Heterogeneously Structured Conductive Resin Matrix/Graphite Fiber Composites for High Thermally Conductive Structural Applications

ABSTRACT: The objective of this project is to design and fabricate tailored thermal interface and continuous paths among nanoscale conductive fillers and filler/graphite fiber to promote effective phonon transport along through-thickness direction. The goal is to realize at least 100 fold increase of Kz from 0.2 to 20+ W/mK in graphite fiber composites. Meanwhile, we will study to construct chemical or electronic bonding between the fillers and graphite fibers to ensure adequate or improved interfacial bonding to improve mechanical properties. Different from current homogeneous dispersion of conductive fillers in composites, we will study and demonstrate effective approaches to construct heterogeneously phonon transport paths in composites through fiber surface deposition and utilizing heterogeneously structured high thermal conductive resin matrix materials. This project will develop and demonstrate the following three unique techniques: Electrochemical deposition of high aspect ratio nanoscale silver flakes to increase fiber surface roughness for improving interface bonding and load transfer, and also create adequate thermal transport contacts between fibers and silver flakes; Utilize commercial available or modified heterogeneously structured conductive resin matrix to fabricate composites; Study and optimize phase separation behavior of heterogeneously structured conductive filler phase to create preferred continuous phonon transport paths along through-thickness directions for high thermal conductivity. Success of the proposed effort will lead to an affordable and scalable approach to make thermal conductivity (>20 W/mK) structural graphite fiber composites for potential Air Force and DoD applications. More importantly, these techniques and manufacturing processes are potentially easy to scale-up and low cost due to utilizing commercially available materials and route electrochemical deposition processes. BENEFIT: The effort will provide lightweight"thermal management"solutions that can have applications for airframe structures. Ceramic plates or stainless steel plates used in body armor add to their weight limiting the speed of the soldier under fire, and also lead to quick temperature build-up due to lacking of adequate heat dissipation capability. Specifically, these novel solutions can have a variety applications from lightweight body armor of the individual soldier with cooling capabilities to highly mobile tank and humvee applications as well as commercial vehicle applications. This effort can lead to improvements in"thermal management"capability for commercial aircraft usage to dissipate heat load of the limited aircraft idling time and the heating of the fuel by electronics by potentially eliminating metal heatsink devices and simplifying structure design and reduce overall structure weight. Effectively heating dissipation of aircraft onboard electronics also will lead to high system reliability. Thermal management plays a very vital role in the packing of high-performance electronic devices. Effective heat dissipation is crucial to enhance the performance and reliability of the packaged device.