EMULSION POLYMERIZATION OF CHLOROPRENE - STUDY OF BRANCHING AND CHAIN TRANSFER-REACTION BY KINETIC-ANALYSIS OF GELATION

A reaction system model was established through an examination of elementary reactions related to the formation of molecular structure such as averaged molecular weight, molecular weight distribution, and branching in the emulsion polymerization of chloroprene. By a kinetic analysis based on this model, a reaction equation was derived corresponding to the reaction system. Polymerization experiments were carried out with various amounts of n-dodecylmercaptan (n-DDM), and gel points were determined. Analyzing the data by the equation obtained above, the following matters were confirmed: (1) n-DDM reacts selectively with the polymer radical to suppress the formation of branching. (2) The selectivity decreases with increases in the amount of charged n-DDM and in the gel point. (3) Competing reactions with formation and suppression of branching in this polymerization sysem were systematically described.