Production of polymer based functional nanocomposite materials

Since nanocomposites are materials with a high surface-to-volume ratio, they show better mechanical, thermal, optical, chemical and physical properties compared to the pure form of the material. Nanofibers, which have become one of the new generation nanocomposite materials, have higher surface area/volume ratio, low density, low specific gravity, high porosity, small pore size, high biocompatibility, strength, smooth structure and coating properties thanks to their small size. Electrospinning technique is the most frequently used method in nanofiber production recently and the fibers produced by this method can be a hundred times smaller radius than the fibers produced by the classical method. Click chemistry is known as a set of reactions that are highly efficient, compatible with many functional groups, perform with high selectivity, allow functional group diversity, have short reaction times, are not sensitive to the solvents used, can be separated without using chromatographic methods, are harmless, and forms by-products in negligible low concentrations. In this study, in-situ preparation and functionalization of poly(vinyl chloride) (PVC) nanofiber was investigated by combination of copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) click chemistry and electrospinning methods. The succesful production of functional PVC nanofibers has been confirmed by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic spectroscopy (1H-NMR) methods. The efficiency of CuAAC click reactions was monitored by FT-IR spectroscopy through the decrease on the azide band of PVC. The best CuAAC click efficiency was found as 70% with optimized condition (6:2:0,01= azide-functional PVC: phenylacetylene: copper(II) sulfate pentahydrate, 35 kV voltage, negatively charged collector and 0,1 mm/h feeding speed). In addition, 1H-NMR spectroscopy confirmed the chemical structure of clicked product of PVC-N3 and phenylacetylene and the CuAAC click efficiency was calculated as 69,2%. The in-situ functionalization of PVC-N3 led to obtain improved thermal properties of the clicked product (86.1 oC) based on differential scanning calorimeter (DSC). The obtained fibers are in nanoscale that proved by scanning electron microscopy (SEM). The diameters of nanofibers were investigated by SEM and nanofiber diameters were found between 20-400 nm. Keywords: Click chemistry, Electrospinning, Nanofibers