DETERMINATION OF THE OPTIMAL CURE TIME FOR SULFUR VULCANIZED SBR RUBBER USING BLOW ANALYSIS TECHNIQUE

ABSTRACT We introduce an innovative approach for predicting optimal vulcanization times in SBR-based rubber products to eliminate internal defects like blow holes and achieve a uniform structure. Unlike conventional rheological methods, which may overlook factors like product shape and thermal conductivity, our method visualizes the vulcanization process within a wedge-shaped sample to identify the equivalent vulcanization time [ t eq at blow point (BP)] required to prevent defects. Findings show that higher accelerator-to-sulfur (A/S) ratios and total content (A+S) accelerate vulcanization and reduce blow-related issues, with unique behavior in semiefficient vulcanization (s-EV, A/S ratio ∼ 1.1). The t eq at BP emerges as a key indicator of vulcanization uniformity, potentially enhancing quality control beyond rheometer data alone. Blow occurrence tendency appears to be material-dependent, indicating further study is needed to refine rubber formulations and vulcanization strategies. This approach complements traditional methods, offering enhanced precision in optimizing vulcanization for complex rubber products.