Dynamic Semicrystalline Networks of Polypropylene with Thiol-Anhydride Exchangeable Crosslinks

Thermoplastic polyolefins (TPOs) crosslinked by dynamic covalent bonds (xTPOs) have the potential to be most utilized class of polymer in world, with applications ranging from household and automotive biomedical devices additive manufacturing. xTPO combines benefits thermoplastics thermosets a “single material” potentially avoids their shortcomings. Here, we describe new two-stage reaction extrusion strategy TPOs backbone consisting inert C–C (polypropylene, PP), thiol-anhydride, dynamically crosslink PP through thiol-thioester bond exchange. The degree crosslinking determines rubber plateau modulus above melting point plastic: at 200 °C increases zero melt 23 kPa 6% crosslinking, 60 20%, 105 40%. overall mechanical strength solid plastic is 25% higher compared original PP, gel fraction reaches 55%. Finally, demonstrate that material readily reprocessable (recycled, remolded, rewelded, 3D printed).