TG-FTIR and TG-MS analysis applied to study the flame retardancy of PVC–castor oil-based chlorinated phosphate ester blends

We report here for the first time a chlorinated phosphate ester derived from castor oil (CPCO) for preparing flame-retardant poly(vinyl chloride) (PVC) materials. Flame-retardant PVC materials plasticized with different amount of CPCO were prepared by solvent casting method. The property of flame-retardant PVC materials was investigated with LOI, SEM, TG, TG-FTIR and TG-MS. The results showed that the LOI value of plasticized PVC blends reached 36.3 %. TG-FTIR and TG-MS were used to investigate the pyrolysis products during the thermal degradation process. The nonflammable gases included a few phosphorus-containing compounds, such as P–O–C and P–OH, indicating that more phosphorus-containing compounds were generated during the thermal degradation of CPCO still retained in char residue rather than gas phase, which promoted the formation of high-quality carbon residue. Consolidated and compact structure of carbon residue was produced and covered on the surface of flame-retardant PVC materials, which was effective to prevent the heat flux and air entering PVC matrix, then protected the underlying materials and improved the thermal and flame-retardant performance of PVC materials.