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Curing of epoxy resins is an exothermic reaction and in some cases produces sufficient heat to cause thermal degradation if not controlled. [28] Curing does induce residual stress in epoxy systems which have been studied. [29] The induced stresses may be alleviated with flexibilisers. Curing may be achieved by reacting an epoxy with itself ...
Curing is a chemical process employed in polymer chemistry and process engineering that produces the toughening or hardening of a polymer material by cross-linking of polymer chains. [1] Even if it is strongly associated with the production of thermosetting polymers , the term "curing" can be used for all the processes where a solid product is ...
Phases of Epoxy. The green strength of adhesives is the early development of bond strength of an adhesive. It indicated "that the adhesive bond is strong enough to be handled a short time after the adherents are mated but much before full cure is obtained." Usually, this strength is significantly lower than the final curing strength.
Epoxy value derives from the Epoxy equivalent weight (EEW) or Weight Per Epoxide (WPE) and is a measure of the epoxy content of an epoxy resin or epoxy reactive diluent, or glycidyl ether. [1] This is an important parameter as it allows determination of the correct mix ratio of an epoxy system with a curing agent. [ 2 ]
The thermoset matrix is only partially cured to allow easy handling; this B-Stage material requires cold storage to prevent complete curing. B-Stage pre-preg is always stored in cooled areas since heat accelerates complete polymerization. Hence, composite structures built of pre-pregs will mostly require an oven or autoclave to cure.
Adhesives may be broadly divided in two classes: structural and pressure-sensitive. To form a permanent bond, structural adhesives harden via processes such as evaporation of solvent (for example, white glue), reaction with UV radiation (as in dental adhesives), chemical reaction (such as two part epoxy), or cooling (as in hot melt).
There’s an old wives’ tale: If it thunders in the winter, it’ll snow in the next week. Well, we’re hearing thunder ...
The cure package is adjusted specifically for the substrate and the application. The reactive sites—cure sites—are allylic hydrogen atoms. These C-H bonds are adjacent to carbon-carbon double bonds (>C=C<). During vulcanization, some of these C-H bonds are replaced by chains of sulfur atoms that link with a cure site of another polymer ...