Ultraviolet-photocurable oligomer. II. Syntheses and cured film properties of ultraviolet-photocurable BTDA-based caprolactone multiacrylate oligomers

Abstract

A series of ultraviolet (UV)-photocurable 3,3′4,4′-benzophenone tetracarboxylic dianhydride (BTDA)-based multiacrylate oligomers containing pendant glycidyl methacrylate (GMA) or glycidyl acrylate (GA) and caprolactone acrylate (Tone M-100) or caprolactone methacrylate (Tone M-201) were synthesized. The effects of the acrylic functional groups, the moles of GMA, and the molar ratio of Tone M-201 to Tone M-100 on their properties were investigated. The prepared photocurable oligomers were cured rapidly when exposed to UV or sunlight radiation without the addition of any extra photoinitiator or photosensitizer. The acrylate-type oligomer resulted in a lower thermal curing temperature and a fast curing rate. Increasing the moles of GMA or the molar ratio of Tone M-201/Tone M-100 on reaction led to a higher crosslinking density and resulted in film with higher Young's modulus, higher breaking strength, and lower elongation. The methacrylate type oligomer cured to a very hard but brittle film with higher Young's modulus and lower elongation. By contrast, the acrylate-type oligomer cured to a hard, tough film with lower Young's modulus and higher elongation. The film properties of the oligomers coated on steel plates were also investigated. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1625–1634, 1997