The Preparation Of Polystyrene Beads By Microchannel Suspension Polymerization

Polystyrene beads with diameters of 0.3～0.8 mｍ can be employed as frames of ion exchange(IE)resins and adsorption(AD)resins.Recently,with the development of IE and AD technologies,resins with a controlled size and narrow size distribution are highly desirable.Owing to their wide size distribution,the polystyrene beads prepared by conventional suspension polymerization need to be screened to meet the requirements of applications resulting in a serious waste of raw materials and an increase of the production cost.Therefore,how to manufacture uniform beads is an issue in the area of functional polymer.In this work,a microchannel suspension polymerization was proposed to prepare uniform polystyrene beads.In the first stage,we built up a pore-plate microchannel dispersing apparatus and revealed the effects of operation parameters on the size and size distribution of monomer droplets.In the second stage,the monomer droplets were polymerized in a stirred batch reactor to form solid beads.The effects of the agitator speed and the temperature of the continuous phase on the size and size distribution of beads were investigated.The experimental results indicated that,to obtain uniform monomer droplets,the extrusion pressure difference across the pore-plate should be between the critical jetting pressure and the maximum pressure.The component of the continuous phase influenced significantly on the uniformity of the droplets.The size distribution of polystyrene beads prepared from the microchannel suspension polymerization was much narrower than that of beads prepared from conventional process.