目的 通过乙酸、 高氯酸、 乙酸酐等对纳米纤维素（NCC）进行乙酰化改性， 再通过溶液浇铸法制备聚乳酸/改性纳米纤维素复合材料（PLA/mNCC）。方法 采用紫外可见分光光度计对PLA/mNCC进行透明性测试及透光率分析； 采用FE-SEM电镜观察mNCC在复合材料中的形貌； 采用动态热机械分析仪进行动态热力学分析。结果 与mNCC相比， NCC在PLA基体中的分散性更好。当mNCC质量分数小于4%时， 可较均匀地分散在聚乳酸基体中， 但随着mNCC含量的增加， 团聚现象明显； PLA/mNCC的储能模量随着 mNCC 含量的增加而提高， 但是 mNCC 的加入对材料玻璃化转变温度的影响非常小。结论 为改善PLA的加工性能提供一定的实验及理论依据。

In this paper, cellulose nanocrystal (NCC) was acetylated modified by acetic acid, perchloric acid and acetic anhydride. Then polylactic acid/modified NCC (mNCC) composite materials were prepared by solution casting. The transparency and light transmittance of composite materials were studied through UV visible spectrophotometer. The morphology of mNCC in composite materials was observed by FE-SEM electron microscopy. Dynamic thermodynamic analysis was carried out by Dynamic Mechanical Analyzer. The results showed that compared to NCC, mNCC had better dispersion in PLA matrices when the content of mNcc was less than 4%. The nano-particles tended to aggregate with further increase of mNcc content. The storage modulus of composite materials was improved with the increasing mNCC content and the existence of mNCC nearly had no influence on glass transition temperature. This study provides certain experimental and theoretical reference for the improvement of the processing performance of PLA.