Microstructural evolution and mechanics of hot-drawn CNT-reinforced polymeric nanofibers

作者：Cai, Jizhe; Chawla, Sneha; Naraghi, Mohammad^*

来源：Carbon, 2016, 109: 813-822.

DOI：10.1016/j.carbon.2016.08.080

• WALL CARBON NANOTUBES
• ELECTROSPUN POLYACRYLONITRILE NANOFIBERS
• COMPOSITE FIBERS
• CRYSTALLIZATION
• NANOCOMPOSITES
• CONDUCTIVITY
• STRENGTH
• BEHAVIOR

To unravel reinforcing effect of CNTs in polymeric nanofibers, polyacrylonitrile (PAN)/SWNTs nanofibers with various CNTs content (0.1-0.5 wt%) were electrospun. Nanofibers were hot-drawn to enhance PAN chains and SWNT alignment. The microstructure of composite nanofibers was studied via polarized Raman and IR spectroscopy, x-ray diffraction, and TEM imaging. The study pointed to a marked contribution of SWNTs at low SWNT contents (0.1 wt%) to chain mobility and alignment during electrospinning. Evidence of volume changes was reported during hot-drawing, depending on CNT content, alluding to arrangement of CNTs in nanofibers. Indirect evidence of SWNT agglomeration, adversely affecting reinforcement efficiency at higher SWNT contents, was presented. Hot-drawing above T-g of PAN led to massive chain and SWNT alignment and orientation-induced crystallization. The most promising mechanical performance was achieved in hot-drawn ribbons with low SWNT content, where formation of an interphase-evidenced in TEM images - led to significant enhancement of effective reinforcement modulus of similar to 2.15 +/- 1.97 TPa, with the average value considerably higher than modulus of CNTs. This study demonstrates a clear path to prepare PAN nanofibers with high chain alignment as precursor for the next generation of carbon nanofibers with unprecedented strength and modulus.

• 出版日期2016-11