will strongly affect the fire hazard of the pool induced by polymer melt flow. In this study the thermal stabilities of eight thermoplastic polymers as well as their melting drops generated under the UL 94 vertical burning test conditions were investigated by thermogravimetric experiments. It was found that the kinetic compensation effect existed for the decomposition reactions of the polymers and their drops. For polymethylmethacrylate (PMMA), high impact polystyrene (HIPS), poly(acrylonitrile-butadiene-styrene) (ABS), polyamide 6 (PA6), polypropylene (PP) and low density polyethylene (LDPE), the onset decomposition temperature and the two decomposition kinetic parameters (the pre-exponential factor and the activation energy) of the drop were less than those of the polymer. However, the onset decomposition temperature and the two kinetic parameters of PC's drop were greater than those of polycarbonate (PC). Interestingly, for polyethylenevinylacetate (EVA18) the drop hardly contained the vinyl acetate chain segments. Similarly, for the PMMA/LDPE blends and the PMMA/PP blends, when the volume fraction of PMMA was less than 50% the drop hardly contained PMMA, implying that the blend would not drip until PMMA burned away and its surface temperature approached the decomposition temperature of the continuous phase composed of LDPE or PP. PMID:23298738

Wang, Yong; Zhang, Jun

2012-12-20

167

Applications of PHB - a microbially produced biodegradable thermoplastic  

Microsoft Academic Search

ICI has recently made available a new range of environmentally degradable thermoplastics made by bacteria from renewable substrates. Potentially the next generation of commodity plastics, these are now being evaluated in speciality applications.

P A Holmes

1985-01-01

168

Thermoplastic Single-Ply Roof Relieves Water Damage and Inconvenience.  

ERIC Educational Resources Information Center

|Assesses use of thermoplastic single-ply roofs by North Carolina's Mars Hill College to prevent leaks, reduce maintenance costs, and enhance the value of their older historic buildings. Administrators comment on the roof's installation efficiency and cleanliness. (GR)|

Williams, Jennifer Lynn

2002-01-01

169

Influence of oxidized starch on the properties of thermoplastic starch.  

PubMed

Thermoplastic starch was prepared by adding oxidized starches and glycerol together into starch. The addition of oxidized starch improved the rheological properties and also increased the toughness of thermoplastic starch. Compared with TPS30, the elongation at break increased from 126.8% to 152.5% when 5wt% OS 117% was added. Good compatibility of thermoplastic starch between the matrix and oxidized starch was confirmed by SEM. The addition of oxidized starch lowered the storage modulus and glass transition temperature (Tg) of thermoplastic starch, decreasing Tg from 34.1 to 30°C when 10 wt% OS117% was added. The thermal stability of blending was improved by adding oxidized starches, i.e. when 5 wt% OS70% was added, T5% increased from 134 to 156°C. PMID:23688492

Zhang, Yu-Rong; Wang, Xiu-Li; Zhao, Guo-Ming; Wang, Yu-Zhong

2013-04-12

170

Low-Cost Forming Influence on Reinforced Thermoplastic Mechanical Properties.  

National Technical Information Service (NTIS)

This report describes a study of the influence of low-cost forming methods on the mechanical properties of reinforced thermoplastics. Two tasks comprise the main body of the study; one establishes a relationship between processing parameters (time/pressur...

D. J. Hoffstedt L. C. Ritter D. J. Toto

1981-01-01

171

Characterization of Glass-Filled Engineering Thermoplastic Composites.  

National Technical Information Service (NTIS)

Characterization of three engineering thermoplastic (TP) materials has been carried out to assess suitability for Mound applications: Poly(etheretherketone) (PEEK), Poly(etherimide) (PEI), and Poly(ethersulfone) (PES). Analyses included: thermogravimetric...

A. B. Nease R. B. Whitaker R. O. Yelton

1983-01-01

172

Atomically smooth surfaces through thermoplastic forming of metallic glass  

NASA Astrophysics Data System (ADS)

We demonstrate that atomically smooth surfaces can be generated by thermoplastic forming of metallic glasses. This is enabled by the flow associated with the contact-line motion which removes rough surface layer from the advancing metallic glass-air interface. The thermoplastically formed surface is two orders of magnitude smoother than a polished surface of the same alloy. This process is capable of generating atomically smooth surfaces and replicating nanoscale features in a single processing step, providing a versatile toolbox for nanofabrication.

Kumar, Golden; Staffier, Peter A.; Blawzdziewicz, Jerzy; Schwarz, Udo D.; Schroers, Jan

2010-09-01

173

Some properties of thermoplastic mixtures for forming ceramics by extrusion  

SciTech Connect

The change in the rheological properties of mixtures for plastic forming based on cordierite and aluminum nitride as a function of the composition of the thermoplastic binder and the temperature is considered. A supposition on the influence of the ratio between the crystalline and the amorphous components of the thermoplastic dispersion medium on the properties of the mixture is made. Some recommendations on forming of ceramic pieces are given.

Mosin, Yu.M.; Leonov, V.G. [D.I. Mendeleev Russian Chemical and Technological Univ., Moscow (Russian Federation)

1995-11-01

174

Thermoplastic Explosive Compositions on the Base of Hexanitrohexaazaisowurtzitane  

Microsoft Academic Search

Hexanitrohexaazaisowurtzitane is an azostructural compound known as CL-20. We performed a series of experiments with CL-20 synthesized in Russia to evaluate the possibility to use it in pressed high explosive compositions. We used it in thermoplastic compositions both with an inert binder and energetic binder. The compositions were conventionally named CL-20И and CL-20A. It was determined that the thermoplastic compositions

V. P. Ilyin; S. P. Smirnov; E. V. Kolganov; Yu. G. Pechenev

2006-01-01

175

Thermoplastic Explosive Compositions on the Base of Hexanitrohexaazaisowurtzitane  

Microsoft Academic Search

Hexanitrohexaazaisowurtzitane is an azostructural compound known as CL-20. We performed a series of experiments with CL-20 synthesized in Russia to evaluate the possibility to use it in pressed high explosive compositions. We used it in thermoplastic compositions both with an inert binder and energetic binder. The compositions were conventionally named CL-20 Icy and CL-20A. It was determined that the thermoplastic

V. P. Ilyin; S. P. Smirnov; E. V. Kolganov; Yu. G. Pechenev

2006-01-01

176

Fabrication of optical waveguides in thermosetting polymers using hot embossing  

Microsoft Academic Search

Hot embossing is an effective technique that structures high-precision micro-patterns of thin polymer films, such as most thermoplastic polymers, using a hard master for optical applications. This work presents a new hot embossing process for the fabrication of polymeric optical waveguides in thermosetting polymers. The near field pattern of the single-mode channel waveguides was observed, and the propagation loss of

Choon-Gi Choi

2004-01-01

177

A new technology for sandwich plates and structures based on the use of in-situ foamable thermoplastic films  

NASA Astrophysics Data System (ADS)

The cost effectiveness of structures in transports is basically depending on the operational capability and availability, the so called structure effectiveness, per unit cost. These costs are mainly determined by the cost to manufacture (acquisition costs) and the costs to operate (mass) and to maintain (damage sensitivity). In this paper the attention is focused on a new approach leading to efficiency improving sandwich material concepts, structures and related manufacturing processes, satisfying the value for money criterion as formulated by the cost effectiveness criterion. The sandwich materials and technology applied are based on the use of thermoformable continuous fiber reinforced thermoplastic polymers, in particular E-glass reinforced polyetherimide (PEI).

Beukers, Adriaan

178

A Solvent Resistant, Thermoplastic Aromatic Poly(Imidesulfone) and Process for Preparing Same.  

National Technical Information Service (NTIS)

A process for preparing a thermoplastic poly(imidesulfone) is disclosed. This resulting material has thermoplastic properties which are generally associated with polysulfones but not polyimides, and solvent resistance which is generally associated with po...

D. A. Yamaki T. L. St.Clair

1982-01-01

179

Woodpulp fibres as reinforcements for high-melting engineering thermoplastics for \\  

Microsoft Academic Search

Although natural fibre reinforced commodity thermoplastics have a wide range of interior automotive applications, there have been few reports of cellulosic fibre-reinforced engineering thermoplastics. The common belief is that the only thermoplastics amenable to natural-fibre reinforcement are limited to low-melting commodity thermoplastics (below 180°C) like polyethylene and polypropylene. We have succeeded in developing materials and methods for compounding purified cellulosic

Daniel F. Caulfield; Rodney E. Jacobson; Karl D. Sears; John H. Underwood

180

Transparent thermoplastics: Replication of diffractive optical elements using micro-injection molding  

NASA Astrophysics Data System (ADS)

Small plastic components with sub-micron and micron gratings for diffractive optics were prepared by micro-injection molding. The aim of the work was to improve the filling of binary diffractive gratings with high aspect ratio by varying the molding parameters. Tests were made under conventional processing conditions with four transparent thermoplastics: polycarbonate (PC), cyclo-olefin polymer (COP), styrene acrylonitrile copolymer (SAN), and hexafluoropropylene tetrafluoroethylene ethylene terpolymer (HFP TFE Et). Melt and mold temperatures were kept as recommended by the manufacturer. Other molding parameters (injection speed, shot size, vacuum, holding pressure, and injection plunger diameter) were varied, and their effect on the profile of the gratings was measured by atomic force microscopy. The filling of the gratings (500 nm and 1000 nm) was clearly affected by injection speed, shot size, and injection piston diameter, but the most significant factor was the type of material. Replication fidelity was highest with PC and lowest with SAN.

Kalima, V.; Pietarinen, J.; Siitonen, S.; Immonen, J.; Suvanto, M.; Kuittinen, M.; Mönkkönen, K.; Pakkanen, T. T.

2007-10-01

181

Electrical Properties of a Thermoplastic Polyurethane Filled with Titanium Dioxide Nanoparticles  

SciTech Connect

In this study we report a nanodielectric system composed of pre-synthesized nanoparticles embedded in an elastomer. Nanoparticles of titanium dioxide were synthesized in an aqueous solution of titanium chloride and polyethylene glycol. The nanoparticles were blended in a twin screw extruder with a thermoplastic, polyurethane (Morthane PS455-203), to form nanodielectrics at three different weight fractions of titanium dioxide. Impedance spectroscopy was employed to study polymer dynamics and the influence of nanoparticles on relaxation. The segmental relaxation associated with the glass transition of the polyurethane matrix, and the local relaxations associated with short range motions of polar groups were investigated at wide ranges of frequency (20 Hz-1 MHz) and temperature (300-20 K). The dielectric breakdown strength of the nanodielectrics was also measured to characterize their insulating properties and their potential for use in high voltage applications.

Polyzos, Georgios [ORNL; Tuncer, Enis [ORNL; Koerner, Hilmar [Air Force Research Laboratory, Wright-Patterson AFB, OH; Kidder, Michelle [ORNL; Vaia, Richard [Air Force Research Laboratory, Wright-Patterson AFB, OH; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL

2010-01-01

182

Highly conductive thermoplastic composites for rapid production of fuel cell bipolar plates  

DOEpatents

A low cost method of fabricating bipolar plates for use in fuel cells utilizes a wet lay process for combining graphite particles, thermoplastic fibers, and reinforcing fibers to produce a plurality of formable sheets. The formable sheets are then molded into a bipolar plates with features impressed therein via the molding process. The bipolar plates formed by the process have conductivity in excess of 150 S/cm and have sufficient mechanical strength to be used in fuel cells. The bipolar plates can be formed as a skin/core laminate where a second polymer material is used on the skin surface which provides for enhanced conductivity, chemical resistance, and resistance to gas permeation.

Huang, Jianhua [Blacksburg, VA; Baird, Donald G [Blacksburg, VA; McGrath, James E [Blacksburg, VA

2008-04-29

183

Shear Strength of Single Lap Joint Aluminium-Thermoplastic Natural Rubber (Al-TPNR) Laminated Composite  

NASA Astrophysics Data System (ADS)

In this work, we studied the effect of surface treatment on the aluminium surface and a coupling agent to improve adhesion between aluminium with organic polymer. Thermoplastic natural rubber (TPNR) matrix was prepared by melt blending of natural rubber (NR), liquid natural rubber (LNR) compatibilizer, linear low density polyethylene (LLDPE) and polyethylene grafted maleic anhydride (PE-g-MAH). The PEgMAH concentration used was varied from 0% - 25%. In addition, the aluminium surface was pre-treated with 3-glycidoxy propyl trimethoxy silane (3-GPS) to enhance the mechanical properties of laminated composite. It was found that the shear strength of single lap joint Al-TPNR laminated composite showing an increasing trend as a function of PE-g-MAH contents for the 3-GPS surface treated aluminium. Moreover, the scanning electron microscope (SEM) revealed that the strength improvement was associated with the chemical state of the compound involved.

Muzakkar, M. Z.; Ahmad, S.; Yarmo, M. A.; Jalar, A.; Bijarimi, M.

2013-04-01

184

Polymer alloys with balanced heat storage capacity and engineering attributes and applications thereof  

DOEpatents

A thermoplastic polymer of relatively low melt temperature is blended with at least one of thermosets, elastomers, and thermoplastics of relatively high melt temperature in order to produce a polymer blend which absorbs relatively high quantities of latent heat without melting or major loss of physical and mechanical characteristics as temperature is raised above the melting temperature of the low-melt-temperature thermoplastic. The polymer blend can be modified by the addition of at least one of fillers, fibers, fire retardants, compatibilisers, colorants, and processing aids. The polymer blend may be used in applications where advantage can be taken of the absorption of excess heat by a component which remains solid and retains major fractions of its physical and mechanical characteristics while absorbing relatively high quantities of latent heat.

Soroushian, Parviz (Lansing, MI)

2002-01-01

185

Silicone thermoplastic sheeting for treatment of facial scars: an improved technique.  

PubMed

Silicone thermoplastic sheeting has been used successfully in the management of hypertrophic and keloid scars resulting from thermal burn injuries. A technique is described that incorporates silicone thermoplastic sheeting for fabrication of a compression face mask. This technique combines the moldability of thermoplastic splinting materials with the therapeutic surface of silicone, yielding the advantages of both in a one-step process. PMID:10740514

Bradford, B A; Breault, L G; Schneid, T; Englemeier, R L

1999-06-01

186

Photoluminescent zinc oxide polymer nanocomposites fabricated using picosecond laser ablation in an organic solvent  

Microsoft Academic Search

Nanocomposites made of ZnO nanoparticles dispersed in thermoplastic polyurethane were synthesized using picosecond laser ablation of zinc in a polymer-doped solution of tetrahydrofuran. The pre-added polymer stabilizes the ZnO nanoparticles in situ during laser ablation by forming a polymer shell around the nanoparticles. This close-contact polymer shell has a layer thickness up to 30nm. Analysis of ZnO polyurethane nanocomposites using

Philipp Wagener; Shamsolzaman Faramarzi; Andreas Schwenke; Rupert Rosenfeld; Stephan Barcikowski

2011-01-01

187

Comprehensive Welding of Thermoplastics by a Diode Laser  

NASA Astrophysics Data System (ADS)

This paper deals with a development of “comprehensive" laser welding of thermoplastics with versatility in color and shape of products. Overlap welding of thermoplastics is one of the features of application of diode lasers. Most of thermoplastics are transparent to diode lasers; therefore it is need to weld plastic article with colorant. The influence of absorptance and transmittance of overlapping colored plastics were studied. Various colored plastics with infrared-transparent pigments were tested as the welding material. The appropriate absorptance and transmittance of overlapping colored plastic were examined. The feasibility of the technique of welding of transparent plastics using infrared-absorbing layer was also investigated. The temperature distribution within the plastics was calculated by numerical simulation in order to estimate the validity of the proposing experimental systems. It was confirmed by the experiments that the 35?m film, which shows only 10% in absorptance is enough to weld a pair of transparent articles as infrared-absorbing layer.

Sato, Kimitoshi; Saito, Takushi; Kurosaki, Yasuo

188

Silane coupling agents used for natural fiber\\/polymer composites: A review  

Microsoft Academic Search

Natural fiber reinforced polymer composites (NFPCs) provide the customers with more alternatives in the material market due to their unique advantages. Poor fiber–matrix interfacial adhesion may, however, negatively affect the physical and mechanical properties of the resulting composites due to the surface incompatibility between hydrophilic natural fibers and non-polar polymers (thermoplastics and thermosets). A variety of silanes (mostly trialkoxysilanes) have

Yanjun Xie; Callum A. S. Hill; Zefang Xiao; Holger Militz; Carsten Mai

2010-01-01

189

Multi-scale effects on deformation mechanisms of polymer nanocomposites: Experimental characterisation and numerical study  

Microsoft Academic Search

In order to make much stiffer, light weight and high performance material products, polymer nanocomposites play an emerging role in the material innovation. Unlike other thermoplastics, polymer nanocomposites are fabricated by introducing a small amount of solid nano-scale fillers (normally less than 5 wt%) such as nanoclay, carbon nanotubes or nanofibres into a plastic resin to dramatically enhance its stiffness,

Yu Dong

2008-01-01

190

Large-scale production, properties and commercial applications of polylactic acid polymers  

Microsoft Academic Search

Polylactic acids (PLA) are not new polymers. However, recent developments in the capability to manufacture the monomer economically from renewable feedstocks have placed these materials at the forefront of the emerging biodegradable plastics industry. Increasing realisation of the intrinsic properties of these polymers, coupled with a knowledge of how such properties can be manipulated to achieve compatibility with thermoplastics processing,

James Lunt

1998-01-01

191

Sulfur polymer cement as a low-level waste glass matrix encapsulant.  

National Technical Information Service (NTIS)

Sulfur polymer cement (SPC) is being considered as a matrix encapsulant for the Hanford low-level (activity) waste glass. SPC is an elemental sulfur polymer-stabilized thermoplastic that is fluid at 120 (degrees)C to 140(degrees)C. The candidate process w...

P. Sliva Y. B. Peng D. K. Peeler

1996-01-01

192

Natural and synthetic mineral silicates as functional nanoparticles in polymer composites  

Microsoft Academic Search

A new strategy is described for the substantial enhancement of the barrier properties for both a thermoset epoxy polymer and a thermoplastic polyolefin by sandwiching a novel self-supported clay fabric film between thin polymer sheets. The success of this strategy is attributed to the high orientation of clay nanolayers in the paper-like clay fabric films and to the filling of

Hua Shao

2009-01-01

193

Design of Zero-Birefringence Cross-Linked Polymers  

NASA Astrophysics Data System (ADS)

We analyzed thermoplastic methacrylate polymers and found that their birefringence during polymerization is due to both orientational and photoelastic birefringence. We designed zero-birefringence cross-linked polymers that do not exhibit birefringence during the polymerization process or elastic deformation, and deduced the contributions of cross-linking agents to photoelastic coefficient by analyzing binary cross-linked polymers. When photoelastic coefficient values of ternary cross-linked polymers were almost zero, their average in-plane birefringence was linearly related with the concentration of cross-linking agents. Finally, we designed and demonstrated two types of zero-birefringence cross-linked polymers.

Yamazaki, Sayuri; Tagaya, Akihiro; Koike, Yasuhiro

2010-02-01

194

Surface-Initiated ARGET ATRP and Characterization of Thermoplastic Elastomer Montomorillonite Composites  

NASA Astrophysics Data System (ADS)

Polymer nanocomposites, with enhanced properties as compared to their bulk polymer counterparts, are becoming more prominent in advanced material applications. Here we report the synthesis of poly(n-butyl acrylate-b-styrene) (PBA-b-PS) from the surface of functionalized montmorillonite clay via activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP). The ARGET mechanism allows for a substantial reduction in the amount of transition metal catalyst required. It also exhibits potential for eventual scale-up and the industrial adoption of ATRP as a versatile method for producing polymers with well-defined compositions and functionalities. The composite materials resemble traditional thermoplastic elastomer triblock copolymers, with the clay platelets dividing the central, rubbery PBA block. We used SAXS, NMR, and TEM to characterize the composition and structure of the composites. The resulting material properties were measured by tensile testing, dynamic mechanical analysis, and TGA. We anticipate the composites to have exceptional barrier properties due to the high degree of clay dispersion, which may lead to applications as recyclable packaging materials.

Easley, Jeffrey; Beck, Amanda; Ellison, Christopher

2010-03-01

195

Biodegradable, Elastic Shape-Memory Polymers for Potential Biomedical Applications  

Microsoft Academic Search

The introduction of biodegradable implant materials as well as minimally invasive surgical procedures in medicine has substantially improved health care within the past few decades. This report describes a group of degradable thermoplastic polymers that are able to change their shape after an increase in temperature. Their shape-memory capability enables bulky implants to be placed in the body through small

Andreas Lendlein; Robert Langer

2002-01-01

196

Effects of carbon nanoparticles on properties of thermoset polymer systems  

Microsoft Academic Search

Polymer nanocomposites are novel materials in which at least one of the dimensions of the reinforcing material is on the order of 100 nm or less. While thermoplastic nanocomposites have been studied very widely, there are fewer studies concerning the effect of nanoparticles on thermoset systems. Low temperature cure thermoset systems are very important for many important applications. In this

Siva Subramanyam Movva

2010-01-01

197

Optical properties of polymer\\/chalcogenide glass composite materials  

Microsoft Academic Search

The novel composite material based on middle density polyethylene on one hand and thermoplastic chalcogenide glass on other hand has been worked out. Both materials used in the research are highly transparent in the middle and far IR but refraction indexes of components differ dramatically. The basic materials, polymer and glass, have close viscosities at the temperature of polyethylene processing.

Edward Bormashenko; Roman Pogreb; Semion Sutovski

2000-01-01

198

Preparation and rheological behavior of polymer-modified asphalts  

Microsoft Academic Search

Different materials and methods were used to prepare and stabilize polymer-modified asphalts. Addition of thermoplastic elastomers improved some technically important properties of asphalt. Due to inherent factors like large density difference between asphalt and polyethylene, many physical methods in which the structure of asphalt is unchanged, failed to stabilize this system. The effect of addition of copolymers and a pyrolytic

Ali Akbar Yousefi

1999-01-01

199

Rheological properties of amorphous and semicrystalline polylactic acid polymers  

Microsoft Academic Search

Corn starch fermentation provides an abundant supply of lactic acid. Polymerization of lactic acid into polylactic acid (PLA) produces a biodegradable thermoplastic polyester with excellent functional properties comparable to many petroleum-based plastics. PLA polymers are made into useful items using thermal processes, such as injection molding and extrusion. Therefore, its rheological properties, especially the shear viscosity (?), have important effects

Qi Fang; Milford A Hanna

1999-01-01

200

A new class of bio-heat resisted polymer blend  

Microsoft Academic Search

Increasing in oil prices and environmental concerns is a driving force to seek out alternative materials. A completely biodegradable starch is a candidate for the alternative materials. Since the starch is brittle, it must be mixed with other polymers. In order to make a thermoplastic starch (TPS), we need a bio-compatiblizer to increase a degree of compatibilization. The biocompatibilzer can

Seongchan Pack; Takashi Kashiwagi; Tadanori Koga; Miriam Rafailovich

2009-01-01

201

Polymer\\/clay\\/wood nanocomposites: The effect of incorporation of nanoclay into the wood\\/polymer composites  

Microsoft Academic Search

Thermoplastic composites play an important role in our society. The uses of these composites range from cookware to components for the space shuttle. In recent years, researchers at Toyota developed numerous methods of preparation for composites made from olefins and inorganic fillers such as clay and calcium carbonate. Wood fibers have been used as reinforcing filler in polymer matrices for

Max E. Hetzer

2007-01-01

202

Processing and characterization of unidirectional thermoplastic nanocomposites  

NASA Astrophysics Data System (ADS)

The manufacture of continuous fibre-reinforced thermoplastic nanocomposites is discussed for the case of E-Glass reinforced polypropylene (PP) matrix and for E-Glass reinforced Polyamide-6 (Nylon-6), with and without dispersed nanoclay (montmorillonite) platelets. The E-Glass/PP nanocomposite was manufactured using pultrusion, whereas the E-Glass/Nylon-6 nanocomposite was manufactured using compression molding. Mechanical characterization of nanocomposites were performed and compared with traditional microcomposites. Compressive as well as shear strength of nanocomposites was improved by improving the yield strength of the surrounding matrix through the dispersion of nanoclay. Significant improvements were achieved in compressive strength and shear strength with relatively low nanoclay loadings. Initially, polypropylene with and without nanoclay were melt intercalated using a single-screw extruder and the pultruded nanocomposite was fabricated using extruded pre-impregnated (pre-preg) tapes. Compression tests were performed as mandated by ASTM guidelines. SEM and TEM characterization revealed presence of nanoclay in an intercalated and partially exfoliated morphology. Mechanical tests confirmed significant improvements in compressive strength (˜122% at 10% nanoclay loading) and shear strength (˜60% at 3% nanoclay loading) in modified pultruded E-Glass/PP nanocomposites in comparison with baseline properties. Uniaxial tensile tests showed a small increase in tensile strength (˜3.4%) with 3% nanoclay loading. Subsequently, E-Glass/Nylon-6 nanocomposite panels were manufactured by compression molding. Compression tests were performed according to IITRI guidelines, whereas short beam shear and uni-axial tensile tests were performed according to ASTM standards. Mechanical tests confirmed strength enhancement with nanoclay addition, with a significant improvement in compressive strength (50% at 4% nanoclay loading) and shear strength (˜36% at 4% nanoclay loading) when compared with the baseline E-Glass/Nylon-6. Uni-axial tensile tests resulted in a small increase in tensile strength (˜3.2%) with 4% nanoclay loading. Also, hygrothermal aging (50°C and 100% RH) of baseline and nanoclay modified (4%) E-Glass/Nylon-6 was studied. It was observed that the moisture diffusion process followed Fickian diffusion. E-Glass/Nylon-6 modified with 4% nanoclay loading showed improved barrier performance with a significant reduction (˜30%) in moisture uptake compared to baseline E-Glass/Nylon-6 composites. Significant improvement in mechanical properties was also observed in hygrothermally aged nanocomposite specimens when compared with the aged baseline composite.

Narasimhan, Kameshwaran

203

Method for preparing spherical thermoplastic particles of uniform size  

DOEpatents

Spherical particles of thermoplastic material of virtually uniform roundness and diameter are prepared by cutting monofilaments of a selected diameter into rod-like segments of a selected uniform length which are then heated in a viscous liquid to effect the formation of the spherical particles.

Day, J.R.

1975-11-17

204

Reinforcement of thermoplastic rejects in the production of manhole covers  

Microsoft Academic Search

Thermoplastic rejects are un-recyclable plastics that are either incinerated causing harmful emissions into the air or land-filled. A common problem associated with manhole covers is the theft of the cover made out of cast iron and then selling it on the black market leaving a large empty hole in the road causing many potential safety and health hazards. This paper

Salah El Haggar; Lama El Hatow

2009-01-01

205

Low temperature cure of unsaturated polyester resins with thermoplastic additives  

Microsoft Academic Search

A dilatometry and morphological study of the effect of the various thermoplastic additives on shrinkage control of unsaturated polyester (UP) resins cured at low temperatures is presented in this article. It was found that shrinkage control is closely related to the morphological changes during curing. There are two major transitions in the relationship of shrinkage and additive concentration that can

W Li; L. J Lee

2000-01-01

206

Crosslink densities and phase morphologies in thermoplastic vulcanizates  

Microsoft Academic Search

The degree of EPDM crosslinking during dynamic vulcanization of a PP\\/ EPDM thermoplastic vulcanizate (TPV) was modified by varying its phenolic curative content. The rise in TPV viscosity, the drop in its swelling, the change in its NMR MAS lineshape, and the increase in its EPDM domain AFM force modulation hardness verified the increase in EPDM crosslink density with increasing

Maria D Ellul; Andy H Tsou; Weiguo Hu

2004-01-01

207

Impact of aging conditions on mechanical properties of thermoplastic polyurethane  

Microsoft Academic Search

In this study, impact of environmental aging conditions on the mechanical properties of thermoplastic polyurethane (TPU) was investigated. Especially, effect of temperature on water diffusion has been studied. Water-sorption experiments, tensile test and dynamic mechanical thermal analysis (DMTA) were performed after immersion in distilled water at different temperatures (25, 70 and 90°C). The sorption process was analyzed by gravimetric measurements

A. Boubakri; N. Haddar; K. Elleuch; Y. Bienvenu

2010-01-01

208

The Adhesion Properties of an Ozone Modified Thermoplastic Olefin Elastomer  

Microsoft Academic Search

The adhesion properties of a thermoplastic olefin elastomer (TPO) after ozone exposure are studied with attenuated total reflection infrared spectroscopy (ATR), the lap shear test, and contact angle measurement. The ozone treatment is applied after the TPO is dip-coated with acrylic acid (AA) that is mixed with benzophenone, benzoyl peroxide (BPO), and azobisisobutyronitrile initiators. ATR spectra confirm the presence of

Feng Cheng; Shinn-Gwo Hong; Chi-An Ho

1998-01-01

209

Plastic-On-Plastic Tribological Properties of Thermoplastic Composites  

Microsoft Academic Search

A comprehensive study of the wear factor and coef ficient of friction for a series of fiber reinforced and internally lubricated thermoplastic composites including glass fiber and carbon fiber reinforcements and silicone fluid and PTFE lubri cants. Polycarbonate, nylon 6\\/6, PPS, acetal, and PBT resins were studied in the modified dirll press wear washer test method. Wear factor and coefficient

Mark P. Wolverton; John E. Theberge

1981-01-01

210

Predicting the tensile strength of natural fibre reinforced thermoplastics  

Microsoft Academic Search

The tensile strength of short natural fibre reinforced thermoplastics (NFRT) was modeled using a modified rule of mixtures (ROM) strength equation. A clustering parameter, requiring the maximum composite fibre volume fraction, forms the basis of the modification. The clustering parameter highlights that as fibre loading increases, the available fibre stress transfer area is decreased. Consequently, at high volume fractions this

Angelo G. Facca; Mark T. Kortschot; Ning Yan

2007-01-01

211

New cork powder particleboards with thermoplastic binding agents  

Microsoft Academic Search

A process for the manufacture of cork powder particleboards is described, where the agglomeration of the particles and in some cases the gluing of surface layers, is achieved by using different kinds of thermoplastics such as polyethylene and polyproyplene. Boards obtained by this process possess physico-mechanical characteristics which allow for a wider spectrum of applications than those of currently marketed

Luis Manuel C. C. Gil

1993-01-01

212

Analysis of the friction (spin)welding process for thermoplastics  

Microsoft Academic Search

The friction (spin)-welding process for thermoplastics is known to consist of four phases: (1) initial heating of the interface to the melting temperature by Coulomb friction, (2) unsteady melting and flow in the transverse direction, (3) steady-state flow, and (4) unsteady flow and solidification after the spin motion is stopped. Simple analytical models, which are based on an analysis of

Vijay K. Stokes

1988-01-01

213

Resistance welding of thermoplastic composites-an overview  

Microsoft Academic Search

This paper presents an extensive overview of resistance welding of thermoplastic composites. The objective is to provide a deeper insight into the nature of the resistance welding process and a summary of the vast experimental investigative effort put into it over the years. The main focus is set on the parameters that govern the welding process and the principal phenomena

D. Stavrov; H. E. N. Bersee

2005-01-01

214

Monitoring the resistance welding of thermoplastic composites through acoustic emission  

Microsoft Academic Search

This paper investigates the monitoring of thermoplastic composite's resistance welding through acoustic emission. An amorphous bonding technique (Thermobond TM) is used to join AS4 graphite fiber reinforced polyetheretherketone (APC2). By placing acoustic emission sensors next to the weld region, the influence of welding parameters on the acoustic emission output was determined. Discrete parameters as well as complete waveforms were acquired

Luigi D'Antonio; Claudio Sabatino; Alberto Ortona; John W. Gillespie Jr.

