All the industry from the Polymers Area, change their sourcing strategy due to 2 constraints : fossils resources availability which are the basis of the « regular » Polymers and the incentives in the reduction of the energy consumption. This double motivation drive the car makers R&D Departments and their suppliers to evaluate and use natural fibers reinforcement as an answer to this double objective : their length is by itself a powerful mechanical reinforcement media which also leads to a very interesting density decrease. Also their natural sourcing decrease the fossil resources needs. A great number of R&D collaboratives actions made this challenge happen focusing on the application, the fiber itself as raw material, its preparation, on the characteristics of the fibers based composite for such or such application even on the supply chain, but without accounting on the decohesion phenomena. This is a key step in the compounding stage. Mastering decohesion is important to keep fibers length which is their main attribute as mechanical reinforcement additives. The DEFIBREX project focus on this topic with an ambitious and generic methodology, centered of the natural fibers decohesion phenomena analysis under mechanical constraints. This analysis must lead to a decohesion behavioral model which should be capable to describe a wide types of fibers and mechanical constraints ranges. This model will be validated by experiments run on a variety of fibers.( sourcing, physico-chemical treatments...) with the ambition of proposing the widest global classification of the various used fibers in the industry. To reach these ambitious objectives, the DEFIBREX partnership associate complementary scientific skills (sourcing, pre-treatment with FRD and INRA, process and modelisation with CEMEF and µTomography morphologic analysis (I2M) , with industrial partners (K-TRON, SCC, CLEXTRAL et FAURECIA,) whose contribution will be to help reaching the project objectives and answering questions such as : how to feed a twin-screw extruder without degrading fibers length ? How to set a twin-screw extruder in such a way to maximize mixing efficiency and without degrading fibers length ? What is the functionality increase that can be expected on such injected pieces, and what is the dimensional saving that we can account ? How to deliver and disseminate the behavioral model to industrials users ? To answer those questions, the DEFIBREX project is self organised in 5 work packages : Fibers will be sourced and analyzed on the morphological, mechanical and bio-chemical point of view in WP1. WP2 is dedicated to phenomenological study of the compounding process on a lab scale level with a wide range of fibers types. The compound characterization process by these experiments will be used as input for WP3 whose objective will be to set the behavioral model and its declination as a numerical model in the Twin-Screw extruder simulation program LUDOVIC (as a media for dissemination). In parallel, a fibers classification will be be proposed to establish and sort their polymers reinforcement capability, as well as the compound processability evaluation. The WP 4 is focusing on the industrial scale : fibers feeding, productions of composites samples, compound characterization in order to wider the application range of the behavioral model. Also, the WP4 will produce compound to inject real automobile parts with the objective to evaluate the performance increase of such new parts. This will be achieved in the WP5. Classically, the WP6 will be the project coordination work package. Finally, DEFIBREX is expected to contribute to the knowledge and understanding of the natural fibers decohesion phenomenum and delivering to the manufacturing industry a key technological breaktrough.

The industry of the tyre built itself since the end of the XIXth century thanks to the development and the adaptation of innovative technologies, like for example the radial tire or the introduction of silica in the energy-saving tires. The French Factory of Pneumatics Michelin is one of the world leaders of the tyre. But this business sector is strongly competitive, because new actors stemming from emerging countries appear and win consequent market shares on the historic leaders. While in 2000 the Chinese manufacturers represented only a marginal part of the market, in 2011 the volume of tires produced by these last ones amounts to the total volume of 3 world leaders. In this context, it is essential to innovate on products, in particular in the field of the materials for the development of the low energy-saving tires (grading A). Today, the main development limitation of new rubbers is the industrial processing. In particular, when the new silica-filled elastomers are extruded into profiles, volume defects appear on extrudates, preventing from the feasibility of such formulations. Michelin thus wishes to open new ways of innovation, at present forbidden by these industrial constraints. For that purpose, it is necessary to understand the causes of these extrusion instabilities and to develop knowledge on the nanostructure and the properties of these compounds. This kind of study already exists in the field of the thermoplastic polymers but in the field of nano filled elastomers. Our final goal is to obtain physical multi-scales criteria that describe the rheologic behaviour of these materials, connected with microstructural and molecular parameters, so as to determine the link of causality with the appearance of volume instabilities in extrusion.

