Study On The Preparation And Performance Of Boron-containing Hybrid Phenolic Epoxy Resin

Epoxy resin is widely used in coatings,adhesives,electronic packaging materials,aviation,aerospace,military industry and other fields due to its excellent properties.However,with the development of science and technology,many fields have put forward higher requirements for the comprehensive performance of epoxy resin.In this paper,modified boron phenolic resin is used as the matrix resin,and a boron phenolic epoxy resin with strong thermal stability and good mechanical properties is prepared by a one-step method.The main content of the paper is as follows.1.The boron phenolic resin was prepared,and the material ratio and reaction conditions of the boron phenolic resin were studied.The optimal synthesis conditions of boron phenolic resin were determined based on the solid content,viscosity,free formaldehyde,free phenol,thermal stability and other properties of the resin.The molar ratio of phenol to formaldehyde is 1:1,the temperature of the addition stage is 60℃,the reaction time is 2h,the amount of catalyst is 1.5%,the amount of boric acid is the molar ratio of boric acid to phenol n(boric acid):n(phenol)=0.1:1,the reaction temperature in the polycondensation stage is 70℃,the pH is 4,and the reaction time is 1 h.2.Use 2-naphthol,silane coupling agents KH560,KH540,and melamine to modify the boron phenolic resin for heat resistance.The results show that when the molar ratio of melamine to phenol is 0.07:0.93 and 0.1:0.9,compared with the unmodified boron phenolic resin,the carbon residue rate of the cured resin is increased by 2%and 1.2%,respectively.3.Study methanol-modified boron phenolic resin,and use methanol’s polymerization inhibition to delay the degree of crosslinking reaction of boron phenolic resin.Orthogonal experiments were designed with free phenol and gel time as indicators to determine the best modification conditions.A methanol-modified boron phenolic resin with a gel time of 1557s,a thermal decomposition temperature of 465℃,and a carbon residue rate of 71.2%at 800℃ was prepared.4.Using methanol-modified boron phenolic resin as matrix resin,boron phenolic epoxy resin was prepared by a one-step method.Using methyl nadic anhydride as the curing agent,the mechanical properties and thermal stability of different modified resin cured products were studied.The results show that with the increase of boron content,the tensile strength and elongation at break of the cured resin first increase and then decrease.The boron phenolic epoxy resin with boron content of n(boric acid):n(phenol)=0.15:1 has the best comprehensive performance;the addition of epoxy diluent improves the elongation at break and tensile strength of the cured resin.Among them,the cured resin with 10%epoxy diluent has the best comprehensive mechanical properties.