As most thermoset material, phenolic molding compound (PMC) wastes are an environmental problem. Very few recycling solutions have been proposed so far for this type of material. A mechanical recycling method to valorize these materials is proposed in this work. It relies on the use of phenolic waste as filler in thermoplastic. Such phenolic filler can increase mechanical properties (tensile, flexural) of the matrix, and be used in substitution of traditional particulate fillers such as calcium carbonate or talc. In this study, several morphological parameters influencing the final mechanical properties of a PMC-filled polypropylene (PP) micro-composite are studied, such as filler loading rate, particles size distribution of the filler, and interfacial adhesion between the filler and the matrix. Some structural parameters are also studied and linked with mechanical properties, such as dispersion of the filler and crystallinity of the matrix. Finally, the properties of PMC-filled PP are compared with CaCO 3 -and talc-filled PP.

End of life electrical equipment is a continuously increasing source of waste in our modern society, and constitute an environmental problem. Understanding this type of waste flow is important to devise proper dismantlement and sorting strategies, and to maximize the material recovery rate and valorization. In this work, a waste pool constituted of electrical meter was studied. The specificities of this equipment in term of design were enlightened, and the overall material composition was determined. An emphasis was put on the characterization of the plastic fraction, both in term of plastic type and presence of regulated substances. It revealed that this fraction is mostly composed of phenolic molding compound (PMC), a thermoset material, which is troublesome in term of recycling. A material valorization solution through mechanical recycling is proposed , consisting in using PMC as functional filler in a thermoplastic matrix. A comminution scheme to obtain such filler is presented in this work, and the comminuted products are characterized. Through 2 or 3 steps of comminution, particle size below 50 µm can be obtained, which is expected to be a sufficient size for incorporation in a thermoplastic matrix.

Phenolic molding compounds (PMC), also known as Bakelite TM , are the first synthetic plastics ever produced. They are still in use today in electrical, household and automotive applications. However, one major drawback of PMC is their lack of recycling option. Indeed, landfilling is still the main route of disposal, which constitutes a serious environmental burden. A new alternative recycling method is the use of comminuted PMC as filler in a thermoplastic matrix, in order to improve its mechanical and thermal properties. Several key parameters of the manufactured composite structure are the fillers size distributions, their loading percentage, and the adhesion at the filler/matrix interface. These parameters are related to mechanical properties of the composites, such as tensile strength. In this work, a polypropylene matrix is filled with 20% by weight of comminuted PMC (d 50 = 24μm) functionalized with 3% by weight of PP-g-MA to improve matrix/fillers compatibility. A FE model was developed from the mechanical behavior of each component. PP matrix and PMC fillers are individually characterized from tensile tests instrumented with photomechanics for the matrix characterization and their behaviors were modelled through a set of numerical parameters (elasto-visco-plasticity with a Gurson criterion behavior for the matrix and damage elasticity for the fillers). Numerical simulations at several strain rates were conducted on representative volume element with various microstructures. Comparison between the determinist model results and the experimental data (strength, volumetric variation) shows that this type of modelling could be a predictive tool in order to design particulate composites with optimized mechanical properties. Hence, it is an adequate way to understand micromechanisms of deformation (damage, cavitation).

The use of bio-based material is now widespread in insulation concrete, for example hemp concrete. The bio-based materials in concrete provide many advantages: lightness, sound and thermal insulation, hydrothermal regulation while contributing to a reduction in the environmental impact due to the carbon capture during the plant growth. The development of materials incorporating plant is therefore an important objective for the construction. The next step will be to introduce bio-based materials in structural mortars and concretes. The project FIBRABETON proposes to substitute synthetic or metallic fibers by natural fibers in screed and slab. After a selection of biomass on the resources availability, separation and fractionation are the key step in processing to obtain technical natural fibers. Bulk fiber shaping and packaging methods for easy handling and transportation are tested. Then, functionalization of technical natural fibers by physical & chemical treatments to improve the durability with cement paste is carried out. The second step concerns the introduction of treated or not treated fibers in mortar and concrete formulations. The variation of the nature of the biomass, fibers shape and dosage in concrete are studied. The workability, the compressive strength and withdrawal resistance are measured in order to obtain the best formulation parameters. The evolution of properties over time is also evaluated. The project FIBRABETON is carried out with ESTP, FRD and Vicat and is subsidized by ADEME, Grand Est region and FEDER.

This work, which is part of the FIBRABETON project, aims to anti-fissuration screed formulations proposition based on natural fibers and comparing these formulations to a synthetic fiber-screed formulation. Different natural fiber (hemp, flax, miscanthus and bamboo) with contents rangingfrom 0.4% to 0.8% were tested. The spread (slump), the shrinkage and mechanical strength (flexural and compressive) studies were carried out. SEM images of natural fibers and natural fibers screed formulation were analyzed. Overall, it is found that all natural fibers screed formulations tested, have shown better behaviour than the synthetic fibers screed formulation in point of view workability, shrinkage and mechanical properties. The lowest shrinkage value is found in the case of the H5 (5 mm long hemp fibers) screed formulation. Generally speaking, the mechanical strength values (flexural and compressive) are more or less similar between natural soft fibers (hemp and flax) and rigid fibers (miscanthus and bamboo). Taking in account slump, shrinkage and mechanical behavior, the proposed good compromise in this work is the H5 screed formulation.