The effect of OCoAl-LDH and OCoFe-LDH on the combustion behaviors of polyvinyl chloride

The effects of the modified layered double hydroxide (LDH) of Co/Al (OCoAl-LDH) and the modified LDH of Co/Fe (OCoFe-LDH) on the combustion behaviors of polyvinyl chloride (PVC) during pyrolysis processes were compared and investigated. The thermal degradation and combustion behavior of the PVC composites were investigated by thermogravimetric analysis (TGA), microscale combustion calorimetry (MCC), and cone calorimetry (CONE). The results indicate that the incorporation of LDHs brought about the improved thermal stability and reduced heat release of PVC composites at a high temperature. The smoke-suppression properties of the composites are investigated by steady-state tube furnace (SSTF), and the results indicated that the toxic gases such as CH4, CO, and NxO were inhibited by both of the two LDHs, but the OCoFe-LDH has a better effect on the smoke suppression. Subsequently, the char layer was investigated by scanning electron microscopy-energy-dispersive spectrometry (SEM-EDS) and Raman analysis. The results indicate that the LDHs can promote the dechlorination of PVC during the thermal oxidation process and can inhibit the production of HCl in inert gas. Generally, OCoAl-LDH and OCoFe-LDH can be potential catalysts for waste disposal and can improve the fire safety of PVC.