Thermo-mechanically improved polyvinyl alcohol composite films using maleated chitin nanofibers as nano-reinforcement

In this study, maleated chitin nanofibers (MCNFs)-poly (vinyl alcohol) (PVA) composite films were fabricated to evaluate the reinforcement effect of MCNFs to PVA. Maleated chitin nanofibers (MCNFs) were prepared by esterification of alpha-chitin powder with maleic anhydride and 2 passes grinder treatment. The average diameter of MCNFs was about 10 nm. The PVA-MCNF composites films were prepared by solution casting technique at 0, 1, 3, 5, 10 and 15 wt% of MCNFs. The FTIR and XRD analyses revealed that, there were strong interaction between MCNFs and PVA. The nanocomposite films displayed nearly similar transparency level of PVA film suggesting that the MCNFs were dispersed at the nanoscale range. Both the DSC and TGA analyses have shown that, thermal stability of PVA was significantly enhanced upon inclusion of MCNFs. The tensile testing data also indicated that, the Young's modulus, tensile strength, elongation at break and toughness of PVA were increased by 71.87%, 41.47%, 49.10% and 261.20%, respectively through incorporation of 3 wt% MCNFs into the PVA matrix. The maximum swelling index of PVA film in deionized water (195%) was reduced to 141% for 3 wt% MCNFs containing composite film. The strong interfacial interactions between MCNFs and PVA were the decisive factors for the betterment of PVA properties. Generally, this study demonstrates a substantial approach in making thermo-mechanically stable and less water sensitive biodegradable nanocomposite films to be applied in making flexible packaging and biomedical materials. Graphic abstract

Automated summary

This study fabricated MCNFs-PVA composite films and demonstrated the reinforcement effect of MCNFs, showing good dispersibility and thermal stability, significantly enhancing the mechanical properties and water resistance of PVA.