木质素/聚乳酸/EVA热塑性复合材料的研究

Study of Thermoplastic Composites Consisting of Lignin/PLA/EVA

摘要: 随着人们环保意识的逐渐增强，作为造纸及生物乙醇工业副产物的木质素的资源化利用势在必行。本文以聚乳酸为基体，木质素为增强体，一定量的EVA作为增塑剂，通过熔融共混，注塑成型，制得了一系列木质素基热塑性复合材料。利用红外测试、扫描电镜测试、TG-DSC测试、力学测试、流变测试一系列方法对其结构及性能进行了表征。结果表明：复合材料组分之间没有明显的化学反应。木质素的加入在一定程度上降低了复合材料的热稳定性；随木质素含量的增加弯曲强度降低，由于木质素属于刚性材料，木质素含量多时弯曲模量有所增加；乙烯–醋酸乙烯共聚物(EVA)的加入可以提高木质素在复合材料中的分散性和相容性，使两相的粘合力增强。这项研究对高含量木质素复合材料的制备提供一定的理论及实验基础。

Abstract: With the gradual enhancement of people’s environmental awareness, the utilization of lignin as a by-product of the papermaking and bioethanol industry is imperative. In this paper, a series of lignin-based thermoplastic composite materials were prepared by using polylactic acid as the ma-trix, lignin as the reinforcement, and a certain amount of EVA as a plasticizer through melt blending and injection molding methods. A series of methods including infrared spectrum, scanning electron microscope, TG-DSC, mechanical test and rheological test were used to characterize their structures and performances. The results showed that, no obvious chemical reactions occurred among the components of the composites; addition of lignin reduced the thermal stability of the composite material to a certain extent; the bending strengthes of the composites decreased with the increase of the lignin content, due to the rigidity of lignin. While the composite’s lexural modulus increased with the lignin content; addition of EVA can improve the dispersion and compatibility of lignin in the composite material, and enhance the adhesion of the two phases. This study provides theoretical and experimental basis for the preparation of high content lignin composite.