Wood fibre reinforced composites

The two estimates, if plotted, look as shown in Fig. 6.4. This explains why fibre-reinforced composites like wood and GFRP are so stiff along the reinforced direction (the upper line of the figure) and yet so floppy at right angles to the direction of reinforcement (the lower line), that is, it explains their anisotropy. Anisotropy is sometimes what you want - as in the shaft of a squash racquet or a vaulting pole. Sometimes it is not, and then the layers of fibres can be laminated in a criss-cross way, as they are in the body shell of a Formula 1 racing car. 

J.-R. Schauder. Exxelor coupling agents for wood fibers reinforced composites. In Wood fibre Polymer Composites Symposium. Application and Trends, Bordeaux, France, March 27-28, 2003. 

Xu, X., Jayaraman, K., Morin, C., and Pecqueux, N. (2008) Life cycle assessment of wood-fibre-reinforced polypropylene composites. J. Mater. Process. Technol., 198 (1-3), 168-177. 

Fabrics made of glass or carbon fibres may also be used to make fibre reinforced composites on site. Normally a layer of adhesive is applied to the timber surface, one or more layers of the fabric are then pressed into the adhesive and a new layer of adhesive is applied to it, resulting, after cure, in a fibre reinforced composite. The principal direction of the fabric is normally oriented parallel to the wood fibres to improve bending strength and stiffness. 

Natural fibres possess sufficient strength and stiffiiess but are difficult to use in load bearing applications by themselves because of their fibrous structure. Most plastics themselves are not suitable for load bearing applications due to their lack of sufficient strength, stiffness and dimensional stability [51]. In natural fibre reinforced composites, the fibres serve as reinforcement by giving strength and stiffness to the structure while the plastic matrix serve as the adhesive to hold the fibres in place so that suitable structural components can be made. The matrix for the natural fibres includes thermosets, thermoplastics and mbber. Different plant fibres and wood fibres are fotmd to be interesting reinforcements for rubber, thermoplastics and thermosets [52-58]. 

A. Hassan, A. A. Salema, EH. Ani, and A.A. Bakar, A review on oil palm empty fruit bunch fiber-reinforced polymer composite materials. Polym. Compos. 31,2079-2101 (2010). R.R. Franck (Ed.), Bast and Other Plant Fibres, p. 397, CRC Press, Boca Raton, FL (2005. A.K. Bledzki, V.E. Sperber, and O. Faruk, Natural and wood fibre reinforcement in polymers, in Rapra Review Reports, Volume 13, pp. 1-144, iSmithers Rapra Publishing (2002). C. Baillie (Ed.), Green Composites Polymer Composites and the Environment, p. 308, Woodhead Publishing Limited, Cambridge, UK (2004). 

UPE resins can be used as clear castings or in combination with particulate fillers or fibres. The resin was developed to meet the demand of lightweight materials in military application. The first functional use of UPE was in radome. Because of the obvious advantages of easy processability and low cost, it was used in a wide range of applications in civil sectors such as tanks, pipes, and electronic gears. Some of the important products based on cast UPE resins are encapsulation of electronic assembly, buttons, door handles, knives, umbrellas, industrial wood and furniture finishing. A filled resin system using limestone, silica, and china clay are used for floor tiles. The major use of UPE is as a matrix for fibre-reinforced composites. Such composites have wide applications in automobile and construction industries such as boats, water-skis and television antennae. Examples of applications of UPE resins are presented in Table 2.7. 

Bonds (plus a gap-filler), fibre-reinforced composites, plus wood, steel, aluminium and concrete. Available for use with 3 different hardener systems, 273, 275 and 277 offering different gel and cure time. Dual cartridge system eliminates measuring and mixing. Colour change denotes full cure. 

The ability to join dissimilar materials De Bruyne originally had in mind the use of adhesives to join combinations of metal, wood and Gordon Aerolite. However, it is just as valid today when considering the structural bonding of the range of fibre reinforced composites that are now used in... 

Beg, M.D.H., Pickering, K.L. Accelerated weathering of unbleached and bleached kraft wood fibre reinforced polypropylene composites. Polym. Degrad. Stab. 93, 1939-1946 (2008)... 

