(531c) Formation of Poly(para-phenylene) Fibers

Poly(para-phenylene) (PPP) is a rigid-rod linear polyaromatic polymer having a unique combination of physical properties including low density, high mechanical strength, high thermal stability and high electrical and chemical resistance. These properties make PPP ideally suited for biomedical applications, electrode materials in electrochemical cells and in light-weight rechargeable batteries as well as high-performance engineering materials in extreme environments. PPP in the form of a film or fiber can be prepared with the precursor method where the polymer precursor is aromatized at high temperature under tension. To date, PPP film has been formed in small quantities and the fiber has not been produced. In this research, we synthesized PPP fiber starting with polymerization of 5,6-cisdihydroxycyclohexa-1,3-diene to form the polymer precursor and then aromatization. PPP is not soluble in any solvent and hence cannot be spun, therefore the soluble polymer precursor is used to form fibers that can be aromatized under tension to form PPP. Fibers were directly pulled out from the polymer precursor and aromatized at 400º C under inert atmosphere. The products were characterized using ¹H NMR, HPLC, ATR-FTIR, UV, TGA and RAMAN. The precursor polymer has been characterized by measuring its rheological properties. The effect of process-induced morphology during aromatization on the properties of PPP was studied.