| Graphene, as a novel inorganic nanoparticle with unique crystalstructures, has intrigued great interest for its superior mechanical,electrical, thermal and optical properties. Now graphene has beensuccessfully used in various fields, such as sensors, electronic devices andpolymer composites. However, the poor dispersion of graphene and itsweak interfacial interaction with matrix still influence the reinforcementeffect on composites. To solve this problem, we devoted our work to thesurface functionalization of graphene sheets and preparation of modifiedgraphene based polymer composites. The details of the research are asfollows:(1) Polymethylmethacrylate (PMMA) functionalized graphene(GPMMA) was prepared via in situ polymerization with the liquid-phaseexfoliated graphene as precursor. By using GPMMA as fillers,GPMMA/PMMA composites were fabricated with solution-castingmethod. Various methods were used to confirm the successful grafting ofPMMA chains onto graphene sheets. Compared with pure PMMA,GPMMA/PMMA composites showed great enhancement in mechanicalproperties. For example, with addition of0.5wt%GPMMA, the Young’s modulus and tensile stress increased by151%and115%, respectively.The characterization of the fracture surface indicated that GPMMA waswell dispersed in the polymer matrix and had a strong interfacialinteraction. In addition, the thermal stability of GPMMA/PMMAcomposites was also remarkably improved.(2) Graphene oxide nanoribbon (GONR) was prepared by oxidativeunzipping of multiwalled carbon nanotube (MWNT), and then GONRwas surface functionalized with PMMA chains via in situ polymerization.The structure and morphology of PMMA functionalized GONR(GONR-P) were characterized by various methods. The mechanical testindicated that the Young’s modulus and tensile stress of PMMA-basedcomposites were greatly improved by the incorporation of GONR-P.Additionally, compared with GONR and PMMA functionalized MWNT,GONR-P was more effective on mechanical reinforcement. |
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