Computer Simulation on the Formation of Phenolic Co-Condensation Resins

Reactions for the formation of the phenolic co-condensation resins such as the p-cresol/p-tert-butylphenol/formaldehyde system and o, o-dimethylol-p-cresol/o, o-dimethylol-p-tert-butylphenol system were investigated by computer simulation, and the monomer reactivity ratios and the compositions of the resins were discussed. The computer simulation was carried out under the following assumptions: 1) intramolecular reaction does not occur, 2) the reaction forming a dimethylene ether linkage (-CH2OCH2-) does not occur in the p-cresol/p-tert-butylphenol/formaldehyde system, and 3) the reactivity of a functional group in polymer is independent of the size and molecular weight. In this simulation, the reactivity of each functional group was represented by the probability that the group stored in the computer was selected. It was found that the reactivity of p-cresol was higher than that of p-tert-butylphenol in the addition-condensation reaction. While, the reactivity of o, o-dimethylol-p-cresol was almost equal to that of o, odimethylol-p-tert-butylphenol in the polycondensation reaction. The compositions of these resins were estimated from the values of monomer reactivity ratios obtained by the computer simulation. The resin formed by the additioncondensation reaction contained more of the p-cresol component than ideal copolymer systems (r1=r2=1). Contrary, the resin formed by the polycondensation contained slightly more of the o, o-dimethylol-p-tert-butylphenol component. This may be due to the effect of the p-substituent in the phenolic nucleus on the addition reaction of formaldehyde with a phenolic hydrogen.