Polyoxometalate cured epoxy resins with photochromic properties

• Published in: Colloid and polymer science Vol. 290; no. 16; pp. 1683 - 1693
• Main Authors: Zhong, Xinhui, Liu, Yi, Tang, Xiaolin, Wu, Qili, Li, Liang, Yu, Yingfeng
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.11.2012; Springer; Springer Nature B.V
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Exact sciences and technology; Food Science; Nanotechnology and Microengineering; Original Contribution; Physical Chemistry; Physicochemistry of polymers; Polymer Sciences; Polymerization; Polymers and radiations; Soft and Granular Matter; Epoxy resin; Polyoxometalate; Cationic polymerization; Photochromism; Ring opening polymerization; Tungsten compound; Bulk polymerization; Priming activity; Experimental study; Photoinitiator; Heteropolyacid; Photopolymerization; Optical properties; Crosslinked polymer; Phosphorus compound; Kinetics; Cationic catalyst; Glycidyl ether polymer; Activation energy; Photobleaching
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-012-2688-9

Novel photochromic thermosetting materials were facilely prepared by polyoxometalate, Keggin-type H 3 PW 12 O 40 , cured epoxy networks with ethylene oxide blocks. The dual functions of polyoxometalate as both hardener and photochromophore were studied by differential scanning calorimetry, infrared spectroscopy, ultraviolet–visible spectroscopy (UV–vis), and generalized two-dimensional correlation analysis. Polyoxometalate initiates the cationic polymerization of epoxy resin through dissolving in either polyethylene oxide epoxy or organic solvents. When subjected to UV irradiation, the transparent thermosetting materials with ethylene oxide blocks change from colorless to blue, and could be bleached in air at various temperatures to recover its initial state. From the UV–vis measurements, all the resultant thermosetting materials demonstrated similar photochromic behavior after ultraviolet irradiation showing characteristic d–d transition band and intervalence charge transfer band. The 2D correlation analysis of the photochromic spectra clearly revealed the sequence of electron movements in the framework of PW 12 anion.