In the context of a circular economy, one can observe that (i) recycling chains are not adapted enough to the end-of-life products they have to process and that (ii) products are not sufficiently well designed either to integrate at best their target recycling chain. Therefore, a synergy between product designers and recycling-chains stakeholders is lacking, mainly due to their weak communication and the time-lag between the product design phase and its end-of-life treatment. Many Design for Recycling approaches coexist in the literature. However, to fully develop a circular economy, Design from Recycling also has to be taken into account. Thus Re-Cycling, a complete circular design approach, is proposed. First, a design for recycling methodology linking recyclability assessment to product design guidelines is proposed. Then, a design from recycling methodology is developed to assess the convenience of using secondary raw materials in the design phase. The recyclability of a smartphone and the convenience of using recycled materials in a new cycle are both analyzed to demonstrate our proposal. The Fairphone 2^® and its treatment by the WEEE French takeback scheme are used as a case study.

Plastics make up a significant proportion of the stream of the European Waste of Electric and Electronic Equipment (WEEE), yet the use of recycled plastic materials is very low in new manufactured products. A description of the WEEE waste stream in Europe is given, with a focus on the plastic materials commonly found in WEEE that include four principal polymers: polypropylene (PP), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS) and polystyrene (PS). Furthermore, the legislative aspects related to WEEE and plastics recycling in Europe are complex, and numerous norms have been dictated by the European Commission. These norms are crucial to the sector of polymer recycling and production in Europe. Moreover, an overview of the entire treatment chain is presented. More specifically, each step of a typical recycling chain is introduced, with a focus on the sorting of plastics and the separation of polymers. Lastly, the influence of contaminants in the plastic fraction is discussed, both in terms of polymer particles and unwanted additives. By showing the impact of the purity rate on the mechanical properties of recycled plastics, the consequences of inadequate end-of-life treatment for WEEE-plastics is highlighted, hence linking the quality of recycled plastics to the separation step and the re-compounding of recycled granulates.

The definition of the recycling and recyclability rates used today relies too heavily on the mass of the recycled materials, to the disadvantage of less dense materials such as polymers. In order to help with this issue, two indices have been created to, respectively, evaluate the retrievability of materials in their end-of-life stage and their reintegrability in new equipment once they have been recycled. These two indices comprise four indicators each, which are themselves divided into 23 sub-indicators. The six formal mathematical principles of the construction of these entities are presented, along with the formulas used for their calculation. Then, a case study is presented: the data of an equipment from a French EEE and sports and leisure distributor have been collected, and all sub-indicators, indicators and indices have been calculated for this equipment, hence assessing the retrievability and reintegrability of its constitutive materials. In conclusion, the precise nature of the indicators and sub-indicators has allowed us to give eco-design recommendations on different aspects of the design process, such as the choice of materials, the mechanical connections and modularity of the product, and its insertion into the waste treatment chain.

2.4 Conclusion was published in Impacts écologiques des Technologies de l'Information et de la Communication on page 124.

3.4 Conclusion was published in Impacts écologiques des Technologies de l'Information et de la Communication on page 177.