Synthesis And Application Of Novel Intumescent Flame Retardents Containing Phosphorus

Recently, intumescent flame retardant (IFR) has received considerable attentions because of its unique flame retardant mechanism, high efficiency, low smog density and environment friendly. It could overcome the molten drops effectively in thermoplastic materials. Although IFR additives have been utilized in the flame retardation of flammable plastic and rubber, the researches on textile fabrics were hardly mentioned.The synthesis of novle intumescent retardants was one of the important parts in this article. Dichloro phosphorspirol (SPDPC) was synthesized from phosphorus oxychloride and pentaerythritol, then reacted with triethanolamine, trimethylolpropane and glycerol, and then generated the intumescent flame retardants IFR-11, IFR-12, IFR-13 with pentavalent phosphorus. The optimum synthesis technologies were obtained. The chemical structure of the products were determined by means of FTIR, ~1H NMR.The application of the new flame retardant on PET was researched in detail. The performance was compared within the three flame retardants. The conditions of treatment technology were optimized by single-actor experiment,and the optimum technology for IFR-11: the total concentration was 250 g/L, pH value was 4 around, curing 150 s at 180℃. After dealing with such a technology, smouldering time and flaming time of the PET fabric were both 0 s. The length of carbonization was less than 9 cm, and no dripping phenomenon, low frog. The LOI of polyester fabric rose from 22% to 26.3 %. The mixture performance was investigated. The results showed that there would be synergy effect if mixed with intumscent flame retardant while confront effect would be showed when mixtured with flame retardant that promoting dripping.The flame-retardant mechanism of IFR-11 for PET fabric was further investigated by thermogravimetric(TG), differential scanning calorimetry(DSC), FTIR, elemental analysis and Scanning electron microscope(SEM). The results showed that, IFR-11 had good char forming performance itself, and when was introduced into PET, it would promote the char forming of PET, delay the deep pyrolysis, enhance the thermal stability of PET and carbon residue. IFR-11 acted mainly in condensed phase and experienced intumescent flame retardant mechanism, the blowing agent turn the coating into a non-flammable cellular carbon foam layer which was at least ten times thicker.Other new flame retardants containing trivalent phosphous were prepared either. Dichlorophenylphosphine sulfide was greenly prepared from phosphorus trichloride, benzene and sulfur powder using ionic liquids method, then reacted with highly char forming polyols such as pentaerythritol and neopentyl glycol. The chemical structure and flame retardant mechanism of the products were determined by means of IR, ~1H NMR, TG, DSC and elemental analysis. The results showed that the products prepared from pentaerythritol have good char-forming and thermal stability. Compared with IFR-11, the char forming ability was lower, while the flame retardancy was not bad at all. The reason maybe that for compounds with trivalent phosphorus, part of phosphorus acted in the solid phase, the other parts acted in the gaseous phase, the small molecules could seize the free radicals in the gaseous phase, the fixed phosphorous compound could promote the char forming of PET and reduce the amount of flammable gas.