TEAM: Jaakko Pere, Vesa Kunnari, (VTT) Heidi Turunen (Aalto University)
Background
Wood based cellulose is the largest cellulose source on earth, and it has been used in paper and board manufacturing dating back for even centuries. Cellulose micro/nanofibrils (CNF) can be liberated from various plant fibers using mechanical forces, chemical treatment, enzymes or combinations of these. The most typical mechanical methods include homogenization, microfluidization, microgrinding or cryocrushing. After fibrillation the width of micro/nanofibrils is typically between 5 to 20 nm and length several micrometers. Micro/nanofibrils have inherent binding ability to wood and also to various small scale particles such as color pigments. These features have been combined by applying color on wood surface using only nanocellulose as binder.
Characteristics
Cellulose nanofibrils have different characteristics depending on the fibre origin and processing method. Appearance as dried layer may vary optically from completely transparent to translucent. Micro/nanofibrils can be easily dyed for visual effects. Films and structures made from nanofibrils in general have comparable tensile strength to aluminium although the surface appearance is paper-like. These are also completely recyclable. Micro/nanofibril paint can be washed away from surfaces using water. Using nanofibril manufacturing technology developed at VTT the paint application solids is between 10…15% and drying time comparable with traditional water based paints.
Potential Applications
Micro/nanofibril coating as paint may provide as interior decoration a new eco-friendly option for surface treatment. Non-permanent markings that are removed using water spray and cloth e.g in construction, stencils, temporary protection during transport or dressing paint could apply the technology. Technology will be developed further to provide enhanced water tolerance.
