Abstract
Samples of polylactide (PLA) were synthesized by initiating lactide ring opening with glycidol using Sn(Oct)2 catalyst. Under low-temperature solution polymerization conditions, epoxide ring opening is precluded, leading to predominately linear epoxide capped PLA. With high-temperature bulk polymerization, simultaneous lactide and epoxide ring opening leads to hyperbranched polyesters characterized by linear PLA segments separating glycerol branch points. Molecular weights and extent of branching were determined by gel permeation chromatography (GPC), and the presence of branching was confirmed by solution viscosity measurements and g‘ calculations. Solution polymerizations yielded linear samples with controlled number-average molecular weights in the range 4800−19 200 g/mol. Number-average molecular weights of branched samples from bulk polymerization ranged from 19 800 to 100 800 g/mol. The branched samples exhibited relatively low polydispersity indices (PDI) in the range 1.48−2.00. Glass transition te...
Published Version
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