Evidences for π-interactions between pyridine modified copolymer and carbon nanotubes and its role as a compatibilizer in poly(methyl methacrylate) composites

Poly(methyl methacrylate-co-methacrylic acid) was modified with 4-aminomethyl pyridine, in order to facilitate π–π interactions with carbon nanotubes. The π–π* transitions of both the carbon nanotubes and the pyridine modified copolymer were observed by X-ray photoelectron and UV–vis spectroscopy, respectively. The π-interactions themselves were evident by UV–vis absorbance quenching and red shift and also by fluorescence emission quenching and blue-shift. Those spectroscopic evidences suggested that the nanotubes were wrapped by the modified copolymer through π–π interactions. Introducing the pyridine modified copolymer as a compatibilizer in polymethyl methacrylate composites enabled improved nanotube dispersion, which led to reductions in volume resistivity and increases in composite storage modulus. Those results indicated that this novel compatibilizer could be suitable for a variety of carbon nanotube/poly(methyl methacrylate) composite based applications, where improved nanotube dispersion is desirable without damaging the nanotubes inherent properties.