In this study, aromatic sulfonated poly(sulfone-pyridine-amide) (S-PSPA) has been prepared via polycondensation of sulfonated monomer 1-(4-thiocarbamoylaminophenyl-sulfonylphenyl) thiourea and 2,6-pyridinedicarboxylic acid at high temperature. Mechanically robust and thermally stable hybrid membranes were prepared using nonfunctional and functional multiwalled carbon nanotube (MWCNT) i.e., S-PS/S-PSPA/MWCNT-NF and S-PS/S-PSPA/MWCNT via solution blending. Field emission scanning electron microscopy exhibited porous membrane structure for 0.1-0.5 wt% nanotube loading, whereas well-aligned functional MWCNT were observed in 1 wt% loaded sample. Increasing the functional nanotube content from 0.1 to 1 wt% increased tensile strength of functional S-PS/S-PSPA/MWCNT hybrids from 62.19 to 65.29 MPa compared with non-functional hybrid (53.34 MPa) and neat S-PS/S-PSPA. 10% decomposition temperature of S-PS/S-PSPA/MWCNT 0.1-1 was in the range 491-502 degrees C, while S-PS/ S-PSPA/MWCNT-NF showed relatively lower thermal stability (T-10 489 degrees C). Glass transition temperature of functional S-PS/S-PSPA/MWCNT was also higher (201-243 degrees C) relative to S-PS/ S-PSPA/MWCNT-NF (194 degrees C). Furthermore, functional MWCNT-based membranes had higher ion exchange capacity (IEC) 3.2-3.6 mmol/g and lower activation energies (95-36 kJ/mol). Novel functional membranes also revealed high proton conductivity 1.68-2.55 S/cm in a wide range of humidity at 80 degrees C higher than that of perfluorinated Nafion (R) membrane (1.1 X 10(-1) S/cm) at 80 degrees C (94% RH). (C) 2014 Society of Plastics Engineers