Parameters influencing electrospun nanofiber diameter of polylactide incorporated with cellulose nanofibrils and nanocrystals

The main purpose of this study was to investigate effects of various electrospinning parameters on the morphology and diameter of cellulose nanofibril (CNF) filled polylactide (PLA) nanofibers. For this purpose, first of all effects of three important electrospinning parameters; polymer solution concentration, solution feeding rate and collector distance to feeding tip were studied. Then, effects of using higher amount of CNF, effects of using cellulose nanocrystal (CNC) particles, and effects of adding potassium chloride salt were also investigated. It was observed that when optimum electrospinning parameters were determined, then it was possible to obtain almost “bead-free” morphology and “finest” average diameter of 232 nm for PLA/CNF electrospun fibers. Increasing values of feeding rate and collector distance parameters resulted in bead formation and thicker diameters. On the other hand, increasing CNF amount, using CNC particles and adding KCl salt, all resulted in further decreases in the diameter down to 152 nm; mainly due to increased charge density of the polymer solution. Moreover, in vitro degradation analysis of all types of electrospun nanofiber mats in a simulated body fluid revealed that increasing the immersion period increased their degradation rate in terms of “% weight loss”. It was also observed that, mats with fine diameter fibers had higher degradation rate.