表面活性剂影响磁粉共凝聚F46乳液的研究

使用十六烷基三甲基溴化铵(CTAB)、烷基酚聚氧乙烯醚(NP)和辛基酚类聚氧乙烯醚(S-13)3种不同表面活性剂乳化铁硅铬磁粉,通过共凝聚方法制备四氟乙烯与六氟丙烯共聚物(F46)包覆乳化后磁粉(F46/铁硅铬磁粉)的复合材料。通过扫描电子显微镜(SEM)表征共凝聚粒子的形貌,通过热重分析仪(TG)测试共凝聚粒子的热稳定性,通过矢量网络分析仪(VNA)测定样品的磁介性能。结果表明:在共凝聚过程中,阳离子型表面活性剂CTAB不仅对铁硅铬磁粉进行乳化,利于磁粉分散,而且在整个共凝聚体系起到破乳作用。采用CTAB乳化磁粉的共凝聚反应,出现凝胶的时间为第12 min,整个共凝聚过程耗时33 min,相比于其他共凝聚反应,缩短了反应时间;且加入质量分数10%乳化剂的磁粉剩余质量分数为0.59%,磁粉残余量最低。F46/铁硅铬磁粉复合材料的磁导率在18.00 GHz下还能保持在1.10左右,介电常数在1.00~18.00 GHz范围内稳定在2.30以下,F46/铁硅铬磁粉复合材料的磁介性能有所改善。

Study on Influence of Surfactant on Magnetic Powder for Hetero-coagulation -F46 Latex

Three different surfactants, cetyltrimethylammonium bromide(CTAB), alkylphenol ethoxylates(NP) and octyl phenol ethoxylates(S-13) were used to prepare the composite materials made of F46(tetrafluoroethylene-hexafluoropropylene copolymer) hetero-coagulated with emulsified magnetic powder. The morphologies of magnetic particles and co-condensate particles were characterized by scanning electron microscope(SEM) and the thermal stability of co-condensate particles were measured by thermal gravimetric analyzer(TG). Finally, the magnetic dielectric properties of the samples were measured by vector network analyzer(VNA). The results showed that CTAB cationic surfactant not only emulsified the magnetic powder, but also demulsified the whole hetero-coagulation system. The gelation time of the hetero-coagulation reaction of CTAB emulsified magnetic powder was 12 min, and the time of the whole hetero-coagulation process was 33 min. Compared with other hetero-coagulation reactions, the reaction time was shortened. And the residual amount of 10% emulsified magnetic powder was 0.56%. The magnetic particle residue is the lowest. The permeability of the composite material with F46/FeSiCr magnetic powder can remain at about 1.10 in 18.00 GHz, and the dielectric constant is stable below 2.30 in the range of 1.00~18.00 GHz. The magnetic properties of F46/FeSiCr magnetic powder composite material have been improved.