Preparation and Anti-Flame Capability of Expandable Graphite
Subscript textFeasible conditions to get flame retardant expandable graphite (EG) with low initiation expansion temperature and high dilatability were obtained through orthogonal test and single factor experiment. EG with initiation expansion temperature of 148 ±2 °C and expansion volume of 550 mL/g can be prepared according to the mass ratio of C : KMnO4 : 98% H2SO4 : Na4P2O7 = 1.0 : 0.4 : 5.0 : 0.6 (H2SO4 should be diluted to thSubscript texte mass concentration of 80% before intercalation reaction), the reaction time is 40 min at 40 °C. Addition of 30% of the prepared EG to Liner Low-Density Polyethylene (LLDPE) can improve its limiting oxygen index LOI from 17.5% to 29.4%, and the synergistic anti-flame LOI of 20% EG with 10 polyphosphate (APP II) can reach to 31.2%. TG and DTA analysis was completed to discuss the anti-flame mechanism.