摘要
Recent advances reported polyurethanes with hard-segment main chains and soft-segment side chains. However, fundamental understanding of their aggregation structures, deformation mechanisms, and potential applications remained limited. Besides, existing designs were confined to polyether or zwitterion side chains, with polyester-based variants unexplored. Herein, we synthesized a kind of novel comb polyurethanes with polycaprolactone (PCL) sidechains attached to hard backbone (SPPU). Comprehensive characterizations revealed distinct aggregation structures in SPPU compared to linear PCL-based polyurethanes (PPUs) from different aspects. Strain-dependent analysis was first applied to uncover the distinctive deformation mechanism of SPPUs in this study. While PPUs’ deformation was mainly driven by soft-segment elongation, low hard-segment SPPUs underwent whole-chain slippage-dominated deformation (enhancing chain mobility) and high hard-segment SPPUs demonstrated hard-segment elongation-based deformation (reinforcing rigidity). SPPUs exhibited enhanced room-temperature loss modulus and absolute damping capacity compared to PPU. Low hard-segment SPPU exhibited significantly higher loss factor and displayed superior impact protection performance. High hard-segment SPPUs exhibited substantially increased modulus than linear PUs. SPPUs also exhibited improved acid/alkali corrosion-resistance, extending the service life in corrosive environments. Superior melt flowability of SPPUs at high temperature highlighted the topological design in improving processability. The synergy of tunable stiffness, optimized damping and durability positioned SPPUs as transformative materials for optimization of conventional linear PCL-based PUs. This work afforded the first polyester-based comb PU system and crucial molecular design insights for advanced high-performance polyurethane materials.
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