Thematische Bibliographien / Polymers

Auswahl der wissenschaftlichen Literatur zum Thema „Polymers“

Autor: Grafiati
Veröffentlicht am 4. Juni 2021
Zuletzt aktualisiert am 22. Juni 2024

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Inhaltsverzeichnis

  1. Zeitschriftenartikel
  2. Dissertationen
  3. Bücher
  4. Buchteile
  5. Konferenzberichte
  6. Berichte der Organisationen

Zeitschriftenartikel zum Thema "Polymers":

1

Hili, Ryan, Chun Guo, Dehui Kong und Yi Lei. „Expanding the Chemical Diversity of DNA“. Synlett 29, Nr. 11 (20.03.2018): 1405–14. http://dx.doi.org/10.1055/s-0036-1591959.

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Nucleic acid polymers can be evolved to exhibit desired properties, including molecular recognition of a molecular target and catalysis of a specific reaction. These properties can be readily evolved despite the dearth of chemical diversity available to nucleic acid polymers, especially when compared to the rich chemical complexity of proteins. Expansion of nucleic acid chemical diversity has therefore been an important thrust for improving their properties for analytical and biomedical applications. Herein, we briefly describe the current state-of-the-art for the sequence-defined incorporation of modifications throughout an evolvable nucleic acid polymer. This includes contributions from our own lab, which have expanded the chemical diversity of nucleic acid polymers closer to the level observed in proteinogenic polymers.1 Introduction2 Polymerase-Catalyzed Synthesis of Modified Nucleic Acid ­Polymers3 Ligase-Catalyzed Oligonucleotide Polymerization (LOOPER)4 LOOPER with Small Modifications5 LOOPER with Large Modifications6 Evolution of Aptamers Derived from LOOPER Libraries7 Outlook
2

Chen, Guang, Lei Tao und Ying Li. „Predicting Polymers’ Glass Transition Temperature by a Chemical Language Processing Model“. Polymers 13, Nr. 11 (07.06.2021): 1898. http://dx.doi.org/10.3390/polym13111898.

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We propose a chemical language processing model to predict polymers’ glass transition temperature (Tg) through a polymer language (SMILES, Simplified Molecular Input Line Entry System) embedding and recurrent neural network. This model only receives the SMILES strings of a polymer’s repeat units as inputs and considers the SMILES strings as sequential data at the character level. Using this method, there is no need to calculate any additional molecular descriptors or fingerprints of polymers, and thereby, being very computationally efficient. More importantly, it avoids the difficulties to generate molecular descriptors for repeat units containing polymerization point ‘*’. Results show that the trained model demonstrates reasonable prediction performance on unseen polymer’s Tg. Besides, this model is further applied for high-throughput screening on an unlabeled polymer database to identify high-temperature polymers that are desired for applications in extreme environments. Our work demonstrates that the SMILES strings of polymer repeat units can be used as an effective feature representation to develop a chemical language processing model for predictions of polymer Tg. The framework of this model is general and can be used to construct structure–property relationships for other polymer properties.
3

Brostow, Witold, Hanna Fałtynowicz, Osman Gencel, Andrei Grigoriev, Haley E. Hagg Lobland und Danny Zhang. „Mechanical and Tribological Properties of Polymers and Polymer-Based Composites“. Chemistry & Chemical Technology 14, Nr. 4 (15.12.2020): 514–20. http://dx.doi.org/10.23939/chcht14.04.514.

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A definition of rigidity of polymers and polymer-based composites (PBCs) by an equation is formulated. We also discuss tribological properties of polymers and PBCs including frictions (static, sliding and rolling) and wear. We discuss connections between viscoelastic recovery in scratch resistance testing with brittleness B, as well as Charpy and Izod impact strengths relations with B. Flexibility Y is related to a dynamic friction. A thermophysical property, namely linear thermal expansivity, is also related to the brittleness B. A discussion of equipment needed to measure a variety of properties is included.
4

Chen, Jian Fang, und Ai Hua Ling. „Design and Synthesis of a Miktoarm Star PMMAZO-(PCL)2 Copolymer“. Advanced Materials Research 332-334 (September 2011): 2089–92. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.2089.

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A series of novel miktoarm star polymers were synthesized by combination of at-om transfer radical polymerization(ATRP), chemical modification and ring-opening polymeri-zation(ROP). These miktoarm star polymers carring one poly[6-(4-methoxy-4’-oxy-azobenzene) hexylmethacrylate] azobenzene (PMMAZO) side-chain liquid crystalline(LC) arm and two polycaprolactone(PCL) arms. These precursors and miktoarm star polymers were characterized by proton nuclear resonance (1H-NMR), and gel permeation chramatograph(GPC). The information of PMMAZO(OH)2 and PMMAZO-(PCL)2 miktoarm star polymer confirmed the expected structure.
5

Shahzadi, Maria, Taimoor Hassan und Sana Saeed. „Application of Natural Polymers in Wound Dressings“. Pakistan Journal of Medical and Health Sciences 16, Nr. 10 (30.10.2022): 1–2. http://dx.doi.org/10.53350/pjmhs2216101.

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Natural polymers because of their biodegradability, biocompatibility and closeness to the extracellular matrix are frequently used in regenerative medicine for burns and wound dressing. By triggering and stimulating the wound healing process, natural polymers aid in the restoration of damaged tissues and, as a result, skin regeneration1. Natural polymers have proven to be effective in a variety of biomedical applications, such as controlled administration of drugs, gene delivery, and regenerative medicine, among others.Plants, animals, and microbial are the major sources responsible for production of natural polymers. Based on their chemistry natural polymers are divided into polysaccharide, protein, polyester, and polyamide-based polymers2. Because of their 3 D cross-link-based networks of polymer, immersed with water or other biological fluids, hydrogels are considered worthwhile in the Biomedical and pharmaceutical industries for wound care, burn dressing, medication administration, tissue engineering and transplantation of organs3. Natural polymers used in wound dressings: Here are several natural polymers which are effectively used in wound management.
6

Martens, C. M., R. Tuinier und M. Vis. „Depletion interaction mediated by semiflexible polymers“. Journal of Chemical Physics 157, Nr. 15 (21.10.2022): 154102. http://dx.doi.org/10.1063/5.0112015.

