通过硫醇-烯点击反应在聚乙酸乙烯酯(PVAc)基核壳乳胶粒表面接枝硫醇基团,并在乳胶粒合成后期采用预乳化法加入双键活性单体,制备了硫醇化PVAc基复合乳液。研究表明:制备的乳胶粒粒径在200nm左右,表面修饰的巯基官能团能够与双键活性单体在紫外光照射下发生硫醇-烯点击反应,实现快速成膜固化;复合乳液稳定性优良,储存期可达60d以上。将复合乳液用于木材光固化涂饰时,活性单体三羟甲基丙烷三丙烯酸酯(TMPTA)与二硫苏糖醇(DTT)质量比为3:1时复合乳液仅需12s即可完全固化;调控DTT与活性单体的比例可改善漆膜性能,当TMPTA与DTT质量比为4:1时,硫醇化PVAc基光固化复合乳胶膜的最大应力达到2.17MPa,应变为0.78%,漆膜光泽度、粗糙度、铅笔硬度分别为12.3°、2.36μm和4H。

DL-dithiothreitol (DTT) was grafted onto the surface of polyvinyl acetate (PVAc)-based core-shell latex through the thiol-ene click reaction.Meanwhile,double bond active monomers were added by the pre-emulsification method at the late stage of latex synthesis to prepare thiol-modified PVAC-based composite emulsions.The results showed that the particle size of the latex was about 200nm,and the surface modified thiol functional groups could undergo thiol-ene click reactions with the double bond active monomers under UV irradiation,thereby achieving rapid film formation and curing.The composite emulsion demonstrated excellent stability and a storage period of more than 60 days.When the composite emulsion was applied for UV-curing wood coating,it could be completely cured in just 12 seconds at a mass ratio of 3:1 between the reactive monomer trimethylolpropane triacrylate (TMPTA) and DL-dithiothreitol (DTT).The film performance could be improved by regulating the ratio of mercaptans to active monomers.When TMPTA:DTT mass ratio was 4:1,the composite emulsion UV-cured latex film exhibited a maximum stress of 2.17MPa and a strain of 0.78%.Meanwhile,the glossiness,roughness and pencil hardness of the coating were 12.3°,2.36μm and 4H,respectively.