苯乙烯-丙烯酸丁酯分散共聚合动力学

用分散聚合法制备了表面光滑、粒径均匀的聚苯乙烯-丙烯酸丁酯微球,研究了各种参数变化对聚合转化率-时间曲线的影响并得到苯乙烯和丙烯酸丁酯的分散聚合动力学方程。结果表明,在所考察的范围内,初始单体中丙烯酸丁酯的物质的量分数超过20%以上时,总转化率明显降低;在60℃~75℃之间随温度上升,总转化率增大,但80℃时反而减小,并随着醇水比的降低、引发剂用量的增大而增大,稳定剂的浓度对其影响甚小;在所考察的范围内,苯乙烯和丙烯酸丁酯的分散聚合动力学方程为Rp=k.exp(38194/RT)St/BA]0.7029m(EtOH)/m(EtOH+H2O)]-4.138AIBN]0.3845,其表观活化能Ea为38.194 kJ/mol。

Kinetic of Styrene-Butylacrylate Dispersion Copolymerization

Mnodisperse micron-size polystyrene-butyl acrylate microspheres with smooth spherical surface were prepared by dispersion polymerization.The dependence of conversion-time on different parameters was studied,moreover,the kinetic equation of dispersion copolymerization was also obtained.The results show that when the monomer molar ratio BA/St is higher than 20/80 the total conversion decreases significantly,the total conversion increases with the temperature increasing from 60℃ to 75 ℃ and decreases when 80 ℃,the total conversion increases with the decrease of EtOH/H2O ratio and with the increase of initiator concentration.The dependence of total conversion on stabilizer concentration was not pronouncedly.The kinetic equation of the polymerization can be expressed as: Rp=k·exp(38194/RT)0.7029m(EtOH)/m(EtOH+H2O)]-4.1380.3845(60 ℃～75 ℃).The overall activation energy for the rate of polymerization is 38.194 kJ/mol.