Study on Synthesis and Thermal Properties of Polylactic Acid

Poly(1actic acid)(PLA), a kind of aliphatic polyesters, bears wonderful biologic compatibility and biodegradable properties. PLA that can finally biodegrade into CO2 and H2O under the influence of microorganism, water,acid or alkali, is harmless and non-toxic to the environment. L-lactide was prepared from lactic acid with stannous caprylate (Sn(Oct)2)as the catalyst. The high purity L-lactide can be get after 2 to 3 times recrystallization, then Polylactide acid was obtained by ring-opening polymerization with stannous caprylate (Sn(Oct)2) as the catalyst.Analysis of the structure of polylactide by IR, test thermodynamic properties of polylactide by DSC and Tg. The glass transition temperature of polylactide is 63.49 °C, the thermal decomposition temperature of polylactide is 267.29 °C.