No abstract

Basalt fiber was first treated in a mixture of formic acid (FA) and dichloromethane (DCM) to reduce its diameter down to one micrometer. Electrospinning process was utilized to produce treated basalt fiber (TBF)-reinforced nylon 6,6/epoxy (NY/EP) hybrid nanofibril composites. NY/EP polymers have been dissolved in 80:20 mixture of FA/DCM solvent to form a homogenous solution. TBFs with different weight ratios of 5, 10, 15, 20, and 25 wt% were added to NY/EP (ratio of 5:1). The morphology of the hybrid nanocomposites was investigated by scanning electron microscopy and their compositions were analyzed using energy-dispersive X-ray spectroscopy. The thermal properties were studied by differential scanning calorimetry and thermogravimetric analysis. The mechanical properties of the hybrid nanocomposites, including tensile strength and modulus, are improved with respect to NY/EP hybrid nanofibers. An increase of 76% and 87% in tensile strength and Young’s modulus was acquired, respectively, at 15 wt% of TBF. Also, the addition of TBF increased the thermal stability of nanofibril composites.

This study is an attempt to optimize the electrospinning process to produce minimum Nylon 6,6 nanofibers by using Taguchi statistical technique. Nylon 6,6 solutions were prepared in a mixture of formic acid (FA) and Dichloromethane (DCM). Design of experiment by using Taguchi statistical technique was applied to determine the most important processing parameters influence on average fiber diameter of Nylon 6,6 nanofiber produced by electrospinning process. The effects of solvent/nylon and FA/DCM ratio on average fiber diameter were investigated. Optimal electrospinning conditions were determined by using the signal-to-noise (S/N) ratio that was calculated from the electrospun Nylon 6,6 nanofibers diameters according to “the-smaller-the-better” approach. The optimum Nylon 6,6 concentration (NY%) and FA/DCM ratio were determined. The morphology of electrospun nanofibers is significantly altered by FA/DCM solvent ratio as well as Nylon 6,6 concentration. The smallest diameter and the narrowest diameter distribution of Nylon 6,6 nanofibers ([Formula: see text][Formula: see text]nm) were obtained for 10 wt% Nylon 6,6 solution in 80 wt% FA and 20 wt% DCM. An increase of 118%, 280% and 26% in tensile strength, modulus of elasticity and elongation at break over as-cast was obtained, respectively. Glass transition temperature of Nylon 6,6 nanofibers were determined by using differential scanning calorimeter (DSC). Analysis of variance ANOVA shows that NY% is the most influential parameter.

The present work is an attempt to model the diameter of Poly Lactic-co-Glycolic Acid (PLGA) nanofibers by utilizing response surface methodology (RSM) and artificial neural networks (ANNs). Hence, determining the optimal electrospinning process conditions to produce a minimum fiber diameter. For modelling the average diameter of nanofibers, RSM approach based on four parameters (polymer concentration, high voltage and needle tip to collector distance and spinning angle) with five-level was compared to ANN technique. In the RSM approach, central composite design (CCD) was used to determine the individual and interaction impacts of the parameters on the average diameter of nanofibers. Several ANNs of single and double hidden layers with different number of cells for each were tried to obtain the best network structure. The experimental and predicted PLGA fiber diameters using an ANN showed a strong correlation, indicating that the network topology of 4-14-1 has good predictability for analyzing factors impacting PLGA fiber diameter. The average absolute relative error for predicting PLGA nanofibers’ diameter using ANN (2.24%) is slightly less than that obtained from RSM (2.59%). The high regression coefficient between the variables and the response (R2 = 0.9636) shows a good second-order polynomial regression model for evaluating experimental data. The R2 value was 0.945, indicating that the ANN model was good fitting with the experimental results. The optimum combinations (PLGA concentration of 26 wt.%, high voltage 22 kV, needle tip to collector distance 20 cm, and spinning angle 60o) were developed by RSM model for electrospinning PLGA nanofiber that can produce fine, consistent, and high-quality nanofibers.

The present study is an attempt to fabricate composite nanofiber mats from polystyrene (PS) loaded with exfoliated graphite nanosheets (EGNS) by using electrospinning technique. EGNS with different weight ratios of 3, 6, and 9 wt.% were added to PS (20 wt.%). The fiber diameter and morphology of the composite nanofiber mats were investigated by scanning electron microscopy (SEM). Results revealed that as EGNS concentration was increased, the average diameter of EGNS/PS electrospun nanofibers decreased. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to investigate the thermal properties. The tensile strengths and Young’s modulus of the composites improve with the increasing EGNS concentrations compared to PS nanofiber, which indicates 84% and 88% augmentation, respectively at 6 wt.% of EGNS. Also, the addition of EGNS increased thermal stability of composite nanofiber mats.