polymer chemistry
Polymer chemistry is a sub-discipline of chemistry that focuses on the structures of chemicals, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are a ...
, the gel point is an abrupt change in the
viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
of a solution containing polymerizable components. At the gel point, a solution undergoes gelation as reflected in a loss in fluidity. Gelation is characteristic of polymerizations that include crosslinkers that can form 2- or 3-dimensional networks. For example, the condensation of a dicarboxylic acid and a
triol
In chemistry, a triol is a chemical compound containing three hydroxyl groups ( functional groups),diol will not. The gel is often a small percentage of the mixture, even though it greatly influences the properties of the bulk.
Mathematical definition
An infinite polymer network appears at the gel point. Assuming that it is possible to measure the extent of reaction, ''p'', defined as the fraction of
monomer
In chemistry, a monomer ( ; '' mono-'', "one" + ''-mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization.
Classification
...
s that appear in
cross-link
In chemistry and biology a cross-link is a bond or a short sequence of bonds that links one polymer chain to another. These links may take the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural ...
s, the gel point can be determined.
The critical extent of reaction for the gel point to be formed is given by:
:
For example, a polymer with N≈200 is able to reach the gel point with only 0.5% of monomers reacting. This shows the ease at which polymers are able to form infinite networks.
The critical extent of reaction for
gelation
In polymer chemistry, gelation (gel transition) is the formation of a gel from a system with polymers. Branched polymers can form links between the chains, which lead to progressively larger polymers. As the linking continues, larger branched p ...
can be determined as a function of the properties of the monomer mixture, r, ρ, and f:
:
See also
*
Pour point
The pour point of a liquid is the temperature below which the liquid loses its flow characteristics.
It is defined as the minimum temperature in which the oil has the ability to pour down from a beaker. In crude oil a high pour point is generall ...
*
Cold filter plugging point Cold filter plugging point (CFPP) is the lowest temperature, expressed in degrees Celsius (°C), at which a given volume of diesel type of fuel still passes through a standardized filtration device in a specified time when cooled under certain con ...
*
Petroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...
References
Further reading
*{{cite book, authors=Rudin, Alfred and Choi, Phillip, title=The Elements of Polymer Science and Engineering, 3rd Edition, year=2012, publisher=Elsevier Science, page=410, isbn=9780123821782
Polymer physicsChemical properties