Title

The effect of fibre concentration on the α to β-phase transformation, degree of crystallinity and electrical properties of vapour grown carbon nanofibre/poly(vinylidene fluoride) composites

RIS ID

99315

Publication Details

Costa, P., Silva, J., Sencadas, V., Costa, C. M., Van Hattum, F. W.J., Rocha, J. G. & Lanceros-Méndez, S. (2009). The effect of fibre concentration on the α to β-phase transformation, degree of crystallinity and electrical properties of vapour grown carbon nanofibre/poly(vinylidene fluoride) composites. Carbon, 47 (11), 2590-2599.

Abstract

Vapour growth carbon nanofibres/poly(vinilidene fluoride) - VGCNF/PVDF - composites prepared by solution casting were studied. The spherulitic crystallisation morphology of the pure polymer is maintained for the composites. Mechanical stretching of the composite films induces the α to β-phase transformation within the polymer matrix. This phase transition is accompanied by the destruction of the spherulitic microstructure in favour of a microfibrillar one. The incorporation of the VGCNF in the PVDF matrix increases the degree of crystallinity of the polymer composites for concentrations lower than ∼1%, remaining stable for higher VGCNF concentrations. With respect to the electrical properties, the stretching associated to the phase transformation induces a change in the conduction mechanism: the α-phase composite demonstrates a percolative behaviour on the measured conductivity whereas the β-phase demonstrates typical ionic conduction behaviour. Dielectric measurements in conjunction with the the two exponent percolation phenomenological equation demonstrates that in the β-phase an effective reduction in the ratio VGCNF length/domain length could induce the observed percolation behaviour.

Please refer to publisher version or contact your library.

Share

COinS
 

Link to publisher version (DOI)

http://dx.doi.org/10.1016/j.carbon.2009.05.011