Mechanical, thermal and swelling properties of phosphorylated nanocellulose fibrils/PVA nanocomposite membranes

[Display omitted] •Addition of 6% nanocellulose to swollen PVA at 93%RH increased E-modulus 7 fold.•The maximum swelling is achieved at low nanocellulose content in PVA matrix.•Highlight 1 and 2 make PVA-nanocellulose membranes promising for CO2 separation.•The crystal structure of PVA was affected by addition of nanocellulose.•Crystallinity of PVA composite membranes increased with addition of nanocellulose. Cellulose nanofibrils (CNF) have strong reinforcing properties when incorporated in a compatible polymer matrix. This work reports the effect of the addition of phosphorylated nanocellulose (PCNF) on the mechanical, thermal and swelling properties of poly(vinyl alcohol) (PVA) nanocomposite membranes. The incorporation of nanocellulose in PVA reduced the crystallinity at 0%RH. However, when the films were exposed to higher humidities the crystallinity increased. No apparent trend is observed for mechanical properties for dry membranes (0% RH). However, at 93% RH the elastic modulus increased strongly from 0.12MPa to 0.82MPa when adding 6% PCNF. At higher humidities, the moisture uptake has large influence on storage modulus, tan δ and tensile properties. Membranes containing 1% PCNF absorbed most moisture. Swelling, thermal and mechanical properties indicate a good potential for applying of PVA/phosphorylated nanocellulose composite membranes for CO2 separation.