A Study of Electrospinning and Characterization of Poly (Ɛ-caprolactone) Nanofibers
Nanofibers of poly (Ɛ-caprolactone) (PCL) were produced by electrospinning a 10 wt% solution of PCL/Chloroform and ethanol at room temperature. For electrospinning the voltage was varied from 15-30 kV in seven regular intervals while keeping the feed rate (0.5 ml/h) and needle tip to collector distance (25 cm) constant at ambient atmospheric conditions (22 ± 2˚C and 40% R.H). This led to the study that how voltage variations effect the final morphology and diameter of nanofibers. SEM micrographs of the samples elaborated their morphology as heterogeneous and homogeneous mixing of nanofibers and their diameters ranging from 90-200 nm. Moreover, the crystallinity ratio (C.R) and thermal behavior of pure PCL and its electrospun nanofibers were studied using Differential Scanning Calorimeter (DSC). Results showed that the Tg of pure PCL and of nanofibers was same as -63.8˚C and the crystallinity ratio of pure PCL was 40% that increased to 50% after electrospinning. A viscosity analysis was done for different solvents of PCL taking 10 wt% PCL for each. Chloroform, THF, acetone, o-xylene and a combination of chloroform with ethanol that showed chloroform with the highest viscosity as 3645 mPa.s and o-xylene with the lowest as 331 mPa.s. The rheological study of these solvents helped in determining the appropriate solvent for PCL electrospinning. So, a combination of chloroform and ethanol was selected as the best choice as it has the optimum viscosity of 425 mPa.s with 10 wt% PCL allowing having higher concentrations of PCL with good solubility for electrospinning.