Nanoporous Network-Enabled Out-of-Autoclave
Manufacturing of Fast-Cure Carbon Fiber Reinforced
Polymer Composite Laminates
Name
gonzalez-egonza-sm-aeroastro-2026-thesis.pdf
Size
76.08 MB
Format
Adobe PDF
Checksum (MD5)
099284969f8fda2fd07e55a7c47d34de
Author(s)
Gonzalez, Erick
Advisor(s)
Wardle, Brian L.
Date Issued
February 2026
Publisher
Massachusetts Institute of Technology
Abstract
Carbon fiber reinforced polymer (CFRP) composites are essential in aerospace due to their exceptional strength- and stiffness-to-weight ratios, making them ideal for structural components where weight savings and performance are critical. However, current manufacturing practices rely heavily on autoclaves to achieve the void-free, fully-cured composites required for demanding aerospace applications. While autoclave curing consistently produces high-quality laminates, it incurs significant capital and operational costs, consumes substantial energy, and can create production bottlenecks, especially for large and/or complex structures. These limitations have motivated growing interest in out-of-autoclave (OoA) manufacturing methods that aim to deliver comparable part quality without the associated autoclave costs and issues. This work explores the development of a novel OoA manufacturing process for a fast-cure thermoset epoxy autoclave CFRP prepreg system (Teijin IMS65/Q183)—which has a ∼1.5 hour cure cycle, compared to ∼4.5 hours for a typical aerospace epoxy CFRP prepreg system—using a nanoporous network (NPN) interlaminar film. The NPN, composed of electrospun polymer nanofibers, facilitates air evacuation and resin flow during cure through capillary pressure effects. These capillary forces replace the traditional autoclave pressure needed to achieve void-free laminates. Prior work has demonstrated that NPN-assisted vacuum-bag-only (VBO) curing can produce aerospace-grade composites using conventional (autoclave-required) epoxy CFRP prepreg systems. This thesis extends the process to fast-curing unidirectional (UD) and woven prepreg systems towards enabling significantly reduced cure cycle times while maintaining structural performance. Composite panels comprised of UD or woven prepreg plies were fabricated through an iterative experimental process that refined layup and curing procedures to minimize void content, targeting the aerospace industry standard of <1% void volume percent (vol%). Material characterization employed differential scanning calorimetry (DSC) and a visual resin wetting experiment to select processing parameters. The removal of residual volatiles from the NPN and/or prepreg by applying heat and vacuum prior to laminate assembly—a pretreatment process termed “desolventing”—was investigated as a potential process improvement. A parametric study examining debulking conditions (time and temperature), desolventing protocols, and an alternative NPN material revealed that desolventing prepreg reduced void content both with and without NPN present, and that debulking and desolventing are crticial steps to minimize void content. To further understand void evolution during cure, an in situ cure monitoring experiment was conducted using X-ray microcomputed tomography (µCT) imaging at incremental heating stages up to 80°C on a UD prepreg laminate. This study revealed that without NPN or prepreg desolventing, void growth occurred after initial evacuation via debulking, likely attributable to the release of volatiles during the heating steps. Conversely, desolventing both the prepreg and NPN successfully evacuated voids through the early stages of the cure cycle. Both unidirectional quasi-isotropic (UDQI) [0/90/±45]2S and woven [0]12 fiber architectures were investigated across two panel sizes: small panels (152.4 mm × 152.4 mm) for short beam shear (SBS) and three-point bending tests, and larger panels (152.4 mm × 279.4 mm) for Mode I and Mode II interlaminar fracture toughness testing. Final laminate quality was assessed using µCT. SBS, three-point bending, and Mode I/II testing results demonstrate that woven panels produced via the NPN-enabled VBO process have equivalent mechanical properties and characteristics to autoclave-cured baselines. SBS testing results for UDQI panels show that the autoclave-cured baselines perform 5.3% better than the VBO-cured specimens, indicating further work is required on the UD system. With the successful implementation of NPN into woven fast-cure CFRP laminates, this work demonstrates a viable VBO manufacturing route that achieves mechanical performance equivalent to autoclave-cured composites while significantly reducing capital costs and improving accessibility through standard oven-based processing. Future work includes extending these results to UDQI laminates through further process refinement, scaling the process to larger parts, introducing complex geometries such as L-shaped laminates, and integrating carbon nanotube heater films to enable localized, conductive heating for further reductions in cure time and energy consumption.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
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