辐照支化聚乳酸的结晶及流变性能

摘要

采用三羟甲基丙烷三丙烯酸酯(TMPTA)、光引发剂、聚乳酸(PLA)作原料,经紫外光辐照,制备了支化聚乳酸.进一步研究了TMPTA添加量对PLA力学性能、结晶性能及流变特性的影响.结果表明,支化结构使分子链的物理缠结点增多,支化PLA表现出更高的冷结晶温度(Tcc),其中TMPTA添加量为2.5％的PLA的Tcc比线型PLA提高了9.2℃,也使PLA弹性模量、复数黏度得到提高.另外,支链也使聚合物分子链间距增大,PLA的韧性得到提高,TMPTA添加量为2.5％的PLA的冲击强度达到5.8kJ/m2,比线型PLA提高了70.6％.%Branched polylactic acid (PLA) was synthesized by UV irradiation with trimethylolpropanetriacrylate (TMPTA),photoinitiator and PLA as raw materials.The effects of TMPTA addition on the mechanical properties,crystallinity and rheological properties of PLA were studied.Results show that,the branching structure increases the number of physical entanglement among the molecular chains.And the branched PLA shows higher cold crystallization temperature (Tcc),and the Tcc value of PLA with 2.5wt％ TMPTA is 9.2 ℃ higher than linear PLA.The elastic modulus and complex viscosity of branched PLA are also improved.Meanwhile,branch chains increase the molecule distance,resulting in the improvement of PLA toughness.The impact strength of PLA with 2.5wt％ TMPTA reaches 5.8 kJ/m2,70.6％ higher than that of linear PLA.