摘要:

AbstractIn order to improve dimension stability and toughness of melamine formaldehyde moulding materials (MF), compatible bisphenol A epoxy resins (EP) with additional methylol groups were synthesized and characterized. Crosslinking of those epoxyresol resins with 2‐ethyl‐4‐methylimidazole in the presence of MF resin was investigated. Transfer‐moulded specimens revealed a two‐phase morphology in which the EP phase is used as a host for modification with carboxylic functionalized oligomeric NBR rubber (CTBNX), which is not effective in MF moulding materials alone. The addition of 0.5 – 4 wt.‐% CTBNX to the MF moulding materials at an epoxy content of maximum 20 wt.‐% results in 50–100 % increase of elasticity and toughness without serious decrease in stiffness and heat deflection temperature, provided that covalent interfacial bonds exist. In addition, the post‐shrinkage of MF parts decreases if a moderate EP/CTBNX co

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370101

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe formation, morphology and transport properties of a new multilayer pervaporation membrane have been studied.This membrane consists of a microporous support based on a poly(amideimide), an intermediate poly[2‐(N,N‐dimethylamino)ethyl methacrylate] layer, and a top diffusion layer of ladder polysiloxane. The membrane has low permeability for weakly polar liquids (e.g. cyclohexane); it exhibits dehydrating properties for waterisopropanol mixtures and has high productivity (up to 14.5 kg h‐1m‐2) and high separation factor (up to 27430) when methanol is isolated from mixtures with cyclohexane. The transport properties of the membrane are discussed with respect to the Henis‐Tripodi resistance model, taking into account the hydrophobic‐hydrophilic nature of the po

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370102

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractLow‐molecular‐weight stat‐poly(ethylene oxide‐co‐propylene oxide) polymers have been prepared anionically using a new heterogeneous catalytic process previously reported. They were fully characterized by1H and13C NMR spectroscopy in order to determine the distribution of the ethylene oxide (EO)‐centered triads, as well as the average lengths of poly(ethylene oxide) (PEO) sequences. Low degrees of crystallization were determined by DSC. These copolymers have been successfully used for applications in the solid polymer electrolytes field and high levels of conductivity at room temperature have been measured. The results are in good agreement with those obtained from a Monte Carlo simulation method using the copolymerization terminal model developed for radical pol

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370103

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe thermo and radiooxidation of a poly(ethylene‐co‐methyl acrylate)‐based industrial elastomer has been studied by various techniques. As already shown in the case of thermooxidation, these elastomers lead to crosslinking reactions when submitted to γ irradiation in air. Considering that the thermooxidation rate follows an Arrhenius law, and that the radiooxidation rate is directly proportional to the dose rate, the predominant mechanism (thermooxidation or radiooxidation) can be defined, as a function of aging conditions. This method was successful for two different aging cond

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370104

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe preparation of single‐phase inverse microemulsions of toluene/sodium bis(2‐ethylhexyl)sulfosuccinate (AOT)/water/acrylamide (AAm) is described and their properties prior to polymerization (macro and microviscosity as a function of volume fraction Φawof the dispersed aqueous (water + acrylamide) phase, of the [to‐luene]/[AOT]molar ratio and of the acrylamide/water mass ratio) were studied.The polymerization of acrylamide in dispersion systems was initiated by the oilsoluble initiator dibenzoyl peroxide at 60°C. The polymerization rate of acrylamide for a given [toluene]/[AOT]molar ratio and AAm/water mass ratio monotonically decreases beyond a Φawvalue of 20%. The polymer particle size in polymerized systems as well as the molecular mass of polymer in the polymer particles increase on increasing the acrylamide concentration in the aqueous phase and/or the Φawvalues of the dispersion system. On increasing the surfactant AOT concentration both polymer particle size and polymer molecular mass decrease for a given set of other relevant parameters of the dispersion system (i.e. [toluene]/[AOT]and AAm/water ratios). The polymerized inverse dispersion system can be converted to an oil‐in‐water dispersion by addi

