AC Electrical and Structural Properties of Polymethylmethacrylate/Aluminum Composites

Abstract

Different concentrations (i.e., 10, 20, 30, and 40 wt%) of Al metal are dispersed in polymethylmethacrylate (PMMA) matrix and the composite films are prepared by solution casting method. The frequency and temperature dependence of dielectric constant, dielectric loss, and conductivity of pure polymer and polymer composites filled with Al-metal filler are studied in the broad frequency range from 100 Hz to 10 MHz and in the temperature range 25—80°C. It is observed that the dielectric constant, dielectric loss, and electrical conductivity gradually increase with filler concentration and also with temperature and is explained in terms of hopping conduction mechanism. The electrical conductivity of the composites obeys universal power law model (i.e., σ = Af ⁿ), where n is power exponent. A comparison of dielectric constant values of PMMA/Al composites is made with predictions of theoretical models and it is observed that an empirical power equation gives a better fit to our results. Structural property of the composites is studied by means of X-ray diffraction. The results show that the crystallinity and crystalline size increase with increasing concentration of aluminum filler. Average surface roughness is observed to change with filler concentration as obtained from atomic force microscopy and scanning electron microscopy analysis.

Keywords

polymer composites AC electrical properties XRD AFM.

Get full access to this article

View all access options for this article.

References

Huang, X.Y. , Jiang, P.K. and Kim, C.U. ( 2007). Electrical Properties of Polyethylene/ Aluminum Nanocomposites , J. Appl. Phys., 102: 124103.

Shen, Y. , Yue, Z.X. , Li, M. and Nan, C.W. ( 2000). Enhanced Initial Permeability and Dielectric Constant in a Double- Percolating Ni0.3Zn0.7Fe1.95O4-Ni- Polymer Composite, Adv. Funct. Mater., 15(7): 1100-1103.

Stuffer, D. ( 1985). Introduction to Percolation Theory, Taylor and Francis, London.

Dang, Z.-M. , Zhang, Y.-H. and Tjong, S.-C. ( 2004). Dependence of Dielectric Behavior on the Physical Property of Fillers in the Polymer-matrix Composites, Syn. Met., 146: 79-84.

Brosseau, C. , Queffelec, P. and Talbot, P. (2001). Microwave Characterization of Filled Polymers, J. Appl. Phys., 89: 4532-4540.

Panda, M. , Srinivas, V. and Thakur, A.K. ( 2008). On the Question of Percolation Threshold in Polyvinylidene Fluoride/Nanocrystalline Nickel Composites, Appl. Phys. Lett. , 92: 132905-132907.

Mamunya, Y.P. , Muzychenko, Y.V. , Pissis, P. , Lebedev, E.V. and Shut, M.I. (2000). Percolation Phenomena in Polymers Containing Dispersed Iron, Polym. Eng. Sci., 42: 90-100.

Dang, Z.M. , Fan, L.Z. , Shen, Y. and Nan, C.W. ( 2003). Study on Dielectric Behavior of a Three-phase CF/(PVDF + BaTiO3) Composite, Chem. Phys. Lett., 369: 95-100.

Dang, Z.-M. , Lin, Y.-H. and Nan, C.-W. ( 2003). Novel Ferroelectric Polymer Composites with High Dielectric Constants, Adv. Matter., 15(19): 1625-1629.

10.

Ahmad, K. , Pan, W. and Shi, S.-L. ( 2006). Electrical Conductivity and Dielectric Properties of Multiwalled Carbon Nanotube and Alumina Composites, Appl. Phys. Lett., 89: 133122-133124.

11.

Van Beek, L.K.H. (1967). Progress in Dielectric , Heywood, London.

12.

Qureshi, A. , Mergen, A. , Mehmet, S.E. , Gulluoglu, A. and Singh, N.L. (2008). Dielectric Properties of Polymer Composites Filled with Different Metals, J. Macromol. Sci. A., 45: 462-469.

13.

Berger, M.A. and McCullough, R.L. (1985). Characterization and Analysis of the Electrical Properties of a Metal-Filled Polymer, Compos. Sci. Technol., 22(2): 81-106.

14.

Singh, V. , Kulkarni, A.R. and Rama Mohan, T.R. ( 2003). Dielectric Properties of Aluminum-Epoxy Composites, J. Appl. Polm. Sci., 90: 3602-3608.

15.

Elimat, Z.M. , Zihlif, A.M. and Ragosta, G. ( 2008). Study of AC Electrical Properties of Aluminum Epoxy Composites , J. Phys D. Appl. Phys., 41: 165408 (page 7).

16.

Baziard, Y. , Breton, S. , Tourain, S. and Gourdenne, A. ( 1988). Dielectric Properties of Copper Powder-Epoxy Resin Composites, Eur. Polm. J., 24(77): 633-638.

17.

Doyle, W.T. and Jacobs, I.S. ( 1990). Effective Cluster Model of Dielectric Enhancement in Metal-Insulator Composites, J. Phys. Rev. B Condens. Matter. , 42: 9319.

18.

Singh, N.L. , Shah, S. , Qureshi, A. , Singh, F. , Avasthi, D.K. and Ganesan, V. ( 2008). Swift Heavy Ion Induced Modification in Dielectric and Microhardness Properties of Polymer Composites, Polym. Degrad. Stab., 93: 1088-1093.

19.

Singh, N.L. , Sharma, A. , Shrinet, V. , Rakshit, A.K. and Avasthi, D.K. ( 2004). Electrical Properties of Ion Irradiated Polypropylene Films, Bull. Mater. Sci., 27: 263-267.

20.

de Oliveira, H.P. , dos Santos, M.V.B. , dos Santos , C.G. and de Melo, C.P. (2003). Preparation and Electrical and Dielectric Characterization of PVA/PPY Blends , Mater. Charact., 50: 223-226.

21.

Elmat, Z.M. ( 2006). Ac Electrical Conductivity of Poly(Methylmethacrylate)/Carbon Black Composites, J. Phys. D. Appl. Phys., 39: 2824-2828.

22.

Singh, D. , Singh, N.L. , Qureshi, A. , Kulriya, P. , Tripathi, A. , Avasthi, D.K. and Gulluoglu Arif, N. ( 2010). Radiation Induced Modification of Dielectric and Structural Properties of Cu/ PMMA Polymer Composites, J. Non-Crystal Solids, 356: 856-863.

23.

Papathanassiou, A.N. , Sakellis, I. and Grammatikakis , J. (2007). Universal Frequency-dependent AC Conductivity of Conducting Polymer Networks , Appl. Phys. Lett., 97: 122911.

24.

Cullity, B.D. (1978). Elements of X-ray Diffraction , 2nd edn, Addison-Wesley, New York.

25.

Yan, X. , Tao, X. , Shan, X. , Xiaobo, W. and Shengrong, Y. (2004). Nanotechnology Fabrication of Polymer-converted Carbon Films Containing Ag, Pd Nanoparticles, Nanotechnology, 15: 1759-1762.