Optimal Preparation And Properties Of Graphene/Acrylic Ester Polymer Composites

In the present dissertation, we have summarized the recent progress of graphene/polymer composites. Two kinds of graphene/polymer composites have been successfully prepared, and their morphologies, thermal and mechanical properties have been investigated.Covalently-functionalized graphene (FG) was successfully obtained by grafting3-isopropenyl-α, α’-dimethyl benzyl isocyanate (m-TMI) to graphene oxide (GO) followed by chemical and solvothermal reduction of GO. FG sheets were hydrophobic and stable in polar solvents such as N, N-dimethylformamide. Reactive vinyl-benzyl groups of m-TMI attached to FG were copolymerized in-situ with methyl methacrylate to produce graphene/poly(methyl methacrylate)(PMMA) composites. FG sheets were homogeneously dispersed in PMMA and form strong interface bonding with the matrix, thus contributing to large increases in elastic modulus (+72.9%) and indentation hardness (+51.2%) at1wt%loading. Incorporation of FG into PMMA also changed its elastic-plastic behavior and hence, a decrease of plasticity index and an increase of recovery resistance were observed for the resulted composites by increasing the portion related to the elastic work. Besides, the onset decomposition temperature and glass transition temperature of neat PMMA increase by100℃and12.7℃, respectively, by addition of1%FGCore-shell latex nanoparticles consisting of a PBA core and a PMMA shell were synthesized by a two-stage emulsion polymerization technique. Incorporation of graphene oxide (GO) aqueous solution into the PBA-PMMA latex successfully fabricated GO/PBA-PMMA and RGO/PBA-PMMA composites by in-situ reduction of GO. TEM and the particle size distribution manifest an effective polymerization of MMA around PBA core. DSC curve shows that the adding of GO and graphene slightly increases Tgs of the two phases in PBA-PMMA core-shell nanoparticle. The obtained polymer composites exhibit a characteristic of baroplastics and could be processed at ambient temperature by compression molding. With the increase of pressure and processing time, the young’s modulus and yield strength of each material has improved, thus, the mechanical properties of the composite material could be improved by increasing the pressure or processing time. TEM images of cryo-microtomed by compression molding composites shows GO have better dispersion than graphene in polymer matrix.