Applicability of 1,6-Diphenylquinolin-2-one Derivatives as Fluorescent Sensors for Monitoring the Progress of Photopolymerisation Processes and as Photosensitisers for Bimolecular Photoinitiating Systems.

Monika Topa,Joanna Ortyl,Maciej Pilch,Kamil Machowski,Filip Petko,Mariusz Galek,Patryk Szymaszek

doi:10.3390/polym11111756

Abstract

The applicability of new 1,6-diphenylquinolin-2-oneas derivatives as fluorescent molecular sensors for monitoring the progress of photopolymerisation processes by Fluorescence Probe Technique (FPT) has been tested. The progress of cationic, free-radical and thiol-ene photopolymerisation for commercially available monomers: triethylene glycol divinyl ether (TEGDVE), trimethylolpropane triacrylate (TMPTA) and trimethylpropane tris(3-mercaptopropropionate) (MERCAPTO) was monitored. It was found that new derivatives of 1,6-diphenylquinolin-2-one shifted their fluorescence spectra towards shorter wavelengths with the progress of polymerisation, which enabled monitoring the progress in terms of fluorescence intensity ratios as the progress indicator. Derivatives of 1,6-diphenylquinolin-2-one show sensitivity to changes in both polarity and viscosity in the surrounding microenvironment during photopolymerisation processes. Therefore, it was shown that they are good candidates to act as fluorescent sensors for monitoring the kinetics of very quick processes, such as photopolymerisation processes. Furthermore, the effect of the nature of substituents attached to the 1,6-diphenylquinolin-2-one ring on the characteristics of emission spectra was identified. Moreover, the sensitivity of fluorescent sensors was compared with commercially available model sensors, such as 7-diethylamino-4-methylcoumarin (Coumarin 1) and trans-2-(2′,5′-dimethoxyphenyl)ethenyl-2,3,4,5,6-pentafluorobenzene (25ST). Moreover, it was also proven that selected derivatives of 1,6-diphenylquinolin-2-one exhibit an accelerating effect on the progress of cationic photopolymerisation of vinyl monomers (TEGDVE). Thus, the new 1,6-diphenylquinolin-2-one derivatives can be successfully used both as molecular fluorescence sensors to monitor the progress of photopolymerisation processes and as diaryliodonium salt photosensitisers to initiate cationic photopolymerisation processes in a UV-A range of 365 nm.

Highlights

Modern chemical technologies require increasingly quicker and more accurate methods for monitoring the course of processes in real time, both during production, including, among others, monitoring the degree of polymerisation, and at the stage of preparation for production or quality control of the finished products [1]
We propose obtaining new derivatives of 1,6-diphenylquinolin-2-one
All 1,6-diphenylquinolin-2-one derivatives demonstrated a sufficient fluorescence level (Table 1) for their spectral characteristics, which was measured at a probe concentration of ca. 0.1% by weight and a sample thickness of ca. 0.1 mm

Summary

Introduction

Modern chemical technologies require increasingly quicker and more accurate methods for monitoring the course of processes in real time, both during production (on-line), including, among others, monitoring the degree of polymerisation, and at the stage of preparation for production or quality control of the finished products (off-line) [1]. Quick photopolymerisation reactions are among the most in demand in on-line monitoring, due to the fact that the properties of the final product depend to a large extent on the conditions in which such photopolymerisation processes are carried out. It is, necessary to have a sufficiently quick and non-destructive measurement method applied, in order to monitor the progress of these processes in real time

Methods

Results

Conclusion