Related resources
Search for item elsewhere
University researcher(s)
Academic department(s)
NONWOVEN FLAX FIBRE REINFORCED PLA BIODEGRADABLE COMPOSITES
[Thesis]. Manchester, UK: The University of Manchester; 2014.
Access to files
-
FULL-TEXT.PDF (pdf)
Abstract
The awareness of environmental sustainability drives the composite industry to utilize natural fibres. Natural fibres are a readily available resource with a relatively low price. In this study natural fibre flax reinforced polylactic acid (PLA) biocomposites were made using a new technique incorporating an air-laying nonwoven process. Flax and PLA fibres were blended and converted to fibre webs in the air-laying process. Composite prepregs were then made from the fibre webs. The prepregs were finally converted to composites by compression moulding. The relationship between the main process variables and the properties of the biocomposite was investigated. It was found that with increasing flax content, the mechanical properties increased. As the moulding temperature and moulding time increased, the mechanical properties decreased. The physical, thermal and morphological properties of the biocomposites were also studied. The appropriate processing parameters for the biocomposites were established for different fibre contents.The biodegradability and water absorption properties of the composites were evaluated. The composites were incubated in compost under controlled conditions. The percentage weight loss and the reduction in mechanical properties of PLA and biocomposites were determined at different time intervals. It was found that with increasing flax content, the mechanical properties of the biocomposites decreased more rapidly during the burial trial. The increasing of flax content led to the acceleration of weight loss due to preferential degradation of flax. This was further confirmed by the surface morphology of the biodegraded composites from Scanning Electron Microscope (SEM) image analysis. This study also investigated the manufacturing of 3D PLA/Flax nonwoven prepregs by using a new system of 3D nonwoven web formation, and 3D biocomposite was made using these prepregs. A new mould unit for web and a new aluminium mould for biocomposite were developed. The physical properties of 3D biocomposites were investigated and it was found that there is no significant difference between 2D and 3D biocomposites in density and void content. The effects of fibre content and processing variables on the crushing behaviour, energy absorption and failure mode of 3D shell biocomposites were experimentally studied.