Potential Value of Konjac Glucomannan Microcrystalline/Graphene Oxide Dispersion Composite Film in Degradable Plastics

Abstract

Konjac glucomannan (KGM) is a promising bio-based material that can effectively mitigate the global petroleum-based plastic pollution exacerbated by the responses to COVID-19. This study first acidified KGM to obtain KGM microcrystals (MKGM) with a relatively low molecular mass. Next, different volumes of graphene oxide (GO) dispersions were mixed with MKGM to prepare composite films via physical cross-linking using glycerol as a plasticizer. The UV barrier capability, mechanical strength, thermal stability, and water resistance of these films were subsequently assessed. GO enhanced the tensile strength of the polysaccharide, while limiting its toughness. Thus, the tensile strength of the MKGM film improved from 7.80 MPa to 39.92 MPa following the addition of 12 mL of GO dispersion, and the elongation at break decreased from 46.31% to 19.2%. A morphological study revealed that the addition of different volumes of GO caused the composite films to exhibit various degrees of porosity and an enhanced water barrier capability. Introducing GO also improved the UV barrier capability and thermal stability of the composite film. Meanwhile, the composite films exhibited excellent degradation properties. Therefore, composite films prepared via the acidification of KGM and the incorporation of GO are suitable for extensive utilization in degradable plastics.