Carbon Nanotubes Doped Poly (arylene) Ether Copolymerised Multiblock Based Proton Exchange Composite Membranes for Fuel Cell Application

The article reports the synthesis of nanophase-separated multiblock poly(arylene ether ketone sulfone) copolymers. A series of hydrophobic oligomers end-capped with decafluorobiphenyl (DFBP) group was reacted with disulphonated poly(arylene ether ketone) copolymer containing 4, 4′-bis (4-hydroxyphenyl) valeric acid moieties to synthesize multiblock copolymer. The copolymers were characterized using 1 H-NMR, 13 C-NMR, 19 F-NMR spectroscopy and Gel Permeation Chromatography. The membranes with high dimensional and thermal stability were obtained through solution casting method. The multiblock copolymers were crosslinked with 6F-bisphenol-A (6F-BPA) based novolac epoxy resin. The functionalized multi-walled carbon nanotubes (f-MWCNTs), in 0.5, 0.7, and 0.9 wt.%, were also incorporated into the polymer matrix in order to prepare nanocomposite membranes. Polymer nanocomposite membranes showed high oxidative stability, and proton conductivity. The surface morphology and composition of polymer nanocomposite membranes were studied using field emission-scanning electron microscopic (FE-SEM), and high-resolution transmission electron microscopic (HR-TEM) techniques. The fuel cell related parameters such as water uptake, proton conductivity, ion exchange capacity, oxidative stability, and methanol permeability were also evaluated. The thermal performance and mechanical behavior of the synthesized polymer nanocomposite membranes were also studied. The nanocomposite membranes showed better fuel cell performance as compared to the pristine membranes.