Spherically propagating thermal polymerization fronts

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2006-02, Vol.44 (4), p.1387-1395
• Main Authors: Binici, Burcu, Fortenberry, Dionne I., Leard, Kayce C., Molden, Marcus, Olten, Nesrin, Popwell, Sam, Pojman, John A.
• Format: Article
• Language: English
• Subjects: addition polymerization; Applied sciences; Exact sciences and technology; frontal polymerization; kinetics (polym.); networks; Physicochemistry of polymers; Polymerization; Polymers and radiations; spin modes; thiol-ene
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.21246

We demonstrate for the first time spherically propagating frontal polymerization that also exhibits spin modes. We have developed an interesting system using the amine‐catalyzed Michael addition of a trithiol to a triacrylate to create a rubbery gel. The gel suppresses convection and bubble formation during front propagation. A peroxide is also present to act as a thermal initiator. The front propagates via free‐radical polymerization of the remaining triacrylate after being initiated photochemically in the center of the reactor. It is possible to prepare the rubbery gel in any shape and then initiate thermal frontal polymerization. So‐called spin modes have been observed for the first time in spherically propagating fronts in which waves of polymerization propagate on the expanding spherical front. A system using a diacrylate dissolved in dimethyl sulfoxide with added silica gel and with persulfate as the initiator supports spherical fronts but does not exhibit spin modes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1387–1395, 2006 A front of polymerization is propagating from a site of photochemical initiation. The system consists of a gel created by the amine‐catalyzed thiol addition of a trithiol to a triacrylate in a 1:4 ratio. The remaining triacrylate supports thermal frontal polymerization via a peroxide initiator.