中文摘要：

采用硫酸水解法制备了纤维素纳米晶，并用于增强热塑性聚氨酯弹性体。通过XRD、红外光谱、DMA和AFM等表征手段对纤维素纳米晶的表面基团以及溶液共混法制备的纤维素纳米晶／聚氨酯复合材料的微观结构和力学性能进行了研究。结果表明，质量分数2％的纤维素纳米晶能够在聚氨酯基体中均匀分散，复合材料的拉伸强度为纯聚氨酯薄膜的184％，且断裂伸长率没有损失。含有质量分数5％纤维素纳米晶的复合材料呈现特殊的相结构，此时复合材料的储能模量最大，玻璃化转变温度最高。

英文摘要：

The cellulose nanocrystals with high aspect ratio and uniform size were prepared by sulfuric acid hydrolysis method, and were used to enhance the thermoplastic polyurethane elastomer. The morphology, size distri- bution of cellulose nanocrystals, and mechanical properties and dynamic mechanical properties of composite films were studied by means of FTIR, XRD, AFM and DMA. The results showed that 2% cellulose nanocrystals could be uniformly dispersed in the polyurethane matrix, which tensile strength of the composite was 184% of the polyurethane matrix, and the elongation at break was not decreased. The composite containing 5% cellulose nanocrystals showed a special morphology, which the storage modulus and the glass transition temperature were the highest.