Poly(Para-Phenylene) Fibers-Characterization And Preliminary Data For Conversion To Carbon Fiber

Given the exceptionally high thermal stability of poly (para-phenylene) (PPP) among linear polyaromatics, it is expected that PPP fibers will have myriad applications. In this study, PPP fibers were obtained starting from the enzymatic dihydroxylation/reduction of benzene to 5,6-cis-dihydroxycyclohexa-1,3-diene, followed by esterification, polymerization, and thermal aromatization. Polymer precursor was characterized in terms of its thermal and rheological properties. High levels of aromatization were achieved, and the obtained PPP fibers were mostly para-linked. Carbonization of PPP fibers by pyrolysis was studied at different temperatures (600-1500 degrees C). Fourier transform infrared and Raman spectroscopy results showed that PPP transformed into disordered carbon at temperatures above 800 degrees C, similarly to commercial carbon fiber (CF). Scanning electron microscopy analysis showed that PPP fibers and CFs had smooth surfaces, were nonporous, and retained their original fiber shape during the aromatization and carbonization steps. Our research highlights the high potential of using PPP as an alternate precursor to CF.