Background and Objective: Some patents have reported the centrifugal spinning method
which utilizes the centrifugal force produced by a high speed rotating device to fabricate fibers from
polymer melts or solutions. Recently, with the development of technologies, centrifugal spinning was
employed to produce ultrafine fibers and nanofibers. In order to improve the equipment and technology
of centrifugal spinning and obtain finer fibers, it is important to model the polymer drawing of the
Methods: The polymer drawing in the centrifugal spinning is modeled and simulated. The force balance
equation and heat transfer balance equation are established after analyzing the motion and heat
transfer of the polymer melts. These nonlinear equations are solved based on the least square method
to obtain the radius of excircle and the shape of streamline. A fourth order Runge-Kutta method is utilized
to obtain the diameter and temperature of the threadline because there are initial value problems
of first order ordinary differential equations. Streamlines and diameter of polymer melts at different
viscoelasticities and different spinning temperatures are obtained. The simulation results are compared
with the measured results to verify the polymer drawing model.
Results: The viscoelastic force in the centrifugal spinning changes constantly at a fixed rotation speed
of the rotating spinneret. As the spinneret is rotating, the radius of excircle R1 increases slowly when
the time passes, which means the viscoelastic force decreases slowly. The change of the viscoelastic
force accelerates the increase of the radius vector. The simulation results show that the threadline diameter
under the condition of changing viscoelastic forces is smaller than that under the condition of
fixed visoelastic forces. The temperature of the polymer melts decreases faster under the condition of
changing viscoelastic forces than that under the condition of fixed visoelastic forces. The threadline diameter
decreases with the increase of the rotation speed. Higher initial polymer temperatures yield
smaller fiber diameters.
Conclusion: The polymer drawing in the centrifugal spinning is modeled and simulated. The simulation
results tally with the measured results confirming the effectiveness of the polymer drawing model.
The simulation results show that the change of the viscoelastic force is favorable to the polymer drawing
and both larger rotation speeds and higher initial polymer temperatures can produce finer fibers,
which lays a good foundation for the computer-assisted design of the centrifugal spinning.