Synthesis and properties of thermo-responsive guar gum/poly(N-isopropylacrylamide) interpenetrating polymer network hydrogels

Thermo-responsive guar gum (GG)/poly(N-isopropylacrylamide) (PNIPAAm) hydrogels with interpenetrating polymer networks (IPN) were synthesized. The influence of chemical compositions on the preparation, thermal responsibility and swelling behavior was investigated with the help of IR, DSC and SEM technologies. The introduction of GG component could reduce the total solid weight needed for gel formation from 43.5 to 20.0 g/L and lower the final water retentions from 19.4% to 2.7%. The thermo-responsive GG/PNIPAAm IPN hydrgels with different response rates can be prepared by modifying the proportion of GG to NIPAAm. Compared with pure PNIPAAm hydrogels, GG/PNIPAAm hydrogels with reversible thermo-responsive characteristics exhibited faster deswelling rates and lower water retentions at low GG content (below 15 wt%). The introduction of GG component with IPN technology could improve the temperature sensitivity and permeability of GG/PNIPAAm IPN hydrogels which could be expected as good candidates for the controlled drug delivery system with both thermo-responsive and specific-colonic drug release behaviors.