Thermoplastic Polyurethane-poly(N-isopropylacrylamide) Copolymer for Selective Uptake of Alcohol from Aqueous Solution

Abstract

Ethanol possesses high economic value, but as an industrial waste, it poses harm to human health and the environment. The paper describes the preparation of a thermoplastic polyurethane-poly (n-isopropylacrylamide) (TPU-PNIPAM) copolymer designed to selectively uptake alcohol in aqueous solution. The material was created by bonding TPU and PNIPAM together through intermolecular hydrogen bonds, enhancing its hydrophobic properties and making it easier to interact with alcohol molecules. As the amount of PNIPAM in TPU increases, the number of hydrophobic isopropyl groups in TPU-PNIPAM also increases, leading to an enhanced selective uptake ability of TPU-PNIPAM for alcohols in aqueous solution. When the temperature reaches 55 °C, the hydrophobic groups in TPU-PNIPAM are more exposed, further enhancing the selective uptake ability of TPU-PNIPAM for alcohols in aqueous solution. TPU-PNIPAM demonstrates selective preferential uptake for various concentrations and types of alcohol in aqueous solutions. The material’s selective uptake performance for alcohols increases with their hydrophobicity, so TPU-PNIPAM exhibited the best adsorption performance for a 10 wt% n-propanol solution under the combined effect of steric hindrance. In addition, TPU-PNIPAM exhibited selective adsorption for other organic solvents, which demonstrated the universality of TPU-PNIPAM in removing contaminants from aqueous solutions.