微晶石墨在聚四氟乙烯中的高分散性实验研究

Experimental Study of High Dispersion of Microcrystalline Graphite(MCG)in Polytetrafluoroethylene(PTFE)

为解决聚四氟乙烯导热系数低、力学性能不佳等性能缺陷,研究共凝聚工艺,开发微晶石墨填充改性聚四氟乙烯新技术。考察聚四氟乙烯原料性质、微晶石墨的表面改性方法、分散剂、共凝聚温度、搅拌速率等因素对微晶石墨分散性的影响。结果发现,聚四氟乙烯分散液、共凝聚温度是影响复合材料的关键因素,选择聚四氟乙烯分散母液替代分散乳液为原料,采用硅烷偶联剂对微晶石墨进行表面改性处理后,以N,N-二甲基甲酰胺为分散溶剂,控制共凝聚温度为(19±3)℃,搅拌转速控制在300~400 r/min范围时,可以实现微晶石墨在聚四氟乙烯基体中的均匀分散。

In order to solve the performance defects such as low thermal conductivity and poor mechanical properties of PTFE,the co-condensation process was studied,and a new technology of MCG filling modified PTFE was developed.The ef⁃fects of the raw material property,the surface modification method,dispersant,co-condensation temperature,and stirring rate on the dispersion of MCG are investigated.The results show that the PTFE dispersion and co-condensation temperature are the key factors affecting the composite materials.When the dispersion solution is selected to replace the dispersed emulsion as raw material,with N and N-dimethylformamide as the dispersed solvent,the co-condensation temperature is 19±3℃,and the stirring speed is controlled in the range of 300~400 r/min,the uniform dispersion of microcrystalline graphite in the PTFE matrix can be realized.