Effect of Catalyst Concentration of the Cured Properties of a Medical Grade RTV Silicone Elastomer

Results of an experimental investigation are presented in which mechanical properties, degree of swelling, structural uniformity (by electron microscopy), lipid uptake and implantation effects were studied on samples of silicone elastomers made with various catalyst concentrations and effects are presented. The data reported differ from previously reported results in so much as the cured polymer properties are not independent of the catalyst concentration. There are systematic deviations which are inherent in the preparation of the samples. The time required for the polymer to reach a gel state is a function of the catalyst concentration. Since the blending time is the same for all batches, approximately equal volumes of atmospheric gases are entrapped in the liquid catalyzed polymer. The time available for the bulk of the air to escape from the polymer before gel is variable depending upon the catalyst concentration. Therefore, the results reported reflect not only catalyst concentration and the primary treatment variables but also the composite effects of entrapped gases and moisture as a function of cure time.