Carbon Materials Research
The Carbon Materials Group at the University of Kentucky Center for Applied Energy Research (UK CAER) focuses on several areas of research, including: solution spinning of experimental fibers, conversion of precursor to carbon fiber, carbon fiber reinforced polymer composites, synthesis and applications of carbon nanotubes, polymer processing, and industrial and activated carbons. Further, this is complimented with a host of materials characterization capabilities. The group features an array of talented engineers, scientists, and researchers with combined decades of experience. In addition, a main focus of the group is the training of undergraduate and graduate students through hands-on research in these focus areas.
The University of Kentucky Center for Applied Energy Research operates one of the country's only production lines for spinning experimental fibers and precursor carbon fiber. The system is designed for researching the numerous parameters that are involved in fiber production. The carbon materials group is uniquely positioned to partner with industry on the development of new fibers and new carbon fiber products.
Development of experimental carbon fiber requires bench scale spin line characteristics mirroring that of mass production. At UKY CAER, advancements in continuous multifilament spinning for the production PAN-based precursor fiber are investigated; in particular, spin dope characteristics, die geometry, filtration, coagulation, washing, stretch, process oil and drying. Our spinline allows for experimentation with sparing quantities of innovative spin dopes for the production of experimental precursor tow, at minimal cost.
The Carbon Materials Group (CMG) is directly involved with the design, layup and fabrication of carbon fiber composite materials. Much of our most recent research and development in this space has focused on improving the through-thickness (z-direction) and in-plane thermal conductivity of filament-wound and hand-laid carbon fiber composites. Typical thermal analyses of the carbon fiber composites consist of laser flash analysis (LFA) - (Netzsch LFA 427 testing capabilities) for thermal diffusivity and infrared camera imaging of heat as it spreads through the composite. The CMG houses a small (~6" I.D.) autoclave for composite curing, as well as standard composite fabrication tools and accessories.
The Carbon Materials Group has been involved with multiwalled carbon nanotube synthesis and research since the mid 1990s. During that time, the carbon materials group researched many of the desirable properties that MWCNTs exhibit, including strength, stiffness, electrical conductivity, and thermal conductivity. Additionally, the group has worked extensively to make multiwall carbon nanotubes more accessible by driving down their cost through continuous production technology.
UK CAER holds two patents (US 7160531 and US 7504078) for the continuous synthesis of high quality (8 wt%) residual catalyst), aligned MWCNTs. The MWCNTs are CVD grown in a "wheat-field" orientation on a substrate, from which they are harvested either as a free-standing array or as a powder. UK CAER has a production capacity of approximately 1 kg of MWCNT powder per business day. UK CAER has, on-site, a high-temperature graphitization furnace capable of temperatures up to 2700° C with CNT sample sizes of up to approximately 25 g. The heat treatment of the MWCNTs yields a more graphitic microstructure and removes the residual iron catalyst.
At UK CAER, the carbon materials group has investigated the role of MWCNTs dispersed in thermoplastic and thermosetting polymers extensively. Our research has covered a broad spectrum of composite materials applications. The group has also investigated several applications for free standing arrays of MWCNTs, including thermal interface materials.
Polymer processing has been a main focus of the Carbon Materials Group since the late 1990s. Working with both thermosets and thermoplastics, research in this area has centered about mixing fillers into the polymers for improved mechanical and/or electrical properties. The CMG takes advantage of several pieces of equipment that are central to polymer mixing, including a Haake PolyLab system with 2 mixing bowl attachments and a twin-screw extruder (all capable of processing at ~400°C), a high shear Silverson mixer and Thinky planetary mixer. The group also has access to an Exakt 80E 3-roll mill.
The Carbon Materials Group also develops technologies for producing coal-derived feedstocks for the production of a range of high value carbon materials and specialty chemicals.
The program has successfully demonstrated that a broad range of value-added carbon materials such as carbon fibers, activated carbon fibers, cokes, binder pitches, and carbon/carbon composites can be produced from coal utilizing mild, non-hydrogenative solvent extraction.