Self-Healable Interfaces with Improved Mechanical Properties Induced by Dynamic Network Reconfiguration in Carbon Fiber-Reinforced Epoxy Laminates

Mandal, S and Raj, R and Samanta, K and Kumar, S and Bose, S (2024) Self-Healable Interfaces with Improved Mechanical Properties Induced by Dynamic Network Reconfiguration in Carbon Fiber-Reinforced Epoxy Laminates. In: ACS Applied Materials and Interfaces .

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Abstract

Interfacial failure in carbon fiber-reinforced epoxy (CFRE) laminates is a prominent mode of failure, attracting significant research attention. The large surface-energy mismatch between carbon fiber (CF) and epoxy results in a weaker interface. This study presents a facile yet effective method for enhancing the interfacial adhesion between CF and epoxy with self-healable interfaces. Two variants of a designer sizing agent, poly(ether imide) (PEI), were synthesized, one without a self-healing property termed BO, and the second one by incorporating disulfide metathesis in one of its monomers that renders self-healing properties at the interface-mediated by network reconfiguration, termed BA. 0.25 wt of CF was found to be the optimum amount of BO and BA sizing agents. The surface free energy of CF drastically increased and became quite close to the surface energy of epoxy after the deposition of both sizing agents and the higher surface roughness. The improved surface wettability, presence of functional groups, and mechanical interlocking worked in tandem to strengthen the interface. The interlaminar shear strength (ILSS) and flexural strength (FS) of CFRE laminate sized with BO consequently increased by 35 and 22 and of CFRE laminate sized with BA increased by 26 and 19, respectively. Fractography analysis revealed outstanding bonding between epoxy and PEI-CF, indicating that matrix fracture is the predominant mode of failure. The self-healable interfaces due to the preinstalled disulfide metathesis in the sizing agent resulted in 51 self-healing efficiency in ILSS for BA-sized CFRE laminate. Interestingly, the functional properties, deicing, and EMI shielding effectiveness were not compromised by modification of the interface with this designer sizing agent. This study opens new avenues for interfacial modification to improve the mechanical properties while retaining the key functional properties of the laminates. © 2024 American Chemical Society.

Item Type:	Journal Article
Publication:	ACS Applied Materials and Interfaces
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society.
Keywords:	Bending strength; Fracture mechanics; Free energy; Interfacial energy; Reinforcement; Self-healing materials; Shear strength; Strain energy; Sulfur compounds, Carbon fiber reinforced; EMI; Epoxy; Epoxy laminates; Fibre-reinforced epoxy; Inter-laminar shear strengths; Joules heating; PEI sizing; Self-healing; Sizing agents, Surface roughness
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	01 Aug 2024 06:55
Last Modified:	01 Aug 2024 06:55
URI:	http://eprints.iisc.ac.in/id/eprint/85771

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