Cellulose nanocrystals (CNC) were carboxylated through an organic solvent free esterification method using l-malic acid (MA) to improve performance of transparent poly(methyl methacrylate) (PMMA) nanocomposites. A series of CNC carboxylated with a degree-of-substitution (DS) of 0, 0.035, and 0.20 were obtained. The presence of grafted carboxyl groups was characterized by Fourier transform infrared (FT-IR) spectroscopy and ¹³C NMR analysis, meanwhile effects of content and DS of CNC on the structure, thermal, mechanical, and optical transparency properties of the nanocomposites were assessed. The results indicated that the homogeneous dispersion of CNC and a favorable PMMA-CNC interface were necessary to enhance the properties of nanocomposites. Facilitated through hydrogen bonding interactions, the resulting films demonstrated that a low percentage loading of CNC with high DS worked as effective reinforcing agents, producing stronger and tougher films than neat PMMA films, with an improved thermal stability and retention of good transparency.

通过使用1-苹果酸（MA）的无溶剂无酯化方法，将纤维素纳米晶体（CNC）羧化，以提高透明聚（甲基丙烯酸甲酯）（PMMA）纳米复合材料的性能。得到一系列的CN，其取代度（DS）为0、0.035和0.20的羧化了。傅立叶变换红外光谱（FT-IR）和¹³表征了接枝羧基的存在进行13 C NMR分析，同时评估了CNC的含量和DS对纳米复合材料的结构，热，机械和光学透明性的影响。结果表明，CNC的均匀分散和良好的PMMA-CNC界面对于增强纳米复合材料的性能是必要的。通过氢键相互作用的促进，所得膜证明了具有高DS的低百分含量的CNC作为有效的增强剂，比纯PMMA膜产生更坚韧的膜，并改善了热稳定性并保持了良好的透明性。