بررسي خواص ريزساختاري نانوالياف موازي پلي آكريلونيتريل جمع آوري شده با استفاده از جريان هواي گرم در روش الكتروريسي

Microstructural Characterization of Aligned PAN Nanofibers Collected by Hot Air Flow in Electrospinning Method

A modified technique is designed to prepare aligned nanofibers to chal¬lenge the existing limitations in collecting methods of nanofibers such as, thickness of collected layer, alignment and productivity of nanofibers. Collecting and simultaneously heating of the aligned nanofibers were carried out by using a rotating drum fixed on top of syringe needles and applying hot air flow. This electrospinning set up can facilitate heating of the nanofiber in electrospinning zone (distance between two syringe needles). Polyacrylonitrile (PAN) nanofibers were electrospun from its 14 wt% solu¬tion in dimethylformamide (DMF) under practical conditions. The above method resulted in low rupture rates and increased maximum take up speed for two collections. The obtained results from angular power spectrum analy¬sis showed better fiber alignment with increasing take up speed, although SEM studies demonstrated wider diameters of nanofibers being produced by the modified method. The glass transition temperature (Tg) of all the pre¬pared samples were between 70°C and 90°C. The recorded spectra from FTIR were close to common PAN fibers with peaks at 2240 cm"1 (CN stretch), 2920 cm"1 (CH2 bend), 1450 cm"1 (CH stretch) and 1730 cm"1 (CO stretch) wavenumbers. The diffraction patterns obtained from WAXD technique show also an equatorial peak in 20 = 17° for PAN nanofibers. Our quantita¬tive analysis of WAXD and FTIR diagrams have revealed positive effects by the modified method on crystallization degree of nanofibers produced at higher take up speeds.