APS-AIBN引发体系对苯丙乳液聚合过程及涂层性能的影响

Influence of APS-AIBN Initiator Composite on the Polymerization Process and Coating Properties of Styrene-Acrylic Emulsions

分别考察了过硫酸铵(APS)、偶氮二异丁腈(AIBN)以及二者复配引发体系对苯丙乳液成核过程、粒径及分子质量分布、聚合稳定性以及乳液涂层性能的影响。结果表明:APS引发体系以"胶束成核"为主,AIBN体系同时存在"胶束成核"和"单体液滴成核"两种方式。"单体液滴成核"在聚合过程中易暴聚导致粒径和分子质量分布变宽,同时可避免亲水单体自聚,提高涂层耐水性。APS-AIBN复配可实现两种成核方式优势互补,当AIBN占总引发剂质量的60%,引发剂占单体总质量的1.5%时,凝胶率为0.95%,转化率为98.25%,涂层耐水性优于传统APS引发体系。

The influences of initiating systems on the emulsion nucleation process,particle size distribution,weight distribution,stability of emulsion polymerization and coating properties were discussed,with ammonium persulfate（APS）,azodiisobutyronitrile（AIBN）and their combinations.The results were as follows：＂micellar nucleation＂ was the main mechanism in APS initiating system;however,＂micellar nucleation＂ and ＂monomer drops nucleation＂ were both existed in AIBN initiating system.＂Monomer drops nucleation＂ usually caused flash polymerization,which widened the particle size and weight distribution.Due to the direct contact mode between butyronitrile radicals and monomers,the self-polymerization of hydrophilic monomers could be inhibited,leading to a better water resistance.The complemental advantage of two types nucleation modes could be achieved,using the combination of APS and AIBN.When AIBN accounted for 60%of the total initiator mass,and the initiator accounted for 1.5% of the total mass of monomers,the coagulation ratio was 0.95%,the conversion was 98.25%,and the coating demonstrated better water resistance than those coating prepared in traditional APS initiating system.