![]() Usually, the monomer conversion is completed unlike in bulk polymerization, and the initiator used in this is monomer-soluble. One of the most common suspending agents is polyvinyl alcohol (PVA). To prevent this, the mixture is carefully stirred or a protective colloid is often added. During this process, there is often a possibility of these monomer droplets sticking to each other and causing creaming in the solution. The primary advantage of suspension polymerization over other types of polymerization is that a higher degree of polymerization can be achieved without monomer boil-off. While choosing a liquid phase for suspension polymerization, low viscosity, high thermal conductivity and low-temperature variation of viscosity are generally preferred. The liquid phase outside these droplets help in better conduction of heat and thus tempering the increase in temperature. The individual monomer droplets can be considered as undergoing bulk polymerization. The monomer droplets (size of the order 10-1000 μm) are suspended in the liquid phase. Suspension polymerization is a heterogeneous radical polymerization process that uses mechanical agitation to mix a monomer or mixture of monomers in a liquid phase, such as water, while the monomers polymerize, forming spheres of polymer. Light microscopic picture of a PMMA-copolymer, made by suspension polymerization SEM-Picture of PMMA-particles, that started to coalesce during suspension polymerization, close to a single bead SEM-picture of a Pac-Man shaped PMMA-copolymer particle, made by suspension polymerization ![]() Note 2: Monomer or monomer-solvent droplets in suspension polymerization haveĭiameters usually exceeding 10 μm. Note 1: In suspension polymerization, the initiator is located mainly in the monomer phase. In a continuous phase that is a nonsolvent for both the monomer and the formed polymer. Polymerization in which polymer is formed in monomer, or monomer-solvent droplets
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