Dispersion of carbon nanotubes via ionic hyperbranched copolymers in water using π-π stacking interactions and investigation of their properties

In recent years, hyperbranched polymers have been attractive because of their various physical and chemical properties. Hyperbranched polymers have many superior properties due to architectural structures which can contain many different functional groups. These materials have begun to use both in academic studies and industrial areas owing to features such as high solubility and low viscosity. In this study, synthesized tertiary amine functional hyperbranched copolymers possessing pyrene functional groups attached onto carbon nanotubes surface. Afterwards, it is aimed to disperse of carbon nanotube via ionic hyperbranched copolymers in water and characterize with several techniques. For this purpose, in the first step photopolymerization reaction was carried out with methyl methacrylate (MMA) and amine based monomer 2-(Diethylamino) ethyl methacrylate (DEAEMA) in the presence of a Type II photoinitiator (BP) and hyperbranched copolymeric structures were obtained. Because these monomers named 2-(Diethylamino) ethyl methacrylate which have tertiary amine groups in their structures are strong hydrogen donors, branched points can be formed on the polymer backbone during the photopolymerization reaction. Secondly hyperbranched polymers were possessed functionality via modification with 1-(Bromoacetyl) pyrene. Finally, it was provided to attach functional hyperbranched polymers onto carbon nanotubes surface with the physical interactions. After the studies, it was observed that polymer- modified carbon nanotubes had much better dispersions in organic solvents. The copolymers and carbon nanotubes which have hydrophobic properties were hydrophilically modified by quaternization with HCl and resulting carbon nanotubes were dispersible in aqueous media. In these studies, hyperbranched copolymers were synthesized using various monomer concentrations. DEAEMA was prepared as four different feed ratios which have been 5%, 20%, 50% and 100% moles respectively. After polymerizations, conversion percentages were calculated by gravimetrically. Besides, hyperbranched polymers were investigated by Gel- Permeation Chromatography (GPC), Proton Nuclear Magnetic Resonance (1H NMR), UV-Visible Spectrophotometer and Thermal Gravimetric Analysis (TGA).