Low-Temperature Resistant and Biocompatible Hot-Melt Adhesives Enabled by Triblock Thermoplastic Polyester Elastomers

The state-of-art commercial polymeric adhesives are mainly petroleum-based, non-biodegradable and not tolerant of low temperature, severely limiting their applications in extremely cold regions. Current research efforts focus on development of sustainable and biodegradable polyester-based adhesives. However, nearly all the reported polyester-based adhesives were used at room temperature, and the innovative functional polyester-based adhesives with low-temperature-resistance are very rare. Herein, we rationally designed and synthesized triblock thermoplastic polyester elastomers, poly(1,4-dioxan-2-one)-b-poly(γ-methyl-ε-caprolactone)-b-poly(1,4-dioxan-2-one) (PPDO-b-PMCL-b-PPDO), serving as high-performance biodegradable hot-melt adhesive with excellent low-temperature-resistance. The mechanical and viscoelastic properties of polyester-based adhesives could be readily modulated by varying molecular weight and fraction of hard/soft blocks via controlled ring-opening polymerization. PPDO-b-PMCL-b-PPDO with appropriate volume fraction of hard blocks exhibited strong adhesion to a range of substrates (with a bonding strength high up to 5.0 MPa) both at room temperature and even at cryogenic temperature (-196°C). The polyester elastomer-based adhesives outperformed some common commercial petroleum-based hot-melt adhesives, showing their great potential in the specific scenarios like polar-region exploration.