PLLA/TPU共混挤出物流变性及聚集态结构的研究

Study on Rheological Properties and Aggregated Structure of PLLA/TPU Blends

通过熔融共混制备了聚L-乳酸(PLLA)和热塑性聚氨酯(TPU)的共混物,并研究了该PLLA/TPU共混挤出物的流变性能及聚集态结构。结果表明:该PLLA/TPU共混物为假塑性流体,随着共混体系中TPU含量的增加,共混物熔体的表观黏度提高,且非牛顿指数减小,即共混物的黏度对剪切速率的敏感性增强;另外,随着剪切速率或TPU含量的增加,PLLA/TPU共混挤出试样的结晶度呈下降趋势,其断裂强度与模量亦有所降低,而断裂伸长率则有所提高。

The blends of poly（L-lactic acid） （PLLA） and thermoplastic polyurethane （TPU） were prepared by means of melt blending. The rheological properties of the PLLA/TPU blends and aggregation structure of the extrudates were investigated. The results show that the PLLA/TPU blends are pseudoplastic fluid. With the increasing TPU content in the blends, the apparent viscosity of the blend melts increases and non-Newton index decreases, which reveals that the apparent viscosity of the melts is more shear rate sensitive when the TPU content increasing. In addition, with an increment of the shear rate or the content of TPU, the crystallinity of the PLLA/TPU blends reduces, the breaking strength and the module decrease, while the breaking elongation increases.