Sodium Deoxycholate Modiifed Graphene And Its Composites With Polymers

Graphene, as the thinnest carbonaceous material, is an atom thick, two-dimensional planarsheet with carbon atoms arranged in a honeycomb lattice. Graphene with such specialstructure possesses many excellent properties, such as high mechanical strength, excellentelectrical conductivity and thermal conductivity, high theoretical specific surface area and soon. Therefore, graphene has attracted tremendous attention from both experimental andtheoretical communities since it was found in the year of2004. Now graphene has beenapplied in many fields, such as polymer composites, optoelectronic and biomedical materialsand so on. The polymer/graphene composites have been one of the most important directionsfor the potential applications of graphene.In our study, we prepared the modified graphene (SDC-G) with graphene oxide (GO) as theprecursor and sodium deoxycholate (SDC) as the modifier. Then SDC-G was added inpolyvinyl alcohol (PVA) and epoxidized natural rubber (ENR) to fabricate the PVA/SDC-Gand ENR/SDC-G composites, respectively. The structures and properties of the compositeswere characterized. We mainly discussed the interactions between graphene and polymers,and the dispersion state of graphene in polymers. The performance of the polymer/graphenecomposites were correlated with the interfacial interactions and the dispersion state ofgraphene. The main conclusions were described as follows.(1) GO was successfully prepared via modified Hummers method. Compared with GO, theoxygen content of SDC-G was greatly reduced, and the electrical conductivity reached308S/m. Most of graphene in SDC-G colloid was single-layered and the concentration in thecolloid was as high as20mg/ml. The interactions between graphene and SDC were disclosedto be hydrogen bonding, hydrophobic interaction and electrostatic repulsion.(2) The PVA/SDC-G composites were prepared via solution casting. It was found thatSDC-G was well exfoliated in PVA matrix, and the main interaction between PVA and SDC-Gwas proposed to be hydrogen bonding. The addition of graphene greatly enhanced themechanical properties of PVA. For example, when the SDC-G content was1wt%, the stressstrength and the modulus of the PVA/graphene composite were2-folded and4-foldedcompared with pure PVA, respectively. (3) The ENR/SDC-G composites were prepared by co-coagulating the mixture of theSDC-G suspension and ENR latex. It was found that SDC-G was well dispersed in ENRmatrix. The main interfacial interaction between ENR and SDC-G was also proposed to behydrogen bonding. The incorporation of SDC-G could obviously enhance the modulus of theENR. The thermal stability and thermal conductivity were also increased in some extent.