Enhanced Recyclability\nof Thermoplastic Elastomer\nToughened Polyamide 6 via Tri- and Multi-epoxy-Terminated POSS Hybrid\nAdditives

Although widely used polymers, such as polyethylene (PE)\nand polypropylene\n(PP), are easily recyclable, complex engineering polymer blends used\nin the automotive sector involve recycling challenges at the end of\nlife. This study explores the alterations in the properties of compatibilized\nPA6/TPE blends under multiple thermomechanical recycling conditions,\nespecially for the automotive industry in underhood applications.\nThe compatibilization of PA6/TPE blends was achieved through the incorporation\nof polyhedral oligomeric silsesquioxane (POSS) nanoparticles, specifically\nutilizing variants with three and multiple epoxide functional groups\n(TriEpPOSS and MultEpPOSS, respectively) in their cage structures.\nFollowing each recycling step, the blends were pelletized and injection-molded\nto characterize their morphological, rheological, mechanical, and\nthermomechanical properties. The findings revealed that the addition\nof TriEpPOSS significantly improved all properties of PA6/TPE blends\nthroughout successive extrusion cycles. For instance, significant\nenhancements in Izod impact strength were achieved through the incorporation\nof TriEpPOSS into the PA6/TPE blend across multiple extrusion cycles.\nNotably, the 80PA6/20TPE blend with 1 wt % TriEpPOSS demonstrated\na remarkable 685% increase in Izod impact strength compared to the\nsame blend without TriEpPOSS following the fourth extrusion cycle.\nConversely, the incorporation of MultEpPOSS slightly reduced the rheological\nand mechanical properties after each extrusion cycle. Nonetheless,\nit was observed that all properties, particularly rheological characteristics,\nwere superior in blends compatibilized with MultEpPOSS compared to\nboth TriEpPOSS-compatibilized and noncompatibilized blends, owing\nto the heightened reactivity of MultEpPOSS toward PA6.