Thermally stimulated depolarization current investigations of copolyesteramide (Vectra B 950) polymer liquid crystal

• Autorzy: Quamara, J. K. , Mahna, S. K. , Garg, S.
• Języki publikacji: EN

Abstrakty

EN

Thermally stimulated depolarization current (TSDC) characteristics of copolyesteramide (Vectra B950), a polymer liquid crystal having a monomeric composition of 60/20/20 mol % of 6-hydroxy-2 -naphthoic acid (HNA), terethalic acid (TA) and 4-aminophenol (AP) were investigated in the tempera-ture range 20-250 °C in function of polarizing temperature (80-190 °C), polarizing field (2.77-13.88 kV/cm), polarization time (0.5-2 h) and storage time (1 - 100 h). The TSDC spectra in general comprise four maxima, namely ß', ß, ?, and ? with their respective locations around 30°C, 110 °C, 160 °C and 220 °C. The ß peak was attributed to the dipolar nature of the carbonyl group (> C = O) present in HNA and TA non liquid crystalline phase of Vectra B, whereas the ß' peak is due to the dipolar nature of the ester group. The ? peak was assigned to a space charge trapping mechanism. A major contribution towards ? relaxation comes from interfacial polarization arising from liquid crystalline phase inVectra B. A high temperature of the ? relaxation is associated with the onset of melting due to the movement of large segmental groups of liquid crystalline phase.

Słowa kluczowe

EN

Vectra B; polymer liquid crystal; thermally stimulated depolarization current

• Czasopismo: Materials Science Poland
• Rocznik: 2010
• Tom: Vol. 28, No. 3
• Strony: 679--691
• Opis fizyczny: Bibliogr. 38 poz.

Twórcy

autor

Quamara, J. K.

autor

Mahna, S. K.

autor

Garg, S.

• Department of Physics, National Institute of Technology, Kurukshetra 136119, India

Bibliografia

• [1] ROVIELLO A., SIRIGU A., J. Polym. Sci. Polym. Lett., 13 (1975), 455.
• [2] JACKSON W.J. Jr., KHUFFUSS H.F., Polymer Sci. Polymer Chem., 14 (1976), 2043.
• [3] FLORY P.J., ABE A., Macromolecules, 11 (1978), 1122.
• [4] BROSTOW W., Kunststoffe, 78 (1988), 411.
• [5] GEDDE U.W., LIU F., HULT A., SAHLEN F., BOYD R.H., Polymer, 33 (1994), 2056.
• [6] QUAMARA J.K., KAUSHIK B.K., Indian J. Pure Appl. Phys., 34 (1996), 553.
• [7] WEISS R.A., SHAO L., LUNDBERG R.D., Macromolecules, 25 (1992), 6370.
• [8] GOULD S.A.C., SHULMAN J.B., SCHIRALDI D.A., OCCELLI M.L., J. Appl. Polym. Sci., 74 (1999), 2243
• [9] MANDAL P.K., BANDYOPADHYAY D., CHAKRABARTY D., J. Appl. Polym. Sci., 88 (2003), 767.
• [10] VALLEJO F.J., EGUIAZABAL J.I., NAZABAL J., Polym. Engg. Sci., 39 (1999), 1726.
• [11] DREHER S., SEIFERT S., ZACHMANN H.G., MOSZNER N., MERCOLI P., ZANGHELLINI G., J. Appl. Polym Sci., 67 (1998), 531.
• [12] VAN TURNHOUT J., [In:] Electrets, G.M. Sessler (Ed.), Springer, Berlin, (1980), 81.
• [13] BOERSMA A., VAN TURNHOUT J., WUBBENHORST M., Macromolecules, 31 (1998), 7453.
• [14] US Patent 5834560, Liquid Crystal Polymers, November 10, (1998).
• [15] CHUNG SHUNG T., [In:] Thermotropic Liquid Crystal Polymer, CRC Press, (2001), 41.
• [16] QUAMARA J.K., PILLAI P.K.C., SHARMA B.L., Acta Polym., 33 (1982), 205.
• [17] SESSLER G.M., [In:] Electrets, Springer, Berlin, 33 (1980), 13.
• [18] GROSS B., J. Chem. Phys., 17 (1949), 866.
• [19] REDDISH W., Trans. Faraday Soc., 46 (1950), 459.
• [20] BHARDWAJ R.P., QUAMARA J.K., NAGPAL K.K., SHARMA B.L., Phys Status sol. (a)., 77 (1983), 347.
• [21] GARG M., KUMAR S., QUAMARA J.K., Indian J. Pure Appl. Phys., 39 (2001), 259.
• [22] HINO T., SUZUKI K., YAMASHITA K., Japan J. Appl. Phys., 12 (1973), 651.
• [23] TURNHOUT VAN J., [In:] Thermally Stimulated Discharge of Polymer Electrets, Elsevier, Amsterdam (1975).
• [24] SOLUNOV H., VASSILEV T., J. Polym. Sci. Polym. Phys., 12 (1974), 1273.
• [25] LENZ R.W., Faraday Disc., 79 (1985), 21.
• [26] BROSTOW W., KAUSHIK B.K., MAL S.B., TALWAR I.M., Polymer, 33 (1992), 22.
• [27] SHEPARD D.D., TWOMBLY B., Thermiochim. Acta, 272 (1996), 125.
• [28] MATSUOKA S., [In:] Relaxation Phenomenon in Polymer, Hansar Publ., New York (1992), 211.
• [29] CHUNG SHUNG T., [In:] Thermotropic Liquid Crystal Polymer, CRC Press, (2001), 88.
• [30] HUO P., CEBE P., Polymer Sci., Part B: Polymer Phys., 30 (1992), 239.
• [31] JOSHI S., RADHAKRISHAN S., Thin Solid Films, 142 (1986), 213.
• [32] QUAMARA J. K., SRIDHARBABU Y., Indian J. Pure Appl. Phys., 41 (2003), 790.
• [33] BROSTOW W., SAMATOWICZ D., Polym. Eng. Sci., 1 (1992), 87.
• [34] QUAMARA J.K., MANHA S.K., GARG S., Int. J. Polym. Anal. Charact., 15 (2010), 298.
• [35] COLE K.S., COLE R.H., J. Chem. Phys., 19 (1951), 1484.
• [36] WAGNER K.W., Ann. Phys., 40 (1913), 817.
• [37] FROHLICH H., [In:] Theory of Dielectrics, Oxford University Press, London, 1958.
• [38] GARG M., QUAMARA J.K., Nucl. Instr. Meth. B, 246 (2006), 355.