Synthesis, characterization, and swelling behavior of poly(N-hydroxymethylacrylamide) grafted poly(vinyl alcohol)

Abstract

In this study, the graft copolymerization of N-hydroxymethylacrylamide (NHMAAm) with poly(vinyl alcohol) (PVA) was carried out by using potassium persulfate/N,N,N,N-tetramethylethylenediamine (K2S2O8) to improve physicochemical properties and functionality of PVA. The structures of PVA-g-poly-NHMAAm (PNHMAAm) copolymers were characterized by Fourier transform infrared, elemental analysis, nuclear magnetic resonance (H-1-NMR), C-13-NMR, and size exclusion chromatography. Their thermal behaviors were investigated by differential scanning calorimetry and thermogravimetric analysis (TGA). The TGA results indicated that the graft copolymers show better thermal stability then PVA. The effects of reaction time, temperature, NHMAAm, and K2S2O8 concentrations on grafting parameters were examined. The maximum grafting yield (34.01%) was provided when reaction was carried out under optimum conditions (time = 2 hr, T = 40 degrees C, [NHMAAm] = 0.25 M, [K2S2O8] = 4.56 x 10(-3) M). Moreover, PVA-g-PNHMAAm membranes were prepared and their swelling behaviors were studied. The results demonstrated that swelling degree of graft membranes increased almost 3.5-fold compared to PVA membrane.