以硫酸水解得到的纳米纤维素晶须(CNW)悬浮液为原料,以二氯甲烷和硝酸的混合物为硝化剂制备了能够稳定分散在丙酮中的表面硝酸酯化的改性CNW.采用元素分析、红外、X射线衍射等手段对改性物的结构进行了表征和分析.将改性CNW与硝化纤维素混合,通过溶液浇铸法制备了一系列硝化纤维素纳米复合材料膜片.考察了改性CNW的添加量对膜片拉伸性能的影响规律.结果表明:当改性CNW的添加量为2.0％、3.5％、5.0％和7.0％时,硝化纤维素纳米复合材料膜片的拉伸强度、杨氏模量和断裂伸长率都得到了不同程度的提高.其中,当改性CNW的添加量为3.5％时,膜片的综合力学性能最好,与空白膜相比,拉伸强度提高了21.7％,拉伸模量提高了32.7％,断裂伸长率提高了123.6％.%A simple chemical modification route was demonstrated using cellulose nanowhiskers (CNW) prepared by sulfuric acid hydrolysis as raw material and a mixture of nitric acid and dichloromethane as nitrification agent. The bulk degree of substitution ( DS) of modified CNW was quantified by elemental a-nalysis. The structure of modified CNW was analyzed by FT-IR and X-ray diffraction. The modified CNW can be well dispersed readily in solvents with low polarity,such as acetone,and retain their original integrity and size. Nitrocellulose nanocomposite films with different CNW contents were processed by solution casting. The tensile strength,modulus and strain at break of the nanocomposites filled with 2. 0% ,3.5% ,5.0% and 7. 0wt% modified CNWs are improved compared to the neat matrix. The tensile strength,modulus and elongation at break of the composite film filled with 3. 5wt% CNW are increased by 21. 7% ,32. 7% and 123. 6% ,respectively.
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