ONLINE TERPOLYMER COMPOSITION CONTROL IN SEMICONTINUOUS EMULSION POLYMERIZATION

A closed-loop strategy for terpolymer composition control in semiconti nuous emulsion polymerization of high solids content systems is presen ted. This strategy is based on a nonlinear adaptive controller that ca lculates the flow rate of the more reactive monomers to be added into the reactor to produce a terpolymer of a given composition. The nonlin ear adaptive controller is based on a simplified mathematical model of the process that includes the on-line estimation of an adjustable par ameter. The addition of a conventional feedback proportional-integral (PI) controller to the prediction of the nonlinear controller was stud ied by simulation. It is shown that the contribution of the PI control ler is negligible. The controller was checked by computer simulation a nd also experimentally verified during the semicontinuous emulsion ter polymerization of high solids content (55 wt. %) of vinyl acetate, met hyl methacrylate and butyl acrylate.