Preparation Of Kaolinite Complex And Its Application In Epoxy Resin:Flame Retardancy,Smoke Suppression And Aging Resistance

As a common thermosetting resin material,E-44 epoxy resin is often used in coatings and adhesives because of its good water resistance,corrosion resistance and high strength.However,epoxy resin is easy to burn at high temperature,releases a large amount of black smoke at the same time,and its strength decreases rapidly after aging,which limits its use and lays a huge hidden danger for the safety of people’s lives and property.Therefore,it is very necessary to carry out multi-functional modification of epoxy resin before use.In the work of this paper,kaol,which is rich in flame retardant elements such as silicon and aluminum and has a large specific surface area,is selected as the matrix,and other multifunctional nanoparticles are loaded on it to synthesize nanocomposites with unique properties.The research theme of this paper focuses on the synthesis of new kaol based additives and their multifunctional modification in epoxy resin matrix.It can be divided into the following three parts:（1）The multifunctional kaolite based compounds（AST@Kaol）were prepared by continuously loading titanium dioxide and silicon dioxide onto the surface of metakaolite（Kaol）,and then reacting with3-aminopropyl triethoxysilane（APTES）.The mixture was then introduced into E-44 epoxy resin（EP）to improve its flame retardancy,smoke suppression and anti-aging properties.The results show that just3wt%AST@Kaol can improve the limiting oxygen index（LOI）of EP composites to 27.3 from 25.3 of pure EP,and the heat release rate（HRR）,total exhaust gas volume（TSR）and smoke density（SD）can be reduced by 36.9%,14.3 and 19.9%respectively.The thermal stability and thermal oxidation of EP composites were enhanced.Meanwhile,the mechanism of flame retardancy,smoke suppression and aging resistance of EP containing AST@Kaol was also speculated.（2）By loading molybdenum sulfide（MoS₂）on the surface of acidified kaolite（A-Kaol）,a hybrid of MoS₂@A-Kaol was obtained.Then MoS₂@A-Kaol was introduced into epoxy resin（EP）to enhance the carbonization,smoke suppression and anti-aging.The results showed that3%MoS₂@A-Kaol can effectively lift the char residue from 13.2 of control EP to 21.9%.The limit oxygen index（LOI）increased to 27.1 with addition of 3%MoS₂@A-Kaol,and the smoke production rate was reduced 34.2%compared with the control EP in the cone calorimeter test.In addition,the anti-aging properties of EP composites have also been significantly improved with the addition of 3%MoS₂@A-Kaol.Especially,the presence of MoS₂@A-Kaol can obviously alleviate the decline of mechanical properties of EP composite,which exceeded 33%of the tensile strength and 300%of the impact strength after aging compared to control EP.Meanwhile,the thermal conductivity and dielectric properties meet the use requirements after adding filler.This work can provide a feasible way to fabricate a multi-functional hybrid material MoS₂@A-Kaol and its effect on carbonization,smoke suppression and anti-aging agent to EP.（3）A novel integrated intumescent flame retardant（IFR）was designed by reaction of 2,4-N-Tris（hydroxymethyl）methyl aminomethane（Tris）,cyanuric chloride（CNC）,and ammonium polyphosphate（APP）.The obtained product Tris-CNC-APP was used in epoxy resin.And MoS₂was grafted on the acidified kaolite molecules,the hybrid of MoS₂@A-Kaol was used as a synergistic flame retardant and smoke suppression agent.At the use of 7%Tris-CNC-APP/3%MoS₂@A-Kaol,the LOI value of the EP sample reached 32.1 and passed the UL-94 V-0 rating.In the cone calorimeter test,the total heat release（THR）and total smoke release（TSP）were about half reduced compared with the control EP sample.The tensile strength of the control EP sample reached 56.5 MPa;and impact strength was 3.1 KJ/m².After 340nm UV irradiation at 60^oC for 72 h,most mechanical lost,the sample became very brittle;with the tensile strength and impact strength decreased to25.7 MPa and 0.6 KJ/m²,respectively.However,for the sample containing 7%Tris-CNC-APP/3%MoS₂@A-Kaol,after similar UV aging,the tensile strength was 33.3 MPa;and the impact strength was 2.2 KJ/m².The reason was ascribed to the triazine groups in Tris-CNC-APP adsorbed some ultraviolet radiation,the EP was protected from UV aging.Tris-CNC-APP acted as a flame retardant and anti-aging agent synchronously.A feasible solution to realize high flame retardant grade and durable mechanical performance of EP products used outdoors with low filler loading was explored in this work.