1992-01-01

215

Measurement Parameters of Ultrasonic Oscillatory System during Welding Thermoplastics  

Microsoft Academic Search

In the article the basic problems interfering evolution of automatic-control systems by process ultrasonic welding are analyzed, measurements electric parameters of ultrasonic oscillatory system during welding thermoplastics, directed on search ways raise of strength a welded joint are executed.

A. N. SIivin; A. D. Abramov; D. S. Abramenko

2007-01-01

216

Process Modeling and Optimization of Resistance Welding for Thermoplastic Composites  

Microsoft Academic Search

Resistance welding is a suitable technique for joining thermoplastic composites. Like other fusion bonding processes, it involves heating, melting and cooling steps. Productivity depends on the time that passes during these steps. This is the first study that tries to increase the productivity of the process in a systematic way. The objective of the present study is to determine the

Ziya Seyhan Colak; Fazil Onder Sonmez; Vahan Kalenderoglu

2002-01-01

217

Induction welding of thermoplastic composites—an overview  

Microsoft Academic Search

This paper presents a comprehensive overview of the process of induction welding of thermoplastic composites. The main objective is to provide a deeper insight into the nature of the induction welding process and to summarise the investigative effort that was put into it by a large group of researchers. The main focus is put on the types of heat generation

T. J. Ahmed; D. Stavrov; H. E. N. Bersee; A. Beukers

2006-01-01

218

Thermal Mechanical Testing of Low Density Thermoplastic Foam  

Microsoft Academic Search

Foams made from engineered thermoplastic resin systems possess high glass transition temperatures. When compared to most thermoset resins, it was anticipated that lightly cross-linked foam candidates might survive high temperature\\/ pressure cures. This is especially true if the viscosity decline (i.e., loosening of weak secondary bonds) during sandwich bond cycles were found to be gradual enough to be controllable. To

J. C. Guzman; D. A. McCarville; D. M. Rotter

2009-01-01

219

Deepdrawing FE-simulations for thermoplastic sandwich structures  

Microsoft Academic Search

In this paper deepdrawing FE analyses are performed on full three-dimensional and geometrically detailed thermoplastic sandwich\\u000a plates with honeycomb cores. Forming analyses with bending in one and two directions are conducted. The importance of the\\u000a out-of-plane core shear strength in these deepdrawing processes is pointed out.

C. Macaluso; D. Vandepitte; I. Verpoest

2008-01-01

220

Nonlinear Flexural Deflection of Thermoplastic Foam Core Sandwich Beam  

Microsoft Academic Search

Nonlinear flexural deflection behavior of foam core sandwich beams hasbeen experimentally investigated. The experimental data were compared with the predicted results obtained from a proposed analytical method and the finite element analysis. Sandwich beams with thermoplastic foam core and carbon\\/epoxy fabric faces were manufactured using the vacuum bagging process. To investigate the effect of the face thickness on the nonlinear

Kwang Joon Yoon; C. K. Kim; Hoon C. Park

2002-01-01

221

Mechanical property enhancement of thicker section thermoplastic composites by hybridization  

Microsoft Academic Search

With success of composite materials in high performance structures, new structural applications are being identified. This will require use of thicker section thermoplastic composites. Thick section (16, 40, and 80 plies) hybrid polyphenylene sulfide (PPS) matrix composites were evaluated for tensile, flexural, and compressive response. The hybridization of the composite was achieved by using E glass and AS4 graphite fibers.

Khatri

1990-01-01

222

Cellular thermoplastic composites with microstructural gradients of fibres and porosity  

Microsoft Academic Search

New thermoplastic composites with their composition tailored at the yarn level were proposed and successfully prepared. A specific processing method was developed for composites exhibiting different fibre and porosity concentration gradients. Mechanical properties of such composites were determined by three-point bending tests. In order to carry out investigations on wide ranges of fibre and porosity fractions, a material system based

Manuel Bühler; Pierre-Etienne Bourban; Jan-Anders E. Månson

2008-01-01

223

Material, process, and product design of thermoplastic composite materials  

Microsoft Academic Search

Thermoplastic composites made of polypropylene (PP) and E-glass fibers were investigated experimentally as well as theoretically for two new classes of product designs. The first application was for reinforcement of wood. Commingled PP\\/glass yarn was consolidated and bonded on wood panel using a tie layer. The processing parameters, including temperature, pressure, heating time, cooling time, bonding strength, and bending strength

Heming Dai

2001-01-01

224

A first insight on composites of thermoplastic starch and kaolin  

Microsoft Academic Search

In this work we have studied the utilization of kaolin as filler reinforcement for thermoplastic starch in order to improve its mechanical properties. The composites were prepared with regular cornstarch plasticized with glycerin and reinforced with hydrated kaolin. All the components were pre-mixed and processed in an intensive batch mixer at 170°C. Compounds with 0, 10, 20, 30, 40, 50

A. J. F de Carvalho; A. A. S Curvelo; J. A. M Agnelli

2001-01-01

225

Metal\\/polymer\\/metal hybrid systems: Towards potential formability applications  

Microsoft Academic Search

This paper deals with the development, forming and testing of functional three-layered metal\\/polymer\\/metal sandwich sheets – e.g. for automotive applications – in order to tailor them with particularly demanded properties.The sandwich sheets were produced by roll bonding and heating press processes using austenitic high-grade steel and\\/or aluminium alloy sheets as surface layers. For the cores thermoplastic polymers, with and without

Adele Carradò; Jacques Faerber; Sonja Niemeyer; Gerhard Ziegmann; Heinz Palkowski

2011-01-01

226

Modification of wood fiber with thermoplastics by reactive steam-explosion processing  

NASA Astrophysics Data System (ADS)

For the first time, a novel processing method of co-refining wood and polyolefin (PO) by steam-explosion was scientifically explored for wood-thermoplastic composites without a coupling agent. Traditional studies have addressed the improvement of adhesion between components of wood thermoplastic composites through the use of coupling agents such as maleated PO. The objective of this study was to increase adhesion between wood and PO through reactive processing conditions of steam-explosion. PO characteristics, such as type (polyethylene or polypropylene), form (pellet, fiber, or powder) and melt viscosity were studied along with oxygen gas content of the steam-explosion reactor vessel. Modification of co-processed wood fiber was characterized in four studies: microscopy analysis of dispersion of PO with wood fiber, sorption properties of co-processed material, chemical analysis of fractionated components, and morphological investigation of co-processed material. Two additional studies are listed in the appendices that relate to adsorption of amphiphilic polymers to the cellulose fiber surface, which is one hypothesis of fiber surface modification by co-steam-explosion. Microscopy studies revealed that PO melt viscosity was found to influence the degree of dispersion and uniformity of the steam-exploded material. The hygroscopic nature of the co-processed fiber declined as shown by sorption isotherm data. Furthermore, a water vapor kinetics study found that all co-refined material had increased initial diffusion coefficients compared to the control fiber. Chemical changes in fractionated components were PO-type dependent. Lignin extracted from co-processed wood and polyethylene showed PO enrichment determined from an increase of methylene stretching in the Fourier Transform infrared subtraction spectra, while lignin from co-processed wood and polypropylene did not. Additionally, extracted PO showed indirect signs of oxidation as reflected by fluorescence studies. Solid state nuclear magnetic resonance spectroscopy revealed a number of differences in the co-processed materials such as increased cellulose crystallinity, new covalent linkages and an alternative distribution of components on the nanoscale reflected in the T1rho relaxation parameter. Steam-explosion was shown to modify wood fiber through the addition of "non-reactive" polyolefins without the need for coupling agents. In light of these findings, co-refining by steam-explosion should be viewed as a new reactive processing method for wood thermoplastic composites.

Renneckar, Scott H.

227

Nonlinear rheology and strain recovery of short chain branched polyolefin elastomers and thermoplastic olefin blends  

NASA Astrophysics Data System (ADS)

Polyolefin elastomers are random copolymers having a polyethylene backbone with the higher olefinic comonomer incorporated as short-chain branches. These random copolymers are widely used as polymer modifiers for thermoplastic materials such as polypropylenes, resulting in thermoplastic olefin (TPO) blends. This thesis addresses the nonlinear rheological behavior of the elastomers and then of the TPO blends. The effects of varying short chain branch density (SCB) on the melt rheology of three ethylene-octene random copolymers have been investigated. In particular, the strain-hardening behavior in extensional flow and strain recovery following nonlinear shear creep has been evaluated. The zero-shear viscosity followed trends in the backbone molecular weight closely. While the three copolymers were indistinguishable in linear viscoelastic creep and recovery, recovery following nonlinear shear creep decreased progressively with increasing SCB density. This reveals that the extent of rapid chain equilibration that occurs over Rouse time scales at higher strains was progressively lower with increasing SCB density. Strain hardening in uniaxial extensional flow was observed for all three copolymers. At strain rates below the primitive chain equilibration rates, strain hardening increases progressively with increasing SCB density. At higher rates, upon onset of primitive chain stretch, the strain hardening behavior for the three melts merges. Two thermoplastic olefin (TPO) blends were characterized in the context of injection molding; the surface morphology of injection molded tensile bars with these materials showed surface defects or flow marks to different extents. The flow marks were traced to different degrees of strain recovery in the dispersed phases of the two blends. This recovery occurred over injection molding timescales of the order of a few seconds. Strain recovery after shear creep was higher in the blend that displayed more severe flow marks in injection molding; the corresponding elastomer by itself also showed a greater extent of creep recovery. The quick strain recovery in the elastomer must be associated with elastic stresses rather than interfacial tension. A new experimental apparatus was assembled to study strain recovery after elongation of a model elastomer suspended in a less viscoelastic medium at room temperature. Small drops of well-characterized elastomers suspended in a matrix fluid of lower viscosity and elasticity, are stretched rapidly without wall effects in this setup; the stretch ratio of the drops is then recorded over time. Preliminary results confirm significant recovery over a few seconds. Exploration of the full range of parameters with this setup is left for future work.

Patham, Bhaskar

228

Microinjection moulding of polymer microfluidic devices  

Microsoft Academic Search

Microfluidic devices have several applications in different fields, such as chemistry, medicine and biotechnology. Many research\\u000a activities are currently investigating the manufacturing of integrated microfluidic devices on a mass-production scale with\\u000a relatively low costs. This is especially important for applications where disposable devices are used for medical analysis.\\u000a Micromoulding of thermoplastic polymers is a developing process with great potential for

Usama M. Attia; Silvia Marson; Jeffrey R. Alcock

2009-01-01

229

Impact of Nanotube Addition on Stress Recovery of Thermoplastic Elastomer Nanocomposites.  

NASA Astrophysics Data System (ADS)

Recent extension of polymer nanocomposite concepts to shape memory polymers has demonstrated potential to substantially improve recovery stress and provide novel triggering options, while still maintaining large deformations. One such example is multi wall carbon nanotubes (MWCNT)s in thermoplastic polyurethane (PU), where the MWCNTs increase modulus and modify strain induced crystallization leading to improved strain set and recovery force relative to unfilled PU as well as conventionally-filled PU. The impact of MWCNT alignment on the stress recovery rate depends on MWCNT concentration and the procedure used to `set' the deformation. Differences in response time upon shape recovery are observed whether the nanocomposites are `set' above the melting point of soft segment crystallites or at room temperature (RT). A detailed dynamic mechanical analysis protocol reveals that recovery rate and shape fixity are increasing as a function of MWCNT volume fraction and that RT processed nanocomposites show overall superior results. Recovery times can be described with a modification of the Kohlrausch-Williams-Watt equation, indicating a contribution from elasticity of the carbon nanotubes or chain scission of the matrix PU.

Powers, Daniel; Alexander, Max; Vaia, Richard; Arlen, Michael; Koerner, Hilmar

2006-03-01

230

Microwave facilities for welding thermoplastic composites and preliminary results.  

PubMed

The wide range of applications of microwave technology in manufacturing industries has been well documented (NRC, 1994; Thuery, 1992). In this paper, a new way of joining fibre reinforced thermoplastic composites with or without primers is presented. The microwave facility used is also discussed. The effect of power input and cycle time on the heat affected zone (HAZ) is detailed together with the underlying principles of test piece material interactions with the electromagnetic field. The process of autogenous joining of 33% by weight of random glass fibre reinforced Nylon 66, polystyrene (PS) and low density polyethylene (LDPE) as well as 23.3% by weight of carbon fibre reinforced PS thermoplastic composites is discussed together with developments using filler materials, or primers in the heterogenous joining mode. The weldability dependence on the dielectric loss tangent of these materials at elevated temperatures is also described. PMID:10687151

Ku, H S; Siores, E; Ball, J A

1999-01-01

231

Distribution of Oil in a PP\\/EPDM Thermoplastic Elastomer  

Microsoft Academic Search

Distribution of oil in a commercial PP(polypropylene)\\/EPDM(ethylene-propyrene-diene rubber) thermoplastic elastomer was analyzed by light scattering. It was shown that the oil preferentially stays in EPDM particles at low temperatures and it migrates to PP matrix at high temperatures. That is, the oil is expected to play a dual role; softener at ambient temperature and plasticizer at processing temperature. The temperature

Yutaka Kikuchi; Tetsuo Okada; Takashi Inoue

2009-01-01

232

Poly (butylensuccinate co-adipate)thermoplastic starch nanocomposite blends  

Microsoft Academic Search

Nanocomposites based on blends of thermoplastic corn starch (TPS), plasticized with glycerol, and poly (butylensuccinate co-adipate) (PBAS) were prepared using sodium montmorillonite and organomodified montmorillonite. X-ray diffraction and scanning electron microscopy were used to study the clay dispersion. The effects of PBAS and clay type content on mechanical properties were evaluated. TPS\\/PBAS\\/organic modified montmorillonite shows an exfoliated nanocomposite structure and

S. Bocchini; D. Battegazzore; A. Frache

2010-01-01

233

Distribution of Oil in a PP/EPDM Thermoplastic Elastomer  

NASA Astrophysics Data System (ADS)

Distribution of oil in a commercial PP(polypropylene)/EPDM(ethylene-propyrene-diene rubber) thermoplastic elastomer was analyzed by light scattering. It was shown that the oil preferentially stays in EPDM particles at low temperatures and it migrates to PP matrix at high temperatures. That is, the oil is expected to play a dual role; softener at ambient temperature and plasticizer at processing temperature. The temperature dependence of oil distribution was nicely interpreted by a thermodynamic discussion.

Kikuchi, Yutaka; Okada, Tetsuo; Inoue, Takashi

234

Surface segregation of branched polyethyleneimines in a thermoplastic polyurethane  

Microsoft Academic Search

Hyperbranched polyethyleneimines were modified with methacrylated fluorosurfactants and aliphatic epoxides to provide a library of macromolecules with controlled chain ends and residual amine functionality. These materials were co-dissolved with a thermoplastic polyurethane-ether and the blends were subsequently deposited as films cast from solution. The surface chemistry of the cast films was determined using angle resolved X-ray photoelectron spectroscopy (AR-XPS) and

Joshua A. Orlicki; Wendy E. Kosik; J. Derek Demaree; Matthew S. Bratcher; Robert E. Jensen; Steven H. McKnight

2007-01-01

235

Predicting the elastic modulus of natural fibre reinforced thermoplastics  

Microsoft Academic Search

Natural fibre reinforced thermoplastics (NFRT) are increasingly used in a variety of commercial applications, but there has been little theoretical modeling of structure\\/property relationships in these materials. In this study, micromechanical models available in the short fibre composites literature were used to predict the stiffness of some commercially important natural fibre composite formulations.Also included are equations that correct the Young’s

Angelo G. Facca; Mark T. Kortschot; Ning Yan

2006-01-01

236

Thermostable Insulating Thermoplastic Elastomers from Rubber Polycarbonate Blends  

Microsoft Academic Search

Thermoplastic elastomeric blends based on polycarbonate (PC) (30 parts) and elastomers (70 parts) of varying polarity, e.g., ethylene propylene diene rubber (EPDM), chlorinated polyethylene (CPE), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM) have been studied and characterized by various methods, e.g., stress-strain measurement, surface energy estimation, thermogravimetric analysis, dynamic mechanical analysis and volume resistivity measurement. The highest

Namita Roy Choudhury; Anil K. Bhowmick

1996-01-01

237

Cellulose Fiber\\/Bentonite Clay\\/Biodegradable Thermoplastic Composites  

Microsoft Academic Search

Adding cellulose fiber reinforcement can improve mechanical properties of biodegradable plastics, but fiber must be well dispersed\\u000a to achieve any benefit. The approach to dispersing fiber in this study was to use aqueous gels of sodium bentonite clay. These\\u000a clay-fiber gels were combined with powdered compostable thermoplastics and calcium carbonate filler. The composite was dried,\\u000a twin-screw extruded, and injection molded

C. N. Ludvik; G. M. Glenn; A. P. Klamczynski; D. F. Wood

2007-01-01

238

RESISTANCE WELDING OF THERMOPLASTIC COMPOSITE SKIN\\/STRINGER SPECIMENS  

Microsoft Academic Search

An investigation of resistance welding of thermoplastic composites skin\\/stringer specimens is presented. Skin\\/stringer configurations with square-ended and 20° taper-ended flanges were resistance-welded using a metal mesh heating element. The skin and stringer laminates were made of 16-ply APC-2\\/AS4 PEEK\\/carbon fiber composite. The objective of this work was to study the feasibility of resistance welding to assemble aerospace structures with non-uniform

Martine Dubé; Pascal Hubert; Ali Yousefpour; Johanne Denault

239

Material, process, and product design of thermoplastic composite materials  

NASA Astrophysics Data System (ADS)

Thermoplastic composites made of polypropylene (PP) and E-glass fibers were investigated experimentally as well as theoretically for two new classes of product designs. The first application was for reinforcement of wood. Commingled PP/glass yarn was consolidated and bonded on wood panel using a tie layer. The processing parameters, including temperature, pressure, heating time, cooling time, bonding strength, and bending strength were tested experimentally and evaluated analytically. The thermoplastic adhesive interface was investigated with environmental scanning electron microscopy. The wood/composite structural design was optimized and evaluated using a Graphic Method. In the second application, we evaluated use of thermoplastic composites for explosion containment in an arrester. PP/glass yarn was fabricated in a sleeve form and wrapped around the arrester. After consolidation, the flexible composite sleeve forms a solid composite shell. The composite shell acts as a protection layer in a surge test to contain the fragments of the arrester. The manufacturing process for forming the composite shell was designed. Woven, knitted, and braided textile composite shells made of commingled PP/glass yarn were tested and evaluated. Mechanical performance of the woven, knitted, and braided composite shells was examined analytically. The theoretical predictions were used to verify the experimental results.

Dai, Heming

240

Evaluation of thermoplastic stiffened panels for application to rotorcraft airframes  

NASA Astrophysics Data System (ADS)

An experimental evaluation of thermoplastic skin-stiffener structure was conducted by evaluating the shear strength, impact resistance, and damage tolerance of stiffened panels with thin-gage skins. Seventeen 23.5 x 23.5 inch three-stiffener test panels were manufactured with five skin configurations: 0.020 inch, 0.030 inch, and 0.040 inch thick IM7/APC-2 and 0.030 inch and 0.040 inch thick AS4/APC-2. In low-velocity impact trials, the IM7/APC-2 panels showed much higher impact resistance than the AS4/APC-2 panels, and both thermoplastic configurations showed higher impact resistance than AS4/3501-6 graphite/epoxy panels tested previously. In picture-frame shear tests, the undamaged thermoplastic shear panels suffered buckling-induced stiffener debonding but had failure loads above AS4/3501-6 panels with the same skin thickness. Residual panel strength after impact varied considerably due to variation in the damage states, but all failure loads were equal to or higher than those of the AS4/3501-6 panels. In tests of both undamaged and impacted panels, the failure stresses of the IM7/APC-2 and AS4/APC-2 panels were similar.

Weems, Douglas B.; Llorente, Steven G.

241

40 CFR Table 6 to Subpart Jjj of... - Known Organic HAP Emitted From the Production of Thermoplastic Products  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Known Organic HAP Emitted From the Production of Thermoplastic...Table 6 to Subpart JJJ of Part 63âKnown Organic HAP Emitted From the Production of Thermoplastic... Thermoplastic product/Subcategory Organic HAP/chemical name(CAS No.)...

2013-07-01

242

Formulations for thermoplastic vulcanizates based on high density polyethylene, ethylene-propylene-diene monomer, and ground tyre rubber  

Microsoft Academic Search

Thermoplastic vulcanizates (TPVs) are a specific group of the so called thermoplastic elastomers. The main characteristic is the existence of a crosslinked rubber phase obtained by dynamic vulcanization in the presence of the thermoplastic matrix. This article studies TPVs based on ground tyre rubber (GTR), high-density polyethylene, and ethylene propylene diene monomer rubber. Vulcanization is performed by a new peroxide

J. Cañavate; P. Casas; X. Colom; F. Nogués

2011-01-01

243

A new technique to improve adhesion of polyaramid fibers to thermoplastic  

Microsoft Academic Search

A novel technique is developed to increase interfacial adhesion between organic fibers and thermoplastics. The technique consists of exposing the fiber to a radio-frequency plasma discharge and then immediately coating the fiber with thermoplastic while still in the vacuum environment of the plasma reactor. Increased adhesion is shown using a polyaramid fiber (Kevlar 49) and a polycarbonate resin (Lexan 121).

W. G. Pitt; J. E. Lakenan; A. Brent Strong

1991-01-01

244

Thermal Degradation, Mechanical Properties and Morphology of Wheat Straw Flour Filled Recycled Thermoplastic Composites  

PubMed Central

Thermal behaviors of wheat straw flour (WF) filled thermoplastic composites were measured applying the thermogravimetric analysis and differential scanning calorimetry. Morphology and mechanical properties were also studied using scanning electron microscope and universal testing machine, respectively. Presence of WF in thermoplastic matrix reduced the degradation temperature of the composites. One for WF and one for thermoplastics, two main decomposition peaks were observed. Morphological study showed that addition of coupling agent improved the compatibility between WFs and thermoplastic. WFs were embedded into the thermoplastic matrix indicating improved adhesion. However, the bonding was not perfect because some debonding can also be seen on the interface of WFs and thermoplastic matrix. In the case of mechanical properties of WF filled recycled thermoplastic, HDPE and PP based composites provided similar tensile and flexural properties. The addition of coupling agents improved the properties of thermoplastic composites. MAPE coupling agents performed better in HDPE while MAPP coupling agents were superior in PP based composites. The composites produced with the combination of 50-percent mixture of recycled HDPE and PP performed similar with the use of both coupling agents. All produced composites provided flexural properties required by the ASTM standard for polyolefin-based plastic lumber decking boards.

Mengeloglu, Fatih; Karakus, Kadir

2008-01-01

245

Influence of natural fibers in recycling of thermoplastics for automotive components  

Microsoft Academic Search

Use of natural fiber thermoplastic components in the automotive industry can provide the advantages of weight reduction, cost reduction and recyclability, in addition to eco- efficiency and renewability compared to synthetic conventional materials. Natural fibers have recently become attractive to automotive industry as an alternative reinforcement for glass fiber reinforced thermoplastics. The best way to increase the fuel efficiency with

S. Jeyanthi; J. Jeevamalar; J. Jancirani

2012-01-01

246

High-speed laser cutting of superposed thermoplastic films: thermal modeling and process characterization  

Microsoft Academic Search

Common thermoplastic films used in the packaging industry have a thickness lower than 100?m, and present low absorption to CO2 laser radiation. This characteristic renders the use of cutting parameters, predicted by models developed for thicker thermoplastics inappropriate. In addition, the usual procedures involve the use of an assisting gas, responsible for removing the melted material, which, when processing thin

João M. P. Coelho; Manuel A. Abreu; F. Carvalho Rodrigues

2004-01-01

247

Field Verification of Structural Performance of Thermoplastic Pipe Under Deep Backfill Conditions  

Microsoft Academic Search

This report provides information regarding the structural performance of thermoplastic pipes under relatively deep soil cover conditions. The eighteen (12 HDPE, 6 PVC) thermoplastic pipes, with diameter ranging from 30 to 60 in., were instrumented with sensors, embedded with granular backfill in shallow trenches, and subjected to 20-ft or 40-ft high soil fill for about 10 months. Their installation plans

S. Sargand

2002-01-01

248

Breakdown voltage behavior of PET thermoplastics at DC and AC voltages  

Microsoft Academic Search

The demand on thermoplastic encapsulation of coils and electronic devices has been increased recently as an alternative to thermosets for electrical insulation, heat dissipation and physical protection of the encapsulated devices from harsh environmental operating conditions. Compared with thermosets, thermoplastics offer excellent electrical properties, superior surface hardness, excellent dimensional stability and good chemical and heat resistance. This paper presents a

S. Grzybowski; E. A. Feilat; P. Knight; L. Doriott

1999-01-01

249

Measurement of Parameters and Automatic Selection of Optimal Modes During Ultrasonic Welding of Thermoplastic Materials  

Microsoft Academic Search

Article is devoted to research of changes of electric parameters of ultrasonic oscillatory systems (UOS) during ultrasonic welding of thermoplastic materials. In this article the basic problems interfering development of systems of automatic definition of quality of ultrasonic welding are analyzed. The technique performance researches which are directed on improvement of quality of welded connection at ultrasonic welding of thermoplastic

V. N. Khmelev; A. N. Slivin; R. V. Barsukov; S. N. Tsyganok; I. I. Savin; A. V. Shalunov; S. V. Levin; A. D. Abramov

2006-01-01

250

Modelling component cost in compression moulding of thermoplastic composite and sandwich components  

Microsoft Academic Search

Thermoplastic composite and sandwich materials offer a potential of reducing component weight and improving recyclability while at the same time enhancing process economy through reduced manufacturing cycle time. The economical aspects of compression moulding of three different thermoplastic composite and sandwich material systems are modelled herein and are compared to compression moulding of a thermoset sheet moulding compound and stamping

M. Åkermo; B. T. Åström

2000-01-01

251

NOVEL THERMOPLASTIC FOAM STRUCTURAL CORE MATERIAL WITH ENHANCED THERMOFORMABILITY, FATIGUE ENDURANCE AND ELEVATED TEMPERATURE PROPERTIES  

Microsoft Academic Search

Recent advances in thermoplastic resin chemistry have enabled the development of a thermoplastic polyester foam core material with excellent thermoformability, elevated temperature and chemical resistance, and superior fatigue endurance. Possessing high strength and rigidity, this foam product fulfills the demanding requirements for structural core materials used in sandwich composites, though it can be successfully used without facings for many applications.

Kurt Feichtinger; Wenguang Ma; Tristan Touzot

252

Modeling of Heat Conduction in Thermoplastic Honeycomb Core\\/Face Sheet Fusion Bonding  

Microsoft Academic Search

Honeycomb sandwich materials have been widely used in aerospace industry as secondary structural materials or interior panels. Recently the research of full thermoplastic honeycomb sandwich materials has been of interest due to their recyclability. In their production, they usually demand an adhesive-free process, namely fusion bonding, to connect thermoplastic honeycomb core and face sheets. It is a heat induced process

Fan Xinyu; Li Yubin; Li Juan; Yan Chun; Li Ke

2009-01-01

253

Electroless copper plating and surface characterization of thermoplastic PPO based printed circuit boards  

Microsoft Academic Search

Purpose – The adhesion between electroless copper and a substrate is one of the most important factors in the reliability of thermoplastic printed circuit boards. The purpose of this paper is to investigate the effects of mechanical grinding and acid etching of thermoplastic substrate materials on the adhesion of copper deposited by an electroless copper plating process. The base material

Teija Laine-Ma; Pekka Ruuskanen; Satu Kortet; Mikko Karttunen

2009-01-01

254

A novel high-performance gel polymer electrolyte membrane basing on electrospinning technique for lithium rechargeable batteries  

Microsoft Academic Search

Nonwoven films of composites of thermoplastic polyurethane (TPU) with different proportion of poly(vinylidene fluoride) (PVdF) (80, 50 and 20%, w\\/w) are prepared by electrospinning 9wt% polymer solution at room temperature. Then the gel polymer electrolytes (GPEs) are prepared by soaking the electrospun TPU–PVdF blending membranes in 1M LiClO4\\/ethylene carbonate (EC)\\/propylene carbonate (PC) for 1h. The gel polymer electrolyte (GPE) shows

Na Wu; Qi Cao; Xianyou Wang; Xiaoyun Li; Huayang Deng

255

Rechargeable lithium battery employing a new ambient temperature hybrid polymer electrolyte based on PVK+PVdF–HFP (copolymer)  

Microsoft Academic Search

We describe here for the first time, our recent success in developing an ambient temperature Li+ conducting solid polymer electrolyte (SPE) using the concept of polymer alloying upon blending two thermoplastic polymers such as poly(vinylidene) fluoride-hexafluoropropylene (PVdF–HFP-copolymer) and poly(N-vinylcarbazole), PVK and achieved the room temperature electrolytic conductivity (?i) of 0.7×10?3S\\/cm for a typical composition of PVdF–HFP copolymer\\/PVK blend mixed with

M. S. Michael; S. R. S. Prabaharan

2004-01-01

256

Green technology for conversion of food scraps to biodegradable thermoplastic polyhydroxyalkanoates.  

