Photo-initiated and thermal curing of epoxides by the use of photo-base generators bearing acyloxyimino groups

Abstract

The formation of amines by the photolysis of 0-acyloximes derived from acetophenone oxime, benzophenone oxime, fluorenone oxime, and 2-acetonaphthone oxime and the curing of epoxides by the resulting amines were investigated. The quantum yields of their photolysis at 366 nm in polystyrene films depend on their structures, and those for bifunctional ones bearing phenyl or naphthyl moieties were found to be very high, at 0.88 and 0.76, respectively. The yields of the resulting amines in polymer matrices were higher than those in solution. The yields for 0-acyloximes bearing a naphthyl moiety were ca. 90% and higher than for those bearing a phenyl moiety. Although the resulting amines.were efficient photo-cross-linkers for poly(g1ycidyl methacrylate), they were not effective for curing of epoxy resins (oligomers). On the other hand, polymer amines with a glass transition temperature lower than room temperature, which were obtained by the photolysis of copolymers bearing acyloxyimino groups, were found to be effective photo-cross-linkers for the epoxy resins.Key words: photo-base generator, acyloxyimino group, photo-initiated and thermal curing, poly(glycidy1 methacrylate), epoxy resin.RCsumC : On a CtudiC la formation d'amines par la photolyse d'O-acyloximes dtrivtes des oximes de l'acCtophCnone, de la benzophtnone, de la fluorhone et de I'actto-2-naphtone et la rCaction des amines qui en rCsultent avec les Cpoxydes. Les rendements quantiques de leurs photolyses h 366 nm, dans des films de polystyrkne, dependent de leurs structures; on a trouvC que ceux des composCs bifonctionnels avec des portions phCnyle ou naphtyle sont trks ClevCs, soit respectivement 0,88 et 0,76. Les rendements des amines qui en rCsultent dans les matrices de polymkre sont plus elevCs que ceux en solution. Les rendements pour les 0-acyloximes portant un groupe naphtyle sont plus Clevts (environ 90%) que ceux des acyloximes portant un groupe phCnyle. MCme si les amines qui en rCsultent sont des photorCticuleurs efficaces pour le poly(rnCthacry1ate de glycidyle), ils ne sont pas efficaces pour la cuisson des rCsines Cpoxy (oligomkres). Par ailleurs, on a trouvC que les amines polymCriques, qui se forment par photolyse de copolymkres portant des groupes acyloxyimino et qui prCsentent une temperature de transition vitreuse infkrieure i la temptrature ambiante, sont des photorCticuleurs efficaces pour les rCsines Cpoxy.Mots clks : gCnCrateur de photobase, groupe acyloxyimino, photoinitiation et cuisson thermique, poly(mCthacry1ate de glycidyle), rtsine Cpoxy. [Traduit par la rCdaction]A large number of photo-acid generators such as aromatic diazonium salts and aromatic iodonium salts have been developed and their wide use in the fields of photo-curable coatings (1)

Study on Photobase Generation from .ALPHA.-Aminoketones: Photocrosslinking of Epoxides with Carboxylic Acids.

“…These subsets are labeled as (1)-(6) in the histogram in Figure 10. The folded conformations appear in the energy ranges (1) and (4) in which the total number of conformations is 20. The stretched conformations are observed in the ranges (2), (3), (5) and (6) with the total number of 44 conformations.…”

“…For example, photogenerated bases have been used in the development of photoimageable polyimides [ 1 ], in a chemically amplified photolithography based on catalyzed decarboxylation [2], and in crosslinking of polymers bearing pendant epoxy groups [3]. Some compounds have already been known as photobase generators, for example cobalt complexes [3], 0-acyloximes [4] and o-nitrobenzyloxy carbonyl derivatives [1,2,5], which generate amines.…”

Synthesis of Photobase Generators Based on Proazaphosphatrane ? Tetraarylborate Complex for i-Line Photopatterning

“…A photobase generator (PBG) is a promising photoactive compound in industry [2], but the studies of PBGs are scarce. So far, several types of PBGs were reported such as the cobalt-amine complex [3], o-nitrobenzoyl carbamates and urethanes [4], o-acyloximes [5], blocked aniline [6], and benzoin carbamate [7] Recently bicyclic guanidium tetraphenylborate complexes as a super-photobase generator (pK a ~ 26) were synthesized and applied to the formation of photopolymer system for 250 nm photopatterning [8]. Here we report novel PBGs based on proazaphosphatrane (pK a > 33) and tetraaryl borate complex for i-line photopatterning system.…”

I-Line Sensitive Photoacid and Photobase Generators and Their Use for Photocrosslinking System Based on Poly(vinylphenol) and Diepoxy Fluorene Derivatives.

“…In that system, triphenylsulfonium triflate (TPST) was used as a photoacid generator, and 0-phenylacetyl acetonaphtone oxime (PaAnO) [5] as a photobase generator.…”

“…9-Fluorenylideneimino p-toluenesulfonate (FITS) [3] and PaAnO [5] were prepared as reported previously. Other reagents were purchased and used without further purification.…”