纤维素纳米晶对聚乳酸结晶行为的影响

摘要

聚乳酸(PLA)因具有良好的生物相容性和生物降解性而受到广泛的关注,但其结晶速率慢和结晶度低,大大地限制了PLA的使用.基于此,本文从结晶改性入手,通过改进后的两步法将纤维素纳米晶(CNC)均匀分散到PLA中.利用透射电镜(TEM)、傅里叶红外光谱(FTIR)、差示扫描量热仪(DSC)、偏光显微镜(POM)、力学性能测试、X射线衍射测试(XRD)等表征手段测试了CNC的加入对PLA复合材料结晶行为的影响.结果表明,加入质量分数3%的CNC,PLA的结晶度提高到47.5%,复合材料的拉伸强度也提高了10%,并且在145℃等温结晶的晶核数量明显增多,晶粒尺寸明显减小,球晶生长速率提高.%The slow crystallization rate and low crystallinity of polylactide ( PLA ) restrict its practical applica-tions. CNC was added to PLA to improve the crystallization behavior of PLA. The results showed that,with the ad-dition of 3wt% CNC,the crystallinity degree of nanocomposites increased to 47. 5% and the tensile strength of the PLA/CNC nanocomposite was enhanced by 10%. The spherulitic morphology study revealed that CNC acted as an efficient nucleating agent for the crystallization of PLA,as the spherulites size became significantly smaller with the addition of CNC and the crystallization rate was increased.