Which fiber type will dissolve when formic acid is applied?

The fiber type that dissolves when formic acid is applied is wool. Wool is a natural protein fiber composed mainly of keratin, which can be hydrolyzed by strong acids like formic acid. When wool is exposed to formic acid, the acid breaks down the protein chains, resulting in the fiber dissolving.

Cotton, being a cellulose-based fiber, does not dissolve in formic acid but can be modified with it under specific conditions. Nylon, a synthetic polyamide, is resistant to formic acid, as the acid does not have the ability to break down its chemical structure. Acrylic, another synthetic fiber, is also not affected in the same manner by formic acid.

Understanding the chemical reactions between different fiber types and various solvents or acids is essential in the upholstery and fabric cleaning field, as it informs cleaning and restoration methods appropriate for the material being treated.