DHDOPO接枝改性多壁碳纳米管及其对聚乳酸性能的影响

Multi-Walled Carbon Nanotubes Grafting Modified with DHDOPO and Its Effect on the Properties of Polylactic Acid

首先将多壁碳纳米管(p-MWCNTs)用混合浓酸氧化成羧基化MWCNTs(MWCNTs-COOH),然后与氯化亚砜(SOCl_2)反应得酰氯化MWCNTs(MWCNTs-COCl);将9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)与二乙醇胺(DEA)反应制备DOPO的衍生物DHDOPO;再将DHDOPO与MWCNTs-COCl进行接枝反应得表面功能化的MWCNTs(MWCNTs-COO-DH);最后经熔融共混法制备聚乳酸(PLA)/MWCNTs-COO-DH复合材料。用核磁共振氢谱和透射电子显微镜表征MWCNTs-COO-DH的结构和微观形貌;用电子万能试验机、扫描电子显微镜、微型燃烧量热计等测定PLA/MWCNTs-COO-DH复合材料的力学性能、冲击断面形貌、燃烧性能及残炭层形貌。结果表明,实验成功合成了目标产物DHDOPO,并将其接枝到MWCNTs表面形成了典型核-壳结构的MWCNTs-COO-DH;适量的MWCNTs-COO-DH可均匀分散在PLA基体中形成良好的界面结合;质量分数为0.1%的MWCNTs-COO-DH可显著提高PLA的力学性能,并能降低其可燃性和火灾危险性。

Multi-walled carbon nanotubes（p-MWCNTs） firstly were oxided by mixed acids to obtain carboxylic MWCNTs（MWCNTs-COOH）. Then MWCNTs-COOH reacted with thionyl chloride（SOCl2） to obtain acyl chloride MWCNTs（MWCNTs-COCl）. The derivative of DOPO（DHDOPO） was obtained by the reaction of DOPO and diethanolamine（DEA）. Surface functionalized MWCNTs（MWCNTs-COO-DH） were obtained by the reaction of DHDOPO and MWCNTs-COCl. Polylactic acid（PLA）/MWCNTs-COO-DH composites were prepared via melt blending method. The structures and microscopic morphology of MWCNTs-COO-DH were investigated by 1H-NMR and transmission electron microscopy（TEM）. The mechanical properties, impact fracture morphology and combustion performance of PLA/MWCNTs-COO-DH composites were investigated by electronic universal testing machine, scanning electron microscope（SEM） and miniature combustion calorimeter（MCC）. The results show that DHDOPO is successfully synthesized and it is grafted on the surface of MWCNTs to form typical core-shell structures of MWCNTs-COO-DH. The proper amount of MWCNTs-COO-DH can be evenly dispersed in the PLA matrix to form a good interface. MWCNTs-COO-DH with a mass fraction of 0.1% can significantly improve the mechanical properties of PLA and reduce its combustion performance and fire risk.