Electrospun nanocomposite fibers were first produced from the PBS-DLS (70-30) and PBS-DLS-PEG (70-25-05) copolymers using cellulose nanocrystals (CNCs) at different concentrations (1%, 5%, and 10% by weight) to enhance the mechanical properties of the fibers. The copolymers were dissolved in a CHCl3/MeOH solvent mixture (7/3 v/v) at a concentration of 15 w/v%. CNC particles were dispersed into the solution using an ultrasonic bath at 60 °C for 60 minutes to ensure uniform dispersion. The electrospinning process was conducted by applying a voltage of 15 kV, maintaining a flow rate of 5 ml/h, keeping a distance of 20 cm between the needle and collector, and using a rounded needle with a gauge size of 23 G. To determine the optimum concentration of CNC in the copolymers, the resulting electrospun fibers were characterized morphologically using SEM and mechanically using an universal testing machine.