Synthesis of TiO2-polymer composite systems by atom transfer radicalpolymerization and their use in dye adsorption

TiO2 is a chemical substance that attracts attention due to its thermal stability, nontoxicity and extraordinary optical properties. In this study, TiO2 based nanomaterials were prepared. The prepared polymers were used in dye adsorption in aqueous solutions due to their environmentally friendly properties. TiO2 tends to agglomerate in polymer matrices. TiO2 surfaces need to be modified to reduce the tendency of TiO2 to agglomerate. Therefore, the best method to use is to graft polymer chains onto TiO2 surfaces via Surface Initiated Atom Transfer Radical Polymerization (SI-ATRP). In this thesis study, TiO2-polymer composite systems were prepared. Firstly, TiO2-Br macroinitiator was synthesized by modifying TiO2 surfaces. Polymer chains were grafted onto the TiO2 surface using the SI-ATRP method (TiO2-polymer). 2-(dimethylamino)ethyl methacrylate (DMA), N-isopropylacrylamide (NIPAM), tert-butyl methacrylate (tBuMA) and ethylene glycol dimethylacrylate (EGDMA) were used as monomers. PtBuMA blocks were converted to PMAA blocks by deprotection chemistry to obtain acidic blocks. Seven different composite systems were synthesized using these monomers. The prepared TiO2- polymer composite systems were used as adsorbents in the study of adsorption of methylene blue dye in aqueous solution. As a result of preliminary studies, adsorption studies were continued for TiO2-PMAA, TiO2-PDMA-b-PMAA and TiO2-PMAA-bPEGDMA composite systems, which reached the highest adsorption capacity (q) and adsorption percentage (%W) values. The effect of dye concentration and adsorbent amount change on adsorption was examined. Thermodynamic calculations were made by working with the TiO2-PMAA-b-PEGDMA composite system at three different temperature values (25 °C, 35 °C, 50 °C). It was observed that the adsorption between the TiO2-PMAA-bPEGDMA composite system and the dyes obeyed the Freundlich isotherm model and pseudo second order kinetics. At the same time, thermodynamic parameters such as ΔG, ΔH and ΔS were also calculated. Composite systems have been tried to be elucidated with TEM, SEM, FTIR and TGA analyses. UV-vis spectrophotometer was used in dye adsorption studies.