接枝改性纤维素纳米晶(CNC)增强水性聚氨酯(WPU)制备CNC/WPU复合涂膜

Reinforcing Waterborne Polyurethanes with Grafting Modified Cellulose Nanocrystals for CNC/WPU Composite Coating

采用TEMPO氧化体系和聚乙二醇(PEG)对纤维素纳米晶(CNC)进行了表面接枝改性,并与水性聚氨酯(WPU)共混制备了改性CNC/WPU纳米复合涂膜。通过扫描电子显微镜(SEM)观察、拉伸与硬度测定及热重分析(TG)研究了纳米复合涂膜的结构与性能。结果表明,质量分数为3%的改性CNC能够均匀分散在WPU基质中,无明显的团聚现象。纳米复合涂膜的硬度较纯WPU大幅度提升,拉伸强度提高了126%,30%的失重温度升高了17℃,热稳定性得到明显改善。实验结果表明改性CNC对WPU具有显著的增强效果。

Cellulose nanocrystals(CNC)were modified by TEMPO-mediated oxidation system and polyethylene glycol(PEG)so that Modified CNC was obtained.Modified CNC were blended with Waterborne Polyurethanes(WPU)and modified CNC/WPU complex coating by the solution-casting process was thus performed.Structure and properties of the nanocomposite films were studied by scanning electron microscopy(SEM),tensile test,hardness test and thermogravimetric analysis(TG).Results indicate that the modified CNC with a mass fraction of 3%can be uniformly dispersed in the polyurethane matrix without obvious aggregation.Compared with the pure WPU,the hardness of nanocomposite coating is significantly enhanced,the tensile strength of nanocomposite coating is increased by 126%,and the 30%loss temperature of nanocomposite coating is increased by 17℃,the thermal stability is obviously improved.Experimental results show that the modified CNC have a obvious reinforcing effect on WPU.