Water-Soluble Branched Polyacrylamides Prepared by UV-Initiated Polymerization Using a Novel Kind of Water-Soluble Macromolecular Photoinitiator

Abstract

Branched polyacrylamides (PAMs) have shown tremendous potential in wastewater treatment, papermaking, and oil drilling due to their unique molecular structure, remarkable shear stability, and effective flocculability. Efficient approaches for their industrial-scale production have attracted increasing attention. Herein, we report a facile, scalable, highly efficient, and cost-effective strategy for the production of branched PAMs through UV polymerization of acrylamide (AM) initiated with a novel water-soluble macro-photoinitiator. Through precipitation copolymerization of AM and 2-hydroxy-1-[4-(2-acryloyloxyethoxy)­phenyl]-2-methyl-1-propanone (M2959), poly­(AM-co-M2959)­s bearing photoinitiator moieties on the backbone were successfully synthesized, which showed excellent water solubility and high photoinitiation efficiency. Most importantly, both the branching degree and main-chain length of the branched PAMs were controllable, given that the molar mass and photoinitiating group content of poly­(AM-co-M2959)­s could be effectively controlled by adjusting the monomer feed ratio of AM/M2959. The rheological properties of the resultant branched PAMs were characterized in detail, and excellent water solubility and shear resistance were observed, confirming the well-defined branched structure of the as-prepared PAMs. Due to their facile synthesis, simplicity of operation, and high photoinitiation efficiency, these novel macro-photoinitiators have great potential as a versatile platform for the preparation of various branched polymers containing different functional groups (not limited to branched PAMs).

Highly Conductive, Transparent, Adhesive, and Self‐Healable Ionogel Based on a Deep Eutectic Solvent with Widely Adjustable Mechanical Strength

“…Fabrication of PEI/PAA/CMC-CCl-U Ionogel: As described in our previous work, polymerizable photoinitiator was synthesized via the reaction of commercial photoinitiator Irgacure 2959 with acryloyl chloride, designated as AC-2959. [36] PEI/PAA/CMC-CCl-U ionogels were facilely prepared via a one-step photopolymerization of AA initiated by AC-2959. Typically, CCl (5.58 g, 0.04 mol) and urea (4.8 g, 0.08 mol) were firstly mixed and stirred at 80 °C for 90 min to form the CCl-U DES, and then 0.104 g CMC was dissolved in CCl-U to form a homogeneous solution.…”

“…The polymerizable photoinitiator AC-2959 was synthesized via the reaction of acryloyl chloride with a commercial photoinitiator, 2-Hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959). [36] As depicted in Figure 1, the one-step in situ photopolymerization of AA was efficiently initiated by AC-2959, resulting in PAA/PEI composite ionogels possessing both physically and chemically cross-linked networks. The physically crosslinked network was mainly formed by electrostatic and hydrogenbonding interactions.…”

Recent advances on water-soluble photoinitiators of polymerization

“…[293] However, most of these photoinitiators could only be activated in the UV range. [263,[294][295][296][297][298][299][300] Still based on this strategy, a water-soluble derivative of 2-hydroxy-2-methyl propiophenone (Irgacure 1173) was recently proposed in the literature (See Figure 12). [301] This photoinitiator could notably initiate the polymerization of a benchmark organosoluble methacrylate resin (bisphenol A-glycidyl methacrylate (BisGMA)/triethylene glycol dimethacrylate (TEGDMA) (70/30 w/w) upon irradiation at 385 nm and under air in the presence of N-heterocyclic carbene borane as an additive.…”