增塑剂对聚乳酸/热塑淀粉复合膜性能的影响

目的改善聚乳酸(PLA)/热塑淀粉(TPS)共混复合膜的使用性能。方法探究乙酰柠檬酸三丁酯(ATBC)和环氧大豆油(ESO)2类增塑剂对复合膜力学性能、透湿性、透光性、微观结构及热力学性能的影响。结果增塑剂的添加可显著改变复合膜力学性能,当ATBC添加量(质量分数)从10%升至20%时,复合膜断裂伸长率增加38倍,而抗拉强度仅为前者的36%。单一ATBC或ESO的添加对复合膜透湿性及透光性影响基本一致,且优于复合增塑剂效果。增塑剂对复合膜体系能够起到一定增容效果,但会造成热分解起始温度下降。对于单一增塑剂,ATBC的增塑效果更为优良;ATBC和ESO复合增塑剂虽具有一定协同作用,但由于二者相容性较差,在总添加量相同的情况下,其对复合膜的增塑作用相较于单一ATBC未展现出明显优势。结论 ATBC添加量为20%的复合膜拥有最佳综合性能。

Effects of Plasticizer on Properties of PLA/TPS Composite Films

The paper aims to improve the performance of polylactic acid (PLA)/thermoplastic starch (TPS) blended composite film. The effects of acetyl tributyl citrate (ATBC) and epoxidized soybean oil (ESO) plasticizer on mechanical properties, moisture permeability, light transmittance, microscopic structures and thermodynamic properties of the composite. The addition of plasticizer could significantly change the mechanical properties of the composite film. When the dosage of ATBC increased from 10% to 20%, the elongation at break of the film increased by 38 times, while the tensile strength was only 36%. The addition of single ATBC or ESO had a substantially uniform effect on the moisture permeability and light transmission of the composite film, and the effect was superior to the blended plasticizer. The two plasticizers had certain synergistic effects, but using simultaneously could cause a decrease in the onset temperature of thermal decomposition. For the single plasticizer, ATBC was better than ESO. However, due to their poor compatibility, ATBC/ESO mixture did not exhibit obvious advantages over the single plasticizer ATBC under the same dosage. The composite film with an ATBC addition of 20% has the best overall performance.