This thesis examines a hybrid composite obtained from integrating ocean-waste polypropylene (PP) with polylactic acid (PLA) and flax prepreg. The aim is to find a solution to ocean plastic pollution and to improve the mechanical and thermal properties of biocomposites. Using compression moulding, ocean waste 3D-printed PP sheets and PLA/flax prepregs were combined to produce a hybrid composite (OWPF) and compared to biocomposite of PLA/flax (PF) as well as PP laminate (OW). Tensile, flexural, and impact tests were used to investigate the mechanical properties, while differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) were used to examine the thermal properties of the composites. Results show that composite OWPF exhibited better mechanical properties, such as tensile strength (31.5 MPa), flexural strength (65.4 MPa) and impact strength (6.83 kJ/m2) than composite PF and laminate OW. This could be credited to the improved interfacial bonding of the PP/PLA hybrid matrix and the flax fibres. Reduction in moisture absorption had a significant contribution which resulted in increased interfacial bonding; this is clearly the contribution of the PP/PLA hybrid matrix. Evident from the moisture absorption test, which revealed that composite OWPF absorbed much less moisture (3.36% after 25 days) than composite PF (6.09%). Thermally, composite OWPF showed a higher initial degradation temperature of 303.3°C, however, it experienced multistep degradation, which means it is unstable in such temperatures over a broad range of time. This implies that the mechanical performance of PLA/flax biocomposites can be significantly increased while addressing environmental concerns by incorporating ocean-waste PP and used within normal environmental temperatures.
Reuben Gangas (Wed,) studied this question.