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We present a simple mean-field theory to describe the polymer-mediated depletion attraction between colloidal particles that accounts for the polymer’s chain stiffness. We find that for fixed polymer radius of gyration and volume fraction, the strength of this attraction increases with increasing chain stiffness in both dilute and semidilute concentration regimes. In contrast, the range of attraction monotonically decreases with chain stiffness in the dilute regime, while it attains a maximum in the semidilute regime. The obtained analytical expressions for the depletion interaction were compared with numerical self-consistent field lattice computations and shown to be in quantitative agreement. From the interaction potential between two spheres, we calculated the second osmotic virial coefficient B2, which appears to be a convex function of chain stiffness. A minimum of B2 as a function of chain stiffness was observed both in the numerical self-consistent field computations and the analytical theory. These findings help explain the general observation that semiflexible polymers are more effective depletants than flexible polymers and give insight into the phase behavior of mixtures containing spherical colloids and semiflexible polymers.
7

Caldona, Eugene B., Ernesto I. Borrego, Ketki E. Shelar, Karl M. Mukeba und Dennis W. Smith. „Ring-Forming Polymerization toward Perfluorocyclobutyl and Ortho-Diynylarene-Derived Materials: From Synthesis to Practical Applications“. Materials 14, Nr. 6 (18.03.2021): 1486. http://dx.doi.org/10.3390/ma14061486.

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Many desirable characteristics of polymers arise from the method of polymerization and structural features of their repeat units, which typically are responsible for the polymer’s performance at the cost of processability. While linear alternatives are popular, polymers composed of cyclic repeat units across their backbones have generally been shown to exhibit higher optical transparency, lower water absorption, and higher glass transition temperatures. These specifically include polymers built with either substituted alicyclic structures or aromatic rings, or both. In this review article, we highlight two useful ring-forming polymer groups, perfluorocyclobutyl (PFCB) aryl ether polymers and ortho-diynylarene- (ODA) based thermosets, both demonstrating outstanding thermal stability, chemical resistance, mechanical integrity, and improved processability. Different synthetic routes (with emphasis on ring-forming polymerization) and properties for these polymers are discussed, followed by their relevant applications in a wide range of aspects.
8

Ewert, Ernest, Izabela Pospieszna-Markiewicz, Martyna Szymańska, Adrianna Kurkiewicz, Agnieszka Belter, Maciej Kubicki, Violetta Patroniak, Marta A. Fik-Jaskółka und Giovanni N. Roviello. „New N4-Donor Ligands as Supramolecular Guests for DNA and RNA: Synthesis, Structural Characterization, In Silico, Spectrophotometric and Antimicrobial Studies“. Molecules 28, Nr. 1 (03.01.2023): 400. http://dx.doi.org/10.3390/molecules28010400.

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The present work reports the synthesis of new N4-donor compounds carrying p-xylyl spacers in their structure. Different Schiff base aliphatic N-donors were obtained synthetically and subsequently evaluated for their ability to interact with two models of nucleic acids: calf-thymus DNA (CT-DNA) and the RNA from yeast Saccharomyces cerevisiae (herein simply indicated as RNA). In more detail, by condensing p-xylylenediamine and a series of aldehydes, we obtained the following Schiff base ligands: 2-thiazolecarboxaldehyde (L1), pyridine-2-carboxaldehyde (L2), 5-methylisoxazole-3-carboxaldehyde (L3), 1-methyl-2-imidazolecarboxaldehyde (L4), and quinoline-2-carboxaldehyde (L5). The structural characterisation of the ligands L1-L5 (X-ray, 1H NMR, 13C NMR, elemental analysis) and of the coordination polymers {[CuL1]PF6}n (herein referred to as Polymer1) and {[AgL1]BF4}n, (herein referred to as Polymer2, X-ray, 1H NMR, ESI-MS) is herein described in detail. The single crystal X-ray structures of complexes Polymer1 and Polymer2 were also investigated, leading to the description of one-dimensional coordination polymers. The spectroscopic and in silico evaluation of the most promising compounds as DNA and RNA binders, as well as the study of the influence of the 1D supramolecular polymers Polymer1 and Polymer2 on the proliferation of Escherichia coli bacteria, were performed in view of their nucleic acid-modulating and antimicrobial applications. Spectroscopic measurements (UV–Vis) combined with molecular docking calculations suggest that the thiazolecarboxaldehyde derivative L1 is able to bind CT-DNA with a mechanism different from intercalation involving the thiazole ring in the molecular recognition and shows a binding affinity with DNA higher than RNA. Finally, Polymer2 was shown to slow down the proliferation of bacteria much more effectively than the free Ag(I) salt.
9

Becskereki, Gergely, George Horvai und Blanka Tóth. „The Selectivity of Molecularly Imprinted Polymers“. Polymers 13, Nr. 11 (28.05.2021): 1781. http://dx.doi.org/10.3390/polym13111781.

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The general claim about novel molecularly imprinted polymers is that they are selective for their template or for another target compound. This claim is usually proved by some kind of experiment, in which a performance parameter of the imprinted polymer is shown to be better towards its template than towards interferents. A closer look at such experiments shows, however, that different experiments may differ substantially in what they tell about the same imprinted polymer’s selectivity. Following a short general discussion of selectivity concepts, the selectivity of imprinted polymers is analyzed in batch adsorption, binding assays, chromatography, solid phase extraction, sensors, membranes, and catalysts. A number of examples show the problems arising with each type of application. Suggestions for practical method design are provided.
10

Chang, L. L., D. L. Raudenbush und S. K. Dentel. „Aerobic and anaerobic biodegradability of a flocculant polymer“. Water Science and Technology 44, Nr. 2-3 (01.07.2001): 461–68. http://dx.doi.org/10.2166/wst.2001.0802.

