Dielectric Behavior of PVC Gels and Sols in Dioctyl Phthalate.

Viscoelastic Properties of Poly(vinyl chloride) Sols

“…The significant decrease of J pol with T is attributable to decreases of the network size and degree of branching due to partial dissolution of the crystal domains. This partial dissolution was noted also in a recent dielectric study of the PVC sol …”

“…This partial dissolution was noted also in a recent dielectric study of the PVC sol. 34 The above features of the PVC sols in DOP are similar to the features of the sols in other solvents. 30,31 Guenet and co-workers 30 reported that the sols in diethyl malonate included two types (weak-and strong-type) of physical cross-links, and the weak-type cross-links are easily dissolved with increasing T. The partial dissolution of the crystal domains (physical cross-links) in our PVC/DOP sols may be related to similar, weak domains.…”

“…For these gels in a vicinity of the gelation point, the equilibrium modulus G e at constant T (40 °C) exhibited power-law behavior, G e ∝ ε z with ε = | c − c g |/ c g being a normalized distance from the gelation point suggesting a similarity of the gel network structure for various M 1 Characteristics of PVC Samples a code10 -3 M w b M w / M n c PVC4 39.4 1.89 PVC9 87.4 2.01 PVC17 173 2.24 a The samples have the triad tacticity of syndio:hetero:iso = 0.33:0.49:0.18 (determined from NMR) …”

Viscoelastic Properties of Poly(vinyl chloride) Gels: Universality of Gel Elasticity

“…In attempt to rheologically characterize the PVC gels, we − recently began a series of studies for PVC gels. For the critical PVC gel at the sol−gel transition concentration (gelation point) c g , the storage and loss moduli, G ‘ and G ‘ ‘, exhibited the characteristic power-law dependence on the angular frequency ω , ,, The exponent, n = 0.75, was independent of the PVC molecular weight M , the molecular weight distribution, temperature T , and the plasticizer solubility toward PVC, suggesting that the PVC critical gels included a similar fractal network structure irrespective of these factors. c g decreased in proportion to M w -1 and with decreasing plasticizer solubility 19 (and/or, equivalently, with decreasing T 18 ).…”

“…For the critical PVC gel at the sol-gel transition concentration (gelation point) c g , the storage and loss moduli, G′ and G′′, exhibited the characteristic powerlaw dependence 21 on the angular frequency ω, 13,17,18 The exponent, n ) 0.75, was independent of the PVC molecular weight M, 13 the molecular weight distribution, 17 temperature T, 18 and the plasticizer solubility toward PVC, 19 suggesting that the PVC critical gels included a similar fractal network structure irrespective of these factors. c g decreased in proportion to M w -1 and with decreasing plasticizer solubility 19 (and/or, equivalently, with decreasing T 18 ). These results demonstrated an important role of the chain size and crystallizability in the critical gel formation.…”