Phosphorus-nitrogen-silicon-containing polymeric flame retardant and preparation method and application thereof
Disclosed are a preparation method of a phosphorus-nitrogen-silicon-containing polymeric flame retardant and application thereof. The chemical structure of the polymeric flame retardant is wherein m=10˜100, n=10˜100. The synergistic flame-retardant effect between the phosphorus, nitrogen, and silicon in the phosphorus-nitrogen-silicon-containing polymeric flame retardant increases the flame retardancy of epoxy resin.
1. A preparation method of a phosphorus-nitrogen-silicon-containing polymeric flame retardant, wherein: the synthetic route is as follows:
where m=10˜100, n=10˜100;
the detailed steps are described as follows:
(1) glycidol, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), triethylamine and a first organic solvent are added to the reaction vessel in turn under ice bath, the reaction is carried out at room temperature for 4˜16 hours, then it is repeatedly extracted and washed with water, the organic phase is dried with anhydrous magnesium sulfate and vacuum filtered, finally the phosphorus-containing epoxy monomer EP-DOPO is obtained after the solvent is removed by rotary evaporation, the molar ratio of the glycidol, DOPO and triethylamine is 1:0.5˜2.5:0.5˜2.5;
(2) the phosphorus-containing epoxy monomer EP-DOPO obtained in step (1), aminopropyl polyhedral oligomeric silsesquioxane (POSS—NH 2 ), sodium methanol and a second organic solvent are added to another reaction vessel in turn, heated to 60˜120° C. under protection of nitrogen, and reacted for 4˜24 hours, then the filter cake is obtained by methanol precipitation, the filter cake is washed with methanol, and the white solid obtained is dried in the vacuum drying box at 60° C. for 24 hours, thus the phosphorus-nitrogen-silicon-containing polymeric flame retardant is obtained, the molar ratios of the EP-DOPO, aminopropyl polyhedral oligomeric silsesquioxane and sodium methanol are 1:0.01˜0.1:0.01˜0.1.
2. The preparation method according to claim 1 , wherein the first organic solvent is dichloromethane, toluene or carbon tetrachloride.
3. The preparation method according to claim 1 , wherein the second organic solvent is toluene, N, N-dimethylformamide or 1,4-dioxane.
4. A flame retardant epoxy resin comprising the phosphorus-nitrogen-silicon-containing polymeric flame retardant prepared according to the method of claim 1 .
5. The epoxy resin according to claim 4 , wherein: an epoxy resin prepolymer is taken and heated to 70˜110° C. and 0.1˜50 wt % phosphorus-nitrogen-silicon-containing polymeric flame retardant is added, and stirred until the mixture is uniformly transparent, a curing agent 4,4′-diaminodiphenylmethane (DDM) is added according to stoichiometric ratio until it is completely dissolved, poured into an aluminium mold, then a curing procedure was set to cure the mixture and the flame retardant epoxy resin was obtained.
6. The epoxy resin according to claim 5 , wherein: the epoxy resin prepolymer is bisphenol A epoxy resin.
7. The epoxy resin according to claim 5 , wherein: the mass ratio of the epoxy resin prepolymer to the curing agent 4,4′-diaminodiphenylmethane is 8:2.02.
8. The epoxy resin according to claim 5 , wherein: the curing procedure is: 120° C. for 4 h, 140° C. for 2 h and 180° C. for 2 h.