Synthesis of an Addition-Crosslinkable, Silicon-Modified Polyolefin via Reactive Extrusion Monitored by In-Line Raman Spectroscopy

• Published in: Polymers Vol. 13; no. 8; p. 1246
• Main Authors: Ulitzsch, Steffen, Bäuerle, Tim, Stefanakis, Mona, Brecht, Marc, Chassé, Thomas, Lorenz, Günter, Kandelbauer, Andreas
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 12.04.2021; MDPI
• Subjects: Biomedical materials; Calibration; Cosmic rays; Data analysis; Design of experiments; ethylene-propylene copolymer (EPM); Extrusion; Gas flow; Grafting; hydride modification; NMR; Nuclear magnetic resonance; Polymers; Polyolefins; Principal components analysis; Process controls; Propylene; Raman spectroscopy; reactive extrusion; response surface analysis; Response surface methodology; silane modification; Software; Spectrum analysis; Technology assessment; Variance analysis; vinyltetramethyldi-siloxane (VTMDS); United States > US; Germany; ethylene-propylene copolymer (EPM); reactive extrusion; silane modification; hydride modification; vinyltetramethyldi-siloxane (VTMDS); response surface analysis; grafting; in situ analysis; process analytical technology (PAT); in-line spectroscopy
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym13081246

We present the modification of ethylene-propylene rubber (EPM) with vinyltetra-methydisiloxane (VTMDS) via reactive extrusion to create a new silicone-based material with the potential for high-performance applications in the automotive, industrial and biomedical sectors. The radical-initiated modification is achieved with a peroxide catalyst starting the grafting reaction. The preparation process of the VTMDS-grafted EPM was systematically investigated using process analytical technology (in-line Raman spectroscopy) and the statistical design of experiments (DoE). By applying an orthogonal factorial array based on a face-centered central composite experimental design, the identification, quantification and mathematical modeling of the effects of the process factors on the grafting result were undertaken. Based on response surface models, process windows were defined that yield high grafting degrees and good grafting efficiency in terms of grafting agent utilization. To control the grafting process in terms of grafting degree and grafting efficiency, the chemical changes taking place during the modification procedure in the extruder were observed in real-time using a spectroscopic in-line Raman probe which was directly inserted into the extruder. Successful grafting of the EPM was validated in the final product by H-NMR and FTIR spectroscopy.