Hydrogen-bond driven intercalation of synthetic fluorinated mica by poly(oxypropylene)-amidoamine salts

A series of organic silicate hybrids were synthesized through ion exchange reactions between the poly(oxypropylene)-amidoamine salts and the following two clays: synthetic fluorinated mica (Mica) and sodium montmorillonite (MMT). The amidoamines were prepared from the oligomerization of poly(oxypropylene)-diamine of 400 g/mol MwMw (POP400) and dicarboxylic acid (adipic or sebacic acid) at various molar ratios of 2:1, 3:2 and 4:3. The organo-clay hybrids can achieve a high organic embedment of up to 70 wt%, exceeding the theoretical amount (61 wt%) as calculated from the clay cation exchange capacity (CEC = 120 mequiv./100 g). The intercalation profile indicated a continuing increase in basal spacing from 5.8 to 7.8 nm for Mica and 5.2 to 7.1 nm for MMT when using the excess amount of POP400-sebacamide as the intercalating agent. The excess intercalation was attributed to the presence of hydrogen bonding which affect the POP-amidoamine self-aggregation within the confinement.