Study On Preparation Of Expandable 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 insulation material.But EPS exists some obvious disadvantages, such as: relatively high thermal conductivity,intolerant aging, flammable, poor fireproof performance. In order to improve the insulationand flame retardant property of EPS, this paper prepared core-shell particles with the aerogelSiO₂as "nuclear" and polystyrene as "shell" by using super thermal insulation materials SiO₂aerogel and polystyrene, then seep foaming agent into the compound particle through the hotdipping method, finally prepared polystyrene/SiO₂aerogel composite through steam foammolding method. And it discussed the influence of the synthetic process of polystyrene/SiO₂aerogel core-shell particles, hot pressing impregnation process, composite particle foamingtechnology, got a preparation method of core-shell particles, prepared polystyrene/SiO₂aerogel composite insulation materials with low coefficient of thermal conductivity.This paper discussed preparation technology of polystyrene/SiO₂aerogel core-shellparticles, influence of the oil and water、dispersant system、mixing speed and SiO₂aerogel oncore-shell particles diameter was researched, the results show that: polystyrene/SiO₂aerogelcore-shell particles have small average particle size, and concentrate particle size distribution,when oil-water ratio1:4; In the dispersant system: organic dispersant （poly （vinyl alcohol）5%solution） three parts, inorganic dispersant （tricalcium phosphate）1.5parts; stirring speed500r/min; the adding amount of SiO₂aerogel2parts. And then analyse the microscopicmorphology of core-shell particles, discuss the factors of modes of dispersion, scatteredparticle size and add volume of SiO₂aerogel on nuclear shell; Analyzes the influence of SiO₂aerogel on glass transition temperature of composite particle, the results show:core-shellparticles of the glass transition temperature gradually reduce with increase of adding amountof the aerogel SiO₂.This paper do research on the impact of particle density and the foaming rate powerfulfactors: steam pressure and ventilation/time, optimizing the steam pressure is0.4MPa,ventilation for45s time prefoam process; Through the scanning electron microscopy （sem）analysis, comparing the different SiO₂aerogel add amount of composite particle size of the bubble hole after foam, and draw the conclusion that: with increase of the add amount of SiO₂aerogel, bubble hole diameter gradually decreased; Through the measurement for the thermalconductivity of different apparent density compound, determine the molded foam process ofpreparation for the best apparent density compound. First steps of heating: steam pressure is1.25MPa, ventilation time22s, second steps of heating: steam pressure is0.7MPa,ventilation time20s.In the end, this paper discussed the influence of SiO₂aerogel oncompound flame retardancy, concluded that:with the increase of SiO₂aerogel additionamount from0.4g to2.4g, extinguish time of composite board reduced from3s to0.5sunder the situation of same flame retardant additives. Through the horizontal flame testshowed that composite plate belongs to HF-1burning level.