| Epoxy resin has the advantages of high adhesive strength,excellent dimensional stability.But its use is limited by the defect of flammability.Its flame retardant performance can be improved by adding intumescent flame retardant,but it can only be added in large quantities to achieve the ideal flame retardant effect,which affects the mechanical properties and mechanical properties of epoxy resin,so it needs to adopt synergistic flame retardant technology.After the simultaneous exfoliation of hexagonal boron nitride and flake graphite,the Nano-hexagonal boron nitride/graphene not only has the advantages of super high specific surface area and green pollution-free,but also the unique sheet structure of the exfoliated hexagonal boron nitride/graphene reduces the influence of external heat source on the epoxy resin,which can be used as a synergistic flame retardant to enhance the flame retardant performance of epoxy resin.Therefore,this work explores the effect of microwave process for simultaneous exfoliation of flake graphite and hexagonal boron nitride,the best exfoliated Nano-hexagonal boron nitride/graphene as synergistic flame retardant and intumescent flame retardant compounded with epoxy resin,and explores the effect of different components of Nano-hexagonal boron nitride/graphene on the thermal stability performance and flame retardant performance of epoxy resin.Epoxy resin flame retardant composites by studying the thermal degradation kinetics to obtain their flame retardant mechanism as follows:(1)The Nano-hexagonal boron nitride/graphene/intumescent flame retardant/epoxy resin composites prepared by mechanical blending with epoxy resin and intumescent flame retardant using 16 different sets of process parameters for simultaneous microwave exfoliation of scaled graphite and hexagonal boron nitride,and the optimal set of microwave process parameters was selected based on the different thermal stability properties of the epoxy resin composites,while the microwave exfoliation process using this set The study showed that the best microwave stripping process was the first microwave power of 800 W for 5 min,the second microwave power of 240 W for 2 min,and the Nano-hexagonal boron nitride:graphene component ratio of 1:1 and3:5,respectively.The overall thermal stability performance was better when the ratio of nanohexagonal boron nitride:graphene was 1:1 and 3:5 respectively.(2)The flame retardant properties of the nano-hexagonal boron nitride/graphene/intumescent flame retardant/epoxy resin flame retardant composites were compared,and the study showed that the synergistic effect of the nano-hexagonal boron nitride/graphene composite to exoxy resin/intuescent flame retardant composites was more satisfactory when the ratio of Nanohexagonal boron nitride:graphene was 3:5 in terms of smoke release performance and dilution of CO gas.The total smoke emission rate was reduced by 31.99% and 21.80% compared with epoxy resin and epoxy resin/intumescent flame retardant composites,respectively,and the maximum CO gas yield was reduced by 30.77% compared with epoxy resin.(3)The Nano-hexagonal boron nitride/graphene/intumescent flame retardant/epoxy resin flame retardant composites were subjected to non-isothermal thermal degradation kinetic studies,and the Kissinger method and Flynn-Wall-Ozawa method were used to calculate the changes of their activation energies,and the Malek method was used to determine the mechanism functions f(?)of the three materials,respectively.It was found that: the patterns presented by the thermal decompoition of the above three materials at different heating rates were not affected by this and all remained consistent;the mechanism functions of the above three materials belonged to the Avrami-Erofeev equation and the mechanism of the functions were consistent with random nucleation and subsequent growth. |
PDF Full Text Request