Controlling fine-scale surface texture is a new frontier for polymer injection moulding. The requested functionalities may be connected with visual or haptic aspects for consumer goods, or with more technical ones such as wetting, adhesive or frictional properties. The biomedical field by itself encompasses a very wide potential of applications for such technologies, with stringent technical specifications on mass-produced consumables. Our choice in TopoInjection is to work on injectable drug delivery devices, to focus on a specific industrial application – yet the results should be widely applicable. Such a system must be able to deliver active biological substances with a high precision, must meet strict requirements on tribological properties, watertightness, chemical stability, biocompatibility, and must be compatible with mass production. A preliminary study of the tribological behaviour of the contact between an elastomer (piston) and a rough surface (body) in a syringe suggested which textures should be ideal for polymer surfaces. The next step is now to be able to manufacture surfaces with a reproducible texture throughout the required scale range (100 nm – 100 µm) on polyolefin pieces produced in large series. The aim of the project is to develop a polymer injection moulding process giving the required textures thanks to a combination of four sets of parameters: 1) the mould surface texture, 2) the mould surface chemistry, 3) the physical and chemical properties of the injected polymer, 4) the injection moulding process parameters. To reach this goal, TopoInjection shall focus on the following keypoints: • develop a new mould surface texturation process, using femtosecond Laser beams; • develop experimental and numerical tools to understand the polymer melt flow at the microscale, together with the evolution of the surface upon unmoulding; • disclose the interactions between the mould surface chemistry, modified by PVD hard coatings, the polymer physico- chemistry and the interface behaviour. This deductive approach will probably not yield all the necessary elements for the solution of the problem. It will therefore be completed by a more inductive, empirical approach based on trials on an instrumented injection moulding press. The results from the deductive approach will be integrated continuously to orient real-size tests. This ambitious project gathers three academic laboratories (LTDS, LaHC, CEMEF-ARMINES), an engineering school (ITECH) and two industrial partners (HEF, Becton Dickinson, HEYRMOULES). Most have both internationally recognised expertise in the scientific fields of interest and a long experience of collaborative projects

Single screw extruder is the continuous equipment mostly used in the domain of polymer processing, used for final or semi products. Among the derived techniques, the Buss Kneader has the particular design of a barrel equipped with pins on its inner surface coupled to a discontinuous screw (in order to leave room to barrel pins) that translates back and forth while rotating. This coordinated kinematics leads to complex flows ensuring efficient mixing and homogeneity of material. This technology is indeed very adapted to thermosensitive materials, highly filled compounds or for plasticizing PVC compounds. New generation compounds not only have to meet required technical specifications of durability, aesthetics, safety, maintenance but also have to ensure widened features: fire-proofing properties, health, bacteriostatic and antistatic constraints. Formulations are more and more complex and deadlines shorter and shorter. In spite of this, equipments type Buss kneaders are considered most of the time as black boxes. The effects of the conditions of flow (due to geometry, to kinematics) on materials, their plasticizing and mixing are very difficult to quantify. It is well known today that numerical simulation is the required tool to answer the questions of understanding, control and optimization of industrial processes. To be predictive, numerical simulation needs to integrate pertinent flow models as well as material evolution models. This second point, before being mathematically written, must be studied and characterized. On the basis of this approach, LUCOMAX is devoted to control all various phenomena occurring in a type Buss kneader, then to set up a simulation tool able to perpetuate the knowledge, whose value analysis will be performed by end-users. To reach these objectives, the LUCOMAX project - merges three industrial companies in the field of flooring and interior coverings (Gerflor), cable-manufacturing (Acome) and chemistry (Arkema); a software edition company (SCC) and two research laboratories specialized in the study of materials (Ingénierie des Materiaux Polymères) and processes modeling and simulation (CEMEF). is organized in 4 technical tasks and one task for project management. Task 1 is dedicated to the study of the phenomenological aspects of the flow in Buss type kneaders and materials characterization. It will define measurable objective variables able of link process conditions to product quality; Task 2 sets up a mechanical model of global approach allowing flow simulation and quantification of the objective variables defined in the first task; The integration of this model into an existing software platform available to the industrial users is the task 3. The selected software platform is the one of the software Ludovic® (dedicated to the flows in a twin-screw corotative extruder) because the global mechanical model will be close to Ludovic®'s one and because the industrial problems for these equipments are similar; Task 4, leaded by industrial end users, sets up the validation configurations and analyze the added value brought by the three previous tasks regarding the industrials practice. Within subtask 5, project coordination for administrative and technical points of view will be done in order to ensure the best work conditions. Three main points will be carried out: - project management in accordance with the work program - edition of progress reports - internal and external communication.