PLLA/PBAT单轴拉共混膜的力学性能及气体透过性

目的研究单轴拉伸聚乳酸/聚对苯二甲酸丁二酯(PLLA/PBAT)共混薄膜的热学、力学和气体透过性能。方法通过双螺杆熔融挤出后再进行单轴拉伸,制备出不同共混比例的无定型PLLA/PBAT共混薄膜材料,并对其热学、力学和气体透过性进行研究。结果 PLLA和PBAT是个完全不相容的共混体系,PBAT的添加加速了PLLA的冷结晶速度,改善了单轴拉伸PLLA薄膜的纵向和横向的柔韧性,最大断裂伸长率可达29%。提高了气体透过性和CO_2/O_2选择透过性,CO_2/O_2透过比相对于纯PLLA的3.8提高到7.6。结论柔性PBAT的添加改善了PLLA的刚性,提高了材料的柔韧性,PBAT对CO_2有较好的吸附性和扩散性,提高了材料的CO_2透过量和CO_2/O_2选择透过性能。

Mechanical Property and Gas Permeability of Uniaxial Drawn PLLA/PBAT Blending Film

The work aims to study the thermal, mechanical properties and gas permeability of uniaxial drawn poly(l-lactic acid)/poly(butylene adipate-co-terephthalate) (PLLA/PBAT) blending film. The uniaxial drawn PLLA/ PBAT blending films with different PBAT contents were prepared via a twin screw extruder, and the thermal, mechanical properties and gas permeability thereof were studied. PLLA and PBAT were totally incompatible blending systems. The addition of PBAT accelerated the cold crystallization rate of PLLA and improved the flexibility of uniaxial drawn PLLA film in the vertical and horizontal directions, with the maximum elongation at break of 29%. The gas permeability and permselectivity of CO2/O2 were improved. Compared to the transmittance (3.8) of pure PLLA, the transmittance of CO2/O2 was improved to 7.6. The addition of PBAT improves the rigidity of neat PLLA and enhances the flexibility of materials. Due to good adsorbability and diffusivity of PBAT for CO2, the CO2 permeability and the permselectivity of CO2/O2 of the material are well improved.