Vincent Verney1,3, Haroutioun Askanian2,3, Sophie Commereuc2,3 (1) Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND, FRANCE (2) Université Clermont Auvergne, ENSCCF, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND, FRANCE (3) CNRS, UMR 6296, ICCF, F-63171 AUBIERE, FRANCE Abstract: Usually organic polymers have a high hydrophobic character while vegetal fibres have a high hydrophilic one. Thus, the resulting marriage is a poor interfacial adherence due to poor compatibility between the matrix and the filler. Then low mechanical properties are obtained. A challenge is then in the improvement of the characteristic of the interface. Different ways can be used playing either onto the matrix as well as onto the filler. Different examples will be shown using Polylactic(acid), Polybutylene adipate terephthalate (PBAT) or Polyolefins (PP, HdPE) and (pine or cocoa nut shells) wood flour torrefied or not, or having been chemically extracted or not. We shall exemplify that the optimization of the interface between the matrix and the filler is a key parameter to process (bio)composites with a high level of mechanical properties and a controlled lifetime durability.