Synthesis of zinc porphyrin complex for improving mechanical, UV-resistance, thermal stability and fire safety properties of polystyrene

Polystyrene (PS) is one of the most commonly used general plastics. Nonetheless, PS is greatly limited by its inherent disadvantages such as high flammability, low stability and brittleness. To address these issues, 5,10,15,20-tetrakis(4-bromophenyl) porphyrin (TBPP) and zinc 5,10,15,20-tetrakis(4-bromophenyl) porphyrin (Zn-TBPP) were synthesized as multifunctional additives for fabricating high-performance PS composites. Both TBPP and Zn-TBPP showed high thermal stability and excellent UV-absorption, which significantly enhanced the UV-resistance of PS without sacrificing mechanical property after 100 h UV-aging. The addition of 5 wt% ZnTBPP led to the remarkable improvement of thermal stability of PS (41 ? and 79 ? increases in the thermal decomposition temperature at 5 wt% mass loss under N-2 and air, respectively). Moreover, contributed from the strong pi-pi interaction between porphyrins and PS chains, the mechanical properties of PS were enhanced when 5 wt% Zn-TBPP was added into PS (11.1% increase in tensile strength and 96.6% increase in elongation at break). Furthermore, compared to TBPP/PS, Zn-TBPP/PS exhibited an improved flame retardant performance with 26.0%, 14.4% and 31.5% reduction of peak heat release rate, peak CO and CO2 production respectively, indicating the catalytic flame retardant effect from zinc element.

Automated summary

In this study, TBPP and Zn-TBPP were synthesized as additives for PS composites, which significantly improved the thermal stability, flame retardancy, and UV resistance of PS while enhancing its mechanical properties.