Sustainable applications of natural fibers wastes in bio-architecture and organic agriculture

This work deals with the valorisation of natural fibres wastes from different sources, namely: -Poor quality wools from sheep farming (shearing and butchery) -Fibre by-products from industrial processing (carding, combing, spinning) -Used garments and -Technical Hemp fibres which are fibres from ripe hemp plants. We are used to think of wool as a fine, soft fibre suitable for manufacturing high quality, luxury garments. However, this is true for selected breedings, especially the fine merino wool, which represents less than 30% of the world annual clip, while most of the wool is coarser, especially that produced from sheep reared for meat production. The consumption of sheepmeat is increasing over the years, with as corresponding reduction of the wool production, and many farmers have been increasing switching from fibre to food crop production to meet growing demand for meat. Also in the EU, sheep farming is mostly involved in meat and milk production. The EU flock is about 100 000 M sheep and most of the wool is essentially perceived as a by-product that doesn't cover the cost of shearing. EU wool is generally coarse and highly contaminated by kemps and impurities .... Application other than spinning and weaving have been proposed in building, for thermal and acoustic insulation, but siting and installation is difficult and expensive. Moreover, wool fibres are stuck with synthetic polymers in order to obtain fluffy rolls. A method of improving the properties of wool-based insulation materials is processing wool in mid alkali media in order to obtain: ?Disruption of the fibre structure ?Tranformation (hydrolysis) of the wool protein into an adhesive glue to be used for sticking the residual fibres each other ?The result is a stronger and stiffer supermolecular structure of the residual material resulting in self-supporting, 100% wool boards. Addition of strong and stiff fibres as the Technical hemp fibres produced by fiberisation of industrial hemp stems, is a real way to improve the mechanical performances of the insulation panels (stiffness, tensile and bending moduli). Alkali treatment of technical hemp causes: ?Disruption of fibre bundles ?Swelling ?Hydrophilic increase ?Higher wet modulus When treating wool and hemp fibres blends in the same identical conditions, the wool protein glue stick the hemp fibres permanently in a very strong, excellent insulation material. Thermal performances are comparable to other fibrous insulating materials such as fiberglass and rock mineral wool, Sound absorption is very good at medium and high frequencies typical of acoustic fibrous materials (i.e. glass and rock mineral wool with the same density) Moreover, and this is a very important peculiarity, airborne formaldehyde (and maybe some other VOCs) responsible for Sick Building Syndrome may be reduced to less than the TLV limits provided by the World Health Organisation. Another ready available resource which represent a large fibrous biomass is rice straw. Traditional disposal methods are open-field burning or chopping and soil incorporation. Multi-year consecutive incorporation may cause soil detriment and development of methane. Even rice straw may be used to increase stiffness ow wool-based stiff boards. ?Rice straw swells in alkali ?Hydrophilicity increases ?Straw stem are stuck by the protein glue Once again, Thermal Conductivity & Sound absorption of the resulting fiberboards are good. Moreover, the fire resistance becames really strong because of the silica content of rice straw combined with the LOI of the wool. And, we have tried to give some aesthetic value to the panels for visible applications. Finally, all materials proposed are totally recyclable and compostable since they are made of keratin and cellulose. This means .... they can beconverted into organic fertilisers thorugh a simple and effective treatment with superheated water to produce: -liquid fertilisers for foliar feeding -solid powder and pellets for organic agriculture. The bureaucratic procedures for the inclusion of these fetilisers in the list of the Ministry of the Agricultural Policy is in progress.