Showing papers on "Polymer published in 1986"

The theory of polymer dynamics

Abstract: Introduction Static properties of polymers Brownian motion Dynamics of flexible polymers in dilute solution Many chain systems Dynamics of a polymer in a fixed network Molecular theory for the viscoelasticity of polymeric liquids Dilute solutions of rigid rodlike polymers Semidilute solutions of rigid rodlike polymers Concentrated solutions of rigid rodlike polymers Index.

Handbook of conducting polymers

Abstract: Volume 1: Conjugated Polymers: Theory, Synthesis, Properties, and Characterization PART 1: THEORY OF CONJUGATED POLYMERS On the Transport, Optical, and Self-Assembly Properties of -Conjugated Materials: A Combined Theoretical/Experimental Insight D. Beljonne, J. Cornil, V. Coropceanu, D.A. da Silva Filho, V. Geskin, R. Lazzaroni, P. Leclere, and J.-L. Bredas Theoretical Studies of Electron-Lattice Dynamics in Organic Systems S. Stafstroem PART 2: SYNTHESIS AND CLASSES OF CONJUGATED POLYMERS Helical Polyacetylene Synthesized in Chiral Nematic Liquid Crystals K. Akagi Synthesis and Properties of Poly(arylene vinylene)s A.C. Grimsdale and A.B. Holmes Blue-Emitting Poly(para-Phenylene)-Type Polymers E.J.W. List and U. Scherf Poly(paraPhenyleneethynylene)s and Poly(aryleneethynylene)s: Materials with a Bright Future U.H.F. Bunz Polyaniline Nanofibers: Synthesis, Properties, and Applications J. Huang and R.B. Kaner Recent Advances in Polypyrrole S.H. Cho, K.T. Song, and J.Y. Lee Regioregular Polythiophenes M. Jeffries-El and R.D. McCullough Poly(3,4-Ethylenedioxythiophene)-Scientific Importance, Remarkable Properties, and Applications S. Kirchmeyer, K. Reuter, and J.C. Simpson Thienothiophenes: From Monomers to Polymers G.A. Sotzing, V. Seshadri, and F.J. Waller Low Bandgap Conducting Polymers S.C. Rasmussen and M. Pomerantz Advanced Functional Polythiophenes Based on Tailored Precursors P. Blanchard, P. Leriche, P. Frere, and J. Roncali Structure-Property Relationships and Applications of Conjugated Polyelectrolytes K.S. Schanze and X. Zhao PART 3: PROPERTIES AND CHARACTERIZATION OF CONJUGATED POLYMERS Insulator-Metal Transition and Metallic State in Conducting Polymers A.J. Epstein One-Dimensional Charge Transport in Conducting Polymer Nanofibers A.N. Aleshin and Y.W. Park Structure Studies of - and - Conjugated Polymers M.J. Winokur Electrochemistry of Conducting Polymers P. Audebert and F. Miomandre Internal Fields and Electrode Interfaces in Organic Semiconductor Devices: Noninvasive Investigations via Electroabsorption T.M. Brown and F. Cacialli Electrochromism of Conjugated Conducting Polymers A.L. Dyer and J.R. Reynolds Photoelectron Spectroscopy of Conjugated Polymers M.P. de Jong, G. Greczyniski, W. Osikowicz, R. Friedlein, X. Crispin, M. Fahlman, and W.R. Salaneck Ultrafast Exciton Dynamics and Laser Action in -ConjugatedSemiconductors Z. Valy Vardeny and O. Korovyanko Volume 2: Conjugated Polymers: Processing and Applications PART 1: PROCESSING OF CONJUGATED POLYMERS Conductive Polymers as Organic Nanometals B. Wessling Conducting Polymer Fiber Production and Applications I.D. Norris and B.R. Mattes Inkjet Printing and Patterning of PEDOT-PSS: Application to Optoelectronic Devices Y. Yoshioka and G.E. Jabbour Printing Organic Electronics on Flexible Substrates N.D. Robinson and M. Berggren PART 2: APPLICATIONS AND DEVICES BASED ON CONJUGATED POLYMERS Polymers for Use in Polymeric Light-Emitting Diodes: Structure-Property Relationships H. Christian-Pandya, S. Vaidyanathan, and M. Galvin Organic Electro-Optic Materials L.R. Dalton Conjugated Polymer Electronics-Engineering Materials and Devices N. Tessler, J. Veres, O. Globerman, N. Rappaport, Y. Preezant, Y. Roichman, O. Solomesch, S. Tal, E. Gershman, M. Adler, V. Zolotarev, V. Gorelik, and Y. Eichen Electrical Bistable Polymer Films and Their Applications in Memory Devices J. Ouyang, C.-W. Chu, R.J. Tseng, A. Prakash, and Y. Yang Electroactive Polymers for Batteries and Supercapacitors J.A. Irvin, D.J. Irvin, and J.D. Stenger-Smith Conjugated Polymer-Based Photovoltaic Devices A.J. Mozer and N.S. Sariciftci Biomedical Applications of Inherently Conducting Polymers (ICPs),P.C. Innis, S.E. Moulton, and G.G. Wallace Biosensors Based on Conducting Electroactive Polymers S. Brahim, A.M. Wilson, and A. Guiseppi-Elie Optical Biosensors Based on Conjugated Polymers K. Peter, R. Nilsson, and O. Inganas Conjugated Polymers for Microelectromechanical and Other Microdevices G.M. Spinks and E. Smela Corrosion Protection Using Conducting Polymers D.E. Tallman and G.P. Bierwagen Artificial Muscles T.F. Otero

