Synthesis, characterization and investigation of dielectric properties of copolymer / carbon nanotube composites

In this study, multiwall carbon nanotube (MWNT) polymer grafting was done by grafting to the surface. Copolymers containing 2% hydroxyethyl methacrylate (HEMA), styrene, methyl methacrylate and 1%, 5%, 10% HEMA in ethyl methacrylate were first synthesized by free radical polymerization reaction using AIBN initiator in order to accomplish this study. In the second step of the work, the -COOH group was introduced on the multi-wall carbon nanotubes by reacting with HNO3 / H2SO4 oxidizing acids. The carbon nanotube functionalized with MWNT-COOH was then converted to the acyl chloride derivative by reaction with thionyl chloride (SOCl2). Nanocomposites were prepared with poly (HEMA-co-St), poly (HEMA-co-MMA) and poly (HEMA-co-EMA) synthesized in different percentages with MWNT-COCl. The synthesized structures were characterized by FT-IR, 1 H-NMR. DSC and TGA curves of nanocomposites were taken and the thermal behaviors of the structures were investigated. SEM images were used to examine the morphology of the constructions. The electrical properties of the nanocomposites were examined in relation to frequency. Dielectric parameters such as dielectric loss factor, dielectric constants, conductivities and logarithm of conductivities were measured at different frequencies of the samples.