Characterization of surface chemistry and pore structure of H3PO4-activated poly(vinyl alcohol) coated fiberglass

H3PO4-activated poly(vinyl alcohol) coated fiberglass mats (PAPCF) were prepared in air at temperatures below 400 degreesC. The surface chemistry and pore structure of PAPCF were characterized by using N-2 adsorption at 77 K, XPS, DRIFTS, TGA, NaOH uptake and Ag+ adsorption. PAPCF prepared at 300 degreesC yields a high BET surface area (up to 1745 m(2)/g of coating) with a structure composed mainly of micropores. Some oxygen-containing functional groups, such as carboxylic, phenolic hydroxyl groups, and phosphorus species, are incorporated into the PVA-based char coating, with higher activation temperatures leading to increased formation of these groups. Post-treatment with sulfuric acid decreases the content of phosphorus species, but increases that of oxygen-containing groups in the coating. NaOH uptake and Ag+ adsorption show substantial cationic exchange capacity with the PAPCF or acid-treated PAPCF. TGA data show that PAPCF is more thermally stable in air than acid-treated PAPCF. Furthermore, PAPCF activated at 300 degreesC can be regenerated at least 5 times with no change in ion exchange capacity. (C) 2004 Elsevier Ltd. All rights reserved.