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

摘要

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 usingN ‐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,~(1)H‐NMR, particle size measurement, scanning electron microscopy, thermogravimetric analysis, UV–vis spectroscopy, and X‐ray diffraction analysis. PNIPAM, TRP, andb ‐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. The enhanced flocculation performance of thermoresponsive diblock copolymer (TRP) andb ‐CD grafted thermoresponsive diblock copolymerb ‐CD‐TRP is demonstrated below and above lower critical solution temperature (LCST) in kaolin suspension at neutral pH.