Real-time Fiber Optic Monitoring of Solution and Suspension Polymerization Processes

A novel fiber optic mid-IR probe equipped with an Attenuated Total Reflectance (ATR) and a transmission (TR) head was developed for the real-time monitoring of polymerization processes and ancillary reactions. The TR head can monitor very low concentrations (0.1 mmol/L). The probe was used to monitor both homogeneous living carbocationic isobutylene, styrene and p-tert/-butylstyrene homopolymerizations and sequential block copolymerizations, phenylacetylene polymerization, ring opening metathesis polymerization (ROMP) of 1,5- cyclooctadiene, and heterogeneous carbocationic isobutylene-isoprene copolymerizations by following the disappearance or appearance of IR bands characteristic of the monomers and polymers. Due to the sensitivity of the TR probe, overtone signals could also be monitored. Reactions related to the polymerization processes such as initiation, isomerization and complexation were also monitored. The novel monitoring methods gave insight into the mechanism and kinetics of the relevant processes, providing a powerful tool for macromolecular engineering.