Preparation And Characterization Of Graphene Oxide Nanocomposite Hydrogel

Hydrogel, a typical soft and wet matter, consisted of cross-linked polymers and a large amount of water. Owing to their capability of environment stimuli, high permeability and similarity with tissues, hydrogels have attracted attentions in applications in many areas. But defects of hydrogel on mechanical strength and over-reliance on the monomers’characteristics have limited the wide range of application.Nanocomposite hydrogel(NC), with nanoparticles working as physical crosslinking sites, has attracted many attentions with its high mechanical strength and properties. As one of the most interested nanoparticles, graphene has also been applied to optimize the network of hydrogel.In this article, graphene oxide(GO) was prepared by modified Hummers’ method. As-prepared GO was dispersed in the double network. SEM and compression test were used to evaluate the influence of GO. It appears that the GO, physical crosslinked by polymer chains, tend to reunite to decrease surface energy. The reunited GO became the defects in the hydrogel, which decrease the fracture stress of double network. The fracture stress of C010 (10wt% GO) decreased to 1.28MPa while C000 (pure DN)remained 2.33MPa. The reduction experiments showed that only hydrazine hydrate could achieve the good reduction effect while keeping the DN available. The rG0-DN did not show the obviously increase in conductivity.In order to achieve the better dispersion of GO in monomer solution, we prepared modified GO(GOM) with methacryloyl chloride. GOM was dispersed with surfactant to avoid the reunion in HEMA-co-AAm. The results showed that GOM successfully increased the compressive strength, and SDS not only optimized the dispersion of GOM, but also increased the swelling degree.In order to enhance the compressive strength of the chemical crosslinked HEMA-co-AAm hydrogel by GOM, we introduced DCC-DMAP as catalyst to improve the acylated degree (NGOM). We use sodium oleate to replace SDS in order to disperse the NGOM uniform in monomer solution. As-prepared hydrogel (HSG) achieve 2MPa in compression test, achieved similar mechanical strength(2.3MPa) of DN.