Study On The Preparation Of Microencapsulated Red Phosphorus Contained Intumescent Flame Rtardant And Flame Retarding And Smoke-suppressing Mechanism Of IFR Flameretarded Epoxy Resin

Microencapsulated red phosphorus (MRP) is a kind of inorganic phosphorus flame retardant with high flame retardance, wide range of applications, security and low-toxicity. Intumescent flame retardant (IFR) is one of the hot issues in recent years. MRP was used as acid source of intumescent flame retardant and was mixed with pentaerythritol (PER) and melamine (MA). IFR was used in epoxy resin (EP). The infulunce of IFR on flame retardance, smoke suppression performance and thermal decomposition kinetics of EP were studied systematically. These researches provided experimental parameters for the flame retarded EP.Red phosphorus was coated with melamine formaldehyde resin by in situ polymerization. The results showed that the moisture absorption of MRP was lowered from 13.1% of RP to 2.08%. The oxidation resistance of MRP was enhanced effectively. The consumption of sodium hydroxide of per gram MRP was lowered from 11.2 mg to 1.12 mg. The ignition point of MRP as high as 470℃. The application of IFR in EP was studied by limited oxygen index, smoke density, TG, scanning electron microscopy etc. The results showed that the optimum composition of IFR for EP is MRP:PER:MA=1.46:0.34:3.15 (mass ratio). The optimum content of IFR is 30%(based on EP). Limit oxygen index (LOI) was increased from 19.0%to 26.2%, tensile strength dropped from 32.40 Mpa to 22.27 Mpa, elongation at break fell from 9.94%to 7.80%. In order to improve the adverse effects of IFR on mechanical properties of EP, the improvement of coupling agents on mechanical and flame retarding properties of EP/IFR composites were studied. The results showed that:silane coupling agent (SCA) and titanate coupling agent (TCA) can effectively improve the mechanical and flame-retardant properties of EP/IFR. The tensile strength increased from 22.27 MPa to 26.02 MPa, LOI increased from 26.2%to 27.5 % under 2%SCA adding content. The tensile strength increased from 22.27 MPa to 26.75 MPa, LOI increased from 26.2%to 28.1%when add 3%TCA.In order to improve the adverse effects of IFR on smoke production of EP, the effect of different transitional metal oxides on the smoke suppression of EP/IFR/ SCA and EP/IFR/TCA composites were studied. The results showed that 2%CuO content has the best smoke suppression effect. the largest smoke density and smoke grade of EP/IFR/SCA decreased from 100%,83.39%to 81.12%,55.69% respectively, The largest smoke density and smoke grade of EP/IFR/TCA decreased from 100%,87.15%to 79.68%,53.05%respectively.Integral method was empolyed to analyze TG curves of EP and EP/IFR. The thermal decomposition process of EP and EP/IFR were studied. Non isothermal kinetics was used to study the apparent activation energy of EP and EP/IFR in various decomposition stages. The relationship between flame retarding properties and thermal degradation behavior was investigated. The analysis results showed that IFR changed the course of thermal degradation of epoxy resin. The apparent activation energy of the first stage of EP slightly larger than that of EP/IFR. The apparent activation energy of the second stage of EP/IFR greater than that of EP.