Back
 OJIC  Vol.3 No.2 , April 2013
Thermally induced gelation of alumina shaping-neutron scattering and rheological measurements
Abstract: Thermally induced gelation forming based on methylcellulose is recently being explored as a simple and environmentally benign process. Alumina slurry containing 0.1 wt% methylcellulose is subjected to Quasi Elastic Neutron Scattering (QENS) and rheological measurements in gelation temperature regimes to evolve a possible mechanism of the forming process. A reduction in diffusivity of water in the slurry from 2.16 to 1.92 × 10-5 cm 2 ·s-1after exposure to 55°C is observed with QENS. This is found to be well correlated with a steep increase in viscosity from 1.2 Pa.s till 50°C to 50,000 Pa.s at 55°C. QENS studies revealed the diffusion of water occurs by jump diffusion with the jump lengths distributed randomly. Further, for the entire sample much longer residence time is found as compared to bulk water, which is due to hydrophilic interaction of water molecules with the methylcellulose in the slurry. Reduction in diffusivity of water along with the steep increase in viscosity could be understood as the strong, cross-linked polymer-solvent irreversible gel formation in presence of alumina which is responsible for the retention of a consolidated shape of the ceramic green body. Samples maintained the integrity while heat treatments achieving close to theoretical density values of3.98 g·cm-3 at 1550°C.
Cite this paper: Biswas, P. , Rajeswari, K. , Chaitanya, S. , Johnson, R. , Prabhudesai, S. , Sharma, V. , Mitra, S. and Mukhopadhyay, R. (2013) Thermally induced gelation of alumina shaping-neutron scattering and rheological measurements. Open Journal of Inorganic Chemistry, 3, 48-54. doi: 10.4236/ojic.2013.32007.
References

[1]   Scheutz, J.E. (1986) Methyl cellulose polymers as binders for extrusion of ceramics. Journal of the American Ceramic Society, 88, 1556-1559.

[2]   Lange, F.F. (1989) Powder processing science and technology for increased reliability. Journal of the American Ceramic Society, 72, 3-10. doi:10.1111/j.1151-2916.1989.tb05945.x

[3]   Rivers, R.D. (1978) Method of injection moulding powder metal parts. US Patent 4113480.

[4]   Bayer, R. and Knarr, M. (2012) Thermal precipitation or gelling behaviour of dissolved methyl cellulose (MC) derivatives—Behaviour in water and influence on the extrusion of ceramic paste. Part 1: Fundamental of MC derivatives. Journal of European Ceramic Society, 32, Article ID: 10071018. doi:10.1016/j.jeurceramsoc.2011.11.025

[5]   Koda, S., Hori, T., Nomura, H. and Kawaizumi, F. (1991) Hydration of methyl cellulose. Polymer, 32, 2806-2810. doi:10.1016/0032-3861(91)90112-V

[6]   Xu, X., Wen, Z., Lin, J., Li, N. and Wu, X. (2010) An aqueous gel-casting process for ?-LiAlO2 ceramics. Ceramic International, 36, 187-191. doi:10.1016/j.ceramint.2009.07.017

[7]   Biswas, P., Swathi, M., Ramavath, P., Rajeswari, K., Suresh, M.B. and Johnson, R. (2012) Diametral deformation behaviour and machinability of methyl cellulose thermal gel cast processed alumina ceramics. Ceramic International, 38, 6115-6121. doi:10.1016/j.ceramint.2012.04.059

[8]   Hareesh, U.S., Anantharaju, R., Biswas, P., Rajeswari, K. and Johnson, R. (2011) Colloidal shaping of alumina ceramics by thermally induced gelation of methyl cellulose. Journal of the American Ceramic Society, 94, 749-753. doi:10.1111/j.1551-2916.2010.04188.x

[9]   Sarkar, N. and Greminger Jr., G.K. (1983) Methyl cellulose polymers as multifunctional processing aids in ceramics. American Ceramic Bulletin, 62, 1280-1284.

[10]   K?rger, J. and Ruthven, D.M. (1992) Diffusion in zeolites and other microporous solids. Wiley Interscience, New York.

[11]   Bée, M. (1988) Quasielastic neutron scattering. Adam Hilger, Bristol.

