Producing critical exponents from gelation for various photoinitiator concentrations; a photo differential scanning calorimetric study
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Date
2012
Authors
Dogruyol, Zekeriya
Arsu, Nergis
Dogruyol, Sevnur Keskin
Pekcan, Önder
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier Science SA
Open Access Color
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Abstract
Photoinitiated radical polymerization of an 80 wt% epoxy diacrylate (EA) and 20 wt% tripropyleneglycoldiacrylate (TPGDA) mixture with various 2-Mercaptothioxanthone (TX-SH) photoinitiator concentrations was studied by using photo-differential scanning calorimetric (Photo-DSC) technique. Photopolymerization reactions were carried out under the same conditions of temperature and light intensity. It was observed that all conversion curves during gelation at various photoinitiator concentration present nice sigmoidal behavior which suggests application of the percolation model. The critical time where polymerization reaches the maximum rate (Rp(max)) is called the glass transition point (t(g)). The gel fraction exponents beta were produced from the conversion curves around t(g). The observed critical exponents were found to be around 0.55 predicting that the gel system obeys the percolation model. Rp(max) and final conversion (C-5) values were found to be increased as the photoinitiator concentration was increased. On the other hand t(g) values decreased as photoinitiator concentration was increased indicating higher TX-SH concentration causes early glass transition during radical polymerization. (C) 2011 Elsevier B.V. All rights reserved.
Description
Keywords
Critical exponent, Epoxy acrylate, Photo-DSC, Photoinitiator concentration
Turkish CoHE Thesis Center URL
Fields of Science
Citation
14
WoS Q
Q1
Scopus Q
Q1
Source
Volume
74
Issue
1
Start Page
181
End Page
185