Influences of maleic reactive surfactants with different EO chain lengths on the properties of the acrylate latices

Three maleic reactive surfactants with different oxyethylene (EO) units (5, 9 and 15) were synthesized and used to prepare the soap-free acrylate latices with methyl methacrylate, butyl acrylate, and hydroxypropyl acrylate as monomers through the polymerization of pre-emulsifying seed emulsion and semi-continuous dropping process. Effects of EO chain lengths on the properties of the latices and their films were investigated. The results showed the polymerization using maleic reactive surfactant with 9 EO units could achieve the highest monomer conversion and the copolymers with highest M w were obtained. The viscosity of latices decreased and their chemical stabilities and particle sizes increased with the increase of EO chain lengths. The EO chain lengths slightly influenced the pencil hardness and adhesion of the latex films, but the shorter the EO chain lengths were, the better were these properties. The amount of maleic reactive surfactants had effects on the properties of the acrylate latices as well. In addition, the results from TEM showed that the latex particles were irregular and there were some “caves” in the particles. It was considered that the particles were formed due to the coil and entanglement of the growing polymer chains in the aqueous phase.