NP/DBS混合乳化剂对苯丙乳液性能的影响

分别采用丙烯酸丁酯和苯乙烯作为软硬单体，NP和DBS的混合乳化剂作为乳化体系，采用过硫酸钾作为引发剂，并引入功能性单体甲基丙烯酸，用半连续种子乳液聚合工艺来制备苯丙乳液．在聚合过程中改变加入的乳化剂量．研究了乳化剂对苯丙乳液的平均粒径、稳定性、吸水率、粘度和流变性等性质的影响．研究结果表明随着乳化剂用量的增大，乳液胶粒的平均粒径减小，而乳液的粘度和胶膜的吸水率却增大．乳液的稳定性受乳化剂中非离子乳化剂和阴离子乳化剂的质量配比影响较大，而乳液的流变性则与乳化剂的浓度无关．并对乳化剂对乳液性质的影响原因进行解释和分析．因此，在制备不同用途的苯丙乳液时，必须要严格控制乳化剂的浓度及配比．

Influence of NP/DBS Mixed Emulsifiers on the Properties of Styrene-Acrylate Emulsions

Styrene and butyl acrylate are used as hard monomer and soft monomer respectively. The mixture of nonlyphenol ethxoylates(NP) and dodecylben-zenesulphonic acid-(6)-sodium salt(DBS) is used as emulsifiers and Potassium persulfate(KPS) is employed for the initiator. And functional monomer-methacrylic acid(MAA) is introduced to prepare styrene-acrylate emulsions with semi-continuous seeded emulsion polymerization in which the concentration of the emulsifiers is varied. The influence of the emulsifiers(NP and DBS) on the properties of styrene-acrylate emulsions such as average particle size, stability, water absorption, viscosity and rheology are studied. The results show that an increase of the emulsifier concentration leads to dispersions with smaller particles, higher viscosities and water absorption. The stability of the latex is influenced with the ratios of the nonionic emulsifiers to anionic emulsifiers. However, the rheology of the latex is not affected by the concentration of the emulsifiers. The scientific and reasonable explanation and analysis is given. Therefore, the concentration of emulsifiers and their ratio must be strictly controlled when styrene-acrylate emulsions for different uses are prepared.