Photodegradation of O‐methacryloyl ketone oxime‐methyl mechacrylate copolymers in the solid phase

Tsunooka, Masahiro; Imono, Syozo; Nakayama, Keisuke; Kuwabara, Hidemasa; Tanaka, Makoto

doi:10.1002/pola.1986.080240210

Cited by 18 publications

(6 citation statements)

References 11 publications

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“…Therefore, the degradabilities of the polymer films parallel those of the polymer solutions. We also found that increasing the irradiation temperature (up to 100°C) facilitated the main‐chain scission and retarded the crosslinking,17 which may be due to the increased chain mobility 15…”

Section: Resultsmentioning

confidence: 65%

“…The oxidation of tertiary alkyl radicals in the main chain would hinder the β‐scission predominantly occurring in PBMA. The alkyl radicals formed in PBA, through side‐chain degradation and hydrogen abstraction or other processes, would react with oxygen to produce hydroperoxide and finally carbonyl groups, which could initiate the photooxidative scission of the main chain 8, 10, 12, 15. It is noteworthy that oxygen facilitates the main‐chain scission of the PBMA film as well as the PBA one and diminishes their crosslinking.…”

Section: Resultsmentioning

confidence: 99%

“…In the latter cases, the degradation occurs randomly over the whole polymer chains. On the other hand, polymethacrylates containing aromatic groups in the side chains are susceptible to side‐chain photodegradation,13, 14 which induces main‐chain scission in some cases 15…”

Section: Introductionmentioning

confidence: 99%

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Photolysis of poly(benzyl methacrylate)s and poly(benzyl acrylate)s in solution and films

Itoh

Goshima

Shirai

2001

J of Applied Polymer Sci

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Methacrylate and acrylate copolymers containing benzyl or 1-phenylethyl groups and their monomeric model compounds were irradiated with a 254-nm light in CH 2 Cl 2 and solid films. Low molecular weight and polymeric products were analyzed by gas chromatography (GC) and NMR spectroscopy, respectively, and main-chain scission efficiencies were determined by gel permeation chromatography (GPC). The results indicate that the ester bond cleavage in the side chain produces alkyl radicals in the main chain, leading to main-chain scission and crosslinking. The higher stability of tertiary alkyl radicals formed in methacrylate polymers lead to the predominant main-chain scission in solution. On the other hand, acrylate polymers were less susceptible to photodegradation. The degradabilities of the polymer films reflected those of the polymer solutions, although crosslinking preferentially occurred. The distinct effect of oxygen on the degradation was also observed in solution and films.

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Section: Resultsmentioning

confidence: 65%

Section: Resultsmentioning

confidence: 99%

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Photolysis of poly(benzyl methacrylate)s and poly(benzyl acrylate)s in solution and films

Itoh

Goshima

Shirai

2001

J of Applied Polymer Sci

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“…Their structures and characteristics are shown in Fig. 1 and Table 1, respectively. 0-Acryloyl acetophenone oxime (AAPO) and 0-acryloyl 2-acetonaphthone oxime (AANO) were prepared by reaction of the corresponding oximes with acryloyl chloride by a method similar to that described in a previous article (14). Styrene (St) and ethyl acrylate (EA) were purified by distillation under reduced pressure.…”

Section: Methodsmentioning

confidence: 99%

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

Ito¹,

Shigeru²,

Kawata³

et al. 1995

Can. J. Chem.

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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)

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“…2 [5]. Tsunooka and Suyama studied the photodegradation of copolymers of MMA and 0-(methacyloyl acetophenone oxime [6]; moreover, using NMR spectra, they clarified the main chain degradation mechanism via the tertiary polymer radical resulting from the photoirradiation of a copolymer of styrene with 0-(methacyoyl)acetophenone oxime [7].…”

Section: Introductionmentioning

confidence: 99%

Photoreaction Mechanism of Benzilmonooxime Methacrylate Polymer and its Model Compounds.

Naito

Fujimura

Kobayashi

et al. 2002

J. Photopol. Sci. Technol.

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University,We studied the mechanism of the photoreaction of benzilmonooxime methacrylate (BIMA) polymers, which are highly photosensitive materials, using stationary photoirradiation and laser flash photolysis (LFP) of the copolymer of methyl methacrylate with BIMA (3.6 mol%). Since the Stern-Volmer relationship for the quenching of the main chain degradation was curved, the reaction proceeded through both excited singlet and triplet states. When the singlet contribution was assumed to be ca. 30 % of the whole reaction, a linear relationship was obtained. In 266, 308 and 355 nm LFP of the BIMA polymer, we could not detect any transient absorption bands. The triplet energy level of the polymer was estimated to be between 274 and 289 kJ mol-` by means of sensitized reactions. To clarify the reaction mechanism, we carried out 266 nm LFP of model compounds: benzilmonooxime phenylacetate (BIPA) and benzilmonooxime diphenylacetate (BIDA). In LFP of BIPA, a transient absorption band was measured at 310 nm immediately after the flash. At 4 µs after the flash, another new band was detected at 460 nm. These bands were assigned to benzyl and benzoyl radicals, respectively. In LFP of BIDA, we measured new transient absorption at 340 nm, which was assigned to diphenylmethyl radical.

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Photodegradation of O‐methacryloyl ketone oxime‐methyl mechacrylate copolymers in the solid phase

Cited by 18 publications

References 11 publications

Photolysis of poly(benzyl methacrylate)s and poly(benzyl acrylate)s in solution and films

Photolysis of poly(benzyl methacrylate)s and poly(benzyl acrylate)s in solution and films

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

Photoreaction Mechanism of Benzilmonooxime Methacrylate Polymer and its Model Compounds.

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