聚乳酸/蒙脱土纳米复合材料的原位聚合及表征

摘要

High molecular weight polylactide/montmorillonite nanocomposites were obtained through in-situ melt polycondensation method in which the montmorillonite(MMT) was added after dehydration and before the polycondensation. The results of XRD and TEM show that exfoliated nanocomposites are obtained when the addition of montmorillonite is 0.5 ％ (mass fraction),and both intercalated and exfoliated structures are obtained when it is 1 ％. When the mass fractions of montmorillonite are 0. 5 ％ and 1％,the tensile strength, elongation at break and impact strength of the nanocomposites are better than those of pure polylactide (PLA). When they are higher, these mechanical properties become worse. SEM image of PLA-MMT0.5 (the mass fraction of montmorillonite is 0.5 ％) shows a fracture toughness characterization.%从乳酸出发,在乳酸脱水结束后、缩聚开始之前将蒙脱土和催化剂一起加入反应体系,通过原位熔融直接缩聚法制得较高分子量聚乳酸/蒙脱土纳米复合材料.XRD和TEM结果表明:蒙脱土(MMT)添加量为0.5%(质量分数,下同)时制得剥离型纳米复合材料,添加量为1%时产物剥离与插层结构并存.力学性能研究表明:MMT含量为0.5%和1%时,聚乳酸(PLA)的强度和韧性有明显提高,MMT含量进一步增加,力学性能下降.SEM对断裂面的观察显示出,MMT含量为0.5%时,PLA是韧性断裂特征.