Synthesis of main chain polymeric benzophenone photoinitiator via thiol‐ene click chemistry and Its use in free radical polymerization

Abstract

Main chain polymeric benzophenone photoinitiator (PBP) was synthesized by using “Thiol‐ene Click Chemistry” and characterized with 1H NMR, FTIR, UV, and phosphorescence spectroscopies. PBP as a polymeric photoinitiator presented excellent absorption properties (ε294 = 28,300 mol−1L−1cm−1) compared to the molecular initiator BP (ε252 = 16,600 mol−1L−1cm−1). The triplet energy of PBP was obtained from the phosphorescence measurement in 2‐methyl tetrahydrofurane at 77 K as 298.3 kJ/mol and according to phosphorescence lifetime, the lowest triplet state of PBP has an n‐π* nature. Triplet–triplet absorption spectrum of PBP at 550 nm following laser excitation (355 nm) were recorded and triplet lifetime of PBP was found as 250 ns. The photoinitiation efficiency of PBP was determined for the polymerization of Hexanedioldiacrylate (HDDA) with PBP and BP in the presence of a coinitiator namely, N‐methyldiethanolamine (MDEA) by Photo‐DSC. The initiation efficiency of PBP for polymerization of HDDA is much higher than for the formulation consisting of BP. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Functional off-stoichiometry thiol-ene-epoxy thermosets featuring temporally controlled curing stages via an UV/UV dual cure process

“…14,15 Throughout the years, photopolymerization of thiol-enes has been shown both in industrial applications, including wearlayers in floor tiles, adhesives, coatings, electronics etc., and in academic applications for polymer synthesis, nanotechnology, biomaterials, lithography etc. [8][9][10][11][12][13][16][17][18][19][20][21] Thiol-ene photopolymerizations are typically described to proceed via a step-growth mechanism, 6,[22][23][24] and the reactions in thiol-ene photopolymerization can be generalized as seen in Scheme 1 below. 10 During the initiation step (1 and 2) a thiyl radical is formed as the SAH bond of a thiol group is cleaved.…”

Synthesis and photoinitiating activity study of polymeric photoinitiators bearing BP moiety based on hyperbranched poly(ester‐amine) via thiol‐ene click reaction

“…20 Moreover, there may undergo photolysis reaction at CAS bond as that in type I aside from Habstraction reaction, 21 which could greatly enhance the photoinitiating efficiency. [22][23][24] Yin et al [25][26][27] synthesized a series of macroinitiator bearing BP and sulfur. However, little work has been done for preparing hyperbranched polymeric BPs containing both amine and sulfur via thiol-ene click chemistry.…”

Photo-induced synthesis glucose-responsive carriers for controlled release of insulin in vitro

“…In the photochemical systems, photoinitiator plays a vital role in initiating the polymerization by generating active radicals under UV light irradiation through cleavage and hydrogen abstraction reactions [6]. Benzophenone and its derivatives are widely used as photoinitiator [7][8][9][10]. For example, Chung et al [11] reported that a series of urethane acrylate (UA) polymers had been prepared initiation by polyurethane (PU)-grafted benzophenone via photopolymerization method.…”