Fabrication of Electrospun Polyamide-6/Chitosan Nanofibrous Membrane toward Anionic Dyes Removal

Nanofibrous filter media of polyamide-6/chitosan were fabricated by electrospinning onto a satin fabric substrate and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and water contact angle (WCA). Anionic dye removal capability of the filter was investigated for Solophenyl Red 3BL and Polar Yellow GN, respectively, as acidic and direct dyes were investigated with respect to solution parameters (pH and initial dye concentration) and membrane parameters (electrospinning time and chitosan ratio) through filtration system. Experiments were designed using response surface methodology (RSM) based on five-level central composite design (CCD) with four parameters to maximize removal efficiency of the filter media. Moreover, the effect of parameters and their likely interactions on dye removal were investigated by mathematically developed models. The optimum values for solution pH, initial dye concentration, electrospinning time, and chitosan ratio were predicted to be 5, 50 mg/L, 4 hr, 30% and 5, 100 mg/L, 4 hr, 10%, respectively, for achieving 96% and 95% removal of Solophenyl Red 3BL and Polar Yellow GN. Evaluation of the estimation capability of applied models revealed that the models have a good agreement with experimental values. This study demonstrated that polyamide-6/chitosan nanofibrous membrane has an enormous applicable potential in dye removal from aqueous solutions

The influence of process parameters on the properties of electrospun PLLA yarns studied by the response surface methodology

Poly (L-lactide) (PLLA) fibrous yarns were prepared by electrospinning of polymer solutions in 2,2,2-trifluoroethanol. Applying spinning from two oppositely charged needles the spontaneous formed triangle of fibers at a grounded substrate could be assembled into fibrous yarns using a device consisting of a take-up roller and twister. The effect of processing parameters on the morphology, diameter and mechanical properties of PLLA yarns was investigated by the response surface methodology (RSM). This method allowed evaluating a quantitative relationship between polymer concentration, voltage, take-up rate and distance between the needles' center and the take-up unit on the properties of the electrospun fibers and yarns. It was found that at increasing concentrations up to 9 wt % uniform fibers were obtained with increasing mean diameters. Conversely, the fiber diameter decreased slightly when the applied voltage was increased. The take-up rate had a significant influence on the yarn diameter, which increased as the take-up rate decreased. The tensile strength and modulus of the yarns were correlated with these variables and it was found that the polymer concentration had the largest influence on the mechanical properties of the yarns. By applying the RSM, it was possible to obtain a relationship between processing parameters which are important in the fabrication of electrospun yarns

Thermal properties of conductive nanocomposite core-shell filament yarns

380-386<span style="font-size:9.0pt;mso-fareast-font-family:SimSun;mso-bidi-font-family: " times="" new="" roman";mso-fareast-language:zh-cn;mso-bidi-language:th"="" lang="EN-GB">Thermal properties of conductive nanocomposite core-shell filament yarns have been investigated as a structure of a textile for the purpose of generating heat from an electrical power source. A fine copper monofilament is coated with a composite of polypropylene and various filler content of copper nanoparticles by an injection molding process to study the thermal properties of yarn as a function of filler shell content. Electrical analogy of Fourier’s law in thermal circuit has been used for development of a theory for thermal parameters. Then theoretical approaches are compared with modeling results obtained by ANSYS software and experimental results. Results reveal that although increase in filler content causes an increase in electrical and thermal conductivity of composite shell of yarn, heat generation in shell is negligible compared to that in core. Furthermore, results reveal that optimum value of filler fraction for desirable heat transfer is achieved at = 0.065. </span