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Flocculant polymers are used to improve the efficiency of separation processes used in wastewater treatment. The subsequent fate and effects of these additives are uncertain, however, with some previous reports indicating them to be biodegradable while others indicate complete recalcitrance. The biodegradability of a common flocculant polymer was therefore evaluated, using both aerobic and anaerobic batch assays. Knowledge of the polymer's chemical composition also allowed degradation stoichiometries to be calculated for complete biodegradation and also for incomplete degradation to several hypothesized end products. Results showed conclusively that the polymer was subject to partial degradation by both aerobic and anaerobic cultures. Measured oxygen consumption under aerobic conditions, and gas production under anaerobic conditions, both indicate that the partial destruction of pendant cationic moieties occurs, but that the polymer's CH2 backbone remains essentially intact. These results allow seemingly contradictory previous reports to be explained. The findings are relevant to the environmental fate of these polymers as well as certain treatment process effects.
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Zeitschriftenartikel Dissertationen Bücher

Dissertationen zum Thema "Polymers":

1

Schlindwein, Walkiria Santos. „Conducting polymers and polymer electrolytes“. Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/33889.

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Polymers are mostly used as insulator materials. Since the late sixties, two new classes of polymeric materials possessing either ionic or electronic conductivities have been extensively studied. The work carried out in this thesis concerns of the study of polymer electrolytes based on poly(ethylene oxide) (PEO) complexed with divalent salts (ionic conductors) and polypyrroles (PPy) electrochemically and chemically prepared (electronic conductors). Different techniques were used to study their properties including Differential Scanning Calorimetry (DSC), Variable Temperature Polarising Microscopy (VTPM), Extended X-ray Absorption Fine Structure (EXAFS), a.c. Impedance, Cyclic Voltammetry, and Fourier Transform Infra-Red Spectroscopy (FTIR). Water-cast films of PEOn:ZnX2 (X = C1, Br, I) were prepared at a range of stoichiometries. The effects of either residual presence of water or thermal treatment related to the formation of high melting crystalline materials were investigated. The morphology of the zinc halides films differs from similar films cast from acetonitrile/methanol mixtures. The presence of high melting crystalline material in the water cast samples is influenced mostly by the concentration, type of anion and drying procedure applied to the samples. The high melting crystalline materials in the zinc samples are more affected by the drying regime. In some cases, solvent effects can be removed by using a high temperature (e.g. 180°C) drying regime. The presence of water normally depresses the melting temperature of the crystalline structures. Films of PEOn.:CaBr2 and PEOn:NiBr2 cast from water were also examined. The high melting crystalline materials in the calcium samples are more affected by the presence of water. The nickel samples are highly crystalline and the presence of high melting material does not seem to be influenced by either the presence of solvent or the drying procedure. EXAFS was used as a suitable technique to probe the local structure surrounding the cation. The results of the zinc halide samples gave some indication of the interionic and polymer-cation interactions. It was demonstrated that the halogen provides the most substantial contribution for the total EXAFS spectrum and the oxygen contribution is much less significant, except in the case of PEOn:ZnC12 samples. This could be due to the size of the nearest neighbour atoms and/or to the interaction polymer-cation. The presence of neutral "ion pairing" is suggested for the PEOn:ZnBr2 samples. The EXAFS results for the samples containing NiBr2 indicated a strong interaction between polymer-salt and the local structure was dependent on concentration, unlike the zinc samples. The polymerisation of pyrrole was investigated by using chemical and electrochemical oxidation routes. The structural characterisation of the compounds obtained was limited by their insolubility. The electrochemically prepared samples presented higher conductivity than the ones which were chemically prepared. The EXAFS results at the Fe K-edge of the PPyFeCl4 sample, which was prepared by direct chemical oxidation, suggested that the iron is coordinated to oxygens at a distance 1.97 A, chlorines at 3.08 A and perhaps nitrogens at 3.72 A. The iron local structure of the composite PVA/PPy doped with FeCl3 was different from the PPyFeCl4 sample. The iron in the composite sample was coordinated to oxygens at 1.98 A and chlorines at 2.18 A. Alternatively, the presence of a distorted FeCl4- is considered.
2

Muangpil, Sairoong. „Functionalised polymers and nanoparticle/polymer blends“. Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654111.

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The incorporation of nanoparticles into polydimethylsiloxane polymers either in the form of physical blending or chemical crosslinking has long been studied as it can improve the properties of composite materials. Interactions between the host polymer and the filler particle, filler concentration and conformation of each component are the key factors that influence these properties. Understanding the effect of these factors is of fundamental importance in all practical applications of composite materials. This thesis describes the study of a range of PDMS composites by using a variety of experimental techniques. The main techniques used were spin-spin (T2) relaxation and diffusion NMR spectroscopy, rheology and small-angle neutron scattering (SANS). The molecular mobility of a series of PDMS melts has been studied for both unentangled and entangled molecular weight regimes separated by the critical entanglement molecular weight (Mc) of the polymer. The experimental results revealed the effect of molecular weight and polydispersity of the polymers on their segmental mobility. The dramatic decrease of chain mobility observed at molecular weight above Mc was attributed to the effect of chain entanglements. The effect of nano-sized trimethylsilylated polysilicate resin (R2) on the chain mobility of PDMS in the form of physically blended was also examined. Two different concentrations (17 and 30 vol%) of R2 were incorporated into a wide range molecular weight of PDMS melts. Below Mc, the R2 particle was found to reinforce the PDMS at all particle loadings, whereas a plasticisation effect was observed for high molecular weight PDMS above Mc. This was attributed to a reduction of the degree of the entanglements when polymer chains adsorbed on particles. Chemically bonded composites of PDMS and polyhedral oligomeric silsesquioxane (POSS) were successfully synthesised via hydrosilylation. The length of the PDMS central block was found to affect both the size and the molecular mobility of the triblock polymers. The weight fraction of POSS and substituted groups on POSS were also seen to affect the molecular mobility. Finally, a series ofrandom crosslink polymer films ofPDMS and phenylsilsesquioxane (TPh) was studied by AFM, TEM, SAXS and SANS techniques to investigate the factors influencing the optical clarity of the samples. The degree of swelling and the segmental mobility of the sample films swollen in good and poor solvents were also studied.
3

