Novel Chemical Architectures Based on Beta-Cyclodextrin Derivatives Covalently Attached on Polymer Spheres

Abstract

This study presents the synthesis and characterization of polymer derivatives of beta-cyclodextrin (BCD), obtained by chemical grafting onto spherical polymer particles (200 nm) presenting oxirane functional groups at their surface. The polymer spheres were synthesized by emulsion polymerization of styrene (ST) and hydroxyethyl methacrylate (HEMA), followed by the grafting on the surface of glycidyl methacrylate (GMA) by seeded emulsion polymerization. The BCD-polymer derivatives were obtained using two BCD derivatives with hydroxylic (BCD-OH) and amino groups (BCD-NH2). The degree of polymer covalent functionalization using the BCD-OH and BCD-NH2 derivatives were determined to be 4.27 and 19.19 weight %, respectively. The adsorption properties of the materials were evaluated using bisphenol A as a target molecule. The best fit for the adsorption kinetics was Lagergren’s model (both for Qe value and for R2) together with Weber’s intraparticle diffusion model in the case of ST-HEMA-GMA-BCD-NH2. The isothermal adsorption evaluation indicated that both systems follow a Langmuir type behavior and afforded a Qmax value of 148.37 mg g−1 and 37.09 mg g−1 for ST-HEMA-GMA-BCD-NH2 and ST-HEMA-GMA-BCD-OH, respectively. The BCD-modified polymers display a degradation temperature of over 400 °C which can be attributed to the existence of hydrogen bonds and BCD thermal degradation pathway in the presence of the polymers.

Bisphenol A Adsorption on Silica Particles Modified with Beta-Cyclodextrins

“…The weight loss up to 120 °C was attributed to the physisorbed water desorption from the surface and pores [ 51 ], while at temperatures of over 200 °C the weight loss was due to de-hydroxylation of silica surface [ 52 ]. At temperatures of 280–320 °C, the decomposition of BCD took place [ 39 ]. It was noticed that the weight loss for SiO 2 -BCD-OH was around 29.7%, while for SiO 2 -BCD-NH 2 the value was 25.8%.…”

“…The synthesis procedure and characterization of BCD-NH 2 were presented in our previous study [ 39 ]. Briefly, the procedure for obtaining BCD-NH 2 was as follows: 5.5 g mono tosylated-BCD (4.266 mmol) were dissolved in 166 mL of 1,4-diaminobutane (DAB), slowly warmed up to 70 °C, and kept at this temperature for 24 h. At the end of the reaction time, the solvent was vacuum distilled and the solid that resulted was dissolved in a minimum amount of water.…”

“…The final product was obtained by drying the sample in a vacuum oven at 40 °C for 2 days with a 54% yield. NMR and MALDI characterization were presented in our previous study [ 39 ].…”

“…The drawbacks of these methods are strongly related sometimes with the rigorous control of parameters in the case of biological or advanced oxidation procedures and laborious or expensive synthesis methods for membranes [ 35 , 36 ]. These circumstances have driven the attention of researchers to the design of CDs-based inclusion complexes that could be used to adsorb the BPA molecules from the polluted environment [ 37 , 38 , 39 , 40 ].…”