| Carbon nanotubes (CNTs), due to their unique structure, have excellent mechanical,electrical, and thermal properties. As reinforcing filler, CNTs seem to offer quite promisingpotential for application, in the field of polymer nanocomposites material. Using carbonnanotubes to enhance the flame retardant properties of polymer nanocomposites has become aresearch hotspot. Because of flame retardant research for carbon nanotubes in polymernanocomposites relatively late, the flame retardant properties and mechanism in different firescenarios remains unclear.Polymethyl methacrylate(PMMA)/multi-walled carbon nanotube nanocomposites havebeen synthesized via the in-situ method，with multi-walled carbon nanotubes (MWNT) andmethyl methacrylate (MMA) mixture. How to improve MWNT dispersion in MMA monomer,as well as the factors affecting the synthesis of PMMA and MWNT/PMMA composites, areresearched. Thermo-gravimetric analyzer is used to study the thermal stability of thecomposite. The parameters including heat release rate, ignition time, CO yield, CO2yield areobtained and compared at different heat fluxes, using cone calorimeter. Horizontal verticalcombustion apparatus is used to study the composites flame propagation speed and flameretardant grade.The results show that ultrasonic, mechanical stirring, a certain amount of surfactant worktogether, is more advantageous to disperse MWNT. The main factors affecting the synthesisof pure PMMA are initiator content, the pre-polymerization time and temperature, thepolymerization temperature; CNTs added, changes prepolymerization time andpolymerization temperature of the composites. MWNT can not significantly increase thethermal stability of composites; adding1%weight of MWNT into PMMA composites canreduce the peak of heat release rate to a large extent, as well as inhibiting the drippingbehavior very well in the combustion process. From the combustion test results,MWNT/PMMAcomposites are gas-phase and condensed-phase flame retardant. |
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