纤维素纳米纤维对聚乳酸结晶、流变和拉伸性能的影响

Study on crystallization,rheological behavior and tensile properties of poly(lactic acid)/cellulose nanofiber composites

采用熔融共混-注射成型制备了聚乳酸(PLA)/纤维素纳米纤维(CNFs)可生物降解纳米复合材料,利用差示扫描量热仪、流变测试、拉伸性能测试等手段,考察了CNFs含量对PLA/CNFs复合材料结晶行为、流变特性和力学性能的影响规律。结果表明,少量的CNFs能均匀分散在PLA基体中,CNFs可作为PLA的异相成核剂,提高结晶速率常数,缩短半结晶时间,CNFs的含量为5%(质量分数,下同)时,半结晶时间由纯PLA的10.4 min缩短至2.9 min;CNFs体现出润滑作用,使PLA/CNFs复合材料的储能模量和损耗模量均低于纯PLA;CNFs的含量为3%时,复合材料的断裂伸长率较纯PLA提高了41.2%。

Polylactic acid(PLA)/cellulose nanofiber(CNFs)nanocomposites were prepared through melt blending and injection molding,and the effect of CNFs on their crystallization behavior,rheological and mechanical properties were in⁃vestigated.The results indicated that CNFs could be uniformly dispersed in the PLA matrix at a small content.CNFs can be used as a heterogeneous nucleating agent to induce the crystallization of PLA,improving the crystallization rate constant and reducing the half crystallization time.Compared to neat PLA,the nanocomposites with 5 wt%CNFs pre⁃sented a decrease in the half crystallization time from 10.4 min to 2.9 min.The rheological experimental results demon⁃strated that the lubrication and dilution effects of CNFs reduced the storage modulus and loss modulus of PLA.Com⁃pared to neat PLA,the elongation at break of the nanocomposite containing 3 wt%CNFs was improved by 41.2%.