STUDY ON THE CONTROL OF MOLECULAR WEIGHTDISTRIBUTION OF THE NOVALAC OLIGOMERTHROUGH PHASE SEPARATING

摘要

This report presents a method to control thed molecular weight distribution of the novalacoligomer by modulating the stirrer pattern during the systhesis process. Because the molecular weightdistribution of the novalac oligomer is direct related to the melt viscosity and the cured structure, ithas great influence on the process and performance of the novalac resin in many cases. How tocontrol the molecular weight and its contribution of the widely used novalac resin attracts much moreattentions in the field of phenolic resin production. The synthesis reaction mechanism of the novalacis commonly known as condensation polymerization. It is difficult to control the moleculardistribution of the novalac resin in a narrow scope, especially when the molecules are in such a sizeof several phenol rings. In this paper, a model was set up to simulate the phase separating in thecourse of the novolac reaction , according to the model, the process is greatly improved.Consequently, the novolac resin of perfectly distributing molecular weight was prepared, its mainlyconcluded trimer and tethemer.