中国塑料 ›› 2018, Vol. 32 ›› Issue (06): 72-78.DOI: 10.19491/j.issn.1001-9278.2018.06.011

• 材料与性能 • 上一篇    下一篇

原位反应法制备聚乳酸/聚氨酯共混物及性能

王玉龙,闫鹤轩,贺玉龙,刘凉冰,李振中   

  1. 太原工业学院
  • 收稿日期:2017-11-28 修回日期:2018-01-21 出版日期:2018-06-26 发布日期:2018-07-31
  • 基金资助:
    太原工业学院重点科学基金

Preparation and Properties of Poly(lactic acid)/Polyurethane Blends via In-situ Reaction

  • Received:2017-11-28 Revised:2018-01-21 Online:2018-06-26 Published:2018-07-31

摘要: 以聚乳酸(PLA)、聚四氢呋喃醚二醇(PTMG)和液化4,4′-二苯基甲烷二异氰酸酯(L-MDI)为原料,通过原位反应法制备了PLA/聚氨酯(PU)共混物,研究了PLA/PU共混物的反应原理、力学性能、断面形貌、动态流变性能以及结晶性能。结果表明,在原位反应中有微交联结构PU生成,且伴随着PLA的扩链和枝化反应;PLA/PU共混物的韧性得到显著提高,当PU含量为30 %(质量分数,下同)时,共混物的断裂伸长率、断裂韧性和缺口冲击强度分别达到230 %、134.13 MJ/m3和34.19 kJ/m2,较纯PLA分别增加了16.6、8.1和11.1倍,此时拉伸强度仍保持在较高水平(49.7 MPa);纯PLA和PLA/PU共混物熔体均为假塑性流体,共混物具有更高的储能模量和复数黏度;PLA/PU共混物比纯PLA的结晶速率高,晶体完善程度高。

Abstract: A series of poly(lactic acid) (PLA)/polyurethane (PU) blends were prepared by in-situ reaction of PLA with poly(tetramethylene ether glycol) (PTMG) and carbodiimide-modified MDI (L-MDI). The reaction principle, mechanical properties, fracture morphology, dynamic rheological properties and crystalline properties of the resulting blends were investigated. The results indicated that micro-crosslinked polyurethane was formed during the in-situ reaction process along with the chain extension and branching of PLA. The mechanical results demonstrated that the toughness of PLA/PU blends was significantly enhanced, and their elongation at break, tensile toughness and notch impact strength were improved by 230 %, 134.13 MJ/m3 and 34.19 kJ/m2, respectively, compared to pure PLA, when 30 wt% of PU was incorporated. The toughening mechanism may be due to the crazes and shear zones induced by PU rubbery phase in the matrix. The rheological results indicated that the melts of pure PLA and its blends with PLA were pseudoplastic fluid, and however, the blends had a higher storage modulus and complex viscosity. The crystallization test suggested that the PLA/PU blends had a higher crystallization rate and more perfect level of crystallization in comparison with pure PLA.