PubMed

A new technology is developed and demonstrated that couples anaerobic digestion of food scraps with production of biodegradable thermoplastics, polyhydroxyalkanoates (PHAs). The food wastes were digested in an anaerobic reactor producing four major organic acids. The concentrations of acetic, propionic, butyric, and lactic acids reached 5.5, 1.8, 27.4, and 32.7 g/L, respectively. The fermentative acids were transferred through membranes via molecule diffusion into an air-bubbling reactor where the acids were utilized to produce PHAs in an enriched culture of Ralstonia eutropha. With a silicone rubber membrane, butyric acid and small amounts of acetic and propionic acids were transferred and used, producing a homopolymer PHA, poly(3-hydroxybutyrate). The dry cell weight and PHA content reached 11.3 g/L and 60.2% (w/w), respectively. With a dialysis membrane, the mass transfer rates of fermentative acids were enhanced, and the PHA production was significantly improved. The dry cell weight and its PHA content reached 22.7 g/L and 72.6% (w/w), respectively. The formed PHA was a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate (HV) with 2.8 mol % HV monomer unit. The polymer content (72.6% of dry cell mass) reported in this study is the highest one obtained from organic wastes and is comparable with the PHA content from pure glucose fermentation. PMID:12521183

Du, Guocheng; Yu, Jian

2002-12-15

257

Effects of Compression and Filler Particle Coating on the Electrical Conductivity of Thermoplastic Elastomer Composites  

NASA Astrophysics Data System (ADS)

Elastomeric polymers can be filled with metallic micro- or nanoparticles to obtain electrical conductivity, in which the conductivity is largely determined by the intrinsic conductivity of and contact resistance between the particles. Electrons will flow through the material effectively when the percolation threshold for near-neighbor contacts is exceeded and sufficiently close contacts between the filler particles are realized for electron tunneling to occur. Silver-coated glass microparticles of two types (fibers and spheres) were used as fillers in a thermoplastic elastomer composite based on styrene-ethylene-butylene-styrene copolymer, and the direct-current (DC) resistance and radiofrequency impedance were significantly reduced by coating the filler particles with octadecylmercaptan. Not only was the resistance reduced but also the atypical positive piezoresistivity effect observed in these elastomers was strongly reduced, such that resistivity values below 0.01 ? cm were obtained for compression ratios up to 20%. In the DC measurements, an additional decrease of resistivity was obtained by inclusion of ?-extended aromatic compounds, such as diphenylhexatriene. Some qualitative theories are presented to illuminate the possible mechanisms of action of these surface coatings on the piezoresistivity.

Albers, Willem M.; Karttunen, Mikko; Wikström, Lisa; Vilkman, Taisto

2013-10-01

258

SEM evaluation of thermoplastic endodontic materials alterations after disinfection: a new experimental model.  

PubMed

This study assessed a new experimental model to analyze the effects of sodium hypochlorite solution 2.5% for 10 min and chlorhexidine 2% for 15 s on cones surface alterations. Twenty five gutta-percha and 25 thermoplastic synthetic polymer-based cones had their last 1 mm from the tapered end examined by scanning electron microscopy (SEM) before and after being exposed to the disinfectant solutions. To allow the surfaces to be compared, the samples were not metalized, a voltage of 1 kV was used and the images were captured within standardized angles. The samples were immersed on the test solutions. The comparison of the alterations of the cones was performed using the software program Adobe Photoshop CS. A measurement was taken of the standard deviations of the pixel intensity in this area, higher standard deviations represent more irregular areas. Differences in standard deviation before and after disinfection for each cone were compared between groups by means of analysis of variance supplemented by the Tukey test. Gutta-percha cones showed higher standard deviations than Resilon cones (P < 0.001). In the gutta-percha cones, sodium hypochlorite generated more irregular areas than chlorhexidine and the control group (P < 0.001). The present study has demonstrated the feasibility of using a modified SEM method. This opens opportunities to the use of new and precise tools for evaluating a sample in different moments. PMID:21181716

Grecca, Fabiana Soares; Porto, Marcos; Fontanella, Vania Regina Camargo; Scarparo, Roberta Kochenborger

2011-01-01

259

The Preparation and Characterization of Glycerol Pseudo-Thermoplastic Starch\\/Glycerol Pseudo-Thermoplastic Polyvinyl Alcohol (GTPS\\/GTPVA) Biodegradable Films Using the Solution Casting Method  

Microsoft Academic Search

Starch and polyvinyl alcohol (PVA) are non-plasticized biodegradable materials. The purpose of this research was to transform starch and PVA into pseudo-thermoplastic starch (GTPS) and pseudo-thermoplastic PVA (GTPVA). Plasticizer (Glycerol) was used to reduce the molecular chain interactions and the melting temperatures, and then blended them via solution casting to form GTPS\\/GTPVA biodegradable films. Experimental tests evaluate the effect of

Chin-An Lin; Chi-Che Tung

2010-01-01

260

All-thermoplastic nanoplasmonic microfluidic device for transmission SPR biosensing.  

PubMed

Early and accurate disease diagnosis still remains a major challenge in clinical settings. Biomarkers could potentially provide useful tools for the detection and monitoring of disease progression, treatment safety and efficacy. Recent years have witnessed prodigious advancement in biosensor development with research directed towards rapid, real-time, label-free and sensitive biomarker detection. Among emerging techniques, nanoplasmonic biosensors pose tremendous potential to accelerate clinical diagnosis with real-time multiplexed analysis, rapid and miniaturized assays, low sample consumption and high sensitivity. In order to translate these technologies from the proof-of-principle concept level to point of care clinical diagnosis, integrated, portable devices having small footprint cartridges that house low-cost disposable consumables are sought. Towards this goal, we developed an all-polymeric nanoplasmonic microfluidic (NMF) transmission surface plasmon resonance (SPR) biosensor. The device was fabricated in thermoplastics using a simple, single step and cost-effective hot embossing technique amenable to mass production. The novel 3D hierarchical mold fabrication process enabled monolithic integration of blazed nanogratings within the detection chambers of a multichannel microfluidic system. Consequently, a single hard thermoplastic bottom substrate comprising plasmonic and fluidic features allowed integration of active fluidic elements, such as pneumatic valves, in the top soft thermoplastic cover, increasing device functionality. A simple and compact transmission-based optical setup was employed with multiplexed end-point or dual-channel kinetic detection capability which did not require stringent angular accuracy. The sensitivity, specificity and reproducibility of the transmission SPR biosensor was demonstrated through label-free immunodetection of soluble cell-surface glycoprotein sCD44 at clinically relevant picomolar to nanomolar concentrations. PMID:23287840

Malic, Lidija; Morton, Keith; Clime, Liviu; Veres, Teodor

2013-01-04

261

Rapid dissolving polymer compositions and uses therefor  

SciTech Connect

This patent describes a method for imparting anti-misting properties to a fuel suitable for use on turbine and diesel engines comprising: adding to the fuel a rapid dissolving particulate polymer composition in an amount sufficient to substantially eliminate that population of fuel droplets having a diameter of less than about 50 micrometers normally produced when pure fuel is subjected to wind shear, the particles of the polymer composition having a central core consisting of a high molecular weight thermoplastic polymer which imparts viscoelastic properties to a solution of the polymer in the fuel, the central core having clean surfaces and being surrounded by a multilayer shell of an adherent, particulate, coating agent selected from the group consisting of tricalcium phosphate and graphite having a particle size much smaller than that of the central core and having the interstices between the coating agent particles and around the core filled with an inert gas.

O'Mara, D.P.; Hadermann, A.F.; Trippe, J.C.

1988-12-06

262

Unsaturated Carbosilane and Carbosiloxane Polymers Possessing the Reactive Si-C1 Bond.  

National Technical Information Service (NTIS)

The objective of this research has been broadened from simply producing a highly solvent resistant thermoplastic elastomer for military use to producing a polymer backbone that can be used both as an elastomer as well as for other materials. The idea is t...

K. B. Wagener

2000-01-01

263

Proposal of an empirical viscosity model for quality control in the polymer extrusion process  

Microsoft Academic Search

An empirical model to evaluate the viscosities of thermoplastic polymers in the extrusion process for quality control is proposed in this article. The viscosity is calculated from the screw rotation speed, melt temperature, geometric dimensions of the extruder and material constants, which were experimentally determined. Polypropylene (PP) was used in this study to test the effectiveness of the model. Comparing

Z.-L. Chen; P.-Y. Chao; S.-H. Chiu

2003-01-01

264

Temperature dependence of the thermoplastic formability in bulk metallic glasses  

NASA Astrophysics Data System (ADS)

The temperature dependence of the maximum strain a bulk metallic glass (BMG) can undergo in its supercooled liquid state under specified conditions is determined. This formability is measured experimentally over a wide temperature range using Zr35Ti30Cu8.25Be26.75 as an example BMG. When considering five different BMG formers, we found that the formability continuously increases with temperature. This behavior is ubiquitous among BMGs whose crystallization behavior can be described by steady state nucleation and diffusion limited growth. Therefore, in order to maximize the formability during thermoplastic forming of BMGs, the highest processing temperature should be chosen at which crystallization can still be avoided.

Bryn Pitt, E.; Kumar, Golden; Schroers, Jan

2011-08-01

265

Induction Consolidation of Thermoplastic Composites Using Smart Susceptors  

SciTech Connect

This project has focused on the area of energy efficient consolidation and molding of fiber reinforced thermoplastic composite components as an energy efficient alternative to the conventional processing methods such as autoclave processing. The expanding application of composite materials in wind energy, automotive, and aerospace provides an attractive energy efficiency target for process development. The intent is to have this efficient processing along with the recyclable thermoplastic materials ready for large scale application before these high production volume levels are reached. Therefore, the process can be implemented in a timely manner to realize the maximum economic, energy, and environmental efficiencies. Under this project an increased understanding of the use of induction heating with smart susceptors applied to consolidation of thermoplastic has been achieved. This was done by the establishment of processing equipment and tooling and the subsequent demonstration of this fabrication technology by consolidating/molding of entry level components for each of the participating industrial segments, wind energy, aerospace, and automotive. This understanding adds to the nation's capability to affordably manufacture high quality lightweight high performance components from advanced recyclable composite materials in a lean and energy efficient manner. The use of induction heating with smart susceptors is a precisely controlled low energy method for the consolidation and molding of thermoplastic composites. The smart susceptor provides intrinsic thermal control based on the interaction with the magnetic field from the induction coil thereby producing highly repeatable processing. The low energy usage is enabled by the fact that only the smart susceptor surface of the tool is heated, not the entire tool. Therefore much less mass is heated resulting in significantly less required energy to consolidate/mold the desired composite components. This energy efficiency results in potential energy savings of {approx}75% as compared to autoclave processing in aerospace, {approx}63% as compared to compression molding in automotive, and {approx}42% energy savings as compared to convectively heated tools in wind energy. The ability to make parts in a rapid and controlled manner provides significant economic advantages for each of the industrial segments. These attributes were demonstrated during the processing of the demonstration components on this project.

Matsen, Marc R

2012-06-14

266

Heat flow analysis in connection with thermoplastic filament winding  

NASA Astrophysics Data System (ADS)

In thermoplastic filament winding the calculated rate of cooling is found to be in the order of 100000 degr.C/second at the bonding interface. Short range heat flow phenomena are analyzed, and the result provides a simple rule of thumb for practice, together with a winding speed dependant correction for glass and carbon fiber composites. This enables an easy method to calculate the lower temperature limits for the process of continuous welding, as well as the upper temperature limit where resin starved laminates result from excessive resin flow due to heat buildup. The applied model of heat transfer is given in analytical expressions. Calculated results are given in several graphs.

Brage, Anders; Lamrell, Charles

1988-04-01

267

Fatigue performance characterisation of resistance-welded thermoplastic composites  

Microsoft Academic Search

This study investigates the fatigue performance of resistance-welded thermoplastic composites. Lap shear specimens consisting of unidirectional carbon fibre\\/poly-ether-imide (CF\\/PEI), unidirectional carbon fibre\\/poly-ether-ketone-ketone (CF\\/PEKK) and 8-harness satin weave fabric glass fibre\\/poly-ether-imide (GF\\/PEI) composites were resistance-welded using a metal mesh heating element. The specimens were fatigue-tested at various percentages of their static lap shear strengths at a load ratio R=0.1 and frequency

Martine Dubé; Pascal Hubert; Jan N. A. H. Gallet; Darko Stavrov; Harald E. N. Bersee; Ali Yousefpour

2008-01-01

268

ZnO Nanorod Thermoplastic Polyurethane Nanocomposites: Morphology and Shape Memory Performance  

SciTech Connect

The impact of dispersed alkylthiol-modified ZnO nanorods, as a function of rod aspect ratio and concentration, on the shape memory character of a thermoplastic polyurethane with low hard-segment density (LHS-TPU) is examined relative to the enhanced performance occurring for carbon nanofiber (CNF) dispersion. Solution blending resulted in uniform dispersion within the LHS-TPU of the ZnO nanorods at low volume (weight) fractions (<2.9% v/v (17.75% w/w)). Tensile modulus enhancements were modest though, comparable to values observed for spherical nanofillers. Shape memory characteristics, which in this LHS-TPU result when strain-induced crystallites retard the entropic recovery of the deformed chains, were unchanged for these low volume fraction ZnO nanocomposites. Higher ZnO loadings (12% v/v (50% w/w)) exhibited clustering of ZnO nanorods into a mesh-like structure. Here, tensile modulus and shape recovery characteristics were improved, although not as great as seen for comparable CNF addition. Wide angle X-ray diffraction and NMR revealed that the addition of ZnO nanorods did not impact the inherent strain induced crystallization of the LHS-TPU, which is in contrast to the impact of CNFs and emphasizes the impact of interactions at the polymer-nanoparticle interface. Overall, these findings reinforce the hypothesis that the shape memory properties of polymer nanocomposites are governed by the extent to which nanoparticle addition, via nanoparticle aspect ratio, hierarchical morphology, and interfacial interactions, impacts the molecular mechanism responsible for trapping elastic strain.

Koerner, H.; Kelley, J; George, J; Drummy, L; Mirau, P; Bell, N; Hsu, J; Vaia, R

2009-01-01

269

3D thermoplastic elastomer microfluidic devices for biological probe immobilization.  

PubMed

Microfluidics has emerged as a valuable tool for the high-resolution patterning of biological probes on solid supports. Yet, its widespread adoption as a universal biological immobilization tool is still limited by several technical challenges, particularly for the patterning of isolated spots using three-dimensional (3D) channel networks. A key limitation arises from the difficulties to adapt the techniques and materials typically used in prototyping to low-cost mass-production. In this paper, we present the fabrication of thin thermoplastic elastomer membranes with microscopic through-holes using a hot-embossing process that is compatible with high-throughput manufacturing. The membranes provide the basis for the fabrication of highly integrated 3D microfluidic devices with a footprint of only 1 × 1 cm(2). When placed on a solid support, the device allows for the immobilization of up to 96 different probes in the form of a 10 × 10 array comprising isolated spots of 50 × 50 ?m(2). The design of the channel network is optimized using 3D simulations based on the Lattice-Boltzmann method to promote capillary action as the sole force distributing the liquid in the device. Finally, we demonstrate the patterning of DNA and protein arrays on hard thermoplastic substrates yielding spots of excellent definition that prove to be highly specific in subsequent hybridization experiments. PMID:22041708

Brassard, Daniel; Clime, Liviu; Li, Kebin; Geissler, Matthias; Miville-Godin, Caroline; Roy, Emmanuel; Veres, Teodor

2011-10-31

270

Interlaminate Deformation in Thermoplastic Composite Laminates: Experimental-Numerical Correlation  

NASA Astrophysics Data System (ADS)

The interlaminar deformation behaviors of thermoplastic AS4/PEEK composite laminates subjected to static tensile loading are investigated by means of microscopic moiré interferometry with high spatial resolution. The fully threedimensional orthotropic elastic-plastic analysis of interlaminar deformation for the thermoplastic laminates is developed in this paper, and used to simulate the stress-strain curves of tensile experiment for its angle-ply laminates. Under uniaxial tensile loading, the 3D orthotropic elastic-plastic FE analysis and microscopic moiré interferometry of interlaminar deformations are carried out for the [±25]S4 laminates. The quantitative local-filed experimental results of interlaminar shear strain and displacements at freeedge surface of the laminate are compared with corresponding numerical results of the orthotropic elastic-plastic FE model. It is indicated that the numerical tensile stressstrain curves of angle-ply laminates computed with 3D orthotropic elastic-plastic model are agree with experimental results. The numerical interlaminar displacement U and shear strain ?xz are also consistent with the experimental results obtained by moiré interferometry. It is expected the elastic-plastic interlaminar stresses and deformations analysis for the optimal design and application of AS4/PEEK laminates and its structures.

Shen, M.; Tong, J.; Wang, S.; Fang, Y.

2010-06-01

271

Dielectric Characterization of PCL-Based Thermoplastic Materials for Microwave Diagnostic and Therapeutic Applications  

PubMed Central

We propose the use of a polycaprolactone (PCL)-based thermoplastic mesh as a tissue-immobilization interface for microwave imaging and microwave hyperthermia treatment. An investigation of the dielectric properties of two PCL-based thermoplastic materials in the frequency range of 0.5 – 3.5 GHz is presented. The frequency-dependent dielectric constant and effective conductivity of the PCL-based thermoplastics are characterized using measurements of microstrip transmission lines fabricated on substrates comprised of the thermoplastic meshes. We also examine the impact of the presence of a PCL-based thermoplastic mesh on microwave breast imaging. We use a numerical test bed comprised of a previously reported three-dimensional anatomically realistic breast phantom and a multi-frequency microwave inverse scattering algorithm. We demonstrate that the PCL-based thermoplastic material and the assumed biocompatible medium of vegetable oil are sufficiently well matched such that the PCL layer may be neglected by the imaging solution without sacrificing imaging quality. Our results suggest that PCL-based thermoplastics are promising materials as tissue immobilization structures for microwave diagnostic and therapeutic applications.

Aguilar, Suzette M.; Shea, Jacob D.; Al-Joumayly, Mudar A.; Van Veen, Barry D.; Behdad, Nader; Hagness, Susan C.

2011-01-01

272

Polymer nanocomposites based on P3OT, TPU and SWNT: preparation and characterization  

Microsoft Academic Search

Single walled carbon nanotubes (SWNTs) were incorporated in polymer nanocomposites based on poly(3-octylthiophene) (P3OT), thermoplastic polyurethane (TPU) or a blend of them. Thermogravimetry demonstrated the success of the purification procedure employed in the chemical treatment of SWNTs prior to composite preparation. Stable dispersions of SWNTs in chloroform were obtained by non-covalent interactions with the dissolved polymers. Composites exhibited glass transitions,

Glaura G. Silva; H. D. R. Calado; A. W. Musumeci; W. Martens; E. R. Waclawik; R. L. Frost; G. A. George

2006-01-01

273

Polymer nanocomposites based on P3OT, TPU and SWNT: preparation and characterization  

Microsoft Academic Search

Single walled carbon nanotubes (SWNTs) were incorporated in polymer nanocomposites based on poly(3- octylthiophene) (P3OT), thermoplastic polyurethane (TPU) or a blend of them. Thermogravimetry demonstrated the success of the purification procedure employed in the chemical treatment of SWNTs prior to composite preparation. Stable dispersions of SWNTs in chloroform were obtained by non-covalent interactions with the dissolved polymers. Composites exhibited glass

Glaura G. Silva; Hallen D. R. Calado; Anthony W. Musumeci; Wayde Martens; Eric R. Waclawik; Ray L. Frost; Graeme A. George

2009-01-01

274

Oxo-biodegradable carbon backbone polymers – Oxidative degradation of polyethylene under accelerated test conditions  

Microsoft Academic Search

Oxo-biodegradation of carbon-only backbone polymers is receiving ever increasing attention for the practical implications that some re-engineered thermoplastic polymer formulations based on conventional biostable polymeric materials may satisfy in terms of environmental friendliness and acceptance by commodity plastic manufacturers.In this respect, as part of our continuing activity in the area of bioactive polymeric materials for biomedical and environmental applications, we

E. Chiellini; A. Corti; S. D'Antone; R. Baciu

2006-01-01

275

Ambient Temperature Hybrid Polymer Electrolyte Based on Pvk + Pvdf-Hfp for Lithium Batteries  

Microsoft Academic Search

Proposed herein is a new ambient temperature Li+ conducting PVDF-HFP-co-polymer based hybrid polymer electrolyte with polyvinyl carbozole (PVK) as additive. The addition of the latter provides high ambient temperature electrolytic conductivity (sigmai) 0.7 × 10-3S\\/cm with an ionic transference number of 0.6, besides providing the thermoplastic flexibility to the whole matrix. The membrane is found to exhibit a wide electrochemical

M. S. Michael; S. R. S. Prabaharan

2002-01-01

276

A novel composite gel polymer electrolyte for rechargeable lithium batteries  

Microsoft Academic Search

Composite polymer electrolyte (PE) films comprising of thermoplastic polyurethane (TPU) and polyacrylonitrile (PAN) (denoted as TPU–PAN) have been prepared by two different processes. Scanning electron microscope (SEM) of the films reveal the differences in morphology between them. The electrochemical properties of composite electrolyte films incorporating LiClO4–propylene carbonate (PC) were studied. TPU–PAN based gel PE shows high ionic conductivity at room

Han-Hsin Kuo; Wei-Chih Chen; Ten-Chin Wen; A Gopalan

2002-01-01

277

Wear testing and measurement techniques for polymer composite gears  

Microsoft Academic Search

Injection-moulded composite gears using fibre-reinforced thermoplastics often exhibit increased performance compared with those made from unreinforced polymers. In general, materials are chosen on cost or simple performance grounds (such as, nominal flexural modulus or heat deflection temperature).Aspects of the performance of polymeric gears have been studied by a number of workers and efforts have been made to simulate the contact

N. A Wright; S. N Kukureka

2001-01-01

278

Graphene/Polymer Nanocomposites  

NASA Astrophysics Data System (ADS)

Graphite has attracted large attention as a reinforcement for polymers due to its ability to modify electrical conductivity, mechanical and gas barrier properties of host polymers and its potentially lower cost than carbon nanotubes. If graphite can be exfoliated into atomically thin graphene sheets, it is possible to achieve the highest property enhancements at the lowest loading. However, small spacing and strong van der Waals forces between graphene layers make exfoliation of graphite via conventional composite manufacturing strategies challenging. Recently, two different approaches to obtain exfoliated graphite prior to blending were reported: thermal treatment (Schniepp et al., JACS 2006) and chemical modification (Stankovich et al., J Mat Chem 2006). Both start from graphite oxide. We will describe and evaluate these exfoliation approaches and the methods used to produce graphene reinforced thermoplastics, particularly polyester, polycarbonate and polyurethane nanocomposites. Three different dispersion methods - melt blending, solution mixing and in-situ polymerization -- are compared. Characterization of dispersion quality is illustrated with TEM, rheology and in electrical conductivity, tensile modulus and gas barrier property improvement.

Macosko, Chris

2010-03-01

279

Stamping patterns of insulated gold nanowires with self-organized ultrathin polymer films.  

PubMed

A thermal contact transfer technique is presented for the fabrication of nanoscaled to microscaled patterns of polymer-insulated metal structures on ceramic surfaces using metal-coated, thermoplastic stamps. The thermally activated formation of polymer-metal-polymer (PMP) heterostructures occurs spontaneously when a metal-coated thermoplastic stamp is compressed against a ceramic substrate and subsequently heated. The presented technique exploits the dynamics of ultrathin polymer films localized at interfaces and interfacial forces to prompt local reorganization of polymer stamp materials during processing. Intercalation of polymer stamp materials into the metal-substrate interface yields a cohesive polymer layer that binds the metal layer to the substrate. Disproportionate adhesion between the bulk polymer and the polymer layer at the stamp-metal interface leaves a capping layer upon separation of the stamp from the substrate. Here we demonstrate this technique with single use, bilevel polymer stamps which afford transfer of two distinct general products. The transfer of insulated submicrometer wide wires from the raised stamp features affords patterns of trilayered PMP structures with uniform wire dimensions. Concomitant transfer from the recessed stamp features allows fabrication of multilayered PMP architectures with sub-100 nm spacing from microstructured polymer stamps. Thus, patterns with two different insulated nanowire widths are readily fabricated in a single stamping process. A variety of ceramic substrates, thermoplastic materials, and metals can be used; e.g., inexpensive gold-coated CD or DVD media can be used as stamps, where the combination of materials dictates the relative interfacial forces and the processing parameters. PMID:16848472

Helt, James M; Drain, Charles Michael; Bazzan, Giorgio

2006-07-26

280

Wear of tillage tools coated by thermoplastic coatings  

NASA Astrophysics Data System (ADS)

Experiments were carried out to investigate the abrasive wear of tillage tools caused by soil. Low-carbon steel and hardened steel specimens as well as specimens coated by thermoplastic composites were tested. Silicon oxide (SiO2), aluminium oxide (Al2O3), iron, copper and glass fibre were used as filling materials in polyamide (PA6) and polyethylene (PE) coatings. Low-carbon steel was used as substrate. An abrasive wear tester was constructed to simulate the operation of real tillage tools. The relative motion between the test specimens and soil was controlled. PA6 showed promising results, especially if both the concentration and grain size of the additives were carefully selected. The addition of iron and Al2O3 powders to PA6 showed a considerable mitigation in the wear process if their concentrations were controlled to a certain limit.

Ali, Waheed Y.; Ezzat, Fawzy M. H.

1994-04-01

281

Monitoring the resistance welding of thermoplastic composites through acoustic emission  

NASA Astrophysics Data System (ADS)

This paper investigates the monitoring of thermoplastic composite's resistance welding through acoustic emission. An amorphous bonding technique (Thermobond TM) is used to join AS4 graphite fiber reinforced polyetheretherketone (APC2). By placing acoustic emission sensors next to the weld region, the influence of welding parameters on the acoustic emission output was determined. Discrete parameters as well as complete waveforms were acquired through dedicated hardware and software. Results indicate a strong relationship between acoustic phenomena and welding history. Experimental observations show that change in the cumulative representation of some discrete parameters (ring down counts in the case under study) occurs at the glass transition temperature of the PEI that was comolded on the surface of the parts. The ability to correlate AE with process conditions, quality, and performance gives rise to the potential for further automation and control of the resistance welding process through on-line acoustic measurements.

D'Antonio, Luigi; Sabatino, Claudio; Ortona, Alberto; Gillespie, John W., Jr.

282

Polymer blends as high explosive binders  

SciTech Connect

One approach to high-density, high-modulus binders for explosives is to blend low-density, high-modulus polymers with high-density, low-modulus polymers. Improved properties, which miscible pairs theoretically should have, are discussed. Two attempts to achieve miscibility between a high-density fluoropolymer (Kel-F 800) and high-modulus thermoplastics (Lucite 130 and Phenoxy PKHJ) were unsuccessful. These blends are immiscible and their physical properties are additive or not significantly enhanced. Anelastic properties of the blends indicate phase separation by the presence of two glass transitions, one associated with each phase. Unfortunately, neither of these pairs has merit as an improved plastic-bonded explosive binder. However, a compatible (miscible) pair would be an improved binder if the appropriate polymer pair could be found.

Hoffman, D.M.; Caley, L.E.

1984-10-05

283

EXPERIMENTAL IDENTIFICATION OF FATIGUE DAMAGE MODEL FOR SHORT GLASS FIBRE REINFORCED THERMOPLASTIC COMPOSITES  

Microsoft Academic Search

A polycyclic fatigue damage model for short glass fibre reinforced thermoplastics is developed and implemented into ABAQUS FE code using UMAT subroutine. The MNL model is introduced here in terms of damage rates:

H. Nouri; H. Chalal; F. Meraghni; P. Lory

284

Influence of Molecular Weight on the Mechanical Performance of a Thermoplastic Glassy Polyimide.  

National Technical Information Service (NTIS)

Mechanical Testing of an advanced thermoplastic polyimide (LaRC-TM-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The physical characterization, elastic properties and notch...

L. M. Nicholson K. S. Whitley T. S. Gates J. A. Hinkley

1999-01-01

285

Laboratory Tests of Thermoplastic Piping Assemblies Subjected to Water Hammer and Intermittent Hot Water Flow.  

National Technical Information Service (NTIS)

Evaluation procedures are described that were used at the National Bureau of Standards (NBS) for simulating the long-term effects of water hammer (shock pressure) and cycle hot water flow (thermal cycling) on chlorinated polyvinyl (CPVC) thermoplastic pre...

D. E. Rorrer J. R. Shaver R. S. Wyly

1977-01-01

286

Termoplast- eller Haerdplastkompositer i Flygplanstillaempningar (Thermoplastic or Thermosetting Composites in Aircrafts).  

National Technical Information Service (NTIS)

This report discusses the differences in production processing and performance between thermosetting and thermoplastic fiber reinforced composites, and contains the results of a survey of the opinions of the aerospace industry, research institutes and mat...

O. Dickman F. Larsson

1993-01-01

287

Processing and Characterization of Welded Bonds between Thermoset and Thermoplastic Composites.  

National Technical Information Service (NTIS)

To assemble complex structures with short cycle times, the feasibility of welding thermoplastic (TP) to thermoset (TS) composites is demonstrated using a phenomenological approach. The effect of the thermal degradation of the TS composite (AS4/3501-6) on ...

S. H. McKnight B. K. Fink V. Monnard P. Bourban J. E. Manson

2001-01-01

288

Thermal Bonding of Thermoplastic Composites: Influence of Matrix and Interlayer on the Weld Fracture Toughness.  

National Technical Information Service (NTIS)

The various factors influencing the toughness of welded joints in thermoplastic composites are investigated. Three factors are identified as having a positive influence on weld quality. The use of an interlayer which creates fiber migration in the joint z...

B. Goffaux I. Verpoest

1990-01-01

289

Effects of Repair Processing on the Mechanical Properties of Thermoplastic Matrix Composites.  

National Technical Information Service (NTIS)

Issues relating to the repair of thermoplastic matrix composite materials are investigated. The effects of rapid heating and cooling cycles, typical of most remelting repair processes, on the crystalline morphology and interlaminar fracture toughness of A...

S. V. Hoa X. R. Xiao

1992-01-01

290

Evaluation of Cold Plastic and Hot Spray Thermoplastic on I-20 in Scott County.  

National Technical Information Service (NTIS)

Pavement marking materials exhibit great variation in reflectance values and durability. Hot spray thermoplastic is manufactured in place on the roadway and its quality depends on accurate blending, temperature control and thickness. Cold plastics vary by...

G. R. Gatlin

1993-01-01

291

Shrinking Polymers  

NSDL National Science Digital Library

In this activity, learners discover that some plastics will shrink when you get them hot. Learners bake polystyrene in a regular oven and discover what happens. Safety note: Learners need an adult's help for this activity! Use this activity to talk about different types of plastics such as thermoplastics and thermosets.

