Progresses on Sensitization of Cationic Photoinitiators

doi:10.7517/j.issn.1674-0475.2013.01.009

Abstract

Abstract: The curing rate and quantum efficiency of cationic photoinitiators are relatively low because the UV absorption of the photoinitiators ranges from 250 nm to 300 nm normally and does not match with the wavelength of light from UV light sources. To make the absorption red-shift, many efforts have been devoted onto the photosensitization of the photoinitiators. The achievements on the sensitization of the cationic photoinitiators have been summarized here. The sensitization is mainly based on the mechanisms as energy transfer, oxidation of free radical,electron transfer via exciplexes and addition fragmentation reaction. The methods adopted for the sensitization include adding photosensitizer,expanding molecular conjugation and attaching chromophore. The development of the photoinitiators and photosensitizers has been outlined and the applications of novel cationic photoinitiators and photosensitizers have been forecasted.

Key words: UV curing, cationic photoinitiator, photosensitizer, sensitization

CLC Number:

ZHANG Hong, LI Jian-xiong, LIU An-hua. Progresses on Sensitization of Cationic Photoinitiators[J]. Imaging Science and Photochemistry, 2013, 31(1): 69-78.

References

[1] 魏杰,金养智. 光固化涂料[M]. 北京: 化学工业出版社, 2005. 52-59. Wei J, Jin Y Z. Photocurable Coatings[M]. Beijing: Chemical Industry Press, 2005. 52-59.
[2] 王涛,黄毓礼,师树简. 芳茂铁阳离子聚合光引发剂引发活性研究[J]. 高等学校化学学报,2003,(4): 735-738. Wang T, Huang Y L, Shi S J. Studies on the photosensitivity of cationic polymerization photoinitiator BF₄^-[J]. Chemical Journal of Chinese Universities, 2003,(4): 735-738.
[3] 周健,张秋禹,张和鹏. 鎓盐类阳离子光引发剂的研究进展[J]. 材料导报,2011, 25(1): 16-21. Zhou J, Zhang Q Y, Zhang H P. The development of onium salt cationic photoinitiators[J]. Materials Review, 2011, 25(1): 16-21.
[4] 张变香,魏保利. 紫外阳离子光引发剂及其发展动态[J]. 中国涂料,2011, 26(4): 31-54. Zhang B X, Wei B L. UV cationic photo-initiator and the development trend[J]. China Paint, 2011, 26(4): 31-54.
[5] Crivello J V, Ahn J. Synthesis and characterization of second-generation S,S-dialkyl-S-(dimethylhydroxyphenyl)sulfonium salt photoinitiators[J]. Journal of Polymer Science Part A: Polymer Chemistry, 2003, 41(16): 2556-2569.
[6] 凌华招,谢川. 改善鎓盐类阳离子光引发剂光敏性的研究概况[J]. 信息记录材料,2005,(3): 27-30. Ling H Z, Xie C. Development of enhancing photosensitivity of onium salts cationic photoinitiators[J]. Information Recording Materials, 2005,(3): 27-30.
[7] Dektar J L, Hacker N P. Comparison of the photochemistry of diarylchloronium, diarylbromonium, and diaryliodonium salts[J]. The Journal of Organic Chemistry, 1991, 56(5): 1838-1844.
[8] Dektar J L, Hacker N P. Photochemistry of diaryliodonium salts[J]. The Journal of Organic Chemistry, 1990, 55(2): 639-647.
[9] Dektar J L, Hacker N P. Triphenylsulfonium salt photochemistry. new evidence for triplet excited state reactions[J]. The Journal of Organic Chemistry, 1988, 53(8): 1833-1835.
[10] Crivello J V, Lam J H W. Diaryliodonium salts. a new class of photoinitiators for cationic polymerization[J]. Macromolecules, 1977, 10(6): 1307-1315.
[11] Yaci Y, Reetz I. Externally stimulated initiator systems for cationic polymerization[J]. Progress in Polymer Science, 1998, 23(8): 1485-1538.
[12] Akhtar S R, Crivello J V, Lee J L. Synthesis of aryl-substituted sulfonium salts by the phosphorus pentoxide-methanesulfonic acid promoted condensation of sulfoxides with aromatic compounds[J]. The Journal of Organic Chemistry, 1990, 55(13): 4222-4225.
[13] Yagci Y, Schnabel W. New aspects on the photoinitiated free radical promoted cationic polymerization[J]. Makromolekulare Chemie. Macromolecular Symposia, 1992, 60(1): 133-143.
[14] Timpe H J, Rajendran A G. Light-induced polymer and polymerization reactions-42. A kinetic study of cationic photopolymerization with (benzoin derivative)/(onium salt) systems[J]. European Polymer Journal, 1991, 27(1): 77-83.
[15] Kahveci M U, Tasdelen M A, Yagci Y. Photochemically initiated free radical promoted living cationic polymerization of isobutyl vinyl ether[J]. Polymer, 2007, 48(8): 2199-2202.
[16] Narewska J, Strzelczyk R, Podsiady R. Fluoflavin dyes as electron transfer photosensitizers for onium salt induced cationic photo polymerization[J]. J. Photochem. Photobiol. A, 2010, 212: 68-74.
[17] Cook W D, Chen F. Enhanced photopolymerization of dimethacrylates with ketones, amines, and iodonium salts: the CQ system[J]. Journal of Polymer Science Part A: Polymer Chemistry, 2011, 49(23): 5030-5041.
