Synthesis of Telechelic Isotactic Polypropylenes for Circular Polypropylene-like Materials via Chain Transfer Polymerization

While synthesizing circular polymers with telechelic polyolefin building blocks recently emerged as a promising strategy for addressing conventional polyethylenes' sustainability challenges, the lack of telechelic <i>i</i>PP (<i>t</i>PP) with sufficient difunctional purity for polycondensation has been limiting the development of circular polypropylenes with <i>i</i>PP-like structures and properties. Here we described a combined approach of coordinative chain transfer polymerization and transition-metal-catalyzed quenching reaction with various acyl chlorides, affording <i>t</i>PPs with a high difunctional ratio (up to ∼99%) and broad end functional group scope. The steric effect of polymeryl-Zn species and the role of Pd catalyst were revealed by DFT. This method also solved the low difunctional ratio challenge for telechelic polyethylenes. Ester-linked <i>i</i>PPs with <i>i</i>PP-like structure and thermomechanical properties and PE/<i>i</i>PP multiblock copolymers were synthesized by the resulting <i>t</i>PPs.