Study on Thermo- and pH-sensitive Hydrogels Constructed Using Block Copolymers of Poly(N-isopropylacrylamide) and Guar Gum

Aim Thermo- and pH-sensitive hydrogels were synthesized using N-isopropylacrylamide and Guar gum (GG) and crosslinked with gluteraldehyde (GA). The character of hydrogels was discussed in detail. Methods The effect of temperature, iron strength and crosslinker on the property of hydrogels was studied. Results Elasticity and EDS decreased with increasing amounts of NaCl and crosslinker. When the temperature was below the LCST, the release mass of water in the GPNA hydrogel increased with the time1/2; when the temperature was above the LCST, the GPNA hydrogel shrank slonsly before quicking increasing with the destruction of the structure of the hydrogel. With the increase of NaCl, the water-losing rate of GPNA hydrogel increased, and the shrinkability was strengthened. When the temperature was lower or higher than LCST, the flow of hydrogel was pseudoplastic flow or dilatant flow. With the increase of GA content, the flow of hydrogel changed from dilatant flow to pseudoplastic flow. Conclusion GPNA hydrogels are thermo-sensitivie and iron-strength sensitive.