Dual-Reactive Hyperbranched Polymer Synthesis through Proton Transfer Polymerization of Thiol and Epoxide Groups

Abstract

A new synthesis of hyperbranched polymers through proton transfer polymerization of thiol and epoxide groups is presented. For this, an AB 2 monomer bearing two epoxides and a thiol groups is synthesized. Base-catalyzed proton transfer polymerization of this monomer led to the formation of a polythioether-based hyperbranched polymer with a 65−69% degree of branching and carrying about 2% of disulfide-based structural defects. This polymer contained two reactive sites, a hydroxyl group and an epoxide unit, distributed throughout the branched scaffold. The epoxide groups could be employed in anchoring an alkyl, aryl, or ethylene oxide chain through a thiol−epoxy reaction, while the hydroxyl groups produced during the polymerization and the first functionalization reactions could be engaged in attaching positively charged primary ammonium groups to the branched backbone. These sequential postpolymerization modifications transformed the general dual-reactive scaffold into dual-functionalized hyperbranched materials with potential utility in the arena of gene delivery applications.

Hyperbranched Polymers by Light‐Induced Self‐Condensing Vinyl Polymerization

“…The same strategy has also been implemented for the synthesis of hyperbranched polyesters and porphyrins . Later on, Khan et al developed the HTP of H‐AB 2 monomer including two epoxides and a thiol group to synthesize a polythioether‐based HBP …”

Kinetics of the epoxy–thiol click reaction initiated by a tertiary amine: Calorimetric study using monofunctional components

“…In this case, the reaction proceeds through a typical nucleophilic ring opening reaction. The base generates thiolate anions (RS − ) which give the reaction product by the following propagation/proton transfer reactions [12,16]:…”

Enhancement in the Glass Transition Temperature in Latent Thiol-Epoxy Click Cured Thermosets

“…These characteristics have allowed for the discovery of innovative solutions in the field of coatings technology [4,5]. Among click reactions, thiol-epoxy systems have broad applications [6][7][8][9][10][11] but they present an important drawback which is the low reactivity of the formulation that requires the addition of a catalyst. However, the disadvantage of a too short pot-life appears on catalysing with amines [12].…”