4. Conclusion
In summary, an eco-friendly hybrid SAR with well dispersed GO sheets was synthesized through in situ copolymerization of partially neutralized AA on CMC backbone in the presence of GO as fillers. It was found that the contents of various factors, such as GO, CMC, cross-linking agent, neutralized degree ofAAand initiator had significantinfluence on the water absorbency and retention behaviors. Under the optimized conditions viz. AA= 7.2 g, neutralization degree = 80%, APS = 0.5 wt%, CMC = 12 wt%, GO = 0.6 wt%, reaction temperature 70 ◦C, and MBA= 0.05 wt%, the water absorbency of CMC-g-PAA/GO HSAR in distilled water and 0.9 wt% NaCl solution were 750 g g−1 and 85 g g−1, respectively. According to the results of XRD and SEM, the incorporation of GO sheets had almost no obvious influence on the inherent structure of the SAR but changed the surface morphology markedly. Importantly, the thermal stability, water absorbency and retention ability of the resultant HSAR improved obviously compared to the pure SAR. Moreover, the CMC-g-PAA/GO HSAR could retain relatively higher swelling capacity under weak acidic and basic conditions although pH-sensitive swelling behavior. Thus, this kind of hybrid SAR, combining the excellent characteristics of SARs with the unique properties of GO, may find widespread use in a variety of practical applications.
