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Cellulose

, Volume 20, Issue 4, pp 1657–1667 | Cite as

Modification of crystallinity and pore size distribution in coagulated cellulose films

  • Åsa ÖstlundEmail author
  • Alexander Idström
  • Carina Olsson
  • Per Tomas Larsson
  • Lars Nordstierna
Original Paper

Abstract

In this study the effects of altering the coagulation medium during regeneration of cellulose dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate, were investigated using solid-state NMR spectroscopy and NMR cryoporometry. In addition, the influence of drying procedure on the structure of regenerated cellulose was studied. Complete conversion of the starting material into regenerated cellulose was seen regardless of the choice of coagulation medium. Coagulation in water predominantly formed cellulose II, whereas coagulation in alcohols mainly generated non-crystalline structures. Subsequent drying of the regenerated cellulose films, induced hornification effects in the form of irreversible aggregation. This was indicated by solid-state NMR as an increase in signal intensity originating from crystalline structures accompanied by a decrease of signal intensity originating from cellulose surfaces. This phenomenon was observed for all used coagulants in this study, but to various degrees with regard to the polarity of the coagulant. From NMR cryoporometry, it was concluded that drying induced hornification generates an increase of nano-sized pores. A bimodal pore size distribution with pore radius maxima of a few nanometers was observed, and this pattern increased as a function of drying. Additionally, cyclic drying and rewetting generated a narrow monomodal pore size pattern. This study implies that the porosity and crystallinity of regenerated cellulose can be manipulated by the choice of drying condition.

Keywords

Crystallinity NMR cryoporometry Porosity Regenerated cellulose Solid-state NMR 

Abbreviations

CI

Crystallinity index

CP/MAS

Cross polarization magic angle spinning

EMIMAc

1-Ethyl-3-methylimidazolium acetate

EtOH

Ethanol

ND

Never dried

NMMO

N-methylmorpholine-N-oxide

NMR

Nuclear magnetic resonance

OD

Oven dried

PrOH

1-Propanol

PSD

Pore size distribution

RH

Relative humidity

Notes

Acknowledgments

This work has been carried out within the framework of Avancell—Centre for Fibre Engineering. Financial support from the Swedish Foundation, Södra Skogsägarnas stiftelse för forskning, utveckling och utbildning, and Chalmers Area of Advance Material Science are all gratefully acknowledged. The NMR measurements were carried out at the Swedish NMR Centre, Göteborg, Sweden. Dr. Derek Weightman at Sappi Saiccor in South Africa is kindly acknowledged for supplying samples of the eucalyptus dissolving pulp.

