相反转工艺对环氧乳液稳定性的影响

Effect of phase inversion process on stability of epoxy emulsion

采用自制大分子乳化剂E-10000,以相反转乳化法制备了环氧乳液,通过测定电导率来确定相反转点。探讨了乳化剂用量、乳化温度、搅拌速率和乳化时间对乳液稳定性及固化膜性能的影响。结果表明,当乳化剂质量分数小于17%时,体系为不完全相反转,大于17%时才为完全相反转。所得最优制备工艺为:乳化剂质量是环氧树脂质量的20%,乳化温度78℃,搅拌速率1 200 r/min,乳化时间40 min。此时环氧乳液稳定性好,平均粒径374 nm,且粒径分布较窄。其固化膜的铅笔硬度为2H,柔韧性2 mm,附着力0级,冲击强度50 kg·cm,吸水率6.29%。

An epoxy emulsion was prepared via phase inversion emulsification with a home-made macromolecular emulsifier E-10000. The phase inversion point was determined by conductivity testing. The effects of emulsifier content, emulsification temperature, stirring rate and emulsification time on the stability of emulsion and properties of its cured film were studied. The results showed that the phase inversion will not be complete until the mass fraction of emulsifier is up to 17%. The optimal preparation conditions were obtained as follows： mass fraction of emulsifier 20% （with respect to the mass of epoxy resin）, emulsification temperature 78℃, stirring rate 1 200 r/min, and emulsification time 40 min. The emulsion prepared thereunder has a good stability, an average particle size of 374 nm and a narrow particle size distribution. Its cured film has a pencil hardness of 2H, flexibility 2 mm, adhesion strength 0 grade, impact strength 50 kg·cm and water absorption rate 6.29%.