Introduction to physical polymer science

Abstract: Chain Structure and Configuration. Molecular Weights and Sizes. Concentrated Solutions and Phase Separation Behavior. The Amorphous State. The Crystalline State. Polymers in the Liquid Crystalline State. Glass-Rubber Transition Behavior. Cross-Linked Polymers and Rubber Elasticity. Polymer Viscoelasticity and Rheology. Mechanical Behavior of Polymers. Modern Topics. Index.

Analysis of Linear Viscoelasticity of a Crosslinking Polymer at the Gel Point

Abstract: We suggest a very simple memory integral constitutive equation for the stress in crosslinking polymers at their transition from liquid to solid state (gel point). The equation allows for only a single (!) material parameter, the strength S[Pas1/2], and it is able to describe every known viscoelastic phenomenon at the gel point. Measurements were performed on polydimethylsiloxane model networks with balanced stoichiometry for which the crosslinking reaction has been stopped at different degrees of conversion. At the gel point, the loss and storage moduli were found to be congruent and proportional to ω1/2 over a wide range of temperature (−50°C to +180°C) and five decades of frequency ω. The hypothesis is made that this behavior is valid in the entire range 0<ω<∞. This congruence hypothesis is consistent with the Kramers‐Kronig relation and leads to a constitutive equation which shows that, for our polymer, congruent functions G′(ω)=G″(ω) are as much a rheological property at the gel point as are infinite ...

Hydrogen bonding in polymers. 4. Infrared temperature studies of a simple polyurethane

Abstract: Etude d'un polyurethanne lineaire semi-cristallin, aliphatique le polybutylene-1,4 hexamethylenecarbamate. Comparaison avec un polyamide semicristallin

The permeability of fibrous porous media

Abstract: The literature was searched for experiments and theories related to low-Reynolds-number flow through fibrous porous media, particularly highly porous structures. Experimental data were found for a wide range of materials, from polymer chains to fiberglass, and the results collapse reasonably well when the appropriate dimensionless co-ordinates are employed. Of the theories, accurate solutions of Stokes equation are available for regular arrays of parallel rods, either aligned with or normal to the flow. For irregular arrays and three-dimensional media, approximate permeabilities can be calculated from several flow models.

Theory of lyotropic polymer liquid crystals

Abstract: Revue; influence du troisieme coefficient du viriel, de la charge, de la semiflexibilite de la bidispersite et de la polydispersite. Transition de phase isotrope nematique. Extension de la theorie d'Onsager

Hydrolysis of titanium alkoxide and effects of hydrolytic polycondensation parameters

Abstract: Titanium alkoxides hydrolyse vigorously with water producing polycondensates whose equivalent oxide content varies from ∼ 70% to over 90%. This variation reflects the average molecular size and the nature of the terminal bonds. Hydrolysis conditions also affect the molecular and particle morphologies modifying the crystallization and sintering behaviour of oxide materials derived from polycondensates. It is also possible to form clear polymer solutions under excess water hydrolysis with the addition of certain acids. Investigations show that there is a window in the acid concentration which provides long-term solution stability. The gels formed from these clear solutions shrink in their liquor under certain conditions and the introduction of hydrogen peroxide into the liquor (surrounding the gel) causes vigorous gel shrinkage.

Hydrogen bonding in polymers. 2. Infrared temperature studies of nylon 11

Abstract: Les resultats d'etudes precedentes sur les polyamides amorphes sont applicables a ce polymere semi-cristallin

Electroactive polymers and macromolecular electronics.

Abstract: Electrodes can be coated with electrochemically reactive polymers in several microstructural formats called sandwich, array, bilayer, micro-, and ion-gate electrodes. These microstructures can be used to study the transport of electrons and ions through the polymers as a function of the polymer oxidation state, which is essential for understanding the conductivity properties of these new chemical materials. The microstructures also exhibit potentially useful electrical and optical responses, including current rectification, charge storage and amplification, electron-hole pair separation, and gates for ion flow.

