PhD Thesis Colloquium: Mr. S. Parasuram (22/05/26)
Thesis title:
Interfacial Engineering of Carbon Fiber-Reinforced Epoxy Laminates via Vitrimer Networks and Hybrid Carbon Nanomaterials for Enhanced Mechanical Performance and Self-Healing
Faculty advisor(s):
Prof. Suryasarathi Bose and Prof. Subodh Kumar
When?
22nd May, 2026 (Friday), 3:00 PM (India Standard Time)
Where
KPA Auditorium, Department of Materials Engineering
Abstract
Carbon fiber-reinforced epoxy (CFRE) laminates are widely used in aerospace and automotive applications due to their high specific strength, stiffness, and durability. However, their broader adoption is often constrained by weak fiber–matrix interfacial interactions, limited damage tolerance, poor recyclability, and energy-intensive processing associated with long curing cycles. Addressing these challenges requires simultaneous improvement in interfacial bonding, incorporation of self-healing mechanisms, and development of rapid and scalable processing routes.
This work focuses on interfacial engineering of CFRE laminates using hybrid carbon nanomaterials and dynamic covalent adaptable network (CAN)-based vitrimer systems to enhance mechanical performance, self-healing capability, and processing efficiency. Initially, interfacial modification of carbon fibers was achieved using covalently coupled multiscale graphene oxide (GO)/carbon nanotube (CNT) nanoconstructs deposited via electrophoretic deposition (EPD). At an optimized nanofiller loading of 0.1 wt%, the modified laminates exhibited improvements of 30%, 24%, and 11% in interlaminar shear strength (ILSS), flexural strength (FS), and storage modulus, respectively. The hybrid GO/CNT architecture formed an interconnected hierarchical interphase resembling a “Velcro-type” structure, where GO sheets wrapped around the carbon fibers via π–π interactions, while CNTs provided mechanical interlocking with the epoxy matrix, resulting in enhanced load transfer.
To introduce self-healing functionality, a dual dynamic CAN-based vitrimer sizing was developed and applied onto the carbon fiber surface using a scalable spray-coating technique. The vitrimer-sized laminates exhibited enhancements of 23% in ILSS, 18% in FS, and 21% in storage modulus, along with a self-healing efficiency of 46% arising from disulfide bond exchange and transesterification reactions. To further enhance network adaptability and healing behavior, a triple dynamic CAN-based vitrimer matrix incorporating imine metathesis, transesterification, and acetal exchange reactions was developed. The vitrimer system exhibited a tensile strength of 78 MPa, while the corresponding carbon fiber-reinforced vitrimer epoxy (CFRVE) laminates demonstrated an ILSS of 51 MPa, FS of 664 MPa, and a self-healing efficiency of 54%. Chemical recyclability was demonstrated through selective dissolution of the vitrimer network, enabling recovery of carbon fibers, while Raman spectroscopy confirmed the retention of fiber integrity after recycling.
To address processing limitations, microwave-assisted curing was employed to significantly reduce crosslinking time. Under optimized microwave-curing conditions, the vitrimer system achieved complete curing within 20 min compared to 6 h under conventional thermal curing, corresponding to an 18-fold reduction in processing time. Relative to conventional epoxy systems cured for 10 h in hot-air ovens, the microwave-assisted process was nearly 30 times faster. Additionally, interfacial performance in vitrimer-based laminates was further improved using a hybrid GO/CNT strategy, where GO was first deposited onto carbon fibers using EPD, followed by rapid microwave-assisted CNT growth. The modified laminates exhibited an ILSS of 59 MPa, representing a 34% improvement over conventional CFRE due to enhanced interfacial adhesion and load transfer.
Overall, this work demonstrates a comprehensive strategy integrating interfacial engineering, dynamic vitrimer chemistry, and advanced processing techniques to develop high-performance, self-healing, recyclable, and rapidly manufacturable CFRE composites for next-generation aerospace and multifunctional structural applications.