- Title
- Toughened wood plastic composites for low technology and advanced manufacturing applications
- Creator
- Mabutho, Briswell
- Subject
- Plastic-impregnated wood
- Subject
- Polymeric composites
- Date Issued
- 2024-12
- Date
- 2024-12
- Type
- Doctoral theses
- Type
- text
- Identifier
- http://hdl.handle.net/10948/69360
- Identifier
- vital:77225
- Description
- The utilization of wood plastic composites (WPCs) has increasingly emerged as an appealing alternative for products where traditional wood and conventional composites would typically be used. This is primarily due to their cost-effectiveness, mouldability, recyclability, renewability, and potential biodegradability. However, the incorporation of wood flour (WF) in thermoplastics to produce WPCs presents several challenges, two of which are addressed in the current study: the WF-thermoplastic matrix adhesion, and the resulting brittleness of the WPC. The hydrophilic nature of WF filler and the hydrophobic polypropylene matrix, which typically lead to poor mixing due to their differing surface energies. Consequently, the current research focuses on enhancing WF-matrix (i.e. polypropylene, PP) adhesion and dispersion through compatibilization using maleic anhydride grafted polypropylene (MAPP). Additionally, the brittleness of WPC, exacerbated by the WF content, is addressed through the incorporation of crumb rubber (CR), a process commonly referred to as "toughening" the WPC. Prior to the use of CR in WPCs, optimization of the CR amount and compatibility within the PP-matrix were conducted to establish a toughening system that would achieve the highest impact strength without significantly affecting the tensile strength. The CR was compatibilized by employing dynamic vulcanization of varying amounts of ethylene propylene diene monomer rubber (EPDM) in the CR/PP blends using both sulphur and dicumyl peroxide cure systems. The results indicated that the sulphur dynamic cure system exhibited higher crosslinking efficiency, as reflected by the highest impact strength. Furthermore, to enhance WPC processability and adhesion, WF alkalization was conducted following a central composite design to optimize treatment temperature, time, and alkali concentration. This optimization resulted in improved WPC processability and mechanical properties at mild alkalization conditions. Subsequently, the optimum CR/EPDM dynamic cure system was employed to toughen both untreated and alkalized WPCs, resulting in toughened WPCs with improved thermal stability, impact strength, and elongation at break, while the tensile strength was only slightly compromised.
- Description
- Thesis (PhD) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (267 pages)
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
- Rights
- All Rights Reserved
- Rights
- Open Access
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NMU School of BioMolecular and Chemical Sciences
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | MABUTO, B.pdf | 7 MB | Adobe Acrobat PDF | View Details Download |