Spray-Drying Cellulose Nanofibrils: Effect of Drying Process Parameters on Particle Morphology and Size Distribution


  • Yucheng Peng
  • Yousoo Han
  • Douglas J. Gardner


Nanocellulose, spray-drying, particle morphology, particle size distribution


Spray-drying was chosen as an appropriately scalable manufacturing method to dry cellulose nanofibril (CNF) suspensions. Spray-drying of two different types of CNF suspensions—nanofibrillated cellulose (NFC) and cellulose nanocrystals (CNC)—was carried out using a laboratory-scale spray dryer. Effects of three spray-drying process parameters on particle morphology and particle size distribution were evaluated: 1) gas flow rate; 2) liquid feed rate; and 3) suspension solids concentration. Particle morphology was characterized by scanning electron microscopy (SEM) and a morphology analyzer. SEM showed that spray-drying of NFC formed fibrous particles and fibrous agglomerates, whereas spray-drying CNCs produced spherical and mushroom cap (or donut)-shaped particles. Particle morphology formation mechanisms are proposed for spray-drying nanocellulose suspensions. The effect of the three spray-drying process parameters on particle size distribution depended on the drying nature of the materials. The three parameters interacted to significantly affect particle size of CNC suspensions, whereas they did not interact to affect particle size of NFC suspensions. For the CNC suspension, a higher gas flow rate produced smaller particle sizes. The gas flow rate did not affect particle size for NFC suspensions. The effect of liquid feed rate and solids concentration on CNF particle size was negligible in this study. The smallest mean circle equivalent diameters produced in this study were 3.95 μm for NFC and 3.64 μm for CNC.


Beecher JF (2007) Organic materials: Wood, trees and nanotechnology. Nat Nanotechnol 2:466-467.nBrinker CJ, Scherer GW (1990) Drying. Pages 453-513 in CJ Brinker and GW Scherer, eds. Sol-gel science: The physics and chemistry of sol-gel processing, 1st ed. Academic Press Limited, London, UK.nEichhorn SJ, Dufresne A, Aranguren M, Marcovich NE, Capadona JR, Rowan SJ, Weder C, Thielemans W, Roman M, Renneckar S, Gindl W, Veigel S, Keckes J, Yano H, Abe K, Nogi M, Nakagaito AN, Mangalam A, Simonsen J, Benight AS, Bismarck A, Berglund LA, Peijs T (2010) Review: Current international research into cellulose nanofibres and nanocomposites. J Mater Sci 45:1-33.nFarid M (2003) A new approach to modeling of single droplet drying. Chem Eng Sci 58(13):2985-2993.nGardner DJ, Oporto GS, Mills R, Samir MASA (2008) Adhesion and surface issues in cellulose and nanocellulose. J Adhes Sci Technol 22:545-567.nHabibi Y, Lucia LA, Rojas OJ (2010) Cellulose nanocrystals: Chemistry, self-assembly, and applications. Chem Rev 110:3479-3500.nHandscomb CS, Kraft M, Bayly AE (2009) A new model for the drying of droplets containing suspended solids. Chem Eng Sci 64:628-637.nHede PD, Bach P, Jensen AD (2008) Two-fluid spray atomization and pneumatic nozzles for fluid bed coating/agglomeration purposes: A review. Chem Eng Sci 63: 3821-3842.nHubbe MA, Rojas OJ, Lucia LA, Sain M (2008) Cellulosic nanocomposites: A review. Bioresources 3(3):929-980.nKim KY, Marshall WRJ (1971) Drop-size distributions from pneumatic atomizers. AIChE J 17(3):575-584.nKlemm D, Kramer F, Moritz S, Lindstrom T, Ankerfors M, Gray D, Dorris A (2011) Nanocelluloses: A new family of nature-based materials. Angew Chem Int Ed 50:5438-5466.nKumar R, Prasad KSL (1971) Studies on pneumatic atomization. Industrial and Engineering Chemistry Process Design and Development 10(3):357-365.nLane WR (1951) Shatter of drops in streams of air. Ind Eng Chem 43:1312-1317.nLefebvre AH (1989) Atomisation and sprays. Hemisphere Publishing Corporation, Washington, DC.nMoczo J, Pukanszky B (2008) Polymer micro and nanocomposites: Structure, interactions, properties. J Ind Eng Chem 14:535-563.nMoon RJ, Marini A, Nairn J, Simonsen J, Youngblood J (2011) Cellulose nanomaterials review: Structure, properties and nanocomposites. Chem Soc Rev 40:3941-3994.nMujumdar AS, Devahastin S (2000) Fundamental principles of drying. Pages 1-22 in S Devahastin, ed. Mujumdar's practical guide to industrial drying. Exergex Vorp., Montreal, Canada.nNandiyanto ABD, Okuyama K (2011) Progress in developing spray-drying methods for the production of controlled morphology particles: From the nanometer to submicrometer size ranges. Advanced Powder Technology 22:1-19.nNukiyama S, Tanasawa Y (1938) An experiment on the atomization of liquids by means of an air stream. Trans Soc Mech Engrs (Japan) 14(4):86-93.nPatel KC, Chen XD, Kar S (2005) The temperature uniformity during air drying of a colloidal liquid droplet. Drying Technol 23:2337-2367.nPeng Y, Gardner DJ, Han Y (2012) Drying cellulose nanofibrils: In search of a suitable method. Cellulose 19(1): 91-102.nRizkalla AA, Lefebvre AH (1975) The influence of air and liquid properties on airblast atomization. J Fluid Eng-T ASME 97(3):316-320.nScherer GW (1990) Theory of drying. J Am Ceram Soc 73:3-14.nSchick RJ (2006) Spray technology reference guide: Understanding drop size. Spray Analysis and Research Services, Spray Drying Systems Co. Wheaton, Illinois, USA. 35 pp.nSiqueira G, Bras J, Dufresne A (2010) Cellulosic bionano-composites: A review of preparation, properties and applications. Polymers 2:728-765.nSiro I, Plackett D (2010) Microfibrillated cellulose and new nanocomposite materials: A review. Cellulose 17: 459-494.nVehring R (2007) Pharmaceutical particle engineering via spray drying. Pharm Res 25(5):999-1022.nWalton DE, Mumford CJ (1999) Spray dried products—Characterization of particle morphology. Chem Eng Res Des 77(1):21-38.n






Research Contributions