Relative reactivity of phenols and formation of phenolic co-condensed resins

Relative reactivities of various phenols (i.e., m-cresol (m-CR), p-cresol ( p-CR), phenol (Ph), p-t-butylphenol (p-BP), and p-ethylphenol (p-EP)) were determined when the reactivity of m-CR was taken as unity. Go-condensation for m-CR/p-BP/formaldehyde and m-CR/p-EP/formaldehyde systems was done and the reactivity of the phenols and molecular structure were examined. The re activity ratios of p-BP and p-EP to m-CR in the co-condensation were higher than in the condensation. The composition of m-CR/p-BP co-condensed resins was strongly affected by feed composition, molecular weight of co-condense d resin, and degree of reaction when the resin was formed. These features w ere due to differences in reactivity between m-CR and p-BP.