Spherically propagating thermal polymerization fronts

Abstract

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.

Frontal Polymerization

“…Binici et al developed a system that was a gel created by the base-catalyzed reaction of a trithiol with a triacrylate, in which a peroxide was also dissolved [110]. The gel was necessary to suppress convection.…”

Hydrogels for Potential Colon Drug Release by Thiol‐ene Conjugate Addition of a New Inulin Derivative

“…The strategies employed to obtain chemically crosslinked hydrogels are numerous, from conjugation of a polymer functional group with a complementary reagent, [14] to UV induced crosslinking of acrylic functionalized polymers, [4,5,15] to addition of electron bearing moieties (such as thiol, amine or nitrile groups both bi or multifunctional), to acceptor molecules such as acrylic or vinyl sulfone groups. [16][17][18][19][20][21][22][23] In particular, the vinyl sulfone group is receiving growing attention, in organic synthesis, as a selective electron acceptor in the formation of new heteroatom/carbon bonds. Many examples in the literature place the accent on the conjugate addition of thiol groups to unsaturated groups such as acrylic and vinyl sulfone, for the production of hydrogels, by using both bi-or multifunctional thiolbearing molecules.…”

“…[24] Among the reagents used for this purpose, trimethylolpropane tris(3-mercaptopropionate) (TT) shows interesting properties in terms of reactivity and the physicochemical features of the final product after addition of its thiol moieties to p systems. [18,[25][26][27][28] In this work, we report the synthesis of new biocompatible, stimulus sensitive and biodegradable hydrogels, obtained by derivatizing inulin (INU) with divinyl sulfone (DV) and succinic anhydride (SA), then by crosslinking the resulting INUDVSA derivative with TT. In particular, the choice of inulin as a starting polymer was based on the peculiar properties of this polysaccharide; it is specifically degraded into the colon, non-toxic (including its degradation products), shows a prebiotic effect on the intestinal bacterial population, is widely used in the food industry, is FDA approved and has been proposed as a starting material for the production of drug delivery systems.…”

First solvent‐free synthesis of poly(N‐methylolacrylamide) via frontal free‐radical polymerization

“…Crivello and coworkers reported on photoinitiated cationic FP,35, 36 and Mariani et al described UV‐ignited frontal epoxy curing 37. Binici et al presented in 2006 the first spherically‐propagating polymerization 38. Chen and coworkers prepared epoxy resin/polyurethane hybrid networks and urethane–acrylate copolymers 39, 40…”