Semi-interpenetrating polymer networks based on crosslinked poly(N-isopropyl acrylamide) and methylcellulose prepared by frontal polymerization

In this work, semi-interpenetrating gels of poly(N-isopropyl acrylamide) and methylcellulose were successfully synthesized by using the Frontal Polymerization (FP) technique. The gels were obtained in the presence of dimethyl sulfoxide and trihexyltetradecylphosphonium persulfate, as polymerization solvent and radical initiator, respectively, hence avoiding the formation of bubbles during polymerization. Then, some of the gels containing dimethyl sulfoxide were thoroughly washed with water, hence obtaining the corresponding hydrogels. The effects of the ratio between poly(N-isopropyl acrylamide) and methylcellulose, the amount of crosslinker and solvent medium (i.e. dimethyl sulfoxide and water) were thoroughly studied, assessing the influence of temperature and velocity of FP fronts on the glass transition temperature values (dried samples), on the swelling behavior and on the dynamic-mechanical properties (gels swollen both in water and dimethyl sulfoxide).