Production and evaluation of nanopaper from cotton linter by partial dissolution method

Document Type : Complete scientific research article

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Abstract

Background and objectives: The use of cellulose at nanoscale has been greatly studied in the production of biological compounds due to its high strength, low weight and biodegradability. Nanostructures are synthesized through two mechanisms including top-down and bottom-up approaches. In this study, top-down partial dissolution was used as a simple and fast technique to produce nano cellulose. By controlling dissolution parameters such as time, the solvent interrupts the adjacent nanofibrils linking which is supplied through hydrogen bonds, and solves partially outer chains of nanofibril. During solvent rinsing, the partially dissolved chains re-solidified and welded each other, making consolidated structure in which the main components are undissolved native nanofibrils surrounded by cellulose type II and non-crystalline cellulose. Because of this, the final film was named nanopaper. This study considers the characteristics of fully biocompatible nanopaper directly produced from cotton linter fibers by partial dissolution method.
Materials and Methods: Refining the cotton linter fibers were done in three steps; pneumatic, washing with hot water followed by treating with sodium hydroxide. The handsheets were made by TAPPI standard method. The partial dissolution of papers with high content of alpha cellulose were done in the solvent N,N-dimethylacetamide/ 9% lithium chloride (DMAc/LiCL) and translucent cellulose nanopaper was obtained through pressing and drying the resulting gel. To evaluate the properties of the nanopaper, field emission scanning electron microscopy, X-ray diffraction, mechanical properties and thermal gravimetric analysis were used.
Results: The diameter of undissolved nanofibrils in nanopaper fell between 60 and 66 nm. . Electron micrographs showed that nanopaper had more uniformity than paper. Visual transparency (back view) of nanopaper was significant due to the liberalization of cellulose nanostructures, the increase of uniformity and density, the loss of surface roughness and the increase of light transmission. The results of tensile properties showed that the nanopaper tensile stress was higher than that of paper. Paper and nanopaper tensile stress were 8.02 and 27.28 MPa, respectively and tensile modulus elasticity were 0.483 and 0.649 GPa, respectively. X-ray diffraction (XRD) of paper matched cellulose type I. During partial dissolution/re-solidification cellulose type II was appeared and non-crystalline phase increased judging from XRD data. The crystallinity degree of paper and nanopaper were measured 84.9 and 54.89%, respectively. The crystallite size of paper and nanopaper obtained 6.44 and 2.55 nm, respectively. The thermal stability of nanopaper was less than that of paper.
Conclusions: In nanopaper structure, undesolved cellulose type Iβ (undesolved nanofibrils) played reinforcing phase role, and cellulose type (II) and the amorphous cellulose formed the matrix phase. Partial dissolution destroyed part of the crystals and after solvent rinsing and re-solidification, some parts of the amorphous chains were rearranged to form crystals of cellulose type II. Finally, a tough translucent nanopaper was produced by creating consolidated nano structures. The reduction of cellulose crystallinity in nanopaper resulted in the loss of thermal stability in nanopaper.

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1.Azubuike, C.P., Odulaja, J.O., and Okhamafe, A.O. 2012. Physicotechnical, spectroscopic and
thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived
from groundnut shells. Journal of Excipients and Food Chemicals, 3(3): 106-115.
2.Duchemin, B., Newman, R., and Staiger, M.P. 2007. Phase characterisation of all-cellulose
composites. The 16th Internationnal Microscopy Conference on composite materials (ICCM),
Jul 8-13, Kyoto, Japan. 6p.
3.Foner, H.A., and Adan, N. 1983. The characterization of papers by X-Ray diffraction (XRD):
measurement of cellulose crystallinity and determination of mineral composition. Journal of
the Forensic Science Society, 23(4): 313–321.
4.Gindl, W., and Keckes, J. 2005. All-cellulose nanocomposite. Polymer, 46(23): 10221–10225.
5.Gontard, N., Duchez, C., Cuq, B., and Guilbert, S. 1994. Edible composite films of wheat
gluten and lipids: water vapour permeability and other physical properties. Journal of Food
Science and Technology, 29(1): 39-50.
6.Gumuskaya, E., Usta, M., and kirci, H. 2003. The effects of various pulping conditions on
crystalline structure of cellulose in cotton linters. Polymer Degradation and Stability, 81(3):
559-564.
7.Innerlohinger, J., Weber, H.K., and Kraft, G. 2006. Aerocellulose: aerogels and aerogel-like
materials made from cellulose. Macromolecular Symposia, 244(1): 126-135.
8.Klemm, D., Kramer, F., Moritz, S., Lindström, T., Ankerfors, M., Gray, D., and Dorri, A.
2011. Nanocelluloses: A new family of nature-based materials. Angewandte Chemie
International Edition, 50(24): 5438– 5466.
9.Krassig H.A. 1993. Cellulose: structure, accessibility, and reactivity. Gordon and Breach
Science, Switzerland, 240p.
10.Lin, Y.C., Cho, J., Tompsett, G.A., Westmoreland, P.R., and Huber, G.W. 2009. Kinetics
and mechanism of cellulose pyrolysis. The Journal of Physical Chemistry C, 113(46):
20097-20107.
11.Nishino, T., Matsuda, I., and Hirao K. 2004. All-cellulose composite. Macromolecules,
37(20): 7683-7687.
12.Saafan, A.A., and Habib, A.M. 1987. Influence of changes in fine structure on thermal
properties of cotton fiber. Journal of thermal analysis. Calorimetry, 32(5): 1345–1354.
13.Shakeri, A., and P.Staiger, M. 2010. Phase transformations in regenerated microcrystalline
cellulose following dissolution by an ionic liquid. Bioresources, 5(2): 979-989.
14.Siro, I., and Plackett, D. 2010. Microfibrillated cellulose and new nanocomposite materials: a
review. Cellulose, 17(3): 459–494.
15.Troedec, M., Sedan, D., Peyratout, C., Bonnet, J., Smith, A., Guinebretiere, R., Gloaguen,
V., and Krausz, P. 2008. Influence of various chemical treatments on the composition and
structure of hemp fibers. Composite. Part A. 39(3): 514-522.
16.Wang, B., Sain, M., and Oksman, K. 2007. Study of structural morphology of hemp fiber
from the micro to the nanoscale, Applied Composite Materials. 14(2): 89-103.
17.Yousefi, H., Nishino, T., Faezipour, M., Ebrahimi, G., Shakeri, A., and morimune, S. 2010.
All-cellulose nanocomposite made from nanofibrillated cellulose. Advanced Composites
letters. 19(6): 190-195.
18.Yousefi, H., Faezipour, M., Nishino, T., Shakeri, A., and Ebrahimi, G. 2011a. All-cellulose
composite and nanocomposite made from partially dissolved micro- and nanofibers of canola
straw. Polymer Journal, 43(1): 559-564.
19.Yousefi, H., Nishino, T., Faezipour, M., Ebrahimi, G., and Shakeri, A. 2011b. Direct
fabrication of all-cellulose nanocomposite from cellulose microfibers using ionic liquidbased
nanowelding. Biomacromolecules, 12(11): 4080−4085.
20.Zohuriaan-mehr, M.J. 2007. Celloluse and its derivatives. Iran polymer society Press,
Tehran, 60p. (In Persian)