Agglomerating Agent Emulsions Synergistically Stabilized by Surfactants and SiO2 Nanoparticles: Stability, Mechanism, and Applications for PBL Agglomeration

The stability of agglomerating agent is an important parameter to evaluate its value, which is of great significance for its subsequent transportation, storage, and practical application. In this study, a highly stable agglomerating agent synergistically stabilized by sodium dodecyl sulfate (SDS) and SiO2 was synthesized. The stabilization mechanism of the agglomerating agent and its agglomeration effect on polybutadiene latex (PBL) were studied. First, the mean particle size, particle size distribution, interfacial tension, and viscosity of the agglomerating agent emulsion stabilized by SDS/SiO2 has been investigated and compared with those of conventional emulsion stabilized by SDS. The results show that when the SDS concentration is lower than 0.125%, the presence of SiO2 can significantly increase the anticoagulation ability of agglomerating agent particles in the polymerization process. Furthermore, noting that agglomerating agent emulsions stabilized by SDS/SiO2 exhibited high stability even pH, centrifugation, storage, and temperatures changed in wide range. In addition, the stability of the agglomerating agents synergistically stabilized by surfactants and SiO2 nanoparticles is better than using them alone. Then, the stability mechanism of SiO2 in the agglomerating agent was investigated. The results revealed that the SiO2 particles are tightly adsorbed on the surface of the agglomerating agent particles through hydrogen bonding and play a physical isolation role. Finally, the 100 nm PBL was enlarged to 469 nm by a synthetic agglomerating agent. Surprisingly, the SiO2 particles show excellent physical isolation role, not only in agglomerating agent but also in agglomerated PBL. Our findings provide novel insights into the synthesis of highly stable agglomerating agent and improve the practical application significance of subsequent PBL agglomerations and ABS properties.