Real-Time Infrared Determination of Photoinitiated Copolymerization Reactivity Ratios:  Application of the Hilbert Transform and Critical Evaluation of Data Analysis Techniques

• Published in: Macromolecules Vol. 37; no. 6; pp. 2275 - 2286
• Main Authors: Jansen, Johan F. G. A, Houben, Erwin E. J. E, Tummers, Peter H. G, Wienke, Dietrich, Hoffmann, John
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 23-03-2004
• Subjects: Applied sciences; Exact sciences and technology; Physicochemistry of polymers; Polymerization; Polymers and radiations; Vinyl derivative copolymer; Data analysis; Fourier transformation; Maleate copolymer; Hydroxyethyl methacrylate copolymer; Multivariate analysis; Experimental study; Real time; Reactivity ratio; Hilbert transformation; Two dimension spectrometry; Infrared spectrometry; Vinyl ether copolymer; Fumarate copolymer; Allylic derivative copolymer; Measurement method; Hydroxyethyl acrylate copolymer; Photochemical copolymerization
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma035587r

The reactivity ratios of various UV-copolymerizing systems were determined employing RT-FTIR spectroscopy, combined with advanced and alternative multivariate-statistical data analysis techniques. For complex mixtures peak identification as well as peak deconvolution has been increased significantly by employment of 2-dimensional correlation spectroscopy, based on the Hilbert transform. As an advantage, kinetic reaction profiles of homo- and copolymerization reactions have been extracted and have been separated without any additional measurement. The following reactivity ratios were obtained:  fumarate/vinyl ether r 1 = 0, r 2 = 0; maleate/vinyl ether r 1 = 0, r 2 = 0; fumarate/allyl ether r 1 = 0, r 2 = 0; maleate/allyl ether r 1 = 0, r 2 = 0; fumarate/methacrylate r 1 = 0, r 2 = 1.3; fumarate/acrylate r 1 = 0, r 2 > 50; methacrylate/vinyl ether r 1 = 16, r 2 = 0; methacrylate/allyl ether r 1 > 100, r 2 = 0; methacrylate/acrylate r 1 = 1.6, r 2 = 0.15; methacrylate/N-vinylcaprolactam r 1 = 7.3, r 2 = 0.01; and acrylate/N-vinylcaprolactam r 1 = 1.3, r 2 = 0.01. Kinetically, the fumarate−vinyl ether copolymerization can be regarded as the homopolymerization of a CT complex while the fumarate allyl ether copolymerization should be regarded as a perfect alternating copolymerization. The HEA−NVC copolymerization has to be regarded as a terpolymerization between HEA, NVC, and the HEA−NVC charge-transfer complex.