METHOD OF CONTROLLING MOLECULAR-WEIGHT DISTRIBUTION DURING POLYMERIZATION PROCESS

摘要

PROBLEM TO BE SOLVED: To provide a method of the rigorous control of the molecular weight, molecular weight distribution and melt flow index of a polymer. SOLUTION: The method involves the removing of polymerized monomers and a flow of the product containing monomers from a monovinyl aromatic polymerizing apparatus, with the flow of the product being introduced into an up-flow heat exchanger and the introduction being carried out in the presence of such an initiator as a peroxide to give an influence on the polymerization of the above monomer occurring inside the above upflow heat exchanger. The initiator may contain a low-temperature initiator and a high-temperature initiator and may have the ratio of the above high-temperature initiator to the above low-temperature initiator ranging from about 0:600 to about 50:600.