Title: Composite Hydrophobic Modification of Expanded Perlite

Author(s): Qiuhui Yan, Haojie Wang, Jieren Luo, Ye Lin, and Yaxin Yang

Publication: Materials Journal

Volume: 119

Issue: 1

Appears on pages(s): 71-78

Keywords: composite modification; expanded perlite (EP); hydrophobic modification; orthogonal test; vacuum modification

DOI: 10.14359/51733148

Date: 1/1/2022

Abstract:
The hydrophobic agents polydimethylsiloxane emulsion (BS 1042) and sodium methyl silicate were used to modify expanded perlite (EP). The effects of the hydrophobic agents and modification methods on the water absorption, thermal conductivity, and bulk density of EP were investigated. First, the orthogonal experiments of the two hydrophobic agents on the modification of EP were designed, and the effects of the drying temperature, hydrophobic concentration, soaking time, and soaking temperature on the performance of EP were analyzed. The optimum modification conditions for the two hydrophobic agents were obtained. Second, under the optimum conditions, the EP was modified by BS 1042 under vacuum conditions and then modified by the atmospheric pressure with sodium methyl silicate, so the composite-modified EP with excellent hydrophobic performance was obtained. The results showed that the water absorption of the composite modified EP was significantly reduced, from 390.1 to 16.2%; the thermal conductivity increased from 0.0532 to 0.0555 w/(m·k), with a small increase of only 4.3%; and the bulk density increased from 51.6 to 59.2 kg/m3, with an increase of 14.7%.