The effect of the concentration of polyvinylbutyral solution on the process throughput and fibre properties was studied in needle and roller electrospinning. Whereas the polymer throughput is an optional independent parameter in needle electrospinning, it is a dependent parameter that is affected by both the material and process parameters in roller electrospinning. Polymer throughput increases considerably with an increasing concentration of polymer solutions in roller electrospinning. The properties of the nanofibers and the quality of the nanofiber layers were also studied. Fibre diameters increase with an increasing concentration in both techniques. Fibre diameters produced by needle electrospinning are smaller than those produced by roller electrospinning. The distribution of fibre diameters is rather narrow and not significantly dependent on the concentration of solutions in either technique.

In this study we aimed at finding different solvents for PVB and determine the effect of concentration and solvents on electrospun polyvinyl butyral (PVB) nanofibers. Firstly, we solved PVB in isopropanol, n-butanol, dimethylformamide, ethanol and acetic acid in various concentrations. Later, we compared fiber characteristics for each solvent. We observed that with increasing concentration, the fiber diameter increased. Bead formation occurred in low concentrations and low viscosity of polymer solution. Each solvent has a different effect on nanofiber morphology. It is observed that fiber diameter and morphology is one of the parameters that can be controlled by solvent.

The electric current was measured during needle-, rod- and roller electrospinning. The influence of the needle diameter, flow rate, protrusion needle length, and relative humidity on the current was studied using various polymer solutions. The results of Bhattacharjee et al. were confirmed in the experiments with polyethylene oxide solutions. Electrospinning from a droplet of a polymer solution placed on a steel rod confirmed the expected direct proportionality between the number of jets and the current. By measuring the current and the polymer throughput during roller electrospinning while simultaneously recording the process on a camera, the following process characteristics were found: the number of jets per spinning surface area, throughput per jet, total current, current per jet, and distance between Taylor cones on the surface of the spinning roller.

The electric currents between electrodes in the electrospinning process are based on the movement of charge carriers through the spinning space. The majority of the charge carriers are formed by ionization of the air close to the metallic needle and to the polymer jet. The salt contained in the polymer solution contributes to the concentration of charge carriers, depending on its amount. The conductivity of polymer jets does not significantly affect the current since the jets do not link the electrodes.

In this study, jet current and jet life in roller electrospinning of polyurethane (PU) were measured. The relationships between jet current and jet life and number of Taylor cones/m2 (NTC/m2), spinning performance (SP), and fiber properties (diameter, non-fibrous area) were analyzed. In addition, the effects of PU and tetraethylammonium bromide (TEAB) concentrations on jet current and jet life were determined. It was observed that jet current increases with PU and TEAB concentration, while jet life decreases. According to the results, NTC/m2 and spinning performance increase with jet current and decrease with jet life. Moreover, it was observed that jet current movement gives an idea about jet life, and it was also determined that there is a relationship between jet life and fiber morphology.