What type of chemical reduces the cross-linking rate of resin to increase working time?

The correct answer is an inhibitor. An inhibitor is a type of chemical that slows down or prevents the chemical reactions that lead to the curing or cross-linking of resins. When an inhibitor is added to a resin formulation, it extends the working time by delaying the onset of hardening, allowing for more manipulation or adjustment of the material before it sets. This is especially important in composite manufacturing where precise application and adjustment can be crucial for the desired properties of the final product.

In contrast, accelerators are chemicals that speed up the curing process, while catalysts facilitate the reaction but don’t alter the total amount of cure; they are not designed to extend working time. Modifiers are used to change properties of the resin, such as flexibility or strength, but do not specifically serve the purpose of increasing the working time by reducing cross-linking. Understanding these roles helps in selecting the right additives for specific applications in composites and maximizing the utility of the materials used.