Processing cotton seed into biodegradable materials for agriculture as an alternative to synthetic polymers in Latin Amercia : Final report. INCO-DEV : International Scientific Cooperation Projects (1998-2002)

Like most European countries, Brazil and Argentina are faced with environmental management problems. Biodegradable materials could be a suitable alternative to replace advantageously petroleum based products in agriculture. Cottonseed proteins have good film forming properties. Cottonseed derivatives such as kernels and cakes, that contain great protein content, should have potential for making biodegradable materials. The main objective of the project: was to develop, at pilot or industrial scale, seed coatings, films and composites materials, made from raw cotton seed derivatives (kernels and cakes) and plant fibres. This project focused: on two types of processing technologies: wet processes (casting, laminating, seed coating, spread coating and fabrication of composites with plant fibres) and low moisture technologies (extrusion, thermomoulding). In particular, the following activities were undertaken: - Physical and chemical characterization of raw cottonseed derivatives; - Fabrication, from cottonseed derivatives, of optimized film-forming solutions that can be used for seed coating, spread coating, casting and composite material processing; - Study of the rheological properties and thermo-mechanical behaviour of cottonseed derivatives; - Study of the film-forming and adhesive cottonseed protein properties; - Study of the diffusion of pesticides entraps in a cottonseed protein based film; - Fabrication of materials at industrial or industrial pilot scale; - Characterization of material properties; - Economic study. Results and outcome: The processing parameters to extract cottonseed protein, in order to make a film forming solution, were optimized. This film forming solution was characterized and its properties (film-forming, stability, viscosity) adjusted to be employed for seed coating, film and composite technologies. The nutritional value of the solid by-product of the film-forming solution preparation established the possibility to use this by-product for animal feeding. The technical feasibility of manufacturing biodegradable materials from cotton seeds using low moisture and some of wet technologies (spray coating technology, seed coatings) has been demonstrated, at pilot industrial scale, for the first time. Concerning low moisture technologies, cotton seed processing must combine temperature and pressure to ensure protein conformation changes and good homogeneity of films. Within this framework, injection moulding seems to be an adapted technique. In the case of extrusion, the cohesion of matter is relatively poor and partners suggest mixing plasticized cakes or flours with synthetic biopolymers like PCL. For seed coating technologies, in spite of promising results concerning the pesticide release from the studied films, more industrial development is required to develop an "active seed coating" with adjustable release properties. A film coating for the commodity film coating market can be produced technically but is not yet competitive. The cohesion between different sorts of fibers and a cotton protein matrix was deeply studied. The best composites obtained are 5 to 10 fold more resistant than films without fibers. More research is required to produce these materials at industrial scale. The most competitive way, today, to produce biodegradable material from cottonseed derivatives is to use flours, with low lipid and shell content, processed by thermo moulding or injection to produce solid pieces. Further investigations must be carried out in close collaboration with companies interested in these products in order to improve the mechanical properties with regard to applications of materials for a targeted market. The current market for biodegradable polymers for films and bags, in Brazil and Argentina, would represent 22 000 t and 50 000 t respectively. The production of cotton in these countries makes it possible to answer these markets.

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Bibliographic Details
Main Author: Marquié, Catherine (ed.)
Other Authors: Do Amaral Sobral, Paulo José
Format: monograph biblioteca
Language:eng
Published: CIRAD-CA
Subjects:Q60 - Traitement des produits agricoles non alimentaires, graine de coton, biopolymère, traitement, http://aims.fao.org/aos/agrovoc/c_25473, http://aims.fao.org/aos/agrovoc/c_27468, http://aims.fao.org/aos/agrovoc/c_6195, http://aims.fao.org/aos/agrovoc/c_4221,
Online Access:http://agritrop.cirad.fr/530893/
http://agritrop.cirad.fr/530893/1/ID530893.pdf
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