摘要:

AbstractThe synthesis of new segmented polyurethanes containing different amounts of N,N‐diethylaminoethyl‐N′‐2,2 hydroxymethylpropionamide, and able to bind, after suitable quaternization, high amounts of heparin, is described. The quaternization is carried out on organic solutions of the polymers. Polymers have been characterized by spectroscopic techniques (transmission and reflectance IR and1H and13C NMR), molecular weight measurements and differential scanning calorimetry. The heparin content of the polymer films was determined by a colorimetric system, and its biological activity was evaluatedin vitroby activated partial thromboplastin time (APTT) measurements. The distribution of heparin on the surface and in bulk of the heparinized films was evaluated by scanning electron microscopy (SEM) combined with X‐ray energy dispersive spe

ISSN:1042-7147    

DOI:10.1002/pat.1993.220040501

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA tantalum electrode on which polypyrrole (PPy) had been previously formed by electropolymerization was galvanostatically electrolyzed in an aqueous solution of 0.01 wt% phosphoric acid. This process contains the irreversible oxidation of a PPy film, the decomposition of solvent, and the formation of Ta2O5by the reaction of OH−coming through the PPy film, with Ta electrodes. A three layer‐structure (PPy/Ta2O5/Ta) was confirmed by electron spectroscopy for chemical analysis (ESCA). A PPy film containing CIO4−as dopant [PPy(CIO4−)] was significantly deteriorated in comparison with PPy(TsO−) at the electrolysis. Therefore, the (PPy(TsO−)/Ta2O5/Ta) system showed better electrical characteristics as a capacitor than the (PPy(CIO4−)/Ta2O5/Ta) system showed better electrical characteristics as a capacitor than the (PPy(ClO4−)/T

ISSN:1042-7147    

DOI:10.1002/pat.1993.220040502

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA method is described to impart flexibility and mechanical strength to conducting polyaniline by polymerizing aniline on fabrics and on cellulose papers. The study indicates that these conducting fabrics offer 16–18 dB of shielding effectiveness for the control of electromagnetic interference (EMI) up to a frequency of 103MH

ISSN:1042-7147    

DOI:10.1002/pat.1993.220040503

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe radiation‐induced crosslinking and grafting of two aryloxy‐substituted elastomeric polyphosphazenes have been carried out by both gamma and electron beam irradiation. The classic Charlesby–Pinner [1] plus a simpler approach were used to determine the G(X) values for the crosslinked elastomeric polymers. The apparent G(X) value for the same polymer depended on whether the gamma‐ray or the E‐beam results were used. The presence of 8.5% repeat units with allylic groups in the side chain increased the G(X) value by an order of magnitude when the irradiation was performed under vacuum with the gamma source. The extent of acrylic acid grafting was also higher for the polymer containing the allylic group. Nearly all the grafted polyphosphazene films were insoluble in THF, a good solvent for the ungrafte

ISSN:1042-7147    

DOI:10.1002/pat.1993.220040504

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractLow molecular weight liquid rubber (ATBN = amine terminated butadiene acrylonitrile copolymer or CTBN = carboxyl terminated butadiene acrylonitrile copolymer)–DGEBA (diglycidyl ether of bisphenol A) blends indicated upper critical solution temperature (UCST) behavior. The phase separation behavior of the neat and crosslinked rubber (ATBN, CTBN)–epoxy blends was analyzed by a laser light scattering experiment. Lauryl peroxide (LPO) was employed to crosslink the rubber during the initial annealing stage. The onset point of the phase separation in the crosslinked ATBN–epoxy system occurred later than in the case of the neat ATBN–epoxy system. However, the onset point of the phase separation process started earlier in the case of the crosslinked CTBN–epoxy system. The domain correlation length of the crosslinked rubber‐added system was smaller than that of the neat rubber

ISSN:1042-7147    

DOI:10.1002/pat.1993.220040505

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractAqueous foaming solutions of permethylsiloxane surfactants and fluorocarbon surfactants are very resistant to antifoaming. Newly developed polysiloxane fluids having highly fluorinated chains showed very low surface tensions and were examined as antifoaming compounds to test against these two classes of surfactant systems. The fluorinated polysiloxanes evaluated were poly‐[(3,3,4,4,5,5,6,6,6 ‐ nonafluorohexyl)methylsiloxane] (PNFHMS), and 1H,1H,2H,2H‐perfluorodecyl‐terminated polydimethylsiloxane (Def‐DMS). Poly(dimethylsiloxane) (PDMS) was also studied as a standard siloxane polymer fluid for comparison. The antifoams composed of PNFHMS and Def‐DMS polymer fluids incorporated with silica showed effective antifoaming against the low surface tension aqueous solutions of representative permethylsiloxane and fluorocarbon

ISSN:1042-7147    

DOI:10.1002/pat.1993.220040506

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY