Study On Preparation Of Aerogel/Polystyrene Core-Shell Composite Particles In Mini-Emulsion Polymerization Method And Foam Molding Technology

Nowadays traditional XPS heat preservation material already haven’t satisfied the currentneeds because of their higher coefficient of thermal conductivity and poor flame retardancy.SiO₂aerogel is a super insulation materials, appeared in recent years.it will have hugepotential for growth if it is used in Construction insulation field. But it’s water resistance ispoor and strength is low. So Developed a new and effective insulation material, compoundingof PS,it has great social and economic significanceThis article use styrene/silicon aerogel/hexadecanol/water as the main system. Weprepare homogeneous steady fine emulsion using ultrasonic dispersion. It was studied by theorthogonal test and single factor experiment method that the influence of factors to theperformances of the products such as appropriate proportion of polymerization, ultrasonicpower, ultrasonic time, dosage of initiator, reaction temperature, PH value. The experimentalresults show that the coated rate of compound particle increases as the SiO₂/St ratio ofsystem increases, then decreases. When SiO₂/St is1:20coated rate reaches the maximum,66.1%. Composite particle conversion increases as polymerization temperature increases.When the temperature is75℃,the conversion reaches the maximum,63.1%.We found the bestproportion of polymerization and the optimal processing parameters is, SiO₂/St for1:20,ultrasonic power for400W, ultrasonic time of30min,, the response time for10h, reactiontemperature for75℃,the reactionproducts was detected through the SEM, TEM andcoefficient of thermal conductivity detector. The new type composite micro-sphere materialwas found exactly possessing the structure whose core consisted of the SiO₂aerogel particle,and its shell consisted of organic polystyrene. It’s coefficient of thermal conductivity isreduced than pure polystyrene materials.Next step, we use the above core-shell nanocomposite materials as raw material formolding foam in homemade mould. It was studied that foam molding principles and theinfluence of process parameters to the performances of the insulation boards such as moldingpressure, temperature, pressure and unloading time. he experimental results show that density of the board decreases as polymerization temperature increases，then increases. Bubblediameter decreases gradually as the foam pressure increases. The best p optimal processingparameters is molding temperature for135℃, molding pressurefor200kg/cm2, pressureunloading time for25min.Through mechanical properties and the coefficient of thermalconductivity detection, according to the national standard we found that the performances ofcomposite insulation board meet the need of practical use，and it’s compressive strength andcoefficient of thermal conductivity is better than the existing polystyrene foam insulationboard.