Gelation Time during Polymerization by Ultrasonic Shear Waves Propagation

Conductivity, proton percolation, and gelation during the network growth in a flexible chain diepoxide and diamine mixture

“…In Table I, t gel at 323.0 and 333.0 K, agrees with the values reported from the viscosity and shear modulus measurements,14 within the combined errors of the two experiments. This shows that decrease of σ 0 during the network polymerization may yield acceptable values of t gel , a conclusion consistent with the previous study 13…”

“…Based on the connectivity of a random network structure, these equations are expressed as, ζ ∼ [( n * − n )/ n *] μ where ζ is the property being measured, n is the number of conducting links in the structure, n * is the number of conducting links at the percolation threshold, and μ is the critical exponent. Recently, gelation time of several polymerizing liquids was determined13 by ultrasonic wave propagation studies, and it was shown that t x may be appropriately identified as t gel . Here we provide a study on a liquid mixture in which molecules form an H‐bond network with maximum protonic conductivity in the liquid before polymerization.…”

Dielectric Polarization and the Stages of a Macromolecule's Growth

“…The t polym,gel values thus determined from eq 17 have been found to agree with the gelation time determined from measurements in real time of the propagation of ultrasonic shear waves through a polymerizing sample, 48 and measurements of the mechanical properties. 8,48 We use eq 17 to analyze the σ 0 values here. Out of the measurements performed at 311 and 343 K and shown in Figure 5B, the σ 0 values for T polym of only 343 K could be determined over a wide enough range for further analysis.…”

Steric hindrance effects on dielectric relaxation and polymerization kinetics of a monoamine-triepoxide mixture, thermochemistry, and diffusion control

“…In a recent study, t gel of several diamine-diepoxide mixtures measured by the ultrasonic (2.25 MHz) shear wave transmission 28 was found to agree with the t gel determined from the DC conductivity data and eq. (1).…”