Type of Curative

Each type of curative on the market has a different factor (molecular weight/functionality). This value changes according to the basic chemical composition and the fundamental activity of the curative for example ... [Pg.81]

Similar work can be carried out during the curing by studying the reaction rate between the curative and the prepolymer. The "-NCO" band at 2270 cm4 will decrease and the urethane or the urea bands will increase, depending on the type of curative used. [Pg.191]

The weak Br-Br bond breaks to form two bromine radicals. This can be represented by two single-headed curly arrows, fish hooks, to indicate that only one electron is moving. This is virtually all you will see of this special type of curly arrow until we consider the reactions of radicals in more detail (Chapter 39). When you meet a new reaction you should assume that it is an ionic reaction and use two-electron arrows unless you have a good reason to suppose otherwise. [Pg.126]

Table 7.5 gives selected recipes for vulcanization by phenolic curatives, benzoquinone-dioxime, or m-phenylenebismaleimide. Vulcanizates based on these types of curatives are particularly useful in cases where thermal stability is required. [Pg.367]

Lewis and Bronsted acids, activate the epoxy ring toward ring opening by various nucleophilic species, most often hydroxyl or other epoxy groups (Eqs. 2-4). Both types of curatives can take the form of catalytic species, such as tertiary amines and Lewis acids, or coreactants, such as primary amines, mercaptans, and dicarboxylic acids. When the curatives are catalytic species, the properties of the cured adhesive are due primarily to the epoxy resin and the stability/activity of the catalyst in the resin under cure conditions. Coreactant curatives offer much greater latitude in choosing the final cured adhesive properties because the physical characteristics of the... [Pg.115]

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