Gao Chang, Poon Kam C, Concilio Matilde, Zinn Thomas, Gregory Georgina L, Williams Charlotte K
Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom.
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, United Kingdom.
Adv Mater. 2025 Jul;37(27):e2416674. doi: 10.1002/adma.202416674. Epub 2025 Apr 16.
Polyester thermoplastic elastomers are promising sustainable materials but their mechanical properties need improvement, in particular, attempts to increase strength often result in compromised elasticity. Strong and tough elastomers are known but require complex polymer formulations together with control over cross-linking or crystallinity, both of which challenge recycling. Here, the introduction of transient strain-stiffening approaches into fully amorphous structures show both strengthening and toughening of elastomers while conserving recyclability. The new amorphous block polyester elastomers are prepared by controlled polymerization methods using commercial monomers. The block polymers comprise a central poly(ɛ-caprolactone-co-ɛ-decalactone) block flanked by poly(cyclohexene oxide-alt-phthalate) blocks. Elastomer thermomechanical properties are tuned by varying ratios of ɛ-caprolactone to ɛ-decalactone within the mid-block to access materials with excellent mechanical properties. The best elastomers feature 30-50 wt.% polycaprolactone and exhibit tensile strengths up to 40 MPa, elongations at break above 2000%, with excellent elastic recovery (>90%). These materials exhibit strain-induced crystallization and outperform current commercial elastomers, entering a new region of tensile mechanical property space. They have service temperature ranges from -60 to 140 °C and high temperature stability (≥300 °C), with wide thermal (re)processing windows. These new polyester elastomers also show high resistance to creep, humidity resistance, and excellent recyclability.
聚对苯二甲酸乙二酯热塑性弹性体是很有前景的可持续材料，但它们的机械性能需要改进，特别是，提高强度的尝试往往会导致弹性受损。已知有强度高且坚韧的弹性体，但需要复杂的聚合物配方以及对交联或结晶度的控制，而这两者都对回收利用构成挑战。在此，将瞬态应变强化方法引入完全无定形结构中，既显示出弹性体的强化又显示出增韧，同时保留了可回收性。新型无定形嵌段聚酯弹性体是使用商业单体通过受控聚合方法制备的。嵌段聚合物包含一个中心聚（ε-己内酯-共-ε-癸内酯）嵌段，两侧是聚（环己烯氧化物-交替-邻苯二甲酸酯）嵌段。通过改变中间嵌段中ε-己内酯与ε-癸内酯的比例来调节弹性体的热机械性能，以获得具有优异机械性能的材料。最佳的弹性体具有30-50 wt.%的聚己内酯，拉伸强度高达40 MPa，断裂伸长率超过2000%，具有优异的弹性回复率（>90%）。这些材料表现出应变诱导结晶，性能优于目前的商业弹性体，进入了拉伸机械性能空间的一个新区域。它们的使用温度范围为-60至140°C，具有高温稳定性（≥300°C），具有宽的热（再）加工窗口。这些新型聚酯弹性体还表现出高抗蠕变性、耐湿性和优异的可回收性。
