Malleability and reprocessability of cross-linked polymers can be achieved via exchange reactions of the boronic ester crosslinking. Herein, we report a facile strategy to fabricate and modulate vitrimers by introducing intermolecular boron-nitrogen coordinated boronic ester crosslinking. Using a one-pot reaction, a series of boronic ester vitrimers based on polybutyl acrylate (PBA) was synthesized. The nitrogen containing monomer dimethylaminoethyl methacrylate (DMAEMA) was successfully copolymerized in the backbone to generate intermolecular boron-nitrogen (B–N) coordination. The presence of B–N coordination increases intermolecular interactions, leading to a denser crosslinked network structure and an elevated glass transition temperature. With the formation of B–N coordination, PBA-xB-yN samples at the same crosslinking density exhibit higher elongation at break and tensile strength. These samples dissipate more energy at the same strain and show a more pronounced strain rate dependency, highlighting the sacrificial role of the B–N coordination bonds. Stress relaxation experiments reveal that the intermolecular B–N coordination promotes faster relaxation of PBA-xB-yN compared to PBA-xB due to accelerated exchange dynamics of boronic ester. Mechanical reinforcement after recycling is observed in PBA-1B–2N, indicating that structural optimization of chemical and physical crosslinking occurs during thermal reprocessing. This study will provide a new strategy to fabricate boronic ester based vitrimeric materials with mechanical reinforcement and toughness enhancement.

中文翻译：

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通过分子间硼氮配位增强基于硼酸酯的玻璃体的机械性能


交联聚合物的延展性和可再加工性可以通过硼酸酯交联的交换反应来实现。在此，我们报告了一种通过引入分子间硼-氮配位硼酸酯交联来制造和调节 vitrimer 的简便策略。采用一锅反应，合成了一系列基于聚丙烯酸丁酯（PBA）的硼酸酯三聚体。含氮单体甲基丙烯酸二甲氨基乙酯（DMAEMA）在主链上成功共聚，产生分子间硼氮（B-N）配位。 B-N配位的存在增加了分子间相互作用，导致更致密的交联网络结构和更高的玻璃化转变温度。随着B-N配位的形成，相同交联密度的PBA-xB-yN样品表现出更高的断裂伸长率和拉伸强度。这些样品在相同应变下耗散更多能量，并表现出更明显的应变率依赖性，凸显了 B-N 配位键的牺牲作用。应力松弛实验表明，由于硼酸酯交换动力学加速，分子间 B-N 配位促进 PBA-xB-yN 比 PBA-xB 更快松弛。在 PBA-1B-2N 中观察到回收后的机械增强，表明在热再加工过程中发生了化学和物理交联的结构优化。这项研究将为制造具有机械增强和韧性增强的硼酸酯基玻璃材料提供新的策略。