摘要:

AbstractNovel epoxy resins containing chromium acrylate have been synthesized by reacting chromium acrylate with bisphenol‐A and excess epichlorohydrin. The quantities such as epoxy equivalent weight, hydroxy content, hydrolyzable chlorine content and viscosity have been determined. The resins have been characterized by IR and1H NMR spectroscopy. The cured resins were evaluated for thermal properties. The curing of resins was carried out with Ciba Geigy HY 850 (aliphatic amine adduct) at 30°C for 24 h. The cured resins have excellent thermal and chemical resistance, in addition to an excellent electrical conductivity. The reaction follows first order kinetics with an activation energy of 47 kJ mol−1and 34 kJ mol−1in the presence and absence of chromium acrylate, respectively. The chromium forms a complex with bisphenol‐A, as indicated by spectroscopic studies, which increases epo

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190101

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractFür den Einsatz biologisch abbaubarer Kunststoffe in der pharmazeutischen Industrie und Medizintechnik wurden Produkte verschiedener Hersteller, wie Biopol, Biocellat und Mater‐Bi untersucht. Dabei zeigte vor allem Biopol das notwendige Anforderungsprofil, d.h. die Anwendbarkeit aller Sterilisationsverfahren ohne Festigkeitsbzw. Steifigkeitsverluste sowie Temperatur‐ und Alkoholbeständigkeit. Dagegen wiesen die Werkstoffe Mater‐Bi und Biocellat einige Schwachstellen auf. Bei Mater‐Bi lagen diese bei der Wasserdampfsterilisation sowie bei der geringen thermischen und Medienbeständigkeit. Biocellat versprödet dagegen durch die erhöhte Temperatur bei der Dampfsterilisation, d.h. daß ein Einsatz über 60°C nic

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190102

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractPoly[(2,4‐dichloro‐6‐ethoxy‐s‐triazine)‐alt‐(bisphenol A)] (T‐BPA), a polymer with interesting mechanical and thermal properties, was synthesized by phase transfer catalysed interfacial polycondensation. The reaction conditions for the synthesis of T‐BPA were investigated and optimized. The influence of several reaction parameters, such as temperature, reaction time, type and concentration of phase transfer catalyst, concentration of monomers, type of solvent, type of base, salt addition, and molecular weight terminator concentration on the reduced specific viscosity and yield of T‐BPA was investigated. As a result, it is possible to synthesize T‐BPA at reaction conditions being favourable with regard to the costs of

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190103

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractA series of hydrophilic‐hydrophobic poly(vinyl cinnamate) (PVCin) membranes was developed. The poly(vinyl cinnamate)s were synthesized from poly(vinyl alcohol) with various amounts of cinnamoyl chloride in the presence of alkali. The amphiphilic membranes, which can be used instead of the traditional two‐layer membranes in the enzyme electrode, were prepared by using photosensitive poly(vinyl cinnamate) and/or poly(vinyl alcohol) with sensitizers. The properties of photocrosslinking, water permeability and oxygen permeability of the amphiphilic membranes were investigated. The combinations of amphiphilic membranes were examined by scanning electron microscopy (S

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190104

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractA UV‐curable acrylated urethane prepolymer was synthesized from tolylene‐2,4‐diisocyanate (TDI), a polyether polyol (Arcol 1131) and endcapped with 2‐hydroxyethyl methacrylate (HEMA) by addition reaction in the presence of dibutyltin dilaurate as catalyst. UV curing was performed with either diethylene glycol diacrylate or thiodiethylene glycol diacrylate as reactive diluent.The effects of reactive diluent types, their concentrations and the humidity of environment on mechanical properties of cured films were investigated. Changes in the tensile strength, elongation and Young's modulus values of the cured films upon addition of reactive diluents with different concentrations were related to the effect of the diluent on the crosslinking density of cured films.The increase of relative humidity from 50 to 95% caused a decrease of tensile strength and Young's modulus values of cured films. It is proposed that the decrease of these physical properties in high relative humidity is due to the formation of hydrogen bonding in polymer chains caused by water mo

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190105

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractInterpenetrating polymer networks (IPNs) of polyurethane based on hydroxyterminated natural rubber with varying NCO/OH ratios and polystyrene were synthesized under different experimental conditions. These IPNs were found to make tough films. The IPNs were characterized by their physical, mechanical and morphological properties like density, Shore‐A hardness, crosslink density, tensile strength and elongation at break. The IPNs exhibited an increasing trend in density, Shore‐A hardness and tensile strength with increasing polystyrene content, while elongation at break decreased with similar variation in polystyrene content. The crosslink density measurements indicated a possible phase inversion proc

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190106

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractInteraction of polyacrylonitrile with sodium azide and ammonium chloride leading to the formation of poly(5‐vinyl tetrazole) has been studied in detail. The reaction is found to proceed to high conversion extents (up to 94–94.5%) and allows to obtain polymeric products with a wide range of poly(5‐vinyl‐tetrazole) content. Comparative studies of the structures and properties of the obtained polymers and 5‐vinyl tetrazole homopolymer as well as copolymers of 5‐vinyl tetrazole with acrylonitrile have been carried out using IR,13C NMR and complex thermal an

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190107

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractAlkylation of poly(5‐vinyl tetrazole) with dimethyl sulfate and tert‐butyl alcohol as well as with alkyl halides RHal (RCH3, C2H5, CH2CHCH2, n‐C4H9, t‐C4H9) has been studied under various conditions in order to develop a new method of synthesis of tetrazole‐containing polymers having a complex of valuable properties. The kinetic study of the process and comparison of isomeric compositions and spectroscopic characteristics (IR,1H NMR and13C NMR) of poly(N‐alkyl‐5‐vinyl tetrazole)s synthesized by alkylation of poly(5‐vinyl tetrazole) and of those prepared by (co)polymerization of the corresponding vinyl tetrazoles have been carried out. The alkylation is found to proceed to high conversion extents (up to 99.8%) and enables to obtain a wide variety of polymeric products having the composition, structure and properties very similar to those

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190108

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractA study of the immobilization of glucose oxidase on a poly(vinyl alcohol) (PVAL) membrane in the presence of UV sensitizers was carried out. Enzyme membranes were prepared from PVAL‐diazoresin and PVAL‐sensitizer systems, crosslinked by means of UV irradiation. An effective enzyme electrode was developed by using the immobilized glucose oxidase membrane, and its characteristics were investigated. The effects of the concentration of sensitizers in poly(vinyl alcohol) and UV irradiation time on the degree of insolubility as well as the activity yield of the membrane were examined for the immobilized glucose oxidase using glucose as a substrate. Temperature and pH dependences of the relative activity, stability in repeated use, storage stability and calibration plots of the enzyme membranes were evaluated. The unstability phenomenon, found in the initial use of the immobilized glucose oxidase membrane, which was prepared from PVAL‐sensitizer system, was also investi

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190109

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effect of plasma treatment of polyethylene ultrafiltration membranes on fouling and cleaning phenomena during filtration of bovine serum albumin solutions is discussed. Air‐plasma of 2.45 GHz raises the membrane surface hydrophilicity from 0 up to 60%. The flux is maintained at 90–99%. Plasma‐treated membranes are easier to clean than untreated polyethylene membranes. Despite that, the plasma‐modified membranes are susceptible to more intensive deposition of

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052190110

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY