Swelling of Formamide-Montmorillonite Complexes in Polar Liquids

Masanobu Onikata1, Mitsuji Kondo1 and Shoji Yamanaka2
1 Laboratory of Applied Clay Technology (LACT), Hojun Kogyo Co., Ltd., 1433-1 Haraichi, Annaka, Gunma 379-0133, Japan
2 Department of Applied Chemistry, Faculty of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan

Abstract: A new osmotic-swelling system for montmorillonite with formamide (FA) is described. Water and a variety of polar organic liquids were used to swell FA-montmorillonite complexes. The post-swelling behavior of the complex is interpreted in terms of the bi-functionality of FA as an electron donor/ acceptor and the magnitude of the donor number (DN) of the polar liquid relative to that of FA. The FA-montmorillonite complex shows limited swelling of d(001) <2.3 nm for polar liquids with DNs larger than that of FA. In contrast, the FA-montmorillonite complex shows osmotic swelling when the DN of the polar liquid is smaller than that of FA.

Key Words: Donor Number • Formamide • Montmorillonite • Osmotic Swelling • Polar Liquids • Swelling

Clays and Clay Minerals; October 1999 v. 47; no. 5; p. 678-681; DOI: 10.1346/CCMN.1999.0470515
© 1999, The Clay Minerals Society
Clay Minerals Society (www.clays.org)