We report the mechanical performance and chemical recycling advantages of implementing alkyl-substituted poly(ε-caprolactones) (PCLs) as soft segments in thermoplastic poly(urethane-urea) (TPUU) materials. Poly(4-methylcaprolactone) (P4MCL) and poly(4-propylcaprolactone) (P4PrCL) were prepared, reacted with isophorone diisocyanate, and chain-extended with water to form TPUUs. The resulting materials’ tensile properties were similar or superior to a commercially available polyester thermoplastic poly(urethane) and had superior elastic recovery properties compared to a PCL analogue due to the noncrystalline nature of P4MCL and P4PrCL. Additionally, monomers were recovered from the TPUU materials in high yields via ring-closing depolymerization using a reactive distillation approach at an elevated temperature and a reduced pressure (240–260 °C, 25–140 mTorr) with zinc chloride (ZnCl₂) as the catalyst. The thermodynamics of polymerization were estimated using Van’t Hoff analyses for 4MCL and 4PrCL; these results indicated that the propyl group in 4PrCL results in a lower practical ceiling temperature (T_c) for P4PrCL.

中文翻译：

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烷基取代的聚己内酯聚氨基甲酸酯脲作为机械竞争力和化学可回收材料


我们报道了在热塑性聚氨基甲酸乙酯 （TPUU） 材料中将烷基取代的聚（ε-己丽糖酮）（PCL） 作为软链段实施的机械性能和化学回收优势。制备聚（4-甲基己内酯）（P4MCL）和聚（4-丙基己内酯）（P4PrCL），与异佛尔酮二异氰酸酯反应，并用水扩链生成 TPUUs。所得材料的拉伸性能与市售的聚酯热塑性聚（氨基甲酸酯）相似或优于市售聚酯热塑性聚（氨基甲酸酯），并且由于 P4MCL 和 P4PrCL 的非结晶性质，与 PCL 类似物相比具有优异的弹性恢复性能。此外，在高温和减压 （240–260 °C， 25–140 mTorr），氯化锌 （ZnCl₂） 作为催化剂。使用 4MCL 和 4PrCL 的 Van't Hoff 分析估计聚合的热力学;这些结果表明，4PrCL 中的丙基导致 P4PrCL 的实际天花板温度 （T_c） 较低。