Porosity development in chars from thermal degradation of poly(p-phenylene benzobisoxazole)

6 pages, 6 figures, 3 tables. -- Available online 1 November 2008.The main objective of this work was to investigate porosity development in carbonaceous materials formed by thermal degradation of the high thermal stability polymer, poly(p-phenylene benzobisoxazole) (PBO). Two varieties of PBO, as-spun (AS) and high-modulus (HM) were studied. Chars obtained at various polymer decomposition temperatures (selected on the basis of thermogravimetric and differential thermal analysis results) were characterized by elemental analysis, infrared spectroscopy, X-ray diffraction and CO2 adsorption at 273 K. The obtained adsorbents essentially contained narrow micropores, and maximum pore development took place at ca. 1000 K, when the polymer was not yet completely decomposed. At higher temperatures, there is a certain pore widening along with a displacement towards smaller pore sizes, and the pore volume significantly decreases.We thank Dr. Tooru Kitagawa (Toyobo Research Center, Otsu, Shiga, Japan) for kindly providing the Zylon® AS and HM samples. Financial support from the Spanish MEC (projects CTQ2005-01905-C04-02-PPQ and VEM2004-08576) is gratefully acknowledged.Peer reviewe