Carboxyl-functionalized Nanocellulose Reinforced Nanocomposite Proton Exchange Membrane

Nanocellulose(NCC) was prepared through the acid hydrolysis of microcellulose(MCC) and was reacted with maleic anhydride to obtain carboxyl-functionized nanocellulose(MA-NCCs). The presence of −OH and −SO3H on the surface of rod-like MA-NCC was confirmed by Fourier transform infrared spectrometry(FTIR). Sulfonated poly(aryl ether ether ketone ketone)(Ph-SPEEKK) was synthesized with bis(4-fluorophenyl-methanone) and 2-phenylhydroquinone as monomer. MA-NCC/Ph-SPEEKK nanocomposite membranes with different MA-NCCs content were prepared, and their properties were characterized. Compared with Ph-SPEEKK, MA-NCC/Ph-SPEEKK nanocomposite membrane showed better mechanical and thermal properties and higher proton conductivity. The proton conductivity of the composite membrane with 4%(mass fraction) MA-NCCs under 80 °C was 0.095 S/cm. And its tensile strength reached 30.3 MPa, which was 21.2% higher than that of Ph-SPEEKK pure polymer membrane.