gel point

Point of incipient network formation in a process forming a chemical or physical polymer network.
Notes:
  1. In both network-forming polymerization and the crosslinking of polymer chains, the gel point is expressed as an extent of chemical reaction (c.f., gel time).
  2. At the gel point a solid (network) material spanning the entire system is formed.
    See also: gel fraction
  3. The gel point is often detected using rheological methods. Different methods can give different gel points because viscosity is tending to infinity at the gel point and a unique value cannot be measured directly.
Source:
PAC, 2007, 79, 1801 (Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials (IUPAC Recommendations 2007)) on page 1809