1. NANOPAPER FROM ALMOND SHELL Biorefinery Process Group Department of Chemical and Environmental Engineering University of Basque Country Pza. Europa 1, 20018, San Sebastian, SPAIN Correspondence to: jalel.labidi@ehu.es May 8-9, Coimbra, Portugal Eduardo Robles, Iñaki Urruzola, Jalel Labidi

2. COST Action FP1105 May 8-9 Coimbra, Portugal  To obtain cellulose nanofibers from almond shell (Prunus dulcis) with two different methods.  To manufacture papers from the obtained nanofibers and to compare their mechanical properties. Objectives Nanopaper From Almond Shell. Eduardo Robles, Iñaki Urruzola, Jalel Labidi.

3. COST Action FP1105 May 8-9 Coimbra, Portugal Procedure Nanopaper From Almond Shell. Eduardo Robles, Iñaki Urruzola, Jalel Labidi. Pretreatment NaOH (1%) v/v alkaline solution T = 20 ºC t = 24 h Method 2 NaOH 7.5% v/v T = 60 ºC t = 24 h Method 1 Ethanol/water 60/40 v/v T = 130 ºC t = 90 min Bleaching NaOH + H 2 O 2 + DTPA + MgSO 4 T = 70 ºC t = 150 min Acetylation HNO 3 (1/3) w/w Acetic Acid (1/20) w/w T= boiling t = 30 min Hydrolysis H 2 SO 4 (8..5 mL /g) T = 45 ºC t = 60 min Homogenization 40 passes P = 800-1200 bar Hydrogel preparation Vacuum filtering 0.45 μ m nylon filter Hot pressing T = 100 ºC P = 185 bar t = 25 min

4. COST Action FP1105 May 8-9 Coimbra, Portugal Results Nanopaper From Almond Shell. Eduardo Robles, Iñaki Urruzola, Jalel Labidi. Load (N) Tensile Stress (MPa) Strain (%) Modulus (GPa) Micropaper-9.51.52 Method 124.065.14.25.3 Method 224.262.72.95.6 Particular characteristics in the deformation of the nanofibers and the interaction between the nanofibers in each kind of nanopaper are involved in the performance of the paper under tensile stress. When compared to data from regular micropaper, it can be seen that nanopapers definitely presented improved properties. Stress vs Strain

5. The low porosity is associated with the close- packing properties of materials with high crystallinity; considering that the crystallinity of cellulose nanofibers from almond shells was around 80% for both methods, the small amount of space between fibers prevents pore formation, thus improving mechanical properties COST Action FP1105 May 8-9 Coimbra, Portugal Results Nanopaper From Almond Shell. Eduardo Robles, Iñaki Urruzola, Jalel Labidi. Grammage (g/m 2 ) Crystallinity (%) Micropaper a 7869 Method 18678.2 Method 29479.8

6. COST Action FP1105 May 8-9 Coimbra, Portugal Conclusions Nanopaper From Almond Shell. Eduardo Robles, Iñaki Urruzola, Jalel Labidi.  Chemical methods for the removal of non-cellulosic components were effective, providing pulps with high α -cellulose content, acid hydrolysis increased the crystallinity.  The nanopapers obtained in this study were flexible and translucent and exhibited improved mechanical properties compared to micropaper, but still not better than nanopaper made from other raw material. NaOH 7.5% represents a very effective delignification process to eliminate non-cellulosic components. The nanopaper obtained by this method presented slightly better mechanical properties than the nanopaper from organosolv.

7. COST Action FP1105 May 8-9 Coimbra, Portugal References Nanopaper From Almond Shell. Eduardo Robles, Iñaki Urruzola, Jalel Labidi. Urruzola I, Robles E, Serrano L, Labidi J, Nanopaper from almond (Prunus dulcis) Shell, Cellulose (2014) (In press) Henriksson M, Berglund LA, Isaksson P, Lindström T, Nishino T, Cellulose nanopaper structures of high toughness, Biomacromolecules 9 (2008) 1579–1585. Pirayesh, H., Khazaeian, A. (2012) Using almond (Prunus amygdalus L.) shell as a bio-waste ability in Wood based composite, Composites: Part B 43 1475–1479. Sehaqui H, Liu A, Zhou Q., Berglund L.A, Fast preparation procedure for large, flat cellulose and cellulose/inorganic nanopaper structures, Biomacromolecules 11(2010) 2195–2198. Serrano L, Urruzola I, Nemeth D, Belafi-Bako K, Labidi J, Modified cellulose microfibrils as benzene adsorbent, Desalination 270 (2011) 143-150. Yousefi H, Hejazi S, Mousavi M, Azusa Y, Heidari AH, Comparative study of paper and nanopaper properties prepared from bacterial cellulose nanofibers and fibers/ground cellulose nanofibers of canola straw, Industrial Crops and Products 43 (2013) 732– 737

8. Author would also like to thank to CONACyT, Mexico for support provided through Scholarship 216178. THANK YOU! COST Action FP1105 May 8-9 Coimbra, Portugal Nanopaper From Almond Shell. Eduardo Robles, Iñaki Urruzola, Jalel Labidi.