Use of degradable ball sealers to seal casing perforations in well treatment fluid diversion

Abstract: Plugging perforations in casing in a wellbore penetrating a subterranean formation using degradale ball sealers. The ball sealer used is composed of a polyester polymer which is substantially insoluble in the wellbore fluid. The polymer degrades in the presence of water at an elevated temperature to form small molecules which are soluble in a fluid in the subterranean formation. After the polymer degrades, the flow through the perforation returns to substantially its initial value.

Critical phenomena and transitions in swollen polymer networks and in linear macromolecules

Abstract: Formulation de l'energie libre de dilution de reseaux. Cas de reseaux non charges et ioniques ou une petite proportion de groupes ionisables modifie le comportement thermodynamique

The structure of thermotropic copolyesters

Abstract: Highly oriented polymeric products have been produced over the past fifteen years by two very different processing routes; from conventional polymers processed to highly oriented extended chain structures, and from “rod-like” polymers which exhibit liquid crystalline behaviour. Gel spun polyethylene is an example of such a conventional polymer. There are three main types of liquid crystalline polymers (LCP) which have high orientation and modulus: lyotropic aramids, such as poly(ρ-phenylene terephthalamide) (PPTA); lyotropic, aromatic heterocyclic polymers, or “ordered polymers”; and the family of thermotropic aromatic copolyesters. Extensive characterization of the thermotropic copolyesters has resulted in the delineation of a fibrillar, hierarchial structural model which accounts for the structures observed in a broad range of oriented fibres, extrudates and moulded articles. Three distinct fibrillar species are observed: microfibrils that are about 50 nm, fibrils about 500 nm, and macrofibrils about 5μm, in size. Superimposed on the structural hierarchy is a defect hierarchy, defined by the regular meander of the molecular chain and a localization of defects within a microfibril at about a 50 nm periodicity. Orientational variations, layering and skin core structures, in thick specimens, are the result of local flow fields on the basic structural units during solidification. The fibrillar textures appear to be present prior to any preparation for microscopy. A wide range of specimen preparation methods, i.e. fractography, sonication, microtomy and etching, and microscopic techniques, i.e. optical, scanning and transmission electron microscopy, were applied to the characterization of the aromatic copolyesters and PPTA. Interestingly, the same basic hierarchy is observed for both the lyotropic and the thermotropic LCPs and the microfibrillar structures of all the highly oriented polymers, including polyethylene, appear quite similar.

Fluorescence probes for polymer free-volume

Abstract: A series of fluorescence probes (p-(N,N-dialkylamino) benzylidene malononitriles) which belong to a class of organic compounds known as “molecular rotors” has been developed. The internal molecular rotation of these compounds can be slowed down by increasing the surrounding media rigidity, viscosity or decreasing the free-volume available for molecular relaxation. Inhibition of internal molecular rotation of the probe leads to a decrease in the non-radiative decay rate and consequently enhancement of fluorescence. This behavior can be used to study both the static and dynamic changes in free-volume of polymers as a function of polymerization reaction parameters, molecular weight, stereo regularity, crosslinking, polymer chain relaxation and flexibility. In addition, the dependence of the fluorescence emission maximum of these probes on media polarity allow continuous monitoring of the probes location in the polymer matrix. These fluorescence materials are capable of simultaneously probing the flexibility and polarity of the surrounding media.

Polynucleotide assay reagent and method

Abstract: A diagnostic reagent and system for determination of a single-stranded polynucleotide analyte having a selected target sequence. The reagent includes a solid support and multiple support-bound polymers designed to bind specifically to the analyte. Each polymer is composed of a sequence of base-complementary recognition moieties which can bind specifically to corresponding in-sequence bases in the analyte target sequence, and an unbranched, stereoregular backbone whose charge density is substantially less than that of the polynucleotide analyte. A reporter in the system contains a polycationic tail adapted to bind to the analyte, under conditions in which the reporter does not bind to the less densely charged polymers, and reporter groups by which the presence of the reporter can be detected.

Changes in adsorbed fibrinogen and albumin interactions with polymers indicated by decreases in detergent elutability

Abstract: The adsorption of proteins to polymers is typically irreversible. Even the use of detergents does not elute all the adsorbed protein from all polymers. The fundamental reasons for such apparently tight protein binding are not well understood, so a study of several aspects of elution was undertaken. A method for examining the interaction of proteins at the protein/polymer interface using SDS elutability as a measure of the protein-surface interaction strength was developed. The effects of polymer type, elution agent, elution conditions, protein type, protein concentration, sample age, and storage temperature on elutability were examined. The results show that protein elutability from polymers decreases slowly over a period of days at 4°C but proceeds much more rapidly at elevated temperatures. The results indicate that protein denaturation may be responsible for both the initial incomplete elution and the decreases in SDS elutability of fibrinogen and albumin from polymers with time.

