One-pot synthesis of novel chitosan-salicylaldehyde polymer composites for ammonia sensing

Abstract

Chitosan (Chs)-salicylaldehyde (Sal) polymer derivatives were formed via the reaction of Chs-Sal with zinc oxide nanoparticles (ZnO NPs) and beta-cyclodextrin (β-CD). These polymers were synthesized through inclusion with β-CD and doping with ZnO NPs to give pseudopolyrotaxane and Chs-Sal/ZnO NPs composite, respectively, for low-temperature detection and sensing of NH3 vapors as great significance in environmental control and human health. Additionally, the polymer (Chs-Sal/β-CD/ZnO NPs) was prepared via the insertion of generated composite (Chs-Sal/ZnO NPs) through β-cyclodextrin ring. The structural and morphological characterizations of the synthesized derivatives were confirmed by utilizing FTIR, XRD and, SEM, respectively. Also, the optical properties and thermal gravimetric analysis (TGA) of the synthesized polymers were explored. The obtained results confirmed that using β-CD or ZnO NPs for modification of polymer (Chs-Sal) dramatically enhanced thermal stability and optical features of the synthesized polymers. Investigations on the NH3-sensing properties of Chs-Sal/β-CD/ZnO NPs composite were carried out at concentrations down to 10 ppm and good response and recovery times (650 s and 350 s, respectively) at room temperature (RT) and indicated that modification by β-CD and doping with ZnO NPs effectively improves the NH3-sensing response of Chs-Sal from 712 to 6192 using Chs-Sal/β-CD/ZnO NPs, respectively, with low LOD and LOQ of 0.12 and 0.4 ppb, respectively.

Nanocellulose@gallic Acid-Based MOFs: A Novel Material for Ecofriendly Food Packaging

“…More shifting was observed in the CH-5% NC-1.5% MOF and CH-10% NC-2.5% MOF films from 19.0 to 22.61° and to 23.56°, respectively (Figure ). The broadness in the peak indicated a reduction in the crystallinity of the compound by the hydrogen-bonding interaction between the components . The shifts in the diffraction peaks were ascribed to the presence of NC and the MOF, with their respective peaks occurring at 22.80 and 22.39°, indicating significant intercomponent interactions .…”

“…The broadness in the peak indicated a reduction in the crystallinity of the compound by the hydrogen-bonding interaction between the components. 47 The shifts in the diffraction peaks were ascribed to the presence of NC and the MOF, with their respective peaks occurring at 22.80 and 22.39°, indicating significant intercomponent interactions. 45 Interestingly, the characteristic peaks of NC and the MOF were absent in the powder-XRD spectra of the composite films, likely due to their lower concentrations relative to CH.…”