the present invention relates to a process for the manufacture of composite materials having lignocellulosic fibres dispersed in a thermoplastic matrix , while generally maintaining an average fibre length not below 0 . 2 mm . the process comprises defibrillation of the lignocellulosic fibres using a mixer and at a temperature less than the decomposition temperature of the fibres in order to separate the fibres and generate microfibres , crofêbres , followed by dispersion of the fibres in the thermoplastic matrix by mechanical mixing to get the moldable thermoplastic composition , followed by injection , compression , extrusion or compression injection molding of said composition . the process produces high performance composite materials having a tensile strength not less than about 55 mpa , a flexural strength not less than about 80 mpa , a stiffness not less than about 2 gpa , notched impact strength not less than about 20 j / m , and un - notched impact strength not less than about 100 j / m . the composite materials of the present invention are well - suited for use in automotive , aerospace , electronic , furniture , sports articles , upholstery and other structural applications .