Originally developed for high-tech applications in the aeronautic and aerospace industry, carbon/epoxy composites have been increasingly used in the automotive, leisure, and sports industries for several years. Nevertheless, the carbon reinforcement is an expensive constituent, and it has been recently shown that it is also the most environmentally impacting in a composite part manufacturing. Recycling these materials (even restricted to the reinforcement recovery) could lead to economic and environmental benefits, while satisfying legislative end-oflife requirements. The solvolysis of the matrix by water under supercritical conditions is an efficient solution to recover the carbon fiber reinforcement with mechanical properties closed to the ones of virgin fibers. This paper aims at demonstrating the environmental feasibility of the recycling of carbon fiber/thermoset matrix composites by solvolysis of the matrix in supercritical water. This demonstration is based on life cycle assessment that evaluates benefits and environmental challenges of this recycling loop.

No abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Methods In order to validate the choices, we used a life cycle assessment (LCA) Bfrom cradle to grave^of the hull. This LCA is based on the comparison of the following different materials used: aluminum, composite, exotic wood, and maritime pine. This study is based on the construction of an 18-mlong passenger transport boat. These evaluations were carried out with respect to ISO 14040 standards, beginning with an existing database and measurements taken on the building and production sites.Results and discussion Our results demonstrate the benefits of using a wood-based hull compared with other materials. Moreover, the results show that the maritime pine used in replacement of imported exotic woods is more favorable from both economic and environmental points of view. This LCA allowed us to characterize precisely the stages in the life cycle of a passenger boat and to propose a hierarchy of the different materials under comparison for the purposes of boat building.Conclusions The recommendations and lines of progress highlighted by this study will allow us to enhance the efficiency of upcoming constructions and to promote the ecodesign conception in the boatyard.

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This is an author-deposited version published in: https://sam.ensam.eu Handle ID ABSTRACTIn order to decrease both energy consumption and CO 2 emissions, the automotive, aeronautics and aerospace industries aim at making lighter vehicles. To achieve this, composite materials provide good opportunities, ensuring high material properties and free definition of geometry. As an example, for cold applications, the use of carbon fiber/thermoset composites is ever increasing, in spite of a high fiber price. But in a global and eco-friendly approach, the major limitation for their use remains their potential recyclability. Recycling a composite means having a recycling technology available, getting a dismantle solution and an access for the product, and disposing identification plus selection possibilities to the materials. Thus, carbon fibers recovery (i.e. recycling and re-processing) would both help design engineers to balance energy efficiency and cost, and open new opportunities for developing second-life composites, dedicated to the manufacture of medium or low loaded parts (non-structural in many cases).A first section presents an overview of composite recycling possibilities. Indeed, environmentally and economically, composite incineration is not attractive (even with an energetic valorization), let-alone burying. Reuse and recycling thus remain the two most interesting options.Aeronautics offers a high potential in terms of fiber deposit. In southwest France, composites recycling will increase in terms of quantity due to dismantling platforms TARMAC (dedicated to civil aircraft applications) and P2P (for the disassembly of ballistic weapons). In addition, from a technical point of view, and even if end-of-life solutions for composites still remain under development, solvolysis (i.e. water under supercritical conditions) already offers the opportunity to recover carbon fibers. The resulting recyclate retains up to 90 percent of the fiber's mechanical properties.A second part will explore the recycling to design issue (i.e. how recycling processes have to balance the previous aspects of the end-of-life proposal).The recycler clearly becomes a new supplier in the carbon fiber lifecycle, by revalorizing wastes with alternatives to burning. Moreover, increasing carbon fiber shelf life reduces its product life impact. Finally, promoting carbon fiber end-of-life would ensure to link aeronautics, automotive, and leisure and sports industries; but one can create demand for recycled reinforcement, by packaging it in useful and attractive forms for those end-users (e.g. pseudo-continuous fiber, felt, strips, bands, patches, etc.).These sections will be enlightened by several examples from collaborations between I2M and local industries. NOMENCLATURE 1G: first generation material 2G: second generation material  : angle (cylindrical coordinate)

Eco-design is a key trend in industry today. DCNS, a major French shipbuilder, has taken a position in this market thanks to a consortium of several concerned specialists: Arts et Métiers ParisTech, Ifremer, SITA Suez, and Bureau Veritas. The purpose is to create a tool to assess the impacts on the aquatic environment, but also an eco-design tool making it possible to improve design. Based on life cycle analysis (LCA) principles, it is improved by a specific ecoindicator for the maritime environment and the possibility of a return to design at the design stage. This tool is currently being developed by a computer engineer. The functionalities proposed and expected in the tool requirements are being tested by this development.