Developing a novel konjac flour/poly-vinyl alcohol composite film: Preparation, properties and characterization

Developing bio-based plastic has become an important strategy for solving environmental pollution. In this study, konjac flour (KF) and poly-vinyl alcohol (PVA) as main film-forming substances with added citric acid (CA), glutaraldehyde (GA) and glycerin, were used to prepare bio-based composite films via solution casting. How the PVA polymer amount affected the composite films including mechanical performance, structural properties and morphology was investigated. The results revealed that PVA polymer could obviously improve the mechanical property of the films, and the addition of 25% PVA based on KF mass when CA, GA and glycerin were fixed, was demonstrated as the optimal amount, maintaining an excellent tensile strength (TB) and elongation at break (EAB). Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD) results indicated the successful cross-linking reaction between PVA and KF, and some further proofs could be confirmed from scanning electron microscopy (SEM) and thermogravimetry (TG). After modification with PVA, the cross section of the KF/PVA composite film was more dense and uniform, implying that PVA was well fused with KF system. Meanwhile, the films modified with PVA presented a good thermal resistance ability. This work provided an effective pathway for preparing KF/PVA composite films with improved mechanical properties, which may be an alternative way for using konjac flour.