Preparation And Properties Of Multifunctional Flame Retardant Epoxy Resin Based On Bisphenol Acid

Epoxy resin has a series of advantages that other thermosetting plastics do not have,such as physical,mechanical and electrical insulation properties,bonding properties with different materials,and its application flexibility.Therefore,it can be made into composite materials applicable in various fields.At present,however,the most widely used commercial bisphenol A epoxy resin has a limited oxygen index(LOI)of only 19.8wt%,which is a flammable material,which greatly limits its application in some special and high-end fields.DOPO belongs to phosphorus flame-retardant structure,but it has become a hot research topic at home and abroad because of its advantages such as no harmful gas,high reactivity and outstanding flame-retardant effect.At present,the problems of DOPO additive epoxy resin are poor dispersion and compatibility between flame retardant and resin matrix.The problem of DOPO type epoxy resin curing agent is that there are few reactive sites and incomplete curing reaction.Chain extender can increase molecular weight,melt viscosity and molecular chain winding through the coupling chain of two or more polymers,and improve mechanical properties.TGIC is triglycidyl isocyanurate.The introduction of TGIC can avoid the problems caused by the above two forms,but it needs to overcome the difficulties of molecular structure design and epoxy resin synthesis process.In addition,commercial bisphenol A epoxy resin is a kind of human reproductive toxin and endocrine disruptor(bisphenol A)as the main raw material,which is potentially harmful to human body.Moreover,bisphenol A depends on the output of fossil resources.With the increasingly serious exploitation and exhaustion of fossil energy in the world,people pay more and more attention to the protection of resources.The epoxy resin industry urgently needs a kind of raw material which is abundant in resources,viable and biological to synthesize epoxy resin.From the point of view of molecular design,the multifunctional flame retardant epoxy resin TDBE based on bisphenol A was synthesized by three-step method,using bio-based platform compounds-bisphenol A,DOPO and TGIC as main raw materials.Then,the structure of the intermediate product and TDBE was characterized,and the molecular weight and epoxy equivalent of TDBE were measured.And the optimum curing conditions of TDBE/DDM system were determined.The new TDBE/DDM was compared with commercial epoxy resin DGEBA/DDM,and the cured resin was prepared by blending TDBE and DGEBA in the same increasing ratio.The thermomechanical and thermal stability,flame retardancy and flame retardant mechanism of TDBE/DDM were studied.The thermal stability,flame retardancy and mechanical properties of TDBE blend polymer were studied,and the feasibility of TDBE replacing DGEBA or partially replacing DGEBA was discussed.The results show that TDBE/DDM has mechanical properties and excellent fire resistance.The LOI value increased from 24.5% to 42.0%,and the UL-94 test level passed the V-0level.TDBE/DDM promoted the formation of a denser and fuller coke layer in the combustion process,further inhibited the volatilization of combustible gas,prolonged the ignition time of the composite and reduced the heat release.In the cone calorimeter test,the peak heat release rate(p HRR)decreased by 69.3%.Total heat release rate(THR)and total smoke exhaust rate(TSP)decreased by 51.4% and 17%respectively.In addition,the bonding strength of lap shear TDBE is 42.9 MPa,which is increased by 62.5%.This new multifunctional bio-based flame retardant epoxy resin provides a broader application prospect for high-performance materials.