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Macroscopic Crosslinked Neat Carbon Nanotube Materials and CNT/Carbon Fiber Hybrid Composites: Supermolecular Structure and New Failure Mode Study
Final rept. 7 Jul 2011-30 Jun 2015
FLORIDA STATE UNIV TALLAHASSEE
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Two novel low-density material systems were explored to attempt to realize the ultimate intrinsic properties of CNTs for scale-up applications 1 continuous highly aligned CNT tapes or sheets and 2 CNT sheet carbon fiber hybrid composites CNTCF with aerospace-grade quality and carbon fiber concentration. We studied different approaches for engineering CNT networks in CNT thin films to achieve a high degree of alignment and graphitic crystal packing. We discovered that the unique geometrically constrained self-assembly and graphitic crystal packing of flattened and aligned CNTs can lead to close surface contact between CNTs to substantially improve the load transfer and mechanical properties. We also revealed that extremely low permeability X 10-17-19 m2 of CNT thin film or buckypaper materials could largely eliminate through-thickness flow of resin matrix during composite autoclave fabrication process. Modifications in the processing parameters and consideration of strong capillary resin absorption of CNT networks during CNT buckypaperCF prepreg materials for hybrid composites are needed to fabricate aerospace-grade hybrid composites with 5- wt. CNT and 50-60 vol. carbon fiber concentrations. The composites with CNTCF alternative interply hybridization demonstrated promising mechanicalelectrical multifunctional feature. Strong CNT layers acted as effective microcrack arresting layers to potentially improve damage tolerance properties.
APPROVED FOR PUBLIC RELEASE