Conducted jointly by UL and UAC, this research explores the valorization of plastic and wood waste into durable composites.
Key Takeaway: Conducted jointly by UL and UAC, this research explores the valorization of plastic and wood waste into durable composites.
Jonathan Guidigo, researcher at LERMAB (Université de Lorraine).
Thesis defended in 2017 at the doctoral school RP2E - Ecole Doctorale Sciences et Ingénierie des Ressources, Procédés, Produits, Environnement.
This research was conducted as part of a Franco-Beninese joint supervision (cotutelle), ensuring it is simultaneously grounded in local field conditions and international academic standards.
Context and Problem Statement
This study focuses on wood-polymer composite (WPC), a composite material made from plastic waste and wood sawdust. This research addresses the growing need for sustainable solutions in the construction sector, particularly in regions where traditional construction materials are often costly or hard to access. Plastic waste, ubiquitous in urban areas, poses a major environmental problem. By incorporating this waste into composite manufacturing, it becomes possible to reduce its impact while creating valuable materials.
Wood-polymer composite materials can represent a viable alternative to conventional construction materials. The extrusion method used in this study aims to improve the mechanical properties of the composites compared to existing artisanal methods. This research aims to physico-mechanically characterize these composites in order to determine their potential for application in sustainable construction.
Methodology
The methodology adopted for this research includes several key steps. First, wood-polymer composite samples were manufactured by extrusion using defined proportions of plastic waste and wood sawdust, reflecting the composition of waste available in Cotonou, Benin. The proportions of wood sawdust incorporated into the polymer matrix were 20%, 25%, 28%, and 30%.
Physico-mechanical analyses were carried out to evaluate the properties of the WPC samples under compression, bending, and tension. The methods used include thermogravimetric analysis to understand the thermal stability of the materials, as well as bending, compression, and tensile tests to assess mechanical strength. In parallel, an analysis of the wood sawdust was carried out to determine its chemical composition and mechanical properties.
The results obtained were compared with those of samples manufactured using artisanal methods, allowing an assessment of the effectiveness of extrusion in improving the composite's characteristics.
Key Findings
The study's results indicate that adding wood sawdust to the thermoplastic matrix significantly improves the mechanical properties of wood-polymer composites. Indeed, the wood sawdust acts as a reinforcement under compression and bending loads, increasing the composite's stiffness. In tensile tests, however, the sawdust behaves more like a filler, playing a different role depending on the type of load applied.
WPC samples manufactured by extrusion show superior mechanical properties compared to samples made using artisanal methods. Thermogravimetric analyses revealed that artisanal samples are exposed to temperatures exceeding 300°C, which causes degradation of the polymers and wood sawdust, compromising their integrity and durability. By comparison, composites made by extrusion show better resistance to thermal degradation, suggesting greater viability for construction applications.
The results also show that the proportions of wood sawdust influence the composite's mechanical properties. Increasing the amount of wood sawdust up to 30% improves stiffness and strength under compression and bending, highlighting the appeal of these materials for the sustainable construction sector.
Discussion and Outlook
The results of this research highlight the potential of wood-polymer composites as sustainable construction materials, particularly in the African context, where resources are limited and plastic waste represents a major environmental issue. Using plastic waste and wood sawdust to manufacture composites offers a dual opportunity: valorizing waste while developing construction materials with satisfactory mechanical performance.
Industrializing the production of wood-polymer composite could help meet growing demand for construction materials while reducing the ecological footprint. However, it is essential to conduct further studies to optimize formulations and production processes, in order to guarantee the durability and performance of the composites under real-world usage conditions.
Finally, this research paves the way for initiatives promoting the use of composites in sustainable construction. Collaboration between academic institutions, industry players, and governments will be crucial to support this transition. Disseminating the results and technologies developed could encourage the adoption of more environmentally friendly construction practices, strengthening the positive impact of wood-polymer composite on waste management and sustainability in the construction sector.
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Sources and Access
Jonathan Guidigo. Caractérisation physico-mécanique d’un composite bois polymère. Science des matériaux [cond-mat.mtrl-sci]. Université de Lorraine; Université d'Abomey-Calavi (Bénin), 2017. Français. ⟨NNT : 2017LORR0229⟩. ⟨tel-01907728⟩