Chester, Shawn Alexander. „Mechanics of amorphous polymers and polymer gels“. Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68898.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 345-356).
Many applications of amorphous polymers require a thermo-mechanically coupled large-deformation elasto-viscoplasticity theory which models the strain rate and temperature dependent response of amorphous polymeric materials in a temperature range which spans the glass transition temperature of the material. We have formulated such a theory, and also numerically implemented our theory in a finite element program. The material parameters in the theory have been calibrated for poly(methyl methacrylate), polycarbonate, and Zeonex - a cyclo-olefin polymer. The predictive capabilities of the constitutive theory and its numerical implementation have been validated by comparing the results from a suite of validation experiments against corresponding results from numerical simulations. Amorphous chemically-crosslinked polymers form a relatively new class of thermallyactuated shape-memory polymers. Several biomedical applications for thermally-actuated shape-memory polymers have been proposed/demonstrated in the recent literature. However, actual use of such polymers and devices made from these materials is still quite limited. For the variety of proposed applications to be realized with some confidence in their performance, it is important to develop a constitutive theory for the thermo-mechanical response of these materials and a numerical simulation-based design capability which, when supported with experimental data, will allow for the prediction of the response of devices made from these materials under service conditions. We have developed such a theory and a numerical simulation capability, and demonstrated its utility for modeling the thermo-mechanical response of the shape-memory polymer tBA-PEGDMA. An elastomeric gel is a cross-linked polymer network swollen with a solvent, and certain thermally-responsive gels can undergo large reversible volume changes as they are cycled about a critical temperature. We have developed a thermodynamically-consistent continuum-level theory to describe the coupled mechanical-deformation, fluid permeation, and heat transfer of such gels. We have numerically implemented our theory in a finite element program by writing thermo-chemo-mechanically coupled elements. We show that our theory is capable of simulating swelling, squeezing of fluid by applied mechanical forces, and thermally-responsive swelling/de-swelling of such materials.
by Shawn Alexander Chester.
Ph.D.
4

Mohagheghian, Iman. „Impact response of polymers and polymer nanocomposites“. Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648854.

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5

Sun, Shuangyi. „Alkoxyphenacyl Polymers: A Novel Photodegradable Polymer Platform“. University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1424234383.

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6

Michal, Brian. „Multi-Functional Stimuli-Responsive Polymers“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459440396.

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Smartt, William Mark. „Formation of microporous polymer via thermally-induced phase transformations in polymer solutions“. Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/32853.

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Amalou, Zhor. „Contribution à l'étude de la structure semi-cristalline des polymères à chaînes semi-rigides“. Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210832.

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Les polymères semi-cristallins à chaînes semi-rigides, bien qu’abondamment utilisés dans la vie quotidienne, représentent des systèmes complexes qui ne sont pas encore parfaitement compris. Parmi les nombreux domaines de recherche sur cette famille de polymères, l’étude de la morphologie semi-cristalline et des processus de cristallisation et de fusion de ceux-ci restent des sujets très importants. L’investigation de la morphologie semi-cristalline est rendue difficile car elle présente une structure hiérarchique composée de plusieurs niveaux d’organisation, dont le plus petit est observable à une échelle très réduite de quelques nanomètres. De plus, les aspects liés à la cinétique des processus de cristallisation et de fusion n’ont pas toujours permis de bien les mettre en évidences, les rendant ainsi par très bien compris. Cependant, les nouvelles avancées technologiques dans le domaine de la physique expérimentales ont beaucoup profité à la science des polymères.

Dans ce travail, une contribution originale est apportée à cette étude, et cela en combinant diverses techniques expérimentales permettant des mesures calorifiques et structurales en températures et temps réels. L’intérêt c’est porté sur les polymères linéaires aromatiques tels que le polyéthylènes teréphthalate, PET, et le polytriméthylène téréphthalate, PTT, caractérisés par une température de transition vitreuse supérieure à l’ambiante ( Tg > 50°) et une température de fusion élevée (Tm>220°C), offrant ainsi une assez large gamme de température de cristallisation (Tm-Tg). L’étude de la structure semi-cristalline du PET à l’échelle du nanomètre et de la relaxation des phases amorphes présentes dans sa structure est facilitée par l’utilisation d’un diluant amorphe tel que le polyétherimide (PEI), qui forme un mélange miscible avec le PET.

L’utilisation de microscopie de force atomique AFM à haute température a permis d’observer la cristallisation isotherme de PET en temps réel et de décrire ainsi la cristallisation secondaire comme un processus d'épaississement des piles lamellaires. De plus, l’analyse de la structure semi-cristalline du PET et du PTT, dans l’espace direct, sont en faveur d’un modèle structural homogène, où l’épaisseur lamellaire moyenne est légèrement inférieure à l’épaisseur moyenne des régions amorphes interlamellaires. Ces résultats ont permis, d’une part, d’apporter une meilleure interprétation aux données obtenues par diffusion des rayons X aux petits angles (SAXS), et d’autre part, d’ interpréter le comportement de fusion multiple caractéristique des polymères semi-cristallin à chaînes semi-rigides par le seul processus de fusion-recristallisation. Dans l’étude investiguée sur les mélanges PET/PEI et sur le PTT pur, on montre que la cinétique d’un tel processus est particulièrement rapide comparée à la cristallisation. De plus, les observations par AFM et par microscopie optique de même que les mesures SAXS en temps réel ont montré la simultanéité et la compétition existant entre la fusion des cristaux et leur réorganisation durant la chauffe. Par ailleurs, la relaxation des régions amorphes interlamellaires, souvent considérées comme rigides, a pu être mise en évidence par les mesures AFM et SAXS réalisées à haute température sur des échantillons de PET/PEI semi-cristallins.


Doctorat en sciences, Spécialisation physique
info:eu-repo/semantics/nonPublished

9

Cooke, Richard Hunter III. „THE ENHANCEMENT OF PEROXIDE-CURED FLUOROELASTOMER RUBBER TO METAL BONDING“. Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1377022145.

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10

Yang, Lianyun. „Novel Ferroelectric Behavior in Poly(vinylidene fluoride-co-trifluoroethylene)-Based Random Copolymers“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1431686125.

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Bücher zum Thema "Polymers":

1

Mark, James E. Inorganic polymers. Englewood Cliffs, N.J: Prentice Hall, 1992.

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2

Mark, James E. Inorganic polymers. 2. Aufl. New York: Oxford University Press, 2005.

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3

Powell, Peter C. Engineering with polymers. 2. Aufl. Cheltenham: Stanley Thornes, 1998.

