PBI is manufactured from tetra-aminobiphenyl and diphenyl isophthalate, which undergo a dry spinning process that utilizes dimethyl acetamide as the solvent. The result is a long-chain aromatic polymer featuring recurring imidazole groups. The fibers formed from this polymer exhibit a number of highly desirable characteristics, such as no melting point and inflammability. The stiff fibers also maintain their integrity when exposed to high heat and are mildew, abrasion, and chemical resistant.