PhD Thesis Colloquium: : Mr. Samir Mandal (27/05/25)
Thesis title:
Improving Mechanical Properties and Self-Healing by Dynamic Bonds at Interface in Carbon Fiber Reinforced Epoxy Laminate and its Recycling
Faculty advisor(s):
Prof. Suryasarathi Bose (Co-Supervisor - Prof. Subodh Kumar)
When?
27th May, 2025 (Tuesday), 3:00 PM (India Standard Time)
Where
KPA Auditorium, Dept of Materials Engineering
Abstract:
Carbon fiber-reinforced epoxy (CFRE) laminates, vital for aerospace applications due to their exceptional properties, face limitations in interfacial bonding, electrical conductivity, damage tolerance, and recyclability. This Ph.D. research introduces a comprehensive strategy to overcome these challenges by focusing on interfacial engineering with dynamic bonds, imparting multifunctionality through tailored nanomaterials, and enabling a novel green recycling pathway. Initially, polyetherimide (PEI)-based sizing agents, including a dynamic disulfide bond-functionalized variant (BA), were developed, leading to significant enhancements in flexural strength (FS) and interlaminar shear strength (ILSS), with BA-CFRE0.25 exhibiting 51% self-healing (SH) efficiency while maintaining electromagnetic interference (EMI) shielding, Joule heating, and de-icing capabilities. Further improvements were realized by incorporating graphene oxide (GO) with BA (BAGO), boosting FS and ILSS by up to 40% and 35%, respectively. The introduction of covalent adaptable network (CAN)- functionalized GO (hGO) within the epoxy matrix yielded 38% and 37% increases in FS and ILSS, and a 57% SH efficiency. The most substantial advancements were achieved through the synergistic combination of BAhGO on carbon fibers and hGO in the matrix, resulting in 44% and 41% improvements in FS and ILSS, and a peak SH efficiency of 61%, supported by density functional theory (DFT). Furthermore, these functionalized nanomaterials significantly enhanced EMI shielding (49 dB), Joule heating (186 ℃), and de-icing (41 s) performances. Addressing sustainability, a novel, eco-friendly recycling method using seawater and bio-based acids enabled full epoxy recovery and its successful reuse as a curing agent, demonstrating closed-loop recyclability. This research establishes a new design paradigm for advanced aerospace composites by integrating interfacial engineering, multifunctional nanomaterials, and green recycling methodologies.