The Chain Extension Modification of Recycled PLA Resin

The melt chain extension reaction of recycled polylactic acid(R-PLA) was investigated using epoxy compound as the chain extender in the torque rheometer.The effects of chain extender amount,reaction time and reaction temperature on the chain extension reaction were examined.The reactive conditions were optimized by orthogonal experiment using the impact strength and the melt flow rate as the main examination indicators.The results show that reaction temperature and the content of chain extender are the main factors affecting chain extension reaction.Under the optimum reaction conditions,the molecular weight of R-PLA increases from 5.8 × 104to 30.3 × 104,while the melt flow rate decreases from 8.28g /10min to 2.13g /10min correspondingly.The impact strength and the tensile strength of the chainextended R-PLA increase by 182% and 62% than those of neat R-PLA,respectively.The experimental facts indicate that the epoxy-based chain extender has the good effect on R-PLA chain-extending reaction.