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Photopolymerization of an Epoxy Resin: Conversion and Temperature Dependence of its Refractive Index
Author(s) -
Aloui Faten,
Lecamp Laurence,
Lebaudy Philippe,
Burel Fabrice
Publication year - 2016
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201600093
Subject(s) - refractive index , photopolymer , epoxy , materials science , glass transition , temperature coefficient , composite material , optics , polymer chemistry , optoelectronics , polymer , polymerization , physics
Obtaining photocomposite materials with predefined optical properties requires a good knowledge of the refractive index evolution of the photopolymerizable media. In this aim, relationships between refractive index and conversion in the course of an epoxy resin photopolymerization are first established due to real time refractometric and infrared spectroscopic techniques. Refractive index value increases with conversion as long as the photocured material is not in glassy state. A shift of the relationship toward lowest refractive index values is observed when the reaction temperature increases. Second, the final photocured materials previously obtained are characterized. It is highlighted that the higher the photocuring temperature, the higher the epoxy conversion but the lower the material density at room temperature. This unusual result can be explained by the evolution of the material thermo‐optic coefficient, d n /d T . Indeed, the higher the conversion, the lower this coefficient.