ABC-Type Triblock Copolyacrylamides via Copper-Mediated Reversible Deactivation Radical Polymerization.

Fehaid M Alsubaie,Othman Y Alothman,Abdel-Hamid I Mourad,Hassan Fouad

doi:10.3390/polym14010116

Abstract

The aqueous Cu(0)-mediated reversible deactivation radical polymerization (RDRP) of triblock copolymers with two block sequences at 0.0 °C is reported herein. Well-defined triblock copolymers initiated from PHEAA or PDMA, containing (A) 2-hydroxyethyl acrylamide (HEAA), (B) N-isopropylacrylamide (NIPAM) and (C) N, N-dimethylacrylamide (DMA), were synthesized. The ultrafast one-pot synthesis of sequence-controlled triblock copolymers via iterative sequential monomer addition after full conversion, without any purification steps throughout the monomer additions, was performed. The narrow dispersities of the triblock copolymers proved the high degree of end-group fidelity of the starting macroinitiator and the absence of any significant undesirable side reactions. Controlled chain length and extremely narrow molecular weight distributions (dispersity ~1.10) were achieved, and quantitative conversion was attained in as little as 52 min. The full disproportionation of CuBr in the presence of Me6TREN in water prior to both monomer and initiator addition was crucially exploited to produce a well-defined ABC-type triblock copolymer. In addition, the undesirable side reaction that could influence the living nature of the system was investigated. The ability to incorporate several functional monomers without affecting the living nature of the polymerization proves the versatility of this approach.

Highlights

The homo-polymers and copolymers of acrylamide-based monomers have been employed in various applications [1,2,3,4,5]
To the best of our knowledge, only very few publications have reported the controlled diblock copolymerization of acrylamides initiated from poly N-hydroxyethyl acrylamide (PHEAA) or PDMA via reversible deactivation radical polymerization (RDRP) techniques
ABC-type triblock copolymers initiated from a PHEA-based macroinitiator have not yet been reported

Summary

Introduction

The homo-polymers and copolymers of acrylamide-based monomers have been employed in various applications [1,2,3,4,5]. The free-radical polymerization of acrylamide derivatives has been thoroughly investigated, developed controlled free-radical polymerizations have recently been utilized to produce new polymeric materials with unique properties. A few years ago, reversible deactivation radical polymerization (RDRP). The RDRP of acrylamide-based monomers has proven challenging when water is used as the solvent. In aqueous solutions, the rate of the RDRP process is rapid, resulting in termination events. This has been attributed to the lack of equilibrium between the dormant species and the active radical species

Methods

Results

Conclusion