Direct melt polymerization and characterization of polylactic acid modified by ethylene glycol

Direct melt polymerization is applied to modify polylactic acid with ethylene glycol with a view to improving its degradability and hydrophillicity.The influences of type and quantity of catalyst,time and temperature of melt polymerization reaction,and feed ratio on the synthesis of the polymer were discussed.The resultant product was characterized with intrinsic viscosity,FT-IR and DSC.The results were as follow: when the mole ratio of LA/EG of 100∶3,and Sn(Otc)2 as catalyst with usage amount of 0.5 wt%,reacting at 170 ℃ and 0.095 MPa for 8 h,the maximum Mη of the product reached 16 374,with degradability and hydrophillicity improved.Increasing the dosage of EG decreased the intrinsic viscosity and glass-transition temperature(Tg) of the product gradually.