Dielectric Properties for the Ring Opening Polymerisation of ε-Caprolactone

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Abstract:

A dielectric property study was performed across a wide range of frequencies and temperatures onring opening polymerisation of ε-caprolactone system in order to relate quantitatively their dielectric properties to microwave heating mechanisms. An analysis of the results concluded that heating mechanism of the polymerisation mixtures in a microwave field was controlled by the dielectric properties of monomer, where the monomer was the major component (>90 % volume/volume) as well as the component with highest dielectric loss and dissipation factor. The penetration depth of mixtures at 2.45 GHz was noted to increase from ~0.58 cm (at 20 C) to ~3.3 cm (at 150 °C). This small penetration depth limits the potential to achieve the successful scale up of a microwave-assisted polymerisation of ε-caprolactone in batch mode at 2.45 GHz. As a result, this will lead to inhomogeneous bulk temperature distribution within the polymerisation mixture and irreproducible chemistry. However, a fast heating rate based on a high value of dissipation factor and dielectric loss of the polymerisation mixtures shows potential to enable the reaction to be completed in a few seconds that may allow the polymerisation to be transferred to a continuous flow process. In so doing, small diameter tubular reactors can be employed hence removing this penetration depth issue. Thus, the polymerisation mixtures dielectric properties are worth to be considered to ensure the reliability and reproducibility of the microwave assisted synthesis of poly-ε-caprolactone at large scale production.

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621-627

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January 2014

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[1] Hutcheon, R., J. Mouris, et al. (2000).

Google Scholar

[2] Scola, D. A., X. M. Fang, et al. (2000). Microwave syntheses of poly(epsilon-caprolactam-co- epsilon-caprolactone)., Journal of Polymer Science Part a-Polymer Chemistry 38(8): 1379-1390.

DOI: 10.1002/(sici)1099-0518(20000415)38:8<1379::aid-pola22>3.0.co;2-f

Google Scholar

[3] Smith, A. D., E. Lester, et al. (2010). Dielectric Properties of Free-Radical Polymerizations: Molecularly Symmetrical Initiators during Thermal Decomposition., Industrial & Engineering Chemistry Research 49(4): 1703-1710.

DOI: 10.1021/ie901201h

Google Scholar

[4] Smith, A. D., E. H. Lester, et al. (2010). Temperature Dependence of the Dielectric Properties of 2, 2'-Azobis(2-methyl-butyronitrile) (AMBN)., Industrial & Engineering Chemistry Research 49(6): 3011-3014.

DOI: 10.1021/ie901389a

Google Scholar

[5] Nakamura, T., R. Nagahata, et al. (2010). In-situ measurement of microwave absorption properties at 2. 45 GHz for the polycondensation of lactic acid., Polymer 51(2): 329-333.

DOI: 10.1016/j.polymer.2009.11.036

Google Scholar

[6] Kamaruddin, M. J., J. El Harfi, et al. (2011). Continuous direct on-line reaction monitoring of a controlled polymerisation via dielectric measurement., Green Chemistry 13(5): 1147-1151.

DOI: 10.1039/c1gc15102a

Google Scholar

[7] Agilent. (2006). Application Note: Basics of Measuring the Dielectric Properties of Materials.

Google Scholar

[8] Pollitt, S., B. Clarke, et al. (2003). A Guide to characterisation of dielectric materials at RF and microwave frequencies. London, The Institute of Measurement and Control.

Google Scholar

[9] Kaatze (2007) Kaatze, U. (2007). Reference liquids for the calibration of dielectric sensors and measurement instruments., Meas. Sci. Technol. 18 967–976.

DOI: 10.1088/0957-0233/18/4/002

Google Scholar

[10] Grantt, J. P., R. N. Clarke, et al. (1989). A critical study of the openended coaxial line sensor technique for RF and microwave complex permittivity measurements, J. Phys. E: Sci. Instrum. 22: 757-770.

DOI: 10.1088/0022-3735/22/9/015

Google Scholar

[11] Jenkins, S., T. E. Hodgetts, et al. (1990). Dielectric measurements on reference liquids using automatic network analysers and calculable geometries., Meas. Sci. Technol. 1: 691-702.

DOI: 10.1088/0957-0233/1/8/005

Google Scholar

[12] Gregory, A. P. and R. N. Clarke (2007). Dielectric metrology with coaxial sensors., Measurement Science & Technology 18(5): 1372-1386.

DOI: 10.1088/0957-0233/18/5/026

Google Scholar

[13] Gregory, A. P., R. N. Clarke, et al. (2008). RF and microwave dielectric measurements upon layered materials using coaxial sensors. Report MAT, NPL. 13.

Google Scholar

[14] Al-Harahsheh, M., S. Kingman, et al. (2009). Dielectric properties of Jordanian oil shales., Fuel Processing Technology 90(10): 1259-1264.

DOI: 10.1016/j.fuproc.2009.06.012

Google Scholar

[15] Pittini, Y. Y., D. Daneshvari, et al. (2008). Cole-Cole plot analysis of dielectric behavior of monoalkyl ethers of polyethylene glycol (CnEm) , European Polymer Journal 44: 1191-1199.

DOI: 10.1016/j.eurpolymj.2008.01.016

Google Scholar

[16] Acros. (2011). MSDS of Epsilon Caprolactone. " Retrieved 13 April 2011, 2011, from http: /www. acros. be/DesktopModules/Acros_Search_Results/Acros_Search_Results. aspx, search_type=CAS&SearchString=502-44-3.

Google Scholar

[17] Debye, P. (1929). Polar Molecules, New York, Chemical Catalog.

Google Scholar

[18] Cole, K. S. and R. H. Cole (1949). Journal Chem. Phys. 9: 341-345.

Google Scholar

[19] Hill, N. E. (1969). Theoritical treatment of permittivity and loss. Dielectric properties and molecular behaviour. T. M. Sugden. London, Van Nostrand Reinhold Company Ltd: 1-107.

Google Scholar

[20] Metaxas, A. C. and R. J. Meredith (1998). Industrial Microwave Heating. London, The Institution of Electrical Engineers.

Google Scholar

[21] Neas, E. D. and M. J. Collins (1988). Microwave Heating Theoretical Concepts and Equipment Design. Introduction To Microwave Sample Preparation. H. M. Kingston and L. B. Jassie. Washington, D. C, American Chemical Society: 7-32.

Google Scholar

[22] Hippel, A. v. (1954). Dielectric Materials and Applications. Cambridge, Massachusetts The M.I.T. Press, The Massachusetts Institute of Technology.

Google Scholar