Dielectric Relaxation Process and Microwave Heating Mechanism in ε-Caprolactone as a Function of Frequency and Temperature

Abstract:

Dielectric properties of materials play a significant role in design of microwave assisted processing system. This paper is focused on the dielectric properties of ε-caprolactone (ε-cap) which is the monomer for the biodegradable polymer, Poly (ε-caprolactone) (PCL). The dielectric properties of ε-cap were measured across a wide range of frequencies (0.1 GHz5.0 GHz) and temperatures (20-150oC). Then the measured dielectric properties data was modelled using Debye model in order to relate quantitatively the dielectric properties to microwave heating mechanisms. The analysis carried out gives a clear picture of interaction of ε-cap with microwave energy and its heating mechanism in microwave assisted polymerisation process. This study concluded that microwave heating mechanism of the ε-cap in the measured range may be dominated by the dipole reorientation.

• Periodical: Advanced Materials Research (Volumes 931-932)
• Pages: 205-209
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.931-932.205
• Online since: May 2014
• Authors: Mohd Johari Kamaruddin*, Anwar Johari, Ramli Mat, Tuan Amran Tuan Abdullah, Siti Hamidah Mohd Setapar, Wan Rosli Wan Sulaiman, Asmadi Ali
• Keywords: Debye Relaxation Model, Dielectric Property, Microwave Assisted Polymerisation, Microwave Heating Mechanism, Relaxation Frequency, Relaxation Time

References

[1] M. J. Kamaruddin, A.Z. Muhammad Abbas, et al., Dielectric Properties for the Ring Opening Polymerisation of ε-Caprolactone submitted to Applied Mechanics and Materials Journal, Trans Tech Publications (2013).

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

DOI: 10.1039/c1gc15102a

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

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

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

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

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

[7] E.D. Neas, M.J. Collins, Microwave heating theoretical concepts and equipment design, in: H.M. Kingston, L.B. Jassie, Introduction to Microwave Sample Preparation, American Chemical Society, Washington, D. C, 1988, pp.7-32.

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

[9] N. E. Hill, Theoretical treatment of permittivity and loss, in: T. M. Sugden, Dielectric properties and molecular behaviour, Van Nostrand Reinhold Company Ltd., London, 1969, pp.1-107.

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

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

[11] G. Williams, and D. C. Watts, Multiple dielectric relaxation processes in amorphous polymers as a function of frequency, temperature and applied pressure, The 161st National meeting of the American Chemical Society, Plenum Press, Los Angeles, California, (1971).

DOI: 10.1007/978-1-4615-8669-2_2

[12] D. F. Stein, R. H. Edgar, et al., Microwave processing of materials, National Academic of Sciences, Washington, D.C., 1994, pp.5-59.