Foundation, Polymer S.

2004-01-01

292

Synthesis of well-defined polymer architectures by successive catalytic olefin polymerization and living\\/controlled polymerization reactions  

Microsoft Academic Search

Polyolefins account for more than half of worldwide production of thermoplastics. The majority is used as commodity polymers but they may also provide the starting backbones for original architectures. Most polyolefins are obtained by catalytic polymerization and this powerful technique may be used to produce polyolefins incorporating interesting functional groups that can serve as initiating sites for other successively applied

Ricardo Godoy Lopez; Franck D’Agosto; Christophe Boisson

2007-01-01

293

Chelating efficiency and thermal, mechanical and decay resistance performances of chitosan copper complex in wood–polymer composites  

Microsoft Academic Search

Wood–polymer composites (WPC) have been extensively used for building products, outdoor decking, automotive, packaging materials, and other applications. WPC is subject to fungal and termite attacks due to wood components enveloped in the thermoplastic matrix. Much effort has been made to improve decay resistance of WPC using zinc borate and other chemicals. In this study, chitosan copper complex (CCC) compounds

John Z. Lu; Xinfang Duan; Qinglin Wu; Kun Lian

2008-01-01

294

Modification of wood fiber with thermoplastics by reactive steam-explosion processing  

Microsoft Academic Search

For the first time, a novel processing method of co-refining wood and polyolefin (PO) by steam-explosion was scientifically explored for wood-thermoplastic composites without a coupling agent. Traditional studies have addressed the improvement of adhesion between components of wood thermoplastic composites through the use of coupling agents such as maleated PO. The objective of this study was to increase adhesion between

Scott H. Renneckar

2004-01-01

295

Morphology and performance of unsaturated polyester nanocomposites modified with organoclay and thermoplastic polyurethane  

Microsoft Academic Search

Unsaturated polyester (UPR)\\/thermoplastic polyurethane (TPU)\\/organoclay nanocomposites were prepared by melt compounding of\\u000a thermoplastic polyurethane and unsaturated polyester prepolymer, and then mixing with the hybrids of styrene monomers and\\u000a organoclay at ambient temperature. The crosslinking reaction eventually occurred through the unsaturated polyester prepolymer\\u000a and styrene monomer. The morphology of the composites was investigated by scanning electron microscopy (SEM) and transmission\\u000a electron

Chang-jiang You; Jin-guo Xu; Yi-zheng Zeng; Yao Li; De-min Jia; Toshio Nishi

2010-01-01

296

FIBER LENGTH DISTRIBUTION MEASUREMENT FOR LONG GLASS AND CARBON FIBER REINFORCED INJECTION MOLDED THERMOPLASTICS  

SciTech Connect

Procedures for fiber length distribution (FLD) measurement of long fiber reinforced injection molded thermoplastics were refined for glass and carbon fibers. Techniques for sample selection, fiber separation, digitization and length measurement for both fiber types are described in detail. Quantitative FLD results are provided for glass and carbon reinforced polypropylene samples molded with a nominal original fiber length of 12.7 mm (1/2 in.) using equipment optimized for molding short fiber reinforced thermoplastics.

Kunc, Vlastimil [ORNL; Frame, Barbara J [ORNL; Nguyen, Ba N. [Pacific Northwest National Laboratory (PNNL); TuckerIII, Charles L. [University of Illinois, Urbana-Champaign; Velez-Garcia, Gregorio [Virginia Polytechnic Institute and State University

2007-01-01

297

Mechanical properties and enzymic degradation of thermoplastic and granular sago starch filled poly(?-caprolactone)  

Microsoft Academic Search

The mechanical, morphological and biodegradation properties of two types of poly(?-caprolactone)\\/sago starch (PCL\\/sago) composites were investigated i.e. dried granulated sago starch and undried thermoplastic sago starch (TPSS). Thermoplastic starch was extruded with a twin screw extruder model Haake Rheomix (TW100 attached to a Haake Rheometer (Haake Rheodrive 5000). The composites were compounded with a Haake internal mixer (Haake Rheomix 3000)

K. W Pang; W. S Lee; Z. A. Mohd Ishak

2002-01-01

298

Preparation and properties of thermoplastic honeycomb core sandwich structure with aluminum skin  

Microsoft Academic Search

The low-velocity impact response of thermoplastic honeycomb core sandwich structure with aluminum skin has been investigated by conducting drop-weight impact tests using an instrumented drop-weight impact tower. At first, the shear modulus of the thermoplastic honeycomb core and flexural modulus of the skin were investigated through a series of flexural test. Later in the study, the indentation test was conducted

S. Nurashikin; Akil Hazizan

2012-01-01

299

Characterization of the morphology of co-extruded, thermoplastic\\/rubber multi-layer tapes  

Microsoft Academic Search

Tapes with alternating semi-crystalline thermoplastic\\/rubber layers with thicknesses varying from 100nm up to several ?m were prepared by multi-layer co-extrusion. The variation in layer thickness was obtained by varying the thermoplastic\\/rubber feed ratio. A systematic study on the use of various microscopy techniques to visualize the morphology of the layered systems is presented. The relatively large length scales and the

R. M. A. l’Abee; A. M. J. T. Vissers; J. G. P. Goossens; A. B. Spoelstra; M. van Duin

2009-01-01

300

Preparation and rheological behavior of polymer-modified asphalts  

NASA Astrophysics Data System (ADS)

Different materials and methods were used to prepare and stabilize polymer-modified asphalts. Addition of thermoplastic elastomers improved some technically important properties of asphalt. Due to inherent factors like large density difference between asphalt and polyethylene, many physical methods in which the structure of asphalt is unchanged, failed to stabilize this system. The effect of addition of copolymers and a pyrolytic oil residue derived from used tire rubber were also studied and found to be ineffective on the storage stability of the polymer-asphalt emulsions while high and moderate temperature properties of the asphalt were found to be improved. Finally, the technique of catalytic grafting of polymer on the surface of high-density particles (e.g. carbon black) was used to balance the large density difference between asphalt and polymer. The resulting polymer-asphalts were stable at high temperatures and showed enhanced properties at low and high temperatures.

Yousefi, Ali Akbar

1999-09-01

301

Processing and evaluation of long fiber thermoplastic composite plates for internal fixation  

NASA Astrophysics Data System (ADS)

The metallic plates used in internal fracture fixation may have up to ten times the elastic modulus of normal bone tissue, causing stress shielding-induced osteopenia in healed bone that can lead to re-fracture after plate removal and prolonged and painful recovery. Thermoplastic polymer matrix composites reinforced with long carbon fiber are promising alternative materials for internal fixation plates because they may be produced with relative ease and be tailored to have specific mechanical properties, alleviating the stress shielding problem. Long carbon fiber-reinforced polyetheretherketone (LCF PEEK) plates were produced using the extrusion / compression molding process. Static flexural testing determined that LCF PEEK plates with rectangular cross-section had an average flexural modulus of 12 GPa, or 23% of the flexural modulus of a stainless steel plate. The LCF PEEK plates also experienced negligible (14.7%, 14.5%, and 16.7%) reductions in modulus after fatigue testing at applied moments of 2.5, 3.0, and 3.5 N•m, respectively, over 106 load cycles. Aging the plates in 0.9% NaCl solution for four and eight weeks caused 0.34% and 0.28% increases in plate mass, respectively. No significant decrease of flexural properties due to aging was detected. Differential scanning calorimetry (DSC) revealed the PEEK matrix of the plates to be 24.5% crystalline, which is lower than typical PEEK crystallinity values of 30-35%. Scanning electron microscopy (SEM) revealed three times as many fiber pullout areas in LCF PEEK fracture surfaces as in fracture surfaces of long carbon fiber-reinforced polyphenylenesulfide (LCF PPS), another plate material tested. DSC and SEM data suggest that improvements in processing conditions and fiber/matrix bonding, along with higher carbon fiber fractions, would enhance LCF PEEK plate performance. LCF PEEK remains a promising alternative to stainless steel for internal fixation plates.

Warren, Paul B.

302

LDRD final report on intelligent polymers for nanodevice performance control  

SciTech Connect

A variety of organic and hybrid organic-inorganic polymer systems were prepared and evaluated for their bulk response to optical, thermal and chemical environmental changes. These included modeling studies of polyene-bridged metal porphyrin systems, metal-mediated oligomerization of phosphaalkynes as heteroatomic analogues to polyacetylene monomers, investigations of chemically amplified degradation of acid- and base-sensitive polymers and thermally responsive thermoplastic thermosets based on Diels-Alder cycloaddition chemistry. The latter class of materials was utilized to initiate work to develop a new technique for rapidly building a library of systems with varying depolymerization temperatures.

JAMISON,GREGORY M.; LOY,DOUGLAS A.; WHEELER,DAVID R.; SAUNDERS,RANDALL S.L; SHELNUTT,JOHN A.; CARR,MARTIN J.; SHALTOUT,RAAFAT M.

2000-01-01

303

Development of new near-infrared filters based on the "sandwich" polymer-chalcogenide glass-polymer composites  

NASA Astrophysics Data System (ADS)

A new generation of filters are presented that are ideal for blocking visible light while passing near-infrared radiation. These filters are based on the novel use of selenium-based chalcogenide glasses with a low softening point on the one hand, and thermoplastic polymers on the other hand. A technology was developed that allows `sandwich' structures to be obtained, which include thin layers of polymers and chalcogenide glasses. The technology permits the cutoff edge of filters to be controlled with high accuracy. This can be done either by varying components of the `sandwich' or by varying the thickness of the chalcogenide glass layer.

Bormashenko, Edward; Pogreb, Roman; Pogreb, Zosya; Sutovski, Semion

2001-05-01

304

Processes for Dispersing Single Wall Carbon Nanotubes in Polymers and How to Determine Their Spatial and Alignment Distributions  

Microsoft Academic Search

We are currently designing and making polymer nanocomposites with single wall carbon nanotubes (SWNT) to obtain improved mechanical properties, electrical conductivity, flammability, and thermal conductivity. Our coagulation method is broadly applicable to nanocomposites using readily-soluble thermoplastics such as polystyrene and poly (methyl methacrylate). A variation of this method has been developed for nanotube\\/polymer composites based on high-density polyethylene. Nylon-based composites

Karen I. Winey

2006-01-01

305

Thermal imaging technique to characterize laser light reflection from thermoplastics  

NASA Astrophysics Data System (ADS)

Characterization of laser light reflection during the laser transmission welding (LTW)3Abbreviations: LTW—laser transmission welding, CB—carbon black, IR—infrared, NPFD—normalized power flux distribution of thermoplastics is especially important for applications in which non-zero laser incidence angles are used. At higher laser incidence angles, reflection increases and has the potential to burn surrounding features of the part to be welded. This study presents and validates a technique for laser reflection measurement. Reflected energy is absorbed by a black plastic plate (containing carbon black, which is the absorber of the reflected energy). The surface temperature of the plate is measured by an infrared (IR) camera. The distribution of reflected power required to generate this temperature profile is estimated using a simple heat transfer model. The technique was validated by irradiating the black plate by the laser directly, while observing the time-varying temperature distribution of the plate by the IR camera. In this case, good agreement was observed between the estimated total power and the actual laser input power. Good agreement also existed between the estimated power distribution and that determined experimentally via a knife edge based beam profiling technique. The thermal imaging technique was subsequently used to measure the magnitude and distribution of laser light reflection from unreinforced nylon 6.

Azhikannickal, Elizabeth; Bates, Philip J.; Zak, Gene

2012-07-01

306

Design and testing of novel piezoceramic modules for adaptive thermoplastic composite structures  

NASA Astrophysics Data System (ADS)

For the series production of adaptive fibre-reinforced thermoplastic structures, the development of process-adapted piezoceramic modules is gaining central importance. Therefore, thermoplastic-compatible piezoceramic modules (TPMs) are being developed which are suitable for a matrix-homogeneous adhesive-free integration of the modules in fibre-reinforced thermoplastic structures during a sequential hot-pressing process. Extensive numerical and experimental studies are available on the systematic development of the TPMs, whose thermoplastic carrier film, made, respectively, of polyetheretherketone (PEEK) or polyamide (PA), is already adapted to the matrix material of a thermoplastic composite structure and thus can be joined in a welding process without additional adhesives. The studies carried out indicate the influence of geometrical and technological parameters on the efficiency of consolidated and polarized TPMs and can thus be used to adapt the design specifications and process parameters of the TPMs. Besides these studies, a numerically based residual stress analysis shows the potential for a defined inducing of residual stresses in the TPM components.

Hufenbach, W.; Gude, M.; Heber, T.

2009-04-01

307

Thermoplastic polymer nanocomposites with montmorillonite-Lab vs industrial scale fabrication  

NASA Astrophysics Data System (ADS)

Fabrication of polypropylene or polyamide-6/montmorillonite nanocomposites in a laboratory- and industrial-scale by melt processing has been described. Depending on the fabrication scale, different technological problems were observed that need to be taken into account during production of PP and PA-6-based nanocomposites with MMT which constitute a promising class of modern materials for engineering and packaging applications. Fabrication of PP and PA-6 nanocomposites with montmorillonite both on laboratory and industrial scale needs to be optimized in terms of processing conditions that include pre-mixing parameters, feeding rate, temperature of the barrel zone and extrusion die, screw speed and head pressure. Proper cleaning procedures need to be applied and the selection of the 'main' fraction enables to get nanostructured materials with enhanced properties.

Giacomelli, M.; Pielichowski, K.; Leszczy?ska, A.

2012-09-01

308

The pressure-flow characteristic of circular molding channels with a nonisothermal flow of thermoplastic polymers  

NASA Astrophysics Data System (ADS)

The article contains results of a numerical investigation of the presure-flow characteristic of high-viscosity flows for different rates of heat transfer with the environment. The effect of nonmonotonicity of the characteristic ?P(Vo) on the stability of operation of the die head of extrusion apparatus is discussed.

Ul'Ev, L. M.

1996-07-01

309

Theoretical investigations of continuous ultrasonic seam welding of thermoplastic polymers and fabrics  

Microsoft Academic Search

The article presents results of theoretical investigations of formation of continuous joint in contact area of flat surface of the radiator with rotating surface of the pressure roller. The recommendation on the choice of pressure roller parameters and optimal amplitude of ultrasonic vibrations and broach speed for materials different in properties and thickness were developed on the basis of analysis

Vladimir N. Khmelev; Aleksey N. Slivin; Andrey V. Lehr; Aleksey D. Abramov

2010-01-01

310

Tensile and Impact Properties of Thermoplastic Natural Rubber Reinforced Short Glass Fiber and Empty Fruit Bunch Hybrid Composites  

Microsoft Academic Search

Thermoplastic natural rubber (TPNR) hybrid composite with short glass fiber (GF) and empty fruit bunch (EFB) fiber were prepared via the melt blending method using an internal mixer type Thermo Haake 600p. The TPNR were prepared from natural rubber (NR), liquid natural rubber (LNR) and polypropylene (PP) thermoplastic, with a ratio of 20:10:70. The hybrid composites were prepared at various

H. Anuar; S. H. Ahmad; R. Rasid; N. S. Nik Daud

2006-01-01

311

Sandwichelement med Termoplastmatris foer Lastbaerande Mikrovagsfoenster: Hallfasthetsegenskaper (Sandwich Element with Thermoplastic Matrix for Load Carrying Microwave Windows: Mechanical Properties).  

National Technical Information Service (NTIS)

The aim of the reported work is to manufacture a sandwich element with honey-comb core and facings of fiber reinforced thermoplastics. The problem has been solved by bonding purchased components with an adhesive thermoplastic film. The bonding was perform...

F. Larsson

1998-01-01

312

The effect of glycerol\\/sugar\\/water and sugar\\/water mixtures on the plasticization of thermoplastic cassava starch  

Microsoft Academic Search

The use of 2wt% sugars as co-plasticizer in combination with glycerol was investigated for thermoplastic starch (TPS) from cassava. The results were compared to those for whole cassava root TPS, which naturally contains sugars in the same proportion. The main objective was to investigate the influence of natural sugars present in the cassava root on the properties of thermoplastic starch

E. M. Teixeira; A. L. Da Róz; A. J. F. Carvalho; A. A. S. Curvelo

2007-01-01

313

SUPER HARD SURFACED POLYMERS  

SciTech Connect

High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

Mansur, Louis K [ORNL; Bhattacharya, R [UES, Incorporated, Dayton, OH; Blau, Peter Julian [ORNL; Clemons, Art [ORNL; Eberle, Cliff [ORNL; Evans, H B [UES, Incorporated, Dayton, OH; Janke, Christopher James [ORNL; Jolly, Brian C [ORNL; Lee, E H [Consultant, Milpitas, CA; Leonard, Keith J [ORNL; Trejo, Rosa M [ORNL; Rivard, John D [ORNL

2010-01-01

314

Characteristics of denture thermoplastic resins for non-metal clasp dentures.  

PubMed

Six thermoplastic resins and conventional acrylic resin were examined to characterize their mechanical and physical properties, water sorption, solubility, flexural strength, modulus of elasticity, tensile strength and color stability. Thermoplastic resins for non-metal clasp dentures exhibiting low water sorption and solubility offer hygienic advantages. Since they have a low modulus of elasticity and are easily manipulated, these materials make it possible for larger undercuts to be used for retention compared to acrylic resin. Not all of the thermoplastic resins tested fractured after the bending test in contrast to the conventional denture base resin, which fractured when tested beyond its proportional limit. It was also found that clinically noticeable staining may occur on the polyamide resins and polyethylene terephtalate resins. PMID:20644329

Takabayashi, Yota

2010-07-13

315

A new technique to improve adhesion of polyaramid fibers to thermoplastic  

SciTech Connect

A novel technique is developed to increase interfacial adhesion between organic fibers and thermoplastics. The technique consists of exposing the fiber to a radio-frequency plasma discharge and then immediately coating the fiber with thermoplastic while still in the vacuum environment of the plasma reactor. Increased adhesion is shown using a polyaramid fiber (Kevlar 49) and a polycarbonate resin (Lexan 121). An oxygen-plasma exposure of 4.1 seconds at 24 watts increased interfacial shear strength by 18 percent as evaluated using the critical-filament-length technique. The plasma exposure had no measurable effect on the filament tensile strength or the surface roughness. It is thought that the enhanced adhesion is due to the presence of covalent bonds formed at the interface when free radicals on the fiber are quenched by the thermoplastic. 16 refs.

Pitt, W.G.; Lakenan, J.E.; Strong, A.B. (Brigham Young University, Provo, UT (USA))

1991-07-01

316

Adhesion study of thermoplastic polyimides with Ti-6Al-4V alloy and PEEK-graphite composites  

SciTech Connect

High glass transition (e.g. 360C) melt processable thermoplastic polyimide homopolymers and poly(imide-siloxane) segmented copolymers were prepared from a number of diamines and dianhydrides via solution imidization, polydimethylsilxane segment incorporation and molecular weight control with non-reactive phthalimide end-groups. The adhesive bond performance of these polyimides was investigated as a function of molecular weight, siloxane incorporation, residual solvent, test temperature, and polyimide structure via single-lap shear samples prepared from treated Ti-6Al-4V alloy adherends and compression-molded film adhesives of scrim-cloth adhesives. The adhesive bond strengths increased greatly with siloxane-segment incorporation at 10, 20 and 30 wt% and decreased slightly with total polymer molecular weight. As the test temperature was increased, adhesive bond strength increased, decreased or showed a maximum at some temperatures depending on the polyimide structure and siloxane content. The poly(imide-30% siloxane) segmented copolymer and a miscible poly(ether-imide) also demonstrated excellent adhesive bond strength with poly(arylene ether ketone) PEEK{reg sign}-graphite composites.

Yoon Taeho.

1991-01-01

317

Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.  

PubMed

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. PMID:24094186

Mi, Hao-Yang; Salick, Max R; Jing, Xin; Jacques, Brianna R; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

2013-08-02

318

Microcellular wood-fibre thermoplastic composites: Processing-structure-properties  

NASA Astrophysics Data System (ADS)

In this study, processing-structure-property relationships in foamed wood-fibre plastic composites made with a physical blowing agent were investigated. For the polymers studied, it was found that the crystallinity and morphology have a critical effect on the foaming process. Therefore, an investigation of both semicrystalline and amorphous polymers was conducted. Several amorphous and semicrystalline polymers were selected, based on preliminary experimental results. By non-isothermal crystallisation of the semicrystalline polymers at various cooling rates, specimens with different crystallinities and crystal morphologies were made. The microstructures and sorption properties of these specimens were studied. All the specimens were foamed in a batch process using carbon dioxide as blowing agent and their structures were, investigated. The results showed a great influence of crystallinity and morphology on the solubility and diffusivity of the blowing agent in and through the polymer and especially on the cellular structure of the resulting foams. In contrast to the work of Colton (1989), who suggested that the foaming process should be conducted at a temperature above the melting point, it was shown that by controlling the crystallinity and crystal morphology it is feasible to produce microcellular foams from semicrystalline polymers in the solid state. In the second phase of the study, high density polyethylene and polystyrene were used as the matrices in a foamed wood-fibre composite. Sheets of composites were produced by compounding polymers and fibre. These samples were saturated with carbon dioxide at high pressure and the saturated specimens were foamed at elevated temperatures. Structural analysis and characterisation were performed on both foamed and unfoamed samples. The experimental results showed that the addition of wood fibre had very different effects on the mechanical properties of polystyrene (a glassy polymer) and polyethylene (a semicrystalline ductile polymer). Fibres acted as nucleating agents in the crystallisation of the matrix, and drastically changed the morphology. The impact strength of PS increased when wood fibres were added, while wood fibre diminished the impact strength of PE. The presence of wood fibres significantly changed the microstructure of the composite in the foaming process. Overall, while diminishing the tensile properties (strength and modulus), foaming caused a significant improvement of impact strength of the wood-fibre composites.

Doroudiani, Saeed

319

Interfacial studies in fiber-reinforced thermoplastic-matrix composites  

SciTech Connect

The major theme of this dissertation is structure/property relationships in fiber-reinforced thermoplastic-matrix composites. Effort has been focused on the interface: interfacial crystallization and fiber/matrix adhesion. Included are investigations on interfacial nucleation and morphology, measurement of fiber/matrix adhesion, effects of interfacial adsorption and crystallization on fiber/matrix adhesion, and composites reinforced with thermotropic liquid crystal copolyester fibers. Crystallization of a copolyester and polybutylene terephthalate with glass, carbon, or aramid fibers has been studied with regard to interfacial morphology. Techniques employed included hot-stage optical microscopy and differential scanning calorimetry. Nucleation by the fibers was found to be a general phenomenon. Morphology could be varied by changing the cooling rate. In order to better monitor fiber /matrix adhesion, a buckled plate test has been developed. The test measures transverse toughness as the parameter characterizing interfacial adhesion in unidirectional, continuous-fiber composites. The test is simple to perform yet has advantages over other interfacial evaluation techniques. The buckled plate test was found to be a sensitive measure of fiber/matrix adhesion. The buckled plate test has been used along with the transverse tensile test to examine how interfacial adsorption and crystallization affect fiber/matrix adhesion in polycarbonate/carbon fiber composites. Adsorption was found to be of primary importance in developing adhesion, while crystallization is a secondary effect. The toughness data have been fit successfully for annealing time and temperature dependence. The dependence of adsorption and transverse toughness on matrix molecular weight was found to be large, with higher molecular weights adsorbing more effectively.

Brady, R.L.

1989-01-01

320

Characterization of glass-filled engineering thermoplastic composites  

SciTech Connect

Characterization of three engineering thermoplastic (TP) materials has been carried out to assess suitability for Mound applications: Poly(etheretherketone) (PEEK), Poly(etherimide) (PEI), and Poly(ethersulfone) (PES). Analyses included: thermogravimetric (TG), thermomechanical (TMA), direct probe/mass spectroscopy (DIP/MS), Fourier transform infrared spectroscopy (FT-IR), and other chemical analyses. Both neat and glass-filled PEEK and PES were studied; only unfilled PEI was examined. Thermogravimetric analysis of the three TP's in N/sub 2/ showed that all were greater than or equal to 525/sup 0/C in decomposition onset temperature, with PEEK > PEI > PES. Both glass-filled PEEK and PEI showed <1% weight loss in the melt after two hours (N/sub 2/). TMA analyses were used to determine expansion coefficients below T/sub g/ for all three TP's. The glass-filled PEEK exhibited a low temperature (approx. 60 to 70/sup 0/C) transition below T/sub g/ (approx. 150/sup 0/C) on the first TMA runs. This disappeared on subsequent TMA runs and did not reappear on aging/RT. DIP/MS analyses showed both water and phenyl sulfone to be present in PES and PEEK. Water only was observed in PEI. The presence of phenylsulfone in PEEK was confirmed by FT-IR, and sulfur was found to be present in amounts up to 0.23% in 30% glass-filled molding compounds. Residual polymerization solvent is a probable source. Fluoride (from a monomer in the PEEK polymerization) was also detected.

Whitaker, R.B.; Nease, A.B.; Yelton, R.O.

1983-01-01

321

Dynamic viscoelasticities for short fiber-thermoplastic elastomer composites  

SciTech Connect

Dynamic moduli, E[prime] and E[double prime], and loss tangent tan [delta] were investigated for thermoplastic elastomers (TPEs), styrene-isoprene-styrene copolymers (SISs), styrene-butadiene-styrene copolymer (SBS), and Hytrel and composites reinforced by poly(ethylene terephthalate) (PET) short fibers. The styrenic TPEs have a typical rubbery behavior and the Hytrel TPE has medial characteristics between rubber and plastic. Both E[prime] and E[double prime] of the composites depended on the matrix as well as the fiber loading and fiber length. Based on the viewpoint of different extensibility between the fiber and the matrix elastomer, a triblock model was considered for estimating the storage modulus of the short fiber-TPE composites as follows: E[sub c] = [alpha] V[sub f]E[sub f] + [beta](1 [minus] V[sub f])E[sub m], where [alpha] and [beta] are the effective deformation coefficients for the fiber and the matrix elastomer, respectively. They can be quantitatively represented by modulus ratio M (= E[sub m]/E[sub f]) and fiber length L: [alpha] = (L[sup n] + k)M/(L[sup n]M + k), [beta] = (1 [minus] [alpha]V[sub f])/(1 [minus] V[sub f]), where the constants n and k are obtained experimentally. When k = 0.0222 and n = 0.45, E[sub c] of the TPE composites agreed well with the prediction of the proposed model. The relaxation spectrum of the composites showed a distinct main peak ascribed to the matrix elastomer, but no peak to the PET fiber.

Guo, Wuyun; Ashida, Michio (Kobe Univ., (Japan). Graduate School of Science and Technology)

1993-11-20

322

Sensitivity analysis for the process integrated online polarization of piezoceramic modules in thermoplastic composites  

NASA Astrophysics Data System (ADS)

The use of active composite structures in high-volume applications requires novel robust manufacturing processes as well as specially adapted functional modules. The paper presents actual research results with regard to the process-immanent polarization of novel thermoplastic-compatible piezoceramic modules (TPM) during the consolidation process of active fibre-reinforced thermoplastic composite structures. In particular the influence of varying manufacture process parameters of a hot-press process on the polarization behaviour is investigated. The main principal objective is the purposeful utilization of process parameters for polarization support.

Hufenbach, W.; Gude, M.; Modler, N.; Heber, T.; Tyczynski, T.

2010-10-01

323

The reclaiming of butyl rubber and in-situ compatibilization of thermoplastic elastomer by power ultrasound  

NASA Astrophysics Data System (ADS)

This is a study of the continuous ultrasound aided extrusion process for the in-situ compatibilization of isotactic polypropylene (iPP)/ethylene-propylene diene rubber (EPDM) thermoplastic elastomer (TPE) using a newly developed ultrasonic treatment reactor. The rheological, mechanical properties and morphology of the TPE with and without ultrasonic treatment were studied. In-situ compatibilization in the ultrasonically treated blends was observed as evident by their more stable morphology after annealing, improved mechanical properties and IR spectra. The obtained results indicated that ultrasonic treatment induced the thermo-mechanical degradations and led to the possibility of enhanced molecular transport and chemical reactions at the interfaces. Processing conditions were established for enhanced in situ compatibilization of the PP/EPDM TPE. The ultrasonic treatments of butyl rubber gum and ultrasonic devulcanization of butyl rubber, tire-curing bladder during extrusion using a grooved barrel ultrasonic reactor were carried out. The ultrasonic treatment of gum caused degradation of the polymer main chain leading to lower molecular weight, broader molecular weight distribution, less unsaturation and changes in physical properties. The devulcanization of butyl rubber was successfully accomplished only at severe conditions of ultrasonic treatment. The mechanical properties of vulcanizates prepared from devulcanized butyl rubber are comparable to that of the virgin vulcanizate. The molecular characterization of sol fraction of devulcanized butyl rubber showed the devulcanization and degradation of butyl rubber occurred simultaneously. 1H NMR transverse relaxation was also used to study butyl rubber gum before and after ultrasonic treatment, and ultrasonically devulcanized unfilled butyl rubber. The T2 relaxation decays were successfully described using a two-component model. The recyclability of tire-curing bladder was also investigated. Gel fraction, crosslink density, cure behavior, dynamic properties and mechanical properties were measured. Good mechanical properties of revulcanized rubber were achieved by blending devulcanized rubber with the carbon black filled virgin butyl rubber. The structural characteristics of devulcanized butyl rubber were simulated using the Dobson-Gordon theory of rubber network statistics. A fairly good agreement between experimental data and theoretical prediction on normalized gel fraction vs. normalized crosslink density was achieved. The simulation of devulcanized butyl rubber indicated that the rate of crosslink rupture is much higher than that of the main chain.

Feng, Wenlai

324

Through-transmission ultrasonics for on-line sensing and control of thermoplastic fusion bonding processes  

NASA Astrophysics Data System (ADS)

The focus of this work is to develop Through-Transmission Ultrasonics (TTU) as a process monitoring technique for non-intrusive, on-line control of thermoplastic fusion bonding. A model is developed to predict the TTU amplitude of a fusion bond by joining the theory of ultrasonic wave propagation through multilayered structures with a model for the evolution of intimate contact at the material interfaces. A new approach, the Averaged Transmission Model (ATM), is developed for treating the effects of imperfect contact at the bond interface. This approach is based upon statistical averaging of the transmission coefficients for the various sound paths between source and receiver. The extension of the model for an arbitrary number of rough interfaces is derived. The temperature dependence of sound velocity and ultrasonic attenuation of the materials are important properties. Experimental techniques based on both pulse-echo and laser ultrasonics in through-transmission mode were developed to characterize these properties at temperatures approaching 330°C. Validation of the ATM was accomplished by comparison of model predictions for PEEK polymer and PEEK/AS4 composites to data from resistance welding experiments. These studies were conducted in three phases. Phase one explored the TTU response to temperature at a fixed degree of intimate contact. Model results correlated well to experimental measurements. In phase two, interface structure was controlled to determine the effect of variable contact on the TTU amplitude at a fixed temperature. Model predictions were compared to TTU measurements for both single and dual interface cases with favorable results. In the phase three, model predictions were compared to results of a post-process TTU inspection of isothermally processed resistance welds. Model results were in agreement with experimental over a wide range of processing times. Hertzian contact theory was used to modify the initial degree of contact resulting from consolidation pressure. Strength development in the third-phase welds was determined to be intimate contact controlled, establishing a direct relationship between TTU amplitudes and strength. A near-linear relationship was found, demonstrating the potential for on-line, non-intrusive monitoring of weld strength.

