Mechanical and thermal properties of carboxymethyl fibers (CMF)/PVA based nanocomposite membranes

•Addition of CMF to swollen PVA at 93% RH increased E-modulus 7 fold.•The maximum swelling is achieved at low CMF content in PVA matrix.•Highlight 1 and 2 make PVA-CMF membranes promising for CO2 separation.•The XRD and FTIR results revealed the good compatibility among PVA and CMF.•Addition of CMF has no effect of thermal properties of PVA/CMF membranes.