After all inhibitor is consumed, viscosity increases nearly vertically (gel point
10,299,995 B2 (Shinobu Hiramatsu, Katsutake Uehiro, Masanori Orita, Kimikazu Fukuda); Kao Corporation, Tokyo, patented a method for producing hydrogel particles that is comprised of the following steps: dissolving a gel agent forming a non-crosslinked hydrogel in an aqueous solution, said aqueous solution of said gel agent having a gel point
of 30[degrees]C or more; putting the aqueous solution into a liquid phase having a temperature of equal to or lower than the gel point
, thereby solidifying the aqueous solution to form a solidified product; and crushing the solidified product.
"As a result, what the gel point
, the minimal complex viscosity and the shear moduli G' & G" from rheological curves, and as well the maximal cure rate and the peak temperature out of differential scanning calorimetry exothermic profiles essentially mean when it comes to an application-oriented formulation are quantitatively interpreted with respect to dynamic modulus, viscosity and the instant extent of cure ...
Here, It is essential to determine the viscosity profiles during the curing process as well as the gel point
for the given system.
During the sol-gel process, there is an enhancement of the viscosity due to the cluster formation, and then, at the gel point
, the emergence of a threedimensional network provokes a divergence of the viscosity and the appearance of elasticity in the material, process that is also known as "amorphous solidification" or "gelation" transition .
was thought to be the time at which the shear storage modulus G' = the shear loss modulus G".
The gel point
was fixed by the loss-flow time of the system, using "the test tube inverting method." The gel point
corresponded to the instant of time after which the system "did not flow" within 40 seconds after the tube had been turned over at a given temperature.
According to field sampling and dewatering until water cut of sample is below 0.5%, then testing gel point
of sample used test method for gel point
of crude oils (Standard, China, SY/T0541-2009) as a reference .
 used the gel point
, GP, to describe the gelation kinetics of Cr(III)/HPAM solutions, experiment results prove that the amount of Cr(III) reacting at the GP is constant for a given polymer and solution pH has been obtained, and the gelation reaction is of first order in Cr(III) rather than second order.
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 .