Study On The Suspension Polymerization Process Of Graphite/Polystyrene

Along with China’s energy conservation and emission reductionand the policy of constructing economical society, expandable polystyrene(EPS) foam is developing rapidly in the field of thermal insulation materials. However, since EPS foam is extremely flammable, its application is limited in the fields of heat preservation in high-rise buildings. As a result of the lamellar structure, graphite can reflect infrared like a mirror, and further reduce the coefficient of thermal conductivity, at the same time, the graphite is all-carbon molecules, it can improve the flame retardant performance of EPS.This thesis mainly studies the suspension polymerization process of G-EPS to provide an experimental basis on synthesizing low thermal conductivity and flame-retardant foam materials.The graphite is all-carbon molecules. Graphite surface energy is quite low, and the vast majority of polymer compatibility is poor. It is difficult to good dispersed in polymer matrix. The graphite is modified through a method that based on diazotization to improve its compatibility with the polymer matrix. In this method, a specific kind of compoundthat containing diazo groupis prepared, and is used to modify graphite through carbene reaction. The process and result of the synthesis of the compound that containing diazo group is tested by 1H NMR, 13 C NMR and FT-IR. The chemical change of the modification of graphite is test ed by FT-IR, Raman and XPS. The result of the modification of graphite can be tested by the change of its dispersity in styrene and the mixture of styrene and water.The graphite/polystyrene spherulite is synthesized by in-situ suspension polymerization. This paper also studies the process conditions of the suspension polymerization of polystyrene. The influence of process conditions towards particle sizeand molecular weight distribution is confirmed by using different amount or degree of dispersing agent, surfactant, initiator, nucleating agent, modified graphite as well as stirring speed and water-oil ratio. The best process conditions include these items: the amount of dispersing agent is 1.78%(The following are for quality percentage), the speed of stirring is 310 rpm, the amount of surfactant is 0.039%, the amount of nucleating agent is 3%, the amount of initiator is 5%, The amount of modified graphite is 8%. Through this method, graphite/polystyrenespherulite is synthesized with appropriate and centralized particle size which 90.26% of the particles are between 0.59-1.4mm. The graphite/polystyrene spherulite is prepared by two step method. And the graphite/polystyrene spherulite is foamed to get the graphite/polystyrene foam, and the abscess is well-proportioned. This paper will direct the industrial production of low thermal conductivity and flame-retardant EPS foam materials.