磷酸酯反应型乳化剂在叔丙乳液中的应用及防腐性能

Application of phosphate reactive emulsifier in vinyl versatate-acrylate emulsion and its anticorrosive property

采用新型环保型磷酸酯反应型乳化剂(LRP-10)替代常规的非反应型乳化剂,新癸酸乙烯酯(VV-10)为叔碳单体,采用半连续种子乳液预乳化法合成叔丙乳液。探究了乳化剂种类、用量以及VV-10用量对乳液及涂膜的凝胶率、吸水率、耐水性、Ca^(2+)稳定性和附着力等性能的影响,并通过FTIR、TEM、粒径、接触角和电化学测试对乳液及涂膜进行了结构与防腐性能表征,分析其防腐机理。结果表明,与常规乳化剂制得的纯丙乳液相比,当LRP-10用量为2%,分配比为种子乳液∶预乳化液为1.5∶0.5,VV-10用量为10%时,制得的叔丙乳液涂膜吸水率为由18.87%下降到2.18%,耐水测试168h后涂膜仅轻微发白,很快恢复,涂膜水接触角由50.5°提高至85.5°。涂层阻抗由1.40069×10^(6)Ω·cm^(2)提高至7.38137×10^(8)Ω·cm^(2),腐蚀电流密度最小为1.2268μA/cm2,腐蚀电位最正为-0.19753V。LRP-10的反应性及钝化作用与VV-10的疏水与屏障作用产生协同效应,形成“双层屏障”,使水性丙烯酸涂膜的防腐性能大幅提高。

A new type of environment-friendly phosphate reactive emulsifier(LRP-10)was used to replace the traditional non-reactive emulsifier.VV-10 was a tertiary carbon monomer and the emulsion was prepared by semi continuous seed emulsion pre emulsification.The effects of emulsifier type,dosage and VV-10 dosage on the gel rate,water absorption,water resistance,calcium ion stability and adhesion of emulsion and coating were investigated.The structure and corrosion resistance of emulsion and coating were characterized by FTIR,TEM,particle size,contact angle and electrochemical test,and the mechanism of corrosion resistance was analyzed.The results showed that when the LRP-10 dosage was 2%,the distribution ratio was seed emulsion:the pre emulsion was 1.5∶0.5 and the dosage of VV-10 was 10%,the water absorption of the film decreased from 18.87% to 2.18%.After the water test 168h,the coating slightly whitened,but it quickly resumed.The contact angle of coating water increased from 50.5°to 85.5°and the coating impedance increased from 1.40069×10^(6)Ω·cm^(2) to 7.38137×10^(8)Ω·cm^(2).The minimum corrosion current density was 1.2268μA/cm^(2) and the most positive corrosion potential was-0.19753V.The reactivity and passivation of LRP-10 and hydrophobic and barrier effects of VV-10 had synergistic effects,which greatly improved the anticorrosion performance of waterborne acrylic coatings.