[12]   Sharma, V.K., Mitra, S., Kumar, A., Yusuf, S.M., Juranyi, F. and Mukhopadhyay, R. (2011) Diffusion of water in molecular magnet Cu0.75Mn0.75[Fe(CN)6]?7H2O. Journal Physics: Condensed Matter, 23, 446002-446009. doi:10.1088/0953-8984/23/44/446002

[13]   Sharma, V.K., Mitra, S., Singh, P., Jurany, F. and Mukhopadhyay, R. (2010) Diffusion of water in nano-porous polyamide membranes: Quasielastic neutron scattering study. The European Physical Journal Special Topics, 189, 217-221. doi:10.1140/epjst/e2010-01325-9

[14]   Sharma, V.K., Singh, P.S., Gautam, S., Mitra, S. and Mukhopadhyay, R. (2009) Diffusion of water in nanoporous NF polyamide membrane. Chemical Physics Letter, 478, 56-60. doi:10.1016/j.cplett.2009.07.045

[15]   Sharma, V.K., Singh, P.S., Gautam, S., Maheshwari, P., Dutta, D. and Mukhopadhyay, R. (2009) Dynamics of water sorbed in reverse osmosis polyamide membrane. Journal of Membrane Science, 326, 667-671. doi:10.1016/j.memsci.2008.11.003

[16]   Mitra, S., Mukhopadhyay, R., Tsukushi, I. and Ikeda, S. (2001) Dynamics of water in con?ned space (porous alumina): QENS study. Journal Physics: Condensed Matter, 13, 8455-8465. doi:10.1088/0953-8984/13/37/302

[17]   Chakrabarty, D., Gautam, S., Mitra, S., Gil, A., Vicente, M.A. and Mukhopadhyay, R. (2006) Dynamics of absorbed water in saponite clay: Neutron scattering study. Chemical Physics Letter, 426, 296-300. doi:10.1016/j.cplett.2006.05.131

[18]   Mitra, S., Pramanik, A., Chakrabarty, D., Jurányi, F., Gautam, S. and Mukhopadhyay, R. (2007) Diffusion of water adsorbed in hydrotalcite: Neutron scattering Study. Journal of Physics: Conference Series, 92, 012167-012171. doi:10.1088/1742-6596/92/1/012167

[19]   Sharma, V.K., Gautam, S., Mitra, S., Rao, M.N., Tripathi, A.K., Chaplot, S.L. and Mukhopadhyay, R. (2009) Dynamics of adsorbed hydrocarbon in nanoporous zeolite framework. Journal of Physical Chemistry B, 113, 8066-8072. doi:10.1021/jp9014405

[20]   Sharma, V.K., Mitra, S., Sakai, V.G., Hassan, P.A., Embs, J.P. and Mukhopadhyay, R. (2012) The dynamical landscape in CTAB micelles. Soft Matter, 8, 7151-1760. doi:10.1039/c2sm25515d

[21]   Mukhopadhyay, R., Mitra, S., Paranjpe, S.K. and Dasannacharya, B.A. (2001) Quasielastic neutron scattering facility at Dhruva reactor. Nuclear Instrumentation Method A, 474, 55-66.

[22]   Chudley, C.T. and Elliott, R.J. (1961) Neutron scattering from a liquid on a jump diffusion model. Proceedings Physics Society, 77, 353-361. doi:10.1088/0370-1328/77/2/319

[23]   Egelstaff, P.A. (1967) An introduction to the liquid state. Academic Press, London.

[24]   Hall, P.L. and Ross, D.K. (1981) Incoherent neutron scattering functions for random jump diffusion in bounded and infinite media. Molecular Physics, 42, 673-682. doi:10.1080/00268978100100521

[25]   Singwi, K.S. and Sjolander, A. (1960) Diffusive motions in water and cold neutron scattering. Physical Review, 119, 863-871. doi:10.1103/PhysRev.119.863?

[26]   Tiexiera, J., Bellissent-Funel, M.C., Chen, S.H. and Dianoux, A.J. (1985) Experimental determination of the nature of diffusive motions of water molecules at low temperatures. Physical Review A, 31, 1913-1917. doi:10.1103/PhysRevA.31.1913

 
 
Top