Polyphenylene benzobisoxazole is considered the most tear-resistant synthetic fiber of all. Due to its very low elongation (2.5%), the fiber also achieves a remarkably high modulus of elasticity of 270 GPa. The values of the fiber exceed those of para-aramid in these points by twice. At an LOI of 68, the fibers are practically non-flammable and reach a melting temperature of 650 °C. PBO should be stored and processed in a dry place, since it loses a lot of its strength when exposed to moisture. Finished products in the outdoor area should always be protected from sunlight, since this also has the same effect. The same applies to strong acids.
