Direct condensation polymerization of lactic acid

Abstract

In order to synthesize the higher molecular weight poly(lactic acids) by direct condensation polymerization of lactic acid, dipentaerythritol was used-as a chain branching agent. Poly(lactic acids) of high molecular weight, 67000(Mn), was obtained by using antimony trioxide catalyst with good color. This poly(lactic acids) showed Tg of 54.8 degrees C, Tm of 147 degrees C and cold crystallization temperature of 115 degrees C. The polymer could be melt processed into transparent films. Tensile modulus of 311 Kg/ mm(2), tensile strain of 21% and tensile strength of 12.41 Kg/ mm2 were obtained for film collected at 400%/min and drawn 4 times.