Abstract: To adjust the size and size distribution of miniemulsified butyl acrylate（BA）droplets containing nanometer silica particles，the influences of the composite of miniemulsification system and the ultrasonic conditions on the size and size distribution of droplets were investigated.It was found that there existed critical ultrasonic power and time for achieving a stable size and size distribution of droplets.The droplets size decreased as the concentration of sodium dodecyl sulfate（SDS）increased，while the concentration of hexadecane had no significant influence on the droplet size.The droplet size increased and the droplets size distribution widened as the mass fraction of silica in BA dispersion，and the BA dispersion/water mass ratio increased.It was confirmed that the existence of nanometer silica particles in BA had a certain influence on the miniemulsification of butyl acrylate as the nanometer silica particles consumed a part of the ultrasonic power and changed the physical characteristics of the disperse phase.When the storage and polymerization temperatures were below 65℃，stable miniemulsion and corresponding poly（butyl acrylate）/nanosilica composite latex could be obtained.

摘要： 为了调控含纳米SiO₂的丙烯酸丁酯细乳化后液滴的粒径及粒径分布，研究了细乳化体系组成和超声分散条件对细乳化液滴粒径及粒径分布的影响.发现存在使细乳化液滴粒径及粒径分布趋于稳定的临界超声功率和超声时间;随着十二烷基硫酸钠（SDS）乳化剂浓度增加，液滴粒径减小，而十六烷浓度对液滴粒径影响较小;随着BA分散液中纳米SiO₂质量分数和BA分散液/水质量比的增加，液滴平均粒径增大，粒径分布变宽，这是由于纳米SiO₂粒子吸收了部分超声波能量，同时改变了分散相特性所致.当放置或聚合温度在65℃以下时，细乳化液或相应的聚丙烯酸丁酯/纳米SiO₂复合乳胶能稳定分散.