复合增塑剂聚乙二醇200与甘油对淀粉/PHA复合膜性能的影响

本文以羟丙基交联木薯淀粉、聚羟基脂肪酸酯(PHA)为成膜基材,甘油(GLY)为主增塑剂,聚乙二醇200(PEG200)为辅增塑剂,有机改性蒙脱土(OMMT)为增强剂,采用挤压吹塑法制备淀粉/PHA复合膜。研究了PEG200与GLY质量比对淀粉/PHA复合膜性能的影响。采用X-射线衍射(XRD)、扫描电镜(SEM)和红外光谱(FT-IR)分别对膜的结构、微观形貌和分子间相互作用进行了表征,并测试了膜的水蒸气阻隔性、机械性能、透光率和色度。结果表明,主增塑剂甘油对淀粉/PHA共混体系具有较好的增塑效果,且随着辅增塑剂PEG200的加入,促进了淀粉、PHA分子与OMMT间纳米插层结构的形成,所成复合膜表面较为平整光滑,且透光率、白度值增加;当PEG200与GLY质量比为8/92时,所成复合膜阻水性较好,具有较高的断裂伸长率;当PEG200与GLY质量比为12/88时,所成复合膜具有较高的抗拉强度和透光率;辅增塑剂PEG200的添加能够增强各分子间的相互作用。在制备淀粉/PHA复合膜中,PEG200是一种较好的增塑剂和增容剂,PEG200与GLY的质量比不宜超过12/88。

Effects of Composite Plasticizer Polyethylene Glycol 200 and Glycerol on the Properties of Starch/PHA Composite Films

Starch/polyhydroxyalkanoate (PHA) composite films were prepared using the blown film extrusion method with hydroxypropylated crosslinked tapioca starch and PHA as the film-forming substrate, glycerol (GLY) as the primary plasticizer, polyethylene glycol 200 (PEG200) as the secondary plasticizer, and organically modified montmorillonite (OMMT) as the enhancer. The effect of weight ratios of PEG200/GLY on the properties of the composite films was evaluated. The structure, microstructure, and molecular interactions of the films were analyzed by X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy, respectively. The water vapor barrier properties, mechanical properties, light transmittance, and color of the films were also measured. The results showed that the primary plasticizer GLY had a good plasticizing effect on the starch/PHA blend systems. Moreover, the addition of PEG200 facilitated the formation of intercalated nanostructures between starch, PHA, and OMMT, and increased the light transmittance and whiteness values of the composite films. Additionally, the surface of the composite films became flat and smooth. When the weight ratio of PEG200/GLY was 8/92, the composite films showed good moisture barrier properties and high elongation at break. When the weight ratio of PEG200/GLY was 12/88, the composite films showed a high tensile strength and good light transmittance. The addition of the secondary plasticizer PEG200 enhanced intermolecular interactions. During the preparation of starch/PHA composite films, PEG200 was a preferable compatibilizer and plasticizer, and the weight ratio of PEG200/GLY should be less than 12/88.