Effect of lignin on the morphology and rheological properties of nanofibrillated cellulose produced from γ-valerolactone/water fractionation process
- 506 Downloads
The influence of lignin content on nanocellulosic fibril morphology, charge, colloidal stability and immobilization has been systematically investigated employing a series of nanofibrillated cellulose (NFC) with varying residual lignin content and compared to those of NFC made from fully bleached pulp. The lignin-containing pulps were obtained from the fractionation of Eucalyptus globulus wood chips in gamma-valerolactone (GVL)/water under the same conditions, they differ by the intensity of washing for lignin removal. The reference pulp originated from another cook of eucalyptus wood chips, and was fully bleached with a short Elemental-Chlorine-Free (ECF) sequence. All the pulps have a comparable hemicellulose-to-cellulose ratio and CED viscosity. NFC suspensions of 1 wt% concentration were mechanically produced from fluidization. The results indicated that the fibrils morphology, thickness and corresponding flocculation within NFC suspensions was highly influenced by the presence of lignin unevenly distributed on the fibril surface and within the suspension as particles. The presence of lignin in NFC suspension had a large impact on the rheology and dewatering of the NFC. Samples with high lignin content had distinguishable viscoelastic properties due to the greater flocculation of thicker fibrils and lower gel-like characteristics, with better dewatering properties.
KeywordsNanocellulose Lignin Dissolving pulp Rheology Gamma-valerolactone
Funding from Aalto University, School of Chemical Technology and Finnish Bioeconomy Cluster Oy (FIBIC) via the Advanced Cellulose to Novel Products (ACel) research program is gratefully acknowledged. This work made use of Aalto University Bioeconomy Facilities. The authors would like to thank Ms. Ritva Kivelä for her support with the NFC suspensions production, Dr. Kaarlo Nieminen for his support with the mathematical solutions, Ms. Rita Hataka for her support with the chromatographic analyses, Dr. Juan José Valle-Delgado for his advices on AFM image analysis, Dr. Krista Vajanto for her support on SEM images acquisition, Dr. Michael Hummel, Dr. Marc Borrega and Prof. Eero Kontturi for their advices on the manuscript.
- Conley K (2014) Annual review of global pulp and paper statistics. RISI Inc, PPIGoogle Scholar
- Dalpke B, Kerekes RJ (2005) The influence of fibre properties on the apparent yield stress of flocculated pulp suspensions. J Pulp Paper Sci 31:39–43Google Scholar
- Janardhnan S, Sain MM (2007) Isolation of cellulose microfibrils—an enzymatic approach. BioResources 1:176–188Google Scholar
- Janson J (1970) Calculation of the polysaccharide composition of wood and pulp. Pap Puu 52:323–329Google Scholar
- Nelson K, Retsina T, Iakovlev M, van Heiningen A, Deng Y, Shatkin JA, Mulyadi A (2016) American Process: Production of Low Cost Nanocellulose for Renewable, Advanced Materials Applications. In: Madsen LD, Svedberg EB (eds) Materials research for manufacturing: an industrial perspective of turning materials into new products. Springer International Publishing, Cham, pp 267–302CrossRefGoogle Scholar
- Pääkkö M, Ankerfors M, Kosonen H, Nykänen A, Ahola S, Österberg M, Ruokolainen J, Laine J, Larsson PT, Ikkala O, Lindström T (2007) Enzymatic hydrolysis combined with mechanical shearing and high-pressure homogenization for nanoscale cellulose fibrils and strong gels. Biomacromolecules 8:1934–1941. https://doi.org/10.1021/bm061215p CrossRefGoogle Scholar
- Pääkkönen T, Dimic-Misic K, Orelma H, Pönni R, Vuorinen T, Maloney T (2016) Effect of xylan in hardwood pulp on the reaction rate of TEMPO-mediated oxidation and the rheology of the final nanofibrillated cellulose gel. Cellulose 23:277–293. https://doi.org/10.1007/s10570-015-0824-7 CrossRefGoogle Scholar
- Rojo E, Peresin MS, Sampson WW, Hoeger IC, Vartiainen J, Laine J, Rojas OJ (2015) Comprehensive elucidation of the effect of residual lignin on the physical, barrier, mechanical and surface properties of nanocellulose films. Green Chem 17:1853–1866. https://doi.org/10.1039/C4GC02398F CrossRefGoogle Scholar
- Sandas SE, Salminen PJ, Eklund DE (1989) Measuring the water retention of coating colors. Tappi J 17:207–210Google Scholar
- Sjöström E (1993) Wood chemistry: fundamentals and applications. Academic Press, San DiegoGoogle Scholar
- Young R (2014) World dissolving pulp monitor. RISI Inc, PPIGoogle Scholar