Photosensitive epoxy

The/flc-ClRe(CO)3(4,7-Ph2-phen) complex has been demonstrated to be a useful spectroscopic probe in the curing of photosensitive epoxy-based materials [100], Emission spectra obtained from a 0.05-mm thickness film of a mixed epoxy system of bisphenol-A/novalac resin (Interz, SU8) and diglycidyl ether of bisphenol-A (DGEBA) containing cation-generating triarylsulfonium hexafluo-roantimonate salts as photoinitiators (Union Carbide, Cryacure UVI-6974) and... 

This review is intended to provide a survey of the chemistry in these areas, to discuss some applications for photosensitive epoxy systems and to show recent advances. A number of previous reviews are available i" which have described... 

Alternatively, photosensitive epoxy SU-8 can be used as both the core and cladding layer. The refractive index of SU-8 can be reduced by mixing it with at least 2.7 % (by weight) liquid aliphatic epoxy resin DER 353TM from Dow Plastics [13]. The SU-8/aliphatic resin mixture was measured to have n=. 590 at 2 = 633 nm, as opposed to = 1.595 for the unmodified SU-8. The... 

The physico-mechanical, thermal, and adhesion properties of the synthesized polyfunctional PSs are dependent on the nature of functional groups in the aromatic ring. In this case, the following are properties of the chlorohydrin and epoxy groups highest elasticity, resistance to strike, and adhesion properties with carboxyl and olefinics. Furthermore, the—CO—CH=CH-—COOH group was provided new properties such as the photosensitive capability. Functionalized PSs obtained are characterized by their high thermostability, adhesion, and photosensitivity. 

Direct irradiation of substituted 1,4-dihydro-1,4-epoxy naphthalenes gives small quantities of 3-benzoxepins 16 amongst other products.144 146,256 The primary product of this reaction is probably a 3-oxaquadricyclane derivative which can react to give the benzoxepin under thermal conditions. The formation of benzoylindene compounds as the main products from the photochemical rearrangement of l,4-diphenyl-l,4-dihydro-l,4-epoxynaphthalenes has been shown to proceed via the corresponding 3-benzoxepins.146 The irradiation of naphthalene 1,4-oxides in the presence of a photosensitizer did not lead to benzoxepin derivatives.144... 

Hydroxy epoxidation of dienes.2 Photosensitized oxygenation of dienes when catalyzed by titanium(IV) isopropoxide results in an epoxy alcohol, formed by an oxygen transfer from an allylic hydroperoxide. 

Persistent photosensitivity developed in eight men after occupational exposure to hot epoxy resin fiimes. The condition was limited to sites contacted by the resin. Small doses of ultraviolet-A light evoked abnormal reactions consisting of erythema, edema, and papules in the clinically involved skin. Positive photopatch tests were observed to epoxy resin in four subjects and to bisphenol A in all subjects. Another study showed that bisphenol A can be released during the thermal decomposition of epoxy resin in the temperature range of 250-350°C. Photosensitizing activity was explained by the formation of ftee radicals during exposure to ultraviolet-B radiation of bisphenol A vapor, to form a semiquinone derivative of bisphenol A ... 

Allen H, Kaidhey K Persistent photosensitivity following occupational exposure to epoxy resin. Arch Dermatol 115 1307, 1979... 

Since epoxy groups can be attached on differently structured backbones R and combined with other photosensitive groups L, taylor-made photosensitive resin systems can be prepared. From a formal point of view, photocrosslinkable epoxy resins may come in three types ... 

The photoinduced cationic crosslinking of a, co-terminated disiloxanes containing vinyl ether (VEl and VE2) and epoxy flmctional groups (Scheme 1) in dependence of the light intensity and the type of photosensitizers was investigated by means of ceal rime (nfraced (RTIR) spectroscopy and calorimetric measurements. 

The 3 -position of ABA can also be modified while maintaining bioactivity. We synthesized 3 -azido-ABA (5) from ABA via 2 a,3 a-dihydro-2 a,3 a-epoxy-ABA [26]. The biological activity of 5 was equivalent to that of ABA in the inhibition of lettuce seed germination. An investigation of the photosensitivity of 5 is now in progress. 

The third type of composition is exemplified acrylate- and methacrylate-ester derivatives of epoxy resins combined with a photoinitiator 1. Epo prepolymers (e. g., glycidyl methacrylate-allyl glycidyl ether copolymers or Ciba ECN 1299) combined with a photosensitive aryldiazonium compound (e.g.,... 

Several types of photosensitizers have been tested in the silicone epoxy polymer in association with the iodonium salt described above. Benzophenone was found to give poor performance (Fig. 7) whereas 2-ethyldimethoxyanthracene (Fig. 8), chlorothioxanthone (Fig. 9) and isopropyl-thioxanthone (Fig. 10) proved to be highly efficient. One of the major problems with epoxy-silicones is the poor solubility of these photosensibilizors. This problem is currently being studied. 

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