Heterogeneous networks of polyisoprene/polyvinylethylene

Viscoelastic Behavior of Rubbery Materials

“…The blend is attractive for hetergeneous networks because tertiary vinyl carbons do not sulfurize [65], so that only PI can be vulcanized. This selectivity of sulfur crosslinking in PI/PVE blends is illustrated in DSC curves (Figure 24) [165]. The gel phase is essentially PI, while the soluble fraction is the unreacted PVE.…”

A new paradigm for the molecular basis of rubber elasticity

“…In natural rubber, peroxide crosslinking is thought to produce nodes of functionality 4 (i.e. connecting 4 chains) with a density equal to the stoichiometric concentration, but this is not the case for polybutadiene [20,21]. Since the stress vs. strain data are similar, we conclude that the samples used in both experiments were at about the same crosslink density.…”

“…n is 1-6 in Equation (21). Plots of the change in entropy, as a function of temperature between 250 and 350 K, are shown in Figure 9, parametric on the number of extended states allowed (n ex in the figure).…”

Unconventional Rubber Networks: Circumventing the Compromise Between Stiffness and Strength

“…Consequently, a homogeneous material is not obtained, and thus the mechanical properties are not improved. 101 To avoid this problem, radiation cross-linking at ambient temperature can be used, taking advantage of the greater sensitivity of the PVE to free radical reaction. By this means, the homogeneous morphology is retained, although efforts to date have not yielded the degree of cross-link disparity necessary for optimal properties.…”