| Abstract
| - Dynamic viscoelastic properties of poly(vinyl chloride) (PVC)/bis(2-ethylhexyl) phthalate(DOP) gels with different molecular weights and various polymer concentrations have been studied as afunction of temperature. These PVC gels exhibited an elastic solid at room temperature and graduallybecame liquid (sol) with increasing temperature. The sol−gel transition took place at a critical geltemperature at which the scaling law of G‘(ω) ∼ G‘‘(ω) ∝ ωn held, allowing an accurate determination ofthe critical gel temperature by means of the frequency independence of the loss tangent. The scalingexponent n obtained was 0.75, independent of temperature as well as molecular weight. This is in goodagreement with the previous results observed at 40 °C and suggests the formation of a similar fractalstructure of the PVC gels. Furthermore, the molecular structure of the gel junctions was analyzed usingthe modified Eldridge−Ferry procedure developed by Tanaka and Nishinari. The junction structure wasfound to be almost independent of molecular weight and gelation temperature, giving a support to thesimilarity of the fractal structure in the PVC gels.
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