Construction And Flame Retardant Mechanism Of TPU Composites Based On Oyster Shell Powder

With the development of aquaculture,more and more solid wastes are produced around the world.As one kind of solid wastes,oyster shell wastes have brought many ecological security problems.As an active research direction,the application of oysters shell wastes have attracted many scientists`attention.Constructing a synergistic flame-retarded TPU system by the combination of OSP/APP,OSP/Chitosan-P.Constructing a flame-retarded TPU system by OSP modified by MP,AHP.The flame retardant properties of TPU composites were investigated,and fire hazards were discussed.The work of my dissertation is composed of the following parts:?Fire hazards of TPU compounded with different content of OSP that were studied by many tests.The data from CCT showed that the peak heat release?pHRR?and total heat release?THR?of OSP-4 with 10.0 wt%OSP decreased by 70%and37.5%compared with pure TPU,respectively.The smoke concentration of burning sample could be reduced,as OSP were incorporated in TPU system.The peak smoke production rate?SPR?of OSP-4 decreases by 69.8%compares with pure TPU.In summary,OSP could lower the fire hazards of TPU materials.?By constructing the OSP/APP flame-retarded TPU system,the combustion performance of TPU composites were studied.The results showed that there was a good synergistic effect of reducing the heat and smoke release when OSP was used with APP in TPU.The cone calorimeter?CCT?results showed that the pHRR value of OSP2/APP8?2 wt%OSP and 8 wt%APP?decreased by 57%than that of APP10?10wt%APP?.The results from smoke density test?SDT?showed that the luminous flux?LF?of OSP2/APP8 was 29.2%which decreased by 6.75%than that of APP10.Thermogravimetric infrared?TG-IR?results further confirmed that OSP2/APP8reduced the fire hazard of polymers by releasing more inert gases and lower organic compounds.?The flame retardancy system of TPU was constructed by OSP which combined with Chitosan-P.The combustion performance of TPU composites were analyzed.The combination of OSP/Chitosan-P could effectively reduce the heat releasing and smoke generation of TPU composites.The CCT results showed that total heat release?THR?value of CN-P was 62 MJ/m² which reduced by 11%than that of CN composite.The SDT results showed that the LF of CN-P sample was 30%which was higher than that of CN composites.Therefore,the fire hazards of TPU composites were effectively decreased by introducing OSP/Chitosan-P.?Synthesis of flame retardant MP-OSP by in situ precipitation method with melamine phosphate were precipitated on the surface of OSP.The combustion behavior of TPU/MP-OSP composites were investigated.The CCT results revealed that the fire hazards of TPU composites filled with MP-OSP could be reduced.The pHRR of MOS containing 10.0 wt%MP-OSP decreased to 170.9 kW/m² from 1772.4kW/m² compared with pure TPU.TG-IR also confirmed that the inert gasses?including CO₂,ammonia,and water vapor?and organic compounds produced by MOS have played reinforcing role in TPU composites.?Synthesis of flame retardant AHP-OSP by in situ precipitation method with aluminium hypophosphite?AHP?were precipitated on the surface of OSP.The combustion behavior of TPU/AHP-OSP composites were investigated.The CCT results showed that the peak heat release rate?pHRR?of AS2?51W/g?decreased 23.4%compared with pure TPU?128 W/g?.The SDT results showed that the LF value of AS2 was 17.3%which was higher than that of CN composite.And also TG-IR confirmed that AHP-OSP could promote the decomposition of TPU materials to produce more inert gases and lower harmful gases.