At IRDL, Nahed Hermassi has developed reinforced recycled plastic parts for low CO₂ impact structural applications.
Nahed Hermassi, chercheur·e au sein de IRDL (Institut National Polytechnique de Bretagne).
Thèse soutenue en 2025 à l'école doctorale École doctorale Sciences Pour l'Ingénieur (Lorient ; 2022-....).
Référencée dans le réseau ABES/STAR, cette thèse répond aux critères de rigueur de l'enseignement supérieur français.
Nahed Hermassi's thesis addresses a timely and crucial topic: the recycling of plastics and their valorization in structural applications. In a world where plastic pollution has become a major environmental crisis, this research focuses on the use of recycled materials, notably polyamide 6 (PA6) derived from fishing nets, to reduce the carbon footprint of products while improving their mechanical properties. This raises several essential questions: how can we maximize the use of recycled plastics across various sectors? Which sectors can truly benefit from these innovations, and how can we encourage their adoption?
The results of this research show that reinforcing parts made from recycled PA6 with continuous fibers can offer competitive mechanical properties compared to virgin plastics. Indeed, studies have demonstrated that composites made from recycled PA6 can compete with traditional materials in terms of strength and durability. Thermocompression processes, injection overmolding, and automated fiber placement (AFP) are explored to optimize these materials. These techniques not only improve mechanical performance but also reduce material waste, which is essential in a context of limited resources.
It is also interesting to note that global production of PA6 reaches 6.7 million tons per year. If we manage to increase the recycling rate to 50%, this could lead to a significant reduction in CO₂ emissions. Indeed, every ton of recycled plastic can prevent the emission of several tons of CO₂, representing a considerable opportunity for policymakers to promote policies favoring recycling and the use of recycled composites in key sectors such as automotive and aerospace. For example, companies like Renault and Boeing are already beginning to integrate recycled materials into their production lines, thus demonstrating the viability of these solutions.
The implications of this research go far beyond mere numbers. They touch on plastic waste management and the need for a transition to more sustainable materials. In West Africa, where waste management is a major issue, this study could serve as a model for other similar initiatives. The region faces significant challenges regarding plastic waste, with often inefficient waste management systems. By integrating these materials into production chains, we could not only reduce our environmental impact but also stimulate innovation and job creation in the recycling sector. For instance, training programs for youth on recycling and plastic transformation could be established, thus fostering the emergence of a circular economy.
It is time to rethink our approach to plastics and explore the possibilities offered by recycling. The results of this thesis pave the way for broader reflection on material sustainability and how we can transform our waste into resources. Policymakers must take these research findings into account to develop policies that encourage the adoption of sustainable and innovative solutions. This could include tax incentives for companies that use recycled materials, as well as awareness campaigns to inform the general public about the importance of recycling.
In conclusion, Nahed Hermassi's work is not limited to a simple scientific study. It represents a call to action for a radical transformation in how we conceive and use plastics. By adopting more effective recycling practices and integrating sustainable materials into our production processes, we have the opportunity to build a greener and more responsible future. The challenges are numerous, but solutions exist, and it is time to implement them.
Données clés
- 6,7 millions de tonnes : Production mondiale annuelle de polyamide 6 (PA6)
- 50% : Taux de recyclage recommandé pour réduire les émissions de CO₂
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Sources et accès
Nahed Hermassi. Renforcement local de pièces plastiques recyclées des fibres continues pour des applications structurales à faible impact en C02/kg. Matériaux. Université de Bretagne Sud; Université de Sfax (Tunisie), 2025. Français. ⟨NNT : 2025LORIS736⟩. ⟨tel-05533219⟩