Study of ex-situ and in-situ PMMA/-COOH functionalized MWNT composites

Polymer composites based on poly(methyl methacrylate)/ carboxylic acid group functionalized multi-wall carbon nanotubes (PMMA/MWNT), were prepared by the exsitu and in-situ technique with 0.05% wt loading of the CNT. Nanocomposite films were fabricated by solvent casting method. Electrical conductivity of nanocomposites and the base PMMA polymer was measured. The different percolation thresholds were found for the composites and resin samples which were found to be related to the method employed. The neat PMMA samples prepared by the same methods showed complete insulating behaviour. Ex-situ technique leads to improved electrical conductivity. Wide angle XRD study also supports that the functionalization of MWNT affects the interfacial bonding of PMMA and MWNT resulting in better dispersion. Thermogravimetric analysis show that the amount of main chains decomposition of the in-situ composite is lower than that of pure PMMA and the ex-situ composite.