摘要:

AbstractA new alternating block copolymer was synthesized from dihydroxy‐terminated poly‐(ether ketone sulfone) and bis(dimethylamino)‐terminated polydimethylsiloxane oligomers. The chemistry and the thermal properties are discussed. Surface chemical composition of films was analyzed by ESCA. Quantitative calculations showed a noticeable siloxane enrichment at the su

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180401

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractNew semi‐rigid poly(ester‐imide)s with cyanoazobenzene side chains were prepared by melt polycondensation of a diethyl isophthalate derivative of cyanoazobenzene withN,N′‐dihexanols of five aromatic diimides in the presence of zinc acetate. Differential scanning calorimetry (DSC) measurements and polarizing microscope observations demonstrated that the polymers have glass transitions (Tg) between 46 and 93°C and show no liquid crystalline (LC) properties. All poly(ester‐imide)s generated optical phase‐conjugate (PC) signals at high reflectivity by degenerate four‐wave mixing (DFWM) at low p

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180402

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractSupramolecular liquid‐crystalline main‐chain polymers have been obtained by self‐assembly of non‐mesomorphic bifunctional ligands and a transition metal ion. Stibazole dimers, bis[2‐(2‐{4‐[2‐(4‐pyridyl)vinyl]phenoxy}ethoxy)ethyl]ether(1)and 1,2‐bis[2‐(2‐{4‐[2‐(4‐pyridyl)vinyl]phenoxy}ethoxy)ethoxy]benzene(2)have been synthesized and complexed with silver trifluoromethanesulfonate (CF3SO3Ag). The metallomesogenic polymeric complexes formed by coordination bonds between the pyridyl groups of the stilbazole dimers and the silv

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180403

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractLow‐molar‐mass surfactants (S) and polyelectrolytes (PE) containing diazosulfonate chromophores which are photo‐labile and electrically charged were used for the formation of polyelectrolyte/surfactant complexes (PESC) in combination with commonly used polyelectrolytes and surfactants. The stable complexes are no longer water‐soluble and were characterized by means of nuclear magnetic resonance spectroscopy and in some cases by means of gel‐permeation chromatography measurements. Complexes with a 1 : 1 stoichiomctry with respect to charge are formed. Ultraviolet irradiation of the photo‐labile PESC resulted in the loss of the ionic i

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180404

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractPoly(acrylic acid)s of various molecular weights and different degree of hydrophobic modification have been synthesized by a polymer analogous reaction with tetradecylamine or copolymerization with styrene. Testing these amphiphilic polymers as stabilizers for the emulsion polymerization of styrene reveals that well stabilized latices are obtained within a certain range of molecular weight and hydrophobicity. As an example, the addition of 1 wt.‐% polymer with respect to the monomer allows the synthesis of polystyrene latices with a radius of about 100 nm in the absence of ionic initiators or polar comonomer

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180405

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractA novel fluorine‐containing polymer, poly[N‐(2,3,4,5,6‐pentafluorophenyl)maleimide], was prepared by the anionic polymerization ofN‐(2,3,4,5,6‐pentafluorophenyl)maleimide (PFPMI). Anionic polymerization with alkali metaltert‐butoxides gave poly(PFPMI) in 14–32% yield. Phenyllithium andsec‐butyllithium also afforded poly(PFPMI). No polymer was obtained with a radical initiator such as 2,2′‐azoisobutyronitrile. The polymerization took place only via the vinylene group of PFPMI and no appreciable side‐reaction occurred. The obtained poly(PFPMI) shows unimodal molecular weight distribution and begins

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180406

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe melting of poly(ethylene terephthalate) is analyzed by quasi‐isothermal, temperature‐modulated differential scanning calorimetry. The measurement is done by sinusoidally changing the temperature in the melting range (± 1.0 K). In the melting range a small portion of the sample melts reversibly. This observation is taken as a direct observation of the reversibility of melting of specific macromolecules as long as they are melting only partially and need no molecular nucleation for recrystalliza

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180407

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractEthylene was polymerized at 5 bar in a stirred powder bed reactor with silica supportedrac‐Me2Si[Ind]2ZrCl2/methylaluminoxane (MAO) at temperatures between 40°C and 80°C using NaCl as support bed and triethylaluminium (TEA) as a scavenger for impurities. For this fixed recipe and a given charge of catalyst. the average catalyst activity is reproducible within 10% for low temperatures. The polymerization rate and the rate of deactivation increase with increasing temperature. The deactivation could be modeled using a first order dependence with respect to the polymerization r

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180408

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractA general kinetic treatment of the system with intermolecular chain transfer followed by fast reinitiation is given. It leads to the broadening of the molecular weight distribution (MWD), the number of growing chains being invariable. Thus, this system can be considered as a special case of living polymerization. A general method has been elaborated allowing the determination of the ratio of the rate constant of propagation (kp) to the rate constant of the bimolecular transfer (k(2)tr) from the dependence of the MWD on monomer conversion. Numerical values ofkp/k(2)trequal to ≈ 102and 25 were thus determined for the polymerization ofL,L‐lactide (L,L‐dilactide) initiated with aluminium tris(isopropoxide) trimer ({Al(OiPr)3}3) and tributyltin ethoxide (nBu3SnOEt), respect

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180409

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe free‐radical terpolymerization of maleic anhydride (MSA), isobutyl vinyl ether (VIBE) and anethol (ANE) at 60°C is described. These three monomers do not homopolymerize under the conditions used. Binary copolymers are only obtained from MSA and one of the two investigated donor monomers, whereas the binary copolymerization of VIBE with ANE is not possible. In all terpolymers from these three non‐homopolymerizable monomers the MSA content amounts to about 50 mol‐%; VIBE is about twice as reactive as ANE. The terpolymerization can formally also be described under the assumption that two binary complexes (MSA/ANE (I) and MSA/VIBE (II)) are copolymerized. For this case the reactivity ratiosrI= 0,9 andrII= 1,7 are ob

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180410

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY