Performances of composites made from different recycled carbon fibre semi-products

Recycled carbon fibres (rCF) were generally chosen for their low price and environmental features. However, performances of composites made of recycled carbon fibres are often too low to compete with lightweight alloys and glass fibre composites materials. As performances of rCF composites depend strongly on the fibres architecture, new semi-products with long and aligned recycled carbon fibres were developed by MANIFICA (Cleansky European Project). The use of long (up to 250mm) and highly aligned recycled fibres now provides rCF composites with excellent mechanical properties. The purpose of this work is to assess the performances of composites manufactured with these new rCF semi-products. Semi-products with distinct architectures developed by MANIFICA are first presented. Then mechanical performances of composite plates manufactured from the different semi-products are evaluated. Results are finally compared in order to identify the effect of the manufacturing parameters of the semi-products on the final composite properties. This crucial information will allow end-users to select the right semi-product to design recycled carbon fibre composite innovative parts

Interaction microstructure/propriétés dans un matériau composite à fibres de carbone recyclées

Il existe aujourd’hui plusieurs techniques efficaces de séparation fibres / matrice pour recycler les fibres de carbone issues de matériaux composites. Les projets de développement de ces techniques thermiques, fluides supercritiques ou chimiques ont donné d’excellents résultats (RECCOMP, HIRECAR, Aerdeco, RECCO), voire [1], [2]. Les techniques les plus efficaces permettent d’obtenir des fibres de carbone de 2° génération avec une très faible perte de propriété (inférieure à 5%) [3], [4]. Le réalignement des fibres recyclées s’avère un point clé dans l’obtention de nouveaux matériaux composites utilisables pour des applications structurelles à forte valeur ajoutée. A ce titre, nous présenterons dans une première partie, un procédé innovant de remise en forme inventé à l’I2M de Bordeaux qui génère des semi-produits de fibres de carbone de 2° génération à partir de morceaux de tissus de carbone post-solvolyse. Dans une seconde partie, nous étudions l’impact de la nature des fibres, du taux de réalignement et de la dispersion de la densité sur la résistance des matériaux composites de 2° génération (contenant des fibres recyclées remises en forme). La maîtrise des relations paramètres de remise en forme qualité du semi-produit résistance du matériau recyclé permettra alors d’envisager des applications structurales pour de la fibre de carbone recyclée. La conclusion de cette présentation est qu’il est impératif d’étudier les facettes chimiques (séparation fibre/matrice) et mécaniques (remise en forme des fibres solvolysées) du recyclage pour concevoir des semi-produits de fibres recyclées et ouvrir les voies d’une utilisation de haute qualité des fibres recyclées. Références : [1] Soraia Pimenta, Silvestre T. Pinho “Recycling carbon fibre reinforced polymers for structural applications: Technology review and market outlook” Waste Management 31 (2011) 378–392 [2] Carbon recycling: a soluble problem » REINFORCED plastics MAY 2009 [3] S.J. Pickering “Recycling technologies for thermoset composite materials—current status” Composites: Part A 37 (2006) 1206–1215 [4] Yongxiang Yang, Rob Boom, Brijan Irion, Derk-Jan van Heerden, Pieter Kuiper, Hans de Wit “Recycling of composite materials” Chemical Engineering and Processing 51 (2012) 53– 6

Recovery and reuse of discontinuous carbon fibres by solvolysis: Realignment and properties of remanufactured materials

Discontinuous carbon fibre tows were recovered after solvolysis of an aeronautic type composite made with RTM6 epoxy resin. A Sohxlet extraction method was used to quantify the organic residue on the fibre tows and showed that less than 3 wt% was remaining on the surface. The recovered tows were therefore reused directly to manufacture a plate with randomly distributed carbon fibres and then three plates with realigned carbon fibres. The latter were then characterised and tested and the results obtained were compared to the material manufactured using the same type of virgin fibres by the same method. The materials made from recycled carbon fibres showed very good properties in comparison to the virgin fibre material, despite the presence of flaws such as quality of the fibre surface after solvolysis, alignment and voids). This is the first time in the open literature that carbon fibres recovered from solvolysis were reused in this way together with characterisation of the resulting materials

Simplification of requalification procedure of outdated carbon/epoxy prepregs and scenarios of reuse

As a result of their combined high mechanical performances and easy processability, carbon/epoxy prepregs are widely used in the manufacture of aerostructures. The resin of these materials is in an intermediate state of polymerisation which makes these materials perishable. Drastic manufacture conditions lead continuously to the generation of expired prepregs that, today, can no more be used in the aeronautic industry nor in other industries. Although requalification procedure can be carried out, its high cost does not always justify such a procedure. This is why large quantities of expired prepregs are send to landfill. The objective of the Cleansky project MANIFICA is to set up a complete recycling chain of carbon fibre composites “from aeronautic waste to innovative composite parts”. The aim of this work is to propose a simplified requalification procedure by avoiding unnecessary tests. These studies are illustrated by property measures on compliant and expired prepregs. The main results were that in most cases, aging induces processing difficulties while mechanical performance remains unaffected. It was also shown that a simpler requalification procedure was possible and that expired prepregs can be reused without loss of performance outside the aeronautical field. Rather than considering expired material as waste, MANIFICA offers several new reuse scenario

