A HOT-STRETCHED NANOFIBER SHEET OF POLYACRYLONITRILE/MULTI-WALLED CARBON NANOTUBE COMPOSITES

摘要

A hot-stretched nanofiber sheet of polyacrylonitrile (PAN)/multi-walled carbon nanotube (MWCNT) composites was prepared by electrospinning of suspension, which was composed of PAN terpolymer and MWCNT, and by stretching the sheet at elevated temperature along the rotating direction of the fiber collector to improve mechanical properties of carbon composites. MWCNT was acid-modified to increase hydroxyl groups on the surface and covalent grafted with PAN bound carboxylic acid before mixing to PAN. TEM observation was carried out to confirm the existence of MWCNT in the nanofiber sheet. SEM observations have shown a strong adhesion of MWCNT to PAN in the stretched sheet. Electrospun fiber diameters of PAN and PAN/MWCNT were ranged 100-400 nm and 100-300 nm, respectively. When the sheet was hot-stretched, the average diameter decreased to one-half of the PAN/MWCNT nanofiber, the tensile strength and the modulus of the sheet increased as much as 251% and 118%, respectively in comparison with those of PAN nanofiber sheet. This was attributed to the well orientation of the MWNT along the fiber axis and compact stack of the nanofiber in the sheet. Moreover, the elongation of the sheet was reduced from 15.5% to 7.7% showing a heat stable composite material.