Tackitt, Kirk David

325

Synthesis and characterization of PMMA\\/PEG-TPE semi-interpenetrating polymer networks  

Microsoft Academic Search

Two-component semi-interpenetrating polymer networks (Semi-IPNs) of thermoplastic urethane elastomer based on poly(ethylene\\u000a glycol) and polymethyl methyacrylate were synthesized by the sequential technique. The Semi-IPNs obtained were characterized\\u000a with respect to their mechanical properties such as tensile strength, elongation. Glass transition temperatures were carried\\u000a out using dynamic mechanical thermal analysis. Phase morphology was studied by scanning electron microscopy. The effect of

Xiao-xia Jian; Le-qin Xiao; Wei-liang Zhou; Fu-ming Xu

2009-01-01

326

Novel routes to liquid-based self-healing polymer systems  

Microsoft Academic Search

Inspired by the current state-of-the-art and the progressing advancements in the field of self-healing materials, this thesis addresses several novel routes to advance the concept of liquid-based self-healing polymer systems.\\u000aThis thesis presents the concept and characterisation of a one-component solvent-based healing mechanism for thermoplastic materials and in addition to the healing strategy, a new capsular architecture is proposed for

S. D. Mookhoek

2010-01-01

327

Adhesive strength of bonds of polymers with carbon fibres at different loading rates  

Microsoft Academic Search

The effect of the loading rate on the strength of the interface of bonds of UKN-5000-P carbon fibres ?7 ?m in diameter with\\u000a thermosetting (EDT-10 epoxy binder) and thermoplastic (PSK-1 polyarylene sulfone) matrices was investigated. The adhesive\\u000a strength ?0 of the bonds was determined in shear of a monofilament relative to the polymer layer (pull-out method). It was found that

Yu. A. Gorbatkina; V. G. Ivanova-Mumzhieva; A. Ya. Gorenberg

1999-01-01

328

Environmentally degradable, high-performance thermoplastics from phenolic phytomonomers  

Microsoft Academic Search

Aliphatic polyesters, such as poly(lactic acid), which degrade by hydrolysis, from naturally occurring molecules form the main components of biodegradable plastics. However, these polyesters have become substitutes for only a small percentage of the currently used plastic materials because of their poor thermal and mechanical properties. Polymers that degrade into natural molecules and have a performance closer to that of

Tatsuo Kaneko; Tran Hang Thi; Dong Jian Shi; Mitsuru Akashi

2006-01-01

329

Weathering resistance of halogen-free flame retardance in thermoplastics  

Microsoft Academic Search

The influence of weathering on the fire retardancy of polymers is investigated by means of a cone calorimeter test, before and after artificial weathering. The surface degradation was monitored using different techniques (ATR–FTIR, microscopy, colour measurement). Different kinds of polymeric materials were chosen, all as they are used in practice: polycarbonate (PC) blends, polyamide (PA) and polypropylene (PP) flame-retarded with

U. Braun; V. Wachtendorf; A. Geburtig; H. Bahr; B. Schartel

2010-01-01

330

Development of thermoplastic composite tubes for large deformation  

NASA Astrophysics Data System (ADS)

Composites have proved their great potentials for many aerospace applications, where the high performance can justify the high cost. However, the brittleness of the composites has been a main drawback for many applications that require large deformation, high failure strain and extensive energy absorption before final fracture. The objective of this research is to present a solution to the brittleness of the composites in tubular form and to introduce a composite tube that shows the same strength, stiffness and failure strain as its high grade Aluminum 7075-T6 counterpart tube. One application of this research can be in the development of composite landing gear for helicopters. Up to date, almost all helicopter landing gears are made of high strength aluminum, and despite their major issues in maintenance and fabrication, aluminum landing gears have remained the only choice for the helicopter manufacturing industry. Substitution of aluminum landing gear for helicopters with a thermoplastic composite landing gear is really a challenge, but if this can be done, it would be for the first time in the world! Through this research, the mechanical behavior of flat plate Carbon AS4/PEKK is characterized, and the potential mechanisms for large deformation of composite laminates are sought. The outcomes are used to design a composite tube that shows the same strength, stiffness and deformability as its high grade aluminum counterpart. The accuracy of the design is verified through progressive failure by ANSYS analysis and experimental work. Strain Controlled Design is introduced as a new design technique to substitute for the traditional stiffness-controlled techniques whenever large deformation from composite laminates is expected. The analytical techniques for stress analysis of composite tubes are reviewed, and the cumbersomeness of the method is highlighted. Finally, a simplified technique is presented to analyze composite tubes as a sandwich panel model. The results of the analysis are compared with the ANSYS and experimental results. Agreement between three methods is demonstrated. Moreover, guidelines for the design of composite tubes that exhibit large deformation before failure are presented.

Derisi, Bijan

331

Investigation on the mechanism of aminosilane-mediated bonding of thermoplastics and poly(dimethylsiloxane).  

PubMed

A possible mechanism for the aminosilane-mediated room-temperature (RT) bonding of thermoplastics and poly(dimethylsiloxane) (PDMS) is presented. The plasma-activated thermoplastic or PDMS substrates were modified with alkoxy silanes having different organo functional groups, and their bonding characteristics were studied. Manual peeling tests revealed that strong bonding was realized only when the silane had a free amino group and at least two alkoxy groups on the silicon. Silanization was carried out in both aqueous and anhydrous conditions; bonding occurred readily at RT in the former case, but a longer incubation time or a higher temperature was needed for the latter. The presence of the silane on the surface was confirmed by contact-angle measurements and UV spectrophotometric, attenuated total reflectance infrared spectroscopic (ATR-IR) and X-ray photoelectron spectroscopic (XPS) analyses. In the case where the aminosilane was deposited from aqueous solution, the amino functionality of the silane-catalyzed siloxane bond formation between the silanol on the modified thermoplastic surface and the silanol of the plasma-activated PDMS. In the case of anhydrous phase deposition, the aminosilane first catalyzed the hydrolysis of the ethoxy groups on the silicon, and then, catalyzed the condensation between the silanol groups of both materials. Shelf life tests of the modified thermoplastics showed that the aminosilane was stable over 2 weeks, and that bonding occurred at RT when the substrates were soaked in water before bonding. PMID:23198791

Sunkara, Vijaya; Cho, Yoon-Kyoung

2012-12-12

332

Effect of insert temperature on integrity of a thermoplastic circuit board  

Microsoft Academic Search

At Loughborough University an environmentally friendly manufacturing process for electronic circuits, involving the embedding of electronic components in thermoplastic resins via insert injection moulding, is under development. Once embedded, interconnection between components is achieved by subsequently plating or printing metallisation patterns on the moulding surface. The environmental benefits of the process arise from the enhanced separability of components, metals and

Hrushikesh Abhyankar; D. Patrick Webb; David A. Hutt

2010-01-01

333

The thermoplastic Minerva body jacket: a clinical comparison with other cervical spine splinting techniques.  

PubMed

A retrospective analysis of the efficacy of a variety of external stabilization techniques used in 155 cases of unstable cervical spine injuries is presented. The movement at each intervertebral level was evaluated during thermoplastic Minerva body jacket stabilization in 18 additional patients. Many currently available approaches to external stabilization of the cervical spine were, thus, assessed. Thermoplastic Minerva body jacket stabilization offered superior segmental immobilization compared with published data for the halo. It is concluded that some unstable injuries to the high cervical spine might best be treated with a halo device, whereas mid to low cervical injuries and the remaining upper cervical spine injuries appear to be optimally treated with a Minerva jacket. Lesser injuries may be treated with a variety of available orthoses. The thermoplastic Minerva body jacket offers a superior limitation of intervertebral movement compared with other commonly used braces, including the halo jacket, for most cervical spine injuries. The technique of application of the thermoplastic Minerva body jacket is reviewed. PMID:1520990

Benzel, E C; Larson, S J; Kerk, J J; Millington, P J; Novak, S M; Falkner, R H; Wenninger, W J

1992-09-01

334

Treatment of thermoplastic rubberwith chlorine bleach as an alternative halogenation treatment in the footwear industry  

Microsoft Academic Search

Avoidance of solvents in bonding operations is a current demand in the footwear industry. Halogenation of rubber soles with solutions of trichloroisocyanuric acid (TCI) in different solvents has been successfully used to improve bonding to the leather uppers. In this study, the use of chlorine bleach as an alternative water surface treatment for a rubber has been tested. A thermoplastic

C. M. Cepeda-Jiménez; M. M. Pastor-Blas; J. M. Martín-Martínez; P. Gottschalk

2003-01-01

335

Influence of Molecular Weight on the Mechanical Performance of a Thermoplastic Glassy Polyimide  

Microsoft Academic Search

Mechanical testing of an advanced thermoplastic polyimide (LaRC™-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The physical characterization, elastic properties and notched tensile strength were all determined as a function of molecular weight and test temperature. It was shown that notched tensile strength is a strong function of both

Lee M. Nicholson; Karen S. Whitley; Thomas S. Gates; Jeffrey A. Hinkley

1999-01-01

336

Influence of molecular weight on the mechanical performance of a thermoplastic glassy polyimide  

Microsoft Academic Search

Mechanical testing of an advanced thermoplastic polyimide (LaRCTM-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The physical characterization, elastic properties and notched tensile strength were all determined as a function of molecular weight and test temperature. It was shown that notched tensile strength is a strong function of both

L. M. Nicholson; K. S. Whitley; T. S. Gates; J. A. Hinkley

2000-01-01

337

Innovative thermoplastic pole design sets new reliability and environmental standards for vacuum breaker technology  

Microsoft Academic Search

ABB has over 10 years of experience in the use of embedded pole technology based on epoxy insulation in medium-voltage circuit breakers with vacuum interrupters. The next significant step in this technology is the development of embedded poles that use a thermoplastic material.

D. Gentsch; A. Klaska; Zhanwei Tu; YuRong Lv

2011-01-01

338

Development of LaRC (TM): Ia Thermoplastic Polyimide Coated Aerospace Wiring.  

National Technical Information Service (NTIS)

NASA Langley has invented LaRC(exp TM) IA and IAX which are thermoplastic polyimides with good melting, thermal and chemical resistance properties. It was the objective of this contract to prepare and extrude LaRC (exp TM) polyimide onto aircraft wire and...

J. Keating

1995-01-01

339

Study of thermal and fire behavior of wood fiber\\/thermoplastic composite materials  

Microsoft Academic Search

The fire safety characteristics of wood fiber\\/thermoplastic composite materials were investigated in this study. Composites comprising wood fiber fillers and polymeric binders are known to offer many advantages such as good strength to weight ratio, ease of manufacture, low cost, and the possibility for recycling. In spite of these advantages however, the fire safety question of plastic-based materials is an

Adedejo Bukola Oladipo

1998-01-01

340

Modeling of Heat Transfer and Void Dynamics for the Thermoplastic Composite Tow-placement Process  

Microsoft Academic Search

Thermoplastic composite tow-placement technology is a nonautoclave consolidation process that offers the potential to significantly reduce fabrication costs by using in situ consolidation as a method for manufacturing large composite components. The temperature history and resulting degree of consolidation directly control the final part quality and are directly affected by the process set points. In this work, series of integrated

John Tierney; John W. Gillespie

2003-01-01

341

Analysis of transport phenomena governing interfacial bonding and void dynamics during thermoplastic tow-placement  

Microsoft Academic Search

The thermoplastic automated tow-placement process offers the potential for cost-effective fabrication of composite parts via consolidation in situ, thus avoiding the costly autoclave consolidation. The degree of interfacial bonding between tow layers and the void content in the composite laminate directly affect the mechanical properties and performance of the products. Theoretical models for the physical phenomena governing interfacial bonding and

M. A. Lamontia; S. Ranganathan; R. C. Don; J. W. Gillespie Jr.

1996-01-01

342

Processing, performance and biodegradability of a thermoplastic aliphatic polyester\\/starch system  

Microsoft Academic Search

Composites of a biodegradable thermoplastic aliphatic polyester, polybutylene succinate adipate (PBSA), with granular corn starch were investigated for processability, mechanical and thermal properties, and biodegradability. The PBSA\\/starch films were prepared with starch contents of 5%–30% by weight and processed by blown film extrusion. Increasing the starch content led to an increase in modulus and decreases in tensile strength, elongation to

Jo Ann Ratto; Peter J. Stenhouse; Margaret Auerbach; John Mitchell; Richard Farrell

1999-01-01

343

Adhesion between individual components and mechanical properties of natural rubber-polypropylene thermoplastic elastomeric blends  

Microsoft Academic Search

Adhesion between individual components and the mechanical properties of natural rubber (NR)-polypropylene (PP) thermoplastic elastomeric blends with reference to adhesion have been studied. The adhesion strength between the component phases was varied by incorporating a third component, namely ethylene propylene diene rubber (EPDM) or chlorinated polyethylene (CPE), and their effects on the mechanical properties were also studied. It was observed

Namita Roy Choudhury; Anil K. Bhowmick

1988-01-01

344

Studies on a Novel Thermoplastic Polyurethane as a Binder for Extruded Composite Propellants  

Microsoft Academic Search

Extruded composite propellant (ECP) is an entirely new thrust area in the development of composite propellants within India. These are based on high-density thermoplastic elastomers as a propellant binder with ammonium perchlorate (AP) as an oxidizer and aluminum (Al) as a metallic fuel. Thus, this class of propellant not only provides higher energy but also yields higher density impulse. There

K. S. Mulage; R. N. Patkar; V. D. Deuskar; S. M. Pundlik; S. D. Kakade; M. Gupta

2007-01-01

345

Improved fracture toughness of carbon fibre\\/epoxy composite laminates using dissolvable thermoplastic fibres  

Microsoft Academic Search

This paper reports on a novel toughening concept based on dissolvable phenoxy fibres, which are added at the interlaminar region in a carbon fibre\\/epoxy composite. The composites were prepared by resin infusion of carbon fibre fabric with the phenoxy introduced as a chopped fibre interleaf between the carbon fibre plies. The thermoplastic phenoxy fibre dissolved in the epoxy during curing

Doris W. Y. Wong; Lin Lin; P. Terry McGrail; Ton Peijs; Paul J. Hogg

2010-01-01

346

Thermoplastic elastomers based on polypropylene\\/natural rubber and polypropylene\\/recycle rubber blends  

Microsoft Academic Search

Fine rubber powder obtained from the sanding process of polishing rubber balls and artificial eggs (recycled rubber, RR) was used to prepare polypropylene (PP)\\/RR blends, a thermoplastic elastomer using different RR content. A similar series of blends using natural rubber, SMR L (NR) was also prepared. The results indicated that at a similar rubber content, PP\\/RR blends have higher, tensile

H Ismail; Suryadiansyah

2002-01-01

347

Analysis of the formation and removal of gas bubbles in rotationally moulded thermoplastics  

Microsoft Academic Search

The presence of internal bubbles is a characteristic feature of thermoplastic products manufactured by rotational moulding. The bubbles in the mouldings are generally undesirable since they reduce strength and stiffness and impair the appearance of the product if they occur at the surface. The bubbles form as a result of powder particles coalescing during the heating stage of the process

L. Xu; R. J. Crawford

1993-01-01

348

SOLVENTLESS MANUFACTURE OF ARTILLERY PROPELLANT USING THERMOPLASTIC ELASTOMER BINDER, PP-867  

EPA Science Inventory

Multi-base gun propellant for artillery ammunition creates 0.3 lb of solvent emissions per lb of propellant, and at expected production rates of 3 million lb/yr, this represents the largest source of VOC emissions due to gun propellant production. New thermoplastic elastomer (TP...

349

Hybrid recycled glass fiber\\/wood flour thermoplastic composites: Manufacturing and mechanical characterization  

Microsoft Academic Search

Hybrid thermoplastic composites from wood flour and recycled glass fibers were manufactured through a two-step process involving a kinetic mixer and a compression molding machine. To evaluate the effect of recycled glass fibers, hybrid composites containing virgin glass fibers were also manufactured and tested. Mechanical properties of the composites including flexural modulus and strength, hardness as a function of temperature,

Marco Valente; Fabrizio Sarasini; Francesco Marra; Jacopo Tirillò; Giovanni Pulci

2011-01-01

350

Production of natural fiber reinforced thermoplastic composites through the use of polyhydroxybutyrate-rich biomass  

Microsoft Academic Search

Previous research has demonstrated that production of natural fiber reinforced thermoplastic composites (NFRTCs) utilizing bacterially-derived pure polyhydroxybutyrate (PHB) does not yield a product that is cost competitive with synthetic plastic-based NFRTCs. Moreover, the commercial production of pure PHB is not without environmental impacts. To address these issues, we integrated unpurified PHB in NFRTC construction, thereby eliminating a significant energy and

Erik R. Coats; Frank J. Loge; Michael P. Wolcott; Karl Englund; Armando G. McDonald

2008-01-01

351

Weld strength of laser-assisted tape-placed thermoplastic composites  

Microsoft Academic Search

Laser-assisted tape placement is an attractive manufacturing technology for the aerospace industry as it combines high productivity with low energy consumption. It comprises the automated deposition of fiber reinforced thermoplastic tapes to incrementally build up a structure. The process can also be used to tailor the properties of conventionally manufactured woven fabric reinforced components by locally reinforcing these with unidirectionally

W. J. B. Grouve

2012-01-01

352

Microcellular foams of thermoplastic vulcanizates (TPVs) based on waste ground rubber tire powder  

Microsoft Academic Search

With the increased adoption of thermoplastic vulcanizates (TPVs) in automotive weather seal systems, the foams of TPVs present an important milestone in providing key applications such as trunk and door seals. In this study, microcellular foams of TPV based on waste ground rubber tire powder (WGRT) were investigated. In order to investigate the relationship between processing conditions and structure of

Zhen Xiu Zhang; Shu Ling Zhang; Sung Hyo Lee; Dong Jin Kang; Jin Kuk Kim

2008-01-01

353

Recycling of ligno-cellulosic and polyethylene wastes from agricultural operations in thermoplastic composites  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the US, wood plastic composites (WPC) represent one of the successful markets for natural fiber-filled thermoplastic composites. In the past several years, the availability of good quality wood fiber has been diminishing and prices of wood and plastic have been increasing. Therefore, the vast qua...

354

Recycling of Ligno-Cellulosic and Polythylene Wastes from Agriculture Operations in Thermoplastic Composites  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the US, wood plastic composites (WPC) represent one of the successful markets for natural fiber-filled thermoplastic composites. In the past several years, the availability of good quality wood fiber has been diminishing and prices of wood and plastic have been increasing. Therefore, the vast qua...

355

Weight loss during different weathering tests of industrial thermoplastic elastomer polyurethane-coated fabrics  

Microsoft Academic Search

Measurement of weight loss may be used to follow weathering of industrial thermoplastic elastomer polyurethane (TPU)-coated fabrics. We compared artificial weathering of three TPU-coated fabrics in a Weatherometer test with and without water spray with natural weathering carried out in Florida. The loss of weight with time was found to be a sensitive measure of the degradation due to weathering.

Stéphanie Hollande; Jean-Louis Laurent

1998-01-01

356

Effect of carbonyl content on the properties of thermoplastic oxidized starch  

Microsoft Academic Search

In order to improve the properties of starch, oxidized starches (OS) with different carbonyl contents were prepared by hydroxyl peroxide under mild conditions. Glycerol as a plasticizer was added into OS to produce thermoplastic oxidized starches (TPOS). It was found that the content of carbonyl and carboxyl had a great effect on the thermal properties, mechanical properties and moisture resistance

Yu-Rong Zhang; Shui-Dong Zhang; Xiu-Li Wang; Rong-Yi Chen; Yu-Zhong Wang

2009-01-01

357

Optimization of Laser Transmission Welding Process for Thermoplastic Composite Parts using ThermoMechanical Simulation  

Microsoft Academic Search

An innovative methodology for the thermo-mechanical simulation of the laser transmission welding (LTW) process for thermoplastic components is presented. The work consists of two parts. In the first part, a finite element (FE) thermal model is developed, for the prediction of the transient spatial temperature history developing during the LTW process. Experimental measurements have been used for the calibration of

G. N. Labeas; G. A. Moraitis; Ch V. Katsiropoulos

2010-01-01

358

Influence of thermal stresses in modelling the lap welding of thermoplastic films  

Microsoft Academic Search

Our study has shown that the influence of the thermal stresses and expansion and contraction forces acting during and after laser action plays an ultimate role on the achievement of strong welds, that is, weld with tensile strength higher than 80% of that of the original thermoplastic. This has direct influence on engineering parameters, making necessary to have a minimum

J. M. P. Coelho; M. A. Abreu; F. C. Rodrigues

2005-01-01

359

LASER BEAM WELDING OF THERMOPLASTICS PARAMETER INFLUENCE ON WELD SEAM QUALITY - EXPERIMENTS AND MODELING  

Microsoft Academic Search

Laser beam welding of thermoplastics offers process technical advantages due to contact-less energy input, which is spatially (?100 µm) and timely (? ms) very well defined. Different process strategies are possible leading to flexibility, product adapted irradiation, short process times and high quality seams, while avoiding mechanical stress and thermal load on the joining partners. Meanwhile, laser beam welding of

Ulrich-Andreas Russek; Mirko Aden; Jens Poehler; Andre Palmen; Henrik Staub

360

A phenomenological study of the hot-tool welding of thermoplastics Part 3. Polyetherimide  

Microsoft Academic Search

A hot-tool welding machine was used to study the weldability of polyetherimide, a high-temperature amorphous thermoplastic. Weld strength data are reported for two specimen thicknesses. In these experiments, the outflow in the melting phase was controlled by means of stops, the thickness of the molten film was controlled by the heating time, and the outflow during the final joining phase

Vijay K Stokes

2001-01-01

361

Study of In-Air Thermoplastic Recording of Charactron Charactron CRT Displays.  

National Technical Information Service (NTIS)

In-Air thermoplastic recording of alpha-numeric symbols from a charactron type cathode ray tube is investigated. A technique in electro-photography, the in-air method of recording relies upon a gas discharge of air molecules to form a latent charge patter...

N. F. D'Antonio

1966-01-01

362

Composite structure composed of overlapped fibre bundles, thermoplastic resin and metal plate for secondary forming process  

Microsoft Academic Search

A simple shape of a composite is preferable in mass production, while a curved or stretched shape is sometimes preferable for final products. High formability would enable the composite to deform into a preferable shape by secondary forming. In this paper, a structure for a composite is proposed to enhance formability. The composite is composed of reinforcing fibre bundles, thermoplastic

Takashi Kuboki; Shun-ichi Uematsu; Makoto Murata

2010-01-01

363

A Physically Based Failure Hypothesis for Short-Fibre Reinforced Thermoplastics for Finite-Element-Analysis  

Microsoft Academic Search

A physically based failure hypothesis is developed for short fibre reinforced thermoplastics. The mode l is valid for three-dimensional, multiaxial stress stat es. We begin the approach by reviewing uniaxial tensile strength models, which take the fibre orientation and fibre length distribution into account and use the critical fibre length concept to distinguish betwee n fibre- pullout and fibre breakage

B. Mlekusch; B. Spiegl; A. Ableidinger

364

A numerical and experimental investigation to the optimization of the thermoplastic reinforced sheet deep drawing  

Microsoft Academic Search

b TAM of Iran Khodro Company (IKCO) Abstract: Process design in thermoplastic reinforced sheet deep drawing involves many areas, such as determination of die design, selection of process parameters and initial blank shape design. Initial blank design in the composite sheet deep drawing refers to the design of blank initial geometry and it can help the produced part to be

A. Agahi; M. Shirani; S. A. Sadough; A. Alikhani

365

Development of neutron shielding material using metathesis-polymer matrix  

NASA Astrophysics Data System (ADS)

A neutron shielding material using a metathesis-polymer matrix, which is a thermosetting resin, was developed. This shielding material has characteristics that can be controlled for different mixing ratios of neutron absorbers and for formation in the laboratory. Additionally, the elastic modulus can be changed at the hardening process, from a flexible elastoma to a mechanically tough solid. Experiments were performed at the Kyoto University Research Reactor in order to determine the important characteristics of this metathesis-polymer shielding material, such as neutron shielding performance, secondary gamma-ray generation and activation. The metathesis-polymer shielding material was shown to be practical and as effective as the other available shielding materials, which mainly consist of thermoplastic resin.

Sakurai, Yoshinori; Sasaki, Akira; Kobayashi, Tooru

2004-04-01

366

Silicon Polymers.  

National Technical Information Service (NTIS)

Unsaturated carbosilane polymers have been prepared by anionic as well as metathesis polymerization of silacyclopent-3-enes. Of particular interest, is unsaturated carbosilane polymers with Si-H substitution have been prepared. These complementary functio...

W. P. Weber

1992-01-01

367

Piezoelectric Polymers.  

National Technical Information Service (NTIS)

The purpose of this review is to detail the current theoretical understanding of the origin of piezoelectric and ferroelectric phenomena in polymers; to present the state-of-the-art in piezoelectric polymers and emerging material systems that exhibit prom...

J. S. Harrison Z. Ounaies

2001-01-01

368

Thermal energy storage material comprising hydrated compound and water-swollen cross-linked polymer  

SciTech Connect

The thermal energy storage material comprises at least one hydrated compound (Such as an inorganic salt) having a reversible transition to the anhydrous or a less hydrated form and a hydrogel, comprising a water-swollen cross-linked polymer formed by cross-linking a synthetic hydrophilic polymer by a covalent cross-linking mechanism, throughout which the compound is dispersed. The hydrogel is made by reacting a water-soluble or water-dispersible synthetic hydrophilic polymer, which is preferably linear and thermoplastic, with a cross-linking agent therefor in an aqueous medium containing the hydrated compound. The hydrophilic polymer, the aqueous medium and the hydrated compound are used in such amounts that the storage material contains a major proportion, by weight, of the hydrated compound and a minor proportion, by weight, of the cross-linked polymer.

Kent, P.J.; Page, J.K.

1981-06-16

369

High-precision flexible fabrication of tissue engineering scaffolds using distinct polymers.  

PubMed

Three-dimensional porous structures using biodegradable materials with excellent biocompatibility are critically important for tissue engineering applications. We present a multi-nozzle-based versatile deposition approach to flexibly construct porous tissue engineering scaffolds using distinct polymeric biomaterials such as thermoplastic and photo-crosslinkable polymers. We first describe the development of the deposition system and fabrication of scaffolds from two types of biodegradable polymers using this system. The thermoplastic sample is semi-crystalline poly(?-caprolactone) (PCL) that can be processed at a temperature higher than its melting point and solidifies at room temperature. The photo-crosslinkable one is polypropylene fumarate (PPF) that has to be dissolved in a reactive solvent as a resin for being cured into solid structures. Besides the direct fabrication of thermoplastic PCL scaffolds, we specifically develop a layer molding approach for the fabrication of crosslinkable polymers, which traditionally can only be fabricated by stereolithography. In this approach, a thermoplastic supporting material (paraffin wax) is first deposited to make a mold for each specific layer, and then PPF is deposited on demand to fill the mold and cured by the UV light. The supporting material can be removed to produce a porous scaffold of crosslinked PPF. Both PCL and crosslinked PPF scaffolds fabricated using the developed system have been characterized in terms of compressive mechanical properties, morphology, pore size and porosity. Mouse MC3T3-E1 pre-osteoblastic cell studies on the fabricated scaffolds have been performed to demonstrate their capability of supporting cell proliferation and ingrowth, aiming for bone tissue engineering applications. PMID:22635324

Wei, Chuang; Cai, Lei; Sonawane, Bhushan; Wang, Shanfeng; Dong, Jingyan

2012-05-25

370

Hazardous Air Pollutant Emissions from Process Units in the Thermoplastics Manufacturing Industry. Basis and Purpose Document for Proposed Standards.  

National Technical Information Service (NTIS)

The document provides the background information and rationale for the decisions made in the (proposed) standards setting process for the thermoplastics manufacturing industry. The affected industry is described, the baseline organic HAP emissions are pre...

1995-01-01

371

Role of Molecular Weight and Temperature on the Elastic and Viscoelastic Properties of a Glassy Thermoplastic Polyimide.  

National Technical Information Service (NTIS)

Mechanical testing of the elastic and viscoelastic response of an advanced thermoplastic polyimide (LaRC-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The notched tensile s...

L. M. Nicholson K. S. Whitley T. S. Gates

2001-01-01

372

Lead-Based Paint Hazard Abatement System Utilizing a Carrier-Based Fusible Thermoplastic Resinous Coating. Product Development Manual.  

National Technical Information Service (NTIS)

This product development manual describes the materials specifications, cost estimate, and preparation of thermoplastic composition for YRL 100, a lead - based paint hazard abatement system, developed by Yarsley Research Laboratories (YRL) Limited. The co...

W. Flavell A. P. Verrall

1979-01-01

373

Procedures to reduce reflection on polymer surfaces  

NASA Astrophysics Data System (ADS)

Antireflection (AR) properties are required for optical surfaces to avoid disturbing reflections as well as to improve the transmission of optical systems. The common method to reduce the reflection on optics is vacuum deposition of interference coatings. However, special efforts are required for each type of plastic to develop polymer-capable vacuum coating processes due to the manifold chemical and physical properties of optical polymers. An alternative procedure for the antireflection of polymers is the generation of surface structures that decrease the index of refraction in a surface region. In this paper, the suitability of the miscellaneous thermoplastic polymers for plasma-ion assisted deposition processes is evaluated. This comprises the study of damage effects caused by the contact with plasma and high-energy radiation as well as the development of special coating designs and of suitable process conditions. Coating properties achieved are discussed for PMMA and poly-cycloolefines. The same ion source arrangement as used for coating has been applied for etching an antireflective sub-wavelength surface structure into PMMA. In summary, the paper shows the practical application fields for both technologies.

