| Summary: | Yes === In order to improve the frequency-dependent dielectric properties of the immiscible polymeric blends
which were melt-compounded by composing poly (vinylidene fluoride) (PVDF) and low density
polyethylene (LDPE), the layer multiplication and the solid phase orientation technologies were
respectively adopted as two effective strategies to optimize the dispersion state and the orientation of
internal microstructure, aiming at reducing physical porosity and improving the barrier performance
as well as crystal phase of the polymer extrudates. Results comparison showed the dielectric
properties were greatly dependent on the crystal type and the physical porosity density which were
also emphasized as the interfacial effect in the previous work [ref. 29: Lin X et al, J Appl Polym Sci
2015; 132(36), 42507]. It was found that the multilayer-structure manipulation could substantially
improve the dispersion state between the two immiscible components, enhance the mechanical
performance and reduce the internal defects and increase the dielectric constant while keeping the
dielectric loss stable. By uniaxial stretching the sample sheets at a rubber state temperature of ca.
10-20˚C below the melting point, crystal transformation was induced by increasing molecular chains
orientation degree which was also contributed to the enhancement of the dielectric properties. These
techniques implied the potential as a promising way for inducing functional structures of polymeric
blends.
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