摘要:

AbstractNovel ABA block copolymers of poly(1,4‐phenylene sulfide) (PPS(A)) and poly‐(2‐methyl‐1,4‐phenylene sulfide) (PMPS(B)) were synthesised from bis(4‐bromophenyl) sulfone (BBS) by sequential reaction with copper(I) 4‐bromo‐2‐methylbenzenethiolate (CBMT) and copper(I) 4‐bromobenzenethiolate (CBT). PPS, PMPS and PPS/PMPS random copolymers were also prepared to aid block copolymer characterisation. Polymer fractions were studied by hot‐stage microscopy to evaluate melting ranges, and molar masses were computed from bromine end‐group concentrations and from gel permeation chromatography studies. Compositional analyses were made by IR and1H NMR spectroscopy leading to confirmation of the block copolymer structure and to evaluation of the degrees of polymerisation o

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880701

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractDifferential scanning calorimetry was used to evaluate first and second order transition temperatures and % crystallinity of poly(1,4‐phenylene sulfide) (PPS), poly(2‐methyl‐1,4‐phenylene sulfide) (PMPS), their blends and random and block copolymers comprising thio‐1,4‐phenylene and thio‐2‐methyl‐1,4‐phenylene units. Results are discussed in terms of the miscibility of PPS and PMPS in the melt phase and disruption of the crystallisation of PPS units by PMPS units. Microphase separation in the block copolymers was shown to be dominated by crystallisation of the PPS blocks. The application of Krause's microphase separation theory to prediction of the transitional behaviour of the block copolymers is c

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880702

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractSolution polymerisation of copper(I) 4‐bromobenzenethiolate (CBT) was effected at atmospheric pressure using a range of quinoline/pyridine solvent mixtures. Yields of poly(1,4‐phenylene sulfide) (PPS) were evaluated and PPS fractionated into toluene soluble (TS) and 1‐chloronaphthalene soluble (CNS) material. The fractions were characterised by end‐group analysis, viscometry and differential scanning calorimetry. The yield of CNS PPS is optimum for solvent mixtures comprising 70–80 vol.‐% quinoline, whereas the molar mass of this fraction is at a maximum for 95 vol.‐% quinoline. Results are discussed in terms of the effects of reaction temperature, complexing of CBT by quinoline and pyridine, and copper(I) bromide‐catalysed debromination. A low molar mass TS PPS fraction prepared in pyridine was subjected to detailed structural analysis by IR,1H NMR and Raman spectroscopy. Evidence is presented to show that this material contains disulfide linkages and that thiol end‐groupings are absent. These results are discussed relative to possible structures for poly(arylene sulfides). The relevance of this observation to high molar mass samples of PPS and their chain extension and degradative behaviour

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880703

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe block polymerization of 4‐methyl‐2‐oxetanone (β‐butyrolactone) with 2‐oxetanone (β‐propiolactone) proceeds fast with a yield of more than 90%, in the presence of potassium solutions in THF containing 18‐crown‐6. Poly(4‐methyl‐2‐oxetanone‐block‐2‐oxetanone) polymers having the expected molecular weight and composition are formed by this way. Their glass transition and melting temperatures as well as their melting enthalpies, determined by DSC, show a strict correlation w

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880704

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractDifferently substituted thiiranes were polymerized using an atropoisomeric chiral initiator: ZnEt2/(S)‐2,2′‐dihydroxy‐1,1′‐binaphthyl (DHBN) (mole ratio 1/1). It was observed that high stereoelectivities are obtained with monomers bearing small alkyl substituents and that the resolution efficiency of the initiator decreases as the bulkiness of the substituent increases. From the comparison of the results obtained with another initiator system, ZnEt2/(R)‐3,3‐dimethyl‐1,2‐butanediol (DMBD) (mole ratio 1/1), the use of ZnEt2/(S)‐DHBN could be shown to be more suitable for the polymerization of thiiranes with linear alkyl substituents. Contrary to the case of polymerization initiated by the system ZnEt2/(R)‐DMBD, the polymerization reaction of thiiranes with ZnEt2/(S)‐DHBN was usually accompanied by the production of the corresponding o

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880705

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe synthesis and characterization of liquid crystalline side chain polymers with mesogenic groups laterally attached to the polymer main chain are described. By variation of the terminal group, mesogenic moiety or spacer length, a change in the glass transition temperature, the nematic to isotropic transformation temperature and the stability of the nematic phase can be achieved. With increasing length of terminal groups, a distinct odd‐even effect of the nematic to isotropic phase transformation temperature and also a strong decrease of the glass transition temperature is observed. Macroscopic homeotropic alignment can be achieved in an electric or magnetic field. Conoscopic investigations show optical biaxial behavior of the nematic phase. A chiral nematic copolymer is the first example of a thermotropic biaxial cholesteric phas

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880706

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractBlock copolymers containing a rigid [oxy(2,6‐dimethyl‐1,4‐phenylene)] block and thermotropic poly[oxyterephthaloyloxy‐1,4‐phenylene‐hexamethylene (or/and decamethylene)‐1,4‐phenylene]blocks were synthesized. Their structures were examined by means of1H and13C NMR and X‐ray diffraction, and their liquid crystalline properties investigated by pola

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880707

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe addition reaction of methacrylic acid (6) to the telomer3, resulting from 2,3‐epoxypropyl methacrylate (1) and dodecanethiol (2), (DPn= 6) was studied. The percentage of addition at 60°C was found to be 32 after 24 h. When using an epoxide/methacrylic acid mole ratio of 2:1 Products were obtained which can easily be crosslinked by UV irradiation and which stick to aluminium to give water‐resistant prod

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880708

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe relative affinity of various mono and difunctional sulfoxides for lithium picrate in toluene was investigated by a competition method utilizing immobilized linear polyethers (glymes). In general, the difunctional sulfoxides were found to bind more strongly than the monofunctional sulfoxides. However, difunctional ligands which would result in eight‐membered ring chelated structures bound lithium ion more strongly than those which would result in six‐membered ring chelated structu

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880709

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractPolyacetylene‐block‐polystyrene was synthesized via an anionic‐to‐metathesis catalysis. The polymers obtained were characterized by UV/visible spectroscopy, IR spectroscopy and gel permeation chromat

ISSN:0025-116X    

DOI:10.1002/macp.1987.021880710

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY