In-Situ X-ray Deformation Study of Fluorinated Mulitwalled Carbon Nanotube and Fluorinated Ethylene-Propylene Nanocomposite Fibers
A fluorinated multiwalled carbon nanotube (FMWNT) was prepared by reaction of 3-perfluorooctylpropylamine with carboxylic acid groups on the oxidized carbon nanotube surface. The modification was confirmed by TGA, TEM, and solubility tests in a perfluorodecalin solvent. Nanocomposite fibers based on FMWNT and a fluoro-ethylene-propylene (FEP) copolymer were fabricated by melt blending and melt spinning. SEM examination indicated that the dispersion of FMWNT in FEP was significantly better than that of the as-received multiwalled carbon nanotube (MWNT) in FEP. Both yield strength and modulus of the melt-spun FMWNT/FEP nanocomposite fiber increased with increasing FMWNT content, but the elongation-to-break ratio decreased. In-situ small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques were used to follow the structural changes during tensile deformation of melt-spun fibers. In pure FEP fibers, perpendicularly arranged lamellar stacks (with respect to the fiber axis) became tilted at small strains, while destruction of lamellae took place at high strains (>250%), resulting in the rapid decrease of crystallinity. Surprisingly, the tilting of lamellar stacks was not observed in FEP/FMWNT nanocomposite fibers during deformation. We hypothesize that the well-dispersed FMWNT particles form a fibrous network, which can carry a significant fraction of local stress, resulting in overall increases of yield strength and modulus. A possible mechanism to explain the effect of FMWNT on the lamellar structural change in FEP and corresponding mechanical behavior is presented.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 914323
- Report Number(s):
- BNL-78891-2007-JA; TRN: US200809%%177
- Journal Information:
- Macromolecules, Vol. 39
- Country of Publication:
- United States
- Language:
- English
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