Abstract

1ʹ-(2-Acryloxyethyl)-3,3ʹ-dimethyl-6-nitrospiro[2 H-1-benzopyran-2,2ʹ-indoline] (SPA) was synthesized and grafted onto a water-soluble carboxymethyl chitin (CMCH) macromolecule to prepare a photochromic copolymer (CMCH-g-SPA). The structure of CMCH-g-SPA was characterized by Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis, X-ray diffraction (XRD) analysis, water-solubility evaluation, and UV-vis spectroscopy. XRD patterns of CMCH-g-SPA revealed that grafting copolymerization disrupts the CMCH semicrystalline structure, thus improving water solubility. UV-vis spectroscopy results supported the negative photochromic behavior of the merocyanine (MC) form of CMCH-g-SPA (CMCH-g-MCA) present in a water solution of the target copolymer. In addition to high solvent polarity, the intermolecular and intramolecular electrostatic attraction between the indolenine cation and the COO anion were found to be influencing factors, which stabilize these MC form of spiropyran groups grafted onto CMCH. In a water solution, visible light bleaching was completed over a short period (8 minutes) under artificial visible light irradiation and the thermal coloration reaction, whose rate constant at 25 °C was 4.64 × 10−4 s−1, which fit the first-order reaction equation. After ten photochromic cycles in water solution, the relative absorption intensity of CMCH-g-MCA decreased by 7.92%.

Details

Title
Preparation and analysis of photochromic behavior of carboxymethyl chitin derivatives containing spiropyran moieties
Author
Bin-Bin, Sun 1 ; Bing-Hua Yao 2 ; Zheng-Sheng, Fu 3 ; Yang-Qing, He 2 

 College of Materials Science and Engineering, Xi’an University of Technology, Xi’an, China; Department of Chemical Engineering, Shaanxi Vocational and Technical College of Defense Industry, Xi’an, China 
 College of Materials Science and Engineering, Xi’an University of Technology, Xi’an, China 
 College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, China 
Pages
106-117
Publication year
2020
Publication date
Dec 2020
Publisher
Taylor & Francis Ltd.
ISSN
1385772X
e-ISSN
15685551
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2469744618
Copyright
© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This work is licensed under the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.