聚(VAc/AA)的合成及在乳液聚合中的应用

Synthesis of poly(vinyl acetate-acrylic acid) and its application in emulsion polymerization

采用无皂乳液聚合方法，合成聚（醋酸乙烯／丙烯酸）[P（VAc／AA）]共聚物，研究了加料方式、单体配比对乳液稳定性的影响。结果表明，mVAc：mAA=（0．5～2.5）：1时，采用分段聚合工艺，共聚乳液性能良好；pH值越高，乳液越稳定。将P（VAc／AA）共聚乳液作为高分子乳化剂用于醋酸乙烯的乳液聚合，对乳液性能进行表征。结果表明，采用P（VAc／AA）为乳化体系，与传统的OP-10／SDS乳化体系相比，其稀释稳定性提高，胶膜的吸水性下降，粒径、黏度和压缩剪切强度均降低。

The poly（ vinyl acetate-acrylic acid） P（VAc/AA） emulsion was synthesized with hydrophilic acrylic acid and lipophilic vinyl acetate by the soap-free emulsion polymerization. The effect of the charging method and the ratio of monomer on emulsion stability was studied, the resulted showed that using multi-stage emulsion polymerization the polymerization stability and storage stability were better when the mass ratio of vinyl acetate and acrylic acid was （0.5 - 2.5 ） ： 1 ; the higher pH value was in the emulsifier, the better storage stability was in room temperature. P （VAc/AA） emulsion with hydrophilic carboxyl groups from acrylic acid and lipophilic vinyl acetate chain units from vinyl acetate was a the polymeric emulsifier, which was used in vinyl acetate emulsion polymerization. The results indicated that,in comparison with the conditional OP-10/SDS emulsifier system, when using P（VAc-AA） as the emulsifer the dilution stability of emulsion was enhanced, the water absorption of film, the particle size and the viscosity decrease, and the compress shear strength reduced.