摘要:

AbstractChitosan, [(1,4)‐2‐amino‐2‐deoxy‐β‐D‐glucan], was reacted consecutively with epichlorohydrin and thiourea. Subsequent hydrolysis of the isothiouronium salt yielded the mercaptan derivative of chitosan, which scavenges mercury ions from solution in the presence of a considerably high concentration of chloride ions.Sulfur contents varied with reacting conditions and reached values up to 7.3%. The derivative is insoluble due to partial crosslinking of chitosan during the reaction with epichlorohydrin and was characterized by IR spectroscopy, solid‐state13C NMR, thermal analysis and pyrolysis

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070101

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractA phenomenological model has been proposed to understand the development of strong anisotropy in physical properties of semicrystalline polymers on uniaxial drawing. The proposed model introduces temperature as an explicit parameter in the orientation function. The model contains two free parameters for each polymer which can be evaluated by fitting the experimental data on birefringence versus draw ratio at a particular temperature. The calculated values of elastic moduli, thermal conductivity and expansibility along and perpendicular to the drawing direction over the entire range of draw ratio and a wide range of temperature are in good agreement with experimental values.

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070102

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractFasern aus Poly(acrylnitril‐co‐methylacrylat‐co‐itaconsäure) wurden unter unterschiedlichen Bedingungen verstreckt. Die verstreckten Fasern wurden bezüglich des allgemeinen Orientierungsgrads und des Orientierungsgrads und Anteils der parakristallinen Gebiete charakterisiert; mechanische Kennwerte der Fasern wurden gemessen. Aus der Korrelation der erhaltenen Werte mit der sogenannten Kompensationsspannung der Fasern wird geschlossen, daß letztere ein Maß für die Eigenspannungen in den Fasern darstellt und eine Optimierung der Herstellung und Weiterverarbeitung der Faser

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070103

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractReaction products of soluble chloromethylated polystyrene with diethylamine, poly(styrene‐co‐chloromethylstyrene) with diethanolamine, and poly(styrene‐co‐glycidyl methacrylate) with diethanolamine were prepared and supported on activated alumina granules. A study was made of removal of Escherichia coli cells from water by these supported alumina granules. When these granules (0.100 g) were stirred in a viable cell suspension (107–8cells/ml, 20 ml), the viable cell number decreased by the adsorption of the cells to the granules. The adsorption attained approximately to the equilibrium (saturated adsorption) after about 2 h from the start of the adsorption. The decrease coefficient (D, which corresponds to the adsorption rate constant) was determined from the decrease in the viable cell number in the adsorption for about 2 h from

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070104

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractRadical polymerizations of mono‐ and di‐methacrylic esters containing bisphenol‐S (BPS‐M and BPS‐DM) were studied in terms of polymerization rate, solvent effect, copolymerization and kinetic measurements of photocrosslinking. The solvents were found to affect significantly the polymerization rate. Polar solvents such as DMSO and acetonitrile were found to slow down the polymerization rate. Copolymerization of BPS‐M(M1) with MMA(M2) was studied in acetone at 60°C. The monomer reactivity ratios were calculated to be r1= 3.72 ± 0.01 and r2= 0.80 ± 0.01 by the Fineman‐Ross method. The high reactivity of BPS‐M observed in this copolymerization system may be due to the “matrix effect”. Functional polymers containing methacrylate side‐groups were successfully modified and photocrosslinked by irradiation in the presence of benzoin isopropyl ether. The photocrosslinking process is found to be

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070105

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractReaction of chlorosilanes (Me3SiCl, R2SiCl2, SiCl4; RMe, Ph) with MgCl2· 6 H2O were investigated for the efficiency of removal of water. The nature of chlorosilane is found to govern the rate of dehydration. The treatment of hydrated magnesium chloride with dichlorodiphenylsilane gives unsolvated anhydrous magnesium chloride in high yields. Anhydrous MgCl2is used as support for the preparation of titanium catalyst. The catalyst in conjunction with Et3Al and Ph2Si(OMe)2as cocatalyst system shows high activity for propylene polymerizati

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070106

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe synthesis of new, unsymmetrically functionalized azo compounds and their incorporation into polymers is described. Their photochemical decomposition and thermal stability was studied by UV spectroscopy and differential scanning calorimetry (DSC), respectively. Chemical degradation was followed by viscosity measurements.

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070107

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractPhotosensitive microcapsules, which are thermally quite stable, are formed via interfacial polycondensation in which one of the shell‐forming reactants contains an azo function.An azo monomer, containing α,ω‐carboxylic diacid dichloride was reacted with a trifunctional aliphatic amine on the oil‐water interface resulting in a shell‐forming crosslinked polyamide. The size of the resulting photosensitive microcapsules was determined. It could be shown that these microcapsules can be opened by means of

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070108

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractOxime‐blocked toluene diisocyanates were synthesized and characterized by infrared spectra, nuclear magnetic resonance spectra, elemental analysis etc. Thermal analyses of blocked isocyanates were done by thermogravimetry. Solubility of blocked isocyanates in various polyols was tested. Formation of isocyanate on heating the blocked isocyanate was identified by gas chromatographic analysi

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070109

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractUrease enzyme was immobilized in hydrogels prepared from vinyl pyrrolidone/water/crosslinking agent ternary mixtures by γ‐irradiation of the solutions at room temperature. Two types of crosslinking agents used, namely ethylene glycol dimethacrylate and trimethylol propane triacrylate, yielded hydrogels with different swelling and crosslink density properties. The activity of immobilized urease was measured at the optimum conditions of temperature and pH over a period of time. It has been determined that for hydrogels with average molecular weights between crosslinks, Mc, above 2000, urease leakage is a serious problem. When Mcis around and below this value, immobilized systems showed a long time activi

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052070110

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY