The Preparation Of Poly Phosphate Flame Retardant And Its Application On The Epoxy Resin

The halogen flame retardants are restricted because it can produce hydrogen gas,which have impact on the environment and human.Studies have shown that polyphosphate ester flame retardant is a good substitute for halogen flame retardant.Epoxy resin（EP）is widely used in many areas because of its good adhesion.However,the flammability of EP is also limited in many areas.Therefore,flame retardant modification of EP is one of the hot spots in current research.In this paper,three flame retardants were synthesized by a simple and efficient method,then added to EP for flame retardant modification.The research content and results are as follows:（1）P-methyl phenyl dichloride phosphate（PPTP）and p-ethyl phenyl dichloride phosphate（PPEP）were synthesized from POCl₃,p-methyl phenol and p-ethyl phenol.Then,PPTP and PPEP were polymerized with 10-（2,5-dihydroxyphenyl）-10-hydro-9-heterophene-10-oxides（ODOPB）,respectively.At the same time,PPTP was polymerized with 4,4-dihydroxy biphenyl to obtain the polymer（PBDTP）.The flame retardant was characterized by FTIR and NMR,and its thermal properties were analyzed by TG.The results showed that the thermal degradation process of PODOTP and PODOEP were one step,PBDTP was done in two steps,The R_700℃of three kinds of flame retardants were 31.7%,19.66%and 48.79%,respectively.（2）PODOTP,PODOEP,PODOTP/APP and PODOEP/APP were respectively added to EP.The modified EP was analyzed by LOI,UL-94 and CONE.Studies have shown that both PODOTP and PODOEP can improve the LOI and UL-94 of EP,and can make the material have lower HRR,THR and COP,but PODOEP has better performance.The compound flame retardant has the same change effect,and PODOEP/APP has better flame retardant effect.（3）PODOTP/MMT and PODOTP/APP/MMT were added to EP respectively to analyze the related properties of modified EP.The research results showed that both of the two compound flame retardants could effectively improve the flame retardant properties of the material while reducing the amount of flame retardant additive,and PODOTP/APP/MMT had better performance.（4）PBDTP and PBDTP/APP were added to EP respectively.Adding PBDTP alone could improve the LOI of EP,but the UL-94test was not obvious.The UL-94 of modified EP could only reach V-1 level when W_PBDTP=15%.The LOI of modified EP was increased to 24.6%,and the UL-94 reached V-0 level when W_PBDTP/APP=15%.TG results showed that PBDTP and PBDTP/APP could increase R_700℃and enhance the thermal stability of EP.CONE results showed that PBDTP elevated pK-HRR of the EP,and PBDTP/APP could significantly improve the flame retardancy and smoke suppression of the material.