Search results for "Chanvre"
showing 6 items of 6 documents
Contribution to the development of 100% bio-based composites : synthesis of bio-based polyepoxides, supercritical CO2 treatment of hemp fibers and im…
2018
This thesis contributes to the development of 100% bio-based hemp/epoxy composites. Current environmental issues favor the emergence of materials derived from renewable resources such as plant fibres and a wide range of bio-based building-blocks, source of epoxy prepolymers in particular. An intensive investigation of the two constituents (hemp fibres and polyepoxidic matrix) is carried out before the composites manufacturing. Supercritical CO2 treatment is applied to hemp fibres used as reinforcement in composite materials. This treatment, not optimized, leads to better individualization as well as a decrease in the hygroscopic power of the fibres. These aspects, which are essential in ord…
Development and characterization of a bio-based epoxy matrix for high-grade bio-based composites
2019
This study aims to develop 100% bio-based hemp/epoxy composites for semi-structural and structural applications. The thermal and mechanical performances of a 100% bio-based matrix derived from biomassare evaluated and reveal properties in the same order of magnitude as those obtained for polyepoxides based on DGEBA, that means a glass transition temperature of approximately 150°C and mechanical properties in the order of 120MPa for the maximum stress and 3.2 GPa for the tangent apparent modulus. This natural origin matrix is then used for the manufacture of composites reinforced with hemp rovings. The bending properties of these 100% bio-based materials are equivalent to those determined fo…
Development and characterization of a bio-based epoxy matrix for high-grade bio-based composites
2019
This study aims to develop 100% bio-based hemp/epoxy composites for semi-structural and structural applications. The thermal and mechanical performances of a 100% bio-based matrix derived from biomassare evaluated and reveal properties in the same order of magnitude as those obtained for polyepoxides based on DGEBA, that means a glass transition temperature of approximately 150°C and mechanical properties in the order of 120MPa for the maximum stress and 3.2 GPa for the tangent apparent modulus. This natural origin matrix is then used for the manufacture of composites reinforced with hemp rovings. The bending properties of these 100% bio-based materials are equivalent to those determined fo…
First archaeobotanical mentions of hemp leaved nettle ( Urtica cannabina ), in association with hemp ( Cannabis sativa ), on two sites in Champagne
2021
La culture du chanvre (Cannabis sativa) semble maintenant bien renseignée à partir du Xe siècle de notre ère en France septentrionale (Boulen et Zech-Matterne 2012), et l’utilisation des orties pour leurs fibres, généralement l’ortie dioïque (Urtica dioica), est également avérée. Toutefois, l’ortie à feuille de chanvre (Urtica cannabina) n’avait encore jamais été mentionnée parmi les études bioarchéologiques (pollen et macrorestes). Cette espèce a cependant été découverte pour la première fois à l’occasion d’une étude palynologique dans un contexte daté du XIVe siècle du site de Bezannes « le Village » (51), fouillé en 2013 (Gucker et al., en cours). Une fouille très récente à Troyes « Plan…
effect of the extraction of proteins from hemp press-cakes on their functionalities
2019
Plant proteins are a coherent option to feed the planet while limiting global warming. Common proteins (wheat, soya and maize) will soon no longer be sufficient to meet the increased demand for proteins. This thesis focuses on the development of a new source of plant protein for human consumption, based on a co-product of the oil mill: hemp proteins from press-cake. To meet this objective, the three main lines of action are: the definition of extraction conditions, the study of the physico-chemical properties of the isolates extracted under the defined conditions and the study of their emulsifying properties. The data in the literature on the extraction of hemp proteins are limited and not …
Différences de capacités d’induction de la germination de deux pathovars d’orobanche rameuse sur une gamme d’hôtes des familles des brassicacées et f…
2016
Branched broomrape (Phelipanche ramosa (L.) Pomel) is a holoparasite weed causing significant yield losses on several crops, especially in France on winter oilseed rape fields. The ability to induce germination of seeds of branched broomrape, variable between host species, represent an important information to identify the status of weed species present in the crop (host or non-host). In this study, conducted in in vitro conditions, we focused on two botanical families and two dominant pathovars of branched broomrape in France. We show that the host species is the only important explanatory factor of seed germination rate, the latter being not affected by the pathovar. Among the species stu…