摘要:

AbstractAsbestos fibers, of the chrysotile variety, were coated with a thin polyamide film by an in situ polycondensation technique. Ionomer‐based composites were prepared containing the so‐modified asbestos fibers in a random in‐plane orientation; results of testing the tensile properties of these asbestos/polyamide/ionomer composites are presented. Parameters investigated comprise the asbestos content in the composite and the polyamide content deposited on asbestos. A significant improvement in the tensile performance was established, especially at the intermediate polyamide content of 3.4 phr. The behavior is discussed in terms of possible interactions between the phases present in the composite mat

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030701

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractFour new bisdienes were prepared from 2‐bromomethyl‐1,3‐butadiene and N,N‐diethyl benzidine; bis[4‐(N‐ethyl) aminophenyl]‐p‐diisopropylbenzene, 1,4‐diamino‐2,3,5,6‐tetramethylbenzene and α,α′ bis(4‐amino‐3,5‐dimethyl phenyl)‐p‐diisopropyl benzene. Polyimides were synthesized by the Diels–Alder reaction of these bisdienes and bis(4‐maleimidylphenyl)methane and bis(3‐maleimidylphenyl) sulfone. The polymers were soluble inm‐cresol, dimethyl sulfoxide and chlorinated hydrocarbon solvents. Moderate thermal stability was observed by the

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030702

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractBinary blends of poly(ethylene terephtalate) (PET) and thermotropic liquid crystal polyester (TLCP) have been prepared by both solution and melt blending methods. The TLCPs utilized were Vectra (Hoechst Celanese), TR‐4, a TLCP synthesized in our laboratory, and a block copolymer consisting of three TR‐4 units followed by three PET units. The phase behavior of the blends was studied by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and optical microscopy. The results show that none of the blends is miscible, but significant interactions exist between the PET phase and the TLCP phase in the case of TR‐4 and TR‐4 block copolymer blends. These interactions lead to a different nucleation mechanism in these blends compared to that in PET

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030703

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA carbonyl hemoglobin (HbCO) solution was stirred with a mixed powder of polymerizable 1,2‐bis(2,4‐octadecadienoyl)‐sn‐glycero‐3‐phosphocholine (DODPC), cholesterol and stearic acid (7/7/2 by mol). The mixture was extruded through polycarbonate membrane filters (final pore size = 0.2 μm Ø). The average diameter of the resulting vesicles was 203 ± 39 nm. The [Hb]/[Lipid]ratio (the weight ratio of Hb in vesicle to lipid) increased with the Hb concentration, and decreased with the NaCl concentration. A maximum [Hb]/[lipid]ratio was observed at pH 6.9, which was the same as the isoelectric point of Hb. The vesicles were stabilized by γ‐irradiation (60Co) because the bilayer lipids bound each other to yield polyphospholipids. Denaturation of Hb by γ‐irradiation was not detected. These polyphospholipid vesicles encapsulating Hb were stable even against the freeze–thaw cycles and the f

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030704

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractElectropolymerization of pyrrole on tantalum (Ta) electrodes was carried out in buffer solutions (0.04 M phosphoric acid, 0.04 M acetic acid, 0.04 M boric acid and 0.2 M sodium hydroxide) containing 0.1 M sodium ptoluenesulfonate (TsONa) under galvanostatic conditions and it was found that a polypyrrole (PPy) and a tantalum oxide (Ta2O5) layer are formed on a Ta electrode by an electrochemical oxidation process. The conditions of this simultaneous formation were studied in respect to current density (id), pyrrole concentration ([Py]), pH and the amount of electricity. Under certain conditions ([Py]= 0.25 M, pH = 1.8, id= 10–20 mA cm−2, the amount of electricity = 1 C), 6–8 μm thick PPy films were efficiently formed on homogeneous 30–50 nm thick Ta2O5layers. The PPy film showed a high electrical conductivity (110 s cm−1), adhered well and covered the Ta2O5layer. The resulting PPy/Ta2O5/Ta system is therefore proved to have excellent properties as a

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030705

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe electrophilic reaction of sulfur dichloride with diphenyl sulfide proceeds efficiently at room temperature to yield oligo(phenylene sulfide) in the presence of a catalytic amount of Fe powder. Sulfur dichloride shows higher reactivity than sulfur monochloride. The reaction is promoted through the activation of sulfur dichloride by Fe powder. The polymeric product contains a linear structure linked by disulfide and sulfide bonds.

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030706

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe curing behavior of unsaturated polyester resin was investigated. In the present study, styrene, methyl ethyl keton peroxide (MEKP) and cobalt octoate (CO) have been selected as solvent (monomer), catalyst and accelerator, respectively. The effect of the concentration of both MEKP and CO on the curing exotherm, curing time, hardness and compressive strength of the prepared copolymers was investigated.

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030707

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA new approach for design of improved interfacial bonding between carbon fibers and polymeric matrices is described. In this method the affinity of surface‐treated carbon fibers to various polymer matrices is simulated by analyzing the adsorption characteristics of model compounds, typical of the polymer units, onto very high surface area carbon fibers. The affinity can be evaluated by the use of Thermogravimetric Analysis (TGA) to measure adsorption–desorption characteristics. Since high surface area, activated carbon fibers (ACF) can be chemically treated to obtain acidic, basic, nonpolar or highly polar surfaces, it should be possible to assess the interactions of chemically modified surfaces with model compounds such as methanol (MeOH), acetone, dimethylformamide (DMF), dimethylether, tetrahydrofuran (THF) and water. Some preliminary results are presented, indicating that surface treatments for carbon fibers other than oxidation may lead to enhanced bonding with polymeric matri

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030708

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY