S. Zahir
Mar 1, 1979
Citations
0
Influential Citations
19
Citations
Journal
Journal of Applied Polymer Science
Abstract
In order to elucidate the reaction mechanism involved in the photocrosslinking of epoxide resins containing the 4,4′-dioxychalcone functional group as part of the polymer backbone, the behavior of the monomeric model compound, namely, the digylcidyl ether of 4,4′-dihydroxychalcone, when subjected to UV irradiation has been studied in some detail. The initial photochemical reaction is trans-cis isomerization to a photostationary state, the trans/cis ratios in this state being wavelength dependent. This is followed by a slow dimerization to dimers of the truxillic and truxinic type, the products being mainly formed from the trans isomer under our conditions of irradiation (λ = 350 nm). GPC studies on the irradiated products also reveal the formation of low molecular weight oligomers. Irradiation in the solid phase resulted in the conversion of 37% of the reacted monomer into polymer, whereas irradiation in the solution phase led to 23% of the reacted monomer being converted into low molecular weight polymer. A slow depolymerization of the dimer into the monomeric chalcone is also believed to occur on irradiation at 350 nm.