The Preparation And Study On Performance Of Superabsorbent Nanocomposites Based On Graphene Oxide

In this paper, graphite oxide was prepared using a modified Hummers method, and then was subjected to ultrasonic treatment in water to prepare graphene oxide (GO) whose solubility in different solution and organic solvents were investigated. By employing GO nanoplatelets as fillers, poly(acrylic acid)-GO (PAA-GO) and poly(acryl amide)-GO (PAM-GO) superabsorbent nanocomposites were synthesized by a facile solution polymerization using N,N-dimethylformamide as crosslinker and ammonium persulfate as initiator. Water absorbency, water retention ability and salt tolerance of resulting materials were also discussed.GO and composites were characterized by means of X-ray diffraction (XRD), IR spectra (IR), Scanning electron microscope (SEM), Atomic force microscopy (AFM) and Thermal gravimetric analyzer (TGA). The analysis results of XRD, IR and SEM showed that graphite oxide was successfully prepared by modified Hummers and GO platelets in nanoscale were obtained after ultrasonic treatment by AFM analysis. GO could form stable dispersion in pure water which attributed to the natural hydrophilicity and the electrostatic repulsion apparently as a result of ionization of the carboxylic acid and phenolic hydroxyl groups which existed on the GO sheets. In the test for solubility, it was observed that GO had a better solubility in organic solvents which was attributed to that GO sheets were thought to be heavily decorated with polar oxygen-containing functionalities such as hydroxyl and carboxyl which should promote a good interaction between GO sheets and solvent.The analysis results of XRD, IR and SEM showed that GO nanoplatelets were well dispersed throughout polymer matrix as individual nanoplatelets and no obvious aggregation was observed. TGA demonstrated that the adding of GO into the matrix had an apparent influence on the thermal stability. The introduction of GO to poly(acrylic acid)(PAA) network resulted in a decrease in thermal stability, while an increase in thermal stability was observed when introducing GO nanoplatelets into the ploy(acryl amide)(PAM) network.To investigate the water absorbencies, compared with PAA and PAM, there was a greatly increase in water absorbencies for the composites. PAA-GO exhibited a water absorbency of508g g-1, which was nearly as many again as that of PAA superabsorbent. The water absorbency of PAM-GO reached to400g g-1which was nearly two times of that of PAM. Water retention of the swollen superabsorbent composites and the salt tolerance of the dry composites were improved apparently compared with PAA and PAM.