By the epoxy group

Radiation-induced Reactions in EAP. To elucidate the reason no vacuum curing effect is observed in EAP, we measured the infrared spectra of EAP films under various conditions. The results are summerized in Figures 3 to 5. The infrared spectrum of a standard EAP film is shown in Figure 3. Absorbance at 910 cm-1 (Aep) caused by the epoxy group and that at 2110 cm-1 (Aaz) caused by the azide group were chosen as measures for concentrations of these groups in the films. 

Allyl glycidyl ether (VI) and glycidyl methacrylate (VII) were used to etherify wood blocks of Pinus sylves-tris and mechanically pulped spruce flbres. The mechanism of the reaction consisted in the chain extension of the wood OH functions by the epoxy groups of VI and VII. The modified samples were characterized by FTIR and C-NMR spectroscopy and by weight gain, which amounted to 7 and 20 per cent for VI and VII, respectively [12]. 

Allyl Glycidyl Ether. This ether is used mainly as a raw material for silane coupling agents and epichlorohydrin mbber. Epichlorohydrin mbber is synthesized by polymerizing the epoxy group of epichlorohydrin, ethylene oxide, propylene oxide, and aHyl glycidyl ether, AGE, with an aluminum alkyl catalyst (36). This mbber has high cold-resistance. 

Epoxy Resins. Epoxy resins (qv) are used to cross-link other resins with amine, hydroxyl, and carboxyHc acid (or anhydride) groups. The epoxy group, properly called an oxkane, is a cycHc three-membered ether group. By far the most widely used epoxy resins in coatings are bisphenol A (BPA) (4,4 -(l-methylethyHdene)bisphenol) [80-05-7] epoxy resins. 

The overall reaction is complicated by the fact that the epoxy group, particularly when catalysed, will react with hydroxyl groups. Such groups may be present due to the following circumstances ... 

Etherification of the epoxy group by hydroxyl groups (Figure 26.8). 

The ion thus produced may itself react with another epoxy-group in a process which forms the first crosslink (Reaction 4.16). This reaction may occur at both ends of the molecule of the diglycidyl ether, so that a crosslinked stmcture can easily be built up from these substances. Reaction becomes complicated by the fact that the epoxy-group may also react with the hydroxy-groups that form as the epoxy ring opens up during cure. Thus the finished resin may contain a complicated array of structures within the three dimensional network. 

Epoxy alcohols were oxidised by TPAP/NMO/PMS/CH Cl without affecting the epoxy group Fig. 2.2 also illustrates the tolerance of the system to alkenes (Tables 2.1 and 2.2) [16]. 

The steric course of epoxidation is governed176,179 essentially by two factors (I) the presence of a free, allylic hydroxyl group at C-2, which promotes the formation of an oxirane ring from the same side as that occupied by the hydroxyl group, and (2) steric hindrance exerted by allylic substituents of other types (CH2OH, CH3, OR, or OCOR) and the alkoxyl group at C-l. Thus, the stereochemical outcome of epoxi-... 

Epoxy resins are thermosetting matrix resins, characterized by the epoxide group [48,193], as shown in Figure 2.9. 

Epoxy resins are cured [29] by reaction of the epoxy group with other functional groups to give linear, branched, or cross-linked products as described in Eq. (2) and in Table 3. 

The epoxidation reaction was monitored by high performance liquid chromatograph (HPCL) on a reverse phase column. The reaction product was identified by IR, proton NMR and carbon-13 NMR spectroscopy. In the IR spectrum, absorption bands at 904 cm-1 and 842 cm-1 were attributed to the epoxy groups (12) peaks at 2.60, 2.78, and 3.15 ppm on the 1H-NMR spectrum were assigned to the three protons of the epoxide group (13) and in the 13C-NMR spectrum, the three glycidyl carbons were identified at 44.5, 50.6, and 70.6 ppm (14). 

Bisphenol A may be replaced in prepn of epoxies by other diphenols, glycols or glycerine, but the resulting resins are of limited utility. The term " epoxy plastic is also sometimes used for other types of high. mol wt compds that contain the epoxy group —C—O—C—, or... 

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