Evaluation of photo-induced crosslinking of thymine polymers using FT-IR spectroscopy and chemometric analysis

Abstract

Please cite this article as: Bortolato SA, Thomas KE, McDonough K, Gurney RW, Martino DM, Evaluation of photo-induced crosslinking of thymine polymers using FT-IR spectroscopy and chemometric analysis, Polymer (2012), doi: 10.1016/j.polymer.2012.09.007. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 2 ABSTRACTThe photo-induced immobilization of 4-vinylbenzyl thymine (VBT) and 4-vinylbenzyl triethyl ammonium chloride (VBA) copolymers has been investigated with the aid of grazing-angle specular-reflectance FT-IR spectroscopy. As irradiation time increases, changes in the structure of pendant thymine groups in the copolymer due to the crosslinking process result in shifts of the copolymer network's vibrational frequencies, as well as changes in numerous IR band intensities.In this work, chemometric methods have been applied to the FTIR data obtained while

Fluorescence spectroscopy and multivariate analysis as a greener monitoring tool: characterization of the curing kinetics of bioinspired polymers

“…Making use of these results and Equation (2) (Section 2), it is possible to identify the kinetics profiles of the species involved in the curing reaction ( Figure 5). Interestingly, the kinetics profiles are in agreement with reported results for VBT-VBA copolymers (16,18), suggesting that the curing process is only VBT-dependent. On the other hand, for each copolymer composition, the VPS species remains constant throughout the entire cross-linking reaction, while as the concentration of the VPS interferent augments, the chemometric resolution gets worse ( Figure 5(e)).…”

“…Regarding the spectral features of the excitation and emission profiles assigned to VBT (blue line in Figure 6(c)), reported data for thymine fluorescence (20) indicate a comparable emission maximum at 400 nm (λ exc = 295 nm), even if no quantitative evaluation of such similarity is possible. Finally, the refolded spectral profiles designed for the species generated in the curing reaction are in agreement with previously reported data (16,18), allowing us to make a suggestion of the species involved in the curing process (see Scheme 1).…”

“…In addition, our experience in using MCR-ALS algorithm afforded improved results compared to previous findings (11) for the curing reaction of VBT copolymers in solid phase using first-order FTIR spectroscopy (16). However, the obtained results were only qualitative, given that the analytical signals were non-selective.…”

“…Thymine has a fluorescence emission maximum at 410 nm when the excitation wavelength range is set between 290-340 nm (20); therefore it is likely that the observed signal corresponds to thymine groups in VBT copolymers. However, as irradiation time increases, thymine moieties get cross-linked to generate the cyclobutane ring (16,18). This effect cannot be easily observed on the EEFMs at different irradiation times, since only a mild reduction in the signal intensity can be seen, with no substantial changes of the spectra.…”

Curing kinetics, mechanism and chemorheological behavior of methanol etherified amino/novolac epoxy systems

“…Besides, it can be found that the characteristics peak at 1385 cm -1 assigned to -CH 3 stretching vibration in amino resin also decreased due to its reaction with epoxide group and hydroxyl group. Surprisingly, the peaks at 3447 cm -1 assigned to -OH stretching vibration increased over time in DEN/HMMM/EMI-24 system, which was due to the higher reaction activity of epoxide than that of hydroxyl, and the produced -OH was more than the consumed -OH, and these -OH increased the polar of cured polymer [34][35][36][37]. The relative high polarity of -OH resulted in high dielectric constant and water absorption, and the results were consistent with our previous works [15].…”