The Synthesis And Flame Retardancy Of Thermal Plastic Polyurethane

Thermoplastic polyurethanes?TPU?are very widely used materials in production and daily life,but it's easy to burn and generates a lot of smoke and toxic gases,so it's necessary to improve TPU's flame retardancy and thermal stability.Generally,there are two kinds of flame retardant we often use—addictvie type and reactive type,the former has obvious effect but poor compatibility with TPU,can easily deposit,besides,large amount of addition does big harm to the mechanical properties of TPU.While,reactive flame retardant could endow permanent flame retardancy to TPU and keep well mechanical properties at the same time.In this paper,three reactive flame retardants and two kinds of addictive flame retardant in low addition were studied about their effect to TPU properties.First of all,based on MDI:PTMG:BDO=2:1:1,homemade 4-?phenylethynyl?di?ethylene glycol?phthalate?PEPE?was incorporated in the structure of TPU by means of replacing BDO partly.Through FTIR?GPC?mechanical tensile test?DSC?TG?CONE as well as LOI etc.The result showed that PEPE can obviously improve the mechanical property of TPU.Tensile strength increased from 10.32MPa to 39.21MPa,elongation at break increased from 1383.8%to 1600.2%and the amount of residual carbon increased from0.27%to 6.74%.peak Heat Release Rate?p-HRR?and Total Heat Release?THR?decreased by 58.80%and 61.76%respectly,mean CO and CO₂ yield also reduced,LOI increased.Two anhydride——PTDA and BPTDA were incorporated in TPU by replacing BDO partly,their influence on TPU properties were studied.PTDA and BPTDA both improved the tensile strength and elongation at break of TPU,and also it's thermal stability,but BPTDA was less efficient than PTDA.The LOIs of two compounds respectly increase from 19.8 to23.8 and 22.7.P-HRR and THR respectly decreased by 44.13%and 45.54%at 40%PTDA.Further research was centre on its replacing all BDO to synthesis different content of hard segment TPU.As the content of hard segment increased,the elongation at break decreased,tensile strength increased and then reduced.The initial degradation temperature and amount of residual carbon of TPIU2:1:1 respectly increased by 37.4??16.39%.P-HRR and THR reached minimum,respectly decreased by 51.35%and 53.38%.LOI changed from 19.8 to 24.6.Compared to almost none-carbon-layer original TPU,TPIU2:1:1 could form complete carbon layer,and was accompanied by expansive phenomena during combustion.And then,two addictive flame retardant POSS—octaphenyl silsesquioxane?OPS?and polyphenylsilsesquioxane?PPSQ?were studied about their effect on TPU at low addition.These two substances can improve TPU's mechanical properties efficiently,residual carbon also increased.When the content of OPS and PPSQ respectly was 3%and 5%,the p-HRR of TPU was lowest from 1928.1kW/m² to 690.9 kW/m² and809.4 kW/m²,decreased by 64.2%and 58.02%,THR also decreased from 169.9 MJ/m² to 60.2 MJ/m² and 90.5mJ/m²,reduced by 64.6%and 46.73%.At the same time,mean CO₂ and CO yield decreased apparently.The addition of OPS and PPSQ made the LOI of TPU increase to some degrees.