Effect of processing parameters on the electrospinning of cellulose acetate studied by response surface methodology

Cellulose acetate (CA) is the acetate ester of cellulose produced from cellulose via the process of acetylation. Currently, electrospinning has become a widely used technique to produce CA nanofibers for potential applications such as filtration, medical dressings, and food packaging. Being biodegradable and biocompatible, CA nanofibers bring additional advantages for these applications, e.g., high surface area, high porosity, and light weight. The quality of the CA nanofibers, which can be characterized by the prevalence of fiber defects, pore size, and fiber diameter, directly affects their performance. Fiber quality is, in turn, directly determined by the electrospinning process parameters. Therefore, in this project, we aimed to investigate the effect of electrospinning parameters, including CA concentration, voltage, and spinning distance, on the electrospinnability of CA nanofibers and fiber diameter, using process optimization principles and response surface methodology. Certain process parameters, including solvent (acetone), needle diameter (gauge 22, inner diameter 0.413 mm), temperature (20 °C), and feed rate (2 mL/h), were kept constant throughout the experiment. Preliminary experiments were conducted to determine the extreme conditions of each parameter and to define a working boundary. Then, trials of electrospinning CA nanofibers were conducted following a 3-factor, 3-level Box-Behnken design within the predetermined range. CA nanofibers morphology was characterized by scanning electron microscope (SEM) and ImageJ software to obtain their mean diameter. The mean electrospun fiber diameters fell into the range from 404 to 1346 nm and increased with increasing CA concentration. The fiber diameter was impacted less significantly by the other two parameters, i.e., voltage and spinning distance.