The Study On The Preparation Of Flame-retardant Expandable Graphite

In order to prepare the expandable graphite for the expansion flame retardant system of polystyrene foam insulation board, In this article, the raw material is fine flake graphite with the low carbon content, first using HF soaking method improved the carbon content of flake graphite, then the chemical oxidation method and electrochemical oxidation method were used respectively to prepare the expandable graphite, and through many experiments to find out the optimum process conditions of this tow different methods. Experiments show that: 1. The best soaking time in the HF is 120 minutes and the graphite carbon content can be purified to 99.42%; 2. Using chemical oxidation to prepare expandable graphite, after the oxidation of H2O2, the best proportion of raw materials is C: H2SO4: K2Cr2O7 = 1:4:0.16(g: ml:g), the results show that under ultrasonic concussion(35℃,1000w) the optimum reaction time is 1 hour, and the expandable volume is 165 ml/g; 3. the best conditions for using electrochemical oxidation process to prepare the expandable graphite is: the flake graphite’ mass is 10 g with 0.8 g K2Cr2O7, voltage is 2.5V, current is 0.3A, the optimum reaction time is 3h, the expandable volume is up to 248 ml/g; 4.Using fine flake graphite can be better coating the EPS bead. Combing with the XRD, SEM testing means to test the flake graphite, expandable graphite, we research and analysis of the microstructure of their structure. This article has practical guiding significance to the production technology of using low carbon content and fine flake graphite to prepare the expandable graphite, and there are the rich theory value and the important practical significance to the research development of expansible graphite’s preparation by using chemical oxidation method and electrochemical oxidation method.