Session: 01-07: Multifunctional Composites

Paper Number: 111197

111197 - A Recyclable Self-Healing Composite With Advanced Sensing Property 

In recent years, polymer-based composites have replaced traditionally used ceramics and metals in a wide array of applications like automobiles, aerospace, construction, and medical devices. Often, these polymer composites are prone to various defects (e.g., matrix cracking, delamination, and contamination during the fabrication, among others) during their lifespan. In most instances, these defects are subsurface, thus challenging to detect and control. To address this issue, it is imperative to approach research in designing a polymeric composite that can not only quantify and detect damage but also possess self-healing capabilities on demand. Earlier investigations on material-based sensors have illustrated an enormous potency for self-sensing; however, the lack of in situ healing and (re)processability upon material failure remains a predominant challenge for self-sensing polymeric composites. Therefore, this study aims to develop a (re)processable, self-healing polymeric composite with self-sensing capabilities.

Vitrimers are an innovative polymeric material class comprising a covalently adaptive dynamic network stimulated by external factors, such as heat and UV light. Owing to the presence of dynamic exchangeable cross-link network, the vitrimer features thermoset-like mechanical and chemical resilience while still demonstrating flow on demand under external stimuli (e.g., heat) that are characteristic of thermoplastic-like materials. Herein, the vitrimeric polymer is engineered with piezoresistive carbon nanotubes (CNT) as a reinforcing element. While enhancing the mechanical resiliency, the CNTs create a percolation network within the composites enabling distributed self-sensing property while retaining self-healing capabilities offered by the vitrimeric matrix.

The composite was fabricated by using a solvent-free in situ polymerization of epoxy and anhydride-containing monomers with ~ 5 wt.% of CNTs. The presence of a labile dynamic network in the vitrimer enabled the topological rearrangement of the matrix upon thermal stimulation, thus imparting self-healing, malleability, and (re)processability to the bulk composite. Impressively, the vitrimer composite retained its strain-sensing properties on repeated re-shaping and re-processing cycles, indicating its potential application as a robust distributed strain sensor. Noteworthily, the key ingredients of the resulting composite (i.e., polyester-based vitrimer) can be comfortably recycled without using aggressive chemical treatment. This could enable the composite to be easily disposed of or recycled at the end of its service life and assist in reducing the subsequent manufacturing cost. The preliminary results revealed that the bulk composite possesses both self-sensing and in situ defect healing capabilities, thus offering a roadmap for the design of a resilient multifunctional composite with self-sensing and healing properties.  

Presenting Author: Sargun Singh Rohewal Oak Ridge National Lab and University of Tennessee

Presenting Author Biography: Sargun Singh Rohewal