细乳液聚合制备有机硅/丙烯酸酯乳液及其性能

利用细乳液聚合技术设计并制备了不同有机硅含量的有机硅改性丙烯酸酯共聚物稳定乳液.通过细乳液共聚合反应在丙烯酸酯类聚合物主链上引入硅氧烷侧基，该基团水解后与羟基硅油缩合，引入聚硅氧烷接枝链.研究表明：（1）γ-甲基丙烯酰氧丙基三甲氧基硅烷(MPMS)比乙烯基三乙氧基硅烷(VTES)更适合在本体系中用作共聚有机硅单体;（2）聚合过程中，乳液稳定，凝聚物很少;（3）羟基硅油能较好地接枝到丙烯酸酯聚合物主链上，接枝率在50%左右;（4）有机硅的引入减少聚合物涂层的吸水率，表面的水接触角也明显增大，显示出较强的疏水特性.有机硅含量在10%（质量）时，聚合物涂层即可显示很好的憎水特性，随着有机硅含量进一步提高，憎水特性可进一步提高，聚合物涂膜吸水率可低至5%，水接触角可高达105°.

Synthesis and properties of alkoxysilane-modified acrylic latex via miniemulsion polymerization

A series of stable alkoxysilane-modified acrylate latexes with various alkoxysilane fractions were synthesized by miniemulsion polymerization.A small fraction of alkoxysilane side groups were incorporated into acrylic main chains via copolymerization.The hydroxyl oligomer alkoxysilane was grafted to the main chains via the condensation reaction of the hydroxyl groups with hydrolyzed alkxoysilane groups.It was found that：(1)γ-methacryl oxypropyl trimethoxysilane (MPMS) was a better alkoxysilane comonomer than vinyltriethoxysilane (VTES)in terms of colloid stability during polymerization and the hydrophobic property of the resulted polymer coating;(2)when MPMS was used, the colloid stability was very good either during polymerization or in storage;(3)the oligomer alkoxysilane was grafting onto with a grafted degree around 50%;(4)the oligomer alkoxysilane dramatically increased the hydrophobic property of the resulted coating.The water contact angle increased from 75° to 95° with 10%(mass) oligomer alkoxysilane and further up to 105° with 20%(mass) oiligomer alkoxysilane.