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Synthesis of polysiloxanes with electron‐donating groups by anionic ring‐opening polymerization
Author(s) -
Chojnowski Julian,
Rózga Krystyna,
Fortuniak Witold,
Kowalewska Anna
Publication year - 1993
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19930730118
Subject(s) - siloxane , copolymer , polymerization , polymer chemistry , nucleophile , monomer , chemistry , ring opening polymerization , intramolecular force , ring (chemistry) , organic chemistry , polymer , catalysis
Anionic kinetically controlled ring opening polymerization of cyclotrisiloxane is explored as a method of synthesis of copolymers having the chain composed of dimethylsiloxane units and siloxane units bearing an uncharged nucleophilic (electron‐donating, ED) group. Model monomers for these studies are derived from hexamethylcyclotrisiloxane (D 3 ) in which one methyl group is replaced by the organophosphorus group of general formula ‐ (CH 2 ) n P(X)Ph 2 where X is lone pair, O or S. This method is shown to give significant advantages over the thermodynamically controlled homopolymerization and copolymerization of nucleophile‐substituted cyclosiloxanes which have so far been used for synthesis of ED substituted siloxane copolymers. The yield of the copolymers is much higher and the molecular weight distribution is narrow. The arrangement of the ED substituents along the chain, although not purely uniform, is much more regular as compared with the statistical distribution. The content of cyclic oligomers was higher than in the polymerization of unsubstituted D 3 , which is rationalized on the basis of intramolecular interaction of the counter‐ion with the ED groups.