Proceedings of the Public Security S&T Summer Symposium 2009

CRTI 07-0121RD

Lightweight Composite Armour for Improvised Explosive Devices Protection: A Single-Walled Carbon Nanotube Solution

Project Lead: National Research Council Canada – Steacie Institute for Molecular Sciences

Federal Partners: National Research Council Canada – Institute for Aerospace Research and Institute for Microstructural Sciences, Royal Canadian Mounted Police

Industry Partner: Allen-Vanguard Corporation

Other Partners: University of British Columbia, McGill University

Objectives

The objective of this three-year project is to mitigate explosion and ballistic hazards for first responders with armour of significantly reduced weight. The project targets a reduction of 25 percent in the weight of affected protective armour components. The objective will be achieved by improving the architecture of materials currently used and by developing lighter and higher performance materials, all based on the use of single-walled carbon nanotubes (SWCNT), the strongest material known.

The project is divided into five work packages (WP) with a feedback mechanism that allows material, process, and properties improvements: WP1, “SWCNT Production and Quality Certification”; WP2, “Integration and Fabrication”; WP3, “Testing and Modelling”; WP4, “Manufacturing of Parts and Insertion into Suit”; and WP5, “Field Testing.”

Relevance

The project addresses “responder requirements” under the CRTI’s investment priority of “Explosive – Threat and Capabilities.” Currently available personal protective equipment for explosive ordnance disposal (EOD) protects against improvised explosive devices (IEDs), but its weight makes it impractical for some situations, especially those requiring swift or long actions, or those involving extreme conditions. As multidimensional threats arise, such as the combination of an IED with a CBRN agent, controlling the weight of the armour becomes even more critical.

Recent Progress and Results

Since the project began in September 2008, the focus has been on literature reviews for WP1 and WP2, screening models and readying equipment for WP3, and beginning fabrication for WP4. The SWCNT production facility at the National Research Council has been commissioned, the instrument has been calibrated, and the production of SWCNT is now being carried out routinely. Technicians are improving the yield of the production equipment to limit post-processing, with a target yield of 80 percent.

The bulk of the work has been on WP2 to produce samples to activate WP3 and WP4. Four of the five activities for WP2 have been initiated: (1) A two-step protocol to integrate SWCNT into polyacrylics has been successfully developed and samples have been fabricated and sent for testing. Several approaches to integrate SWCNT into polycarbonates are currently being examined. (2) The chemistry to anchor SWCNT to vinyl ester resins has been developed successfully. (3) A method to fabricate lyotropic liquid crystal from SWCNT has been developed and the dope has been used to fabricate pristine SWCNT fibres. Raman spectroscopy has been used to characterize the alignment. In addition, pristine carbon nanotube (CNT) fibres have been fabricated by coagulation spinning. Mechanical testing on these fibres is currently underway. (4) A process to make SWCNT-polyacrylonitrile fibres using electrospinning has been developed successfully. Mechanical testing is currently underway. (5) Various forms of “buckytube” papers have been made and mechanical testing has been performed. In addition, two impregnation techniques have been tested and assessed.

In WP3, researchers have screened modelling algorithms for penetration and perforation, and studied penetration and perforation mechanics for armour designs. In addition, they have used a fibre architecture-based computational model to assist in the design and selection of the CNT-matrix material combination and the geometric orientation of the fibrils. In WP4, hybrid systems of CNT with Kevlar at the fibril and yarn level have been demonstrated with encouraging preliminary results.

Impact

Successful incorporation of SWCNT within the focus areas of protective materials can either significantly reduce weight over several armour component areas or, for the same weight, add protection where no protection currently exists. All military, law enforcement, and first responder personnel wear various levels of body armour, whether for EOD or other high-threat environments. This project will provide the first benefits of material enhanced through nanotechnology to this large group of critical personnel. There is the potential to have various levels of capability or property enhancements, or weight reductions using SWCNTs, depending on the type of protective material technology, ranging from visors, helmet shells, rigid armour plates, high-density polyethylene composites to soft armour. Breakthroughs in one or several of these areas can have wide-reaching implications for armour multi-functionality.

Author

Benoit Simard, National Research Council Canada, benoit.simard@nrc-cnrc.gc.ca

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