Montmorillonite–phenolic resin nanocomposites prepared by one-step in-situ intercalative polymerisation

Montmorillonite (Mt) resol, and Mt–novolac nanocomposites were prepared by one-step in-situ intercalative polymerisation involving the simultaneous modification of the Mt with quaternary ammonium salts (QAS), polymerisation and polymer intercalation. The Mt–polymer nanocomposites were prepared using two types of QAS — with one long (C16) alkyl chain (cetyl trimethylammonium bromide) or with three medium-sized (C8) alkyl chains (tricaprylyl methylammonium chloride) — as well as without a QAS. Intercalated Mt–resol, and Mt–novolac nanocomposites were formed, as confirmed by XRD and STEM. The extent of the intercalation was higher in the Mt–resol nanocomposites and with the cetyl trimethylammonium bromide modified Mt. The presence of the Mt influenced the polymerisation process, which resulted in changes in the molecular structure of the novolac resin, an increased content of p–p linkages and a lower glass transition temperature of the resin.