Studies on Graft Copolymerization of 2-Acrylamido-2-methylpropanesulfonic Acid onto Protein Initiated by Ammonium Persulfate

Abstract

The protein, collagen, has been chemically modified by graft copolymerization of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) in an aqueous medium using ammonium persulfate as an initiator under argon atmosphere. A plausible reaction mechanism of grafting has been suggested. Evidence of grafting was obtained by comparison of FTIR spectra of collagen and homopolymer-free collagen-gpoly(2-acrylamido-2-methylpropanesulfonic acid) as well as solubility characteristics and gravimetric analysis of the products. Evidence of grafting was obtained by comparing FTIR, thermogravimetric curves of collagen and the graft copolymer as well as solubility characteristics of the products. The synthetic conditions were systematically optimized through studying the influential factors including temperature, concentration of the initiator, 2-acrylamido-2-methylpropanesulfonic acid monomer and collagen substrate.

Preparation and Characterization of Protein-Based Hydrogel: Cottonseed Protein Grafted with 2-Acrylamido-2-Methylpropanesulfonic Acid (AMPS)

“…Ten, the anion radicals abstract hydrogen from one of the functional groups (i.e., COOH, SH, OH, and NH 2 ) in side chains of the protein backbones to form corresponding macroinitiators. Tese macroradicals initiate the grafting of AMPS onto protein backbones leading to a graft copolymer [45]. Figure 4 shows the grafting of AMPS onto protein backbones.…”

“…From the representative of FTIR spectra of AMPSg-CSP, the peaks at 1630 cm −1 were attributed to amide I to C�O stretching in carboxamide functional groups of the protein backbone. AMPS-g-CSP shows absorption peaks at 3435 cm −1 due to the collapse of -NH and -OH (-SO 3 H) stretching frequency of AMPS and due to overlapping contributions of the stretching vibrations of both O-H and N-H Advances in Materials Science and Engineering groups of the protein backbone [45]. Te protein-g-AMPS hydrogel comprises a protein backbone with side that carry sulfate groups that are evidenced by a new characteristic absorption band around 1200 cm −1 .…”