Materials Literature
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Abstract Copolyamides of nylon‐4,6 and nylon‐4,T were prepared by a two‐step method: (1) a prepolymerization in an autoclave (40 min at 210°C) and (2) a postcondensation in the solid state (4 h, 260°C). On these materials was studied the melting behavior with DSC, the crystalline structure with WAXS, the water absorpt…
Abstract When PVC films containing zinc(II) chloride were heated in the temperature range 65–95°C, broad absorptions developed in the 250–900 nm region with maxima around 610 nm. The development of the color, the rate of which was proportional to the ZnCl 2 content, was preceded by an induction period, the length of w…
Abstract Polyamides containing arylene sulfone ether linkages were synthesized from 4,4′‐[sulfonylbis( p ‐phenyleneoxy)] dibenzoyl chloride (SPCI), 3,3′‐[sulfonylbis( p ‐phenyleneoxy)] dibenzoyl chloride (SMCl), and arylene sulfone ether diamines (SED), by solution and interfacial polymerization techniques. In solutio…
Filament-assisted chemical vapor deposition (CVD) diamond film growth on Si(100) was studied using x-ray photoelectron spectroscopy (XPS) to examine the sample at selected intervals during the nucleation and growth processes. The sample was transferred under vacuum from the growth chamber to the attached XPS analysis…
Abstract A detailed study has been made of the thermal cure of two polyimides using infrared analysis. It is shown that two of the IR bands commonly used to determine the amount of imidization are affected by both interference from other species and by polymer morphology. These bands, located near 1780 cm −1 and 730 c…
Magnetic properties of the series of ThMn 12 -structure intermetallic compounds R(Fe 11 Ti) have been determined for rare earths from Nd to Lu plus Y. The highest Curie temperature (607 K) is for R=Gd, and R-Fe exchange interactions are much stronger for light rare earths than for heavy ones. The temperature dependenc…
An amorphous carbon structure is obtained with a computer simulation based on a first-principles molecular-dynamics method, in which the interatomic potential is constructed directly from the electronic ground state, using density-functional techniques. From our results, which agree well with the limited experimental…
To overcome the disadvantages of glutaraldehyde (GA), new cross-linking reagents, polyepoxy compounds (PC), were introduced and their effects on the antigenicity and immunogenicity of biomaterials were investigated. In the qualitative study, antigenicity of type I collagen in bovine arteries treated with GA or glycero…
Glucose oxidase (GOD) was immobilized in Bombyx mori silk fibroin membrane by only physical treatment, i.e., stretching without any chemical reagents. This is due to the structural transition of the silk fibroin membrane from random coil to antiparallel beta-sheet (Silk II) induced by the stretching treatment. Permeab…
The nature of the low-temperature (T approximately=90 K) magnetic phase transition in cubic Laves-phase Ce(Fe 1-x Co x ) 2 compounds with x=0.15, 0.20 has been determined using powder neutron diffraction measurements. Below this temperature, ferromagnetism is replaced by an antiferromagnetic phase, which consists of (…
The use of surface charging of a thin dielectric film on a semiconductor during x-ray photoelectron spectroscopic analysis has been investigated. The binding energy shifts measured from 1.5 nm SiO2/p-Si and 4 nm Si3N4/n-InP indicate that a positive surface potential can be induced by the loss of photoelectrons in the…
We report the observation of spin-polarized photoelectron diffraction for antiferromagnetic MnO(001). Data at kinetic energies near 100 eV for the spin-split Mn $3s$ multiplet show abrupt changes in the $^{5}S:^{7}S$ intensity ratio at a temperature of 530\ifmmode\pm\else\textpm\fi{}20 K that is 4.5 times the N\'eel t…
Major progress has been made in understanding the complicated magnetic structures exhibited by dhcp neodymium metal. New evidence for the 2-q model of the structure between 19.1 and 9 K has been discovered in neutron-diffraction studies of intermodulation harmonics of the type $2{\mathrm{q}}_{i}\ifmmode\pm\else\textpm…
Abstract Compounds of natural rubber, styrene‐butadiene rubber, and butadiene rubber are vulcanized at different temperatures and the crosslink density and physical properties of the vulcanizates are compared. It is found that for each compound there is an optimum vulcanization temperature which results in the best co…
Abstract A heretofore uninvestigated approach to the production of cellulose acetate, the acetylation of whole wood pulp with subsequent isolation of the cellulose derivative by differential solubility, is described. The mechanical pulp used was produced by refining aspen wood chips with a disc refiner. Two convention…
Abstract Light‐induced yellowing of extruded rigid poly(vinyl chloride) formulations containing 0, 2.5, and 5 phr of titanium dioxide under exposure to monochromatic light was studied. Both photoyellowing and photobleaching were observed as wavelength‐dependent phenomena in the range of 280–500 nm. Action spectra for…
Abstract Linear low density polyethylene (LLDPE) was reinforced with different wood fibers, aspen chemithermomechanical pulp (bleached and unbleached), and other commerical wood pulps. Silane coupling agents A‐172, A‐174, A‐1100, and polymethylene polyphenyl isocyanate were used to improve the bonding between the fibe…
The fabrication of a miniature low power/high voltage thermoelectric convertor is described. The device which has arisen out of a requirement of the British gas industry for an autonomous source of electrical power for use in consumers' gas monitoring systems, generates fractions of a microwatt at several volts.
A phenomenological theory has been used to calculate the minimum thermal conductivity for 17 alkali halides with the NaCl structure in the temperature range 1-1200 K. The shortest mean free path has been chosen to be either the nearest-neighbour distance or the phonon wavelength. The calculations show that minimum the…
Grain boundary strengths are estimated experimentally for various Al2O3 structures. It turns out that grain boundary strength at room temperature is strongly affected by viscose relaxation processes proceeding during cooling the sintered structures. The results are used to discuss associated macroscopic mechanical pro…