作　　者： ; ; ; ; ;

机构地区： 华南理工大学化学与化工学院化学工程研究所

出　　处： 《高校化学工程学报》 2007年第4期614-620,共7页

摘　　要： 以甲基丙烯酸甲酯（MMA）和丙烯酸丁酯（BA）为反应单体合成丙烯酸酯乳液,研究了半连续式乳液聚合过程中反应温度（T）、引发剂浓度（[I]）和乳化剂浓度（[E]）对聚合动力学的影响,并着重分析了不同[E]时体系的成核机理和整个聚合过程中粒径及其分布的演变规律。实验结果表明：单体转化率随T、[I]和[E]的增大而增大,体系的表观活化能Ea=132.43kJ·mol^-1,聚合反应速度Rp∝[I]^0.42;当[E]〉1.0×10^-2mol·L^-1时,Rp∝[E]^1.28,体系遵循胶束成核机理及其聚合规律;而当[E]〈1.0×10^-2mol·L^-1时,Rp∝[E]^0.17,体系以均相成核为主要成核方式。此外,乳胶粒径及其分布规律进一步验证了体系在不同[E]时具有不同的成核机理,当[E]为1.91×10^-2mol·L^-1时其成核阶段为0-10min;而当[E]为9.57×10^-4mol·L^-1时其成核阶段为0-15min。 An acrylate emulsion was prepared with methyl methacrylate （MMA） and butyl acrylate （BA） as monomers. The influences of the reaction temperature （T）, the concentration of initiator （[I]） and emulsifier （[E]） on the polymerization kinetics for semi-continuous emulsion polymerization were studied, and the nucleation mechanism and evolvement regulation of emulsion particle size and size distribution were investigated during the whole process of polymerization with various [E]. The experimental results show that the monomer conversion increases with increasing T, [I] and [E], The kinetic equation was obtained with the apparent activation energy Ea =132.43 kJ·mol^-1. The relation of polymerization rate Rp and [I] is Rpo∝ [I]^0.42, It was also found that, when [E] 〉1.0×10^-2 mol·L^-1, the relationship between Rp and [E] is Rp∝[E]^1.28 and the nucleation mechanism of the system is ＂micellar nucleation＂, while when [E]〈 1.0×10^-2 mol·L^-1, the relationship is Rp∝ [E]^0.17 and the nucleation mechanism is ＂homogeneous nucleation＂ mainly. Furthermore, the found evolvement regulation of emulsion particle size and its distribution identify that there are different nucleation mechanisms with different [E], such as the time of nucleation process locates between 0 to 10 min when [E] equals to 1.91× 10^-2 mol·L^-1, while when [E] equals to 9.57×10^-4 mol·L^-1, the time of nucleation process locates between 0 to15 min.

关 键 词： 半连续式乳液聚合 聚合速率 成核机理 粒径及其分布

领　　域： [化学工程] [化学工程]