DEVOLATILIZATION WITH CHEMICAL-REACTION IN POLYMER-SOLUTIONS

It has been observed previously [1] that under the specific conditions prevailing in a reflux flask reactor, the overall rate of the transes terification reaction between an ethylene and vinyl acetate copolymer and 3-phenyl 1-propanol can be enhanced appreciably by the introductio n of boiling inert hydrocarbon solvents. In the present study, the sam e reaction carried out under a controlled removal of vapors in a stimu lator emulating a non-intermeshing counter-rotating devolatilization t win screw extruder, a significant acceleration of the reaction rate ha s also been observed. In agreement with the previous work [1], the int rinsic reaction mechanism and the chemical equilibrium do not appear t o be affected by boiling of the inert hydrocarbon solvents, nor does t he additional mechanical agitation due to the rapid bubble growth cont ribute to the increase of the overall reaction rate. Theoretical analy sis of the results confirms that the acceleration of the reaction rate originates from the localized mass transfer effect connected to the p resence of the bubble vapor-liquid interface films induced by devolati lization.