羟丙甲纤维素增韧聚乳酸复合材料的制备及性能研究

选用羟丙甲纤维素（HMC）对聚乳酸（PLA）进行增韧改性，采用共混法制备了PLA/HMC复合材料，并对其流变性能、力学性能和结晶性能进行了系统分析。结果表明，PLA/HMC复合材料的表观黏度随剪切速率、温度和HMC含量的增加呈现逐渐下降的趋势；HMC在PLA基体中能够均匀分散，且PLA与HMC之间具有较好的相容性；PLA/HMC复合材料的断裂伸长率和冲击强度均在HMC含量为10 %（质量分数，下同）时达到最大值，HMC对PLA起到了增韧的效果；而PLA/HMC复合材料的拉伸强度则随着HMC含量的增加而逐渐下降；HMC降低了PLA/HMC复合材料的结晶性能，复合材料的熔点和结晶度均随着HMC含量的增加而逐渐下降。

Preparation and Properties of Hypromellose?toughened Poly（lactic acid） Composites

Hypromellose （HMC） was used as an impact modifier to prepare Poly（lactic acid）（PLA）/HMC composites by melt blending. The rheological， mechanical and crystallization properties of the composites were analyzed systematically. The results indicated that the composites exhibited a decrease in apparent viscosity with increasing shear rate， temperature and HMC content. HMC were uniformly dispersed in the PLA matrix due to good compatibility between PLA and HMC. The composites achieved the maximum elongation at break and impact strength at an HMC content of 10 wt%， indicating a good toughening effect on PLA. However， their tensile strength decreased gradually with an increase in the content of HMC. HMC could reduce the crystalline properties of the composites， resulting in a gradually decrease in their melting points and crystallinity with an increase in the content of HMC.