ISSN:
0025-116X
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The homopolymerization of 2,2-dimethyltrimethylene carbonate (1), 2-allyloxymethyl-2-ethyl-trimethylene carbonate (2) and ε-caprolactone (3) with sec-butyllithium (sec-BuLi), tri-sec-butoxyaluminium (Al(O-secBu)3), diethylzinc (ZnEt2) and dibutyldimethoxytin ((Bu)2Sn(OMe)2) in toluene at 80°C results in a reaction product consisting of a high-mole-cular-weight polymer and a homologous series of oligomers. The weight ratio polymer/oligomers, under standardized conditions, depends on the type of initiator. The sequence of monomeric units in the copolymers is statistical, for all initiators used. For sec-BuLi and Bu2Sn(OMe)2 the distribution arises both from random addition of the monomers to the active chain end and from transesterification, while with Al(O-secBu)3 and ZnEt2 the addition of the monomers is non-selective.For poly[(2,2-dimethyltrimethylene carbonate)-stat-(2-allyloxymethyl-2-ethyltrimethylene carbonate)] the carbonyl region of the 13C NMR spectrum is suitable for diad analysis, for poly[(2,2-dimethyltrimethylene carbonate)-stat-(ε-caprolactone)] the methyleneoxy region is most indicative. The assigment of the diads was made on the basis of model compounds.
Zusätzliches Material:
5 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/macp.1992.021930517
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