Development and characterisation of Polylactic acid / Bambara groundnut (Vigna subterranea (L.) Verdc) shells biocomposite for food packaging application

The major contributor of plastic pollution is the food packaging sector and efforts to replace the traditional plastic packaging with eco-friendly biocomposites can be a viable solution. Polylactic acid (PLA) is a biopolymer with potential in this regard but it has inherent challenges that could be countered by several methods including composite manufacture. In this work, biocomposites from PLA and Bambara groundnut shells (BGS) were successfully prepared by solution cast method with varying weight percentages (1 – 25 wt%) of BGS filler. Samples of the control (PLA) and the biocomposites were then characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), tensile testing, and thermogravimetric analysis (TGA) to investigate the structural, morphological, mechanical and thermal properties. The specimens were further probed for water absorption (WA), water vapour permeability (WVP), wettability, food contact migration (FCM), and soil burial biodegradability (SBD) properties. The results showed that the biocomposites successfully produced, achieved highest tensile property of 34.9 MPa with 5 wt% BGS loading, which was a 16.1 % increase when compared with the control. Wettability, WA, WVP and SBD of the PLA/BGS biocomposites were generally amplified with increase in BGS filler content. FCM analysis showed that most of the biocomposites did not exceed the overall migration limit (10 mg/dm2) and thus were acceptable for use as food packaging materials. Analysis of variance (p < 0.05) showed that the biocomposite properties with different filler loading had significant enhancements. The PLA/BGS biocomposites showed promise in application as sustainable green food packaging materials.