Project: Green composites and 3D objects

Green Building is a movement gained global attention over the past few years. Planned to be environmentally responsible, economically viable and healthy places to live and work, the target now is to achieve 10% of basic chemical building blocks arising from plant derived renewable sources by 2020, with development concepts in place by then to achieve a further increase to 50% by 2050. As biocomposites presents many advantages such as lower weight and manufacturing costs, different parts are now interested in using them in green buildings. Eco-friendly bio-composites from plant-derived fiber (natural/biofiber) and crop-derived plastics (bio-plastic) are novel materials and would be of great importance as a solution to both growing environmental threat and the uncertainty of petroleum supply. _x000D_The forest-based industries are the largest forest-based raw material consumers in Europe. These industries are now facing a number of challenges, COly regarding the access to raw materials. The developments in wood-based bio-energy production and its increased growth demand is expected to press the forest based industry over the next years COly due to the foreseen increase of the feedstock costs for wood products, such as sawdust and wood residues, common raw materials for the production of wood-based panels. This drives towards the need for finding effective raw materials, alternative to wood, for the manufacturing of biocomposites._x000D_To date, various other lignocellulosic materials from agricultural wastes have been tested regarding this aim. The utilization of raw materials from annual plants is interesting since these are easily available, requiring low energy during production; they are renewable, cheap, showing carbon dioxide neutrality, contributing to the recycling of agricultural residues. Among the various fibre crops, hemp and kenaf seem to be the most promising resources for wood replacement. These plants give fibres, wood and seeds that after processing may be used in a number of industrial products. _x000D_In the framework of this project, 3D objects, particleboards and MDF panels will be manufactured from hemp and kenaf. The adhesives to be used will be synthesized from raw materials derived from natural resources. The target is to develop totally green products suitable for various applications. Especially the particleboards will present a range of densities suitable for various applications, such as heavy load bearing panels (thickest panels) to insulation panels (light panels). The panels suitable for interior application will have a variety of special properties (like thermal and acoustic impenetrability and fire retardation), either due to the inherent characteristics of hemp and kenaf (hollow tubular structure) or the addition of suitable chemicals in the resinous system. _x000D_In total two types of resinous systems will be synthesized. The first one will be based on biodegradable polymers, in particular plasticized chitosan and an aliphatic polyester, that will be used for the manufacturing of 3D objects by injection molding. Chitosan is a polysaccharide derived from chitin which is very abundant in nature, being found in fungal walls and exoskeletons of crustaceans and insects. In order to improve its processability it will be mixed with a natural plasticizer, glycerol. Addition of lipids, such as fatty acids and waxes, will be studied, in the hope of improving the water barrier property of the biopolymer. The aliphatic polymer used, poly(butylene succinate), will be prepared from renewable natural derived monomers, being completely biodegradable and biocompatible. Both these polymers, as well as various mixtures of both, to maximized their properties, will be melt mixed using an extruder with hemp and kenaf fibers at various concentrations. Thus, fiber reinforced composites will be prepared, ultimately replacing conventional composites. To address the CO problem of natural fiber/polymer composites, the incompatibility between the hydrophilic natural fibers and the hydrophobic thermoplastic matrices, the use of a compatibilizer in order to improve the adhesion between fiber and matrix will be examined as well as fiber surface treatment. _x000D_The other resinous system will utilize thermosetting tannin and lignin polymers that will be used for the production of particleboards and medium density fibreboards . In any case, the polymers will contain more than 80% of a naturally derived material that may be used as such or after treatmen/activation by other biobased/synthetic chemicals. The final adhesion system may contain petrochemical materials (additives, cross-linkers and hardeners) that enforce the requested properties for each application at a percentage lower than 20%. In the case of panels emphasis will be given to the use of additives that render fire resistance endorsement. The panels will have low formaldehyde emissions . The final products will be launched into the market in 2 years time._x000D__x000D_

Acronym GreenComposites (Reference Number: 6544)
Duration 01/01/2012 - 31/12/2014
Project Topic In this project, 3D objects, particleboards of various densities and MDF panels will be developed from hemp and kenaf bonded with green resins based on tannin, lignin and chitosan. The panels will be fire retardant, thermal and acoustic proof.
Project Results
(after finalisation)
The CO results of this this project on behalf of CHIMAR HELLAS SA are the development of lightweight particleboards and composites for biodegradedable 3D objects. _x000D_In particular, CHIMAR developed lightweight particleboards only from Hemp or kenaf and bio-based or totally natural adhesives. The natural raw-materials used for these resins were lignin, glyocalated lignin (GL), tannin and starch. The best performed bio-based resin was a Phenol-Formaldehyde (PF) resin with 50% phenol replacement by GL, followed by a natural resin system consisting of Tannin and hardener (at levels no higher than 12%). However, their adhesive performance was lower than that of a typical Phenol-Formaldehyde resin. The lightweight hemp or kenaf particleboards had densities as low as of 400 and 350 kg/m3, while a typical density of wood-based particleboards is about 600-700kg/m3. The newly developed lightweight panels perform internal bond values comparable to that of wood-based panels with higher density and have significantly lower formaldehyde content. Such hemp or kenaf particleboards are suitable for interior do-it-yourself applications like furniture, desks, coatings, etc. _x000D_IN et framework of this project, CHIMAR also prepared the required quantities of bio-based PF resins with phenol replacement up to 50% by lignin, glyoxalated lignin and tannin as well as the tannin natural adhesive system, for lab tests at Valbopan. Valbopan evaluated these resins in the production of MDF of 3 layers having hemp shives at core and wood fibers at the face layers. _x000D_Together, CHIMAR with the contribution of AUTH (subcontractor) developed composites suitable for the manufacturing of 3D objects. In particular, the composites were prepared from the biodegradable polymer poly(butylene succinate) (PBSu) while hemp or kenaf fibres and shives were used as reinforcing materials at levels up to 70%wt. Chitosan plasticized with glycerin was also evaluated as additive to PBSuat at the levels of 10 and 20% . All composites were prepared by the melt-mixing technique. These composites showed increased enzymatic and soil degrade ability but lower mechanical properties (especially the products with shives) compared with the neat PBSu polymer. However, the addition of Chitosan to PBSu/hemp composites at ratios of PBSu/Chitosan of 90/10 and 80/20, improved somewhat the mechanical properties but lowered the biodegradeability of composites. These results were justified by SEM, XRD, FTIR and thermal (TGA and DSC) studies. Such products are suitable for the manufacturing of pots for planting. _x000D_The products developed within the framework of this project are superior to the relative conventional ones available currently on the market within the context of their improved biodegradability, better mechanical properties and lower free formaldehyde content. The technology for producing such particleboards and composites for 3D objects is ready for introduction to the industry. However, the high price of hemp and kenaf material (shives or fibers) compared to wood, as well as their seasonal availability, impede their widespread application on regular industrial productions. _x000D_
Network Eurostars
Call Eurostars Cut-Off 6

Project partner

Number Name Role Country
3 CHIMAR HELLAS S.A. Coordinator Greece
3 Valbopan, Fibras de Madeira S.A. Partner Portugal
3 HempFlax Exploitatie BV Partner Netherlands