TECHNOLOGY AREAS: Air Platform, Ground/Sea Vehicles, Materials/Processes

ACQUISITION PROGRAM: This program could support future UAV, USV and UUV programs in the future

OBJECTIVE: To develop a scientific understanding of the fundamental impediments to a well dispersed, ultrahigh carbon nanotube (CNT) loaded nanocomposite. To investigate new approaches to the purification, dispersion, functionalization and processing of carbon nanotubes (CNTs) that will lead to ultrahigh loading of CNTs for advance composites.

DESCRIPTION: Carbon Nanotubes (CNTs), despite their extraordinary mechanical properties, have shown only limited improvements to the mechanical properties of structural resins. The most interesting results have been obtained with very low concentration of carbon nanotubes, where relatively small improvements of some mechanical properties (example: 20% - 40% improvement on the interlaminar shear strength of glass vinyl ester composites) of structural composites have been reported. There is a lack of good scientific work in the area of high loading (larger than 5% weight ratio) of CNTs into structural resins. The main obstacle for this lack of scientific work with high CNTs loading ratios being the exponential growth of the viscosity of the mixture with CNT loading. Most dispersion methods are based on chemical functionalization followed by ultrasonic insonification but these methodologies appears to be limited to low weight ratios. New methodologies are required for the incorporation of high loading ratios of CNTs in structural resins. This STTR requests proposals that develop a clear scientific understanding of the main obstacles to ultrahigh CNT loading in nanocomposites and that proposes new methods or approaches to increasing the loading of well dispersed CNTs in structural resins beyond 10% weight fraction. It also requests that an understanding and characterization of the degree of dispersion and loading of the CNTs in the resin system and of the effects of these on the mechanical and physical properties of final nanocomposite materials be obtained.

PHASE I: During the Phase I research effort the PI will determine, quantify and model the fundamental impediments to well dispersed and highly loaded CNT composites. He will propose alternative methodologies for loading structural resins with CNTs and demonstrate the ability to disperse at least 10% weight fractions of single wall (SWNT), double wall (DWNT) or few wall carbon nanotubes (FWNT) (even though SWNTs, DWNTs and FWNTs are more expensive that MWNTs, it is anticipated that these will be easier to control and characterize than MWNTs due to their higher degree of crystallinity) into structural thermoset resins such as vinyl ester or epoxy and into structural thermoplastic resins such as PEEK. A very important part of this research effort is to develop and demonstrate a technique for the characterization of the degree of dispersion of the CNTs in the resins system. The PI will characterize the degree of loading and dispersion of the CNTs and correlate them with the mechanical performance of small nanocomposites coupons.

PHASE II: The PI will determine the maximum loading capability of well-dispersed CNTs that the new methodology offers. The PI will also demonstrate the capability of manufacturing large nanocomposite panels (4"x4"x1/64") and of the ability to machine them to appropriate geometries for mechanical characterization. The PI will manufacture nanocomposites with various CNTs loading ratios up to the maximum possible value and characterize their mechanical properties. The PI will determine the cost of the methodology in a per pound of nanocomposite basis and propose methods for lowering the cost. The PI will explore methodologies to expand the production capability.

PHASE III: This phase is not funded by the STTR program office. The PI will seek Navy program funding geared at demonstrating this technology in a larger scale. The proposer will transition technologies deemed beneficial, affordable, and sustainable (as a result of testing in Phase II) into a scalable demonstration.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: If the technology proves feasible and the potential for low cost manufacturing exists, it will have a large number of commercial applications such in the sports area, civil engineering, transportation, energy and others. Everywhere were composite currently apply, this technology could be a replacement with better performance.

REFERENCES:
1. Z. Wang, Z. Liang, B. Wang, C. Zhang and L. Kramer, "Processing and Property Investigation of Single-Walled Carbon Nanotube (SWNT) Buckypaper/Epoxy Resin Matrix Nanocomposites," Composite, Part A: Applied Science and Manufacturing, Vol. 35, No. 10, pp. 1225-1232, 2004

2. Frankland SJV, Caglar A, Brenner DW, Griebel M. "Molecular simulation of the influence of chemical cross-links on the shear strength of carbon nanotube-polymer interfaces". J Phys Chem B 2002;106:3046-3048.

3. Brenner DW, Shenderova OA, Areshkin DA, Schall JD, Frankland SJV. "Atomic modeling of carbon-based nanostructures as a tool for developing new materials and technologies." CMES 2002;3:643-673.

4. Krishnan A., Dujardin E., Ebbesen T.W.,"Young�s modulus of single�walled nanotubes", Phys. Rev. B.58, No20, (1998-II), 14013-14019

5. Yu M.,Files,B.S., Arepalli S., Ruoff R.S., "Tensile Loading of Ropes of Single Wall Carbon Nanotubes and their Mechanical Properties", Phys. Rev. Lett. 84, No 24, (2000) 5552-5555

KEYWORDS: Carbon Nanotubes; Dispersion; SWNT; nanocomposites; nanotechnology; composites

TPOC: Ignacio Perez
Phone: (703)696-0688
Fax: (703)696-0934
Email: [email protected]
2nd TPOC: Roger Crane
Phone: (301)227-5126
Fax: (301)227-5548
Email: [email protected]
3rd TPOC: Stan Ng
Phone: (301)757-2338
Fax: (301)342-8077
Email: [email protected]