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4

Ulrich, Henri. Introduction to industrial polymers. 2. Aufl. Munich: Hanser Publishers, 1993.

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5

Godovsky, Yu K., K. Horie, A. Kaneda, N. Kinjo, L. F. Kosyanchuk, Yu S. Lipatov, T. E. Lipatova et al. Speciality Polymers/Polymer Physics. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/bfb0017962.

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6

Akelah, A. Functionalized polymers and their applications. London: Chapman and Hall, 1990.

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7

Rubinson, Judith F., und Harry B. Mark, Hrsg. Conducting Polymers and Polymer Electrolytes. Washington, DC: American Chemical Society, 2002. http://dx.doi.org/10.1021/bk-2003-0832.

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8

Chiellini, Emo, Junzo Sunamoto, Claudio Migliaresi, Raphael M. Ottenbrite und Daniel Cohn, Hrsg. Biomedical Polymers and Polymer Therapeutics. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/b112950.

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I, Kroschwitz Jacqueline, Hrsg. Polymers: Polymer characterization and analysis. New York: Wiley, 1990.

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Emo, Chiellini, und International Symposium on Frontiers in Biomedical Polymers including Polymer Therapeutics: From Laboratory to Clinical Practice (3rd : 1999 : Shiga, Japan), Hrsg. Biomedical polymers and polymer therapeutics. New York: Kluwer Academic/Plenum Publishers, 2001.

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Buchteile zum Thema "Polymers":

1

Xanthos, Marino. „Polymers and Polymer Composites“. In Functional Fillers for Plastics, 1–16. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527605096.ch1.

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Xanthos, Marino. „Polymers and Polymer Composites“. In Functional Fillers for Plastics, 1–18. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527629848.ch1.

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Parisi, Ortensia Ilaria, Manuela Curcio und Francesco Puoci. „Polymer Chemistry and Synthetic Polymers“. In Advanced Polymers in Medicine, 1–31. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-12478-0_1.

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Bhatia, Saurabh. „Natural Polymers vs Synthetic Polymer“. In Natural Polymer Drug Delivery Systems, 95–118. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-41129-3_3.

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Brandrup, Johannes, und Wiesbaden. „Polymers, Polymer Recycling, and Sustainability“. In Plastics and the Environment, 521–62. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2004. http://dx.doi.org/10.1002/0471721557.ch13.

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Hagnauer, Gary L. „Polymers and Polymer Precursor Characterization“. In Materials Characterization for Systems Performance and Reliability, 189–243. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2119-4_9.

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Walton, David J., und J. Phillip Lorimer. „General principles and historical aspects“. In Polymers. Oxford University Press, 2000. http://dx.doi.org/10.1093/hesc/9780198503897.003.0001.

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This chapter provides an overview of polymers, which are formed by linking large numbers of small molecules together. Polymers are now ubiquitous in daily life. Not only have polymers found a wide use in structural and textile materials, polymer substitutes have also found a wide application in medicine. Moreover, synthetic polymers have had a sizeable impact in the field of fibres, plastics, and rubbers (elastomers). While the majority of polymers are synthetic polymers, there are natural polymers such as proteins, natural rubber, and cellulose, each of which could be fitted into a similar category. It was as a result of early attempts to modify these natural materials that the important understanding of polymer behaviour arose. The chapter then presents the general principles of polymerization; the statistical nature of polymer chains; and the general principles of industrial polymer synthesis.
8

Han, Chang Dae. „Rheology of Particulate-Filled Polymers, Nanocomposites, and Fiber-Reinforced Thermoplastic Composites“. In Rheology and Processing of Polymeric Materials: Volume 1: Polymer Rheology. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195187823.003.0018.

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Polymer composites consisting of a thermoplastic polymer forming the matrix phase and a large amount of inorganic particles (commonly referred to as fillers) or glass fibers, which are often referred to as particulate-filled polymers, are very common in the plastics and elastomer’s industries (Deanin and Schott 1974; Kraus 1965; Lubin 1969). Polymer composites are developed to achieve a set of properties not possessed by the thermoplastic polymer (i.e., polymeric matrix) alone. Polymeric matrices can be thermoplastics, which soften and behave as viscous liquids when heated to above their glass transition temperatures (in the case of amorphous thermoplastic polymers) or above their melting temperatures (in the case of semicrystalline thermoplastic polymers). Polymeric matrices can also be thermosets, which undergo a transformation from a viscous resinous liquid to a hard or rubbery solid in the presence of heat and/or curing agents. There are numerous industrial products made of particulate-filled polymeric materials; for example, thermoplastic polymers filled with mica or calcium carbonate, carbon-black-filled elastomers, thermoplastic polymers or thermosets reinforced with glass fibers or carbon fibers. The ultimate goal of adding fillers to a thermoplastic polymer and adding glass fiber or carbon fiber to a thermoset is to improve the mechanical properties of the polymer. However, fillers, glass fibers, or carbon fibers themselves usually supply little or no reinforcement since there is little interfacial interaction between a thermoplastic polymer and fillers, and between a thermoset and glass fiber or carbon fiber. This has led to the development of “coupling agents,” chemical additives capable of improving the interfacial bonds between a thermoplastic polymer and fillers, and between a thermoset and glass fibers or carbon fibers (Plueddemann 1982). The use of coupling agents for the surface modification of fillers to reinforce thermoplastics has generally been directed towards improving the mechanical strength and chemical resistance of composites by improving adhesion across the interface. When inorganic fillers or glass fibers are added to a thermoplastic polymer, the resulting material exhibits a complex rheological behavior, quite different from the rheology of neat homopolymers presented in Chapter 6.
9

Han, Chang Dae. „Relationships Between Polymer Rheology and Polymer Processing“. In Rheology and Processing of Polymeric Materials: Volume 1: Polymer Rheology. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195187823.003.0005.

