rotary-jet spinning in obtaining thin fiber mats evolved
merely in the past couple of years, the aforementioned reports
being some of the very few founded in the literature survey.
The main difference of our proposed system as compared
with other rotary-jet spinning equipments consists in the fact
that it allows the control of solvent evaporation by the use of
a cooling/heating gaseous flow in the spinning chamber that
surrounds the rotating active part. Also, the gaseous flow
may be evacuated through an exhaust blower. Besides the
surface tension of polymer solution and solvent vapor
pressure, the evaporation speed and medium saturation with
vapors represents very important parameters in the formation
of continuous, low diameter fibers and uniform matrices and
could be controlled by varying the flow rate and temperature
of gaseous environment. The influences of other processing
variables like distance from the centrifugal axis to the
collector, rotational speed, spinning head and nozzles diameters
were preliminary evaluated and adjusted to obtain the best
performance in rapport with each tested polymer solution.
Different geometries of the collecting supports may be
used for fiber deposition, regardless of the types of spinning
head and polymer solutions involved, as can be seen from
the examples illustrated in Figure 3.
An important factor for the successful rotational spinning
of any synthetic or natural polymer consists in the preparation
of solutions with adequate concentrations, rheological properties
and stability. We have previously found that a mixture of
formic and acetic acid in 4:1 volumetric ratio enhances the
gelatin solvability, lowers the viscosity, and provides a good
stability and homogeneity of the resulting solutions [21].