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The ring‐opening polymerization of D , L ‐lactide in the melt initiated with tetraphenyltin
Author(s) -
Kohn F. E.,
Van Den Berg J. W. A.,
Van De Ridder G.,
Feijen J.
Publication year - 1984
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1984.070291255
Subject(s) - polymerization , polymer chemistry , molar mass distribution , polymer , ring opening polymerization , lactide , chemistry , materials science , organic chemistry
Melt polymerization conditions for D , L ‐lactide initiated with tetraphenyltin were studied with regard to polymer molecular weight and weight distributions. “Single” polymerization, “multiple” polymerization (four or eight reactions at the same time), and time‐dependent studies are described. Single polymerizations using constant initiator concentrations resulted in a broad scattering of nonreproducible molecular weight values. Multiple polymerizations at constant initiator concentrations, however, resulted in nearly identical molecular weight profiles. Multiple polymerizations at different initiator concentrations did not show an inverse dependency of initiator concentration on polymer molecular weight. Both the single and multiple melt polymerizations resulted in rather broad molecular weight distributions. The presence of hydrolysis products of lactide during the melt polymerization most likely has a detrimental effect on molecular weight. After a short induction period the rather slow polymerization of D , L ‐lactide resulted in a maximal molecular weight followed by a slight decrease in molecular weight to a constant value. It is concluded that the polymerization of D , L ‐lactide in the melt initiated with tetraphenyltin does not proceed through a “living” mechanism.