Dynamic viscoelastic measurements of pvc gels

✍ Scribed by F. Gallego; M.E. Muñoz; J.J. Peña; A. Santamaría

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 423 KB
• Volume: 24
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(88)90195-4

✦ Synopsis

A~tract--This paper deals with dynamic viscoelastic measurements on poly(vinyl chloride)/dioctyl phthalate gels. The curves of the storage modulus, G', vs temperature (at a frequency of 0.1 Hz) show a characteristic gel-like plateau at low temperatures. Using the theory of rubber elasticity, the molecular weights between the associations that constitute the structure of the gel, Me, are obtained for different concentrations and for samples of different molecular weight. It is seen that there is an effect of molecular weight on )k~, which is not the normal behaviour for other polymer gels. The frequency dependence of G' and G" is studied at various temperatures for the range 10 -~ Hz to 102 Hz; the slope of G' vs frequency increases from zero, at gel behaviour temperatures, to values tending to 2, at temperatures above the fusion of the gel and low frequencies. On the other hand the loss tangents show minima at intermediate frequencies, a feature characteristic of entangled polymer systems. We have also carried out complementary measurements on a steady rotation viscometer, the results being in accordance with the values of dynamic complex viscosity.