氧化还原引发剂对丙烯酸酯乳液性能及聚合机制的影响

以过硫酸钾(KPS)和亚硫酸氢钠(NaHSO3)为自由基聚合体系的氧化-还原型引发剂,以十二烷基硫酸钠(SDS)和脂肪醇聚氧乙烯醚硫酸钠(AES)为阴/非离子型复合乳化剂,制备甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和甲基丙烯酸(MAA)共聚物乳液。研究了引发剂种类及用量对该乳液性能及聚合过程等影响,探讨并提出了酸性条件下丙烯酸酯乳液体系的新型引发机制。结果表明:在其他条件保持不变的前提下,当m(KPS):m(NaHSO3)=1.00:0.45、w(KPS+NaHSO3)=0.6%时,乳液的单体转化率(98%)和黏度(5.900 Pa.s)相对最高,反应时间(2.0 h)相对较短且初始聚合温度(60℃)相对最低,此时乳液质量最稳定。

Influences of redox initiator on properties and polymerization mechanism of acrylate emulsion

With potassium persulfate(KPS) and sodium bisulfite(NaHSO3) as oxidant-reducer initiator of free radical polymerization system,sodium dodecyl sulfate(SDS) and sodium fatty alcohol ether sulfate(AES) as anionic-nonionic emulsifier,an acrylate copolymer emulsion based on methyl methacrylate(MMA),butyl acrylate(BA),methacrylic acid(MAA) was prepared.The influences of initiator types and contents on properties and polymerization process of the emulsion were investigated,and a new type polymerization initiating mechanism was discussed and presented for the acrylate emulsion system under acidic condition.The results showed that the emulsion had reversely maximal monomer conversion rate(98%) and viscosity(5.900 Pa·s),reversely shorter reaction time(2.0 h),reversely lowest incipient polymerization temperature(60 ℃) and jarlessest quality when mass ratio of m(KPS):m(NaHSO3) was 1.00:0.45 and total mass fraction of KPS and NaHSO3 was 0.6%.