纳米纤维素晶须增强增韧聚(L-乳酸)复合材料的制备与表征  

Preparation and characterization of nano cellulose whiskers reinforced and toughened poly(L-lactic acid)based composites

作　　者：刘桦[1] 罗丙红[1] 陈睿鹏 周世裕 黄耀基 周长忍[1] 

机构地区：[1]暨南大学材料科学与工程系,人工器官及材料教育部工程研究生中心,广州510632

出　　处：《复合材料学报》2015年第6期1703-1713,共11页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(81171459);广东省产学研结合项目(2013B090500107)

摘　　要：通过酸解法制备了具有纳米尺寸和一定长径比针棒状的纳米纤维素晶须(NCW),利用NCW表面的羟基引发L-丙交酯开环聚合,合成了表面接枝聚(L-乳酸)(PLLA)链段的接枝纤维素晶须(g-NCW);采用溶液浇铸法制备了PLLA膜以及不同配比的NCW/PLLA和g-NCW/PLLA复合膜。对接枝改性前后的NCW的形貌与性能进行了表征,研究了复合膜的形貌、结晶性能、热稳定性、亲/疏水性和拉伸性能。结果表明:NCW的形貌与结晶性能在接枝改性后变化不大,但在乙醇和PLLA溶液中的分散性得到明显改善;当NCW与L-丙交酯的物质的量之比为1∶5时,g-NCW表面PLLA链段的接枝率约为23.61%。NCW和g-NCW作为异相成核剂,显著提高了PLLA基体的结晶速率;并且,加入晶须改善了材料的亲水性和热稳定性。添加一定量的NCW和g-NCW到PLLA中,可有效增强增韧PLLA基体;随着晶须含量增加,复合膜的拉伸强度和断裂能先增大后下降;当NCW和g-NCW的质量分数为5%时,NCW/PLLA和g-NCW/PLLA复合膜的拉伸强度和断裂能分别达到22.02 MPa和20.01 MPa以及102.39J/m^3和117.83J/m^3,均达到最大值。由于g-NCW在基体中良好的分散性以及与基体间的界面结合,g-NCW/PLLA复合膜的拉伸强度和韧性明显优于相应的纯PLLA和NCW/PLLA膜。The needle rod-like cellulose whiskers（NCW）with nano size and certain length-diameter ratiowere prepared by acid hydrolysis,and then were surface modified with poly（L-lactic acid）（PLLA）segments through thering-opening polymerization of L-lactide initiated by surfacehydroxyl groups to obtain grafted cellulose whiskers（g-NCW）.PLLA membrane and NCW/PLLA and g-NCW/PLLA composite membranes with different ratios were prepared by solution casting method.Morphologies and properties of the modified and unmodified NCW were observed,and the morphologies,crystallization properties,thermostability,hydrophilicity/hydrophobicity and tensile properties of the composite membranes were studied too.The results show that the morphology and crystallization property of NCW change little after graft modification,but the dispersion of g-NCW in ethanol and PLLA solution is improved significantly.The grafting percentage of PLLA segments on surface of g-NCW is 23.61% as the ratio of amount of substance of NCW to L-lactide is 1∶5.The crystallization rateof PLLA matrix increases significantly due to the heterogeneous nucleating effect of the NCW and g-NCW.In addition,the hydrophilicity and thermostability of material are improved by the introduction of the whiskers.When adding some content of NCW and g-NCWto PLLA,the strength and toughness of the PLLA matrix are evidently improved.With the content of whiskers increasing,the tensile strength and breaking energy increase first and then decrease for NCW/PLLA and g-NCW/PLLA composite membranes,as the mass fraction of NCW and g-NCW is 5%,the highest tensile strength and breaking energy of 22.02 MPa and 20.01 MPa,102.39J/m^3 and 117.83J/m3 are obtained for NCW/PLLA and g-NCW/PLLAcomposite membranes respectively.Due to the excellent dispersionof g-NCW in matrix and interfacial adhesion,the tensile strength and toughness of g-NCW/PLLA composite membranes are obviously superior to those of the pure PLLA and NCW/PLLA membranes.

关 键 词：纳米纤维素晶须 聚(L-乳酸) 复合材料 增强增韧 亲水性 

分 类 号：O633.1[理学—高分子化学]