Thiele Sophia, Giffin Michael, Wendling Matthieu, Görl Daniel, Plummer Christopher J G, Frauenrath Holger
École Polytechnique Fédérale de Lausanne (EPFL), Institute of Materials 1015 Lausanne Switzerland
Org Chem Front. 2025 May 13. doi: 10.1039/d5qo00087d.
Benzenetricarboxamide (BTA) derivatives are versatile compounds widely employed as nucleating agents in commercial semicrystalline plastics and as supramolecular ligands in self-assembling telechelic polymer-based organogels, hydrogels, and bulk elastomers. However, their effectiveness as supramolecular modifiers is typically limited to low-molar-mass apolar polymers. Here, we report the supramolecular aggregation of a BTA-end-functionalized semicrystalline aliphatic polyester with a number-average molar mass several times its entanglement molar mass, blended with a matching low-molar-mass BTA additive. In these blends, the BTA end groups and additive co-assemble to form a new phase comprising a network of polymer-bridged nanofibrils. This network gives rise to a high-melt-strength rubbery regime that is absent from the pure telechelic polyester but extends to temperatures well above its melting point in the blends. Moreover, the nanofibrils prove to be highly efficient nucleating agents for crystallization of the polyester, significantly outperforming bulk additive precipitates. Our findings hence demonstrate that the co-assembly of polymer end groups with a low-molar-mass additive may facilitate supramolecular aggregate formation in polymer matrices where end-modification alone is insufficient, leading to materials with increased melt strength, crystallization rates, thermal dimensional stability, and valuable benefits for industrial applications.
苯三甲酰胺（BTA）衍生物是用途广泛的化合物，在商业半结晶塑料中广泛用作成核剂，在基于自组装遥爪聚合物的有机凝胶、水凝胶和本体弹性体中用作超分子配体。然而，它们作为超分子改性剂的有效性通常仅限于低摩尔质量的非极性聚合物。在此，我们报道了一种数均摩尔质量为其缠结摩尔质量数倍的BTA端基功能化半结晶脂肪族聚酯与匹配的低摩尔质量BTA添加剂共混后的超分子聚集。在这些共混物中，BTA端基和添加剂共同组装形成一个新相，该新相由聚合物桥接纳米纤维网络组成。这个网络产生了一种高熔体强度的橡胶态，纯遥爪聚酯中不存在这种状态，但在共混物中可延伸至远高于其熔点的温度。此外，纳米纤维被证明是聚酯结晶的高效成核剂，显著优于本体添加剂沉淀物。因此，我们的研究结果表明，聚合物端基与低摩尔质量添加剂的共组装可以促进在仅靠端基改性不足以形成超分子聚集体的聚合物基体中形成超分子聚集体，从而得到具有更高熔体强度、结晶速率、热尺寸稳定性的材料，并为工业应用带来宝贵的益处。
