Synthesis of thermosetting phenolic resin and its montmorillonite/silica nanocomposites under alkali-free conditions

Thermosetting phenolic resins are widely used in the field of matrix resin of high-tech materials due to their excellent ablation performance, structural integrity and thermal stability. Traditionally, the synthesis of almost all thermosetting phenolic resin often requires alkali catalyst. These alkali catalysts are difficult to be completely removed from the resin, and their residue will adversely affect thermal performances of these resins to a certain extent. Herein, we described a strategy for the synthesis of boron-modified thermosetting phenolic resin under alkali-free conditions. The key to the success of this process lies in Lewis acidity of borate ester which can promote the condensation of phenol and aldehyde. In addition, in order to further investigate the properties of this resin, its montmorillonite/silica based nanocomposites have been prepared.