Schulz, Ulrike; Munzert, Peter; Kaless, Antje; Lau, Kerstin; Kaiser, Norbert

2005-09-01

374

Functionalized Materials From Elastomers to High Performance Thermoplastics  

SciTech Connect

Synthesis and incorporation of functionalized materials continues to generate significant research interest in academia and in industry. If chosen correctly, a functional group when incorporated into a polymer can deliver enhanced properties, such as adhesion, water solubility, thermal stability, etc. The utility of these new materials has been demonstrated in drug-delivery systems, coatings, membranes and compatibilizers. Two approaches exist to functionalize a material. The desired moiety can be added to the monomer either before or after polymerization. The polymers used range from low glass transition temperature elastomers to high glass transition temperature, high performance materials. One industrial example of the first approach is the synthesis of Teflon(reg. sign). Poly(tetrafluoroethylene) (PTFE or Teflon(reg. sign)) is synthesized from tetrafluoroethylene, a functionalized monomer. The resulting material has significant property differences from the parent, poly(ethylene). Due to the fluorine in the polymer, PTFE has excellent solvent and heat resistance, a low surface energy and a low coefficient of friction. This allows the material to be used in high temperature applications where the surface needs to be nonabrasive and nonstick. This material has a wide spread use in the cooking industry because it allows for ease of cooking and cleaning as a nonstick coating on cookware. One of the best examples of the second approach, functionalization after polymerization, is the vulcanization process used to make tires. Natural rubber (from the Hevea brasiliensis) has a very low glass transition temperature, is very tacky and would not be useful to make tires without synthetic alteration. Goodyear's invention was the vulcanization of polyisoprene by crosslinking the material with sulfur to create a rubber that was tough enough to withstand the elements of weather and road conditions. Due to the development of polymerization techniques to make cis-polyisoprene, natural rubber is no longer needed for the manufacturing of tires, but vulcanization is still utilized.

Laura Ann Salazar

2003-05-31

375

Large-strain, rigid-to-rigid deformation of bistable electroactive polymers  

NASA Astrophysics Data System (ADS)

Thermoplastic poly(tert-butyl acrylate) (PTBA) is reported as an electroactive polymer that is rigid at ambient conditions and turns into a dielectric elastomer above a transition temperature. In the rubbery state, a PTBA thin film can be electrically actuated to strains up to 335% in area expansion. The calculated actuation pressure is 3.2 MPa. The actuation is made bistable by cooling to below glass transition temperature. The PTBA represents the bistable electroactive polymer (BSEP) that can be actuated to various largely strained, rigid shapes. The application of the BSEP for refreshable Braille display, an active tactile display, is also demonstrated.

Yu, Zhibin; Yuan, Wei; Brochu, Paul; Chen, Bin; Liu, Zhitian; Pei, Qibing

2009-11-01

376

Low temperature cure of unsaturated polyester resins with thermoplastic additives. II. Structure formation and shrinkage control mechanism  

Microsoft Academic Search

An important feature in the cure of unsaturated polyester (UP)\\/styrene\\/thermoplastics system is the formation of a two-phase structure. Its final morphology is primarily determined by the phase separation process and the gelation resulting from the polymerization. In this study, the phase separation process during the cure of UP resins with thermoplastic additives was investigated by optical microscopy. It was found

W Li; L. J Lee

2000-01-01

377

Durability-Based Design Criteria for a Quasi-Isotropic Carbon-Fiber-Reinforced Thermoplastic Automotive Composite  

Microsoft Academic Search

This report provides recommended durability-based design properties and criteria for a quais-isotropic carbon-fiber thermoplastic composite for possible automotive structural applications. The composite consisted of a PolyPhenylene Sulfide (PPS) thermoplastic matrix (Fortron's PPS - Ticona 0214B1 powder) reinforced with 16 plies of carbon-fiber unidirectional tape, [0?\\/90?\\/+45?\\/-45?]2S. The carbon fiber was Hexcel AS-4C and was present in a fiber volume of 53%

Dan J Naus; James Corum; Lynn B Klett; Mike Davenport; Rick Battiste; Simpson Jr. William A

2006-01-01

378

Conjugated polymers: Watching polymers dance  

NASA Astrophysics Data System (ADS)

Single-molecule spectroscopy allows fluctuations of conjugated polymer conformation to be monitored during solvent vapour annealing. Dramatic changes in fluorescence behaviour are observed and interpreted in terms of transformations between extended and collapsed polymer geometries.

Rothberg, Lewis

2011-06-01

379

Selective separation of virgin and post-consumer polymers (PET and PVC) by flotation method  

SciTech Connect

More and more polymer wastes are generated by industry and householders today. Recycling is an important process to reduce the amount of waste resulting from human activities. Currently, recycling technologies use relatively homogeneous polymers because hand-sorting waste is costly. Many promising technologies are being investigated for separating mixed thermoplastics, but they are still uneconomical and unreliable. At present, most waste polymers cause serious environmental problems. Burning polymers for recycling is not practiced since poisonous gases are released during the burning process. Particularly, polyvinyl chloride (PVC) materials among waste polymers generate hazardous HCl gas, dioxins containing Cl, etc., which lead to air pollution and shorten the life of the incinerator. In addition, they make other polymers difficult to recycle. Both polyethylene terephthalate (PET) and PVC have densities of 1.30-1.35 g/cm{sup 3} and cannot be separated using conventional gravity separation techniques. For this reason, polymer recycling needs new techniques. Among these techniques, froth flotation, which is also used in mineral processing, can be useful because of its low cost and simplicity. The main objective of this research is to recycle PET and PVC selectively from post-consumer polymer wastes and virgin polymers by using froth flotation. According to the results, all PVC particles were floated with 98.8% efficiency in virgin polymer separation while PET particles were obtained with 99.7% purity and 57.0% efficiency in post-consumer polymer separation.

Burat, Firat; Gueney, Ali [Istanbul Technical University, Faculty of Mines, Mineral Processing Engineering Department, 34469 Maslak, Istanbul (Turkey); Olgac Kangal, M. [Istanbul Technical University, Faculty of Mines, Mineral Processing Engineering Department, 34469 Maslak, Istanbul (Turkey)], E-mail: kangal@itu.edu.tr

2009-06-15

380

The mechanical properties of unidirectional thermoplastic composites manufactured by a micro-braiding technique  

Microsoft Academic Search

‘Micro-braided yarn' has been proposed as a means of overcoming the difficulty of manufacturing long-fiber-reinforced thermoplastic composites. Micro-braided yarn is a processing material system that may be used for complex-shaped composites such as textile structural composites. In this study, unidirectional glass-fiber\\/PA6-Nylon composites manufactured from micro-braided yarns were molded in order to investigate the effect of the micro-braiding structure and processing

M. Sakaguchi; A. Nakai; H. Hamada; N. Takeda

2000-01-01

381

The Preparation of Glycerol Pseudo-Thermoplastic Starch (GTPS) via Gelatinization and Plasticization  

Microsoft Academic Search

To convert starch into glycerol pseudo-thermoplastic starch (GTPS), this research used gelatinization to destroy the crystallinity of starch granules, and then adopted glycerol plasticization to reduce the melting temperature. According to viscosity testing and X-ray diffraction (XRD), starch granules must be completely gelatinized in heated water above 80°C. The gelatinized starch was then plasticized by glycerol. Differential Scanning Calorimetry (DSC)

Chin-An Lin; Chi-Che Tung

2009-01-01

382

Preparation and Stress Relaxation Properties of Thermoplastic Polysiloxane-Block-Polyimides  

Microsoft Academic Search

Three series of thermoplastic polysiloxane-block-polyimides were prepared from 3, 3?, 4, 4?-benzophenonetetracarboxylic dianhydride, aromatic diamines with four phenylene rings and diamine-terminated polydimethylsiloxane (Mw D 1240). The tensile modulus of their films was lowered and the coefficient of thermal expansion was increased with increasing polysiloxane composition. The copolyimides showed a good adherence onto silicon wafer even without adhesion promoter added. The

Nobuyuki Furukawa; Yasuharu Yamada; Yoshiharu Kimurak

1996-01-01

383

Migration of Processing Oils of Thermoplastic Rubber Treated with RF Plasma  

Microsoft Academic Search

The surface modifications produced by a RF plasma treatment on a thermoplastic styrene–butadiene–styrene rubber–SBS—with a\\u000a considerable amount of processing oils in its formulation (TRO) have been studied and compared to the modifications produced\\u000a on an oil-free SBS rubber (TRF). The modifications produced by the plasmas on the rubber surface depended on the nature of\\u000a the gas used to generate the

Ana B. Ortíz-Magán; M. Mercedes Pastor-Blas

2008-01-01

384

Copper injection molding using a thermoplastic binder based on paraffin wax  

Microsoft Academic Search

In this work the processing steps for producing copper parts by means of metal injection molding technique were investigated. Different feedstocks were prepared from gas atomized copper powder and a thermoplastic binder based on paraffin wax. The optimum formulation of 95\\/5 wt\\/wt (copper powder\\/binder) was selected from rheological investigation and then the suitable feedstock was injected successfully at low pressure.

L. Moballegh; J. Morshedian; M. Esfandeh

2005-01-01

385

Properties and Preparation of Peroxide Cured PP\\/ Low Crystalline MPE Thermoplastic Vulcanizate  

Microsoft Academic Search

A peroxide cured polypropylene (PP)\\/metallocene polyethylene (mPE) blend to form a thermoplastic vulcanizate has been prepared. The mixing of mPE (40 wt%) and PP (60 wt%) containing a fixed amount of paraffin oil and various dosages of peroxide was performed to prepare the dynamic vulcanized blends using an internal mixer. Crystallinity remained largely unchanged for the PP, indicating the dominant

W.-C. Chen; S.-M. Lai; J.-W. Wang; T.-H. Wu

2008-01-01

386

Dye Penetrant Induced Micro cracking in High Performance Thermoplastic Polyimide Composites  

Microsoft Academic Search

The possibility of spurious microcracking in three high performance thermoplastic polyimide composite materials due to zinc iodine dye penetrant was studied. The material systems were IM7\\/LaRCTM-IAX, IM7\\/LaRCTM-IAX2, and IM7\\/LaRCTM-8515. Specimens from each material system were subjected to one of three immersion tests. The first immersion test involved soaking composite specimens previously prepared with different polishing techniques in dye penetrant. In

A. Paige Clifton Furrow; David A. Dillard; Terry L. St. Clair; Jeffrey Hinkley

1998-01-01

387

N -(2-Hydroxyethyl)formamide as a new plasticizer for thermoplastic starch  

Microsoft Academic Search

N-(2-Hydroxyethyl)formamide (HF) was synthesized efficiently and used as a new plasticizer for corn starch to prepare thermoplastic\\u000a starch (TPS). The hydrogen bond interaction between HF and starch was proved by Fourier-transform infrared (FT-IR) spectroscopy.\\u000a Scanning electron microscope (SEM) revealed that starch granules were completely disrupted and a continuous phase was obtained.\\u000a The crystallinity of corn starch and HF-plasticized TPS (HTPS)

Hongguang Dai; Peter R. Chang; Fei Peng; Jiugao Yu; Xiaofei Ma

2009-01-01

388

Thermoplastic corn starch\\/clay hybrids: Effect of clay type and content on physical properties  

Microsoft Academic Search

Thermoplastic corn starch (TPS) hybrids, plasticized with glycerol and reinforced with two types of clay (sodium montmorillonite and Cloisite® 30B), were prepared by melt-extrusion. Scanning electron microscopy was used to visualize extrudates morphology. The effects of clay content and of glycerol content on the physical properties of extrudates were evaluated. As determined by contact angle measurements and X-ray diffraction, the

N. F. Magalhães; C. T. Andrade

2009-01-01

389

Orthotropic structural analysis of short fiber filled thermoplastics: Abaqus - Moldflow interface, Experimental validation  

Microsoft Academic Search

Fiber-filled injection-molded parts contain complex fiber orientation patterns depending on the flow kinetics and the molding parameters. This fiber orientation state affects material properties including elastic modulus and strength and part properties including shrinkage and warpage. This requires anisotropic\\/orthotropic structural analysis, as isotropic analysis for these fiber-filled thermoplastics would generally yield inaccurate results. In this work, we report a problem

Ashok K Kancharla; Harindranath Sharma K; Paul Nugent

390

Binary blends of a new wholly aromatic thermoplastic polyimide and poly(ether imide)  

Microsoft Academic Search

This present investigation deals with the miscibility, phase behaviour and semicrystalline morphology of new thermoplastic polyimide (N-TPI)\\/poly(ether imide) (PEI) blends with different compositions. Melt-quenched amorphous blends were used as the raw materials. The phase behaviour of the blends has been studied by means of differential scanning calorimetry (d.s.c.). It has been found that the following four states develop depending upon

Shi Ping Ma; Toshisada Takahashi

1996-01-01

391

Residual strain development in an AS4\\/PPS thermoplastic composite measured using fibre Bragg grating sensors  

Microsoft Academic Search

This paper demonstrates the use of fibre Bragg grating (FBG) sensors for the measurement of residual strain development during the consolidation of a thermoplastic composite. During the processing of the carbon fibre-reinforced polyphenylene sulphide (AS4\\/PPS) laminate, FBG sensors respond to changes in material state, for example the glass-rubber transition and solid–liquid transition. The sensors also permit the observation of wavelength

Larissa Sorensen; Thomas Gmür; John Botsis

2006-01-01

392

EPDM-based thermoplastic vulcanisates: Crosslinking chemistry and dynamic vulcanisation along the extruder axis  

Microsoft Academic Search

This paper presents new insights in the resole crosslinking chemistry of thermoplastic vulcanisates (TPVs) and in the production of TPVs on extruders. Low-molecular-weight olefins were used in combination with EPDM crosslinking experiments to investigate the resole crosslinking chemistry. The fact that enhanced substitution of the olefin\\/EPDM unsaturation enhances the reactivity towards the resole strongly supports the cationic character of SnCl2-activated

M. van Duin; A. V. Machado

2005-01-01

393

Rheology/Morphology Relationship of Immiscible EPDM/PP Based Thermoplastic Elastomer Blends  

NASA Astrophysics Data System (ADS)

The rheological and morphological properties of non-plasticized/plasticized EPDM/PP based thermoplastic elastomers (TPEs) have been investigated. The addition of a plasticizer reduced the rheological properties of both components and their blends and increased their deformability. Complex morphological features (e.g., specific interfacial area and its orientation) of these blends have been analyzed after multiple start-up experiments using atomic force microscopy.

Shahbikian, S.; Carreau, P. J.; Heuzey, M. C.; Ellul, M. D.; Nadella, H. P.; Cheng, J.; Shirodkar, P.

2008-07-01

394

Predicting the tensile modulus and strength of single and hybrid natural fibre reinforced thermoplastic composites  

Microsoft Academic Search

Natural fibre reinforced thermoplastics (NFRT) are used in a variety of commercial applications, but there is little theoretical modeling of structure\\/property relationships in these materials. In this thesis, micromechanical models available in the short-fibre literature were adapted to predict the tensile modulus and strength of some NFRT formulations. Hemp, 20 and 40-mesh hardwood, rice hulls and E-glass fibres were blended

Angelo George Facca

2007-01-01

395

Study on Flame-Retardant LLDPE\\/EPDM Thermoplastic Elastomers with Magnesium Hydroxide Sulfate Hydrate Whiskers  

Microsoft Academic Search

The mechanical properties and flame retardancy of linear low-density polyethylene\\/ethylene-propylene-diene terpolymer thermoplastic elastomers (TPEs) containing magnesium hydroxide sulfate hydrate (MHSH) whiskers and their corresponding un-vulcanized blends (UVBs) were evaluated using static tensile measurements, cone calorimetry and limiting oxygen index (LOI) tests. TPEs exhibited better fire-resistant properties in reducing peak heat release rate and improving LOI values to UVBs. Scanning electron

Hongdian Lu; Jianguo Shao; Ming Ding; Difang Zhao; Changan Tian

2012-01-01

396

Experimental determination of friction coefficients between thermoplastics and rapid tooled injection mold materials  

Microsoft Academic Search

Purpose – To determine static friction coefficients between rapid tooled materials and thermoplastic materials to better understand ejection force requirements for the injection molding process using rapid-tooled mold inserts. Design\\/methodology\\/approach – Static coefficients of friction were determined for semi-crystalline high-density polyethylene (HDPE) and amorphous high-impact polystyrene (HIPS) against two rapid tooling materials, sintered steel with bronze (LaserForm ST-100) and stereolithography

Mary E. Kinsella; Blaine Lilly; Benjamin E. Gardner; Nick J. Jacobs

2005-01-01

397

The application of non-Gaussian chain statistics to ultralow density polyethylenes and other thermoplastic elastomers  

Microsoft Academic Search

A conventional rubber elasticity equation based on the inverse Langevin function, combined with a yield stress (Y0) has been used for the purpose of studying published tensile stress–strain curves for thermoplastic elastomers. In order to simplify the calculation a Pade approximation has been employed [Cohen A. Rheol. Acta. 1991;30:270] for the inverse Langevin function which leads to the following equation,

R. N. Haward

1999-01-01

398

Analysis of weathering of thermoplastic polyester elastomers—I. Polyether-polyester elastomers  

Microsoft Academic Search

Thermoplastic polyester elastomers (TPEE) are useful as new materials covering the region between rubbers and plastics. At present, the uses under outdoor conditions have increased. However, weatherability of TPEE is not clear. We have studied weathering of TPEE, by means of GPC, TG\\/DTA, FT-IR and 1H-NMR and other methods. In conclusion, (1) Ether parts of the soft segment in the

Yasutaka Nagai; Takahiro Ogawa; Liu Yu Zhen; Yuko Nishimoto; Fujio Ohishi

1997-01-01

399

Preparation of a new dialdehyde starch derivative and investigation of its thermoplastic properties  

Microsoft Academic Search

In order to obtain thermoplastic starch plastics with improved properties, a novel method of starch modification was developed\\u000a in this study. Starch derivatives were prepared using the following procedures: pea starch was first oxidized to make dialdehyde\\u000a starch (DAS) by sodium periodate under mild conditions, and this was then acetalized with glycol to give Gly-ADS. The modified\\u000a starch was characterized

Shui-Dong Zhang; Xiu-Li Wang; Yu-Rong Zhang; Ke-Ke Yang; Yu-Zhong Wang

2010-01-01

400

The reclaiming of butyl rubber and in-situ compatibilization of thermoplastic elastomer by power ultrasound  

Microsoft Academic Search

This is a study of the continuous ultrasound aided extrusion process for the in-situ compatibilization of isotactic polypropylene (iPP)\\/ethylene-propylene diene rubber (EPDM) thermoplastic elastomer (TPE) using a newly developed ultrasonic treatment reactor. The rheological, mechanical properties and morphology of the TPE with and without ultrasonic treatment were studied. In-situ compatibilization in the ultrasonically treated blends was observed as evident by

Wenlai Feng

2004-01-01

401

Microstructure-based deep-drawing simulation of knitted fabric reinforced thermoplastics by homogenization theory  

Microsoft Academic Search

Process simulation of fiber reinforced composite materials is an important research theme for the development of low-cost and advanced functional composite materials. This paper aims at the simulation of deep-drawing process of knitted fiber reinforced thermoplastics and its verification. The feature of the simulation is that the large deformation of the knitted microstructures can be traced everywhere in the deep-drawn

N. Takano; Y. Ohnishi; M. Zako; K. Nishiyabu

2001-01-01

402

Preparation and characterization of thermoplastic polyurethane-urea and carboxylated acrylonitrile butadiene rubber blend nanocomposites  

Microsoft Academic Search

This study deals with the preparation and characterization of novel thermoplastic polyurethane-urea (TPUU) and carboxylated acrylonitrile butadiene rubber (XNBR) blends. Blends of different compositions were prepared in tetrahydrofuran using a solution technique, following an ultra-sonication. The chemical reaction between the two inherently immiscible blend phases was determined with the help of Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy and H-1-nuclear

N. Mahmood; A. U. Khan; Z. Ali; M. S. Khan; A. U. Haq; K. W. Stöckelhuber; U. Gohs; G. Heinrich

2012-01-01

403

Fatigue failure characterisation of resistance-welded thermoplastic composites skin\\/stringer joints  

Microsoft Academic Search

An experimental investigation characterising the fatigue failure mechanisms of resistance-welded thermoplastic composites skin\\/stringer joints is presented. Unidirectional (UD) and quasi-isotropic adherends were welded using stainless steel meshes as heating elements. The specimen geometry consisted of a flange laminate, representing a stringer, welded onto a skin laminate. In order to avoid current leakage to the electrically conductive adherends, a ceramic-coated heating

M. Dubé; P. Hubert; A. Yousefpour; J. Denault

2009-01-01

404

Modelling the spot shape influence on high-speed transmission lap welding of thermoplastics films  

Microsoft Academic Search

Modelling high-speed laser lap welding of thermoplastic films has been accomplished and the influence of laser beam spot shape, dimensions, and position relative to sample displacement was analysed.Engineering parameters predicted by the model were applied to lap weld of high- and low-density polyethylene transparent samples with thickness between 10 and 100?m, and experimentally validated. Experimental set-up allowed reaching welding constant

João M. P. Coelho; Manuel A. Abreu; F. Carvalho Rodrigues

2008-01-01

405

Increased isotransferrin ratio and reduced erythrocyte and platelet volumes in blood from thermoplastic industry workers.  

PubMed

Ten women (aged 31-61 years) and five men (aged 20-59 years) occupationally exposed to welding fumes of polyacetate containing diethylphthalate in a thermoplastic industry were studied. They had been employed 1-33 years (median: 11 years). Seven women (aged 35-55) and eight men (aged 26-73) acted as unexposed controls. The exposed persons showed increased isotransferrin ratio in blood serum and reduced volumes of erythrocytes and platelets in blood. PMID:2240993

Beving, H F; Petrén, S; Vesterberg, O

1990-08-01

406

Metal mesh heating element size effect in resistance welding of thermoplastic composites  

Microsoft Academic Search

The objective of this work is to determine the effects of metal mesh heating element size on resistance welding of thermoplastic composites. The materials to be resistance-welded consisted of carbon fiber\\/poly-ether-ketone-ketone (CF\\/PEKK), carbon fiber\\/poly-ether-imide (CF\\/PEI) and glass fiber\\/PEI (GF\\/PEI). Four different metal mesh sizes were used as heating elements. The samples were welded in a lap shear joint configuration and

Martine Dubé; Pascal Hubert; Jan NAH Gallet; Darko Stavrov; Harald EN Bersee; Ali Yousefpour

2012-01-01

407

Development of ACP reinforced thermoplastic composites as an alternative to open mold processing  

NASA Astrophysics Data System (ADS)

Thermoplastic/foam/glass composite technology provides a method of producing large structural parts without styrene or volatile organic compounds (VOCs). High-quality parts can be molded at a low cost by combining vacuum forming technology with a low-pressure urethane reinforcement technique. This process eliminates atomization of paint or gelcoats, styrene emissions from FRP, and associated solvents and chemicals required in the normal processing of fiberglass. Secondary operations also can be streamlined by parts consolidation in the reinforcement process.

O'Neill, Michael A.

1992-01-01

408

Modelling of heat transfer in thermoplastic composites manufacturing: double-belt press lamination  

Microsoft Academic Search

The process of double-belt press lamination of thermoplastic composite laminates has been modelled in terms of heat transfer and crystallization kinetics. Modelling includes temperature dependent thermal properties and non-infinite contact conductances at material interfaces. Model predictions have been compared with experimental results from double-belt press lamination of a sandwich-like glass reinforced polyethylene terephthalate (PET) material. A model for prediction of

A. Trende; B. T. Åström; A. Wöginger; C. Mayer; M. Neitzel

1999-01-01

409

Impact-damaged graphite-thermoplastic trapezoidal-corrugation sandwich and semi-sandwich panels  

Microsoft Academic Search

The results of a study of the effects of impact damage on compression-loaded trapezoidal-corrugation sandwich and semi-sandwich graphite-thermoplastic panels are presented. Sandwich panels with two identical face sheets and a trapezoidal corrugated core between them, and semi-sandwich panels with a corrugation attached to a single skin are considered in this study. Panels were designed, fabricated and tested. The panels were

D. Jegley

1993-01-01

410

Talc-thermoplastic compounds: particle orientation in flow and rheological properties  

Microsoft Academic Search

We describe an investigation of the orientation of talc particles in flow and the rheological properties of talc-thermoplastic compounds. The orientation of talc particles in samples removed from rheometers was determined using a wide angle X-ray diffraction technique. Talc particles, being disc-like in shape, orient with the disc normals perpendicular to the flow direction in the sandwich, cone-plate, parallel plate,

Chang Ho Suh; James L White

1996-01-01

411

Through-transmission ultrasonics for on-line sensing and control of thermoplastic fusion bonding processes  

Microsoft Academic Search

The focus of this work is to develop Through-Transmission Ultrasonics (TTU) as a process monitoring technique for non-intrusive, on-line control of thermoplastic fusion bonding. A model is developed to predict the TTU amplitude of a fusion bond by joining the theory of ultrasonic wave propagation through multilayered structures with a model for the evolution of intimate contact at the material

Kirk David Tackitt

1999-01-01

412

LDPE-based thermoplastic elastomers containing ground tire rubber with and without dynamic curing  

Microsoft Academic Search

Attempts were made to use a ground tire rubber (GTR) fraction (particle size: 0.4–0.7 mm) to produce thermoplastic elastomers (TPEs) composed of low-density polyethylene (LDPE), fresh rubber and GTR with and without dynamic curing. GTR has been thermomechanically decomposed in the presence (GTRPM) and absence of processing oil (GTRM) and its decomposition was followed by the increase in the acetone-soluble

C. Radhesh Kumar; I Fuhrmann; J Karger-Kocsis

2002-01-01

413

Electrostatic spray deposition (ESD) of polymeric powders on thermoplastic (PA66) substrate  

Microsoft Academic Search

This paper deals with a primerless electrostatic spray deposition process (ESD) for coating thermoplastic (PA66) substrates using epoxy–polyester, metallic epoxy–polyester, and epoxy powder paint. A novel and never before used pretreatment system, based on a low speed cold spray of fine copper powders, applied a thin conductive film on the plastic substrate, which made the ESD possible.The focus of first

M. Barletta; A. Gisario; V. Tagliaferri

2006-01-01

414

Synthesis and characterization of aryl phosphine oxide containing thermoplastic polyimides and thermosetting polyimides with controlled reactivity  

NASA Astrophysics Data System (ADS)

Phosphorus containing monomers, bis(3-aminophenyl)methyl phosphine oxide (m-DAMPO) and bis(3-aminophenyl)phenyl phosphine oxide (m-DAPPO), were synthesized and incorporated into a thermoplastic poly(arylene ether imide) based upon 2,2sp'-bis (4-(3,4-dicarboxyphenoxy)phenyl) propane dianhydride and 1,3-phenylene diamine, in order to study their influence on flame resistance and other properties. DAMPO or DAPPO were quantitatively incorporated in concentrations of 25, 50, 75 and 100 mole percent, using the "one pot" ester-acid method. The number average molecular weights of the prepared materials were controlled to 20,000g/mol by off-setting the stoichiometry and endcapping with phthalic anhydride. This strategy enabled one to distinguish the effects of the phosphine oxide incorporation from the influence of molecular weight. The resulting copolymers demonstrated a significant increase in char yield as a function of the phosphine oxide content, thus suggesting improved fire resistance. Glass transition temperatures similar to the control were determined by DSC analysis. Analysis of the mechanical behavior of the DAMPO system at room temperature showed that tensile strength and elongation at failure values were comparable to the control system, while the DAPPO containing copolymers were surprisingly brittle. The influence of the reactive endgroup on the synthesis, cure behavior and network properties of thermosetting polyetherimides was investigated. Reactive phenylacetylene, acetylene and maleimide terminated poly(ether imide) oligomers were prepared and characterized. Optimal reaction conditions were established to produce fully endcapped oligomers with imidized structures and controlled molecular weight. The phenylacetylene endcapped system was synthesized by a conventional ester-acid method. The acetylene endcapped system was prepared via modified ester-acid method and the maleimide endcapped system was fabricated utilizing an amic-acid route. It was determined that phenylethynyl endcapped polymers could be thermally cured at high temperatures (350{-}380sp°C) providing good processibility. The networks exhibited thermal stability, chemical resistance and good adhesion strength, ideal as "primary" bonding adhesives. Acetylene and maleimide endcapped systems were prepared for application as "secondary" bonding materials, meaning that they are cured at a lower temperature than that of the Tg of the primary structure. Lap shear test results indicated good adhesion to titanium when cured at 250sp° C{-}280sp° C. The cured materials showed high glass transition temperatures and good thermal and thermo-oxidative stability as determined by DSC, TGA and DMA. Good chemical resistance was demonstrated via solvent extraction measurements. The influence of molecular weight between crosslinks (/line{M}sb{c}) on thermal and mechanical behavior was also investigated. Lower molecular weight oligomers exhibited lower Tg and cure temperatures, whereas the cured networks resulting from lower molecular weight oligomers afforded higher Tg and higher gel fractions, but reduced toughness.

Zhuang, Hong

1998-11-01

415

Polymer adsorption  

NASA Astrophysics Data System (ADS)

The aim of this talk is to review Pierre-Gilles deGennes' work on polymer adsorption and the impact that it has now in our understanding of this problem. We will first present the self-consistent mean-field theory and its applications to adsorption and depletion. De Gennes most important contribution is probably the derivation of the self-similar power law density profile for adsorbed polymer layers that we will present next, emphasizing the differences between the tail sections and the loop sections of the adsorbed polymers. We will then discuss the kinetics of polymer adsorption and the penetration of a new polymer chain in an adsobed layer that DeGennes described very elegantly in analogy with a quantum tunneling problem. Finally, we will discuss the role of polymer adsorption for colloid stabilization.

Joanny, Jean-Francois

2008-03-01

416

Natural Polymers  

NSDL National Science Digital Library

Polymers that exist in nature, called biopolymers , include a large and diverse range of compounds. This chapter discusses the most important types of natural polymers--their chemical makeup, key properties, and where they are found. The focus will be more on the chemical and physical properties of natural polymers and less on their biological synthesis or physiological function. The references at the end of the chapter provide additional information.

Teegarden, David

2004-01-01

417

Polymer Electrolytes  

NASA Astrophysics Data System (ADS)

This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

Hallinan, Daniel T.; Balsara, Nitash P.

