Theory of single-phase solid-state polymerization reactions

A theory of single-phase reactions is developed to explain the isotope, impurity, pressure, and substituent dependence of solid-state polymerization kinetics. This theory, which is applied to diacetylene reactions, incorporates the effect of changing structure during reaction on the rate of chain initiation and the length of propagating chains. The analysis provides a new method for determining chain-length parameters for insoluble and infusible polymers, which utilizes changing ambient measurements during solid-state polymerization. The conversion dependence of activation parameters is derived from elasticity theory for polymerization reactions which produce large dimensional changes in the reaction direction. However, the formulation of reaction kinetics is applicable to a much broader class of solid-state polymerization reactions.