Free‐Radical Frontal Copolymerization: The Dependence of the Front Velocity on the Monomer Feed Composition and Reactivity Ratios

Abstract

Frontal copolymerization is a process in which a spatially localized reaction zone propagates into a mixture of two monomers, converting them into a copolymer. In the simplest case of free‐radical copolymerization, a mixture of monomers and initiator is placed into a test tube. Reaction is initiated at one end of the tube, and a self‐sustained thermal wave, in which chemical conversion occurs, develops and propagates through the tube. We develop a mathematical model of the frontal copolymerization process and analytically determine the structure of the polymerization wave, the propagation velocity, maximum temperature, and degree of conversion of the monomers. Specifically, we examine their dependence on reactivity ratios as well as other kinetic parameters, monomer feed composition, and exothermicity of the reactions. Our analytic results are in good quantitative agreement with both direct numerical simulations of the model and experimental data, which are also presented in the paper.Dependence of front velocity on monomer feed composition for different heat release parameters.imageDependence of front velocity on monomer feed composition for different heat release parameters.

Nonlinear Dynamics of Frontal Polymerization with Autoacceleration

“…Therefore, this technique can been used to determine approximate solutions for frontal polymerization. In fact, it has been used to study FP problems yielding accurate results [8,[11][12][13][14].…”

“…We have chosen the temperature T * i in such a way that the step function K i (T ) and the Arrhenius function k i (T ) have approximately equal integral values over the interval T 0 < T < T b . In particular, integrating the function in (13) gives…”

Frontal Polymerization Synthesis of Starch‐Grafted Hydrogels: Effect of Temperature and Tube Size on Propagating Front and Properties of Hydrogels

“…[5] The application of FP to synthesize copolymers has been investigated. [6][7][8] Recently, FP was used by Fiori and Mariani for the synthesis of polyurethane, [9] by McFarland and Pojman for the polymerization of 1,6-hexanediol diacrylate with a microencapsulated initiator. [10] In these examples, the rapid reaction rate, observed in propagating fronts, circumvents phase separation which occurs commonly in batch studies.…”

Frontal atom transfer radical polymerization of tri(ethylene glycol) dimethacrylate

“…FP has also been exploited to prepare materials containing liquid crystals dispersed in polymeric matrices (both as film and other thicker materials) [9,10]. In recent years our group has focused on the extension of the number of monomers that can be polymerized by way of FP and on applying this technique to other mechanisms of both chain and step-growth polymerizations.…”