This thesis focuses on the treatment of wood flour used as reinforcement for polymer matrix composites. Indeed, the lack of compatibility between the hydrophilic wood and the hydrophobic polymers is the major difficulty encountered when processing wood-polymer composites. The treatment of the wood reinforcements is necessary to improve the mechanical and hygroscopic properties of the composites. Here, we proposed to apply direct fluorination to wood flour in order to reduce its hydrophilic character and then improve its compatibility with polymer matrix. Physicochemical characterization of the non-treated and fluorinated wood flours was carried out to observe the fluorination effects. The success of the fluorine grafting onto the wood components was confirmed by chemical analyses. Moreover, significant decrease in the number of moisture adsorption sites in wood was observed. This reduction led to a decrease in the equilibrium moisture content of wood after direct fluorination. In addition, the physical structure of the particles and the thermal behaviour of the wood were not modified by the treatment. Wood-polyester composites were processed by hot compression moulding with non-treated and fluorinated reinforcements. These composites were characterized by tensile, flexural and creep tests. Furthermore, a hygroscopic characterisation was also carried out. The results showed an improvement of the mechanical and hygroscopic properties of the composites with the reinforcements fluorination.
Influence of physico-chemical treatments of the reinforcements on the mechanical behaviour of wood-polymer composites