The synthesis and characterization of phenolic resin with a high content of dimethylene ether bridges

Abstract

Phenolic resins were synthesized using sodium montmorillonite (MMT) as a catalyst at a concentration of 3%, 5%, and 10%, the reaction time was 24 and 48 h, respectively. The phenolic resin yield was up to 69%. The chemical structure of the resins was determined by NMR, the thermal properties were determined by DSC and TGA, and molar masses were determined by SEC. The resins could not be easily classified as resol or novolac because the most common type of bonding between the aromatic rings was dimethylene ether (DME) bridges. Due to near neutral pH (6.7–7.1), some methylol groups were also present in the structure. Increasing the MMT concentration increased the molar mass of the resin; however, no influence of reaction time was observed. Increased MMT concentration, as well as longer reaction time, decreased the glass transition temperatures, which were very low, in the range of 8–24 °C. Increased content of DME increased the thermal stability of the resins.