Facile Synthesis of α,ω-Dihydroxy Telechelic Macromonomers From Ethylene and α-Olefins for Recyclable Alternating Block Copolymers.

AA-type α,ω-dihydroxy telechelic polyolefins (tPOs) are key macromonomers for the step-growth construction of circular polyolefin(-like) materials and, in particular, block-level sequence-controlled olefin block copolymers (OBCs), yet a general route to α,ω-dihydroxy tPOs directly from commodity ethylene/α-olefins has remained inaccessible. Here, a catalyst-free tandem Zn-B exchange/oxidation enables near-quantitative conversion of CCTP-derived poly(ethylene-co-α-olefin) polymeryl-Zn intermediates into AA-type α,ω-dihydroxy tPOs with >95% difunctional ratios while preserving industrially relevant microstructures and allowing scale-up to ∼60 g per batch. These tPOs and their corresponding diester tPOs undergo polycondensation to afford alternating OBCs with controlled block lengths and tunable compositions. An architecture-controlled comparison with corresponding random analogs further shows that, although the overall composition primarily determines the total crystallinity, the alternating sequence leads to a more homogeneous nanoscale physical network, lower viscoelastic dissipation, more effective strain hardening, and improved cyclic stability with reduced stress relaxation. These results demonstrate that the AA-type telechelic platform not only expands telechelic polyolefin chemistry but also enables sequence-programmable polyolefin architectures with distinct and practically meaningful performance advantages, establishing sequence control as a powerful design lever for recyclable multiblock polyolefin materials.