Materials Literature
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A systematic modeling analysis for polyaddition of isophorone diisocyanate to poly(oxyethylene) glycol, poly(oxypropylene) glycol, and poly(oxytetramethylene) glycol (PEG−PPG−PTMG) ternary polyol-based waterborne polyurethane (PU) synthesized by a modified acetone process was performed. Using a mixture of experimental…
The thermal diffusivity of bulk ${\mathrm{Ge}}_{\mathrm{x}}$${\mathrm{As}}_{40\mathrm{\ensuremath{-}}\mathrm{x}}$Se(S${)}_{60}$ glasses has been measured by an optical beam deflection method as a function of the composition. The dependence of the thermal diffusivity of both the families on the average coordination num…
The phase behavior of dimerizing (associating) rigid particles is studied by both theory and computer simulation. The model molecule comprises a hard spherocylinder of length L and diameter D with a terminal square well bonding site embedded in one of the hemispherical caps. This model mimics the properties of simple…
We report the generation of fullerenes and nanotubes using an arc discharge on graphite in a high-pressure nozzle. The vapour from the arc is quenched via collisions with helium gas, forming carbon clusters within a localized highpressure region. The carbon molecules are entrained in the gas jet as it expands into the…
Silicon carbide (SiC) whiskers were formed by microwave and conventional heating in the present study. SiC whiskers with diameters in the nanometer range were synthesized by reducing silica (SiO 2 ) with various forms of carbon in a microwave furnace. Ultrafine SiO 2 powder, char, phenolformaldehyde resin, and carbon…
The strong prolate anisotropy of the backbone conformation observed in the nematic phase of ‘side-on fixed’ LCP is found to be as great as for main chain LCP. From this remark originated this SANS study of a ‘jacketed’ polymer PA4,4,4. A form factor of cylinders is used to model the experimental scattering data as in…
Introduction and synopsis Foams have unique thermal, electrical and acoustic properties. Among these are: exceptionally low thermal conductivity, making them a prime choice for thermal insulation; very low dielectric loss, allowing transmission of microwaves without attenuation or scattering; and the ability to absorb…
Abstract Blends of high‐density polyethylene (HDPE) with novel linear low‐density polyethylene (LLDPE) samples in the whole range of compositions were investigated by means of differential scanning calorimetry (DSC), small‐angle X‐ray scattering (SAXS) and wide‐angle X‐ray diffraction (WAXD). The LLDPEs are ethylene/o…
Reverse mode properties have been achieved in novel polymer dispersed liquid crystal (PDLC) cells using a UV curable liquid crystal (LC) as a polymer matrix. A homogeneously aligned PDLC cell is composed of a nematic LC with positive dielectric anisotropy and the UV curable LC. Another type of the PDLC cell where the…
Abstract The calculations of the mean‐square radius of gyration for more than thirty sorts of polymer chains are reviewed on the basis of a unified approach. A general expression of the mean‐square radius of gyration was developed for polymer chains with side groups and/or heteroatoms. It consists of two parts. The fi…
The relevance of powder packing structure and microstructure in alumina ceramics made through the injection molding process was investigated in the present study. The packing structure of oriented powder particles was retained in the present ceramics after sintering. Even after significant growth, the orientation of t…
This research investigates the infrared absorption intensity and isotope-dependent frequency shifts of CH stretching on diamond C(111) single-crystal surfaces by Fourier transform infrared spectroscopy (IRS). By employing single-pass direct absorption and in situ surface oxidation methods, a single sharp feature at νm…
Ultraviolet probe ion and far-infrared spectroscopic results for barium borate glasses indicate the existence of two types of cation-hosting site differing in electron density, that is, basicity. The pattern is similar to the sodium borate glass system, which has the same average theoretical optical basicity trend. Ho…
The established pathway for the last two steps in purine biosynthesis, the conversion of 5-aminoimidazole-4-carboxamide ribonucleotide (ZMP) to IMP, is known to utilize 10-formyl-tetrahydrofolate as the required C1 donor cofactor. The biosynthetic conversion of ZMP to IMP in three members of the domain Archaea, Methan…
This paper describes the properties of some new organic–inorganic photochromic layers. They are based on a hybrid organic–inorganic matrix in which tungsten heteropolyoxometallates (SiW12O4−40, PW12O3−40) are entrapped in a network obtained from the reaction of 3-glycidoxy-propyltrimethoxysilane. The high homogeneity…
Abstract A comparison was made of the room temperature strain-crystallization of naturally-occurring cis -1,4-polyisoprenes having varying non-rubber content. A variety of measurements were employed to assess crystallization, including stress relaxation, optical birefringence, and the infrared absorption spectrum. All…
Among the developments associated with sol-gel materials, of relevance is the entrapment of photochromic molecules. Photochromic-doped sol-gel gel-glasses can be prepared by adding a spiropyrane photochromic dye to a solution of ethoxy silane monomers containing non-reacting ethyl radicals. After polymerization, norma…
Liquid-liquid dispersions with drop sizes less than 100 μm cannot be separated using gravity settlers, but need more effective separation tools. In this situation fibre beds represent a relatively simple and low-cost form of pre-separation equipment to enlarge the droplets by drop coalescence as a first step in gravit…
Dielectric properties of quantum paraelectric materials, SrTiO3, CaTiO3 and (La1/2Na1/2)TiO3, were presented and discussed since they show the titled dielectric properties in the lowest temperature range. In order to show our strategy to obtain the titled materials for microwave resonator applications, dielectric prop…
The sorption of Thermomonospora fusca E3 and E5 and Trichoderma reesei CBHI cellulases on bacterial microcrystalline cellulose (BMCC) was investigated to measure binding reversibility and surface exchange. The adsorption and desorption curves for CBHI were comparable; this suggests a totally reversible binding process…