摘要:

AbstractThe electrochemical polymerization of some Schiff's base‐type monomers like pyrrole‐2‐aldehyde azine, N,N′‐di(2‐pyrrolylmethylene)‐1,4‐diaminobenzeneSystematic name: 2,2′‐[1,4‐phenylenebis(nitrilomethylidyne)]dipyrrole., and N,N′‐di(2‐pyrrolylmethylene)‐4,4′‐diaminobiphenylSystematic name: 2,2′‐[4,4′‐biphenylylenebis(nitrilomethylidyne)]dipyrrole.proceeds as a precipitating polymerization to the anodic compartment. The voltammetric study of monomers and polymers using Pt electrodes and paste‐carbon electrodes were carried out. The results are in agreement with the MO calculations using the Hückel approximation for

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390101

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractA new macromonomeric peroxyinitiator (MMPI) was synthesized by the reaction of polytetrahydrofurandiol (p‐THF‐diol), Mw(1000), isophorone diisocyanate, 2,5‐dimethylhexyl‐2,5‐dihydroperoxide and 2‐isocyanatoethyl methacrylate. Homopolymerization of MMPI at 80°C gave crosslinked polytetrahydrofuran (poly‐THF) with swelling ratios in CHCl3varying between 1.4 and 4.2.Styrene polymerization initiated by MMPI at 80°C in bulk gave crosslinked poly‐THF‐b‐polystyrene block copolymers. The overall rate constant, k, was found to be 1 · 10−4(L mol−1)1/2s−1by keeping the polymer yield below 15%. Swelling ratios of the crosslinked block copolymers in CHCl3were between 2.7 and 75 according to the concentration of MMPI and the polymerization time. In case the MMPI concentration was kept constant while the polymerization time was increased, swelling ratios were found between 3.55 and 7.07. Thermogravimetric analysis showed that the crosslinked block copolymers were still containing undecomposed peroxy groups, so they can thermally initiate styrene polymerization in order to obtain multicompo

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390102

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe preparation of a SiC coating on a carbon fiber surface using a sol‐gel mixture of tetraethyl orthosilicat (TEOS) and phenolic resin was studied. FTIR and SEM investigations indicated that the SiC coating can be formed by carbothermal reduction of the sol‐gel mixture at 1420°C for 15–20 min in an argon atmosphere. TGA of the coated fiber was also performed, showing that the SiC coating improves the thermooxidative stability of the carbon fiber. With the thickness of the obtained coating of 0.47 μm using a C/Si ratio of 4, this treatment does not affect the carbon fiber s

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390103

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe new dicationic nickel complex [dppfNi(MeCN)4][BF4]2(dppf = 1,1′‐bis(diphenylphosphino)ferrocene) in the presence of diethylaluminium chloride (AIEt2CI) exhibited high activity on the 1,3‐butadiene polymerization. Reaction time, temperature and aluminium/nickel molar ratio were optimized in order to achieve maximum activity and selectivity. Conversions higher than 90% were obtained in contrast to other nickel‐based systems using phosphine ligands, the resulting polybutadiene showed highcis‐1,4 (<80%) content and only small amount of 1,2‐units (2%). All polymers presented low molecular weights

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390104

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractEnd‐reactive methacrylate oligomers, obtained by free‐radical polymerization of methyl, n‐butyl and tert‐butyl methacrylate with tetraphenylsuccinonitrile as initiator were used as free‐radical macroinitiators for the polymerization of styrene to prepare block copolymers. It could be shown by gel‐permeation chromatography coupled with FTIR spectroscopy that the oligomers are incorporated as segments in the block copolymers.The tert‐butyl ester groups of tert‐butyl methacrylate‐styrene block copolymers were hydrolysed and neutralized to yield amphiphilic polymers which were characterized by thermogravimetry and dynamic mechanical thermal analysis. The existence of an extended rubbery plateau proved that triblock ionomers had been obtained, due to termination by combination of growing styre

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390105

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper deals with the influence of oligomers, namely propylene oil and butylene oil, of different molecular weight on the adhesive properties of atactic polypropylene (aPP) and its mixtures with styrene‐2‐ethylhexyl acrylate (S‐EHA) copolymer. The mechanical work of adhesion Amof the mixture containing atactic polypropylene and oligomer increases with the molecular weight of the oligomer, which was more significant in the case of propylene oil. For ternary mixtures aPP‐S‐EHA copolymer/oligomer a maximum of adhesion can be observed if the content of the S‐EHA copolymer in the mixture reaches about 30 mass‐%. In the absence of oligomers in the mixture a minimum of adhesion can be observed for this composition, which can be attributed to the incompatibility of the remaini

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390106

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractPoly(methyl methacrylate) is a preferred material used in X‐ray lithography. One effect observed after irradiation is a change of its chemical structure, combined with a decrease of the molar mass. This was analysed quantitatively using size exclusion chromatography combined with multi‐angle laser‐light scattering. Based on a kinetic model, an equation was derived which gives a satisfactory description of the dependence of the molar mass on the radiation

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390107

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe irradiation of poly(methyl methacrylate) changes the chemical constitution of the polymer. In addition to a decrease in molar mass further radiation‐induced radical reactions cause changes in the chemical constitution of the polymer. Analysis of the reaction products shows that formation of long‐chain branching can be excluded. Along with degradation of the chain lengths, ester groups in the side chains are attacked. The result is a modified polymer with a physical and chemical behaviour different from that of the starting poly

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390108

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe structural changes in poly(methyl methacrylate) (PMMA) caused by radiochemical reactions are predominantly governed by a decrease in molar mass and a splitting of side chains. It can be shown that the removal of the irradiated parts of PMMA is not a pure physical dissolving, but that there is a chemical reaction proceeding, the products of which are well soluble in polar solvents. This special type of reaction restricts this process on the irradiated areas and hence explains the high selectivity of the developing of the lithographic structures. Knowledge of these mechanisms leads to the prediction that isotactic PMMA shows an increased selectivity of the developing agent. Further improvements and optimizations of etching and developing are therefore possible.

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390109

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractFür die Copolymerisation von 1,3‐Butadien mit Propylenoxid wurde nach dem Vergleich der drei Katalysatorsysteme Nd(Oct)3/Al2Cl3ET3/Al(i‐But)3, Ni(Oct)2/ BF3OEt2/AlEt3und Al(i‐But)3/I2/TiCl4das Titankatalysatorsystem eingesetzt. Neben dem Einfluß der Monomerzusammensetzung auf den Umsatz, die Microstruktur, die Copolymerzusammensetzung, die Molmassen sowie die Molmassenverteilungen wurden auch die Polymerisationszeit und das Aluminium/Titan‐Verhältnis untersucht. Die Copolymerisationsparameter wurden nach Kelen‐Tüdős zu rButadien= 0,9 und rPropylenoxid= 3,9 bestimmt. Der Copolymernachweis erfolgte über13C‐NMR‐Spektroskopie und Extraktionsuntersuchungen in Verbindung mit1

ISSN:0003-3146    

DOI:10.1002/apmc.1996.052390110

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY