Materials Literature
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Abstract Chitosan membranes were first prepared by a thermally induced phase separation method and then alginate was coated on one side of the membranes by a modified dialysis apparatus to prepare alginate/chitosan membranes (A/C membranes). Electron spectroscopy for chemical analysis (ESCA), scanning electron microsc…
Abstract In this article we present the result of a comparative study of two kinds of polymerization methods—solution polymerization (sol. poly.) and dispersion polymerization (dis. poly.) for grafting polymer onto silica. As a model for the grafting polymerization reaction, styrene was chosen as the monomer and azo d…
Abstract A series of segmented polyurethanes (PUs) with novel thermosensitive shape‐memory behavior were synthesized via the in situ addition of a small amount of 1‐octadecanol (ODO) to a PU system. For comparison, liquid paraffin (LP) modified PUs were also synthesized. The effects of a small amount of ODO or LP on t…
Abstract Poly(vinyl alcohol) (PVA) can be dissolved in a nonaqueous medium in the presence of catalytic concentration of ethyl nitrate dimethyl sulfoxide, C 2 H 5 ONO 2 ·DMSO. From the PVA solution, poly(vinyl propionate), PVPR was prepared by the homogeneous esterification of PVA with propionic acid. The ester thus f…
Abstract Acrylic acid carboxylated acrylic rubber (ACM) and itaconic acid carboxylated acrylic rubber were prepared by 60 Co‐γ‐ray‐induced emulsion copolymerization. The polymers were characterized using FTIR and 13 C NMR spectroscopies. The acid value was determined with nonaqueous titration method. The molecular wei…
Abstract Poly(butylene terephthalate)/high density polyethylene (PBT/HDPE) blends and PBT/HDPE‐grafted maleic anhydride (PBT/HDPE‐ g ‐MAH) blends were prepared by the reactive extrusion approach, and the effect of blend compositions on the morphologies and properties of PBT/HDPE blends and PBT/HDPE‐ g ‐MAH blends was…
Abstract Recent studies on conducting polymers have demonstrated that polymers of 3‐substituted thiophene produce very stable compounds. Although this kind of substitution improves the regularity, structural defects still exist. To overcome this drawback, the polymerization of 3,4‐disubstituted thiophene is proposed a…
Abstract In the case of the electrically conductive master batch (ECMB) for fibers application, higher filler content required to produce adequate conductivity can be accompanied by a reduction in spinnability and mechanical property of final fibers. To minimize these problems, ECMB with the character of lower percola…
Hardfacing is one of the surfacing methods most widely employed in valve manufacturing industries to deposit Stellite 6, a cobalt based alloy, on low carbon steel valve seat rings to enhance specific properties such as wear and corrosion resistance. Gas tungsten arc welding (GTAW) process is used for hardfacing smalle…
Abstract We report the graft copolymerization of acrylic acid onto the polypropylene (PP) melt‐blown nonwovens induced by electron beam (EB) preirradiation in this article. The occurrence of the graft copolymerization was confirmed by means of XPS, FTIR, and SEM. The effects of preirradiation dose, monomer concentrati…
We consider a class of continuum models of epitaxial growth of thin films with two competing mechanisms: (1) the surface relaxation described by high-order gradients of the surface profile and (2) the Ehrlich–Schwoebel (ES) effect which is the asymmetry in the adatom attachment and detachment to and from atomic steps.…
Abstract Poly( p ‐dioxanone‐ co ‐ethyl ethylene phosphate)s were successfully synthesized by the ring‐opening copolymerization of p ‐dioxanone and ethyl ethylene phosphate with triisobutyl aluminum as an initiator; this was confirmed by 1 H‐NMR and infrared spectra. The effects of the reaction conditions, such as the…
Abstract In this article, we report a novel method for the design and development of a polyaniline (PANI)/poly(ethylene terephthalate) (PET) conducting composite fabric based on in situ polymerization. With the aim of improving fabric–PANI adhesion and good fastness to washing, we took some special steps: the alkali r…
Abstract Aqueous polyurethane dispersions derived from isophorone diisocyanate, various polycarbonatediols of different molecular weights, and dimethylol butyric acid were prepared by a dispersing procedure modified to enhance molecular weight. Particle size, average molecular weight, and tensile properties were deter…
Abstract Gyro‐chiral (G‐chiral) media of different constitutive relations are studied as potential materials to realize the negative‐index material (NIM). G‐chiral media are believed to have advantages over chiral media: negative refractive index and backward waves can be achieved without requiring the permittivity an…
Abstract Biodegradable foams were successfully prepared from calcium carbonate reinforced poly(propylene carbonate) (PPC/CaCO 3 ) composites using chemical foaming agents. The incorporation of inexpensive CaCO 3 into PPC provided a practical way to produce completely biodegradable and cost‐competitive composite foams…
Abstract The thermal degradation of three poly(ester amide)s derived from glycolic acid and different ω‐amino acids is studied by thermogravimetric analysis (TGA) at different heating rates and the results are compared. Thermal decomposition follows a two‐step reaction, the mechanism involved in each step being possib…
Resistivity, thermopower, Hall coefficient, and magnetization are measured for a set of polycrystalline samples of the room-temperature ferromagnet Sr 1- x Y x CoO 3-δ up to 800 K. A peculiar metallic state accompanied by a large effective magnetic moment of 3.40 µ B /Co is observed above 600 K, indicating that electr…
Abstract A study is presented on the directivity of grounded low‐permittivity metamaterial slab structures that achieve highly directive broadside radiation. Two‐dimensional (2D) configurations excited by electric line sources are considered, adopting a scalar plasma‐like dispersive permittivity for the metamaterial m…
Abstract The problem of an arbitrarily located electric line source radiating in the presence of a metamaterial‐coated cylinder is solved analytically and implemented numerically. Electrically small resonant metamaterial‐coated cylinders are designed that lead to significant enhancements of both the radiated and scatt…