reactive extrusion prepare high molecular weight polylactic acid

A batch-type stirred reactor and a twin-screw extruder combined continuous melt polymerization experiments, obtained from a lactic acid obtained by the continuous Ethyl lactate of the molecular weight of polylactic acid 150000. Twin-screw extruder of the low molar mass of lactic acid prepolymer further condensation in an extruder to prepare a high molar mass of the polylactic acid. The reaction temperature is 150 ℃, the amount of catalyst was 0.5%, a screw speed of 75 r / min when the double-screw magnessium lactate reaction rapidly and effectively increase the molar mass of the polylactic acid, and the reaction product was dispersed reduced coefficient of extrusion, uniformity better. The DSC curve by comparison, obtained by reactive extrusion of the polylactic acid polycondensation process crystallinity decreased, polylactic acid material which is to improve the performance in the course of a greater brittleness is beneficial.