Abstract: An improved apparatus and process for the production of isocyanate derived fiber reinforced materials by reactive processing. The improved apparatus comprises a mixing apparatus containing a mixing chamber, means for the metered introduction of at least two liquid reactive chemical streams into the chamber, means for introduction of reinforcing fibers into the chamber, an outlet duct for conducting a liquid reaction mixture comprising reinforcing fibers from the mixing chamber, and at least five gas jets suitably arranged to promote the fluidization and improved mixing of the liquid reaction mixture with the reinforcing fibers as the liquid reaction mixture comprising reinforcing fibers emerges from the outlet tube. Also disclosed is an improved process for producing fiber reinforced composites by employing the apparatus, and composites prepared according to the improved process.