Study On Preparation Of Expandable Flame Retardant Polystyrene/SiO₂Aerogel Core-shell Particles And Foam Molding Technology

EPS with small bulk density,good mechanical strength and toughness, chemicalresistance, waterproof, easy to form, is a very common building thermal insulationmaterial. But EPS exists some obvious disadvantages, such as: relatively high thermalconductivity, intolerant aging, flammable, poor fireproof performance. In order toimprove the insulation and flame retardant property of EPS, this paper preparedcore-shell particles with the aerogel SiO₂as "nuclear" and polystyrene as "shell" byusing super thermal insulation materials SiO₂aerogel and polystyrene, then seepfoaming agent into the compound particle through the hot dipping method, finallyprepared polystyrene/SiO₂aerogel composite through steam foam molding method.This paper discussed the influence of the synthetic process of polystyrene/SiO₂aerogel core-shell particles, hot pressing impregnation process, composite particlefoaming technology, certained out a preparation method of core-shell particles,prepared polystyrene/SiO₂aerogel composite insulation materials with low coefficientof thermal conductivity.This paper discussed preparation technology of polystyrene/SiO₂aerogelcore-shell particles, influence of the oil and water、dispersant system、mixing speedand SiO₂aerogel on core-shell particles diameter was researched, the results show that:polystyrene/SiO₂aerogel core-shell particles have small average particle size, andconcentrate particle size distribution, when oil-water ratio1:4; In the dispersantsystem: organic dispersant （poly （vinyl alcohol）5%solution） three parts, inorganicdispersant （tricalcium phosphate）1.5parts; stirring speed500r/min; the addingamount of SiO₂aerogel2parts.This article also uses the two-step preparation containing flame retardantpolystyrene foaming agent/SiO₂aerogel core-shell composite bead, adding flameretardants add process for polymerization phase, and then by dipping, pretest, curingand molding flame retardant was prepared by styrene/SiO₂aerogel foam board. Bydesigning different flame retardants species and content of comparative experiments,research on the polystyrene/SiO₂aerogel composite foam flame retardant performance, mechanical strength and thermal insulation performance, the results show that simplyusing HBCD for flame retardant, when HBCD usage more than6%, the compositefoam board can achieve better performance of flame retardant, self-extinguishing timeof4.1seconds, the oxygen index reaching18.8%; Flame retardant synergistic agent ofSb₂O₃can reduce the dosage of HBCD, when HBCD/Sb₂O₃in1:2¹:1materialself-extinguished time in4.5seconds, the oxygen index reaching19.1%;Especiallywhen HBCD:Sb₂O₃=2:1, the flame-retardant effect is best, self-extinguishing time of2.6seconds, the oxygen index reaching20.3%; When HBCD and Sb₂O₃content underthe condition of invariable, inorganic flame retardant with Al（OH）₃with contentincreased, the composite foam sheet products of flame retardant performance issignificantly improved, when its content is2.0%, the flame retardant properties ofmaterials to achieve the highest. The coefficient of thermal conductivity of compositeboard with flame retardant agent and with the increase of adding amount of increase;Compressive strength decreases with increasing the amount of flame retardantsHBCD added, when the flame retardant by Sb₂O₃replace part of HBCD, compressivestrength increased with the increment of replacement.This article also uses the thermosetting phenolic resin/Al（OH）₃front flameretardants for synthesis of polystyrene/SiO₂aerogel core-shell composite beadcoating processing, and focuses on thermosetting phenolic resin/Al（OH）₃in flameretardant liquid thermosetting phenolic resin and Al（OH）₃both content on thecomposite flame retardant properties of EPS material, the influence law of mechanicalstrength and heat preservation performance. Through mixing, stirring, drying andmoulded foam molding the way of the phenolic resin/Al（OH）₃fire retardant liquidcoating on the nuclear shell beads of coating process and the optimal coating processparameters, the flame retardant properties, mechanical strength and thermal insulationproperties are excellent composite flame retardant EPS material. To get oxygen indexof flame retardant EPS composite materials in the test, compression strength test,coefficient of thermal conductivity test data show that the content of phenolic resin（EPS） relative to the same conditions, the content of Al（OH）₃is lower than15g（relative to the compound EPS）, Al（OH）₃content is higher, the composite flameretardant properties of EPS material, the better, and in the content of Al（OH）₃to15g peak, when the lower mechanical strength, thermal insulation performance is poor;When the content of Al（OH）₃is higher than15g, Al（OH）₃content is higher, thecomposite flame retardant properties of EPS material is lower, the lower mechanicalstrength, thermal insulation performance is poor; In the Al（OH）₃content under thesame conditions, the higher the content of phenolic resin, composite flame retardantproperties of EPS material, the better, the higher mechanical strength, thermalinsulation performance.