Preparation Of Cattail Active Carbon Loaded Iron Oxide And Its Flame Retardant Application In PVC And EP

Polymer materials have a wide range of applications due to their diverse types,various preparation processes,and wide application range.However,polymer materials generally contain flammable elements such as N,Cl,and S,and organic processing aids.Polymer materials can easily cause serious fires in daily life.Therefore,the flame retardant research on polymer materials has attracted the attention of scholars.In this paper,the higher specific surface area activated carbon?AC?and the iron oxide-loaded activated carbon?AC-Fe₂O₃?were prepared using velvet as raw material,and the obtained samples was added into soft polyvinyl chloride?PVC?for investigation of flame retardancy and smoke suppression performance.In addition,AC-Fe₂O₃ and ammonium polyphosphate?APP?were incorporated into epoxy resin?EP?for investigation of the flame retardant and mechanical properties.The specific research content is as follows:In the first part,AC was prepared via a nitrogen activated-carbonization of cattail and phosphoric acid as an activator;the synthesis of AC-Fe₂O₃ via impregnating roasting method of AC as carbon-base and iron oxalate as impregnating solute.The samples were characterized by SEM,IR,XRD,TG-DTG and chemical titration.The results showed that the specific surface area with 532.46 m²·g^-1,the pore volume was 0.41 cm³·g^-1,and the average pore size was 3.09 nm of AC,respectively.It was a relatively high specific surface area activated carbon with micropores;moreover,the Fe₂O₃ dispersed homogeneously on the surface of AC,and thermal stability remarkably improved.In the second part,the AC and AC-Fe₂O₃ of 5wt%were added into soft PVC for investigation of flame retardancy and smoke suppression performance.The results indicated that AC and AC-Fe₂O₃ improved residual char of PVC and affect the decomposition process of PVC.AC as a physical barrier in the early thermal decomposition,and AC-Fe₂O₃improved the residual char for PVC.Moreover,AC-Fe₂O₃ exhibited good suppression performance than AC,which can significantly reduce the amount of smoke released.In the third part,the synergistic effect between AC-Fe₂O₃ and APP for flame retardancy and smoke suppression performance of EP was studied.The results showed that the LOI of the EP composites increased from 25.3%to 28.0%of 1 wt%of AC-Fe₂O₃ and 3 wt%of APP,and satisfied flame retardant grade?V-0?without any droplet dripping.The dense and stable of residual char for EP significantly improved during the combustion,the internal collapse and voids greatly reduced,and the residual char significantly increased.The improved flame retardancy and smoke suppression performance of EP are attributed to synergistic effect of APP plus AC-Fe₂O_3.On the one hand,the APP catalytic early stages of degradation of EP,and produces a carbon layer that has good thermal stability,which acts as a heat insulator and an oxygen barrier.Moreover,AC can prevent the degradation products from volatilizing and escaping by the physical barrier function;the presence of Fe element also promotes the decomposition of APP,and reacts with the decomposition products of APP to generate heat-resistant pyrophosphate in the later stage of the reaction,thereby the thermal stability of the EP composites significantly improved.