Sol-gel chemistry studied by 1H and 29Si nuclear magnetic resonance

Abstract: The sol-gel process for forming inorganic glasses and ceramics can be studied uniquely at the molecular level by using 1 H and 29 Si nuclear magnetic resonance (NMR). A variety of reaction conditions have been investigated, and resonances for hydrolysis products, oligomers, and polymers have been identified. Differences resulting from variations in pH, water/alkoxide ratio, starting material, solvent, and addition of a second network-forming oxide are discussed. The effects of ester interchange were observed in 29 Si NMR spectra. The structural makeup of the polymer formed was studied as a function of pH. The hydrolysis was followed with 1 H NMR spectroscopy. All reactions were of tetramethyl or tetraethyl orthosilicate in methanol or ethanol.

A study on polymer blending microrheology: Part IV. The influence of coalescence on blend morphology origination

Abstract: The influence of shear induced coalescence on the origination of morphologies in polymer blending processes is investigated both theoretically and experimentally. In the theoretical part a route is proposed to estimate the fraction of collisions between disperse phase domains in simple shear flow that result in an actual coalescence. It was shown that under polymer blending conditions this “coalescence probability” is only substantial if the polymer/polymer interfaces exhibit a high degree of mobility. In the experimental part, the phenomenon of gravity induced droplet/planar interface coalescence is utilized to show the high degree of mobility of molten polymer interfaces. Seoul experiments on the relation between domain size and disperse phase concentration in polymer blends prepared on a single screw extruder were carried out. For extremely low concentration (<½ %) the domain size could be predicted satisfactorily by means of Taylor's classical criterion for Newtonian liquids, while at higher concentration coalescence increased the average domain size manifold.

Thermally conductive polymer compositions

Abstract: While polymers are widely used for their excellent insulating properties, there is a growing need for thermally conductive polymer compounds. The thermal conductivity of metal particle, mineral particle, and carbon fiber filled compounds are examined at volume concentrations up to the maximum packing fraction of each filler. From these data the coefficients in Nielsen's model were determined for each type of filler. Gaps in available thermal conductivity data were then predicted using these coefficients, the properties of the polymer and filler, and the volume concentration of the filler. Gaps were found to exist mostly for compounds containing short fiber reinforced compounds. A comparison of predicted values of thermal conductivity for such systems with the sparse data available shows that Nielsen's model cannot be applied to highly filled fiber reinforced composites because it cannot account for the anisotropy of such compositions.

Polymer-polymer miscibility

Abstract: The theoretical and practical aspects of polymer-polymer miscibility in the solid amorphous state are reviewed. The polymers include homopolymers and both random and block copolymers. Although present theoretical treatments of polymer-polymer miscibility all contain the random mixing hypothesis and are thus not applicable to mixtures that involve specific interactions between the components, most of the observed singlephase polymer-polymer mixtures involve hydrogen-bonding or other specific interactions between the components. Even in the absence of specific interactions, the composition of a random copolymer can often be tailored to provide miscibility with a particular homopolyner. Many polymer-polymer mixtures have lower critical solution temperatures, and a small number of such mixtures have given indications of upper critical solution temperatures. The special phenomena that may be observed when other polymers are mixed with block copolymers are discussed.

Enzyme-analog built polymers. 20. Molecular recognition through the exact placement of functional groups on rigid matrixes via a template approach

Abstract: Introduction de 2 groupes amino a l'aide d'une matrice a une distance distincte dans des polymeres reticules

The Recent Developments of Thermotropic Liquid Crystalline Polymers

Abstract: The historical development of both main-chain (M.C.) and side-chain (S.C.) liquid crystalline polymers (LCPs) is presented. Synthetic routes and characterization techniques for LCPs are introduced. Various approaches to reduce the melting points of M.C. LCPs and to increase the mesogenic order of S.C. LCPs are reviewed and evaluated. The criteria to form a liquid crystalline phase are then discussed. Comparisons among thermotropic, lyotropic, and low-molecular-weight liquid crystals are also made. It is concluded that the preparation of LCPs has been well developed by the industry, but that the understanding of the formation of LC domains has not been completely understood. The theoretical explanations for some unexpected results are still not available. These anomalies are detailed in this work. Future research activity en LCPs for plastics engineers is also mentioned in this article.