Thermoformable fiberboards of wood pulp and nanofibrillated cellulose

Highly filled composites of poly (methyl methacrylate) (PMMA) and cellulose fibers with 25–75 wt. % cellulosic filler content were prepared by a flocculation/coagulation process of a mixture of a cellulose fiber suspension and PMMA emulsion. Two types of cellulose fibers, namely never dried bleached Kraft eucalyptus wood pulp and nanofibrillated cellulose were used. The process was induced by the addition of a salt containing trivalent ions (Al 3 + ) and enabled the preparation of a very homogeneous composite and an easy water separation by decantation and filtration (approx. 80 % water removal) during the formation of boards. The panels were hot pressed at 160 °C in 2–3 mm thick plates and characterized by mechanical tensile tests, scanning electron microscopy, and dynamic mechanical analysis. The produced fiberboards can be thermoformed into more complex shapes for applications in automotive areas and as furniture and architectural panels. • Novel method of preparation of composites with cellulose fibers all-in-water medium. • Composites with high concentrations of cellulose fibers, 25–75 wt. % of fibers. • Use of poly (methyl methacrylate) nanoemulsion as matrix. • Co-precipitation method with a good distribution of fibers in the acrylic matrix. • Increased stiffness by more than 100 % for composites with 50 and 75 wt. % NFC.