Valorization of low-value cowpea lignocellulosic fibres to produce biodegradable plastics

The research investigates cowpea lignocellulosic fibres as a low-value biomaterial to produce biodegradable plastics for application in packaging and agriculture. Different products were produced, mainly cellulose fibres, and bio-composite materials (injection moulded, films and foams). The three research chapters focused on the different materials as outlined below:

1. The effect of extrusion as an alternative pre-treatment to conventional alkaline pre-treatment followed by bleaching on the production of cellulose fibres from cowpea lignocellulosic fibres was investigated. Different characterization techniques such as, FTIR, XRD, SEM and TGA were used to compare the quality of the cellulose fibres obtained by the two different methods.
2. In this section, we investigated cowpea lignocellulosic fibres as a filler in a PBSA/PHBV blend matrix, using already exising polymer processing techniques, such as extrusion, followed by injection moulding and extrusion film casting. Vaarious thermal (DSC, TGA and DMA), mechanical and barrier properties were used to evaliuate the effect of fibre addition on the properties of injection moulded bio-composite and bio-composite films. Moreover, to compare injection moulded bio-composites with the bio-composite films.
3. In this section, the effect of cowpea lignocellulosic fibres as a bio-based filler on the foam properties of PBSA was investigated. Different characterization techniques, such as thermal, thermomechanical, and morphological were used to evaluate the effect of cowpea fibres on foam properties of PBSA.

Overall, the different techniques employed demonstrated that low-value cowpea lignocellulosic fibres cab be used as a biomaterial to produce biodegradable packaging materials, such as cellulose fibres and bio-composites (injection moulded, films and foams). These developed materials can serve as alternative to petroleum-based and non-biodegradable plastics in some applications.