On-line monitoring of methyl methacrylate–vinyl acetate emulsion copolymerization

✍ Scribed by A. M. Santos; G. Févotte; N. Othman; S. Othman; T. F. McKenna

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 293 KB
• Volume: 75
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(20000328)75:13<1667::aid-app12>3.0.co;2-2

✦ Synopsis

An adaptive calorimetric method, coupled with state estimators for emulsion copolymerization, is shown to provide accurate, on-line information on the evolution of the composition and kinetics of an emulsion copolymerization. This method was evaluated for the emulsion copolymerization of methyl methacrylate-vinyl acetate (MMA-VAc) under nonisothermal conditions. In addition to providing on-line estimates of the number of moles of each polymerizing species in the reactor, the state estimator provides a value for a lumped kinetic parameter proportional to the product of n N p . This information can be combined with off-line measurements to study the evolution of polymerization kinetics and to explain the trends observed for the molecular weight distribution and glass transition temperatures. Values of n were found to vary from 0.5 to 30 for the homopolymerization of MMA. However, the presence of VAc in the copolymerizing system drastically reduces n . This can lead to a dramatic increase in the average molecular weight of the copolymer since it alters the ratio of propagation to termination in the polymerizing particles.