Research orientations in design for recovery applied to composite parts

The composite use in industry increases. Despite, composite end of life solutions are still under development. We proposed to address a combined definition of both composite design and composite recycling process. This paper will discuss the needs of multi-disciplinary skills in order to take into account recycling possibilities in the design, and to asset recycling product capabilities by the design requirements. This paper highlights the relation between functional approach by designer, characterization for material and mechanics behavior and recycling process limits, constrains and opportunities.EcoSD networ

Design for recycling problematic : application to composite parts

Purpose: The use of composites in industry is ever- increasing. However, in spite of that, end of life solutions for composites are still under development. In this paper, a solution linking design strategies with a recycling process for composite materials will be proposed. The needs and multi-disciplinary skills required for taking recycling possibilities into account in the early stages of product design and the necessity to standardize product recycling capabilities based on design requirements will be discussed

Optimisation des conditions de mise en oeuvre d'un alliage de polymères ABS-PC recyclé contenant une impureté

La faible présence sur le marché de polymères recyclés issus de produits en fin de vie peut s’expliquer en grande partie par le manque de confiance de la part des industriels envers la qualité de la matière recyclée. En effet la matière recyclée et particulièrement les polymères recyclés, lorsqu’ils proviennent d’un gisement de produits hors d’usage, comme les DEEE peuvent avoir une qualité fluctuante, notamment en raison des impuretés qu’ils peuvent contenir. Or, les conditions de mise en œuvre peuvent avoir une grande influence sur la qualité d’un alliage de polymères de 2° génération. Ce deuxième cycle de remise en forme peut dégrader la matière recyclée ou bien, si il est correctement maîtrisé, il peut permettre de lisser les propriétés de la matière en masquant la présence de certaines impuretés [1]. Dans la première partie de cette étude, nous montrons d’une part l’impact des paramètres d’injection sur la morphologie complexe d’un alliage de polymères (ici l’ABS-PC) contenant une impureté ; et d’autre part, nous expliquons les relations entre ces morphologies et la résistance au choc du matériau recyclé. Dans une seconde partie, nous montrons comment il est possible, après optimisation des paramètres de mise en œuvre de l’ABS-PC recyclé de réaliser une matière de seconde génération aux propriétés stables malgré la présence d’une impureté. Nous montrons dans cette étude que la maîtrise des conditions de recyclage permet au matériau recyclé de tolérer la présence de certaines impuretés sans modification significative de ses caractéristiques mécaniques. L’objectif à terme est d’être en mesure de produire un matériau recyclé de qualité environnementale et technique et apte à être remis en forme et à subir un nouveau cycle de vie. Références : [1] ARNOLD et al. ; Polymer testing, Vol 29, N°4, 2012 [2] VILAPLANA FJ et KARLSSON S.; Macromol Mater Eng, Vol 293, N°4, 200

The V471A polymorphism in autophagy-related gene ATG7 modifies age at onset specifically in Italian Huntington disease patients

The cause of Huntington disease (HD) is a polyglutamine repeat expansion of more than 36 units in the huntingtin protein, which is inversely correlated with the age at onset of the disease. However, additional genetic factors are believed to modify the course and the age at onset of HD. Recently, we identified the V471A polymorphism in the autophagy-related gene ATG7, a key component of the autophagy pathway that plays an important role in HD pathogenesis, to be associated with the age at onset in a large group of European Huntington disease patients. To confirm this association in a second independent patient cohort, we analysed the ATG7 V471A polymorphism in additional 1,464 European HD patients of the “REGISTRY” cohort from the European Huntington Disease Network (EHDN). In the entire REGISTRY cohort we could not confirm a modifying effect of the ATG7 V471A polymorphism. However, analysing a modifying effect of ATG7 in these REGISTRY patients and in patients of our previous HD cohort according to their ethnic origin, we identified a significant effect of the ATG7 V471A polymorphism on the HD age at onset only in the Italian population (327 patients). In these Italian patients, the polymorphism is associated with a 6-years earlier disease onset and thus seems to have an aggravating effect. We could specify the role of ATG7 as a genetic modifier for HD particularly in the Italian population. This result affirms the modifying influence of the autophagic pathway on the course of HD, but also suggests population-specific modifying mechanisms in HD pathogenesis

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Design for recycling problematic : application to composite parts

Purpose: The use of composites in industry is ever- increasing. However, in spite of that, end of life solutions for composites are still under development. In this paper, a solution linking design strategies with a recycling process for composite materials will be proposed. The needs and multi-disciplinary skills required for taking recycling possibilities into account in the early stages of product design and the necessity to standardize product recycling capabilities based on design requirements will be discussed