Study on inverse suspension polymerization of acrylamide with Tween as dispersant
摘要
In this study, polyacrylamide superabsorbent resin was synthesized via inverse suspension polymerization, with hydrophilic Tween as dispersant, acrylamide as monomer, ammonium persulfate as initiator and N, N’-methylenebisacrylamide as crosslinking agent. The as-prepared products presented uniform fine particle morphology. The single-factor variable method was adopted to systematically investigate the influences of dispersant dosage, crosslinking agent content, initiator dosage, monomer concentration, oil-to-water ratio, reaction temperature and reaction time on water absorption capacity and product yield, so as to determine the optimal synthesis conditions. The experimental results revealed that under the optimal conditions including 6% Tween dosage, 0.15% N, N’-methylenebisacrylamide, 0.5% ammonium persulfate, monomer concentration of 20%~25%, oil-to-water ratio of 4:1 ~ 6:1, reaction temperature of 70 °C and reaction time of 4 ~ 4.5 h, the water absorption capacity of polyacrylamide resin reached 26.90 g/g and the yield was over 97%. The morphology, chemical structure, thermal stability and molecular weight distribution of the samples were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, 1H NMR measurement, thermogravimetric analysis and gel permeation chromatography, and the effect of internal crosslinked structure on comprehensive properties was further discussed. The results verified that the synthesized polyacrylamide possessed definite chemical structure, and its internal crosslinked network structure effectively improved the thermal stability and molecular weight characteristics of the material.