Dynamic‐mechanical behavior of poly(vinyl chloride), PVC, and chlorinated PVC compounds in the range of processing temperatures

Abstract

Both real and imaginary components of the complex shear viscosity have been determined as a function of strain amplitude, frequency and temperature for various samples of poly(viny1 chloride), PVC, and chlorinated PVC of increasing chlorine content, with the aid of a Rheometrics mechanical spectrometer using eccentric rotating disk geometry. Different methods of sample preparation (low temperature dryblending, high temperature extrusion or calendering) were used to study thermomechanical history effects. Results obtained in the region of "linear" viscoelastic behavior were compared with those of capillary flow experiments: at relatively high temperatures the validity of the Cox-Merz relationship was confirmed. Use of time-temperature superposition procedures made it possible to predict the important variation of viscosity over a broad range of shear rates. The experimental results in particular with regard to the strong influence of temperature and thermal history, were tentatively interpreted in terms of a supermolecular structure due to the presence of ordered domains (microcrystallites) of variable amount and size. This interpretation was shown to be consistent with differential scanning calorimetry.

Rheological and mechanical properties of poly(vinyl chloride)/chlorinated poly(vinyl chloride) miscible blends

“…7 ) . Consistent with our results are those of Bonnebat and DeVries, who found that a CPVC containing 65.8 percent chlorine (presumably chlorinated in a fluidized bed) also showed a lower viscosity than PVC in the 140 to 150°C range, but only at a low frequency (0.1 Hz/2a) (28).…”

The effect of crystallites on the rheological properties of microphase‐separated PVC‐PBA‐PVC triblock copolymers obtained by single electron transfer‐degenerative chain transfer living radical polymerization

“…In fact, the alteration of the terminal zone provoked by either the microphase separation or the microcrystalline structure of PVC was very similar. The crystallites acted as physical crosslinking points, giving rise to slightly frequency dependent dynamic moduli and G 0 > G 00 , even at temperatures close to 200 C [32,33]. This finding is not surprising, considering that PVC particles have crystallites of varying sizes with a broad melting range, practically from 100 C to 230 C [13,14].…”