GTA改性的PLA/PHB复合包装膜性能研究

目的研究三乙酸甘油脂(GTA)对PLA/PHB包装膜性能的影响。通过添加GTA提高PLA与PHB的相容性,改善包装膜的力学和透湿透氧性能。方法以GTA为增塑剂,聚乳酸(PLA)和聚β-羟基丁酸酯(PHB)为原料,利用熔融共混吹膜的方法制备PLA/PHB复合膜,通过对复合材料的DSC测试,以及透湿透氧性能、力学性能和红外光谱分析,研究GTA质量分数不同时对复合材料的拉伸性能、断裂伸长率、透湿透氧性能和相容性的影响。结果随着GTA含量的增加,薄膜拉伸强度整体呈下降趋势,同时断裂伸长率不断增大。当GTA质量分数大于4%时,拉伸强度急剧下降,断裂伸长率由原先的快速增长变为缓慢增长。透湿性能随GTA质量分数的增加先不断增大后减小,透氧性能增长不明显。通过DSC图结合包装膜断面结构微观图发现,GTA的加入减弱了聚合物分子链段之间的作用力,促进了链段的运动,使得薄膜断面上的微孔消失,形成层状结构。结论 GTA的加入改善了PLA和PHB的相容性,并且在GTA质量分数为4%时,复合包装膜既具有较好的拉伸性能和断裂伸长率,还具有较好的透湿透氧性能。

Properties of GTA Modified PLA/PHB Composite Packaging Film

The work aims to study the effect of glyceride triacetate (GTA) on the properties of PLA/PHB packaging film. By adding GTA, the compatibility of PLA with PHB, and the water vapor permeability and oxygen permeability of the packaging film were improved. PLA/PHB composite film were prepared by melt blending for film blowing with GTA as plasticizer, and polylactic acid (PLA) and poly (3-hydroxybutyrate) (PHB) as raw materials. The effects of different GTA mass fractions on the tensile property, elongation at break, water vapor permeability and oxygen permeability and compatibility of the composites through the DSC test of the composites and analysis on the water vapor permeability and oxygen permeability, mechanical property and infrared spectroscopy were studied. With the GTA content increased, the tensile strength of the film decreased integrally, but the elongation at break showed a tendency to increase. When the mass fraction of GTA was more than 4%, the tensile strength decreased sharply, and the elongation at break increased rapidly first and then slowly. The water vapor permeability increased firstly and then decreased with the increase of GTA mass fraction, and the oxygen permeability showed no significant increase. By observing the DSC diagram and the microgram of the packaging film section, it was found that the addition of GTA weakened the force acted between the polymer molecular chain segments and promoted the movement of chain segments, making the pores of the film cross section disappeared to form a layered structure. The addition of GTA improves the compatibility of PLA and PHB. When the mass fraction of GTA was 4%, the composite packaging film has better tensile property and elongation at break with better water vapor permeability and oxygen permeability.