EMULSION POLYMERIZATION OF BUTYL ACRYLATE .2. EFFECT OF THE INITIATOR TYPE AND CONCENTRATION

The free radical emulsion polymerization of butyl acrylate initiated by a water-soluble initiator (ammonium peroxodisulfate, AP) at 60-degrees-C in the presence of a blend of anionic and non-ionic emulsifiers was investigated. The effect of a blend of water- and oil-soluble initiators (AP + 2,2'-azoisobutyronitrile (AIBN)) is analyzed. Over the interval 2 the rate of polymerization is proportional to the 0,43rd or 0,25th power of the initiator (AP) concentration for runs without or with AIBN. The molecular weights of polymer were found to increase over the low and medium conversion ranges, and the increase is more pronounced at low conversions. Besides, the molecular weight slightly decreases with increasing AP concentration. The addition of AIBN was found to decrease the molecular weight and the rate of polymerization.