Online monitoring of styrene butadiene copolymerization, including a final coupling reaction
Michael F. Drenski, Wayne F. Reed, Fluence Analytics
Piotr Kozminski, Terry Hogan, Bridgestone Research Americas (Akron, OH)
Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP) was used to continuously measure the anionic polymerization of styrene butadiene rubber (SBR) at the 20 L scale. The following application note details ACOMP successfully demonstrating that it can track conversion, along with weight average molecular weight (Mw), and low and high shear reduced viscosities (RV). After the initial reaction, the effects of the coupling agent were directly monitored by ACOMP. This showed a doubling in Mw over time and increases in RV commensurate with what one expects for random coils in a good solvent.
ACOMP yields continuous data on these important characteristics of the reaction and resulting polymers. These polymer properties include conversion, molecular weight, reduced viscosity, and shear thinning viscosity. It is important to note that ACOMP is not a chromatographic method. Thus, it yields continuous average values, such as Mw, rather than the intermittent molecular weight distributions (MWD) provided by GPC. The work below, conducted in conjunction with Bridgestone Research Americas, outlines results obtained from the application of ACOMP to SBR reactions.