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Polymer products have long been used for a variety of applications in our daily lives, as well as for some more exotic applications, such as biomedical devices, superhigh- speed airplanes, and outer-space vehicles. Other applications are too numerous to mention them all here. There are many steps involved in the production of polymer products, from the synthesis of raw materials to the manufacturing of the finished products. Of the many steps involved, the fabrication (processing) step plays a pivotal role in determining the quality of the final products. Successful processing of polymeric materials requires a good understanding of their rheological behavior (Han 1976, 1981). Thus, intimate relationships exist between polymer rheology and polymer processing. In this chapter we describe briefly some of these close relationships between polymer rheology and polymer processing. Rheology is the science that deals with the deformation and flow of matter. Hence, polymer rheology is the science that deals with the deformation and flow of polymeric materials. Since there are a variety of polymeric materials, we can classify polymer rheology further into different categories, depending upon the nature of the polymeric materials; for instance, (1) the rheology of homogeneous polymers, (2) the rheology of miscible polymer blends, (3) the rheology of immiscible polymer blends, (4) the rheology of particulate-filled polymers, (5) the rheology of fiberglass-reinforced polymers, (6) the rheology of organoclay nanocomposites, (7) the rheology of polymeric foams, (8) the rheology of thermosets, (9) the rheology of block copolymers, and (10) the rheology of liquid-crystalline polymers. Each of these polymeric materials exhibits its own unique rheological characteristics. Thus, different theories are needed to interpret the experimental results of the rheological behavior of different polymeric materials. However, at present we do not have a comprehensive theory that can describe the rheological behavior of some polymeric materials and thus we must resort to empirical correlations to interpret the experimentally observed rheological behavior of those materials. It is then fair to state that a complete understanding of the rheological behavior of all polymeric materials remains quite a challenge indeed.
10

Sachdeva, Amit, und Pramod K. Singh. „Reliability Study of Polymers“. In AI Techniques for Reliability Prediction for Electronic Components, 45–54. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1464-1.ch002.

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The chapter deals with brief introduction to polymers, composites, and nanocomposites along with their reliability. When we talk about polymeric composites, the terms crystallinity and amorphicity play a very important role, and both of these properties are highly affected by variation in temperature condition. On increasing temperature, the crystalline domains of polymers tend to become amorphous, and as we reduce the temperature, crystalline domains tend to increase. So the reliability of a particular polymer is widely dependent on temperature conditions.

Konferenzberichte zum Thema "Polymers":

1

Liu, Y. S., H. S. Cole und H. R. Philipp. „Interactions of excimer lasers with polymers“. In International Laser Science Conference. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/ils.1986.fb2.

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Interaction of high photon energy (> 5-eV) radiation from excimer lasers with polymeric materials has drawn much interest because of its potential importance in material processing such as etching and patterning which have found use over a number of diversified fields such as medicine, polymer science, and microelectronics. The laser etching process is noncontact, maskless, selective, and offers a high spatial resolution. Although the topic has been the subject of numerous recent studies, basic parameters for understanding interactions between polymers and high energy photons are not well understood. In this paper we present the results of a recent study on VUV optical properties of several polymeric materials including polymethyl methacrylate (PMMA), polystyrene (PS), polyvinylacetate (PVA), polyimide (PI), and polycarbonate (PC) and review parameters that are critical for understanding the interaction of polymers with excimer laser radiation. Results of a study of the surface compostions using small area x-ray photoelectron spectroscopy of two kinds of polymer, PMMA and PS, irradiated with an ArF laser at a photon energy of 6.4 eV are discussed. A simple model is then presented to show how various parameters including optical constants, photon energy, laser fluence, and polymer structures affect characteristics of photon etching observed in these polymers.
2

Zhang, Yadong, Liming Wang, Tatsuo Wada und Hiroyuki Sasabe. „Carbazole Main-Chain Polymers with Di-Acceptor-Substituents for Nonlinear Optics“. In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/otfa.1993.wd.8.

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Polymeric second-order nonlinear optical (NLO) materials have been studied extensively in recent years for applications in electrooptic devices [1,2]. There are three types of polymer materials developed for this purpose: guest-host systems [3], side-chain polymers [4-6], and main-chain polymers [7-9]. The second-order NLO effects of these materials were demonstrated after electric poling above the polymer glass transition temperature (Tg). While many guest-host and side-chain NLO polymers have been developed, relatively few main-chain polymers have been prepared. Most of the main-chain polymers reported are heat-to tail; namely, all the Chromophore dipole moments point in the same direction along the polymer main chain.
3

Inganas, Olle, Soumyadeb Ghosh, Emil J. Samuelsen, Knut E. Aasmundtveit, Leif A. A. Pettersson und Tomas Johansson. „Model polymers for polymer actuators“. In 1999 Symposium on Smart Structures and Materials, herausgegeben von Yoseph Bar-Cohen. SPIE, 1999. http://dx.doi.org/10.1117/12.349712.

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4

Burland, D. M., R. G. Devoe, M. C. Jurich, V. Y. Lee, R. D. Miller, C. R. Moylan, J. I. Thackara, R. J. Twieg, T. Verbiest und W. Volksen. „Incorporation of Thermally Stable Nonlinear Optical Polymers into Electrooptic Devices“. In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/otfa.1995.wa.3.

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In order to be useful in practical nonlinear optical(NLO) devices such as high speed optical switches and modulators, several key properties of electrooptic(EO) polymers must be optimized: the polymer's electrooptic response must be sufficiently large, the response must be stable at all temperatures that the polymer will experience in processing and in operation and the attenuation of light in the polymer by scattering and by absorption must be low. For the specific applications of on-chip and chip-to-chip active optical interconnects, the thermal stability requirements are particularly severe. During the processes of microprocessor die attachment and hermetic packaging, the EO polymer will experience temperatures of >300°C for several minutes[1]. We have investigated the potential and limitations of electrooptic polymers under these severe thermal conditions, proceeding from the identification of NLO chromophores with high intrinsic molecular hyperpolarizabilities[2], incorporation into thermally stable polymers[3][4], and fabrication into electrooptic switches and devices[5].
5

Kippelen, B., K. Meerholz, B. L. Volodin, Sandalphon und N. Peyghambarian. „High Efficiency Photorefractive Polymers“. In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/otfa.1995.wgg.2.