W.R. Sharman and B.P. Vautier, Accelerated durability testing of autoclaved wood-fibre reinforced cement-sheet composites . Durability of Budding Mater. 3, 1986,... 

R.S.P. Coutts and M.D. Campbell, Coupling agents in wood fibre reinforced cement composites . Composites. 10,1979, 228 232. 

Chtourou, H., Riedl, B. and Ait-Kadi, A. (1992). Reinforcement of recycled polyolefins with wood fibres. Journal of Reinforced Plastic and Composites, 11, 372-394. 

Traditional processes can be modified to better industrialize the manufacturing of medium- or short-run manufacturing. In the thermoplastic composite field, the Pressure Diaphorm Process allows the processing of continuous fibre reinforced thermoplastics with low pressures. The press and the moulds (wood, composite or aluminium) can be about 70% cheaper. The process is convenient for short and medium runs in the range of 1000 up to 100000 parts. 

Riedel, U. (1999). Natural fibre-reinforced biopolymers as construction materials-new discoveries. 2nd International Wood and Natural Fibre Composites Symposium, June 28-29, Kassel/Germany, 1-10. 

Vegetable fibres (including wood fibres) represent a good replacement solution for glass and carbon fibres for the reinforcement of composites based on a thermoplastic matrix. The advantages of vegetable fibres are economically and ecologically important ... 

It is almost paradoxical that in the history of mankind composite materials were earlier used than their "homogeneous" rivals. The earliest "engineering materials" were bone, wood and clay. Wood is a composite of matrix lignin and a cellulosic reinforcement bone is a natural composite where fibres of hydroxyapatite reinforce the collagen matrix and the oldest building material was adobe clay as a matrix, reinforced by vegetable fibres. After the industrial revolution other composites were added reinforced rubber, reinforced concrete, reinforced asphalt, etc. 

Traditional composite panels are made from veneers and from mat-formed eomposites bonded by adhesive. More recently wood has also been combined (eompression moulded or extruded) with synthetic polymers, e.g. thermoplastic polymers, to make wood-polymer composites (WPC). WPC products have been growing very rapidly in the recent years, especially in the deeking market, where Woleott (2004) observed that their market share has grown from 2% in 1997 to 14% in 2003. Further, much research work has explored the use of fibre-reinforced polymers (FRP) to enhance the structural performance of engineered wood eomposites, ealled FRP-wood hybrid composites (Dagher et ai, 1998 Shi, 2002). 

Shi SQ (2001) Chapter 11 Fibre reinforced polymer (FRP) - wood hybrid composites. In Williamson TE (ed), APA Handbook on Engineered Wood. McGraw-Hill, New York Shukla NK, Rajput SS, Lai M, and Khanduri AK (1994) Studies on the variation of density and strength properties from pith to periphery in Populus deltoides. Journal of Indian Academy of Wood Science, 2(2) 1-6 Siau JF (1984) Transport processes in wood. Springer-Verlag, Berlin... 

This chapter first gives an overview of cellulose raw materials and their molecular and supermolecular structures. The principles of shaping cellulose into fibres, films, and nonwovens by means of solution techniques are then outlined followed by a section on properties and market applications of these materials. Derivatives of cellulose are presented with special emphasis on thermoplastic cellulose esters, typical plasticizers, and promising reinforcing materials. Finally, recent developments and future prospects of cellulose materials are reviewed as far as the above applications are concerned. This book does not cover the important applications of cellulose and ligno cellulose fibres for reinforcing thermoplastics, like wood plastic composites (WPC) and natural fibre reinforced plastics (NFRP), since in these cases cellulose does not substitute a thermoplastic. 

Rubber from trees has been used in both solid and latex form, and also converted further into isomerized and chlorinated polymers of very different properties and uses. Wood from trees is used directly for plywood, composition board, and wood-flour reinforcement of phenolic resins. The cellulose from wood is purified and used for laminates and for regenerated cellulose products such as cellophane, viscose rayon, and vulcanized fibre. The lignin from wood has been explored for use in plastics, but never carried through to complete commercial success. 

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