Synthesis and characterization of superabsorbent poly[acrylamide-co-(itaconic acid)]/silica composites

Abstract

A series of superabsorbent polymer synthesized by solution polymerization using a short polymerizing time of for acrylamide (AM) and itaconic acid (IA) monomer via a redox initiator system of 1.0 %wt ammonium persulfate and 0.20 cm³ of N,N,N’,N’-tetramethylethylenediamine, the crosslinking agent of 0.5 %wt N,N’-ethylenebisacrylaminde were carried out with a stirring speed of 250 rpm at the temperature 45◦C for 30min. Silica was used as an inorganic component in the polymerization process to strengthen the copolymer. The synthesized copolymers were dewatered and precipitated by excess methanol and drying at 50◦C in vacuum oven for 24 h. absorption and absorption kinetics behavior of the polymers were investigated. In addition, the water absorbency under load of the synthesized copolymer at 0.28 and 0.70 psi were investigate. The functional groups of copolymer were investigated by Fourier transform infrared spectroscopy, surface morphology by scanning electron microscopy, and thermal properties by differential scanning calorimetry The synthesized copolymer gave the highest water absorbency of 233±8 times its dry weight at the AM-toIA ratio of 97:3, amd could absorb up to 149±2 times its dry weight within 15 min. The highest absorbency under load of the copolymer was 13.2 and 12.1 times its dry weight with 2.0%wt silica at the load of 0.28 and 0.07 psi, respectively. Moreover, the surface morphologies of the copolymer were revealed by SEM technique, which indicated that the porous structure was found in the synthesized copolymer giving the high Tg, which indicated that silica has been incorporated in the copolymer.