Optimization of the process variables for the synthesis of spherical novolac-typed resin by dispersion polycondensation of 2-phenoxyethanol with formaldehyde using response surface methodology

Spherical novolac-typed resin (SNR) was synthesized by the dispersion polycondensation of 2-phenoxyethanol (PE) with formaldehyde. The effect of the process variables, including the molar ratio of formaldehyde to 2-phenoxyethanol (F/P), the stabilizer concentration, the amount of catalyst, the reaction temperature and the agitation speed, on the particle size (Dn), the particle size distribution (PDI) and sphericity index (SI) was investigated by using central composite rotatable design (CCRD) and response surface methodology (RSM). The optimum reaction parameters predicted for the synthesis of SNR were as follows: the molar ratio of F/P 2.44:1, the stabilizer concentration 2.96%, the amount of catalyst 6.29 ml, the reaction temperature 60.3 °C, and the agitation speed 789 rpm. The values of Dn, PDI and SI obtained under the optimum reaction parameters were 0.693 mm, 1.005 and 0.997, respectively. The experimental values of the response variables were in good agreement with the predicted values.