Properties of hemp fibre polymer composites / Anders Thygesen / Roskilde [Denmark] : Risø National Laboratory (2006)  

Titre : Properties of hemp fibre polymer composites : An optimisation of fibre properties using novel defibration methods and fibre characterisation Type de document : texte imprimé Auteurs : Anders Thygesen, Auteur ; Université du Danemark (Roskilde), Organisme de soutenance Editeur : Roskilde [Denmark] : Risø National Laboratory Année de publication : 2006 Importance : 146 p. Présentation : ill. Format : 30 cm ISBN/ISSN/EAN : 978-87-550-3440-2 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Chanvre et constituants Le chanvre ou chanvrier (Cannabis sativa L.) est la seule espèce du genre botanique Cannabis. Ce terme latin est souvent utilisé aussi comme nom vernaculaire pour distinguer les variétés de chanvre cultivé à usage industriel des variétés de cannabis à usage récréatif ou médical. C'est une espèce de plante annuelle, de la famille des Cannabaceae. La graine de chanvre s'appelle le chènevis. Composites à fibres végétales Défibrage Thèses et écrits académiques Index. décimale : 668.4 Plastiques, vinyles Résumé : Caractérisation of hemp fibres was carried out with fibres obtained with low handling damage and defibration damage to get an indication of how strong cellulose based fibres that can be produced from hemp. Comparison was made with hemp yarn produced under traditional conditions where damage is unavoidable. The mild defibration was performed by degradation of the pectin and lignin rich middle lamellae around the fibres by cultivation of the mutated white rot fungus Phlebia radiata Cel 26. Fibres with a cellulose content of 78% w/w could thereby be produced which is similar to the cellulose content obtained by steam explosion of hemp fibres prior defibrated with pectin degrading enzymes. The S2 layer in the fibre wall of the hemp fibres consisted of 1-4 cellulose rich and lignin poor concentric layers constructed of ca. 100 nm thick lamellae. The microfibril angle showed values in the range 0-10° for the main part of the S2-layer and 70-90° for the S1-layer. The microfibrils that are mainly paralle l with the fibre axis explain the high fibre stiffness, which in de fibrated hemp fibres reached 94 GPa. The defibrated hemp fibres had higher fibre stiffness (88-94 GPa) than hemp yarn (60 GPa), which the fibre twisting in hemp yarn explains. The hemp fibre stiffness appeared to increase linearly with cellulose content and crystallinity and to decrease with cellulose twisting angle. Pure crystalline cellulose had an estimated stiffness of 125 GPa. The defibration with P. radiata Cel 26 resulted in fibre strength of 643 MPa, which is similar to the strength of traditionally produced hemp yarn (677 MPa) even though mild processing was applied. The plant fibre strength seemed therefore to be linearly dependent on the cellulose content and not clearly dependent on the introduced physical damage during handling and defibration. Pure cellulose appeared to have effective strength of 850 MPa that is about 10% of the strength on the molecular level. Thèse : Thèse : Université du Danemark : 2006 En ligne : https://backend.orbit.dtu.dk/ws/portalfiles/portal/88454002/ris_phd_11.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18576

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
15097	TH/2006/THY	Thèse, mémoire, etc...	Bibliothèque principale	Documentaires	Disponible

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