2013-07-01

418

Radiation cross-linked polymers: Recent developments and new applications  

NASA Astrophysics Data System (ADS)

The purpose of the present paper is to review the innovative and recent applications of radiation cross-linking of polymers that reinforces their dimensional stability in chemically aggressive and high temperature conditions. Radiation cross-linking can be applied to a great number of plastics: thermoplastics, elastomers and thermoplastic elastomers (TPE). Some of them can cross-link on their own, some others need to be formulated with a cross-linking agent (promoter) or to be modified during their polymerization. Some results of chemical and thermomechanical characterizations of radiation cross-linked plastics based on engineering polymers will be described, and their advantages will be emphasized in relation with their applications in various sectors: pipes and cables, packaging, automotive, electrical engineering and electronics, including connectors, surface mounted devices, integrated circuits, 3D-MID technology, etc. The paper will conclude with a short review of the industrial irradiation facilities (EB facilities and gamma plants) adapted to the treatment of such various products.

Rouif, Sophie

2005-07-01

419

Injection molded polymer optics in the 21st Century  

NASA Astrophysics Data System (ADS)

Precision polymer optics, manufactured by injection molding techniques, has been a key enabling technology for several decades now. The technology, which can be thought of as a subset of the wider field of precision optics manufacturing, was pioneered in the United States by companies such as Eastman Kodak, US Precision Lens, and Polaroid. In addition to suppliers in the U.S. there are several companies worldwide that design and manufacture precision polymer optics, for example Philips High Tech Plastics in Europe and Fujinon in Japan. Designers who are considering using polymer optics need a fundamental understanding of exactly how the optics are created. This paper will survey the technology and processes that are employed in the successful implementation of a polymer optic solution from a manufacturer's perspective. Special emphasis will be paid to the unique relationship between the molds and the optics that they produce. We will discuss the key elements of production: molding resins, molds and molding equipment, and metrology. Finally we will offer a case study to illustrate just how the optics designer carries a design concept through to production. The underlying theme throughout the discussion of polymer optics is the need for the design team to work closely with an experienced polymer optics manufacturer with a solid track record of success in molded optics. As will be seen shortly, the complex interaction between thermoplastics, molds, and molding machines dictates the need for working closely with a supplier who has the critical knowledge needed to manage all aspects of the program.

Beich, William S.

2005-08-01

420

Hydrophobic corn starch thermoplastic films produced by plasma treatment.  

PubMed

Polymer coating technology is currently an important field in science as it can lead to final products with enhanced characteristics characterized by desired bulk and surface properties. Low power plasmas can induce the polymerization of a precursor gas on the substrate surface as well as introduce functional groups under specific plasma conditions. In the present work, we studied the possibility of reducing water sensitivity of corn starch films by sulfur hexafluoride (SF(6)) plasma treatment. Confocal laser microscopy as well as atomic force microscopy was used to observe the main surface modifications and results indicated starch cross-linking. Fluoride was incorporated to the surface and the relationship between fluoride and sulfur incorporation to the surface was very much dependent on plasma power. Results indicate that fluoride could be preferentially incorporated on polymeric surfaces at -100V self-bias and the overall surface morphology determined the measured contact angle. The dynamic behavior of surface contact angle was observed to be very much dependent on the treatment time and force-distance curves were used to further characterize the chemical surface modifications locally. Optimized treatment conditions led to water contact angles up to 130 degrees . Even after being in contact with water for 10min, surfaces remained hydrophobic, presenting contact angles over 100 degrees . PMID:19345017

Bastos, Daniele C; Santos, Anastácia E F; da Silva, Monica L V J; Simão, Renata A

2009-03-19

421

Polymers All Around You!  

ERIC Educational Resources Information Center

Background information on natural polymers, synthetic polymers, and the properties of polymers is presented as an introduction to this curriculum guide. Details are provided on the use of polymer products in consumer goods, polymer recycling, polymer densities, the making of a polymer such as GLUEP, polyvinyl alcohol, dissolving plastics, polymers

Gertz, Susan

422

Polymer flooding  

Microsoft Academic Search

This book covers all aspects of polymer flooding, an enhanced oil recovery method using water soluble polymers to increase the viscosity of flood water, for the displacement of crude oil from porous reservoir rocks. Although this method is becoming increasingly important, there is very little literature available for the engineer wishing to embark on such a project. In the past,

Littmann

1988-01-01

423

Polymers & People  

ERIC Educational Resources Information Center

|Each Tuesday during the fall of 2002, teams of high school students from three South Carolina counties conducted a four-hour polymer institute for their peers. In less than two months, over 300 students visited the Charleston County Public Library in Charleston, South Carolina, to explore DNA, nylon, rubber, gluep, and other polymers. Teams of…

Lentz, Linda; Robinson, Thomas; Martin, Elizabeth; Miller, Mary; Ashburn, Norma

2004-01-01

424

Polymer Informatics  

NASA Astrophysics Data System (ADS)

Polymers are arguably the most important set of materials in common use. The increasing adoption of both combinatorial as well as high-throughput approaches, coupled with an increasing amount of interdisciplinarity, has wrought tremendous change in the field of polymer science. Yet the informatics tools required to support and further enhance these changes are almost completely absent. In the first part of the chapter, a critical analysis of the challenges facing modern polymer informatics is provided. It is argued, that most of the problems facing the field today are rooted in the current scholarly communication process and the way in which chemists and polymer scientists handle and publish data. Furthermore, the chapter reviews existing modes of representing and communicating polymer information and discusses the impact, which the emergence of semantic technologies will have on the way in which scientific and polymer data is published and transmitted. In the second part, a review of the use of informatics tools for the prediction of polymer properties and in silico design of polymers is offered.

Adams, Nico

425

Phenylene ring dynamics in phenoxy and the effect of intramolecular linkages on the dynamics of some engineering thermoplastics below the glass transition temperature  

NASA Astrophysics Data System (ADS)

We have investigated the dynamics of phenylene rings in the engineering thermoplastic bisphenol-A poly(hydroxyether)—phenoxy—below its glass transition temperature by means of neutron scattering techniques. A relatively wide dynamic range has been covered thanks to the combination of two different types of neutron spectrometers, time of flight and backscattering. Partially deuterated samples have been used in order to isolate the phenylene ring dynamics. The resulting neutron scattering signal of phenoxy has been described by a model that considers ? flips and oscillation motions for phenylene rings. The associated time scales are broadly distributed with mean activation energies equal to 0.41 and 0.21eV , respectively. Finally, a comparative study with the literature shows that the dielectric and mechanical ? relaxation in phenoxy exhibit good correlation with the characteristic times of the aliphatic chain published elsewhere and with the characteristic times observed for the motion of phenylene rings by neutron scattering. These findings are discussed in a more general framework that considers, in addition, previous results on other polymers, which also contain the bisphenol-A unit.

Arrese-Igor, Silvia; Arbe, Arantxa; Alegría, Angel; Colmenero, Juan; Frick, Bernhard

2007-05-01

426

Characterization of the morphology of co-extruded, thermoplastic/rubber multi-layer tapes.  

PubMed

Tapes with alternating semi-crystalline thermoplastic/rubber layers with thicknesses varying from 100 nm up to several microm were prepared by multi-layer co-extrusion. The variation in layer thickness was obtained by varying the thermoplastic/rubber feed ratio. A systematic study on the use of various microscopy techniques to visualize the morphology of the layered systems is presented. The relatively large length scales and the sample preparation make optical microscopy (OM) unsuitable to study the morphology of the multi-layer tapes. Although excellent contrast between the thermoplastic and rubber layers can be obtained, the usually applied, relatively large magnifications limit the use of transmission electron microscopy (TEM) and atomic force microscopy (AFM) to small sample areas. The large range of applicable magnifications makes scanning electron microscopy (SEM) the most suitable technique to study the morphology of the multi-layer tapes. The sample preparation for SEM with a secondary electron (SE) detector is often based on the removal of one of the components, which may induce changes in the morphology. SEM with a back-scattered electron (BSE) detector is a very convenient method to study the morphology over a wide range of length scales, where the contrast between the different layers can be enhanced by chemical staining. Finally, the nucleation behavior (homogeneous versus heterogeneous) of the semi-crystalline layers, as probed by differential scanning calorimetry (DSC), provides valuable information on the layered morphology. The use of relatively straightforward DSC measurements shows a clear advantage with respect to the discussed microscopy techniques, since no sample preparation is required and relatively large samples can be studied, which are more representative for the bulk. PMID:19850162

l'Abee, R M A; Vissers, A M J T; Goossens, J G P; Spoelstra, A B; van Duin, M

2009-06-21

427

The development of polymer layers for vibration damping steel sheet  

NASA Astrophysics Data System (ADS)

The characterization of damping resins, and the forming characteristics of vibration damping steel sheets were carried out in order to evaluate polymer layers for vibration damping steel sheets. The bonding strength and damping properties depend on the chemical nature of individual polymers on the vibration damping steel sheets. Polyester-based thermoplastic polymer shows the best performance. Damping characteristics of vibration damping steel sheet can be well predicted from the dynamic loss factor of resins via the WLF equation. The vibration damping properties of polymers can be changed by a plasticizer. It was found that the service temperature of polymer generally decreased using an increasing amount of plasticizer. It is concluded that the vibration damping steel sheet made by the loss factor greater than 0.1 in the range of normal service temperature as well as the tensile shear strength greater than 80 kgf/cm2 at room temperature and the addition of Ni powder have been found to improve weldability the same an ordinary steel sheet. [Work supported by POSCO.

Oh, T. S.; Ryou, J. H.

2002-11-01

428

Interferometric measurement of the transverse strain response of electroactive polymers  

NASA Astrophysics Data System (ADS)

Some electroactive polymers produce large electric-field-induced strains that can be used for electromechanical actuation. The measurement of the strain response, especially the dynamic response under high driving fields, is difficult. We have developed a transverse strain measurement system based on the Zygo laser Doppler interferometer. The system can measure transverse strain responses of polymer samples of different sizes over a wide displacement range and a frequency range from DC up to 100 Hz. We have used this interferometric system to investigate the strain response of Maxwell stress actuators fabricated from silicone (Dow Corning HS III RTV) and thermoplastic polyurethane (Dow Pellethane 2103) films. The static and dynamic strain responses of the materials to a variety of driving electric fields such as step fields, AC fields and DC bias fields have been measured as functions of amplitude and frequency. The strain response has a quadratic relationship with the driving field and shows a strong dependence on the frequency of the applied field. Of the two kinds of polymers investigated, HS III silicone polymer shows higher strain and breakdown fields. High transverse strains of 3.25 % (static) and 2.08 % (dynamic at 1 Hz) for HS III silicone polymers have been obtained. In addition, the effect of mechanical tensile load on the transverse strain has also been studied. The experimental data are interpreted in terms of measured material properties and small strain models for dielectric film actuators.

Ren, Wei; Yang, Guomao; Mukherjee, Binu K.; Szabo, Jeffrey P.

2004-07-01

429

Two-dimensional metallic nanobowl array transferred onto thermoplastic substrates by microwave heating of carbon nanotubes  

NASA Astrophysics Data System (ADS)

The unique heating property of microwave irradiation on carbon nanotubes (CNTs) was applied in fabrication of a new architecture of two-dimensional metallic nanobowl array on a thermoplastic substrate. Vertically aligned CNT film was grown on a metal coated polystyrene (PS) submicron sphere array and then transferred onto a polycarbonate (PC) substrate by microwave heating. The back diffracted light spectra of this structure were measured and discrepancies between the spectra and that predicted from a diffraction relationship were studied. It is suggested that the discrepancies were related to the shape and the refractive indices of the materials.

Chen, Tsung-Han; Tsai, Tsung-Yen; Hsieh, Kun-Che; Chang, Shih-Chin; Tai, Nyan-Hwa; Chen, Hsuen-Li

2008-11-01

430

Macroscopic thermoplastic model applied to the high pressure torsion of metallic glasses  

SciTech Connect

Shear deformation generated temperature rise in metallic glasses is estimated in a macroscopic three-dimensional axial symmetric thermoplastic model. Numerical solution of heat-conduction equation provides the time evolution and spatial distribution of temperature for high pressure torsion in the present paper. We have shown that small sample thickness and/or high deformation rate enables the temperature to exceed the glass transition in the entire sample, yielding a transition of the deformation mode from inhomogeneous to homogeneous viscous flow. However, in other cases only a small temperature increase is predicted in line with literature data.

Hobor, Sandor; Revesz, Adam [Department of Materials Physics, Eoetvoes University, P.O. Box 32, Budapest H-1518 (Hungary); Kovacs, Zsolt [Department of Materials Physics, Eoetvoes University, P.O. Box 32, Budapest H-1518 (Hungary); School of Electrical, Electronic and Mechanical Engineering, University College Dublin, Belfield, Dublin 4 (Ireland)

2009-07-15

431

TECHNIQUES AND RESULTS FOR FIBER LENGTH DISTRIBUTION DETERMINATION AS A FUNCTION OF THICKNESS IN LONG FIBER REINFORCED INJECTION MOLDED THERMOPLASTICS  

SciTech Connect

A novel measurement technique was developed to obtain unbiased fiber length distribution (FLD) measurements at specified locations in the thickness of the sample. This technique relies on elastic energy stored in long fiber thermoplastics (LFT), which is released during partially constrained burn-off. This release results in an increase of thickness dimension of the sample and partial disentanglement, allowing sample selection and subsequent filament separation. Quantitative FLD results and the measurement technique are discussed in detail. The FLD in long fiber reinforced injection molded thermoplastics is shown to vary as a function of thickness.

Kunc, Vlastimil [ORNL; Frame, Barbara J [ORNL; Pryor, Jeff M [ORNL; Nguyen, Ba N. [Pacific Northwest National Laboratory (PNNL); TuckerIII, Charles L. [University of Illinois, Urbana-Champaign; Case, Scott [Virginia Polytechnic Institute and State University; Penumadu, Dayakar [University of Tennessee, Knoxville (UTK); Guffey, Eric W [University of Tennessee, Knoxville (UTK)

2008-01-01

432

Polymers All Around You!  

ERIC Educational Resources Information Center

|Background information on natural polymers, synthetic polymers, and the properties of polymers is presented as an introduction to this curriculum guide. Details are provided on the use of polymer products in consumer goods, polymer recycling, polymer densities, the making of a polymer such as GLUEP, polyvinyl alcohol, dissolving plastics,…

Gertz, Susan

433

Microgravity Polymers.  

National Technical Information Service (NTIS)

A one-day, interactive workshop considering the effects of gravity on polymer materials science was held in Cleveland, Ohio, on May 9, 1985. Selected programmatic and technical issues were reviewed to introduce the field to workshop participants. Parallel...

1986-01-01

434

Organometallic Polymers.  

ERIC Educational Resources Information Center

Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

Carraher, Charles E., Jr.

1981-01-01

435

Production and characterization of thermoplastic cassava starch, functionalized poly(lactic acid), and their reactive compatibilized blends  

NASA Astrophysics Data System (ADS)

Cassava starch was blended with glycerol using a co-rotating twin-screw extruder (TSE). Thermoplastic cassava starch (TPCS) at a ratio of 70/30 by weight of cassava/glycerol was selected and further blended with other polymers. TPCS sheets made from compression molding had low tensile strength (0.45 +/- 0.05 MPa) and Young's modulus (1.24 +/- 0.58 MPa), but moderate elongation at break (83.0 +/- 0.18.6%), medium level of oxygen permeability, and high water vapor permeability with a very high rate of water absorption. TPCS was blended with poly(lactic acid) (PLA) at various ratios by using a TSE. The blend resins exhibited good properties such as increased thermal stability (Tmax) and crystallinity of PLA, and improved water sensitivity and processability of TPCS. PLA and TPCS exhibited a high interfacial tension between the two phases of 7.9 mJ·m -2, indicating the formation of an incompatible, immiscible blend. SEM micrographs showed a non-homogeneous distribution of TPCS droplets in the PLA continuous phase. TEM micrographs of the blend films made by cast-film extrusion showed coalescence of the TPCS droplets in the PLA continuous phase of the blend, indicating that the compatibility between the polymer pair needs to be improved. A response surface methodology (RSM) design was used to analyze the effects of maleic anhydride (MA) and 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (Luperox or L101) contents, and TSE screw speed on the degree of grafted MA and number average molecular weight (Mn) of functionalized PLA (PLA-g-MA), a reactive compatibilizer. PLA-g- MA made by reactive extrusion had an array of colors depending on the content of L101 and MA used. New FTIR peaks suggested that MA was grafted onto the PLA backbone and oligomeric MA may occur. Increasing L101 increased the degree of grafting and decreased Mn, but the Mn of the PLA-g-MA's produced with a high amount of L101 was stable during storage. MA exhibited an optimum concentration for maximizing the degree of grafted MA, and increasing MA content retarded the reduction of Mn during processing. However, the Mn of PLA-g-MA during storage decreased more rapidly with a high content of MA. TSE screw speed had an impact on the Mn with the maximum value predicted at 20 rpm. PLA-g-MA compounds differing in Mn and/or grafted MA content were used as reactive polymers with TPCS (to produce binary blends) and as reactive compatibilizers (to produce ternary blends of PLA/TPCS/PLA-g-MA) with TPCS content of 30 wt% using a TSE. As a result of maleation, PLA-g-MA had a higher grafted MA content with a lower Mn, and higher PI. The interaction of anhydride groups from PLA-g-MA and hydroxyl groups from TPCS was found by FTIR. The reactive binary blends exhibited a change in thermal stability, decrease of Tcc, the presence of double melting peaks, and an increase of the Tgs of glycerol and starch. The higher the grafted MA content and/or the higher Mn of the PLA- g-MA used, the better were the distribution and smaller the TPCS domains obtained in the blends. The highest elongation at break was achieved when 30 wt% TPCS was blended with 70 wt% of PLA having 0.1 wt% of grafted MA and Mn of PLA-g-MA with a 45 kDa. Finally, the optimum PLA-g-MA was determined by using the results from PLA-g-MA RSM design and the reactive blending.

Detyothin, Sukeewan

436

Polymer batteries  

NASA Astrophysics Data System (ADS)

This paper presents a state-of-the-art report on polymer battery development. The research and development activities related to materials of construction for battery components, i.e., anode, electrolyte, and cathode are reviewed. Major achievements have been accomplished in the last decade and the progress is very encouraging. Some potential problems have been identified and these problems may require significant development efforts before polymer batteries become a commercial reality.

Kumar, Binod; Marsh, Richard A.

1991-04-01

437

Polymer Synthesis  

NSDL National Science Digital Library

In the first four chapters, we have seen that many different kinds of polymers exist and that they have an extremely wide range of properties. Some are stiff, others are soluble, while still others are rubbery. There are plastics, and fibers, and adhesives, and foams. The structure and composition of the macromolecule dictate the ultimate properties. Structure and composition are determined when the macromolecule is synthesized. In this chapter we want to understand how monomers react together to form long polymer chains.

Teegarden, David

2004-01-01

438

Polymer/Solvent and Polymer/Polymer Interaction Studies.  

National Technical Information Service (NTIS)

Polymer/polymer and polymer/solvent interaction information can be obtained from solution thermodyanmic studies. In this work, gas chromatography and piezoelectric sorption techniques were used to obtain experimental solution data. A brief review of exper...

J. C. Holste C. J. Glover D. T. Magnuson K. C. Dangayach T. A. Powell

1979-01-01

439

Effect of Polymer Form and its Consolidation on Mechanical Properties and Quality of Glass/PBT Composites  

NASA Astrophysics Data System (ADS)

The aim of this study was to understand the role of the processing in determining the mechanical properties of glass fibre reinforced polybutylene terephthalate composites (Glass/PBT). Unidirectional (UD) composite laminates were manufactured by the vacuum consolidation technique using three different material systems included in this study; Glass/CBT (CBT160 powder based resin), Glass/PBT (prepreg tapes), and Glass/PBT (commingled yarns). The different types of thermoplastic polymer resin systems used for the manufacturing of the composite UD laminate dictate the differences in final mechanical properties which were evaluated by through compression, flexural and short beam transverse bending tests. Microscopy was used to evaluate the quality of the processed laminates, and fractography was used to characterize the observed failure modes. The study provides an improved understanding of the relationships between processing methods, resin characteristics, and mechanical performance of thermoplastic resin composite materials.

Durai Prabhakaran, R. T.; Pillai, Saju; Charca, Samuel; Oshkovr, Simin Ataollahi; Knudsen, Hans; Andersen, Tom Løgstrup; Bech, Jakob Ilsted; Thomsen, Ole Thybo; Lilholt, Hans

2013-09-01

440

An interdisciplinary methodology for the comparative evaluation of splinting materials (orthotics, thermoplastics, clinical research).  

PubMed

The methodology developed includes both the use of laboratory evaluation and clinical assessment in an area where there are no standard requirements, no specifications, nor any continuity of data available on the various thermoplastic splinting materials now on the market. A series of laboratory tests and clinical trials were devised such that these could be interpreted with regard to clinical considerations, cost analyses and serviceability factors relating to the materials. Laboratory testing covered possible effects on the chemical and mechanical properties of material likely to be caused by various environmental, sterilization and working factors. The complementary clinical evaluation to highlight the behaviour of materials during the fabrication and wearing of splints consisted of specific information generated with the assistance of experienced occupational therapists, occupational therapy students and patients. Biocompatibility studies were also carried out. The data to be published will provide needed information to physicians, occupational therapists, physical therapists, orthotists, prosthetists, and administrators with regard to their making informed decisions on the selection, purchase and use of thermoplastic materials. PMID:10255889

Shimeld, A; Campbell, G; Ernest, M

1982-06-01

441

Bio-thermoplastics from grafted chicken feathers for potential biomedical applications.  

PubMed

This research demonstrated the feasibility of using bio-thermoplastics developed from chicken feathers grafted with acrylates and methacrylates as scaffolds for tissue engineering. Keratin, the major protein in feathers, is a highly crosslinked biopolymer that has been reported to be biocompatible. However, it is difficult to break the disulfide bonds and make keratin soluble to develop materials for tissue engineering and other medical applications. Previously, keratin extracted from feathers using alkaline hydrolysis has been made into scaffolds but with poor water stability and mechanical properties. In this study, thermoplastic films were compression molded from chicken feathers grafted with 6 different acrylate monomers. The influence of the concentration and structures of grafted monomers on grafting parameters and the tensile strength, water stability and cytocompatibility of grafted feathers compression molded into films were investigated. It was found that the grafted feather films were water stable and had good strength and better supported cell growth than poly(lactic acid) films. Grafted feathers demonstrated the potential to be used for fabrication of biomaterials for various biomedical applications. PMID:23707850

Reddy, Narendra; Jiang, Qiuran; Jin, Enqi; Shi, Zhen; Hou, Xiuliang; Yang, Yiqi

2013-04-28

442

In situ consolidation for thermoplastic tape placement process is not obvious  

NASA Astrophysics Data System (ADS)

Thermoplastic tape placement process receive a growing interest for its large parts and out of autoclave possibilities. This process is based on the fusion bonding of the thermoplastic matrix. Thanks to a heating source and a compaction roller, a new tape is welded in continuity on the already deposited substrate. To make `good' laminated parts, you need to achieve efficient bonding between material layers, and avoid material degradation. As we want to define a process window for this application, we need to know temperature and pressure, in every point of the part, at every instant of its forming steps. In this work, we propose an original thermal modelling of this problem which takes in account the non perfect thermal transfers existing between material layers to compute the temperature field in the laminate during its forming stage. Because of the specific geometry of the problem (thin tapes with large length way), we propose a numerical resolution with a PGD (Proper Generalized Decomposition) method. The numerical results are validated by experimental measurements. Then thanks to the temperature history, we calculate healing degree, and degradation so as to define a process window.

Barasinski, A.; Leygue, A.; Soccard, E.; Poitou, A.

2011-05-01

443

Method and apparatus for producing composites of materials exhibiting thermoplastic properties  

DOEpatents

A mobile device for the complete consolidation of layers of material which exhibit thermoplastic properties for the formation of a composite of the layers upon a complex contoured substrate. The principal of the device is to provide heating into the molten temperature range of the thermoplastic material, applying sufficient pressure to the layers to cause flow of the plastic for a time sufficient to achieve full consolidation of the layers, and quickly cooling the structure to prevent delamination or other non-consolidation action. In the preferred form, there is an element to deposit a layer of the mateiral against another layer in close proximity. The two layers are pre-heated to near the melting temperature, and then further heated into the melting temperature range as they are brought into intimate contact with sufficient pressure to cause flow of the plastic for a time sufficient to achieve the full consolidation. The structure is then cooled. The mechanism for the application of pressure is selected such that the layers can be deformed to conform to a complex contour. In the preferred form, this pressurization is produced using a compliant hood that supplies both the pressure and at least a portion of the melting temperature, as well as the cooling. The apparatus, and method of operation, are described relative to the use of fiber-reinforced PEEK in the making of fully-consolidated composites. Other applications are discussed.

Garvey, Raymond E. (Knoxville, TN); Grostick, Edmund T. (Faragut, TN)

1992-01-01

444

Field Evaluation of the Potential for Creep in Thermoplastic Encapsulant Materials: Preprint  

SciTech Connect

There has been recent interest in the use of thermoplastic encapsulant materials in photovoltaic modules to replace chemically crosslinked materials, e.g., ethylene-vinyl acetate. The related motivations include the desire to: reduce lamination time or temperature; use less moisture-permeable materials; use materials with better corrosion characteristics or with improved electrical resistance. However, the use of any thermoplastic material in a high-temperature environment raises safety and performance concerns, as the standardized tests currently do not expose the modules to temperatures in excess of 85 degrees C, though fielded modules may experience temperatures above 100 degrees C. Here we constructed eight pairs of crystalline-silicon modules and eight pairs of glass/encapsulation/glass thin-film mock modules using different encapsulant materials of which only two were designed to chemically crosslink. One module set was exposed outdoors with insulation on the back side in Arizona in the summer, and an identical set was exposed in environmental chambers. High precision creep measurements (+/- 20 um) and performance measurements indicate that despite many of these polymeric materials being in the melt state during outdoor deployment, very little creep was seen because of their high viscosity, temperature heterogeneity across the modules, and the formation of chemical crosslinks in many of the encapsulants as they aged. In the case of the crystalline silicon modules, the physical restraint of the backsheet reduced the creep further.

Kempe, M. D.; Miller, D. C.; Wohlgemuth, J.; Kurtz, S. R.; Moseley, J. M.; Shah, Q.; Tamizhmani, G.; Sakurai, K.; Inoue, M.; Doi, T.; Masuda, A.; Samuels, S. L.; Vanderpan, C. E.

2012-06-01

445

Method and apparatus for producing composites of materials exhibiting thermoplastic properties  

DOEpatents

A mobile device for the complete consolidation of layers of material which exhibit thermoplastic properties for the formation of a composite of the layers upon a complex contoured substrate. The principal of the device is to provide heating into the molten temperature range of the thermoplastic material, applying sufficient pressure to the layers to cause flow of the plastic for a time sufficient to achieve full consolidation of the layers, and quickly cooling the structure to present delamination or other non-consolidation action. In the preferred form, there is an element to deposit a layer of the material against another layer in close proximity. The two layers are pre-heated to near the melting temperature, and then further heated into the melting temperature range as they are brought into intimate contact with sufficient pressure to cause flow of the plastic for a time sufficient to achieve the full consolidation. The structure is then cooled. The mechanism for the application of pressure is selected such that the layers can be deformed to conform to a complex contour. In the preferred form, this pressurization is produced using compliant hood that supplies both the pressure and at least a portion of the melting temperature, as well as the cooling. The apparatus, and method of operation, are described relative to the use of fiber-reinforced PEEK in the making of fully-consolidated composites. Other applications are discussed.

Garvey, R.E.; Grostick, E.T.

1990-01-01

446

Method and apparatus for producing composites of materials exhibiting thermoplastic properties  

DOEpatents

A mobile device for the complete consolidation of layers of material which exhibit thermoplastic properties for the formation of a composite of the layers upon a complex contoured substrate. The principal of the device is to provide heating into the molten temperature range of the thermoplastic material, applying sufficient pressure to the layers to cause flow of the plastic for a time sufficient to achieve full consolidation of the layers, and quickly cooling the structure to present delamination or other non-consolidation action. In the preferred form, there is an element to deposit a layer of the material against another layer in close proximity. The two layers are pre-heated to near the melting temperature, and then further heated into the melting temperature range as they are brought into intimate contact with sufficient pressure to cause flow of the plastic for a time sufficient to achieve the full consolidation. The structure is then cooled. The mechanism for the application of pressure is selected such that the layers can be deformed to conform to a complex contour. In the preferred form, this pressurization is produced using compliant hood that supplies both the pressure and at least a portion of the melting temperature, as well as the cooling. The apparatus, and method of operation, are described relative to the use of fiber-reinforced PEEK in the making of fully-consolidated composites. Other applications are discussed.

Garvey, R.E.; Grostick, E.T.

1990-12-31

447

High throughput multilayer microfluidic particle separation platform using embedded thermoplastic-based micropumping.  

PubMed

We present an integrated thermoplastic elastomer (TPE) based multilayer microfluidic device with an embedded peristaltic micropump and through-holes membrane for high throughput particle sorting and separation. Fluidic and pneumatic layers of the device were fabricated using hot-embossing lithography and commercially available polycarbonate membranes were succcessfully sandwiched between two thermoplastic elastomer fluidic layers integrated to a peristaltic micropumping layer. The integrated peristaltic micropump induces turbulence at the top-microfluidic layer ring which successfully avoids particle aggregation and membrane blocking even at nanorange size. We present herein the general design of the device structure and pumping characteristics for three devices with membrane pore sizes of 10 ?m, 5 ?m and 800 nm. By using this design we have successfully demonstrated a separation efficiency as high as 99% of polystyrene microbeads with different sizes and most importantly the separation of 390 nm particles from 2 ?m beads was achieved. Using this device, we were also able to separate red blood cells with size of about 6-8 ?m from osteoblasts typically larger than 10 ?m to demonstrate the potential applicability of this platform for biological samples. The produced microfluidic chip operating at flow rates up to 100 ?l min(-1) allows us to achieve efficient high-throughput sorting and separation of target particles/cells. PMID:23640083

Didar, Tohid Fatanat; Li, Kebin; Tabrizian, Maryam; Veres, Teodor

2013-05-03

448

USE OF RECYCLED POLYMERS FOR ENCAPSULATION OF RADIOACTIVE, HAZARDOUS AND MIXED WASTES  

SciTech Connect

Polyethylene encapsulation is a waste treatment technology developed at Brookhaven National Laboratory using thermoplastic polymers to safely and effectively solidify hazardous, radioactive and mixed wastes for disposal. Over 13 years of development and demonstration with surrogate wastes as well as actual waste streams on both bench and full scale have shown this to be a viable and robust technology with wide application. Process development efforts have previously focused on the use of virgin polymer feedstocks. In order to potentially improve process economics and serve to lessen the municipal waste burden, recycled polymers were investigated for use as encapsulating agents. Recycled plastics included low-density polyethylene, linear low-density polyethylene, high-density polyethylene and polypropylene, and were used as a direct substitute for or blended together with virgin resin. Impacts on processing and final waste form performance were examined.

