聚乳酸聚氨酯嵌段预聚体增韧PLA/TPU共混物

Study on polylactic acid polyurethane block prepolymer toughened PLA/TPU blends

合成聚乳酸聚氨酯嵌段共聚物预聚体(PLA-b-PUP),以其作为聚乳酸(PLA)和热塑性聚氨酯(TPU)的活性相容剂,通过原位反应增容制备PLA/TPU/PLA-b-PUP超韧共混物.通过拉伸试验、冲击试验、SEM、FTIR、DSC和TGA研究共混物的力学性能、热性能和增韧机理.结果表明,PLA-b-PUP中的异氰酸酯基团与PLA和TPU上的活性基团发生反应,显著改善了PLA/TPU共混物两相界面的相容性.随着PLA-b-PUP的加入量增加,共混物中PLA的玻璃化转变温度和相对结晶度逐渐降低,当PLA-b-PUP的质量分数为PLA/TPU共混物的4%时,共混材料的断裂伸长率和缺口冲击强度分别达到无相容剂时的8.12和2.73倍,表现出良好的增容增韧效果.添加PLA-b-PUP后,共混物的初始分解温度有所降低,但最快分解温度有所提高.

In this study,polylactic polyurethane block prepolymer(PLA-b-PUP)was synthesized and used as the active compatibilizer of polylactic acid(PLA)and thermoplastic polyurethane(TPU).PLA/TPU/PLA-b-PUP supertoughened-blends were prepared by in-situ reaction.The mechanical properties,thermal properties and toughening mechanism of the blends were investigated by tensile test,impact test,SEM,FTIR,DSC and TGA.The results showed that the isocyanate groups in the PLA-b-PUP reacted with the active groups on PLA and TPU,which significantly improved the compatibility of the two-phase interface of PLA/TPU blends.With the addition of PLA-b-PUP,the glass transition temperature and relative crystallinity of PLA in the blend gradually decreased.When the mass fraction of PLA-b-PUP was 4%of that of PLA/TPU blend,the elongation at break and notch impact strength of the blend were 8.12 and 2.73 times of those without compatilizer,respectively,showing a good capacity and toughening effect.After addition of PLA-b-PUP,the initial decomposition temperature decreased,but the fastest decomposition temperature increased.