High performance fibers based on rigid and flexible polymers

This chapter covers recent developments in the production of well established high performance fibers such as Kevlar, PBO, Spectra and Dyneema fibers and depicts a new super strong M5. The latter fibers have the modulus of 330GPa and tenacity of 5GPa. DuPont de Nemours is currently developing commercial M5 fibers and yarns. A very interesting monomer namely, 2,5-dihydroxyterephthalic is used for making poly{2,6-diimidazo[4,5-b:4',5'-e]pyridinylene-1,4-(2,5-dihydroxy)phenylene} (PIPD). The unique feature of the polymer is that the two hydroxyl groups (on terephthalic acid) can form intermolecular hydrogen bonds and therefore fibrillation, that is often a problem for aramid fibers, is practically eliminated. As a result, M5 fibers have the highest compressive strength among synthetic fibers. Exploratory evaluation of the UV stability of M5 indicated excellent performance in that field. The mechanical properties of the new fiber make it competitive with carbon fiber in most applications - in light, slender, load bearing stiff advanced composite components and structures.