Materials Literature
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Supramolecular side-chain liquid crystalline polymers with various kinked pendant groups are constructed from positional isomers of proton acceptor monomers and donor polymers (with different molecular weights) through hydrogen bonding. Monomer−monomer complexes of similar structures are built to compare the influence…
Low-viscosity, methoxylated polysiloxane resins incorporating Me2SiO2/2 (D) and SiO4/2 (Q) units were prepared using nonhydrolytic condensation between Si—Cl and Si—OMe groups with the formation of MeCl, catalyzed by a Lewis acid. With the commonly used catalysts, condensation between two Si—OMe groups, with formation…
The miscibility, intermolecular interactions and thermal behavior of the poly(hydroxy ether of Bisphenol A) (Phenoxy)/poly(ethyl oxazoline) (PEOx) blends were investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and high-resolution solid-state nuclear magnetic resona…
New poly(amide–imide)s were prepared from a diimide–dicarboxylic acid, 1,4-bis(4-trimellitimidophenoxy)-2-tert-butylbenzene (BTTB), with various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. The new diimide–dicarboxylic acid BTTB…
The atomic force microscope (AFM) has been used to investigate morphological development during the crystallization of poly(ethylene oxide) (PEO) from the melt. PEOs with molecular weights of 1 × 105 and 7 × 106 were used. Height and amplitude images were recorded, using the tapping mode. For both polymers, the mode o…
Narrow disperse micron-range divinylbenzene-maleic anhydride microspheres have been prepared in near quantitative yields using precipitation polymerization. A variety of solvents were investigated for use as the reaction medium with a 40:60 mixture of methyl ethyl ketone and heptane providing the best results. The eff…
New polyarylates having benzopinacolone units were synthesized from 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone and aromatic dicarboxylic acid chlorides. The polymers having an inherent viscosity of 0.71–0.94 dL/g were obtained by the two-phase method using toluene as an organic solvent. The polymers were easily sol…
We studied the photolysis of a fluoroethylene–fluoropropylene copolymer (FEP) film by vacuum ultraviolet (VUV) radiation from a resonance Xe lamp at a wavelength of 147 nm and air pressures of 0.05 and 2.5 Torr. The chemical changes in the FEP surface layer were investigated by Fourier-transform infrared spectroscopy…
The mechanism of thermal degradation of homopolymers of styrene (St) and methacrylonitrile (MAN) and their copolymers was investigated theoretically and experimentally by the pyrolysis gas chromatography using a Curie-point pyrolyzer. Poly(St-co-MAN)s generate dimers and trimers as well as monomers by flash pyrolysis.…
A two-dimensional conducting polyaniline (PAN) monolayer has been formed on an electrically insulating monolayer. The approach is based on the electrochemical polymerization of surface-confined anilinium ions that were electrostatically attached to a negatively charged self-assembled monolayer of ω-mercaptodecanesulfo…
The conditions for the crystallization of form II of syndiotactic polypropylene are described. As-prepared, melt-crystallized, and oriented-fiber specimens of different samples of syndiotactic polypropylene having different degrees of stereoregularity, prepared with a metallocene-based catalyst as well as with the tra…
Thermoplastic elastomer gels (TPEGs) composed of a poly[styrene-b-(ethylene-co-butylene)-b-styrene] triblock copolymer and a low-volatility, midblock-compatible mineral oil have been investigated at different oil concentrations to ascertain the effect of composition on TPEG morphology and mechanical properties. The im…
A positive-working photosensitive polyimide precursor based on fluorinated poly(amic acid) (FPAA) and 2,3,4-tris(1-oxo-2-diazonaphthoquinon-4-ylsulfonyloxy)benzophenone (D4SB) as a photosensitive compound has been developed. FPAA was prepared by ring-opening polyaddition of dianhydrides, pyromellitic dianhydride and b…
In the search for new packaging materials for the electrical/electronics industry, three types of polymer composites have been studied. Silicone/boron nitride powders, polyurethane/alumina powders, and polyurethane/carbon fibers have all been synthesized to study the moisture–absorption kinetics, thermal conductivitie…
This paper investigates sulfur poisoning and catalyst regeneration for alumina-supported platinum, palladium, and rhodium catalysts. Reduced catalysts and regenerated sulfur-poisoned catalysts were studied for their activity in the catalytic combustion of methane in a flow microreactor. CO adsorption, in conjunction w…
Adsorption of poly( tert -butylstyrene)/poly(styrenesulfonate) diblocks on polystyrene latices from water is reported and interpreted with scaling theories to demonstrate the effects of ionic strength and curvature on layer thickness. The adsorbed amount increases with ionic strength from no added salt to 0.1 M, formi…
A new adamantane-based dietheramine, 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane, was prepared in two steps from chloro displacement of p -chloronitrobenzene with the potassium phenolate of 2,2-bis(4-hydroxyphenyl)adamantane, followed by hydrazine catalytic reduction of the intermediate dinitro compound. A series of p…
Using molecular dynamics simulations, with a realistic many-body embedded-atom potential, and a novel method to characterize local order, we study the structure of pure nickel during the rapid quench of the liquid and in the resulting glass. In contrast with previous simulations with pair potentials, we find more crys…
Organosilicon carbodiimides have been successfully applied as single-source precursor compounds for the synthesis of novel ternary Si-, C-, and N-containing solid phases. Their thermally induced decomposition gives either amorphous silicon carbonitrides or polycrystalline silicon nitride and silicon carbide mixtures,…
The free-carrier screening of macroscopic polarization fields in wurtzite GaN/InGaN quantum wells lasers is investigated via a self-consistent tight-binding approach. We show that the high carrier concentrations found experimentally in nitride laser structures effectively screen the built-in spontaneous and piezoelect…