Application Potential of Nanocellulose in the

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1 Application Potential of Nanocellulose in the Wood Industry Stefan Veigel and Wolfgang Gindl-Altmutter, Bangor (UK) Institute of Wood Science and Technology Department of Material Sciences and Process Engineering BOKU University of Natural Resources and Life Sciences, Vienna, Austria

2 Where could nanocellulose be used in the wood industry? 2

3 Case study I: Adhesives Glulam Parallam Particleboard MDF Adhesive bonding is the key to wood composites and engineered wood products 3

4 Mechanical properties of adhesives and cell walls Nanoindentation Wood cell wall II GPa UF A certain degree of toughness is required for a high bond strength! MUF PRF PVAc pmdi PUR Wood cell wall 50 µm 200 µm 4

5 MFC-modified UF: Solid wood adhesive bonds Lap shear testing (EN 302-1) UF+CNF F Fracture energy testing F Bond line Load UF Load F Deformation F Crack opening displacement Solid wood UF (high molar ratio, highly condensed) 1 wt% CNF added: Up to 30% increase in spec. fracture energy Up to 20% increase in shear strength 5

6 MFC-modified UF-bonded particleboard and OSB Relative change in board properties through the addition of 1 wt% MFC 6

7 MFC-modified UF-bonded particleboard >20% adhesive saved; nano not necessary (?) Internal bond (MPa) 9% UF 7% UF Particleboard mill: t/yr ~ t UF saved at 300 /t using ~500 t LCP Emissions reduced MFC LCP-1 MCC LCP-2 MFC microfibrillated cellulose MCC microcrystalline cellulose LCP lignocellulosic particles 7

8 Case study II: Waterborne wood coatings Exterior applications Moisture protection Light protection Colouring and colour retention Physical protection Interior applications Design Haptics Light protection Physical protection

9 Waterborne wood coatings: Viscosity Cone/plate system Shear rate = 5 s -1 Solid content = 30.5% MFC Viscosity (Pas) NCC Optical micrograph of the coated wood surface 200µm % Nanocellulose Viscosity of a water-based varnish as a function of the nanocellulose content

10 Waterborne wood coatings: Optical properties Gloss level (GU) REF NCC-1% NCC-2% NCC-5% MFC-1% MFC-2% Type of cellulose filler Gloss level of nanocellulose-modified coatings on wood at different measuring angles

11 Waterborne wood coatings: Mechanical resistance Scratch resistance Abrasion resistance Evaluation class 2-C Test force (N) Evaluation class 4-D Number of cycles REF NCC-1% NCC-2% NCC-5% MFC-1% MFC-2% Type of cellulose filler 0 REF NCC-1% NCC-2% NCC-5% MFC-1% MFC-2% Type of cellulose filler Both tests were performed according to ÖNORM A and EN

12 Waterborne wood coatings: Coating films Preparation of free-standing coating films Characterisation in tensile tests Mechanical properties of coating films containing different amounts of MFC

13 Conclusions and outlook Adhesives: MFC improves the performance of UF-bonded composites Realistic perspective for saving up to 20% UF by adding small amounts of LCP Coatings: MFC/NCC addition results in a moderate improvement of waterborne coating mechanics (e.g. scratch resistance) Other routes probably more interesting: functionalised MFC, viscosity, stabilisation of additives, etc

14 Thank you for your attention!