LAGERRAAEN,P.R.; KALB,P.D.

1997-11-01

449

The effect of free radical inhibitor on the sensitized radiation crosslinking and thermal processing stabilization of polyurethane shape memory polymers  

NASA Astrophysics Data System (ADS)

The effects of free radical inhibitor on the electron beam crosslinking and thermal processing stabilization of novel radiation crosslinkable polyurethane shape memory polymers (SMPs) blended with acrylic radiation sensitizers have been determined. The SMPs in this study possess novel processing capabilities—that is, the ability to be melt processed into complex geometries as thermoplastics and crosslinked in a secondary step using electron beam irradiation. To increase susceptibility to radiation crosslinking, the radiation sensitizer pentaerythritol triacrylate (PETA) was solution blended with thermoplastic polyurethane SMPs made from 2-butene-1,4-diol and trimethylhexamethylene diisocyanate (TMHDI). Because the thermoplastic melt processing methods such as injection molding are often carried out at elevated temperatures, sensitizer thermal instability is a major processing concern. Free radical inhibitor can be added to provide thermal stabilization; however, inhibitor can also undesirably inhibit radiation crosslinking. In this study, we quantified both the thermal stabilization and radiation crosslinking inhibition effects of the inhibitor 1,4-benzoquinone (BQ) on polyurethane SMPs blended with PETA. Sol/gel analysis of irradiated samples showed that the inhibitor had little to no inverse effects on gel fraction at concentrations of 0-10,000 ppm, and dynamic mechanical analysis showed only a slight negative correlation between BQ composition and rubbery modulus. The 1,4-benzoquinone was also highly effective in thermally stabilizing the acrylic sensitizers. The polymer blends could be heated to 150 °C for up to 5 h or to 125 °C for up to 24 h if stabilized with 10,000 ppm BQ and could also be heated to 125 °C for up to 5 h if stabilized with 1000 ppm BQ without sensitizer reaction occurring. We believe this study provides significant insight into methods for manipulation of the competing mechanisms of radiation crosslinking and thermal stabilization of radiation sensitizers, thereby facilitating further development of radiation crosslinkable thermoplastic SMPs.

Hearon, Keith; Smith, Sarah E.; Maher, Cameron A.; Wilson, Thomas S.; Maitland, Duncan J.

2013-02-01

450

Monitoring deformation and degradation of fibre reinforced thermoplastic composite material using imbedded Draw Tower fibre Bragg grating sensors and technology  

Microsoft Academic Search

Within this research draw tower fibre Bragg grating sensors will be used for imbedding in fibre reinforced thermoplastic composites. These sensors are based on a new fibre optic technology which allows developing high strength fibre Bragg gratings with a smaller diameter and special coatings. The improvement of these parameters is necessary for the accurate monitoring of the real strains inside

Eli Voet; Joris Degrieck; Hartmut Bartelt

451

Comparison study of QuickCast versus a traditional thermoplastic in the fabrication of a resting hand splint.  

PubMed

Therapists are frequently presented with new splinting material promising better and faster results. Managed care and cost containment make it important to evaluate the splinting materials used in the fabrication process. A new precut splint, QuickCast, is made from a fiberglass material that becomes pliable from the heat of a standard household hair dryer. Graduate occupational therapy students participated in timed trials fabricating resting hand splints with QuickCast and Ezeform brands of thermoplastic. Second-year occupational therapy students chosen as splint makers answered a questionnaire measuring fit, edges, strap application, aesthetics, safety, and ease of positioning. First-year students who had no neurologic or orthopedic involvement in the upper extremities participated as clients. They answered a questionnaire on comfort, weight, and aesthetics of the splint and the safety and comfort of the splinting process. Analysis of timed trials revealed no significant difference in the time required to fabricate the QuickCast precut thermoplastic and the sheet thermoplastic splints. From the questionnaire, the thermoplastic splint was rated safer than the QuickCast material by splint makers. Further studies are suggested for comparing time and cost effectiveness between commercially available splinting materials. PMID:9493798

Lau, C

452

The role of molecular weight and temperature on the elastic and viscoelastic properties of a glassy thermoplastic polyimide  

Microsoft Academic Search

Mechanical testing of the elastic and viscoelastic response of an advanced thermoplastic polyimide (LaRC™-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The notched tensile strength was shown to be a strong function of both molecular weight and temperature, whereas stiffness was only a strong function of temperature. A critical

Lee M. Nicholson; Karen S. Whitley; Thomas S. Gates

2002-01-01

453

Low temperature cure of unsaturated polyester resins with thermoplastic additives III. Modification of polyvinyl acetate for better shrinkage control  

Microsoft Academic Search

Copolymers of vinyl acetate and acid monomers were synthesized by emulsion polymerization and applied as shrinkage control additives in the polymerization of unsaturated polyester (UP) and styrene at low temperatures. The presence of acid groups on the copolymer chain changes the selectivity of the cobalt promoter, and in turn, the relative reaction rate in the thermoplastic-rich and the UP-rich phase

W Li; L. J Lee; K. H Hsu

2000-01-01

454

Development of smooth finishes in electrostatic fluidized bed (EFB) coating process of high-performance thermoplastic powders (PPA 571 H)  

Microsoft Academic Search

This paper deals with the analysis of the evolution of the surface morphology of metal substrates coated with high-performance thermoplastic powders, namely PPA 571 H, by using electrostatic fluidized bed (EFB) process. Attention has been particularly focused on the relationship between baking time and temperature of EFB coated substrates and the morphological characteristics of the resulting polymeric films.First, thermal behaviour

Massimiliano Barletta; Annamaria Gisario; Stefano Guarino; Gianluca Rubino

2006-01-01

455

The Influence of Crysnanoclay Addition on Mechanical and Thermal Properties of Thermoplastic Polyurethane Elastomeric with Polycarbonate Nanocomposites  

Microsoft Academic Search

A series of crysnanoclay-loaded thermoplastic polyurethane (TPU) elastomer\\/polycarbonate (PC) nanocomposites have been prepared using twin screw extruders. The physicomechanical properties such as tensile behaviors, flexural properties and impact strength of the composites have been reported. Significant improvement in tensile modulus and flexural modulus were noticed for nanocomposites. The thermal characteristics of nanocomposites have been determined by thermogravimetric analysis (TGA) techniques.

Shahryar Pashaei; Siddaramaiah; Akheel Ahmed Syed; G. Ramachandra Reddy; S. Srinivasa

2012-01-01

456

Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes  

Microsoft Academic Search

This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT)

Mou'ad A. Tarawneh; Sahrim Hj. Ahmad; S. Y. Yahya; Rozaidi Rasid

2009-01-01

457

Wood Fiber Reinforced Thermoplastics Composites: Effect of Compounding, Molding and Fiber Length on Resulting Properties: Pilot Plant Trials  

Microsoft Academic Search

The reinforcement potential of cellulosic fibers in thermoplastic composites has been studied. Polystyrene polyethylene or polypropylene were combined with cellulosic short fiber substrates. In this study the following substrates were used: CTMP fibers, Sawdust or recycled pulp sludge reject fiber. The effect of fiber loading, fiber length, fiber aspect ratio and fiber type on resulting composite properties has been evaluated

Bohuslav V. Kokta

458

Numerical Analysis of a High Power Piezoelectric Transducer Used in the Cutting and Welding of Thermoplastic Textiles  

Microsoft Academic Search

High power piezoelectric transducers have been used in the ultrasonic cutting and welding of thermoplastic textiles. The acoustical energy generated by a sandwich type power transducer is transferred to an wide blade-shaped horn through an acoustic amplifier. The transmission efficiency depends on the transducer and the horn assembly vibrational behavior. This paper presents a finite element analysis of a high

João Batista da Silva; Nilson Noris Franceschetti; Julio Cezar Adamowski

459

Modelling face-core bonding in sandwich manufacturing: Thermoplastic faces and rigid closed-cell foam core  

Microsoft Academic Search

A model to predict the bond strength between thermoplastic faces and rigid, closed-cell foam cores in structural sandwich components is presented. The model is based on the assumption that the bond strength is proportional to the amount of resin that flows during manufacturing into the open surface cells of the core to bond the constituents to each other. Following model

Malin Åkermo; B. Tomas Åström

1998-01-01

460

Process monitoring of aluminum-foam sandwich structures based on thermoplastic fibre–metal laminates using fibre Bragg gratings  

Microsoft Academic Search

This paper reports the use of fibre Bragg gratings (FBGs) for monitoring the fabrication process in a novel sandwich structure based on thermoplastic fibre–metal laminate (FML) skins and an aluminum-foam core. The FBG sensors were embedded between two plies of glass fibre reinforced polypropylene within the FML and the shift in the Bragg wavelength was recorded during the fabrication cycle

K. S. C. Kuang; L. Zhang; W. J. Cantwell; I. Bennion

2005-01-01

461

Damage monitoring in aluminum-foam sandwich structures based on thermoplastic fibre-metal laminates using fibre Bragg gratings  

Microsoft Academic Search

This paper reports the use of fibre Bragg gratings (FBGs) as sensors for structural integrity assessment by monitoring the reduction in the flexural stiffness of a novel sandwich structure based on thermoplastic fibre-metal laminate (FML) skins and an aluminum-foam core. By monitoring the reduction in the structural flexural stiffness, the technique demonstrated its potential for detecting damage initiation in these

K. S. C. Kuang; W. J. Cantwell; L. Zhang; I. Bennion; M. Maalej; S. T. Quek

2005-01-01

462

Characterization of the Weldline Strength in Terms of Crack Growth Resistance in Injection-Molded Thermoplastic Elastomers  

Microsoft Academic Search

The weldline strength of injection-molded thermoplastic elastomers (TPEs) were determined in terms of crack growth resistance. The specimens were injection molded under identical processing conditions except the cavity surface temperature; one cavity has a cold mold surface of 20°C and the other has a hot mold surface equal to the melt temperature of the TPE, 189°C. These two conditions were

J. Rioux; D. Yao; B. H. Kim

1998-01-01

463

Combinatorial study of a gold nanoparticle infusion process in a polymer film  

Microsoft Academic Search

A novel two-step process is described for infusion of gold nanoparticles (5–20 nm typical diameter) into a polymer film. The\\u000a technique is demonstrated for the first time in a thermoplastic polyurethane elastomer (TPU). An amine-functional monomer,\\u000a 2-(diethylamino)ethyl methacrylate, and a free-radical photoinitiator are infused into the surface of the TPU, followed by\\u000a photopolymerization. An amine-functional semi-interpenetrating network (SIPN) is created

Daniel M. LentzAlicyn; Alicyn M. Rhoades; Robert A. PylesKarl; Karl W. Haider; Mark S. AngeloneRonald; Ronald C. Hedden

464

The Cost of Automotive Polymer Composites: A Review and Assessment of DOE's Lightweight Materials Composites Research  

SciTech Connect

Polymer composite materials have been a part of the automotive industry for several decades, with early application in the 1953 Corvette. These materials have been used for applications with low production volumes, because of their shortened lead times and lower investment costs relative to conventional steel fabrication. Important drivers of the growth of polymer composites have been the reduced weight and parts consolidation opportunities the material offers, as well as design flexibility, corrosion resistance, material anisotropy, and mechanical properties. Although these benefits are well recognized by the industry, polymer composite use has been dampened by high material costs, slow production rates, and to a lesser extent, concerns about recyclability. Also impeding large scale automotive applications is a curious mixture of concerns about material issues such as crash energy absorption, recycling challenges, competitive and cost pressures, the industry's general lack of experience and comfort with the material, and industry concerns about its own capabilities (Flynn and Belzowski 1995). Polymer composite materials are generally made of two or more material components--fibers, either glass or carbon, reinforced in the matrix of thermoset or thermoplastic polymer materials. The glass-reinforced thermoset composites are the most commonly used composite in automotive applications today, but thermoplastic composites and carbon fiber-reinforced thermosets also hold potential. It has been estimated that significant use of glass-reinforced polymers as structural components could yield a 20-35% reduction in vehicle weight. More importantly, the use of carbon fiber-reinforced materials could yield a 40-65% reduction in weight.

Das, S.

2001-01-26

465

Glue Polymer  

NSDL National Science Digital Library

What is a polymer, and what are some of its properties? This material is part of a series of hands-on science activities designed to arouse student interest. In this discovery activity students use white glue, water, and borax to make a vinyl polymer and study its properties. The activity includes a description, a list of science process skills and complex reasoning strategies being used, and a compilation of applicable K-12 national science education standards. Also provided are content topics, a list of necessary supplies, instructions, and presentation techniques. The content of the activity is explained, and assessment suggestions are provided.

Mid-continent Research for Education and Learning (McREL); Jacobs, Steve

2004-01-01

466

Nanomechanics of cellulose crystals and cellulose-based polymer composites  

NASA Astrophysics Data System (ADS)

Cellulose-polymer composites have potential applications in aerospace and transportation areas where lightweight materials with high mechanical properties are needed. In addition, these economical and biodegradable composites have been shown to be useful as polymer electrolytes, packaging structures, optoelectronic devices, and medical implants such as wound dressing and bone scaffolds. In spite of the above mentioned advantages and potential applications, due to the difficulties associated with synthesis and processing techniques, application of cellulose crystals (micro and nano sized) for preparation of new composite systems is limited. Cellulose is hydrophilic and polar as opposed to most of common thermoplastics, which are non-polar. This results in complications in addition of cellulose crystals to polymer matrices, and as a result in achieving sufficient dispersion levels, which directly affects the mechanical properties of the composites. As in other composite materials, the properties of cellulose-polymer composites depend on the volume fraction and the properties of individual phases (the reinforcement and the polymer matrix), the dispersion quality of the reinforcement through the matrix and the interaction between CNCs themselves and CNC and the matrix (interphase). In order to develop economical cellulose-polymer composites with superior qualities, the properties of individual cellulose crystals, as well as the effect of dispersion of reinforcements and the interphase on the properties of the final composites should be understood. In this research, the mechanical properties of CNC polymer composites were characterized at the macro and nano scales. A direct correlation was made between: - Dispersion quality and macro-mechanical properties - Nanomechanical properties at the surface and tensile properties - CNC diameter and interphase thickness. Lastly, individual CNCs from different sources were characterized and for the first time size-scale effect on their nanomechanical properties were reported. Then the effect of CNC surface modification on the mechanical properties was studied and correlated to the crystalline structure of these materials.

Pakzad, Anahita

467

Mathematical modeling of the in-mold coating process for injection-molded thermoplastic parts  

NASA Astrophysics Data System (ADS)

In-Mold Coating (IMC) has been successfully used for many years for exterior body panels made from compression molded Sheet Molding Compound (SMC). The coating material is a single component reactive fluid, designed to improve the surface quality of SMC moldings in terms of functional and cosmetic properties. When injected onto a cured SMC part, IMC cures and bonds to provide a pain-like surface. Because of its distinct advantages, IMC is being considered for application to injection molded thermoplastic parts. For a successful in mold coating operation, there are two key issues related to the flow of the coating. First, the injection nozzle should be located such that the thermoplastic substrate is totally covered and the potential for air trapping is minimized. The selected location should be cosmetically acceptable since it most likely will leave a mark on the coated surface. The nozzle location also needs to be accessible for easy of maintenance. Secondly, the hydraulic force generated by the coating injection pressure should not exceed the available clamping tonnage. If the clamping force is exceeded, coating leakage will occur. In this study, mathematical models for IMC flow on the compressible thermoplastic substrate have been developed. Finite Difference Method (FDM) is first used to solve the 1 dimensional (1D) IMC flow problem. In order to investigate the application of Control Volume based Finite Element Method (CV/FEM) to more complicated two dimensional IMC flow, that method is first evaluated by solving the 1D IMC flow problem. An analytical solution, which can be obtained when a linear relationship between the coating thickness and coating injection pressure is assumed, is used to verify the numerical results. The mathematical models for the 2 dimensional (2D) IMC flow are based on the generalized Hele-Shaw approximation. It has been found experimentally that the power law viscosity model adequately predicts the rheological behavior of the coating. The compressibility of the substrate is modeled by the 2-domain Tait PVT equation. CV/FEM is used to solve the discretized governing equations. A computer code has been developed to predict the fill pattern of the coating and the injection pressure. A number of experiments have been conducted to verify the numerical predictions of the computer code. It has been found both numerically and experimentally that the substrate thickness plays a significant role on the IMC fill pattern.

Chen, Xu

468

Polymer Blends  

Microsoft Academic Search

The concept of appropriately combining two or more different polymers to obtain a new material system with the desirable features of its constituents is not new. Over the years, numerous systems based on the chemical combination of different monomers through random, block, and graft copolymerization methods have been developed with this goal in mind. For similar reasons, the coatings and

D. R. Paul; J. W. Barlow

1980-01-01

469

Ferroelectric polymers  

Microsoft Academic Search

In the early 1970s it became clear that the polymer polyvinylidene fluoride is ferroelectric. There have been extensive studies of its properties and of the properties of copolymers of vinylidene fluoride with tri- or tetra-fluoroethylene. This work has led to a fairly complete understanding of the ferroelectric and related properties of these materials. The emphasis in this review is on

R. G. Kepler; R. A. Anderson

1992-01-01

470

Functional polymers  

SciTech Connect

Improving the existing polymer materials and the designing of model polymers need fundamental insights into the structure and dynamics over a large range of length and time scales. Consequently, a host of quite different methods needs to be applied to gain insights into the molecular and supramolecular structures and interactions that determine the performance of these materials. Supramolecular structures derived from shape persistent (stiff) macromolecules are used as examples to demonstrate the correlation between chemical structure, order phenomena and performance in applications concerning advanced or developing technologies: organic light emitting diodes (OLEDs) and separator membranes in lithium based batteries and fuel cells. Polymers are also important as additives in the manufacture and the processing of other materials. The design of block copolymers to control the nucleation and growth of inorganic particles precipitating from aqueous solutions (mineralization) is discussed as well as the use of block copolymers to optimize the processing of ceramic pieces and objects. Finally, the modification of surfaces by polymers including aspects of biocompatibility is discussed. Some remarks concerning the importance of recent developments and advances in synthesis of macromolecular materials are also given.

Wegner, G.

2000-01-01

471

Polymer solutions  

SciTech Connect

There is provided a method of making a polymer solution comprising polymerizing one or more monomer in a solvent, wherein said monomer comprises one or more ethylenically unsaturated monomer that is a multi-functional Michael donor, and wherein said solvent comprises 40% or more by weight, based on the weight of said solvent, one or more multi-functional Michael donor.

Krawczyk, Gerhard Erich (Bremen, DE); Miller, Kevin Michael (West Dundee, IL)

2011-07-26

472

High performance polyethylene/thermoplastic starch blends through controlled emulsification phenomena.  

PubMed

The emulsification efficacies of a range of compatibilizers for polyethylene/thermoplastic starch blends have been studied and a detailed morphological and mechanical analysis has been conducted. It is shown that polyethylene-maleic anhydride terpolymers containing elastomeric segments provided excellent emulsification of PE/TPS blends with a fine morphology (volume diameter of 1.4 ?m; number average diameter of 600 nm). The blends compatibilized with these copolymers exhibit a very high elongation at break of about 800%, the highest value ever reported for PE/TPS systems. Also, significant improvement in notched impact strength performance at interfacial saturation was found for these systems leading to specimens with an equivalent performance to pure polyethylene. An excellent correlation was found between the critical concentration for interfacial saturation and the mechanical properties, indicating the key role of morphology. PMID:23218276

Cerclé, Claire; Sarazin, Pierre; Favis, Basil D

2012-09-02

473

Study of structurally efficient graphite-thermoplastic trapezoidal-corrugation sandwich and semisandwich panels  

NASA Astrophysics Data System (ADS)

The structural efficiency of compression-loaded trapezoidal-corrugation sandwich and semisandwich composite panels is studied to determine their weight savings potential. Sandwich panels with two identical face sheets and a trapezoidal corrugated core between them, and semisandwich panels with a corrugation attached to a single skin are considered. An optimization code is used to find the minimum weight designs for critical compressive load levels ranging from 3000 to 24,000 lb/in. Graphite-thermoplastic panels based on the optimal minimum weight designs were fabricated and tested. A finite-element analysis of several test specimens was also conducted. The results of the optimization study, the finite element analysis, and the experiments are presented.

Jegley, Dawn C.

1994-03-01

474

Treatment of an intraoral bleeding in hemophilic patient with a thermoplastic palatal stent - A novel approach.  

PubMed

This is a case report of a 13-year old child diagnosed with hemophilia A. He reported with a bleeding wound in the middle part of the hard palate, due to trauma from a lead pencil. An intraoral palatal stent was planned to provide continuous pressure, stabilize the clot and allow local delivery of hemostatic agent. The stent was fabricated with a thermoplastic silicone rubber (biostar) under vacuum. The hemostatic agent used was one 500 mg capsule of tranxemic acid that was crushed and applied as a paste every 6 hourly. The patient was admitted under supervision for 3 days, where Recombinant factor VIII (rFVIII) intravenous infusion of 15-25 U/kg twice a day was given. Complete healing was observed in the traumatized area within 10 days. This article emphasizes on prenatal diagnosis, carrier screening and counseling of parents born with hemophilic children. PMID:22096778

Madan, Nidhi; Rathnam, Arun; Bajaj, Neeti

2011-01-01

475

Storage battery with thermoplastic casing having internal members for immobilizing the battery plates  

SciTech Connect

Downwardly extending members are molded on the inside of a synthetic resin battery case cover and bear against the bridging members of battery plate assemblies or upward bulges of the battery plates to hold the latter vertically in place. The downwardly extending thermoplastic members may be heat-softened at their ends at the time the cover is fused onto the rest of the battery case, or they may be made so that they will flex at that time or they may be made of two members that will telescope together against strong pressure, so that they will still bear against the electrode plates after the cover has been fused onto the rest of the casing.

Attinger, M.; Eisenacher, W.; Fraubose, F.; Makkens, L.; Niemann, G.

1980-09-09

476

Development of antimicrobial thermoplastic material from archaeal poly-?-L-glutamate and its nanofabrication.  

PubMed

Here we describe a stoichiometric ion-complex of archaeal poly-?-L-glutamate (L-PGA) and hexadecylpyridinium cation (HDP(+)), called PGAIC, which shows remarkable chemical resistance and potential as a novel functional thermoplastic. PGAIC films suppressed the proliferation of prokaryotic (Escherichia coli, Bacillus subtilis, Salmonella typhimurium, and Staphylococcus aureus) and eukaryotic (Saccharomyces cerevisiae) microorganisms. Moreover, its antifungal activity was demonstrated against a prevalent species of Candida (Candida albicans) and a filamentous fungus (Aspergillus niger). The minimal inhibitory concentrations were estimated as 0.25 mg mL(-1), and zones of growth inhibition appeared when PGAIC-coated polyethylene terephthalate (PET) films were placed in culture plates, whereas PET had very little effect on fungal growth. Soluble PGAIC thus shows promises as an antimicrobial and as a coating substrate. We also succeeded in synthesizing an L-PGA-based nanofiber using an ethanol solution of PGAIC. PMID:23388052

Ashiuchi, Makoto; Fukushima, Kenzo; Oya, Haruna; Hiraoki, Toshihumi; Shibatani, Shigeo; Oka, Nogiho; Nishimura, Hirokazu; Hakuba, Hirofumi; Nakamori, Masahiko; Kitagawa, Masaru

2013-02-19

477

Treatment of an intraoral bleeding in hemophilic patient with a thermoplastic palatal stent - A novel approach  

PubMed Central

This is a case report of a 13-year old child diagnosed with hemophilia A. He reported with a bleeding wound in the middle part of the hard palate, due to trauma from a lead pencil. An intraoral palatal stent was planned to provide continuous pressure, stabilize the clot and allow local delivery of hemostatic agent. The stent was fabricated with a thermoplastic silicone rubber (biostar) under vacuum. The hemostatic agent used was one 500 mg capsule of tranxemic acid that was crushed and applied as a paste every 6 hourly. The patient was admitted under supervision for 3 days, where Recombinant factor VIII (rFVIII) intravenous infusion of 15-25 U/kg twice a day was given. Complete healing was observed in the traumatized area within 10 days. This article emphasizes on prenatal diagnosis, carrier screening and counseling of parents born with hemophilic children.

Madan, Nidhi; Rathnam, Arun; Bajaj, Neeti

2011-01-01

478

Thermal Behaviour of Nanocomposites based on Glycerol Plasticized Thermoplastic Starch and Cellulose Nanocrystallites  

NASA Astrophysics Data System (ADS)

The objective of this study was to study the thermal behaviour of cellulose nanocrystals/TPS based nanocomposites. Nanocrystalline cellulose was isolated from cotton linters using sonochemical method and characterized through WAXRD & TEM. These nanocrystals were then dispersed in glycerol plasticized starch in varying proportions and films were cast. The thermal degradation of thermoplastic starch/cellulose nanocrystallite nanocomposites was studied using TGA under nitrogen atmosphere. Thermal degradation was carried out for nanocomposites at a rate of 10 °C/min and at different rates under nitrogen atmosphere namely 2, 5, 10, 20 and 40 °C/min for nanocomposites containing 10% cellulose nanocrystals. Ozawa and Flynn and Kissinger methods were used to determine the apparent activation energy of these nanocomposites. The addition of cellulose nanocrystallites produced a significant effect on the activation energy for thermal degradation of the composites materials in comparison with the matrix alone. These nanocomposites are potential applicant for food packaging applications.

Kaushik, Anupama; Kaur, Ramanpreet

2011-12-01

479

Thermoplastic deformation of silicon surfaces induced by ultrashort pulsed lasers in submelting conditions  

SciTech Connect

A hybrid theoretical model is presented to describe thermoplastic deformation effects on silicon surfaces induced by single and multiple ultrashort pulsed laser irradiation in submelting conditions. An approximation of the Boltzmann transport equation is adopted to describe the laser irradiation process. The evolution of the induced deformation field is described initially by adopting the differential equations of dynamic thermoelasticity while the onset of plastic yielding is described by the von Mises stress. Details of the resulting picometre sized crater, produced by irradiation with a single pulse, are discussed as a function of the imposed conditions and thresholds for the onset of plasticity are computed. Irradiation with multiple pulses leads to ripple formation of nanometre size that originates from the interference of the incident and a surface scattered wave. It is suggested that ultrafast laser induced surface modification in semiconductors is feasible in submelting conditions, and it may act as a precursor of the incubation effects observed at multiple pulse irradiation of materials surfaces.

Tsibidis, G. D. [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology (FORTH), N. Plastira 100, Vassilika Vouton, 70013, Heraklion, Crete (Greece); Stratakis, E. [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology (FORTH), N. Plastira 100, Vassilika Vouton, 70013, Heraklion, Crete (Greece); Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete (Greece); Aifantis, K. E. [Laboratory of Mechanics and Materials, Aristotle University of Thessaloniki, GR-54006 Thessaloniki (Greece)

2012-03-01

480

Thermoplastic fusion bonding using a pressure-assisted boiling point control system.  

PubMed

A novel thermoplastic fusion bonding method using a pressure-assisted boiling point (PABP) control system was developed to apply precise temperatures and pressures during bonding. Hot embossed polymethyl methacrylate (PMMA) components containing microchannels were sealed using the PABP system. Very low aspect ratio structures (AR = 1/100, 10 ?m in depth and 1000 ?m in width) were successfully sealed without collapse or deformation. The integrity and strength of the bonds on the sealed PMMA devices were evaluated using leakage and rupture tests; no leaks were detected and failure during the rupture tests occurred at pressures greater than 496 kPa. The PABP system was used to seal 3D shaped flexible PMMA devices successfully. PMID:22728966

Park, Taehyun; Song, In-Hyouk; Park, Daniel S; You, Byoung Hee; Murphy, Michael C

2012-06-22

481

Impact-damaged graphite-thermoplastic trapezoidal-corrugation sandwich and semi-sandwich panels  

NASA Astrophysics Data System (ADS)

The results of a study of the effects of impact damage on compression-loaded trapezoidal-corrugation sandwich and semi-sandwich graphite-thermoplastic panels are presented. Sandwich panels with two identical face sheets and a trapezoidal corrugated core between them, and semi-sandwich panels with a corrugation attached to a single skin are considered in this study. Panels were designed, fabricated and tested. The panels were made using the manufacturing process of thermoforming, a less-commonly used technique for fabricating composite parts. Experimental results for unimpacted control panels and panels subjected to impact damage prior to loading are presented. Little work can be found in the literature about these configurations of thermoformed panels.

Jegley, D.

482

Mechanical properties of long carbon fiber reinforced thermoplastic (LFT) at elevated temperature  

NASA Astrophysics Data System (ADS)

Long fiber reinforced thermoplastics (LFT) possess high specific modulus and strength, superior damage tolerance and fracture toughness and have found increasing use in transportation, military, and aerospace applications. However, one of the impediments to utilizing these materials is the lack of performance data in harsh conditions, especially at elevated temperature. In order to quantify the effect of temperature on the mechanical properties of carbon fiber reinforced thermoplastic composites, carbon fiber PAA composite plates containing 20% and 30% carbon fiber were produced using extrusion/compression molding process and tested at three representative temperatures, room temperature (RT 26°C), middle temperature (MID 60°C) and glass transition temperature (Tg 80°C). A heating chamber was designed and fabricated for the testing at elevated temperature. As temperature increases, flexural modulus, flexural strength, tensile modulus and tensile strength decrease. The highest reduction observed in stiffness (modulus) values of 30% CF/PAA at Tg in the 00 orientation is 75%. The reduction values were larger for the transverse (perpendicular to flow direction) samples than the longitudinal (flow direction) samples. The property reduction in 30% CF/PAA is larger than 20% CF/PAA. Furthermore, an innovative method was developed to calculate the fiber content in carbon fiber reinforced composites by burning off the neat resin and sample in a tube furnace. This method was proved to be accurate (within 1.5 wt. % deviation) by using burning off data obtained from CF/Epoxy and CF/Vinyl Ester samples. 20% and 30% carbon/PAA samples were burned off and carbon fiber content was obtained using this method. The results of the present study will be helpful in determining the end-user applications of these composite materials. Keywords: Long Carbon Fibers, Elevated Temperature, Mechanical Properties, Burn off Test.

Wang, Qiushi