synopsisThe torsional braid technique for studying the polymerization of viscous substances has been extended to a study of the homogenous catalytic behavior of a number of acidic and basic catalysts in the polymerization of carboxy-terminated polybutadiene with tris(methy1 aziridiny1)phasphine oxide. No general cat,alytic behavior was observed. Specific catalysis was observed in the case of lithium oleate, where the gel time was decreased, and in the case of bis(tri-wbutyltin) oxide, where the gel time was increased. The average energy of activation for all of these polymerizations was 13.9 f 0.5 kcal./mole. This energy of activation and the reaction environment, when compared with the data in the literature, strongly suggest that the explanation that a change in the rate-determining step occurs as a function of the polarity of the reaction medium fails to account for all of the results.

SynopsisThe torsional braid experiment of Lewis and Gillham has been so modified that kinetic parameters can be obtained in polymerizations conducted with viscous prepolymers. The relative rigidity curve is interpreted in terms of extent of cure. The activation energy for the polymerization of a carboxyl-terminated polybutadiene with an aziridinyl compound has been measured.