[18] Johnen N, Kobayashi S, Yagci Y, et al. Substituted vinyl bromides as photoinitiators for cationic polymerizations[J]. Polymer Bulletin, 1993, 30(3): 279-284.
[19] Dossow D, Qin Q Z, Hizal G, et al. Photosensitized cationic polymerization of cyclohexene oxide: a mechanistic study concerning the use of pyridinium-type salts[J]. Polymer, 1996, 37(13): 2821-2826.
[20] Cho J, Hong J. Photocuring kinetics for the UV-initiated cationic polymerization of a cycloaliphatic diepoxide system photosensitized by thioxanthone[J]. Eur. Polym. J., 2005, 42(1): 367-374.
[21] Cho J, Kim E, Kim H, et al. An investigation of the surface properties and curing behavior of photocurable cationic ?lms photosensitized by anthracene[J]. Polymer Testing, 2002, 21: 781-791.
[22] Crivello J V. Benzophenothiazine and benzophenoxazine photosensitizers for triarylsulfonium salt cationic photoinitiators[J]. Journal of Polymer Science Part A: Polymer Chemistry, 2008, 46(11): 3820-3829.
[23] Crivello J V, Bulut U. Curcumin: a naturally occurring long-wavelength photosensitizer for diaryliodonium salts[J]. Journal of Polymer Science Part A: Polymer Chemistry, 2005, 43(21): 5217-5231.
[24] Gomurashvili Z, Crivello J V. Phenothiazine photosensitizers for onium salt photoinitiated cationic polymerization[J]. Journal of Polymer Science Part A: Polymer Chemistry, 2001, 39(8): 1187-1197.
[25] Crivello J V, Jang M. Anthracene electron-transfer photosensitizers for onium salt induced cationic photopolymerizations[J]. Journal of Photochemistry and Photobiology A: Chemistry, 2003, 159(2): 173-188.
[26] Crivello J V, Lee J L. Photosensitized cationic polymerizations using dialkylphenacylsulfonium and dialkyl(4-hydroxyphenyl)sulfonium salt photoinitiators[J]. Macromolecules, 1981, 14(5): 1141-1147.
[27] Bulut U, Balan A, Caliskan C. Benzotriazole derivatives as long wavelength photosensitizers for diaryliodonium salt initiators[J]. Journal of Polymer Science Part A: Polymer Chemistry, 2011, 49(3): 729-733.
[28] Yaci Y, önen A. An allylic pyridinium salt: radical promoted latent thermal catalyst for cationic polymerization[J]. Journal of Polymer Science Part A: Polymer Chemistry, 1996, 34(17): 3621-3624.
[29] Denizligil S, Yagci Y, Mcardle C. Photochemically and thermally induced radical promoted cationic polymerization using an allylic sulfonium salt[J]. Polymer, 1995, 36(16): 3093-3098.
[30] Reetz I, Bacak V, Yagci Y. Addition fragmentation reactions for cationic polymerization using a novel allyloxy-picolinium salt[J]. Polymer International, 1997, 43(1): 27-32.
[31] Crivello J V, Kong S. Long-wavelength-absorbing dialkylphenacylsulfonium salt photoinitiators: synthesis and photoinduced cationic polymerization[J]. Journal of Polymer Science Part A: Polymer Chemistry, 2000, 38(9): 1433-1442.
[32] Crivello J V, Lam J H W. Photoinitiated cationic polymerization by dialkylphenacylsulfonium salts[J]. Journal of Polymer Science: Polymer Chemistry Edition, 1979, 17(9): 2877-2892.
[33] Crivello J V, Lam J H W. Photoinitiated cationic polymerization with triarylsulfonium salts[J]. Journal of Polymer Science: Polymer Chemistry Edition, 1979, 17(4): 977-999.
[34] Peter Pappas S, Tilley M G, Pappas B C. Anthracene-bound sulfonium salts: highly efficient photoinitiators for cationic polymerization: a new synthesis of sulfonium salts which avoids the use of silver salts[J]. Journal of Photochemistry and Photobiology A: Chemistry, 2003, 159(2): 161-171.
[35] 洪啸吟,Pappas S P. 分子内敏化鎓盐的合成及光敏性研究[J]. 感光科学与光化学,1993, 11(3): 256-263. Hong X Y, Pappas S P. Studies on synthesis and photoactivity of some onium salts with built-in photosensitizer[J]. Photographic Science and Photochemistry, 1993, 11(3): 256-263.
[36] Yurteri S, Onen A, Yagci Y. Benzophenone based addition fragmentation agent for photoinitiated cationic polymerization[J]. European Polymer Journal, 2002, 38(9): 1845-1850.
[37] Onen A, Yagci Y. Synthesis of a novel addition-fragmentation agent based on Michler's ketone and its use as photo-initiator for cationic polymerization[J]. Polymer, 2001, 42(16): 6681-6685.
[38] 阳年发,曹靖,杨利文. 自由基和阳离子杂化光固化引发剂及其制备方法和用途. 中国专利,02114033.2. 2002-10-30. Yang N F, Cao J, Yang L W. Synthesis and application of free radical and cationic hybrid photoinitiator. China patent, 02114033.2. 2002-10-30.
[39] Kreutzer J, Demir K D, Yagci Y. Synthesis and characterization of a double photochromic initiator for cationic polymerization[J]. European Polymer Journal, 2011, 47(4): 792-799.