Here, It is essential to determine the viscosity profiles during the curing process as well as the gel point
for the given system.
The occurrence of the rheological percolation network reveals, then, a physical gel that can be described by the Winter-Chambon method developed for polymer gel systems [56, 57], In crosslinking polymers, Winter and Chambon proposed that at the gel point
the loss and storage modulus were congruent and proportional to of over the whole range 0 < [omega] < [infinity] of frequency, where n is the relaxation exponent (0 < n < 1).
Tung and Dynes, suggested that, the time at which the crossover of G' and G" occurs during isothermal curing can be taken as gel point
(Tung and Dynes, 1982).
If you use a sugar thermometer the gel point
is 104c if not, start testing when the bubbles start breaking more slowly.
At the gel point
an infinitely large cluster extends throughout the whole system, and a three-dimensional continuous network is formed .
Figure 2 shows the relationship between theoretical gel point
He has been a pioneer in the development and commercialization of a process to produce EPDM containing high levels of vinyl norbomene without reaching the gel point
But B20 (20% biodiesel, 80% regular diesel--more commonly available than B100) has a gel point
The method reported by Barminas and Osemeahon (2006) was adopted for the determination of viscosity and gel point
of the UF resins.
But once o-o-p methylol attains the threshold limit, the network formation is rapid, arising out of the availability of a higher concentration of o-o and o-p methylols and their resoles, which help o-o-p methylol to form a network very quickly and reach the gel point
It extends the gel point
and allows extended foam flow, especially when used with a strong blowing catalyst.
Many researchers have shown that the crossover of G' and G" is a good indication of gel point