References

  1. Biganska O, Navard P (2005) Kinetics of precipitation of cellulose from cellulose−NMMO−water solutions. Biomacromolecules 6:1948–1953CrossRefGoogle Scholar
  2. Biganska O, Navard P (2009) Morphology of cellulose objects regenerated from cellulose–N-methylmorpholine N-oxide–water solutions. Cellulose 16:179–188CrossRefGoogle Scholar
  3. Boerstoel H, Maatman H, Westerink JB, Koenders BM (2001) Liquid crystalline solutions of cellulose in phosphoric acid. Polymer 42:7371–7379CrossRefGoogle Scholar
  4. Boissier C, Feidt F, Nordstierna L (2012) Study of pharmaceutical coatings by means of NMR cryoporometry and sem image analysis. J Pharm Sci 101:2512–2522CrossRefGoogle Scholar
  5. Cousins SK, Brown RM Jr (1995) Cellulose I microfibril assembly: computational molecular mechanics energy analysis favours bonding by van der Waals forces as the initial step in crystallization. Polymer 36:3885–3888CrossRefGoogle Scholar
  6. French AD, Miller DP, Aabloo A (1993) Miniature crystal models of cellulose polymorphs and other carbohydrates. Int J Biol Macromol 15:30–36CrossRefGoogle Scholar
  7. Ibbett RN, Domvoglou D, Fasching M (2007) Characterisation of the supramolecular structure of chemically and physically modified regenerated cellulosic fibres by means of high-resolution carbon-13 solid-state NMR. Polymer 48:1287–1296CrossRefGoogle Scholar
  8. Idström A, Brelid H, Nydén M, Nordstierna L (2013) CP/MAS 13C NMR study of pulp hornification using nanocrystalline cellulose as a model system. Carbohydr Polym 92:881–884CrossRefGoogle Scholar
  9. Isobe N, Kim U-J, Kimura S, Wada M, Kuga S (2011) Internal surface polarity of regenerated cellulose gel depends on the species used as coagulant. J Colloid Interface Sci 359:194–201CrossRefGoogle Scholar
  10. Isobe N, Kimura S, Wada M, Kuga S (2012) Mechanism of cellulose gelation from aqueous alkali-urea solution. Carbohydr Polym 89:1298–1300CrossRefGoogle Scholar
  11. Kotek R (2006) Regenerated cellulose fibers. In: Lewin M (ed) Handbook of fiber chemistry, 3rd edn. Taylor & Francis, CRC Press, New York, USA, pp 668–764Google Scholar
  12. Laity PR, Glover PM, Hay JN (2002) Composition and phase changes observed by magnetic resonance imaging during non-solvent induced coagulation of cellulose. Polymer 43:5827–5837CrossRefGoogle Scholar
  13. Laivins GV, Scallan AM (1993) The mechanism of hornification of wood pulps. In: Baker CF (ed) Products of papermaking, Trans 10th Fund Res Symp, Oxford, pp 1235–1260Google Scholar
  14. Larsson PT, Wickholm K, Iversen T (1997) A CP/MAS13C NMR investigation of molecular ordering in celluloses. Carbohydr Res 302:19–25CrossRefGoogle Scholar
  15. Lindman B, Karlström G, Stigsson L (2010) On the mechanism of dissolution of cellulose. J Mol Liq 156:76–81CrossRefGoogle Scholar
  16. Liu W, Budtova T (2012) Ionic liquid: a powerful solvent for homogeneous starch–cellulose mixing and making films with tuned morphology. Polymer 53:5779–5787CrossRefGoogle Scholar
  17. Liu H, Cheng G, Kent M, Stavila V, Simmons BA, Sale KL, Singh S (2012) Simulations reveal conformational changes of methylhydroxyl groups during dissolution of cellulose Iβ in ionic liquid 1-ethyl-3-methylimidazolium acetate. J Phys Chem B 116:8131–8138CrossRefGoogle Scholar
  18. Mori T, Chikayama E, Tsuboi Y et al (2012) Exploring the conformational space of amorphous cellulose using NMR chemical shifts. Carbohydr Polym 90:1197–1203CrossRefGoogle Scholar
  19. Newman RH (1998) Evidence for assignment of 13C NMR signals to cellulose crystallite surfaces in wood, pulp and isolated celluloses. Holzforsch 52:157–159CrossRefGoogle Scholar
  20. Newman RH (2004) Carbon-13 NMR evidence for co crystallization of cellulose as a mechanism for hornification of bleached kraft pulp. Cellulose 11:45–52CrossRefGoogle Scholar
  21. Newman RH, Davidson TC (2004) Molecular conformations at the cellulose–water interface. Cellulose 11(1):23–32CrossRefGoogle Scholar
  22. Nocanda X, Larsson PT, Spark A, Bush T, Olsson A, Madikane M, Bissessur A, Iversen T (2007) Cross polarisation/magic angle spinning 13C-NMR spectroscopic studies of cellulose structural changes in hardwood dissolving pulp process. Holzforsch 61:675–679Google Scholar
  23. Östlund Å, Köhnke T, Nordstierna L, Nydén M (2010) NMR cryoporometry to study the fiber wall structure and the effect of drying. Cellulose 17:321–328CrossRefGoogle Scholar
  24. O’Sullivan AC (1997) Cellulose: the structure slowly unravels. Cellulose 4:173–207CrossRefGoogle Scholar
  25. Park S, Johnson D, Ishizawa C, Parilla P, Davis M (2009) Measuring the crystallinity index of cellulose by solid state 13C nuclear magnetic resonance. Cellulose 16:641–647CrossRefGoogle Scholar
  26. Park S, Baker J, Himmel M, Parilla P, Johnson D (2010) Cellulose crystallinity index: measurement techniques and their impact on interpreting cellulase performance. Biotechnol Biofuels 3:10CrossRefGoogle Scholar
  27. Petrov OV, Furó I (2009) NMR cryoporometry: principles, applications and potential. Prog Nucl Magn Reson Spectrosc 54:97–122CrossRefGoogle Scholar
  28. Sescousse R, Gavillon R, Budtova T (2011) Aerocellulose from cellulose–ionic liquid solutions: preparation, properties and comparison with cellulose–NaOH and cellulose–NMMO routes. Carbohydr Polym 83:1766–1774CrossRefGoogle Scholar
  29. Široká B, Manian AP, Noisternig MF et al (2012) Wash–dry cycle induced changes in low-ordered parts of regenerated cellulosic fibers. J Appl Polym Sci 126:E397–E408CrossRefGoogle Scholar
  30. Yang Q, Fujisawa S, Saito T, Isogai A (2012) Improvement of mechanical and oxygen barrier properties of cellulose films by controlling drying conditions of regenerated cellulose hydrogels. Cellulose 19:695–703CrossRefGoogle Scholar
  31. Zhang S, Li FX, Yu JY (2010) Structure and properties of novel cellulose fibres produced from NaOH/PEG-treated cotton linters. Iran Polym J 19:949–957Google Scholar
  32. Ziabicki A (1976) Fundamentals of fibre formation: the science of fibre spinning and drawing. Wiley, Minnesota, USAGoogle Scholar
  33. Zuckerstätter G, Schild G, Wollboldt P, Roeder T, Weber HK, Sixta H (2009) The elucidation of cellulose supramolecular structure by 13C CP-MAS NMR. Lenzing Ber 87:38–46Google Scholar
  34. Zuckerstätter G, Terinte N, Sixta H, Schuster KC (2013) Novel insight into cellulose supramolecular structure through 13C CP-MAS NMR spectroscopy and paramagnetic relaxation enhancement. Carbohydrat Polym 93:122–128CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Åsa Östlund
    • 1
    Email author
  • Alexander Idström
    • 1
  • Carina Olsson
    • 2
  • Per Tomas Larsson
    • 3
    • 4
  • Lars Nordstierna
    • 1
  1. 1.Applied Surface ChemistryChalmers University of TechnologyGöteborgSweden
  2. 2.Organic ChemistryChalmers University of TechnologyGöteborgSweden
  3. 3.Innventia ABStockholmSweden
  4. 4.Wallenberg Wood Science CenterKTH Royal Institute of TechnologyStockholmSweden

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