Flame Retarding Cyanate Eater Resin Based On Cerium Oxide Modified Boron Nitride

High thermal-resistant and flame retardant resin is a crucial material in the cutting-edge industry,and green flame retardant is the requirement for high temperature development today.This thesis aims to develop a new halogen-free and non-phosphorus flame retardant,and on this basis,developing a new heat-resistant thermosetting resin with high flame retardancy and high smoke suppression.The hexagonal boron nitride(h-BN)was modified by solid surface functionalization to obtain exfoliated boron nitride nanosheets(BN),and liquid phase non-covalent modification was used to get polydopamine(PDA)coated functional filler(BN@PDA).On this basis,BN@PDA/bisphenol A cyanate ester(BCy)(BN@PDA/BCy)composite was prepared.Then,the structure and properties of the BN@PDA and BN@PDA/BCy composite were studied,and the mechanism behind the improved flame retardancy and heat resistance of materials was discussed.Compared with BCy resin,the BN@PDA/BCy composite maintains good heat resistance.BN@PDA/BCy composite with 2wt%BN@PDA has delayed initial ignition time by 13 s,and the peak heat release rate(PHRR)and total heat release(THR)are reduced by 30.1%and 15.1%,respectively.The improved flame retardancy is attributed to the physical barrier effect of BN and the good interaction between BN@PDA and BCy resin.The ?-aminopropyltriethoxysilane modified cerium oxide(CeO2)reacted with BN@PDA,and the new functional filler(BN@CeO2)of CeO2 modified BN nanosheets was synthesized.Then,BN@CeO2 was embedded into BCy resin to fabricate new BN@CeO2/BCy composites with high thermal resistance.Compared with BCy resin,the BN@CeO2/BCy composite with 4 wt%BN@CeO2 not only has delayed initial ignition time by 23 s,but also severally shows 58.1%,23.1%and 44.4%lower smoke produce rate(SPR),THR and PHRR.The study on mechanism behind outstanding flame retardancy reveals that the improved heat resistance and flame retardancy of BN@CeO2/BCy composite are attributed to multiply effects induced by BN?CeO2 and its interaction with BCy resin;specifically,these effects come from BN(physical barrier)and CeO2(free radical trapping effect and catalytic char layer formation)as well as those from the synergistic effect of BN and CeO2.These excellent comprehensive properties of BN@CeO2/BCy composites demonstrate that BN@CeO2 is an environment-friendly and synergistic modifier for developing heat-resisting thermosetting resins with outstanding flame retardancy and smoke suppression.