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The processibility and structural flexibility of photorefractive polymers give them an important technological potential and have driven intensive research efforts to improve the performance of this new class of PR materials. Since the first proof of principle of photorefractivity in a polymer [1], numerous PR polymeric materials have been synthesized by using different approaches [2], but significant performance improvement was obtained by using the photoconductive polymer poly(N-vinylcarbazole) (PVK) as the composite host and by doping it with nonlinear optical molecules referred to as chromophores [3,4]. In plasticized PVK-based polymer composites doped with the chromophore 2,5-dimethyl-4-(p-nitrophenylazo)anisole) (DMNPAA) [4], we recently demonstrated [5] that PR polymeric materials can exhibit light-induced refractive index modulation amplitudes as high as Δn = 7 × 10-3 at 1 W/cm2 writing intensity, and applied field of 90 V/µm. As shown in Fig. 1, such a high index modulation leads to complete diffraction and periodic energy transfer between the probe and diffracted beams in four-wave mixing (FWM) experiments and also, to net gain coefficients in excess of 200 cm-1 in two-beam coupling (TBC) experiments [5]. These results demonstrate that PR polymeric materials can reach performance levels that are competing with those of the best inorganic crystals, but with better processing capabilities.
6

Levenson, R., J. Liang, C. Rossier, M. Van Beylen, C. Samyn, F. Foll, Rousseau und J. Zyss. „Stability-Efficiency Trade-Off in Non-Linear Optical Polymers“. In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/otfa.1993.wd.6.

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Organic nonlinear optical materials have been the subject of increasing interest over the past decade[1]. Polymeric materials with highly polarizable molecules exhibit nonresonant NLO responses surpassing those obtained from traditional inorganic NLO materials, e.g. LiNbO3, KDP etc. Polymers offer the possibilities to optimize, by chemical synthesis, properties required for materials such as high mechanical and thermal stability. The dielectric constants of polymers ensure a very fast response-time for polymer devices [2], Compared to guest-host polymers, side chain polymers whereby NLO molecules are covalently attached lead to an increased density of nonlinear chromophores and may therefore exhibit higher nonlinear susceptibilities.
7

Wagner, Eva, Kathryn Uhrich und Thomas Twardowski. „Processing Considerations for Salicylic Acid-Based Polymers“. In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-55130.

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This paper describes some of the processing issues for extruding salicylic acid-based polymer prodrugs into fibers for medical devices. Polymeric prodrugs, in which a drug is polymerized in a degradable polymer that delivers controlled quantity of the drug to a targeted site in the body as the device degrades, are a new approach to controlled release. Hollow fibers were produced by solution spinning. Solid fibers were formed by melt processing. The salicylic acid polymers exhibited shear-thinning behavior. The viscosity exhibited pronounced temperature dependence.
8

Che, H., P. Vo und S. Yue. „Metallization of Various Polymers by Cold Spray“. In ITSC2017, herausgegeben von A. Agarwal, G. Bolelli, A. Concustell, Y. C. Lau, A. McDonald, F. L. Toma, E. Turunen und C. A. Widener. DVS Media GmbH, 2017. http://dx.doi.org/10.31399/asm.cp.itsc2017p0098.

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Abstract Previous results at McGill University have shown that metallic coatings can be successfully cold sprayed onto polymeric substrates. This paper studies the cold sprayability of various metal powders on different polymeric substrates. Five different substrates were used, including carbon fibre reinforced polymer (CFRP), acrylonitrile butadiene styrene (ABS), polyether ether ketone (PEEK), polyethylenimine (PEI); mild steel was also used as a bench mark substrate. The CFRP used in this work has a thermosetting matrix, and the ABS, PEEK, and PEI are all thermoplastic polymers, with different glass transition temperatures as well as a number of distinct mechanical properties. Three metal powders, tin, copper and iron, were cold sprayed with both a low-pressure system and a high-pressure system at various conditions. In general, cold spray on the thermoplastic polymers rendered more positive results than the thermosetting polymers, due to the local thermal softening mechanism in the thermoplastics. Thick copper coatings were successfully deposited on PEEK and PEI.
9

Möhlmann, G. R., W. H. G. Horsthuis, M. B. J. Diemeer, F. M. M. Suyten, E. S. Trommel, A. McDonach und N. McFadyen. „Optically Nonlinear Polymers in Guided Wave Electro-Optic Devices“. In Nonlinear Guided-Wave Phenomena. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/nlgwp.1989.fb4.

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Optically nonlinear polymers are attractive materials to be applied as active media in electro-optic devices. Polymeric multilayer structures, including an optically nonlinear waveguiding core, sandwiched between cladding layers and electrodes, have been produced. Monomode waveguides have been defined in the core of such multilayer structures. After electric field poling (156 V/µm) of the polymer core, r33 values up to 28 pm/V have been measured; to our knowledge the highest reported value thus far for an off-resonance electro-optic effect in polymers. Some devices have been made and tested. It may be expected that poling at higher field strengths will increase the polymeric device efficiency.
10

Patel, Hasmukh, Kenneth Johnson und Roland Martinez. „Triazine Polymers for Improving Elastic Properties in Oil Well Cements“. In SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204333-ms.

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Abstract The oil well cement placed in the annulus between casings and the formations experience high stresses under downhole conditions. These frequent stresses deteriorate the mechanical properties of cement and lead to the formation of micro-cracks and fractures, which affect production and increases the cost of operation. Although several polymeric materials have been employed to improve tensile properties of the cement, these additives have also adversely affected the compressive strength of the cement. A highly stable polymeric additive, triazine-based polymers, is designed, synthesized, and compounded with the cement to improve the tensile properties of the well-cement. Triazine polymer was characterized by fourier transform infrared spectroscopy and thermogravimetric analysis. The triazine polymer was mixed with cement and the cement slurries were cured at 180 °F under 3000 psi for 3 days. The set-cement samples were subjected to mechanical testing under high temperature and high pressure to study the elastic properties of the cement. The introduction of this polymer into the cement has improved the elastic properties of the cement with minimum reduction in compressive strength. The thickening time, dynamic compressive strength development, rheology, fluid loss properties, and brazilian tensile strength of the control and cement with triazine polymers were studied to understand the effect of this newly developed polymeric additive. The molecular interaction of the triazine polymer with cement particles has shown formation of covalent linkage between the polymer and cement particle. We have observed a 15 % decrease in Young's modulus for cement compounded with 2%wt. of triazine polymer, indicating the introduction of elastic properties in wellbore cement.

