Synthesis and characterization of resol type phenolic resin/layered silicate nanocomposites

Resol type phenolic resin/layered silicate nanocomposites (RPLSNs) are prepared by melt intercalation using various layered silicates such as sodium montmorillonite (MMT) and omega -amino acid modified montmorillonites (C3M, C6M, and C12M). The most hydrophilic MMT is the most compatible with the resol type phenolic resin (KL) at the beginning of cure due to the initial hydrophilicity of KL with many methylol groups. However, HL is deintercalated out of extragallery of MMT during the cure since the HL lose hydrophilicity by the depletion of methylol groups. It is found that the C6M has the best miscibility with KL at the entire cure stage. The KLC6M system has the best mechanical properties, due to the end-tethered structure formed by the reaction between the organic modifier (carboxylic acid) of C6M and the methylol group of KL, as well as the excellent dispersion of silicate layers. RPLSNs have similar thermal stability to the neat phenolic resin.