Characterization of cross-linking structures in UV-cured acrylic ester resin by MALDI-MS combined with supercritical methanolysis.
The cross-linking structure of the ultra violet (UV)-cured resin prepared from dipentaerithritol hexacrylate (DPHA) was characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with supercritical methanolysis. The MALDI-mass spectrum of the decomposition products obtained by supercritical methanolysis contained a series of peaks of sodium-cationized methyl acrylate (MA) oligomers up to around m/z = 4000 formed through selective cleavage and methylation occurred at ester linkages in UV-cured DPHA. Furthermore, in order to observe widely distributed sequence lengths in the cross-linking junctions, the decomposed products of the cured resin were then fractionated using size exclusion chromatography followed by the MALDI-MS measurements of the individual fractions. The MALDI-mass spectra of the lower molar mass fractions mainly consisted of a series of peaks of MA oligomers around m/z values of several thousands, whereas those of higher molecular weight showed a broad peak up to m/z ca. 180000. The observed distributions of the supercritical methanolysis products suggested that the network junctions in the given UV-cured resin were composed of up to around 2000 acrylate units.
Matsubara
Hideki
H
Aichi Industrial Technology Institute, Kariya.
Hata
Shun-Ichiro
S
Kondo
Yosuke
Y
Ishida
Yasuyuki
Y
Takigawa
Hiroshi
H
Ohtani
Hajime
H
D000179:Acrylates / Q000737:chemistry; D000180:Acrylic Resins / Q000737:chemistry* / Q000528:radiation effects*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D014466:Ultraviolet Rays
D000179:Acrylates; D000180:Acrylic Resins; D003432:Cross-Linking Reagents; C035956:methyl acrylate