Rapid consolidation and curing of thermoset composite parts using specialized elastomeric tooling for resin infusion (SETRI)

Abstract

Two composite material systems were evaluated: industry standard woven carbon fiber reinforcement with low viscosity infusion epoxy matrix and woven cellulose fiber with a high bio-content, recyclable epoxy resin matrix. Carbon fiber epoxy materials were first used to demonstrate the infusion expansion of set, testing multiple process parameters such as consolidation pressure, curing temperature, and curing time. Then once the process was established and successful, was expanded to the bio-based recyclable materials. As expected, parts made using this high pressure process were thinner, showed slight increases in stiffness and strength, and had less surface and internal voids as consolidation pressure was increased. Curing temperature and time has no significant effect on part quality. This expanded SET process was further characterized through a full factorial set of experiments with replicates and quality metrics measured such as stiffness, strength, surface roughness, microscopy, and composite volume fractions. Following consolidation and curing, the recyclability of the cellulose textile is assessed by dissolving the commercially available bioresin in a dilute acetic acid bath to reclaim the textile and create a recyclable thermoplastic. Future work includes demonstration for complex 3D shapes with laminate and sandwich construction, CFD modelling of the infusion process, recycling and testing of different natural fiber materials (e.g., jute, flax), recycling of the dissolved thermoplastic resin for future use and reuse of the recycled textiles in other biocomposite components, and a study on commercialization of the manufacturing tooling and process.

The capabilities of Specialized Elastomeric Tooling (SET), a low-cost and low-energy autoclave alternative for consolidating and curing thermoset and thermoplastic composite parts made of ‘prepreg’ material, are expanded to allow vacuum infusion of dry fiber preforms through a demonstration project. In this case, SET tooling was designed to allow vacuum infusion of flat five-to-ten-ply, woven fiber preform with epoxy resin, consolidate under uniform pressure in a press, and thermally cured while still under load.