聚乳酸聚氨酯嵌段预聚体增韧聚乳酸/热塑性聚氨酯共混物的研究

本研究合成了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了PLA/TPU/PLA-b-PUP超韧共混物。通过拉伸试验、冲击试验、SEM、FT-IR、DSC和TGA研究了共混物的力学性能、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上的活性基团发生了反应,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,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倍和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。

Study on polylactic acid polyurethane block prepolymer toughened polylactic acid/thermoplastic polyurethane blends

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, FT-IR, 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 times 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.