摘要:

AbstractGraft copolymers of vinyl chloride onto poly(butylacrylate) with alternating amount of diallylphthalate crosslinker (PBA‐g‐VC) have been synthesized by suspension polymerization. Taking into account different crosslinking density of PBA, the processing behaviour of PBA‐g‐VC was studied with a Brabender Plasticorder and a viscoelastometer. The experimental results showed that, with increasing crosslinking density of PBA, the processing behaviour of PBA‐g‐VC improved initially, then reached an optimum and finally declined with further increase in crosslinking density of the backbone. Based on the results of viscoelastometer measurement, the mechanism of change of processibility of graft copolymer i

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090101

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractPoly(tetrafluoroethylene) powder has been treated with sodium‐naphthalene complex in tetrahydrofuran (THF) to improve its surface properties. The cryocondition (−40°C) was taken to keep the active species alive so that the PTFE powder surface could be etched homogeneously and a large area of PTFE could be etched. The Na‐treated PTFE powder was examined by IR, ESCA (electron spectroscopy for chemical analysis), X‐ray diffractometry, thermal analysis and SEM (scanning electron microscopy). IR spectra showed that the surface structure of Na‐treated PTFE powder possessed a lot of CFCF− double bond structures. ESCA surface analyses also revealed the formation of CFCF− double bonds. During the process of sodiumnaphthalene complex etching, most of NaF salt formed was adsorbed on the surface of treated PTFE (CPTFE, NaF adsorbed) and a small amount of NaF salt was found doped into treated PTFE. As a result, part of the surface of treated PTFE was found doped into treated PTFE. As a result, part of the surface of treated PTFE was similar to a free alkali‐fluoride‐doped polyfluoroacetylene. It was shown by SEM that the etched P

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090102

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractA new copolymer, poly(maleimide‐alt‐trimethylvinylsilane) (PMVS), with a high silicon content was synthesized by free‐radical copolymerization, in order to obtain a positive photoresist containing diazonaphthoquinone sulfonate as a dissolution inhibitor. PMVS shows a high etching selectivity of 1 : 16 compared to a commercially available, hard‐baked photoresist (HPR‐204). In addition, the rigid cyclic maleimide group is responsible for high temperature

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090103

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper describes the effect of ethyl methacrylate (EMA) on the thermal and mechanical properties of glass fibre‐reinforced laminates of vinyl ester resins derived from diglycidyl ether of bisphenol‐A and methacrylic acid. The thermal stability and the curing characteristic of the resins were investigated by thermogravimetric analysis and differential scanning calorimetry. The glass transition temperature of the laminates decreased with increase in EMA content. Dilution of vinyl ester resin with EMA resulted in a decrease in flexural strength and flexural modulus of the lamina

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090104

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractPermeation and separation characteristics for the feed vapours from aqueous alcoholic solutions through chitosan derivative membranes such as chitosan acetate (GA‐ChitoA), chitosan (GA‐Chito), and carboxymethyl chitosan acetate (GA‐CM‐ChitoA) membrane crosslinked with glutaraldehyde were investigated by evapomeation. The GA‐Chito and GA‐CM‐ChitoA membranes prepared from casting solutions containing an optimum amount of glutaraldehyde showed a high permeation rate and high water permselectivity for an azeotropic composition in an aqueous ethanol solution. The permselectivity for water through the GA‐CM‐ChitoA membrane in evapomeation was in the order of aqueous solutions of methanol

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090105

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

Abstractα,ω‐Diglycidyl‐oligoethylenoxides were prepared by reacting α,ω‐dihydroxy‐oligoethylenoxides with epichlorohydrin. They were then crosslinked with triethylenetetramine to form catalyst beads which were tested for their liquid‐solid phase‐transfer catalyst activity in the reaction of 1‐bromobutane with potassium phenoxide. Regardless of the oxyethylene chain length, the catalyst beads showed significant activity, which was relatively high for oligomers with a great number of oxyethylen

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090106

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

Abstract2,2‐Bis[4‐(2‐hydroxy‐3‐methacryloyloxy‐propoxy)phenyl]propane (Bis‐GMA) was used as the main ingredient for a dental composite. The dental composite was prepared by mixing high viscosity Bis‐GMA with a low‐viscosity diluent monomer. Three monomers were used: triethylene glycol dimethacrylate (TEGDMA), trimethylol propane trimethacrylate (TMPTMA), and trimethylol propane triacrylate (TMPTA). The mixed components were allowed to polymerize under visible light. The degree of conversion was higher for the sample with lower viscosity. The silica which was used as filler in the dental composite was modified by using the radiation‐induced polymerization method in which methyl methacrylate (MMA) was grafted onto the silica gel. The higher the content of PMMA in the modified filler, the lower the hardness of the composite. Most properties of the samples are the same as those of a commercial product. The compressive strength is higher due to the strong filler‐matrix interface which is provided b

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090107

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe emulsification and electrodeposition properties of mixtures of a poly(oxypropylene) (POP)‐modified cationic epoxy resin (III) and nonionic pentaerythritol/toluene diisocyanate/2‐ethylhexanol (PETOL‐TDI‐2EH,V) were investigated and the compositions of their electrodeposited films were obtained by Fourier Transform Infrared (FTIR) quantitative analysis to study the effects of soft segments (oxypropylene groups) contained in resinsIIIon the coemulsion and electrophoretic behavior.The results indicate that the deposition yield and throwing power of an emulsion of individualIIIare deeply affected by its average molecular weight (AMW). ResinIIIwith higher AMW has higher deposition yield but lower throwing power. Moreover, the deposition yield ofV/IIIcoemulsion also increases with increasing the AMW ofIII. On the other hand, the throwing power ofV/IIIcoemulsion is not related to the AMW ofIIIbut affected by the amount of soft segments inIII. Increasing “Soft segment” Content inIIIincreases the throwing power of coemulsion. Furthermore, at the conditions providing stable coemulsion, the composition of electrodeposited film is almost equal to the resin composition of

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090108

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractPoly(epichlorohydrin) was modified by nucleophilic substitution with some aliphatic potassium carboxylates containing terminal double bonds (10‐undecenoate, 4‐pentenoate and 3‐butenoate). In order to monitor the degree of substitution achieved, different reaction conditions were tested. The polyethers obtained were characterized by spectroscopic techniques, elemental analysis, thermal methods, viscosity determinations and osmometric measurements. A slight crosslinking and the reported main chain cleavage were both detected. Finally, it must be pointed out that, during the substitution reaction with the vinylacetate, isomerization to crotonic ester took

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090109

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractGel permeation chromatography calibration of ultra‐styragel columns for additive polyimide‐siloxane copolymers was developed using peak assignments. The results show that polystyrene (PS) calibration can be used with good approximation for the samples of molar masses higher than 1000 g mo

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052090110

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY