A model of frontal polymerization including the gel effect

Abstract

Frontal polymerization is a process in which a spatially localized reaction zone propagates into a monomer, converting it into a polymer. This new approach to polymer production requires both theoretical and experimental study. Agreement between the existing theoretical and experimental work done on this subject has generally been fairly good. However, experimental results tend to show a higher degree of conversion than theoretical results. The reason for this discrepancy may be attributed to an autoacceleration of the polymerization rate which occurs when conversion has reached a certain point. This autoacceleration is due to a decrease in the termination rate caused by a phenomenon known as the gel effect. In this paper, we develop a mathematical model of the frontal polymerization process, taking the gel effect into consideration. Specifically, we determine how it will affect the degree of conversion, maximum temperature, and propagation velocity of the system.

Modified frontal polymerization of poly(methyl methacrylate)

“…A comparison of the PD values for the same TAC values (from 2.54 to 23.6 × 10 −3 M ) for all three methods shows a systematic decrease in σ M w , PD, and σPD from FPGI to FP to SBP (σ FPGI < σ FP < σ SBP ). These observations are mainly due to a more uniform reaction temperature profile from FPGI to FP to SBP, as suggested by modeling studies of FP processes 21, 22…”

“…These observations are mainly due to a more uniform reaction temperature profile from FPGI to FP to SBP, as suggested by modeling studies of FP processes. 21,22 As suggested by Figure 3, in the FP process, each point within the material is polymerized by a wavetype reaction process, 17 in which a relatively low reaction temperature is set and maintained in every section of the material until the reaction front arrives at it and raises the temperature for some time to finally decay approximately to room temperature (see Fig. 1).…”

Mathematical Modeling of Molecular Weight Distributions in Vinyl Chloride Suspension Polymerizations Performed with a Bifunctional Initiator through Probability Generating Functions

“…The reaction rate in the suspension polymerization system can be diffusion‐controlled (gel effect). There are many models available in the literature to describe this effect . These methods account for the gel effect by reducing the termination constant as the conversion and viscosity increase during the reaction .…”

System for the fabrication of polymeric optical fibers

“…Mass polymerization [4][5] is the commonly used system to obtain such preforms in order to guarantee the desired high purity of constituent materials. However, this method has also an intrinsic tendency to produce materials with some sort of inhomogeneities 4,6 , and proper procedures and a smart control are essential to maintain such deviations within accepted limits [6][7] . The main observed inhomogeneities are the presence of immersed or surface bubbles (Fig.…”