Conversion of Low-quality Cotton to Bioplastic

Microplastic contamination generated by petrochemical products has become a global problem and led to a serious burden to our biosphere. The use of eco-friendly bioplastics can reduce the generation of microplastic wastes. In this study, we seek to make use of low-quality cotton fiber that lacks textile value as raw material to prepare bioplastic products. Although studies on bioplastics made of different biomaterials have been extensively documented, few studies focus on the direct use of low-quality cotton fiber. Therefore, we hypothesized that the conversion of this agricultural biomass (low-quality cotton fiber), could not only achieve homogenous, strong, and flexible bioplastic films by means of our improved preparation protocol, but also bring a high profit to cotton farmers and the cotton industry. In this study, bioplastic films were developed by dissolving 1% cotton fiber in N, N-dimethylacetamide/lithium chloride (DMAc/LiCl), followed by regeneration, glycerol plasticization, and hot pressing. The resulting films were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffractometer (XRD), Thermogravimetric analysis (TGA), and Deformation Recovery Analysis (DRA) to evaluate their physical, chemical and mechanical properties. The results from the material characterization suggest that although the resulting bioplastic films were amorphous with lower crystallinity, as compared to raw cotton cellulose, the physical and mechanical properties were significantly improved due to the plasticization and hot pressing operations. The plasticization using glycerol treatment enhances the deformation recovery capability and produces flexible bioplastic films. In addition, hot pressing operation reduces the surface roughness and improves the homogeneity of the bioplastic films. This study paves the way to use low-quality cotton fibers (usually sold at low price) to advanced bioproducts such as bioplastic. These materials produced from renewable sources could be a viable alternative to petroleum-based materials.