Materials Literature
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Abstract We carried out a feasibility study of the use of black rice husk ash (RHA) as a filler in epoxy resin for embedding material in electrical and electronic applications. We made a comparison by mixing RHA and two commercial fillers, fused and crystalline silica, with epoxy resin at weight fractions ranging from…
Abstract Optically active alicyclic polyimides were prepared for the first time from (−)‐[1 S *,5 R *,6 S *]‐3‐oxabicyclo[3.2.1]octane‐2,4‐dione‐6‐spiro‐3′‐(tetrahydrofuran‐ 2′,5′‐dione) [(−)‐DAn] via polycondensation with diamines and subsequent chemical or thermal imidization. The dianhydride (−)‐DAn was synthesized…
A theoretical approach is developed for reconstructing phonon dispersion in Si nanocrystals. It is found that for Si nanocrystals with size larger than 2 nm, smeared phonon dispersion could be established. The evolution of nanocrystal phonons into bulk ones is studied. Frequency shifts of bulk-like phonons versus nano…
Abstract Polarized Fourier transform infrared (FTIR) and ultraviolet‐visible (UV‐VIS) spectroscopy were used to investigate the photodegradation direction of polarized UV (PUV)‐irradiated polyimide (PI) films based on pyromellitic dianhydride (PMDA) and 4,4′‐oxydianiline (ODA). PI films strongly absorb below 350 nm, r…
We report here photoluminescence of CdS nanoparticles suspended in vacuum. The CdS nanoparticles, whose size distribution was bimodal having peaks at 11.3 and 43.1 nm, were produced by the gas-evaporation method and the nanoparticle beams were formed within the rarefied inert-gas flow. The band-edge emission and surfa…
Abstract Ultrafine carboxylated styrene–butadiene rubber(CSBR) powders were prepared by using gamma irradiation and following spray‐drying method. The influences of dose rate, absorbed dose, and sensitizer content on the crosslinking density of CSBR latices were studied in detail. Then the ultrafine CSBR powders were…
Abstract The regeneration of phenol‐saturated activated carbon in an electrochemical reactor was investigated in order to develop a novel regeneration method of activated carbon. The regeneration of spent activated carbon saturated with phenol was conducted in a stirred electrochemical reactor under different operatin…
The chemical bonding of hard and elastic amorphous carbon nitride $(a\ensuremath{-}{\mathrm{CN}}_{x})$ thin films was examined using solid-state ${}^{13}\mathrm{C}$ NMR spectroscopy. The films were deposited by DC magnetron sputtering in a pure nitrogen discharge on Si(001) substrates at 300 \ifmmode^\circ\else\textde…
Abstract To establish the optimum conditions for obtaining high molecular weight polyacetals by the self‐polyaddition of vinyl ethers with a hydroxyl group, we performed the polymerization of 4‐hydroxybutyl vinyl ether (CH 2 CHOCH 2 CH 2 CH 2 CH 2 OH) with various acidic catalysts [ p ‐toluene sulfonic acid monohy…
Abstract This article describes the results of the preparation and characterization of self‐doped conducting copolymers of aniline and toluidine with m ‐aminobenzene sulfonic acid. The copolymers have an intrinsic acid group that is capable of doping polyaniline. Spectroscopic, morphological, and electrical conductivi…
Abstract Poly(ethylene‐ co ‐vinyl alcohol) (EVOH) was used as a compatibilizer to make blends of low‐density polyethylene (LDPE) and plasticized starch (TS). The tensile properties and impact strength were measured and compared with those of neat LDPE. The morphology of the blend specimens, both fractured and unfractu…
Abstract Emulsion polymerization of methyl methacrylate (MMA) in the presence of chitosan was studied and a reaction mechanism was proposed. It was proved in the companion article that potassium persulfate (KPS) free radicals can degrade chitosan chains into chain free radicals. Therefore, it is possible to produce a…
The effect of shear flow on the structure and dynamics of monodisperse spherical polystyrene particles suspended at the interface between decane and water was observed. While undisturbed, the particles arrange themselves on a hexagonal lattice due to strong dipole-dipole repulsion resulting from ionizable sulfate grou…
Line tension for drops on spherical surfaces is approximately calculated and shown to depend on the contact angle and on the curvature of the spherical surface normalized with respect to the curvature of the drop. It is predicted that (a) the contact angle, at which the transition from positive to negative line tensio…
Abstract A redox initiator, cerium ammonium nitrate, was used to initiate the graft copolymerization of vinyl acetate (VAc) onto the chitosan chain in a dispersion polymerization at 60°C. With an addition of 0.5–7.5 g of chitosan based on 50 g of VAc, the monomer conversion was found to be between 70 and 80% after 2 h…
In particulate materials, such as emulsions and granular media, a "jammed" system results if particles are packed together so that all particles are touching their neighbours, provided the density is sufficiently high. This paper studies through experiment, theory and simulation, the forces that particles exert upon o…
Three ion-pair complexes, [RbzPy](+)[Ni(mnt)(2)](-) (mnt(2)(-) = maleonitriledithiolate; [RbzPy](+) = 4-R-benzylpyridinium; R = Br (1), Cl (2), and NO(2) (3)), with unusual magnetic properties have been synthesized and characterized. The crystal structures of 1 and 2 have been solved. The two complexes belong to the P…
Significant improvements in both the hydrothermal stability and the acidity of mesostructured aluminosilcates have been reported recently. New assembly pathways, along with post-synthesis treatment methods, have made it possible to form structures with thick and more highly crosslinked framework walls. The resulting s…
The results of a plane-wave pseudopotential study on the mechanical and electronic properties of twelve III–V zinc-blende (ZB) and wurtzite (WZ) semiconductors under pressure are presented. The lattice parameters, bulk moduli B 0 , energy band types, band-gaps E g Γ at the Γ point, and pressure dependences of E g Γ ar…
In this paper we report the existence of a giant magnetocaloric effect (MCE) in a intermetallic compound non-containing rare-earth. This effect is associated with the concomitant occurrence of a structural and a magnetic transition. The result has been compared with that obtained in a parent compound in which magnetic…