有机硅氧烷改性醋酸乙烯酯-丙烯酸酯乳液的合成与性能

采用种子乳液聚合,引入乙烯基三甲氧基硅烷(A-171),以十二烷基苯磺酸钠(DSB)和壬基酚聚氧乙烯(20)醚(OP-10)作复合乳化剂,以过硫酸钾(KPS)为引发剂,在反应温度为78±2℃条件下,合成了A-171改性醋酸乙烯酯(VAc)-丙烯酸酯共聚乳液。实验采用单体滴加工艺,考察了配方中丙烯酸丁酯(BA)、甲基丙烯酸(MAA)和A-171用量对共聚物性能和乳液聚合过程的影响,并用红外光谱仪(FTIR)、粒度仪和差示量热扫描仪(DSC)对共聚物的结构及性能进行了表征。结果表明,引入w(BA)=10%~15%(相对于配方中单体总质量,下同)、w(MAA)=4%、w(A-171)=1%到VAc-丙烯酸酯共聚物乳液中,共聚物乳液涂膜的吸水率<5.0%,耐寒性通过10个循环,60℃加速贮存稳定性>100 d。

Synthesis and Properties of Organosiloxane Modified Vinyl Acetate/acrylate Copolymer Emulsion

Using anionic emulsifier DSB and nonionic emulsifier OP-10 as composite emulsifier and potassium persulfate as initiator,a new kind of vinyl acetate/acrylate copolymer emulsion modified by organosiloxane(named A-171) were synthesized by seed emulsion polymerization at 78±2 ℃.With mixed-monomer adding techniques,the effects of butyl acrylate(BA),methacrylic acid(MAA) and A-171 on the properties of the emulsion and the stability of emulsion polymerization were examined.The structure and properties of copolymer emulsion were analyzed by particle size analyzer,FTIR and DSC.Experimental results indicate that the properties of copolymer emulsion is excellent with 10%~15% BA and 4% MAA(based on total monomers in the formulation).The macromolecules of organosiloxane had been copolymerized with vinyl acetate/acrylate monomers thoroughly,and there is a great improvement in properties of emulsion,especially waterproofing,freeze resistance and depositing stability.