Ceiling temperature

Ceiling temperature (${\displaystyle T_{c}}$) is a measure of the tendency of polymers to revert to their monomers. When a polymer is at its ceiling temperature, the rate of polymerization and depolymerization of the polymer are equal. Generally, the ceiling temperature of a given polymer is correlated to the steric hindrance of the polymer’s monomers. Polymers with high ceiling temperatures are often commercially useful.

At constant temperature, the reversibility of polymerization can be determined using the Gibbs free energy equation:

where ${\displaystyle \Delta S_{p}}$ is the change of entropy during polymerization. The change of enthalpy during polymerization, ${\displaystyle \Delta H_{p}}$, is also known as the heat of polymerization, which is defined by

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