Boric Acid Pentaerythritol Condensation Polymer Modified Epoxy Resin Performance Study

The mechanical properties of epoxy resin,electrical insulation,adhesiveness and flexibility,are used in the military field,aerospace field and civil field.However,the oxygen index of epoxy resin is low(about 19.8 %),its flammability,its application is very limited,therefore,under certain conditions,epoxy resin is used for flame retardant.In the flame retardant composite materials,it is generally used flame retardant to improve the flame retardant of materials to prevent the material to be burned,so as to prevent the flame spread.At present,the flame retardant properties of modified epoxy resin,most applications of hanlu flame retardant,phosphorus flame retardant and inorganic flame retardant,but inorganic flame retardant has great effect on the mechanical properties of epoxy resin composites,and phosphorus flame retardant,hanlu flame retardant will cause certain pollution,therefore need to develop new flame retardant.Scientific research shows that organic boron flame retardant has the advantages of good flame retardant properties,low toxicity,low smoke.The research contents are as follows:(1)with boric acid and Pentaerythritol as raw material,the new organic boron flame retardant-suanji(BP)was synthesized.the optimal synthesis conditions were: boric acid:pentaerythritol = 1: 1,reaction at 100 ? for 7 hours;The obtained BP can be dissolved in water and ethanol;Bp initial decomposition temperature 368 ?,higher than the decomposition temperature of most polymers,can be used for polymer flame retardant.The results show that the maximum weight loss rate is 420.76 ?,carbon yield is 41.5,the decomposition temperature range is only 68 ?,and a large amount of coal bed can be generated in a narrow range of temperature,which is good flame retardant.(2)the BP/haiyinhuan resin system with different content was prepared,the viscositycharacteristics and coagulation characteristics of resin system were studied The cured product of BP/EP was prepared and its mechanical properties were tested.The results show that the dynamic viscosity curve of the resin system is U-shaped,and the viscosity of the low viscosity platform increases with the increase of BP content;At 105 ~ 125 ?,the BP/EP system has a low viscosity,suitable for forming operation.The experimental results show that the gel time of the resin system with BP is shorter under the same temperature,10 % BP reaction activation energy 73.33/mol,20 % BP reaction activation energy 62.89/mol,30 %BP reaction activation energy 58.89/mol;Increasing the amount of certain BP will help to reduce the activation energy of the system.The addition of BP can effectively improve the impact strength of epoxy resin,improve the toughness of epoxy resin,while BP addition of Hydantoin epoxy resin,the improvement of bending strength is not obvious.(3)the BP/EP resin system with different ratios was tested by dynamic DSC,and the characteristic curing temperature,reaction activation energy and curing kinetic equation were deduced;The results showed that the activation energy of each formula was calculated by DSC,the maximum activation energy of 10 % was 85.51/mol,and the reaction activation energy decreased with the increase of BP content,and the reaction activity increased;The kinetic equation of curing reaction of BP/EP was established by the combination of Kissinger,starink and crane equation.The characteristic curing temperature of BP/EP was obtained by extrapolation method.the curing process of BP/EP was established at 110 ? for 2 hours,solidified at 125 ? for 4 hours,and cured at 140 ? for 4 hours.(4)the flame retardant properties of BP/EP curing system were discussed.the results showed that the flame retardant property of cured product was improved obviously.with the increase of BP content,the oxygen index of cured product increased,the flame retardant property increased,when the content was 40 %,the oxygen index reached 30.5;With the increase of the polycondensation of pengsuanji,swelling degree decreased.Through the BP/EP resin TG test,the cured product of 10 % BP resin was carbon yield at 800 ?,74.4 %higher than that without BP With the increase of BP content,the carbon yield of the curedproduct increases,when the content reaches 40 %.Compared with the carbon yield of the epoxy resin without BP,the 220.6% increased the 220.6%,and the addition of BP can significantly improve the heat resistance of the cured product.Through scanning electron microscope(SEM),the combustion surface of BP(40 %)/EP was observed,the appearance of the combustion is dense,the inner surface is porous foam,is a typical intumescent flame retardant phenomenon.It is speculated that the main mechanism of the flame retardant of BP/EP flame retardant system is: forming vitreous coating layer,blocking effect;Decomposes dehydration,endothermic;Gas phase flame retardant.