Publications

Title Recycling Process for Carbon/Epoxy Composites
Source Proc. 46th Intl. SAMPE Symp. and Exhib.
Year 2001
Author(s) Allred, R. E.; Gosau, J. M.; Shoemaker, J. M.
Abstract The depolymerization of thermoset carbon fiber-reinforced epoxy matrix composites was studied to determine the significant reaction parameters and fiber quality produced by a catalytic reclamation process. This process was designed to recover valuable carbon fiber and an organic fraction from the depolymerization of carbon/epoxy composites. Design of experiments was used to determine significant process parameters including effects of temperature, time, catalyst concentration, heat transfer liquid to feedstock ratio, and agitation to estimate the purity of the carbon fiber produced from the reaction. Significant feedstock parameters that will affect the rate of reaction were the surface area available for reaction and the thickness of the composite. The carbon fibers reclaimed from the reaction reached 99.8% carbon values, i.e., 0.2% residual resin, which is sufficient to meet the market specifications for reuse in conductive molding compounds. The fiber tensile strength showed an 8.6% reduction after reclamation indicating that the process had little damaging effect on the fiber. Potential applications for the recycled fibers include thermoplastic and thermoset molding compounds and nonwoven sheet reinforcements. An economic analysis of a recycling business based on the catalytic depolymerization process showed that it should be profitable provided that adequate scrap composite feedstock can be obtained.
Keywords Recycling, composite scrap, catalytic depolymerization, carbon fiber composites, fiber tensile strength, thermoplastic, thermoset

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