DCP对生物基单体原位聚合增韧聚乳酸效果的影响

Influence of DCP on Toughening Efficacy of PLA Modified via In-situ Polymerization of Biobased Monomers

目的改善大豆油多元醇和L-赖氨酸乙酯二异氰酸酯作为生物基单体原位聚合增韧聚乳酸(PLA)共混物的界面相容性。方法在上述2种单体原位聚合增韧PLA的过程中,添加少量过氧化二异丙苯(DCP),诱导聚合形成的聚氨酯增韧相与PLA基体之间发生增容反应;然后再研究添加DCP后,对所制备PLA共混物微观结构、力学性能及结晶/熔融性能的影响规律。结果加入DCP后,发现聚氨酯增韧相凝胶含量增加,同时共混物界面相容性得到改善。当DCP质量分数为0.8%时,共混物缺口冲击强度达到最高(12.3 kJ/m^(2)),约为纯PLA的4.4倍。随着DCP质量分数从0增加1.2%,共混物中PLA组分的熔融温度和结晶度逐渐从163.8℃和7.3%降至155.6℃和3.2%。结论在生物基单体原位聚合增韧PLA体系中添加少量DCP,可制备出一种具有良好韧性的全生物基PLA材料。

The work aims to improve interphase compatibility of the PLA blend system toughened by vegetable oil polyol and L-lysine ethyl ester diisocyanate(LDI)as biobased monomers via in-situ polymerization.In the process of toughening PLA by the above 2 monomers via in-situ polymerization,a small amount of dicumyl peroxide(DCP)was incorporated to initiate reactive compatibilization between the in-situ formed crosslinked polyurethane toughening phase and PLA matrix.Then,the effects of DCP on microstructure,mechanical properties,and crystallization/melting properties of the prepared PLA blend system were investigated,respectively.The addition of DCP resulted in not only an increase in gel content of polyurethane as a toughening phase,but also an improvement in interfacial compatibility.When the weight content of DCP was 0.8%,the notched impact strength for PLA blend system reached the highest value(12.3 kJ/m^(2))that was 4.4 times that of neat PLA.Besides,with an increase in the amount of DCP from 0 to 1.2%,both melting peak temperature and crystallinity associated with PLA component in the blend system decreased gradually from 163.8℃and 7.3%to 155.6℃and 3.2%,respectively.Therefore,a kind of full biobased PLA material with good toughness can be obtained by incorporating a small amount of DCP into the PLA system toughened with biobased monomers via the in-situ polymerization approach.