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In recent years, due to the smoke suppression of the material, the increasingly stringent requirements of low toxicity, many of the traditional flame retardants facing difficulties, and halogen-free phosphorus-containing flame retardants by low smoke, low toxicity to their development good opportunity. Polypropylene (PP) as a general-purpose plastics, good chemical stability and electrical insulation, the oxygen index of only 17-19%, is a flammable material. Therefore, the development of new halogen-free phosphorus-based flame retardants and improve the flame retardant properties of polypropylene, polypropylene flame retardant research focus in today's world has become. In this paper, neopentyl glycol and phosphorus oxychloride as the basic raw synthesis of 2 - chloro-2 - oxo -5,5 - dimethyl-1 ,3,2 - phospho dioxane (DOPC), and then with The pentaerythritol first synthesis of new halogen-free phosphorus-based flame retardants (5,5 - dimethyl-1 ,3 - dioxino within phosphoryloxymethyl) pentane (DOPNP). Using infrared spectroscopy (FTIR), the 1HNMR, 31P NMR, TGA, and other methods of its structure characterization, and thermal stability. TGA results show that with good charring DOPNP initial decomposition temperature of 236.4 ° C (mass loss of 1%), 600 ° C when carbon residual amount of 41.2%, 800 ° C when carbon residual amount of 22.9%. DOPNP ammonium polyphosphate (APP), melamine polyphosphate (MPP) and synergist 4A molecular sieve (Zeolite 4A) complex, a new intumescent flame retardant (IFR) for polypropylene flame retardant. Flame retardant compound through a series of trials, drawn DOPNP / APP / MPP complex ratio of 1/10/5. Add to this the best ratio of intumescent flame retardant (IFR) polypropylene (PP), to explore the intumescent system by PP flame retardant properties. Flame retardant test The experiment shows DOPNP as a carbon source can effectively improve the level of IFR-PP oxygen index and UL-94. When IFR content is 30wt%, IFR-PP oxygen index of 31.3%, UL-94 V0 level. TGA, Cone, SEM and other means of study and characterization of the thermal degradation behavior of IFR-PP composites, combustion behavior and morphology of carbon residue. TGA results show that DOPNP-APP-MPP has a good char formation forming ability. Its initial decomposition temperature of 216 ° C (mass loss of 1%), 600 ° C when carbon residual amount of 55.1%, 800 ° C when the a carbon residual amount to 47.5%; Cone test results show that the PP DOPNP-APP-MPP Add can effectively reduce the the PP heat release rate (HRR), total heat release (THR), smoke generation rate (SPR), the total amount of smoke generated (TSP) and CO formation rate (COP); mechanical properties and SEM tests show that, DOPNP can effectively promote the dispersion of IFR in PP and get so much more compact and stable carbon layer.
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