Lignocellulosic composites extrusion

Moreover, wood has limited thermoplasticity. Although it can be bent under steam and chemical treatment, wood normally bums before it melts or becomes sufficiently plastic for heat molding or extrusion. These two techniques are important ways of shaping materials in high-speed composite production and are therefore keys to the cost-efficient penetration of lignocellulosic materials into the composites market. Chemical modification of wood offers a means of improving its thermoplasticity. 

Extrusion and injection-moulding are the economically most attractive processing methods of thermoplastic-based composites. The extrusion press processing (express-processing) has been developed for the production of flax fibre reinforced PP at the research centre of Daimler Benz [7]. In this process, flax fibre non-wovens and PP melt films are alternatively deposited and moulded. A production process for PP semi-products reinforced with lignocellulosic fibres in the form of mats has been developed by BASF AG [7]. Fibre mats are produced by stitching together layers of fibres which have previously been crushed. 

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