Extrusion International 5-2026

29 Extrusion International 5/2026 EXTRUSION TECHNOLOGIES Fakuma, 12.-16.10.2026 HALL A6, BOOTH 6202 Visit us in Friedrichshafen, Germany! maag.com NEXT LEVEL SOLUTIONS Integrated Systems for Polymer Processing MAAG Group is the Partner for the Polymer Processing Industry worldwide. All of our integrated solutions from Pump and Filtration Systems to Pelletizing and Pulverizing systems to Recycling Systems have an outstanding performance for demand- ing customer requirements. Going Beyond Average Properties to Validate Reactive Extrusion Upcycling By Lucivan Barros , Ph.D., Senior Applications Scientist, Thermo Fisher Scienti c Polypropylene (PP) is among the most widely used polymers, and much of it gets wasted when compared to the amount that is recycled. It degrades during reprocessing, then gets written off as t only for downcycling. Chain scission lowers molecular weight and cuts performance, so recycled PP lands in low-value parts. U pcycling through reactive ex- trusion offers a way forward, giving this waste a second life. In- stead of reprocessing PP waste, this approach blends PP waste into a matrix driving chemical reaction at the matrix phase interface inside the extruder. Proving it worked is the harder problem, and that takes chemical analysis that goes beyond average properties, because aver- ages are where an upcycled blend hides its weak spots. Why a recovered tensile number alone is not proof of upcycling We tested this on recycled PP and polyamide 12 (PA12), using polypropylene grafted with maleic anhydride (PP-g-MA) as a compati- bilizer. The anhydride groups react with the amine end groups of PA12, forming a di-block copolymer at the interface that lowers interfacial ten- sion and holds the phases together. A non-reactive 50/50 blend lost tensile strength, dropping to about 32 MPa against roughly 42 MPa for neat PA12. This indicates a weak interface between phases, acting as weak point where the part fails under low mechanical load. In con- trast, the reactive blend recovered to nearly 42 MPa while carrying 50% recycled content due to the ef - fective interfacial adhesion. A ma- terial that is half waste performed like a virgin high-performance polymer. That is why I want to challenge how the industry reads success. A recovered tensile number is neces- sary, but it does not alone prove up- cycling. In an immiscible blend, the interface is where the part lives or dies, and a single average tells you almost nothing about it. To evalu- ate the improved mechanical prop- erties the morphology needs to be looked closer. Chemical maps of the non-reactive blend (A) and reactive blend (B), demonstrating signi cantly less blending variation in the reactive blend sample