High-pressure cure kinetics and unexpected cure separation of peroxide-cured silicone rubber under compressed CO2

Abstract

In this study, high-pressure differential scanning calorimetry (HP-DSC) was used to examine the curing process of a peroxide-cured silicone rubber (SR) system under compressed CO2 to investigate the influence of pressure and CO2 on the curing process. We found that the curing reaction occurred in two parts, described as cure separation, because of the dual effect of CO2 pressure and solvation at 6 MPa CO2. Consequently, peak fitting was used to calculate the kinetic parameters of the two-part reaction at 6 MPa CO2. Results indicate that pressure and CO2 exerted a combined effect on the curing reaction. In particular, pressure and CO2 solvation effects changed with varying conversion rates and CO2 pressures. This study provides an effective analysis methodology and an accurate kinetic model for characterizing and predicting high-pressure cure kinetics and unexpected cure separation in a peroxide-cured SR system under compressed CO2.