Surface coagulum reactor

The failure of latex stability,and the resultant flocculation of the latex par tides, may cause the formation of coagulum that is recovered from the latex after polymerization as well as a buildup on the reactor surfaces. Moreover, the inherent instability of the latex may also cause flocculation during storage or transportation. 

The coagulum deposited on the reactor surfaces may be the result of polymerization in large monomer drops or a separate monomer layer, or it may be the result of polymerization of the monomer in the vapor space above the latex or a surface polymerization on the walls and roof of the reactor. Polymerization in the vapor space of the reactor will form solid polymer in the form of particles which may stick to the reactor surfaces or fall into the latex in the later case, these particles serve as nuclei for the formation of coagulum. Polymerization of monomer on the reactor surfaces will form solid particles that become swollen with monomer and grow by flocculation of the latex particles. The surface polymerization can be related to the smoothness of the reactor surface the smoother the surface, the lesser the tendency for surface polymerization and formation of coagulum. 

Coagulum is formed in many emulsion polymerizations, from the smallest laboratory size to the largest production reactors. It is observed in many forms, from a single lump of polymer with little or no fluid latex to tiny sand-like grains suspended in an otherwise stable latex. Usually, it is found as lumps in the latex or deposited on the reactor surfaces. The type and amount of coagulum formed depends upon the polymer system and the polymerization recipe and technique. Two mechanisms are proposed for the formation of coagulum (i) a failure of the stability of the latex, giving rise... 

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