THERMAL EVALUATION OF CURING OF SBR BASED ADHESIVES USING DICUMYL PEROXIDE

Curing is an important process in adhesive formulation, but scant reports on the study of the kinetics of curing in adhesive are currently available, particularly for formulations including styrene-butadiene copolymers. The focus of the present work was to thermodynamically quantify the curing reaction in pressure-sensitive adhesives (PSA) obtained from styrene-butadiene copolymers, the effect of dicumyl peroxide (DCP) ratio, which acts as a crosslinking agent, and also evaluate the effect of two reactive adhesive resins, sylvalite and piccolyte. Kinetic parameters were determined by differential scanning calorimetry (DSC) in an isothermic and dynamic mode, gel content was determined as was swelling degree, given these characteristics can be associated with the curing reaction. The kinetic study showed the curing reaction was first order, according to the Ozawa and Kissinger equation. Resins have affinity to BR segment, while in the case of sylvalite and piccolyte to the PS segment, varying behavior with dicumyl peroxide in the adhesive mixture. Lower swelling values were associated with an increase in crosslinking, indicative a curing reaction took place, and the gel content test was used to corroborate the results