Study On Anti-dripping And Halogen-free Flame Retardant TPO Composites

In this paper,according to the anti-dripping flame retardant mechanism,anti-dripping flame retardant composite systems were designed with thermoplastic polyolefin elastomers(TPO)served as matrix.The research of TPO flame retardant materials in the world and anti-dripping flame theory were summarized.The magnesium hydroxide(MH)surface modification,the flame retardant properties,anti-dripping properties and stress-strain behavior of TPO composite systems were studied,which MH as main flame retardant,aluminum hydroxide(ATH),silicone rubber as asynergistic flame retardant.The thermal degradation behavior of composite systems were studied by TGA.The analysis of infrared spectroscopy(FT-IR),viscosity test and the degree of crosslinking test for anti-dripping and flame retardant theory.At the same time,the dispersion of flame retardants in matrix were analyzed by scanning electron microscopy(SEM).The results were obtained as followed:The best surface activation of MH was vinyl silane coupling agent,activate index of MH was large,the plastisizer absorption of MH was low,and the surface tension of MH modified by vinyl silane coupling agent was similar to TPO.The smaller of the particle size of MH,and the larger of the amount of MH were,the larger of the oxygen index were.When the particle size of MH was 5000 mesh,the amount of MH was 100 phr,the LOI of the composite system reached 28.4%.when the composite system was processed by the masterbatch method,the LOI of the composite system reached up to 29.2%.The viscosity of the composite systems were increased by added MH,melt dripping phenomenon did not appear.When MH was at certain amount,the smaller of particle size of MH,the larger tensile strength and elongation at break were.when the composite system was processed by the masterbatch method,the largest elongation at break were up to 373.00%.In the TPO/MH anti-dripping and flame resistant composite systems with ATH as synergistic flame retardant,ATH added enable to improve flame retardancy and mechanical properties of the composite systems.when MH/ATH=50/50,the LOI of composite system reached 32.4%,and the dripping phenomenon didn't appear,the elongation at break of the composite systems was up to 380.46%.TGA analysis showed that ATH added reduced thermal degradation rate of composite systems.TPO composite systems were made with MH,silicon rubber as synergistic flame retardants,the amount of silicone rubber and the amount of vulcanizing agent were discussed have an effect on flame retardant properties,anti-dripping properties and the stress-strain behavior of the composite systems.When MH/silicone rubber=80/20,the LOI of the composite system reached 31.6%,melting and dripping phenomenon did not appear,tensile properties of composite systems were improved,elongation at break of reached up to 343.43%.When the amount of vulcanizing agent was 0.6%of silicon rubber,The LOI of the composite systems reached up to 33.4%,the elongation at break was up to 391.32%.TGA analysis showed that silicone rubber added changed char layer structure of composite systems,Si-C structure help composite systems formated more compact char layer.