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370105

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe preparation of single‐phase toluene/sodium bis(2‐ethylhexyl)sulfosuccinate(AOT)/water/acrylamide/sodium dodecyl sulfate(SDS) inverse microemulsions is described and their properties prior to polymerization (macroviscosity as a function of volume fraction Φawof the dispersed aqueous (water + acrylamide(AAm) + SDS) phase, and of SDS/AAm mass ratio) are studied. At 20°C three viscosity maxima are observed. At 50°C all three peaks remain, the viscosity of the first and third peak, respectively, is lowered to 5–8 mPa· s while the second, most prominent peak still marks the level of ca. 250 mPa· s. The polymerization of acrylamide in dispersion systems is initiated by water‐soluble ammonium peroxodisulfate (APS) and oilsoluble dibenzoyl peroxide (DBP) at 60°C. The polymerization rate of acrylamide for a given [toluene]/[AOT]molar ratio and AAm/water mass ratio monotonically decreases for Φawvalues greater than 20%. The polyacrylamide viscosity molecular mass increases up to a Φawvalue of ca. 30%, irrespective of the nature of initiator. For Φawvalues over 30% the viscosity molecular mass of polyacrylamide seems to level off with some sings of shallow minimum cl

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370106

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe effect of the polymerization conditions on the properties of poly(ϵ‐caprolactam)‐polybutadiene block copolymers prepared by polymerization casting through anionic polymerization of ϵ‐caprolactam initiated with potassium salt of ϵ‐caprolactam in the presence of α,ω‐dihydroxy‐polybutadiene and isocyanates or their blocked derivatives as functionalizing agents was investigated.The influence of the content of telechelic polybutadiene, its molecular weight, type of diisocyanate, and polymerization temperature on the fundamental mechanical properties of the prepared materials and on the polymerization ra

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370107

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractMacroporous glycidyl methacrylate (GMA)‐divinylbenzene (DVB) copolymer beads have been synthesized and the adsorption of bilirubin, albumin and other serum components were studied. The beads composed of DVB/GMA in the weight ratio of 75/25 provide an excellent bilirubin adsorption ability. When the surface of the beads was previously coated with albumin, discriminating adsorption of the bilirubin in the serum was attained and the adsorption of albumin was depressed. In addition, when the coated albumin was crosslinked with glutaraldehyde, the excellent bilirubin adsorption ability was maintained, however, an adsorption of albumin from the serum occurre

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370108

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe photoinitiated free‐radical polymerization of methyl methacrylate (MMA) and the radical‐promoted cationic polymerization of cyclohexene oxide (CHO) in the presence of low‐molecular‐weight polyepichlorohydrin terminated with groups containing benzoin derivatives were studied. Benzoin‐terminated polyepichlorohydrin was prepared by Activated Monomer (AM) polymerization. Upon photolysis. polymer‐bound alkoxy benzyl radicals were generated, initiating the radical polymerization of MMA. In the case of radical‐promoted cationic polymerization of CHO, the cationic initiating species were formed by the oxidation of photochemically generated polymeric radicals by N‐ethoxy‐2‐methylpyridinium

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370109

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractTwo naphthalene‐aromatic polyamides were prepared from 2,6‐naphthalenedicarboxylic acid and various aromatic diamines by a modified Higashi phosphorylation reaction. The first polymer, poly(4,4′‐diaminobenzanilide‐2,6‐naphthalamide)**(DBNA), was synthesized by the reaction of 2,6‐naphthalenedicarboxylic acid with 4,4′‐diaminobenzanilide. The second polymer, 50/50 copoly(1,4‐phenylene/1,4‐bis(4′‐phenoxy)benzene‐2,6‐naphthalamide)***(PBNA), is a copolymer synthesized using an equimolar ratio of 1,4‐phenylene diamine and 1,4‐bis(4′‐aminophenoxy)benzene. These two polymers have inherent viscosities of 4.17 and 2.32 dL g‐1, respectively, and dissolve in N‐methyl‐2‐pyrrolidone (NMP)containing LiCl. Highstrength films were obtained by casting from these polymer solutions. Blends of DBNA/amorphous nylon and of PBNA/amorphous nylon were prepared by rapidly precipitating the ternary NMP solution into deionized water, and hot‐pressing to films at 185°C. The compatibility, morphology, and mechanical properties were investigated by dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and tensile tests. The results revealed that both DBNA and PBNA were partially compatible with amorphous nylon. DBNA formed microfibrils in the amorphous nylon matrix, and its mechanical properties, tensile strength and modulus, improved with increasing DBNA content. PBNA had no reinforcing effect, perhaps because it did not

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052370110

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY