Property of polylactic acid synthesized from 85% lactic acid via direct condensation polymerization

Abstract

This research work is a study of the synthesis of polylactic acid (PLA) from 85% lactic acid via condensation
polymerization. Stannous chloride and stannous chloride mixed with p-toluene sulphonic acid were used as
catalyst for condensation polymerization reaction. The reaction was conducted at three different levels of
temperature namely 140, 150 and 160oC with reaction time of 24, 36 and 48 hr. The polymer obtained was
characterized by FT-IR, 13C-NMR and 1H-NMR. Thermal property and weight average molecular weight of PLA
were determined by DSC and GPC, respectively. It was found that the optimal condition to synthesize PLA with
the highest weight average molecular weight (Mw=32,956) was occurred at temperature of 160oC, reaction time
of 36 hr and using stannous chloride as catalyst.