Multi-component coupling synergistic effect of resourced gold tailings on intumescent flame-retardant polypropylene

Addressing the challenge of resource utilization of gold tailings. A high performance flame-retardant fillers (K-GTF) were prepared from gold tailings (GTF) by coupling and condensation for application to intumescent flame-retardant polypropylene (PP). K-GTF enhances the flame-retardant, thermal stability, smoke suppression and mechanical properties of flame-retardant PP through synergistic approach. The results show that K-GTF demonstrates good flame-retardant synergism, with PP composites containing 3% additive (PP/G3) exhibiting substantial flame-retardant and smoke suppression characteristics. Notably, PP/G3 boasts a limiting oxygen index (LOI) of 36.1%, which is substantially higher than the 33.6% LOI of the flame-retardant PP without added K-GTF (PP/G0). Furthermore, the peak heat release rate (PHRR), peak smoke production rate (PSPR), total heat release rate (THR), and total smoke production (TSP) of PP/G3 were decreased by 32.5%, 26.9%, 31.6%, and 21.5%, respectively, as compared to PP/G0. According to the synergistic mechanism analysis, K-GTF exerts a multi-component coupling synergistic effect, which promotes the production of phosphorus-rich cross-linking structures in flame-retardant PP materials during the combustion, thereby promotes the formation of stable, dense and intumescent char to further enhances the flame-retardant performance of the PP materials. In terms of mechanical effects, the introduction of K-GTF alleviates the issue of a substantial decline in mechanical properties typically caused by flame retardants in PP materials. This indicates that K-GTF improves the compatibility between the flame retardants and the PP matrix, thereby enhancing the mechanical properties of the flame-retardant PP materials.

Highlights

• Successfully synthesis a flame-retardant synergist (K-GTF).
• K-GTF has good synergistic flame-retardant effect.
• K-GTF substantially enhances char formation and thermal stability of flame-retardant PP.
• K-GTF exerts a multi-component coupling synergistic effect.
• K-GTF enhances the compatibility between the PP matrix and the flame retardants.