Effect of crystalline phase, orientation and temperature on the dielectric properties of poly (vinylidene fluoride) (PVDF)

摘要

The effect of crystalline phase , uniaxial drawingand temperature on the real (ε') imaginary (ε")parts of therelative complex permittivity of poly(vinylidene fluoride) (PVDF)was studied in the frequency range between 102 and 106 Hz.Samples containing predominantly αand βphases, or a mixtureof these , were obtained by crystallization from a DMF solution atdifferent temperatures. αphase samples were also obtained frommelt crystallization and from commercial drawing of αandβphase samples. The results showed that the crystalline phase exertsstrong influence on the values of ε' andε", indicating that theαa relaxation process, associated with the glass transition ofPVDF, is not exclusively related to the amorphous region of thepolymer. An interphase region, which maintains theconformational characteristics of the crystalline regions, shouldinfluence the process decisively.