Synthesis Of Organophosphorus Hybrid Flame Retardants And Its Application In Epoxy Resins

Epoxy resin(EP)has excellent chemical resistance,perfect mechanical properties,adhesive properties and electrical insulation,and good dimensional stability,so it is widely used in the fields of aerospace,sporting goods,defense technology,and electronic appliances.The use of epoxy resins is greatly limited in many highly flame-retardant areas due to the fact that epoxy resins are flammable materials like most polymer resins.Thus,it is especially important to improve the flame-retardant performance of the epoxy resin.For this purpose,three organophosphorus hybrid flame retardants were synthesized in this thesis and applied to epoxy resins to study its flame-retardant property and mechanical property,the specific research is as follows:1.A novel halogen-free flame retardant HPNZ was prepared via four metal salts,phosphonitrilic chloride trimer(HCCP)and 2,7-dihydroxynaphthalene(DDPA).Research results proved that when 2.0 wt%of HPNZ was added in the EP system the impact strength and tensile strength increased by 10.7%and 20.8%,respectively.When the addition amount of HPNZ was 4.0 wt%,the limiting oxygen index(LOI)value reached 29.1%,and the burning time of vertical combustion(UL-94)was shortened from 195.0 s to 42.1 s.Meanwhile,the Cone calorimetry test(CCT)result showed that the total heat release(THR)value was reduced from 95 MJ/m2 to 67 MJ/m2,and the total smoke production(TSP)value was decreased from 33 m2 to 20 m2.2.The new flame retardants CDMS and CPDMS were prepared by tetraethyl orthosilicate(TEOS),copper acetate,dopamine hydrochloride(PDA),dicyandiamide(DCD)and phytic acid(PA).The experiment results showed that the flame-retardant effect of EP was improved significantly with the increased of the addition of CDMS and CPDMS.When the addition of CDMS and CPDMS flame retardants in epoxy resin reached 3.0 wt%,the effect of flame retardants on mechanical property of EP was the least.The CCT and LOI test results showed that THR decreased to 7.3%,the TSP was reduced to 9.1%,and the LOI value of EP/CDMS-3 was 29.6%.the LOI value of EP/CPDMS-3 was 28.2%,and the THR decreased from 82 MJ/m2 to 67 MJ/m2,TSP decreased from 55 m2 to 38 m2,THR and TSP value were reduced by 18.3%and 30.9%,respectively compared to pure EP.3.The novel frame retardant non-halogenated phosphorus-containing flame retardant APOP was synthesized by the Schiff base reaction using 1,4-dialdehyde benzene(PHDE),9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO),polyhedral oligomeric silsesquioxane(POSS),aniline and p-aminoacetophenone as raw materials.The experiment showed that impact strength,tensile strength and flexural strength increased by 78.6%,66.0%and 32.3%,respectively when the addition of APOP was 3.0 wt%in EP.Meanwhile,the LOI value reached 30.1%and 31.0%when 3.0 wt%and 5.0 wt%of APOP flame retardants were introduced into EP,and the UL-94 test passed V-1 and V-0.