Optimization of BaSO۴ Filler Content in Novolac Epoxy Coatings for Enhanced Thermal Resistance and Adhesive Performance

This study presents the development of a thermally resistant Novolac epoxy coating system reinforced with barium sulfate (BaSO۴) as a flame-retardant filler. Coatings with BaSO۴ contents ranging from ۰ to ۶۰ wt% were fabricated to evaluate the influence of filler loading on flame resistance and adhesion. Flame tests showed that increasing BaSO۴ significantly reduced the burn radius, indicating enhanced thermal protection due to the insulating effect of BaSO۴ and the formation of a stable cross-linked resin network. The best flame resistance was observed at ۴۰ wt% filler, achieving a ۵۰.۳۴% reduction in burn radius compared to the unfilled resin. However, further increasing the filler content weakened adhesion to the metal substrate, with detachment observed at ≥۵۰ wt%, likely due to reduced resin and poor wetting. Overall, filler concentrations between ۳۰-۴۰ wt% provided an optimal balance between thermal resistance and mechanical integrity, making the coating suitable for use in high-temperature and protective applications.

کلیدواژه ها:

Coating ، Epoxy Novolac resin ، Barium sulfate ، Flame retardancy ، Pull-off adhesion