植物纤维增强PLA-EAA复合材料的制备与性能

开发新型环保材料以替代塑料已成为解决当前环境问题的主要途径，聚乳酸(PLA)虽然拥有良好的强度，而其较差的韧性极大地限制了其应用.针对此缺陷，本文以乙烯-丙烯酸共聚物(EAA)为增韧组分，蒸汽闪爆处理后的稻草纤维(SF)为增强组分加入PLA中，通过熔融挤出制备得到了不同原料配比的PLA/EAA/SF复合物，并通过对复合材料形态、热性能及力学性能的表征分析了EAA和植物纤维的加入及用量对复合材料性能的影响.研究结果表明：EAA用量的增加有效提高了复合物的韧性，但其强度低且抑制了聚乳酸的结晶进而使得复合物强度大幅降低；植物纤维的加入既体现明显的增强效果，又起到了连接两相作用，有利于EAA在PLA中的均匀分散，尤其是在高EAA含量的体系中，植物纤维加入还具有增韧效果；同时，EAA的加入还有利于改善复合材料的熔体流动性.当PLA/EAA/SF质量比为60/40/10时，复合材料冲击强度和断裂伸长率较纯PLA提高约15%和65%，且具有良好的力学性能及加工性.
Developing new environment-friendly materials to replace plastic has become a main way to solve the environmental problem.Though polylactic acid (PLA)owns high strength, poor ductility remarkably limits its application. Aiming at this drawback, ethylene-acrylic acid copolymer(EAA)and straw fibers (SF) treated by steam explosion were added into polylactic acid (PLA)as toughening components to prepare PLA/EAA/SF composites with various ratios of raw materials by melt blending. The morphology, thermal and mechanical properties of the composites were analyzed to figure out the effect of EAA and SF on the properties of composites. The results show that the increase of EAA can significantly improve the toughness of composites, while the strength of composites decreases greatly due to the intrinsic characteristic of EAA and the inhibition of crystallization. Moreover, the addition of SF makes a considerable enhancement effect to the composites. The dispersion of EAA in PLA is improved by the connection of SF and thereby resulting in a toughening effect at high content of EAA. Meanwhile, the addition of EAA is conducive to improve the melt fluidity of composites. When the content of PLA/EAA/SF is 60/40/10, the impact strength and elongation of composites increases 15% and 65% respectively than those of pure PLA, the composites exhibit good mechanical properties and processability.