Solvent-free synthesis of polyacrylamide by frontal polymerization

Abstract

Polymerization and characterization of polyacrylamide prepared by frontal polymerization are described. Frontally polymerized polyacrylamide is imidized and crosslinked during polymerization. Imide formation was determined by elemental analysis. The addition of commercial polyacrylamide or barium carbonate to the monomer (acrylamide) and initiator (potassium persulfate) decreased the reaction temperature from 235 °C to < 100 °C, thereby reducing imide formation. The commercial polyacrylamide‐diluted product, frontally polymerized polyacrylamide‐diluted product, and the barium carbonate‐diluted product were characterized by IR, TGA, and elemental analysis. Molecular weights of barium carbonate‐diluted samples were determined by light scattering and found to be on the order of one million. Conversion of the barium carbonate‐diluted product was determined to be 76 ± 6%, independent of the amount of diluent over the range 0.8:1–1.5:1. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1129–1135, 2000

Frontal Polymerization

“…Spin modes have also been observed in the FP of transition-metal nitrate/ acrylamide complexes [50,52], which are solid, but were not observed in the frontal acrylamide polymerization system [53].…”

“…Fortenberry and Pojman studied FP of acrylamide without solvent using powdered acrylamide and persulfate [53]. They found that the initial or ''green'' density of the systems affected the front velocity.…”

Water‐Triggered Frontal Polymerization

“…In a few reactions, the central core was nearly charred due to very high temperature there. The extent of imidization was found to be 6-8%, confirming that reported by Pojman et al [11] Elemental analysis showed the presence of traces of sulfur indicating that termination is through disproportionation. [18] Polymer yields were 75 AE 5% and 85 AE 5% in Set I and Set II, respectively.…”

“…Fortenberry and Pojman have tried to solve this problem by adding fillers (barium carbonate) to the reaction mixture. [11] We have come up with a new method for the prevention of imidization, to yield commercially pertinent soluble, linear polyacrylamide. Exotic patterns formed in FP can be investigated as nonlinear phenomena.…”

Hybrid Polymer-Immobilized Nanosized Pd Catalysts for Hydrogenation Reaction Obtained via Frontal Polymerization

“…According to XPS data, the basic line in Pd3d5/2-spectrum of polymerization product (Figure 2) is characterized by bond = 336.5 eV, which is higher than bond in Pd0 (33�.0 eV) because of formation of �ne particles of Pd 0 and Pd [9,23]. Increase in bond of basic line in the N1s spectrum from 399.8 to 401.7 eV is probably caused by the reaction of cyclization of polymer chains and formation of imide groups [24] (see Scheme 1).…”