聚四氟乙烯微粉预辐照接枝丙烯酸的研究

Grafting of Acrylic Acid Onto Polytetrafluoroethylene(PTFE) Micropowder via Pre-Irradiation

采用预辐照法对聚四氟乙烯(PTFE)微粉进行接枝丙烯酸改性,以改善微粉在水溶液中的分散性。研究了丙烯酸体积分数、适量浓H2SO4的添加、阻聚剂质量浓度、反应时间等因素对接枝率的影响。结果表明,接枝率随着丙烯酸体积分数(在50%以内)增加而单调递增;适量浓H2SO4能增强阻聚剂的阻聚效果,提高接枝率;在本实验条件下,阻聚剂最佳质量浓度为0.8 g/L;反应在3 h后接枝率即可达饱和。当丙烯酸在PTFE微粉上的接枝率达到10%以上时,改性PTFE微粉在氢氧化钠溶液中可达到均匀分散。

Grafting of acrylic acid （AAc） onto the surface of PTFE micropowders was per-formed by pre-irradiation method, in order to improve their dispersion in aqueous solution. The effects of various experimental parameters on the degree of grafting （G） were separately investigated, including： volume fraction of AAc, proper addition of concentrated sulfuric acid, mass fraction of inhibitor and reaction time. The result shows that G is increasing with increment of AAc concentration below 50%, and can be enhanced by adding a proper amount of sulfuric acid. Under our experimental conditions, G reached its saturated value when the mass concentration of the inhibitor was 0.8 g/L and the reaction time was 3 h. The introduction of more than 10G of poly（acrylic acid） chain on PTFE micropowders results in the good dispersion of PTFE micropowders in aqueous NaOH solution.