Poly(vinyl chloride)-based miscible blends: Changes induced in the structural characteristics and in dielectric alpha relaxation of pure poly(vinyl chloride)
A. Elicegui et al., Poly(vinyl chloride)-based miscible blends: Changes induced in the structural characteristics and in dielectric alpha relaxation of pure poly(vinyl chloride), J POL SC PP, 38(1), 2000, pp. 234-247
In this work we investigate by means of dielectric relaxation spectroscopy
how segmental motions occurring in poly(vinyl chloride) (PVC) are modified
by blending of PVC with small amounts of two different homopolymers: crysta
lline poly(epsilon-caprolactone) (PCL) and glassy syndiotactic poly(methylm
ethacrylate) (sPMMA). The dynamics of the ct relaxation of PVC is severely
changed by blending it with PCL or sPMMA becoming faster or slower, respect
ively. Simultaneously, the shape of the relaxation function is being import
antly altered. It shows a stronger non-Debye character being broader and st
rongly temperature-dependent. This fact leads us to calculate distributions
of relaxation times for the blends that are wider in comparison to the one
obtained for pure PVC. Complementary X-ray diffraction measurements have b
een performed in order to assure the absence of crystallinity in the blends
, and some small variations can be deduced at the level of interchain struc
tural correlations of PVC. (C) 2000 John Wiley & Sons.