Synthesis of Porous Polymers by Nucleophilic Substitution Reaction of Polyamines and Monochlorotriazinyl-β-Cyclodextrin and Application to Dye Adsorption

TL;DR

Researchers created porous polymers using a chemical reaction between polyamines and a modified cyclodextrin, and found they can effectively adsorb dyes.

Contribution

A novel method for synthesizing porous polymers via nucleophilic substitution of polyamines and monochlorotriazinyl-β-cyclodextrin is introduced.

Findings

Porous polymers with varied morphologies were synthesized using different polyamines and reaction conditions.

The adsorption of dyes like methyl orange and methylene blue was achieved through ionic and π–π interactions.

Particle size and structure of polymers influenced mechanical properties like Young’s modulus and compressive strength.

Abstract

Network polymers with β-cyclodextrin moieties were prepared by nucleophilic substitution reactions between polyamines, linear polyethyleneimine (LPEI), polyallylamine (PAA), (ε-poly-L-lysine) (EPL), and monochlorotriazinyl-β-cyclodextrin (MCTCD) in methanol/water mixed solvent or water. The reactions under conditions of high material concentration (30 wt%) and a feed ratio of [MCT]/[NH] = 0.5 (mol/mol) successfully yield porous polymers via reaction-induced phase separation. The molecular structure of the polyamines and reaction conditions strongly affected the morphology of the resulting porous polymers. The porous polymers were composed of connected particles, gathered (slightly connected) particles, and/or disordered bulky structures, with sizes of 10−9 m–10−8 m. An increase in the molecular weight of LPEI and PAA and the feed molar ratio of [MCT]/[NH] tended to decrease the particle size. Young’s moduli of the LPEI-MCTCD and PAA-MCTCD porous polymers increased with an increase in bulk density, which was derived from small particle sizes. The wide particle size distribution and disordered structure caused collapse by the compression under 50 N of pressure. An LPEI-MCTCD adsorbed methyl orange, methylene blue, and phenolphthalein through ionic interactions, π–π interaction, and/or β-cyclodextrin inclusion.

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