Fabrication and properties of composites utilizing reclaimed woven carbon fiber by sub-critical and supercritical water recycling Chase C. Knight, Changchun Zeng * , Chuck Zhang 1 , Richard Liang High-Performance Materials Institute, Florida State University, Department of Industrial & Manufacturing Engineering, FAMU e FSU College of Engineering, Tallahassee, FL 32310, USA highlights  Sub-critical and supercritical water is highly efficient for composite recycling.  12-layer aerospace grade carbon fiber composites were recycled in woven form.  Multi-layer composites were fabricated using the recycled woven fiber.  Recycled-fiber composites maintained 80e95% of original flexural strength.  Reuse of the reclaimed matrix polymer is feasible with this recycling technology. article info Article history: Received 5 June 2014 Received in revised form 25 September 2014 Accepted 15 October 2014 Available online 28 October 2014 Keywords: Composite materials Multilayers Polymers Mechanical properties abstract Supercritical fluid recycling has emerged as an appealing method for recycling carbon fiber reinforced plastics (CFRP). Under supercritical conditions, the high reactivity, low viscosity and high diffusivity of water greatly facilitate the efficient degradation of the polymer matrix to allow the harvesting of clean and mostly undamaged fibers. We previously reported the successful use of supercritical water recycling to recover carbon fibers from high-performance single-layer composites and possibly multi-layered composites. The fibers are reclaimed in the original woven architecture, which is beneficial for direct use for reclaimed-fiber composites. In this study, the fabrication of reclaimed-fiber composites (RFC) was investigated using fibers recycled from aerospace-grade IM7/8552 (Hexcel) 12-layer composites. Two fabrication methods e hand lay-up and vacuum infusion e were attempted. The recycled matrix ma- terials were also combined with fresh resin and cured. The reclaimed-fiber composites exhibited 80e95% of flexural strength of virgin carbon fiber composites. This paper also discusses the manufacturing issues associated with the reuse of reclaimed materials. © 2014 Elsevier B.V. All rights reserved. 1. Introduction The carbon fiber market is forecast to grow at an annual rate of 17% over the next five years, reaching an estimated 118,600 tons (value of $7.3 billion) by 2017. Byextension, the carbon fiber rein- forced plastics (CFRP) market is predicted to grow at a rate of 16% annually from 2012 to 2020 [1]. The utilization of CFRP continues to increase rapidly in several industries. As such, there is an increased concern regarding the disposal of these materials at the end of their life cycle. As these waste disposal problems arise, increasing emphasis is being placed on the necessity to recycle CFRP. Landfill disposal is currently the main option for waste CFRP. However, the same superior properties of chemical and environ- mental resistance that make the CFRPs appealing for many appli- cations also make these materials nearly impossible to be broken down by natural means. To address environmental concerns and to possibly reclaim expensive CFRP materials, researchers are seeking to develop suitable CFRP recycling technologies [2]. For example, Adherent Technologies, Inc. (USA) developed a catalytic pyrolysis process that is capable of producing epoxy free carbon fibers with a tensile strength 83e99% of the virgin materials [3e6]. Researchers at the University of Nottingham [7e9] and Harbin Institute of Technology [10,11] have investigated supercritical fluid recycling of unidirectional composites. However, the recycling of higher-valued multi-layered, woven carbon fiber composites has not been reported. * Corresponding author. E-mail address: zeng@eng.fsu.edu (C. Zeng). 1 Current address: H. Milton Stewart School of Industrial & Systems Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA. Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys http://dx.doi.org/10.1016/j.matchemphys.2014.10.023 0254-0584/© 2014 Elsevier B.V. All rights reserved. Materials Chemistry and Physics 149-150 (2015) 317e323