CNF Mat – Continuous Nanomaterial Reinforced Sheet Material for Use in Composite Systems
Applied Sciences, Inc. (ASI) has developed a new product form for carbon nanofibers called “CNF Mat”. CNF Mat is a continuous nanomaterial sheetgood produced using low-cost, commercially available materials. Key properties of CNF Mat are flexibility and durability that enable reel-to-reel processing methods such as pre-pregging, and porosity that enables effective infusion with resin.
When compared to other composite materials, CNF Mat provides opportunities to reduce composite weight while adding multi-functionality. ASI can customize the CNF Mat material to specific applications by tailoring the areal weight, thickness, and electrical conductivity through variation in the CNF fiber type, carrier veil or fabric, and use of binders.
Figure 1. Representation of the materials that are used to make CNF Mat.
Properties of CNF Mat
CNF Mat was originally developed for EMI shielding applications, but is also ideally suited to enhance composite mechanical properties such as interlaminar shear strength, tensile strength, and modulus. In addition, this emerging class of materials has demonstrated significant reduction in the vibration damping coefficient of composite systems.
Motivation for Development of CNF Mat
The development of a continuous mat or veil material that can replace some conventional composite mat materials with additional functionality is highly desirable. As this material can also be processed on the same production lines as the conventional composites that it replaces, it becomes even more desirable. In this case, the CNF Mat material incorporates high-quality, multi-functional nanomaterials into composite systems and can be processed using the same equipment or techniques as conventional composites. In addition, because this product form incorporates pre-dispersed CNF into the sheetgood, issues of dispersion typically associated with nanomaterials is eliminated.
Versatility of CNF Mat Materials
As noted, CNF Mat is produced from low-cost commercially available materials. Both woven fabrics and non-woven veils can be used as the backbone or substrate of CNF Mat and provides the material sufficient inherent strength for a wide variety of composite processing techniques. In addition, given the diversity in woven fabrics and non-woven veil materials available, ranging from polymer fiber to metal coated carbon fiber veils, numerous CNF mat compositions are possible, which in turn means there are a vast array of applications for these materials.
Figure 2. CNF Mat materials ready for processing into composite components.
Processing of CNF Mat Materials
Over the last year, ASI has established the ability to produce CNF Mat materials on conventional composites processing lines. Commercial prepreggers have successfully produced over 300 square feet of continuous CNF mat which was processed on two prepreg lines:
Renegade Materials in Springboro, Ohio and
Cytec Engineered Materials in Anaheim, California.
Figure 3. CNF Mat material being processed on a traditional prepreg line.
The CNF Mat materials processed at Renegade Materials’ industrial scale pre-preg line were processed using with no special handling, backing paper, or equipment required. ASI’s CNF Mat is the first continuous nanomaterial sheetgood to be processed on reel-to-reel equipment on an industrial scale without any special handling or processing considerations needed.
Figure 4. CNF mat processing on Cytec’s 13 inch pre-preg pilot line. Cytec successfully resin-impregnated over 100 linear feet of continuous CNF mat using typical operating conditions.
CNF Mat provides new degrees of freedom in using nanomaterials in composite systems. CNF Mat not only permits accurate placement of plies, it also eliminates dispersion concern issues associated with nanoparticle reinforced systems and is suited to processing using existing composite processing equipment. CNF Mat is also durable enough to be directly substituted for conventional materials, using traditional equipment to make prepregs.
Contact Patrick D. Lake to learn more about Nanomat.
Mr. Lake is a Chemical Engineer with experience in growth of VGCF and CNF, and fabrication of high thermal conductivity carbon-carbon composites. Patrick pioneered the development of ASI’s Nanomat under funding from the US Air Force. Patrick is currently working to refine the production process and develop new applications for the material.