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

Mesure et prédiction des déformations et contraintes résiduelles lors du refroidissement d’un stratifié composite thermoplastique

International audienceCooling of thermoplastic composite parts inevitably leads to the development of residual stresses, which may have negative consequences on the final part health. Modelling their development during cooling therefore appears as an interesting solution to optimize the process parameters and limit the stresses intensity. This study proposes a coupled model accounting for heat transfer, crystallization kinetics and mechanical behavior of thermoplastic composite laminate. This latter is treated according to the modified lamination theory, which is for the first time adapted to the study of a thermoplastic composite during cooling, with temperature dependent properties. This is made possible by the use of an incremental linear elastic law, which also accounts for the crystallization shrinkage and thermal expansion of the material. The model is applied to the study of an unsymmetric laminate, which leads to estimated stress and strain states. These latter are compared with experimentally measured strains, highlighting an excellent agreement which validates the proposed moLe refroidissement des pièces composites thermoplastiques durant leur mise en oeuvre mène inexorablement au développement de contraintes résiduelles. Ces contraintes peuvent être néfastes pour la santé finale de la pièce et il convient de prédire leur développement au cours du procédé afin d'optimiser celui-ci et ainsi limiter l'impact des contraintes sur le matériau. Cette étude propose un modèle de prédiction du développement des contraintes résiduelles au cours du refroidissement d'un composite thermoplastique à fibres continues de verre et matrice PA66. Celui-ci prend en compte les transferts thermiques, la cinétique de cristallisation ainsi que le comportement mécanique du composite au cours de son refroidissement. Ce dernier est traité à l'aide de la théorie modifiée des stratifiés qui est adaptée pour la première fois au refroidissement d'un composite thermoplastique dont les propriétés thermomécaniques varient avec la température. Ceci est rendu possible à l'aide d'une formulation incrémentale de la loi de comportement linéaire élastique, prenant en compte les retraits d'origine thermique et de cristallisation. Appliqué au cas d'un empilement asymétrique, le modèle permet de prédire contraintes et déformations résiduelles. Ces dernières sont comparées à des mesures expérimentales pour évaluer la fiabilité du modèle développédel

A targeted next-generation sequencing assay for the molecular diagnosis of genetic disorders with orodental involvement.

BACKGROUND: Orodental diseases include several clinically and genetically heterogeneous disorders that can present in isolation or as part of a genetic syndrome. Due to the vast number of genes implicated in these disorders, establishing a molecular diagnosis can be challenging. We aimed to develop a targeted next-generation sequencing (NGS) assay to diagnose mutations and potentially identify novel genes mutated in this group of disorders. METHODS: We designed an NGS gene panel that targets 585 known and candidate genes in orodental disease. We screened a cohort of 101 unrelated patients without a molecular diagnosis referred to the Reference Centre for Oro-Dental Manifestations of Rare Diseases, Strasbourg, France, for a variety of orodental disorders including isolated and syndromic amelogenesis imperfecta (AI), isolated and syndromic selective tooth agenesis (STHAG), isolated and syndromic dentinogenesis imperfecta, isolated dentin dysplasia, otodental dysplasia and primary failure of tooth eruption. RESULTS: We discovered 21 novel pathogenic variants and identified the causative mutation in 39 unrelated patients in known genes (overall diagnostic rate: 39%). Among the largest subcohorts of patients with isolated AI (50 unrelated patients) and isolated STHAG (21 unrelated patients), we had a definitive diagnosis in 14 (27%) and 15 cases (71%), respectively. Surprisingly, COL17A1 mutations accounted for the majority of autosomal-dominant AI cases. CONCLUSIONS: We have developed a novel targeted NGS assay for the efficient molecular diagnosis of a wide variety of orodental diseases. Furthermore, our panel will contribute to better understanding the contribution of these genes to orodental disease. TRIAL REGISTRATION NUMBERS: NCT01746121 and NCT02397824.journal articleresearch support, non-u.s. gov't2016 Feb2015 10 26importe

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Overmolding of a thermoplastic composite in industrial condtions - Parameters influence onthe adhesion quality

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Overmolding of a thermoplastic composite in industrial condtions - Parameters influence onthe adhesion quality

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Experimental determination and modeling of transformation kinetics

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Phase change kinetics within process conditions and coupling with heat transfers

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Phase change kinetics within process conditions and coupling with heat transfers

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Simulating polymer crystallization in thin films: Numerical and analytical methods

International audienceIn this paper, a general numerical method to simulate polymer crystallization under various conditions is proposed. This method is first validated comparing its predictions with well-validated analytical models in infinite volumes. Then, it is compared to Billon et al. validated model for thin films, without or in presence of transcrystallinity on the films surfaces. It is also compared with Chenot et al. model for thin films, proposed in a conference in 2005 and never yet compared with other methods. Finally, it is also compared with an extension of this model for the transcrystalline case. These models are valid for general nucleation cases (not only sporadic or instantaneous), and can be used for any thermal conditions. All the numerical and analytical results are consistent, except in a case which is shown to be out of the validity domain of the transcrystalline case extension of Chenot et al. model