Development of polycarbonate with 5vb flame retardacy

Abstract

The flame retardancy of bisphenol A polycarbonates (PC) containing one to four flame retardants (FRs) was determined by limiting oxygen index (LOI) measurement and UL 94 5VB rating test. Two of the formulations were complied with UL94 5VB rating at 2.0 mm thick with 20% higher LOI value than the neat PC. Interestingly, the first formulation containing 15% by weight of tetrabromo bisphenol-A (TBBA) can be reduced to 10% by adding 5% of bisphenol-A bis(diphenyl phosphate) (BDP) to form the second formulation. The improvement in flame retardancy of PC compositions arose from synergistic interaction of these additives. These two formulations were characterized by TGA, FTIR, Raman spectroscopy, SEM and mechanical properties. The high content of FRs of the selected samples reduced the mechanical property especially the impact strength significantly. Surprisingly, this can be improved by adding of the impact modifier while maintaining the flame retardancy of PC.