摘要
以甲基丙烯酸甲酯（MMA）和丙烯酸丁酯（BA）为主要单体，选择加入合适的有机硅单体及纳米SiO2，采用核壳乳液聚合和无皂乳液聚合制备了具有硬核软壳结构的有机硅／纳米SiO2改性丙烯酸酯乳液，研究了有机硅用量、TEOS用量及温度等因素的影响，采用TEM、FT-IR和TGA等测试手段对乳液及其膜进行了表征。结果表明，有机硅单体选择A-174且用量为总单体量的2％，与30％壳单体一起预乳化后加入到体系中，纳米SiOz的前驱体正硅酸四乙酯用量为1％，反应温度为75-78℃，搅拌速度为200r／min的条件下，可得到乳液平均粒径为160．4nm、单体转化率达96．2％、固含量达53％的稳定有机硅／SiO2改性聚丙烯酸酯复合乳液。复合改性乳液的TEM显示其具有明显的核壳结构；FT-IR表明有机硅成功地接枝到丙烯酸酯分子链上；TGA曲线表明改性后的丙烯酸酯乳胶膜热稳定性得到提高。
Polyacrylate emulsion with hard core and soft shell structure was synthesized by soap-free emulsion polymerization and core-shell emulsion polymerization with MMA and BA as the main raw material, choosing the appropriate organic silicon monomer, appropriate reaction temperature and different form nano SiO2 modified polyacrylate emulsion in the process of polymerization. The polymer structure were characterized by differential scanning calorimeter （DSC）, transmission electron microscopy （TEM）, Fourier transform infrared spectoscopy （FT-IR） and thermo- gravimetric analysis （TGA）. The results show that 2% A-174 organic silicon was dropped into the system with 30% shell monomer after pre-emulsion, SiO2 nanoparticles were obtained from 1% TEOS via sol-gel process, the reaction temperature was 75-78 ℃ and the stirring speed was 200 r/min. We obtained the stable silicone/nano-SiO2 modified polyacrylate composite emulsion with high solid content of 53%, high conversion rate of 96.2% and the ave-rage particle size of 160.4 nm. TEM showed that composite ernuision particles exhibited an apparent core-shell structure FT- IR confirmed the organic silicon were effectively grafted to the polyacrylate molecular chaiN TGA confirmed the composite emulsion film had better thermal stability compared with those of conventional polyacrylate emulsion.
基金
广东省高校科技创新重点项目(cxzdl128)
轻化工清洁生产工程技术研究中心开发课题基金
江门市产学研专项资金
