Abstract:

To improve the safety of EP in application fields, Calcium Terephthalate(CaT), a metal-organic framework (MOF) material, was utilized synergistically with the liquid flame retardant bisphenol A bis (diphenyl phosphate) (BDP) to flame-retardant modify the EP/PPO system. The flame retardant properties were characterized using the limiting oxygen index, vertical burning test, and cone calorimeter tests. The curing kinetics and pyrolysis kinetics of the modified EP/PPO system were investigated using the Kissinger, FWO (Flynn-Wall-Ozawa), and Crane equations. The results show that when 8% BDP and 2% CaT are added to EP, the composite exhibits good flame retardant performance. 34.5% of the limiting oxygen index is reached. V-0 rating of the vertical burning test is achieved. The peak heat release rate and the total heat release are reduced by 76.6% and 51.5% respectively compared to pure EP. The incorporation of CaT is found to be beneficial for the curing reaction. The optimal curing temperature could be determined by extrapolation from non-isothermal differential scanning calorimetry curves. It is an initial stage at 100 ℃, followed by 120 ℃, and finally 170 ℃. Analysis of non-isothermal thermogravimetric analysis curves and pyrolysis kinetics demonstrates that EP/PPO system exhibits lower activation energy.

Key words: flame retardant, epoxy resin (EP), low-molecular-weight polyphenylene oxide (PPO), curing kinetics, pyrolysis kinetics