Characterization of Biodegradable Films from Holocellulose of Natural Polymers via Electrospinning

The growing demand for sustainable materials has driven the search for biodegradable alternatives to conventional plastics. This study investigates the use of cashew industry waste (Anacardium occidentale), an abundant agro-industrial byproduct, in the production of biodegradable films through the electrospinning technique, in combination with natural polymers such as polylactic acid (PLA) and polycaprolactone (PCL). The objective of this work is to optimize electrospinning parameters for each polymer, including variations in solution concentration, solvent type, flow rate, and applied voltage, as well as the treatment of cellulosic material for incorporation into polymer solutions for film production. The methodology involved preparing PLA and PCL solutions (10 and 15% w/v) using a system of acetic acid and formic acid (9:1 ratio) and in analytical-grade acetone. Electrospinning was carried out under different conditions to determine optimal parameters, and alkaline treatment of the natural raw material was performed with NaOH solutions at 2% and 5% v/v. Film characterization was conducted by Thermogravimetric Analysis (TGA), Derivative Thermogravimetry (DTG), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM). Thermal analysis results allowed classification of the fibers according to thermal stability and confirmed complete solvent evaporation during electrospinning, with single-stage mass loss for both polymers, corresponding to 100% for PLA and 90% for PCL, within their respective degradation temperature ranges (360 °C for PLA and 425 °C for PCL). SEM results enabled the evaluation of the effects of different parameters on surface morphology and revealed the successful production of nanometer-scale fibers for PLA electrospun in acetone and PCL electrospun in acetic acid/formic acid.