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The viscosity effect on autoacceleration of the rate of free radical polymerization
Author(s) -
Dvornić Petar R.,
Jaćović Mihailo S.
Publication year - 1981
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760211209
Subject(s) - polymerization , viscosity , materials science , suspension polymerization , radical polymerization , polymer chemistry , methyl methacrylate , polymer , suspension (topology) , thermodynamics , composite material , physics , mathematics , homotopy , pure mathematics
The reaction kinetics at 70°C were investigated for the suspension polymerization of methyl methacrylate initiated by benzoyl peroxide in the presence of variable amounts of dodecyl mercaptan. A dilatometric method designed to follow a suspension polymerization was used. It showed that the autoacceleration of the rate of polymerization begins at higher conversions and becomes less pronounced as the concentration of chain transfer agent is increased. The investigations focused on the determination of the viscosities of the reaction mixtures at the onset of autoacceleration. It was concluded from the flow curves obtained for different reaction mixtures that there exists a critical solution viscosity at which the autoacceleration begins, which supports the accepted theory about the nature of this phenomenon. Measured at a shear rate of 10,000 s −1 and at 25°C this viscosity was found to equal 0.6 poise regardless of the molecular weight of the growing polymer.