(734i) Graphitization Control in Carbon-Carbon Composites By Graphene Addition

Carbon-carbon composites, originally developed for aerospace applications, are materials that consist of a carbonaceous matrix with an embedded carbon filler providing the required reinforcement for thermal and mechanical stability. An important aspect of composites is the interdependence of the matrix and additive phases to strengthen one another and the material as a whole with the interfacial stress transfer being key to this reinforcement. The bonding between the matrix and the additive is crucial in understanding its behavior at the macro-scale. Understanding the material’s nanostructure to shed light on its interfacial dynamics is an unexplored aspect owing to experimental and probing challenges.

This work characterizes a carbon-carbon composites from the nano- to the micron-scale with a variety of analytical techniques. Both graphitizing and non-graphitizing matrices are evaluated with three variations of graphene: 300-800 nm reduced graphene oxide, 1-2 um graphene nano-platelets and 2-5 µm graphene. The carbon-carbon composite so formed is then characterized at different length scales to understand the graphene additives’ influence on the composites’ observable macroscopic properties. The interaction is also addressed using polarized light microscopy [1] and scanning and transmission electron microscopy [2].

Carbon-carbon (C-C) composites are a unique class of materials consisting of a carbon filler within a carbon matrix [3,4]. This carbon matrix is typically formed after carbonization and graphitization of a carbon precursor material [5,6]. Fibers made from carbon precursors such as polyacrylonitrile (PAN), rayon or pitch are typically used as the filler weaved in varied directions to get desired properties within a resin or pitch-based matrix formed from a liquid precursor or by impregnation within a matrix formed from a gas precursor [3,7]. These are also referred to as carbon-fiber reinforced carbon composites [8,9]. Carbon-carbon composites have found application in the aerospace industry as aircraft disc brakes and rocket re-entry nose cones, for instance, because of their superior tensile strength, electrical conductivity, and integrity at high temperatures [7,8].

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