A NEW METHOD OF DEHYDRATION FOR PURE CLAY MATERIALS USING PELDRI II

Abstract--A new chemical, Peldri II, is evaluated as a compound for drying soft clay materials. Peldri II, a fluorocarbon (1,1-difluorotetrachloroethane), is a solid at room temperature and is a liquid above 25 ~ Clay gels are embedded in Peldri II by immersing them in the liquid and allowing it to solidify. Once solidified, Peldri II will sublime, with or without vacuum, to a dry specimen, probably without introducing surface tension. Wyoming montmorillonite saturated in 10 3 M NaC1 and 1 M CaCl2 solutions has been examined to compare preservation ofits initial structure after Peldri II, critical point, and freeze drying techniques. Transmission electron microscopy ofultrathin sections, canning electron microscopy, and mercury intrusion porosimetry techniques were used. No differences were detected between Peldri II and critical point drying methods. Peldri II appears to be a significant improvement as an alternative drying agent for clay materials in studies of their structural properties. It is also very convenient for drying large numbers of samples