TRIBOELECTRIC CHARGE CONTROL OF POLYMER MICROSPHERES BY SURFACE MODIFICATION USING HETEROCOAGULATION

A new technique to control the triboelectric charge (TEC) of polymer microspheres is proposed. Polymer microspheres (PMs) were prepared by three-component suspension copolymerization of styrene (S), 2-ethylhexyl methacrylate (EHMA) and dimethylaminoethyl methacrylate (DM). Emulsion particles (EPs) for surface modification were prepared by emulsifier-free three-component emulsion copolymerization of S, EHMA and sodium styrene sulfonate (NaSS). PMs were covered with EPs by a process similar to the 'stepwise heterocoagulation technique' (Okubo, M., He, Y. & Ichikawa, K., Colloid Polym. Sci., 269 (1991) 125). The value of TEC of modified microspheres varied from - 30 muC/g to - 60 muC/g with increasing NaSS content of EPs from 3 wt% to 6 wt%, though unmodified particles had small values of TEC. This fact suggests that the surface modification used can lead to the preparation of particles having a desired TEC.