All Natural High-Density Fiber- and Particleboards from Hemp Fibers or Rice Husk Particles

In the present study, long hemp fibers and rice husk particles have been used for producing all natural-based boards for building, automotive and in-door furniture, employing a simple and economic transformation process (namely, compression molding). In order to have the required consistence and mechanical strength, cornstarch was employed as binder. By this way, fiber- and particleboards have been prepared and characterized in terms of morphology, mechanical properties (flexural modulus and strength). The influence of different relative humidity levels on composite storage modulus and heat deflection temperatures has been investigated, as well. Long fibers turned out to be capable of sustaining approximately three times the load with respect to particles in standard conditions. Thermal, hygro- and photo stability of the above materials have been investigated under three ageing conditions: namely, (i) high temperature (thermal ageing), (ii) humidity plus high temperature (hygro-thermal ageing) and (iii) UV radiations (photo ageing). Regardless of the experimental ageing conditions adopted, fiberboards have shown good mechanical stability with a modest decrease of storage modulus (<20%) with respect to the values before exposure.