Synthesis and characterization of pH‐responsive water‐dispersed nanohydrogels of cross‐linked polyacrylamide‐co‐polyacrylic acid

Abstract

In the following article, stable nanohydrogels (NHGs) of poly (acrylamide-coacrylic acid) (PAAm-co-PAA) were synthesized by batch polymerization (BP) and semicontinuous (SP) polymerization processes. As crosslinking agents, N,N 0 -methylenebisacrylamide (NMBAM) and ethylene glycol dimethacrylate (EGDMA) were used; docusate sodium salt (AOT) was used as a surfactant. The initiators employed in this work were 2,2 0 -Azobis(2-methylpropionamidine) dihydrochloride (V-50), potassium peroxydisulfate (KPS), peroxydisulfuric acid diammonium salt (APS), and dibenzoyl peroxide (BPO). The compositions of acrylamide/acrylic acid (AAm/AA) (90/10, 70/30, 50/50, w/w), the type of a crosslinking agent, and the type of initiator on pH response of water-dispersed NHGs were investigated. The NHGs were characterized by dynamic light scattering (DLS). Latexes with average particle size (Dpz) from 53 to 125 nm were obtained using NMBAM and EGDMA by BP polymerization processes. In contrast, NHGs synthesized by SP polymerization processes showed a Dpz ranging from 73 to 125 nm using NMBAM and EGDMA. On the other hand, the Dpz of the NHGs dispersed in water was found to be from 126 to 302 nm with NMBAM and EGDMA, respectively. Furthermore, the Dpz of the NHGs depended on the pH; higher pH values produced high Dpz values. The spherical morphology was maintained at the studied pH.

A Research Progress of CO-Responsive Plugging Channeling Gels

“…However, it is not convenient for underground use and is generally employed in the preparation of pre-crosslinked gel particles. The other double-bond crosslink agent is BACy, It is often used as a crosslinking agent to adsorb dyes and sewage materials with strong stability, incompatible with strong oxidants, and insoluble in water [58,59]. This article investigates CO 2 -responsive gel particles of different sizes.…”

Using polyacrylamide hydrogel to adsorb chloride ions in cement-based materials

“…4(a) and (b), it could be seen that the change of monomer content had less effect on the chlorine ions adsorption of PAM gel than the change of crosslinker content. [33][34][35][36][37][38][39]…”