摘要:

AbstractThree linear phenyl ketones, 4‐methyl‐1,7‐diphenyl‐3‐heptanone (6a), 2,8‐diphenyl‐4‐nonanone (6b), and 5‐methyl‐2,8‐diphenyl‐4‐nonanone (6c), and four cyclic ketones, 1‐phenethyl‐2‐(3‐phenylpropionyl)cyclopentane (4a), 1‐(3‐phenylbutyryl)‐2‐(2‐phenylpropyl)cyclopentane (4b) and their cyclohexane homologues (5aand5b), were synthesized as models of styrene copolymers bearing carbonyl groups in the chain, and their photochemical degradation was studied in various solvants at wavelengths>280 nm. This study has shown that both Norrish mechanisms, i.e., the type I scission in α‐position of the carbonyl and the type II photoelimination, which occur with the models, take place in a similar fashion with the copolymers. The relative part and the efficiency of each photodegradation depend on the solvent, the linear or cyclic character of the chain, as well as on the substitution. Photodegradation studies of the models have also allowed us to explain the photochemical behaviour of the particular copolymers and especially the faster fragmentation of linear chains, and to elucidate the mechanisms

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821001

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe telomerization of isobutene was investigated using redox catalysis, free radical, and particularly cationic initiation. The influence of the initiator on the degree of polymerization and the structure of the telomers was studied. Redox and free radical telomerization with CCl4and CCl3Br were found to permit synthesis and identification of the monoadduct structure. Cationic telomerization gives regular structure compounds and the molecular weights are higher than those obtained by other methods of telomerization.

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821002

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractRandom copolymerization of aspartic acid with lactic acid and with glycolic acid was carried out usingo‐phosphoric acid as catalys

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821003

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractAzoxy and azo type polyesters were obtained by combination of an azoxybenzene or an azobenzene group as a mesogenic core with different flexible chain lengths of ethylene glycol groups. The thermal properties of these mesomorphic polymers are discussed related to their chemical structures. The mesomorphic temperature region becomes narrower with increasing flexible chain length. Further, the transition temperature from the mesomorphic phase to the isotropic liquid is higher for the azoxy type polyester than for the azo type polyester.

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821004

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractPolyurethanes were synthesized by reaction of a rigid molecule, 3,3′‐dimethyl‐4,4′‐biphenyldiyl diisocyanate (DBD), with flexible molecules, oligoethylene glycols (di‐, tri‐, and tetraethylene glycol) or α,ω‐alkanediols, and some of their thermal properties were studied. Poly(DBD‐oligoethylene glycol)s are amorphous polymers which exhibit no mesomorphic phase. Poly(DBD‐alkanediol)s are found to show a mesomorphic phase depending on the number of methylene units in the alkanediol. The polymers having methylene units from five to twelve are crystalline and show a mesomorphic phase. On the contrary, polymers having less than four methylene units do not show a mesomorphic phase since thermal decomposition of the polymers occurs before melting. The transition temperature from the mesomorphic phase to the isotropic liquid decreases with increasing length of the flexible chain of alkanediol. Ternary polymers are obtained by reaction of DBD with a mixture of hexanediol (HD) and dodecanediol (DD). The ternary polymers containing a small amount of HD and DD give a cl

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821005

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractPoly(imide‐urethane)s having a methylene group between the imido and the oxycarbamoyl groups were synthesized by addition polymerization of bis(N‐hydroxymethyl)imides and diisocyanates in hexamethylphosphoric triamide. Properties of the resulting poly(imide‐urethane)s were studied in comparison with those of the corresponding poly(imide‐urethane)s having no methylene group. The resulting carbamic ester linkage was found to be much more stable against nucleophiles compared with the carbamic ester linkage without the methylene group. However, there appeared to be not much difference in thermal stability between these two kinds of l

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821006

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractSeveral telomers of vinyl alcohol with chloroform and diethyl phosphonate were prepared. TheirDPnwere measured by several analytical methods (elemental analysis, NMR spectroscopy, viscosimetry). Their small molecular size, their good water‐solubility, and their very low acute toxicity allow to use them as drug‐carriers in pharmacological applicati

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821007

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractFree radical copolymerization of a macromer and a vinylic or acrylic monomer is a novel method of synthesis of graft copolymers. Each macromer unit gives yield to a graft. Accurate characterization of the samples obtained, especially by means of proton NMR, is possible. The distribution of the grafts along the chain is random. The overall molecular weights of the copolymers formed are low, however.

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821008

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe synthesis of poly(acylhydrazone)s from aldarodihydrazides, principallyD‐glucarodihydrazide, was studied. Polymers were produced on reaction of the dihydrazides with dialdehydes and with aliphatic ketoaldehydes and diketones, but not with aromatic ketoaldehydes or aromatic diketones. The polymers, which have only limited solubilities that are not appreciably improved by copolymerization, undergo a tautomeric change on treatment with acid or alkali to give yellow‐coloured polymers. Of the poly(acylhydrazone)s prepared, that fromD‐glucarodihydrazide and 2,3‐butanedione had the best overall properties, giving strong, flexible, colourless films on casting from DMSO s

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821009

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractStyrene polymerized by AIBN as initiator results in telechelic α,ω‐bis(1‐cyano‐1‐methylethyl)oligostyrenes (1). The functionality,fCN, was found to be 1,99 ± 0,05 in the molecular weight range up to 2000 and theMw/Mn‐values were found to be<1,5 after complete consumption of the initiator. Using methyl 2,2′‐azoisobutyrate as initiator, oligostyrenes with two ester endgroups were obtained. The conversion of styrene was limited by “dead end” conditions as described by Tobolsky. The efficiency was 0,9 under the preparative conditions used. The cyano endgroups were converted into amino endgroups by hydrogenation and into carboxyl endgroups by hydrolysis. Telechelic α,ω‐bis(2‐isocyanato‐1,1‐dimethylethyl)‐ and α,ω‐bis(1‐isocyanato‐1‐methylethyl)oligostyrenes4and6were obtained from the amino product2by the phosgene method and from the carboxyl product3by the Weinstock/Curtius reaction, respectively. Connecting these telechelic styrene blocks by a polyreaction results in polymers in

ISSN:0025-116X    

DOI:10.1002/macp.1981.021821010

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY