On-line ATR-MIR for real-time quantification of chemistry kinetics along the barrel in extrusion-based processes

This work deals with the development and validation of an on-line infrared spectroscopic set-up for the real time quantification of the melt extrudate during reactive extrusion based processes. The arrangement consists of an infrared spectrophotometer operating in attenuated total reflectance ATR-FTIR, fitted on-line, along the extruder barrel. The setting helps understand the effects of extrusion process parameters and the reaction conversion during development of polymer blends and compound in-processing. The ATR-FTIR spectroscopic probe has been coupled along with an extruder to analyze/understand the process during operation in the MID region of the infrared spectrum. The ATR-FTIR prototype probe was calibrated and validated using off-line measurements. The probe is interfaced to the extruder through to a probe holder unit (PHU), also described herein. The on-line ATR-FTIR measurements were conducted at various locations (L/D) along the length of the extruder. Polymer blends of PP/PA6 in various compositions were investigated and reactive blend of PP-g-AA/PA6 were used to validate the on-line measurements compared to the standard off-line ATR-FTIR analysis. •An on-line ATR-FTIR system was developed for the first time to be used at any location along extruder barrels.•The ATR-FTIR system was validated for both immiscible and reactive polymer blends.•The ATR-FTIR system allows the reaction kinetics to be studied in real-time along the extruder barrel.