Morphology and curing behaviors of phenolic resin-layered silicate nanocomposites prepared by melt intercalation

The melt intercalation and curing behavior of phenolic resin (P1) were inve stigated by use of layered silicates, such as pristine montmorillonite (PM) , dodecylammonium-modified montmorillonite (C12M), octadecylammonium-modifi ed montmorillonite (C18M), benzyldi-methyloctadecylammonium-modified fluoro hectorite (C18BH), and hexamethylenetetramine (HMTA), as curing agents. It was found by X-ray diffraction that the uncured phenolic resin was intercal ated into PM, C18M, and C18BH. Cured phenolic resin-layered silicate nanoco mposites were prepared by two methods: one was the sequential process of in tercalation and curing (IC, the suffix of sample code), and the other was t he simultaneous process of mixing and curing (MC). The intercalated structu res were preserved in cured P1C18BH but not in cured P1C18M, i.e., the phen olic resin intercalated in C18M was deintercalated when it was cured. It wa s suggested that the intercalated structure of P1C18BH was more stable in t he curing process than that of P1C18M due to chemical affinity derived from the favorable interaction between the phenolic resin and intercalant-conta ining benzene ring. Transmission electron micrographs showed that a splitte d-stacked structure was formed in the samples of P1PMMC and P1PMIC, indicat ing the phenolic resin did not intercalate the PM. Conclusively, the modifi cation of layered silicate and the resulting interaction between organic mo difier and phenolic resin played an important role in determining the stabl e nanostructure and the final morphology of phenolic resin-layered silicate nanocomposite.