Materials Literature
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Aromatic polyesters, prepared by the reaction of aromatic dicarboxylic acids and 1,4-butanediol, were used to improve the toughness of bisphenol-A diglycidyl ether epoxy resin cured with p,p′-diaminodiphenyl sulfone. These polyesters contained poly(butylene phthalate)s (PBP), poly(butylene phthalate-co-butylene isopht…
The influence of thermal history on the properties of commercial P(3HB-co-12%-3HV) was studied. Thermogravimetric analysis and differential scanning calorimetry revealed that the plasticizer evaporated at 140°C or higher. The loss of plasticizer during thermal treatment at 170 and 180°C resulted in a slight increase o…
This article studies the influence of the heating rate and sample weight on the thermal decomposition of polystyrene (first-order kinetics). For this purpose, the kinetic parameters (i.e., frequency factor and activation energy), variables at the maximum decomposition rate (such as conversion, reaction rate, and tempe…
Microporous polypropylene sheets were prepared as follows. First, polypropylene pellet-containing CaCO3 filler was extruded to prepare base sheets, which were then biaxially stretched. The draft effect at the extrusion process was studied in relation to some properties of the resultant microporous polypropylene sheets…
Data on the tensile yield behavior of poly(vinyl chloride) (PVC), reported in the literature, are interpreted in terms of a model involving a cooperative movement of several independent structural units, all with the same activation enthalpy. This analysis leads to physical parameters such as the internal stress, acti…
Wood is an inexpensive filler that reduces the overall cost of polymer composites, with loss in some properties (e.g., ultimate strength, elongation, and water sorption often suffer with the addition of fillers) and a gain in others (e.g., Young modulus increment, reduced weight with respect to inorganic fillers, redu…
Cotton cellulosic fibers have been treated with alkyl isocyanates, modified polypropylene or other aliphatic agents in more or less swelling mediums. Their hydrophilicity can be reduced and this effect is studied by the associated techniques of microgravimetry and microcalorimetry. For the non-treated sample, a sorpti…
Blends of citrus pectin and several types of poly(vinyl alcohol) were investigated to determine the effects of compositional variables and polymer type on film properties. Some films were also plasticized with glycerol. Films were cast from water onto Lexan™ plates, dried, and removed. Thermomechanical properties were…
Vapor-deposited amorphous solid and hyperquenched glassy water were found to irreversibly transform, on compression at 77 kelvin, to a high-density amorphous solid. On heating at atmospheric pressure, this solid became viscous water (water B), with a reversible glass-liquid transition onset at 129 +/- 2 kelvin. A diff…
The effect of compatibilization on the morphology, mechanical properties, and dynamic mechanical properties of isotactic polypropylene (IPP)/nylon-6 (Ny-6) binary blends was investigated. Maleic anhydride (MAH) functionalized IPP was used as a compatibilizer in binary blends. The morphological, mechanical, and dynamic…
Talc-filled polypropylene (PP) composites were prepared by extrusion in a wide composition range (0–40 wt %). To improve the affinity relation between talc and the PP matrix, we modified the talc surface with silane coupling agents. Differential scanning calorimetry investigations on test samples, prepared by injectio…
Ab initio calculations indicate that the ground state for Ga adsorption on Al (100) is on-surface with local unit coverage. On Ga-coated Al (100), the bridge diffusion barrier for Al is large, but the Al$\rightarrow$Ga {\it exchange barrier is zero}: the ensuing incorporation of randomly deposited Al's into the Ga ove…
A simple analytic model of point-ion electrostatics has been previously proposed in which the magnitude of the net charge q_i on each atom in an ordered or random alloy depends linearly on the number N_i^(1) of unlike neighbors in its first coordination shell. Point charges extracted from recent large supercell (256-4…
The crystal of squaric acid (SQ) shows dielectric property caused by tautomerization coupled with intermolecular proton transfer. We prepared a squaric acid derivative, 1,4-phenylenebis(squaric acid) (PBSQ), and determined its crystal structure. In the unit cell one PBSQ molecule and two water molecules are incorporat…
An X-ray spectrometer which effectively integrates X-ray fluorescence and X-ray diffraction in a single instrument has been developed. The instrument uses same X-ray excitation, sample position, vacuum tank and control systems for both XRF and XRD measurements. It is shown that flexible elemental analysis together wit…
Chlorinated polyethylene (CPE) is used as an impact modifier for polypropylene (PP). Hytrel (a polyether ester block copolymer) acts as a compatibiliser for the system. Hytrel modified blends show good improvement in mechanical properties compared to unmodified blends. The modified blends can also accept 20% calcium c…
Surface stabilized ferroelectric liquid crystal (SSFLC) displays made of chiral smectic C* liquid crystals often present screening effects generally discussed in terms of the depolarizing field produced by ions attracted close to the electrodes. Here, we analyze the screening properties of distortions in the director…
Magnesium and calcium antimonites, which can coexist with MgO and CaO, respectively, were synthesized by a phase-equilibration technique and identified by X-ray diffraction to be MgSb2O4 and Ca4Sb2O7. To determine the standard Gibbs energies of formation of those antimonites, emf values of the following galvanic cells…
Elementary chemical reactions including volatile (gaseous) fission products, such as iodine and cesium, are analyzed from the first principle, so as to enable us to study the kinetic behavior (non-equilibrium state) of fission products in severe light water reactor accidents without experimental rate constants. Activa…
The temperature dependence of the parameters characterizing the first peak in the S(Q) and S(Q,E=0) diffraction patterns of vitreous boron trioxide is considered in some detail. The analysis of the experimental spectra is aided by results derived from molecular-dynamics simulations, which enable us to isolate the most…