Study of the Effect of Montmorillonite Nanolayers on the Kinetics of Styrene Atom Transfer Radical Polymerization

Document Type : Research Paper

Abstract

Modified nanoclay with a double bond on its modifier structure was employed to study the confinement effect of nanoclay in the atom transfer radical polymerization of styrene. The clay-attached and free polystyrene chains were used as evidence to such a kinetic study. The variations of monomer conversion and the linearity of semi-logarithmic kinetic plot, evidence of the living polymerization and constant radical concentration in the reaction medium, were revealed by the use of gas chromatography technique (GC). Number- and weight- average molecular weights and polydispersity index of polymers were also derived from GPC data. According to the gel permeation chromatography (GPC) results, the number-average molecular weight increases linearly against the monomer conversion indicating the living nature of the polymerization. Free chains which showed higher molecular weights than the attached ones exhibited closer molecular weights values to the theoretical ones. In addition, lower PDI values were obtained in free polystyrene chains. In the case of free polystyrene chains, the initiator efficiency was lower than 1 and by increasing clay content, higher molecular weights were obtained. Attached chains revealed lower molecular weights and their initiator efficiency was higher than 1. By adding clay content, an increase of PDI value and a decrease of molecular weight were observed in attached polystyrene chains. Moreover, all the samples experienced a falling of PDI value from nearly 2 to almost 1.2 as the reaction progressed. FTIR results revealed an interaction between clay surface and monomer causing acceleration in the polymerization kinetic.

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منابع
[1] Jakubowski W. & Matyjaszewski K., “Activator generated by electron transfer for atom transfer radical polymerization”, Macromolecules, Vol. 38, pp. 4139- 4146, 2005.
[2] Patten T. & Matyjaszewski K., “Atom transfer radical polymerization and the synthesis of polymeric materials”, Adv. Mater., Vol. 10, pp. 901-915, 1998.
[3] Wang X.S., Luo N. & Ying S.K., “Controlled/living polymerization of MMA promoted by heterogeneous initiation system (EPN-X-CuX-bpy)”, J. Polym. Sci., Part A: Polym. Chem., Vol. 37, pp. 1255, 1999.
[4] Matyjaszewski K., Nakagawa Y. & Jasieczek C.B., “Polymerization of n-Butyl Acrylate by atom transfer radical polymerization. remarkable effect of ethylene carbonate and other solvents”, Macromolecules, Vol. 31, pp. 1535-1541, 1998.
[5] Haddleton D.M., Heming A.M., Kukulji D., Duncalf D.J. & Shooter A.J., “Atom transfer polymerization of methyl methacrylate. effect of acids and effect with 2-Bromo-2-Methylpropionic acid initiation”, Macromolecules, Vol. 31, pp. 2016-2018, 1998.
[6] Wang X.S. & Armes S.P., “Facile atom transfer radical polymerization of Methoxy-Capped oligo (ethylene glycol) methacrylate in aqueous media at ambient temperature”, Macromolecules, Vol. 33, pp. 6640-6647, 2000.
[7] Chatterjee U., Jewrajka S.K. & Mandal B.M., “The beneficial effect of small amount of water in the ambient temperature atom transfer radical homo and block co-polymerization of methacrylates”, Polymer, Vol. 46, pp. 1575-1582, 2005.
[8] Ray S. & Okamoto M., “Polymer/layered silicate nanocomposites: a review from preparation to processing”, Prog. Polym. Sci., Vol. 28, pp. 1539–1641, 2003.
[9] Tae H. Kim, Lee W. Jang, Dong C. Lee, Hyoung J. Choi, & Myung S. Jhon, “Synthesis and rheology of Intercalated polystyrene/ Na+-montmorillonite nanocomposites”, Maromol. Rapid Commun., Vol. 23, pp. 191-195, 2002.
[10] D.C. Lee & L.W. Jang, “Preparation and characterization of PMMA-Clay hybrid composite by emulsion polymerization”, J. Appl. Polym. Sci., Vol. 61, pp. 1117, 1996.
[11] Zhaohui Tong & Yulin Deng, “Kinetics of miniemulsion polymerization of styrene in the presence of organoclays”, Macromol. Mater. Eng., Vol. 293, pp. 529–537, 2008.
[12] Haimanti D., Nikhil S. & Anil B., “Beneficial effect of nanoclay in atom transfer radical polymerization of ethyl acrylate: a one pot preparation of Tailor-Made polymer nanocomposite”, Macromolecules, Vol. 41, pp. 50-57, 2008.
[13] Behling R.E., Williams B.A., Staade B.L., Wolf L.M. & Cochran E.W., “Influence of graft density on kinetics of Surface-Initiated ATRP of polystyrene from montmorillonite”, Macromolecules, Vol. 42, pp. 1867-1872, 2009.
[14] Abdollahi M. & Semsarzadeh M.A., “Effect of nanoclay and macroinitiator on the kinetics of atom transfer radical Homo- and copolymerization of styrene and methyl methacrylate initiated with CCl3-Terminated poly (Vinyl Acetate) macroinitiator”, European Polymer Journal, Vol. 45, pp. 985-995, 2009.
[15] Yeh J., Liou Sh., Lin Ch., Chang Y., Yu Y., & Cheng Chi., “Effective enhancement of anticorrosive properties of polystyrene by polystyrene-Clay nanocomposite materials”, J. of Appl. Polym. Sci., Vol. 92, pp. 1970–1976, 2004.
[16] Akelah A., Rehab A., Agag T. & Betiha M., “Polystyrene nanocomposite materials by in situ polymerization into Montmorillonite–Vinyl monomer interlayers”, J. Appl. Polym. Sci., Vol. 103, pp. 3739–3750, 2007.
[17] Zhao H., Argoti S., Farrel P. & Shipp A., “Polymer-silicate nanocomposites produced by in situ atom transfer radical polymerization”, J. Polym. Sci. Part A: Polym. Chem., Vol. 42, pp. 916– 924, 2004.
[18] Haimanti D., Nikhil S. & Anil B., “Structure and properties of Tailor-Made poly (ethylacrylate)/Clay nanocomposites prepared by in situ atom transfer radical polymerization”, J. of Appl.Polym. Sci., Vol. 108, pp. 2398–2407, 2008.
[19] Haimanti D., Nikhil S. & Anil B., “Tailor-Made hybrid nanostructure of poly (ethyl acrylate)/ Clay by surface-Initiated atom transfer radical polymerization”, J. of Polym. Sci.: Part A: Polym. Chem., Vol. 46, pp. 5014–5027, 2008.
[20] Tang W. & Matyjaszewski K., “Kinetic modeling of normal ATRP, normal ATRP with [CuII]0, reverse ATRP and SR&NI ATRP”, Macromol Theory Simul, Vol. 17, pp. 359–375, 2008.
[21] Wittmer J.P., Cates M.E., Johner A. & Turner M.S., “Diffusive growth of a polymer layer by in situ polymerization”, Europhys Lett, Vol. 33, pp. 397–402, 1996.
[22] Yoshikawa Ch., Goto A. & Fukuda T., “Reactions of polystyrene radicals in a monomer-free atom transfer radical polymerization system”, e-Polymers, no. 013, 2002.