A comprehensive study on aloe vera, graphene oxide, and graphene nanoplatelet modified PVA-based composite films by comparison with hydrogel form: mechanical, thermal, and self-healing properties

Abstract

Self-healing polymer composites have garnered mounting interest due to their capacity to prolong the service life of products. Consequently, the present study investigated the performance of polyvinyl alcohol (PVA)-based self-healing composite films comprising graphene oxide (GO), graphene nanoplatelets (GNPs), and aloe vera powder (AV). Composite films containing 0.012 g GO, 0.012 g GNPs, and 2 wt% aloe vera powder (PAGGN); 0.024 g GNPs and 2 wt% aloe vera powder (PAGN2); and 0.012 g GO and 3 wt% aloe vera powder (PAG1) were determined to be optimal. Their hardness values were 238.38, 209.00, and 502.71 MPa, respectively, and their elastic modulus were 2.54, 2.41, and 3.76 GPa, respectively. The PAG1 composite film had a hardness value and elastic modulus approximately 22- and 19-times higher than those of the composite film containing only aloe vera (PA), respectively Crucially, the optimal composite films had self-healing rates of 99.5% (PAGGN), 89.02% (PAGN2), and 51.00% (PAG1). Notably, hydrogen bonds formed between the hydroxyl groups of PVA and the oxygen-containing functional groups on the surfaces of aloe vera and GO appear to play a fundamental role in improving the mechanical strength and self-healing performance of the composite films. Consequently, Fourier transform infrared and nuclear magnetic resonance spectroscopy confirmed the presence of these bonds, which significantly support the structural integrity and healing ability of the composite films. Therefore, this study has developed sustainable, durable, and functional PVA-based composite films with high mechanical properties and self-healing rates.