Electrospinning of polyamides with different chain compositions for filtration application

Abstract

Electrospinning of several polyamides, PA6, PA66, PA612, PA614, PA1012, and PA1014, having different chain compositions and lengths of diacid and diamine segments, was demonstrated. Electrospinnability and fiber production rate of these polyamides were evaluated. Electrospun fibers were characterized with regard to their use in air filtration by measuring fiber diameter and filtration efficiency of fiber coating. Longer nonpolar chain segments of higher polyamides could in theory indicate higher dielectricity compared to PA6 and PA66, which would be an advantage in filtration applications. The solubility in polar formic acid and electrospinnability of higher polyamides, on the other hand, were clearly impaired with increased length of chain segments. Hence, PA66 is our best choice, and PA612 and PA6 our second options for commercial filtration applications if fiber electrospinnability, production rate, fiber diameter, and its distribution are concerned. Filtration efficiency of more than 95% of the particles having a diameter of 0.16 lm and above was achieved with 0.5 g/m 2 coating of PA66 nanofibers. Further increase in coating weight mainly increased the pressure drop to an unusable range without a significant further improvement of filtration efficiency.Like reviewed earlier some simple polyamides, such as PA6 and PA12, and some copolyamides such as PA66 and PA46 are verifiably applicable in electrospinning. Still, we can suppose that the structure of the polyamide FIG. 2. Electrospun PA66 fibers produced from solution having concentrations of (a) 6%, (b) 9%, (c) 12%, and (d) 15%. FIG. 4. Fiber diameters with standard deviation and fiber production rates of different polyamides. FIG. 5. X-ray diffraction spectrums of (a) newly electrospun PA6 sample and (b) after 2 months ageing.

Electrospinning of polymer nanofibers: Effects on oriented morphology, structures and tensile properties

“…Electrospun fibers with micron-sized diameters have found extensive functions in filtration applications [23,[96][97][98]. Electrospun non-woven fabrics used for filtration provide the advantages of high surface area to volume ratio, low air resistance, lower filter mass and flexibility of adding surface functionality on the fibers by blending or incorporating nanofillers [97].…”

Dual-functional OPH-immobilized polyamide nanofibrous membrane for effective organophosphorus toxic agents protection

“…Therefore, nanofibers possessed unique superiority in air permeability, particle filtration and adsorption, automatically becoming the appropriate choice for preparing protective masks and clothing. Regarding nanofibers with a pore size of around 100 nm, the filtration efficiency for particles with a 200 nm diameter reached over 95% [19,20]. On the above basis, other properties of nanofibers, such as more easily modified surface functionalities and a membrane-like appearance were suitable for enzyme immobilization and reusability [21][22][23][24][25][26][27].…”

Electrospun Nanofibers for Air Filtration

“…PA nanofibers can be easily fabricated in a controlled manner, and these nanofibrous membranes exhibit many interesting morphological characteristics, such as high surface area to volume ratio, high porosity, and vast possibilities for surface functionalization. These advantages make PA electrospun membranes good candidates for air filtration media [27][28][29]. Gibson et al [30] first demonstrated the fabrication of PA-66 filtration membranes and revealed that electrospun nanofiber membranes were extremely efficient at trapping airborne particles (0.5-200 m).…”