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Branched Base‐Amplifying Oligomers Enhancing UV‐Curing of Epoxy Resins
Author(s) -
Aoki Ken'ichi,
Ichimura Kunihiro
Publication year - 2009
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.200900178
Subject(s) - epoxy , glycidyl methacrylate , curing (chemistry) , polymer chemistry , oligomer , photosensitivity , amine gas treating , chemistry , phototoxicity , uv curing , methacrylate , acrylate , materials science , polymer , organic chemistry , copolymer , biochemistry , optoelectronics , in vitro
This paper describes the preparation and the enhancing effect on anionic UV‐curing of epoxy resins of three and four‐armed oligomers bearing 9‐fluorenylmethyl carbamate residues, which displayed the autocatalytic formation of primary amino residues triggered by a photogenerated amine. The branched oligomers were readily synthesized by the Michael addition of the corresponding polythiol with 9‐fluorenylmethyl 2‐acryloyloxyethylcarbamate, which were obtained from 9‐fluorenylmethanol and commercially available 2‐isocyanatoethyl acrylate. Films of poly(glycidyl methacrylate) and a glycidylated novolac resin doped with a photobase generator exhibited boosted photosensitivity leading to photoinsolubilization in the presence of the base‐amplifying oligomers. The more marked effect of the branched oligomers on UV‐curing of epoxy resins was demonstrated by using films of a fluid epoxy, which were converted into hard films after UV exposure and post‐exposure baking, whereas no hardening occurred in the absence of the oligomers.