Berichte der Organisationen zum Thema "Polymers":

1

Stavland, Arne, Siv Marie Åsen, Arild Lohne, Olav Aursjø und Aksel Hiorth. Recommended polymer workflow: Lab (cm and m scale). University of Stavanger, November 2021. http://dx.doi.org/10.31265/usps.201.

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Polymer flooding is one of the most promising EOR methods (Smalley et al. 2018). It is well known and has been used successfully (Pye 1964; Standnes & Skjevrak 2014; Sheng et al. 2015). From a technical perspective we recommend that polymer flooding should be considered as a viable EOR method on the Norwegian Continental Shelf for the following reasons: 1. More oil can be produced with less water injected; this is particularly important for the NCS which are currently producing more water than oil 2. Polymers will increase the aerial sweep and improve the ultimate recovery, provided a proper injection strategy 3. Many polymer systems are available, and it should be possible to tailor their chemical composition to a wide range of reservoir conditions (temperature and salinity) 4. Polymer systems can be used to block water from short circuiting injection production wells 5. Polymer combined with low salinity injection water has many benefits: a lower polymer concentration can be used to reach target viscosity, less mechanical degradation, less adsorption, and a potential reduction in Sor due to a low salinity wettability effect. There are some hurdles when considering polymer flooding that needs to be considered: 1. Many polymer systems are not at the present considered as green chemicals; thus, reinjection of produced water is needed. However, results from polymer degradation studies in the IORCentre indicates that a. High molecular weight polymers are quickly degraded to low molecular weight. In case of accidental release to the ocean low molecular weight polymers are diluted and the lifetime of the spill might be quite short. According to Caulfield et al. (2002) HPAM is not toxic, and will not degrade to the more environmentally problematic acrylamide. b. In the DF report for environmental impact there are case studies using the DREAM model to predict the transport of chemical spills. This model is coupled with polymer (sun exposure) degradation data from the IORCentre to quantify the lifetime of polymer spills. This approach should be used for specific field cases to quantify the environmental risk factor. 2. Care must be taken to prepare the polymer solution offshore. Chokes and vales might be a challenge but can be mitigating according to the results from the large-scale testing done in the IORCentre (Stavland et al. 2021). None of the above-mentioned challenges are server enough to not consider polymer flooding. HPAM is neither toxic, nor bio-accumulable, or bio-persistent and the CO2 footprint from a polymer flood may be significantly less than a water flood (Dupuis et al. 2021). There are at least two contributing factors to this statement, which we will return in detail to in the next section i) during linear displacement polymer injection will produce more oil for the same amount of water injected, hence the lifetime of the field can be shortened ii) polymers increase the arial sweep reducing the need for wells.
2

Lambeth, Robert H., Randy A. Mrozek, Joseph L. Lenhart, Yelena R. Sliozberg und Jan W. Andzelm. Branched Polymers for Enhancing Polymer Gel Strength and Toughness. Fort Belvoir, VA: Defense Technical Information Center, Februar 2013. http://dx.doi.org/10.21236/ada577092.

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Bohnert, G. W. Conductive Polymers. Office of Scientific and Technical Information (OSTI), November 2002. http://dx.doi.org/10.2172/804936.

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Salovey, Ronald, und John J. Aklonis. The Behavior of Polymers Filled with Monodisperse Polymeric Beads. Fort Belvoir, VA: Defense Technical Information Center, November 1991. http://dx.doi.org/10.21236/ada242732.

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5

Pang, Yi. Exploring novel silicon-containing polymers---From preceramic polymers to conducting polymers with nonlinear optical properties. Office of Scientific and Technical Information (OSTI), Oktober 1991. http://dx.doi.org/10.2172/5097635.

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Russell, Thomas P. Interfacial Behavior of Polymers: Using Interfaces to Manipulate Polymers. Office of Scientific and Technical Information (OSTI), Februar 2015. http://dx.doi.org/10.2172/1171152.

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Lotufo, Guilherme, Mandy Michalsen, Danny Reible, Philip Gschwend, Upal Ghosh, Alan Kennedy, Kristen Kerns et al. Interlaboratory study of polyethylene and polydimethylsiloxane polymeric samplers for ex situ measurement of freely dissolved hydrophobic organic compounds in sediment porewater. Engineer Research and Development Center (U.S.), Mai 2024. http://dx.doi.org/10.21079/11681/48512.

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We evaluated the precision and accuracy of multilaboratory measurements for determining freely dissolved concentrations (Cfree) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediment porewater using polydimethylsiloxane and low-density polyethylene polymeric samplers. Four laboratories exposed performance reference compound (PRC) preloaded polymers to actively mixed and static ex situ sediment for approximately one month or more. For Cfree results, intralaboratory precision was high for single compounds; most PAHs and PCBs variability was low. Variability was higher for most hydrophobic PAHs, PCBs, and naphthalene, which were present at low concentrations and required larger PRC-based corrections. Intra- and interlaboratory variability between methods was low. Cfree polymer equilibrium was achieved in approximately one month during active exposures, suggesting using PRCs may be avoided for ex situ analysis using comparable active exposure; however, such testing may not reflect field conditions. Polymer-derived Cfree concentrations for most PCBs and PAHs averaged within a factor of 2 compared with concentrations in isolated porewater; difference factors of up to 6 were observed for naphthalene and the most hydrophobic PAHs and PCBs. Cfree results were similar for academic and private sector laboratories. The accuracy and precision demonstrated for determinating Cfree using polymer sampling are anticipated to increase regulatory acceptance and confidence.
8

Chiang, Martin Y. M., und Gregory B. McKenna. Hygrothermal effects on the performance of polymers and polymeric composites:. Gaithersburg, MD: National Institute of Standards and Technology, 1996. http://dx.doi.org/10.6028/nist.ir.5826.

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Kempel, Leo, und Shanker Balasubramaniam. RF Polymers II. Fort Belvoir, VA: Defense Technical Information Center, März 2009. http://dx.doi.org/10.21236/ada495291.

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Phillips, Shawn H., Timothy S. Haddad, Rusty L. Blanski, Andre Y. Lee und Richard A. Vaia. Molecularly Reinforced Polymers. Fort Belvoir, VA: Defense Technical Information Center, Juni 2001. http://dx.doi.org/10.21236/ada409917.

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