PLA及其复合材料高效预结晶动态干燥工艺

研究了生物高分子PLA及其复合材料高效预结晶动态干燥的方法。在物料干燥过程中引入高速搅拌和真空工艺,使其在干燥过程中加快脱水,避免由于水分蒸发导致的物料黏结。考察了高效预结晶动态干燥和传统干燥两种方法对PLA及其复合材料的干燥温度、干燥时间、力学性能、加工性能、扭矩和热焓的影响。结果表明:高效预结晶温度以不超过95℃为宜,此方法可使生物高分子PLA及其复合材料最大扭矩降低20%～40%,热焓升高,性能有所改善,除湿干燥时间由原来的6～14h缩短为1～2h,而且不会出现黏粒和下料困难的现象。

High Efficiency Pre-crystallization Dynamic Drying Method for Biodegradable Poly-lactic Acid (PLA) and Its Composites

A kind of dynamic drying method for biopolymer compound biodegradable poly-lactic acid(PLA) and its composites,via pre-crystallization process,has been developed in this study.The high-speed stirring and vacuum technology were introduced into the process of drying material in order to quicken dehydration and avoid matter sticking.The effects of two kinds of drying method which were pre-crystallization and desiccant dehumidifi cation on drying time,drying temperature profile,mechanical properties,processability,melting torque,and enthalpy of PLA and its composites were investigated.The results showed that feasible pre-crystallization drying temperature for biopolymer compound was not more than 95℃,and the maximum torque of PLA and its composites decreased by 20%～40%.The enthalpy increased and the mechanical properties of PLA and its composites improved.Drying time was reduced to 1～2 h by using this new method in contrast to 6～14 h by using traditional method.Moreover,the phenomenon of compound stick together and hard discharge was not happened.