This study investigates the effects of time and diameter on the final scission length of the electrospun polystyrene (PS) fibres, whereby the fibres were ultrasonicated for 1, 2, 3, 4, and 8 minutes. The ultrasonic probe stimulates bubble cavitation followed by bubble implosion as scission occurs. Factors affecting the scissionability of the electrospun PS fibres are primarily the diameter of the fibre and the sonication run time. The scission final fibre length range is approximately 23.7 µm to 1.1 µm. SEM images show that the fibre breaks into shorter lengths as sonication run time increases. Conversely, fibre diameter exhibits a positive relationship with fibre length. The model gives an R-squared value of 0.44 and 0.59 for linear and nonlinear regression, thus suggesting that the non-linear model provides a better fit for the data. The validation of the model is achieved by conducting a hypothesis test. Through hypothesis testing, the mean of the experimental average final length value and the predicted average fibre length from the regression model were not significant, indicating that the model can generally predict a relatively accurate average final fibre length value. The model derived from this study enables researchers to estimate the time required to sonicate the PS fibre (with a specific diameter) to achieve the short fibre length needed in their application. As research progresses, refining the model and incorporating additional parameters will be essential to ensure the broad reliability and applicability of these models across a variety of practical contexts. [ABSTRACT FROM AUTHOR]