2 сентября, 2015 
Malyar The maximum exothermic temperature reached, the time required for the reaction to attain peak exothermic temperature, and the time of gelation are important factors to be considered when selecting a resin. Reactivity tests provide a method for determining the behavior, uniformity, and curing characteristics of a resin. The use of a resin for a specific application often depends on the reactivity of the resin. Measurements of reactivity are helpful in the evaluation of accelerator, catalysts, and other materials that must be considered for the correct use of the resin.
The inhibitor in the resin counteracts the catalyst which dissociates into free radicals to initiate polymerization during the induction period. As the inhibitor becomes completely consumed, near the end of the interval, the free radicals from the catalyst initiate polymerization. The beginning of the polymerization is evidenced by the exothermic reaction, which causes the temperature of the resin to rise above the ambient bath temperature and the gelation of the resin. Knowing the time it takes for gelation is very helpful in selecting the correct resin for a particular application.
The time period it takes for the temperature of the resin to rise from 5°F above the bath temperature to its maximum is the propagation interval. The rate of polymerization increases until the rate of heat evolution of the resin equals the rate of heat loss to the bath. Polymerization is complete after the peak exothermic temperature is reached. The maximum exothermic temperature together with the propagation interval indicate the rate at which cure is attained.
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