Studies On The Synthesis, Structure And Flame Resistance Of Phosphorus And Nitrogen Containing Compounds

Nowadays, the polymers are used extensively in every aspect of people's living and production, for example, the building, transportation, the electronic appliances and commodity. Because the polymers are flammable and easy to bring the destructive burning, which has caused the flame retardant polymeric materials to be asked increasingly. Many nations established a series of the relevant statute and policy. These factors promote the study and application of the flame retardant straight.In the new century, the people pay more attention to the problem of the environment. We hope that these additives not only make the material have good flame retardant , but also are lower toxicity to the person and environment. Nitrogen-phosphorus compounds as a kind of low smoke and low poisonous addition agent have been showing good anti-flaming and application foreground. With the development of the students'effort, new type flame retardants emerged in endlessly.According to the literature, the flame retardant products in our country have some fateful defects, for instance, lower molecular weight, liquid state, being apt to move and volatilize, worse heat-stability and the worsening physical function of the material. In order to improve these characters, we designed and synthesized three series compounds which structural symmetry , higher molecular weight and better heat-stability:( I ) 2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]-undecane-3,9-disubstitution ben zoylhydrazone(II) N-(5,5-dimethyl-4-substituted phenyl-2-oxo-l,3,2-dioxaphosphoyl)-substit uted benzoylhydrazone(III) N,N-di(5,5-dimethyl-4-substituted phenyl-2-oxo-l,3,2-dioxaphosphoyl)-4, 4 -diphenylmethane.The structures of the target compounds are confirmed by IR, ~1HNMR, MS and elementary analysis. The spectroscopy properties are analyzed systematically. The results show that the structures of the synthesized compounds are identical with the expected ones. Get one single crystal and it was characterized by X- ray diffraction, the results prove that the structures are accord to the compounds.TG and DSC analysis of some typical compounds are discussed to estimate theirstabilities. The results indicate that most of the compounds begin to decompose at 200"C and have certain thermal stability. They decompose rapidly during 220~400°C, and the temperature range overlap with th^ decomposition temperature range of most polymers, and it show good antiflaming compatibility with polymers. The high carbon residues at 600"C show that the compounds have good carbonization function.We applied the compounds to alkyd re$in varnish, epoxy resin (E-44) to test their flame resistance. The level combustion method (GB2408-80) used in epoxy resin are standard methods. The results indicate that the compounds have good flame resistance. Most compounds self-extinguish within Is or 2s with 1% addition in alkyd resin varnish. All compounds self-extinguish with 10% addition in epoxy resin(E-44), and the combustion length is about 10~25mm in the level combustion test. Compounds III have better flame retardant than compounds I and II in epoxy resin(E-44), it maybe caused by which melting point of compounds III is higher than others. The samples foam and expand during the combustion process without melting and dropping and with low smoking. We also gives a brief description of flame-retarding mechanisms and discussed the influence factor.The thermal analysis and initial fireproofing test show that the synthesized compounds have good flame retardant, and some compounds have application foreground.