STUDIES OF SURFACE, STRUCTURAL, AND SORPTION PROPERTIES OF ACID-LEACHED E-GLASS FIBERS

Bulk and surface properties of acid-leached E-glass fiber were investigated by chemical, X-ray, and DTA-TG analyses; SEM observation; and nitrogen adsorption-desorption at -196°C. The amount of nonsilicate constituents extracted from the fiber increased with an increase in the HCl concentration of leachant ([HCl]L). The fibrous form did not change its appearance after leaching, even with a 6 M (1 M = 1 mole dm-3) HCl solution, but SEM observation showed partial disconnection of the fiber. Nitrogen adsorption-desorption curves could be classified into BDDT (Burunauer, Deming, Deming, and Teller) I type for the samples obtained at [HCl]L ≤ 0.5, BDDT II type for the sample at [HCl]L = 1, and BDDT IV type for the samples at [HCl]L ≥ 2. Both BET surface area and pore volume increased with an increase in [HCl]L up to about 2 M, and then decreased at 6 M. The sample obtained at [HCl]L = 0.5 had the characteristic of a markedly high BET c constant (>1.000). V1-t plots suggested the presence of two types of micropores (0.44 nm and about 0.8 nm in hydraulic radius) for the samples obtained at [HCl]L ≤ 2. A mesopore analysis showed the presence of pores ranging from 2 to 6 nm in radius, with a broad size distribution for the samples obtained at [HCl]L ≥ 1. © 1992.