氧化石墨烯/氟硅丙-苯胺复合乳液的制备及其涂层的防腐蚀性能

Preparation of graphene oxide/organofluorine-silicone modified acrylate-aniline composite emulsion and anticorrosive properties of its coating

[目的]为了提高丙烯酸酯乳液涂层的防腐蚀性能,需在乳液聚合时引入功能单体,并在乳液中添加功能填料,以阻止腐蚀介质的侵入。[方法]以甲基丙烯酸十二氟庚酯(DFMA)、乙烯基三甲氧基硅烷(VTMS)及苯胺(Ani)为功能单体,通过无皂乳液聚合法制备了氟硅丙烯酸酯-苯胺共聚乳液(FSiAc-Ani);再以木质素磺酸钠为改性剂,制备了磺酸改性氧化石墨烯(SO_(3)H-GO)。在Q235钢表面制备了磺酸改性氧化石墨烯/氟硅丙-苯胺共聚乳液(SO_(3)H-GO/FSiAc-Ani)复合防腐蚀涂层。探讨了改性GO的种类、用量及不同的复合方法对复合涂层性能(尤其是防腐蚀性能)的影响。[结果]当SO_(3)H-GO用量为1.25%(相对于FSiAc-Ani乳液的质量)时,SO_(3)H-GO/FSiAc-Ani复合涂层的干、湿附着力均为0级,吸水率为1.78%,水接触角为96.56°,低频阻抗模值最大,腐蚀电位最正,腐蚀电流密度最小。[结论]相比于单纯共混的硅烷改性氧化石墨烯/聚苯胺/氟硅丙乳液(Si-GO/PANI/FSiAc)和磺酸改性氧化石墨烯/聚苯胺/氟硅乳液(SO_(3)H-GO/PANI/FSiAc)复合涂层,SO_(3)H-GO/FSiAc-Ani复合涂层对Q235钢具有更优异的防腐蚀性能。

[Introduction]To improve anticorrosive performance of acrylate emulsion coatings,it needs to introduce functional monomer or filler into the emulsion for preventing the invasion of corrosive medium.[Method]Organofluorine-silicone modified acrylate aniline copolymer emulsion(FSiAc-Ani)was prepared by emulsifier-free emulsion polymerization with dodecafluoroheptyl methacrylate(DFMA),vinyl trimethoxysilane(VTMS),and aniline(Ani)as functional monomers.Sulfonated graphene oxide(SO_(3)H-GO)was prepared with sodium lignosulfonate as modifier.An anticorrosive SO_(3)H-GO/FSiAc-Ani composite coating was prepared with the FSiAc-Ani emulsion as binder and SO_(3)H-GO as filler on the surface of Q235 steel.The effects of different modified GOs and their dosages as well as different preparation methods on the anticorrosion performance of the composite coatings were studied.[Result]The SO_(3)H-GO/FSiAc-Ani composite coating prepared with 1.25%of SO_(3)H-GO with respect to the FSiAc-Ani emulsion had a 0-grade adhesion under both dry and wet conditions,a water absorption rate of 1.78%,a water contact angle of 96.56°,the largest low-frequency impedance magnitude,the most positive corrosion potential,and the smallest corrosion current density.[Conclusion]The SO_(3)H-GO/FSiAc-Ani composite coating has better anticorrosion performance for Q235 steel as compared with the SO_(3)H-GO/PANI/FSiAc and Si-GO/PANI/FSiAc composite coatings prepared simply by blending the FSiAc emulsion and polyaniline(PANI)with SO_(3)H-GO or silane-modified GO(Si-GO).