Development of environmentally friendly composite packaging films from safflower<i> (Carthamus</i><i> tinctorius</i> L.) plant wastes

Safflower, a widely utilized industrial plant in the production of vegetable oil and biodiesel, generates safflower heads as waste during seed oil extraction, which is known to be rich in cellulose. In this study, the production and characterization of environmentally friendly biocomposite and nano-biocomposite packaging films with a reduction in the utilization of fossil-based materials were focused on. The materials of interest were cellulose (SC) and cellulose nanocrystals (SNC), which were derived from safflower head waste (SAW). The fillers SC and SNC were subjected to analysis to investigate changes in their chemical structure (FTIR), degree of crystallinity (XRD), and surface morphology (SEM and AFM). It was observed that SNC, obtained from SC, exhibited a higher crystallinity level (62%) compared to SC, and displayed mostly spherical morphology with an average diameter of approximately 100 nm. The production of low-density polyethylene (LDPE) based biocomposite and nanobiocomposite packaging films filled with SC (5%-20%) and SNC (0.1%-1.5%) was conducted in two stages: compound production using a twin-screw extruder and blown film extrusion. The incorporation of SC resulted in a 75% decrease in the mechanical properties of LDPE/SC biocomposite material. However, the addition of SNC proved to be relatively effective in maintaining the mechanical properties of LDPE/SC/SNC nano-biocomposite films. Furthermore, the LDPE/SC/SNC nano-biocomposite films exhibited increased crystallinity and gas permeability compared to LDPE, which can be attributed to the effective interaction between LDPE and the fillers (SC and SNC).