Dibenzophenazine and quinoxaline derivatives as novel visible photosensitizers for diaryliodonium salts

Kolay, Merve
This study is focused on the use of visible light in photoinitiated cationic polymerization. Photoinitiated polymerization of oxiranes, vinyl ethers, and other vinyl monomers was achieved. In doing so, (2-(2,3 dihydrobenzo [b][1,4]dioxin-6-yl)-3-(2,3-dihydrobenzo[b]-[1,4]dioxin-7-yl)-5-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-8-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7yl) quinoxaline) (DBQEd) and poly(2,3,5,8-tetra(thiophen-2-yl)quinoxaline) (TTQ), two dibenzo[a,c]phenazine derivatives; 10,13-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)dibenzo[a,c] phenazine (PHED) and 10,13-bis(4-hexylthiophen-2-yl)dibenzo[a,c]phenazine (PHEHT) were utilized as the photosensitizers for diaryliodonium salt photoinitiators. Novel dyes based on the dibenzo[a,c]phenazine and quinoxaline skeleton were shown to be efficient in carrying out the cationic photopolymerizations of a wide variety of epoxide, oxetane, and vinyl monomers at room temperature upon irradiation with long-wavelength UV and visible light. The polymerizations were initiated at room temperature in the presence of diphenyliodonium hexafluorophosphate (Ph2I+PF-6) and monitored by optical pyrometry (OP). The photopolymerization of an epoxide monomer via solar irradiation was also demonstrated.


Numerical and experimental investigation on laser damage threshold of highly reflective multilayer thin films
Ocak, Mustafa; Sert, Cüneyt; Okutucu Özyurt, Hanife Tuba; Department of Mechanical Engineering (2016)
The laser induced temperature distributions on the optical thin films are investigated in this study. Effects of optical design modifications on thermal performance of highly reflective (HR) multilayer thin films are analyzed. Firstly, a conventional 19 layer HR coating is selected as a reference and the laser induced temperature distribution is evaluated on it. Then, alternative HR designs are developed by employing non-quarter wave layers, over coat (OC) layers and two high index materials in the coating ...
Digestion of animal- and plant-based proteins encapsulated in kappa-carrageenan/protein beads under simulated gastrointestinal conditions
Özel, Barış; He, Lili; McClements, David Julian (Elsevier BV, 2020-11-01)
In this study, we encapsulated both animal-derived (whey) and plant-derived (soy and pea) proteins within polysaccharide/protein beads and measured the digestion of these beads under simulated gastrointestinal tract (GIT) conditions. Bead dimensions were measured using a digital caliper and found to increase as the shear thinning behavior of the protein/polysaccharide solutions used to form them increased. The hydrolysis of the plant and animal proteins trapped inside the protein/polysaccharide beads was st...
Rheological characterization of tahin/pekmez (sesame paste/concentrated grape juice) blends
Arslan, Elif; Esin, Ali; Yener, Esra; Department of Food Engineering (2003)
The aim of this study was to determine the rheological properties of tahin/pekmez blends at different tahin concentrations (20-32%) and temperatures (35-65 C) by using a concentric cylinder rotational viscometer. Samples were sheared with seven different rotational speeds at an increasing order. The shear rates (0.75-63.9 s-1) were calculated by the Power-law Approximation method. Tahin/pekmez blends were found to exhibit non-Newtonian, shear thinning behavior at all temperatures and tahin concentrations. T...
Microwave initiated polymerization of trihalophenyleneoxide and aniline
Levent, Fulya; Kısakürek, Duygu; Toppare, Levent Kamil; Department of Polymer Science and Technology (2011)
The aim of the study is to synthesize poly(dibromophenyleneoxide) and polyaniline separately applying different microwave energies (90-900 watt), water amounts (1-5 ml) and time intervals (2-10 min) and investigate the effects of these parameters on the percent conversion of the polymers. The synthesis of poly(dibromophenyleneoxide) (P), radical ion polymer (RIP) and crosslinked polymer (CLP) were achieved by using tribromophenol (TBP) and Ca(OH)2 via microwave energy in a very short time interval. P and RI...
Multichromic benzimidazole-containing polymers: Comparison of donor and acceptor unit effects
Nurioglu, Ayda Goycek; Akpinar, Hava; Sendur, Merve; Toppare, Levent Kamil (2012-09-01)
This study reports a comparative study on electrochromic properties of two donoracceptordonor (DAD)-type polymers namely poly(2-heptyl-4,7-di(thiophen-2-yl)-1H-benzo [d]imidazole) (BImTh) and poly(4,7-bis(2,3-dihydrothieno[3,4-b] [1,4]dioxin-5-yl)-2-heptyl-1H-benzo[d]imidazole) (BImEd). DAD-type monomers were polymerized electrochemically on indium tin oxide-coated glass slides to determine the optical properties of the polymers. Electrochemical rho-doping experiments were performed to determine the band ga...
Citation Formats
M. Kolay, “Dibenzophenazine and quinoxaline derivatives as novel visible photosensitizers for diaryliodonium salts,” M.S. - Master of Science, Middle East Technical University, 2011.