摘要:

AbstractThe present study reports values of reactivity ratios for ethylene/1‐hexene, ethylene/1‐octene and ethylene/1‐decene copolymerizations promoted by C2H4[Ind]2ZrCl2/MAO. The comonomer reactivities are markedly influenced by the number of carbon atoms of the α‐olefin. The ethylene/1‐decene copolymerization depends on the concentration of α‐olefi

ISSN:1022-1336    

DOI:10.1002/marc.1996.030170901

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractA rare case of thermodynamic miscibility has been demonstrated in the amorphous state (quenched glass as well as molten state) of a ternary blend system formed by poly(ether imide) and semicrystalline poly(ethylene terephthalate) and poly‐(butylene terephthalate). A single glass transition temperature (Tg) in the ternary blends was observed using differential scanning calorimetry and dynamic mechanical analysi

ISSN:1022-1336    

DOI:10.1002/marc.1996.030170902

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe synthesis and characterization of two unsymmetrically substituted star‐shaped oxadiazoles and of a dendrimer of the first generation are described. The key step in the synthesis is the intramolecular ring transformation of aromatic tetrazoles. The well‐defined compounds form stable amorphous glasses with high glass transition temperatures up to 222°C. They are promising candidates for organic light emitting di

ISSN:1022-1336    

DOI:10.1002/marc.1996.030170903

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractAn X‐ray imaging plate system has been applied for the first time to evaluate the crystallite modulusEcof orthorhombic polyethylene along the chain axis. TheEcevaluated by using the 002 reflection was 234.9 ± 12.6 GPa and that for the 004 reflection was 236.7 ± 3.4 GPa. The dispersion of the data was smaller for the 004 reflection than that for the 002 reflection. The so evaluated modulus has been found to be in good agreement with that reported by previous research

ISSN:1022-1336    

DOI:10.1002/marc.1996.030170904

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractIn the polymerization of ethene cocatalyzed with modified methylaluminoxane, the catalyst activities of the siloxane‐bridged dinuclear zirconocenes, tetramethyldisiloxanediylbis(cyclopentadienylindenylzirconium dichloride) (3) and hexamethyltrisiloxanediylbis(cyclopentadienylindenylzirconium dichloride) (4) were lower than that obtained with the siloxane‐bridged mononuclear zirconocene, tetramethyldisiloxanediyldicyclopentadienyldimethylzirconium (1). On the other hand, weight‐average molecular weight M̄wand ratio of weight‐ to number‐average molecular weights M̄w/M̄nof polyethene (PE) obtained with3or4were higher than those of PE obtained with1.For a binary mixture of1/3or1/4, it was found that the obtained PE exhibits a bimodal molecular weight distribution for an appropriate composition of the mixed zirconocenes. M̄w/M̄nof PE could be adjusted by changing the relative concentrations of the tw

ISSN:1022-1336    

DOI:10.1002/marc.1996.030170905

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractPoly(propylene) samples produced by heterogeneous Ziegler‐Natta catalysts containing different internal electron donors were fractionated by using temperature rising elution fractionation; some key fractions were analyzed with13C NMR. It was found that internal electron donors with different structures can convert aspecific active sites into different isospectrific ones. The employment of bis(2‐ethylhexyl) phthalate as internal electron donor leads to chemically inverted structures in the atactic fraction. This suggests that an internal electron donor may also exist in the environment of aspecific active si

ISSN:1022-1336    

DOI:10.1002/marc.1996.030170906

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractA novel biodegradable polyester having pendant amine functional groups was snythesized fromN‐(benzyloxycarbonyl)‐L‐aspartic anhydride (2) and 1,4‐cyclohexanedimethanol (3) by polycondensation reaction using p‐toluenesulfonic acid as a catalyst. The synthesized polymer4shows the characteristic ester carbonyl absorption peak at 1732 cm−1in the IR spectrum, and the NMR spectra were consistent with the IR data. Also, the elemental analysis showed that the experimental and calculated values were very close to each other. The weight‐average molecular weight of the polymers ranged from 1140 to 5050 and increased with increasing reaction time. This new polymer would have the potential of a drug deliver

ISSN:1022-1336    

DOI:10.1002/marc.1996.030170907

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractStyrene/N‐cyclohexylmaleimide copolymers with small polydispersities and controlled molecular weights were synthesized by a free radical copolymerization using an iniferter system consisting of benzoyl peroxide and 2,2,6,6‐tetramethylpiperidine‐N‐oxyl. Due to the interactions of the electropositive (styrene) and electronegative (N‐cyclohexylmaleimide) monomers the brutto polymerization rates are higher than for other living polymerizations initiated with the same iniferter system. The prepared copolymers were used as macroiniferters for bulk polymerization o

ISSN:1022-1336    

DOI:10.1002/marc.1996.030170908

出版商:Hüthig&Wepf Verlag    

年代:1996

数据来源: WILEY