Some Attempts at Introducing Flexibility Into Phenolic Resins

Phenolic resins were modified by either forming copolymers with p-alkylated phenols or by etherification, the goal being to obtain materials with enhanced flexibility. The phenolic copolymers were prepared at various mole ratios of phenol to p-alkylated phenol. The p-alkylated phenols chosen were p-cresol, 4-t-butyl phenol, and nonylphenol, and the polymerizations were carried out under basic conditions. None of the resulting cured resins had increased flexibility. A second series of experiments involved etherification of the hydromethylphenol prepolymer with various polyhydroxyl compounds, including ethylene glycol and glycerin. The resulting resins did show some enhanced flexibility, which depended on the number of hydroxyl groups in the alcohol and on the pH used during the etherification reaction.