Synthesis, Characterization, and Flocculation Studies of β-Cyclodextrin-Based Stimuli-Responsive Star Copolymer: An Environmental Remediation

Abstract

Thermoresponsive star polymers are synthesized by using poly(NIPAM-b-DMA) diblock copolymer and β-cyclodextrin (β-CD). The synthesis of thermoresponsive diblock copolymer (TRP) is carried out by reversible addition–fragmentation chain transfer mediated aqueous polymerization using N-isopropylacrylamide (PNIPAM) and di-methylacrylamide as monomers. Mercaptopropionic acid is used as in situ chain transfer agent (CTA) to synthesize PNIPAM, i.e., macro-CTA. The polymeric materials are characterized by Fourier-transform infrared spectroscopy, gel permeation chromatography, 1H-NMR, particle size measurement, scanning electron microscopy, thermogravimetric analysis, UV–vis spectroscopy, and X-ray diffraction analysis. PNIPAM, TRP, and b-CD grafted thermoresponsive diblock copolymer (β-CD-TRP) show lower critical solution temperature at 32.8, 34.3, and 36.8 °C, respectively. TRP and β-CD-TRP are also studied for the removal of model contaminant (kaolin). Among all grades, β-CD-TRP 4 shows the best performance in the removal of kaolin from aqueous solution at 25 and 50 °C.