Specific heat and thermal diffusivity of vinylidene fluoride/trifluoroethylene copolymers

Authors

  • Y. W. Wong,

    Corresponding author
    1. Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
    • Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
    Search for more papers by this author
  • N. M. Hui,

    1. Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
    Search for more papers by this author
  • E. L. Ong,

    1. Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
    Search for more papers by this author
  • H. L. W. Chan,

    1. Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
    Search for more papers by this author
  • C. L. Choy

    1. Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
    Search for more papers by this author

Abstract

The specific heat (C) and thermal diffusivity (D) of vinylidene fluoride (VDF)/trifluoroethylene copolymers with 70 and 56 mol % of VDF were measured between 200 and 390 K, and the thermal conductivity (K) was calculated from these data. C, D, and K were rather insensitive to the VDF content but varied significantly with the crystallinity. At room temperature, as the crystallinity increased from about 55 to 85%, C decreased by 17%, and D and K increased by 60 and 40%, respectively. For the copolymer with 70 mol % VDF, C exhibited a broad peak, whereas D showed an abrupt drop at the ferroelectric–paraelectric transition near 370 K on heating. The transition temperature on cooling was about 40 K below that observed in the heating run, thus revealing a large thermal hysteresis. For the copolymer with 56 mol % VDF, the transition temperature was much lower, the transition region was narrower, and the thermal hysteresis was barely observable. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3160–3166, 2003

Ancillary