High Performance Nano-Cellulose Composites

Transparent Composites for Defense Applications

Synopsis:

• Cellulose nano-crystals (CNC) and cellulose nano-fibrils (CNF) provide strength properties equivalent to Kevlar and can be used in optically clear applications like composite windshields.
• The Forest Products Laboratory is supporting a project at the Army Research Laboratory in Aberdeen, MD, to produce and evaluate primarily clear composites as reinforced glass.

Overview: The Forest Products Laboratory (FPL) has been working for three years on producing cellulose nanocrystals and the strongest and optically clearest versions of cellulose nano-fibrils. In 2009, FPL was approached by the Army Research Laboratory to help with a project producing optically clear composites. Because of the needs for larger amounts of materials, FPL began a scale-up project to produce both CNC and CNF at kilogram scales. FS Research provided additional funds for the pilot equipment needed to increase the process scale to about 20 kg. The Army Research Laboratory has been blending CNC and CNF in various resins, focusing on polymethyl methacrylate (PMMA) as the initial base resin because it provides optically clear panels and films and can be solvent cast. They have succeeded in incorporating CNC in electro-spun PMMA nano-fibers at 40 weight percent CNC. The electro-spinning process aligns the CNC in the fiber and maintains the dispersion. This enables researchers to laminate sheets with extra PMMA, producing composite sheets. Final sheets contained 1 weight percent CNC and maintained optical clarity.