Synthesis of polylactide under inert atmosphere and vacuum

Abstract

The ring-opening polymerization (ROP) of L- lactide was carried out in bulk using various initiators along with triphenylphosphine (PPh 3) as co-initiator. Equimolar addition of triphenylphosphine increased the molecular masses of polylactide (PLA). The polymerization was carried out at 403.15 K up to 155 hr. Different experiments were carried out over a wide range of monomer to initiator (M o/I o) ratios. It was found that maximum molecular weight of polylactide was observed when M o/I o ratio was 2500-2700. Polymerization reactions were carried out under two different environments in the reaction vessel, an inert cover and a partial vacuum. The average molecular weight of polylactide was determined by using size exclusion chromatography. The increase of polymerization time increased the weight average molecular weight but after prolonged reaction time, the molecular weight decreased gradually. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.