Sugar-Functionalized Polyethylenes with High Adhesion and Triggerable Degradability.

Designing renewable sugar-based monomers provides an attractive way to access high-performance polymers with novel properties. Herein, we report the synthesis of sugar-functionalized polyethylenes via the catalytic copolymerization of ethylene with a newly designed cyclobutene-fused tri-O-benzyl d-glucal (CBG) comonomer. The copolymerization yields polar polyethylenes with tunable CBG content (up to 8.3 mol %). Notably, the benzyl protecting groups can be easily removed via photocatalytic mesolytic cleavage to afford unprotected sugar-functionalized polyethylenes. The free hydroxyl groups endow the polyethylene materials with excellent adhesive strength on copper (16.84 MPa) and wood (15.30 MPa). These free hydroxyl groups can also be used to graft polylactic acid side chains, yielding an effective compatibilizer for HDPE/PLA blends. Furthermore, the incorporated cyclobutene-fused d-glucal units are mechanoresponsive and undergo selective cycloreversion to introduce acid-sensitive enol ether units into the polymer backbone. Therefore, these sugar-functionalized polyethylenes exhibit an ideal combination of a high adhesive performance and triggerable hydrolytic degradability.