| Micromixing problem is particularly well known in bulk copolymerization. This affects the product qualities. Therefore, in the present work, micromixing effects on styrene-methyl methacrylate, free-radical, bulk copolymerization were studied using a stirred tank reactor.Copolymer composition distributions have long been proposed for measuring micromixing effects. However, the necessary analytical techniques have been found difficult and ambiguous. The reason is interference between molecular weight, sequence length and composition distributions. Hence, first a technique for measuring copolymer composition distribution was developed. A high conversion, methyl-methacrylate copolymer was prepared in batch at 60Mixing experiments were conducted by copolymerizing these monomers in a laboratory scale reactor. Agitation was provided by a four-blade, 45The measured composition distributions of the coploymers were sharp and close to the statistical composition distributions. The average compositions, calcuated from the measured distributions, agreed well with those measured by Using the Atiqullah-Nauman model, the segregation effect was quantified by segregation number. From this an upper limit of the initial striation thickness was calculated. This limit was approximately 1 mm for the present system. |
