Amine/anhydride

Pyrimido[l,3]oxazines are reactive toward amines anhydride 121 undergoes ring opening and decarboxylation on treatment with ethanolamine to give the amide 122 <1996MI459>. The reactions of amide 123 <2002MI10> with amines to form pyrimido[5,4- pyrimidines have already been mentioned, while the equivalent process with pyr-imido[5,4- ]oxazinium salt 124 is discussed in CHEC-II(1996) <1996CHEC-II(7)737>. 

Epoxy resins are usually prepared from compounds (or polymers) containing two or more epoxy groups that have been reacted with amines, anhydrides, or other groups capable of opening the epoxy ring and forming thermosetting products. Polymers from monoepoxy compounds have already been described in Sandler and Karo [1]. 

Compounds Z are active hydrogen compounds such as amines, anhydrides, and acids [30]. The curing reaction can also involve homopolymerization catalyzed by Lewis acids or tertiary amines. In most cases, reactions catalyzed by... 

At present, we can say that copolymerization initiated by various salts proceeds by an anionic mechanism, after dissociation of the initiators in the reaction medium. The primary step is the addition of the initiator anion to the epoxide. In the initiation by Lewis bases, i.e. by tertiary amines, initiation involves formation of a primary active centre of an anionic character. This active centre is probably generated by interaction of the tertiary amine with the anhydride and an allyl alcohol. The allyl alcohol can be formed by a base-catalyzed isomerization of the epoxide. In the presence of a proton donor, the formation of active centres is possible through interaction of tertiary amine, anhydride and proton donor without epoxide isomerization. Another way of initiation consists in a direct reaction of epoxide with tertiary amine yielding an anionic primary active centre. We believe that in both kinds of initiation in the strict absence of proton donors, the growing chain end has the character of a living polymer. The presence of proton donors, however, gives rise to transfer reactions. 

Miscellaneous fluorinated precursors, such as amines, anhydrides, oxiranes, alkenes, and carboxylic acids, which are used for special properties. 

The physical and electrical characteristics of the anhydride cured systems are very good over a wide temperature range. Compared to amines, anhydride cured epoxies exhibit better chemical resistance to aqueous acids, but less chemical resistance to some other reagents. When epoxy resins are cured with anhydrides, the product has relatively high heat distortion temperature and low moisture sensitivity. 

ACD is a skin reaction resulting from contact dermal contact with allergens. ACD progresses in two phases. Sensitization is acquired in the initial phase. In the second phase, subsequent exposure elicits an inflammatory reaction. F°1 Large numbers of chemical compounds are known to cause ACD. These include acrylates, aldehydes, amines, anhydrides, etha-nolamines, formaldehyde, resins, metals, pesticides, phenols, phthalate esters, preservatives, isocyanates, solvents, and others. Table 27.4 contains a partial list of these. A more complete list can be found on the webJ21l... 

Amine-anhydride reactions, equilibrium, 115 Anhydride-amine reaction, equilibrium, 115 Anhydride hydrolysis, polyimides, 58,60r,61/62 Aqueous ion extraction, kinetic model, 438-440 Aromatic polyimides applications, 67 properties, 26 structures, 27,28/ use as dielectric materials, 26... 

Sorokin concluded that the formation of the amine-anhydride complex (as proposed by Fischer) did not have a decisive influence on the rate determining step, although it was an intermediate in the catalytic solvolysis of the anhydride. 

Table 5.10. Graft copolymer formation in binary PA/PO blends by amine + anhydride reaction...

PA-Stvrene Covolymer Formation b Amine + Anhydride Reaction... 

Copolymer Formation by Amine + Anhydride or Amine + Carboxylic Acid Reaction Coran and Patel [1983] have shown that the mechanical properties of dynamically vulcanized... 

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