纤维素纳米晶/聚乳酸复合材料的制备与性能

Preparation and Properties of Cellulose Nanocrystal /Poly( Lactic Acid) Composites

用酸解法制备了纤维素纳米晶(CNC),然后用醋酸乙烯酯和丙烯酸丁酯通过自由基聚合的方法对CNC进行包覆改性,制得改性纤维素纳米晶(m-CNC),再将m-CNC和聚乳酸(PLA)通过溶液浇注法制备复合材料。利用透射电子显微镜、红外光谱、扫描电子显微镜、广角X射线衍射、力学和降解性能测试研究了m-CNC/PLA复合材料的结构与性能。结果表明,酸解法制备的棒状CNC直径约为5 nm^26 nm,长度约为40 nm^380 nm。随着m-CNC含量的增加,m-CNC/PLA复合材料的拉伸强度呈上升趋势,当m-CNC的含量为8%时,m-CNC/PLA复合材料的拉伸强度与纯PLA的相比增加了43.3%。在PLA中加入适量的CNC或m-CNC,PLA的结晶度提高而晶粒尺寸减小。m-CNC的加入减缓了m-CNC/PLA复合材料在模拟体液中的降解速率,但加速了其在土壤中的降解。

Cellulose nanocrystals( CNCs) were prepared by acid hydrolysis of cotton fibers,then modified using vinyl acetate and n-butylacrylate as monomer through radical polymerization. The modified CNC( m-CNC) and poly( lactic acid)( PLA) were compounded to prepare composites via solution casting technique. The structure and properties of m-CNC /PLA composites were analyzed by TEM,FT-IR,mechanical testing,SEM,WAXD and degradation test. The results show that rod-like CNCs obtained through acid hydrolysis have the diameter of 5 nm ~ 26 nm and the length of 40 nm ~ 380 nm. The tensile strength of m-CNC /PLA composites increases with increasing content of m-CNC. As the mCNC content increases from 0% to 8%,the tensile strength increases by 43. 3%. The PLA phase in m-CNC /PLA composites presents higher crystallinity but smaller crystallites compared with the pure PLA. Adding m-CNC into PLA slows down the degradation of m-CNC /PLA composite in simulated body fluid but accelerates its degradation in soil.