用于可再分散乳胶粉的阳离子苯丙乳液的合成

采用种子乳液聚合法,以十六烷基三甲基溴化铵(CTAB)为乳化剂,偶氮二异丁眯盐酸盐(AIBA)为引发剂,引入亲水性阳离子单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)及功能性单体丙烯酰胺(AM)〔m(DMC)∶m(AM)=1∶1〕来制备用于可再分散乳胶粉的阳离子苯丙乳液。探讨了聚合反应温度、乳化剂用量、引发剂用量、种子单体用量、阳离子单体用量等对乳液及可再分散乳胶粉性能的影响。确定最佳配方和工艺条件为:聚合反应温度为(80±2)℃、DMC添加量为2%(以主要聚合单体质量计,下同)、CTAB用量为2%(以单体总质量计,下同)、AIBA用量为0.53%(以单体总质量计,下同)、种子单体用量为10.0%(以单体总质量计,下同)。在该工艺条件下,合成的阳离子苯丙乳液粒径大小和分布适中、性能稳定,由其所制得的可再分散乳胶粉含水率低、平均粒径小、再分散性优良。

Synthesis of Cationic Styrene-acrylic latex Used for Redispersible latex Powder

The cationic styrene-acrylic latex used for redispersible polymer powder was prepared by the method of seeded emulsion polymerization by using cetrimonium bromide(CTAB) as emulsifier,azobisisobutryamide chloride(AIBA) as initiator,and 2-(methacryloyloxy)ethyl]trimethyl-ammonium chloride(DMC) as hydrophilic cationic monomer and acrylamide(AM) as functional monomer with the mass ratio of DMC to AM being 1:1.The effects of polymerization temperature,the amount of emulsifier,initiator,seed monomer,and cationic monomer on the polymerization reaction system and the properties of latex and redispersible latex powder were investigated.The optimum formula and process conditions are that the polymerization temperature is(80±2) ℃,and the amount of DMC based on main polymerization monomer is 2%,the amount of CTAB,AIBA and seed monomer based on total monomers is 2%,0.53%,10% respectively.Under such optimum conditions a uniform and stable latex with small particle size and narrow particle size distribution could be obtained.Redispersible latex powder made from this latex has low water content and small average particle size,and also exhibits good redispersibility.