Intrinsic flame retardant phosphonate-based vitrimers as a recyclable alternative for commodity polymers in composite materials
Intrinsic flame retardant phosphonate-based vitrimers as a recyclable alternative for commodity polymers in composite materials
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DOI：
10.1039/d0py00275e
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发表时间：
2020-08-14
影响因子：
4.6
通讯作者：
Wurm, Frederik R.
中科院分区：
文献类型：
--
作者：
Markwart, Jens C.;Battig, Alexander;Wurm, Frederik R.
交联纤维增强聚合物的回收是困难的。此外，由于它们通常基于易燃树脂，因此需要额外的添加剂。所谓的"玻璃体聚合物"开启了利用动态交联化学品进行回收、再加工和修复的可能性。迄今为止，基于玻璃体聚合物的复合材料仍然需要阻燃添加剂，例如有机磷酸酯。无添加剂的玻璃质聚合物复合材料尚未报道。本文以含共价键膦酸酯的乙烯基聚氨酯为阻燃单元，合成了一种本征阻燃的玻璃酸盐，并制备了玻璃纤维增强复合材料。我们研究了回收和阻燃性能，并将数据与无磷的玻璃化树脂和传统的环氧树脂（有和没有添加阻燃剂）进行了比较。我们的膦酸酯基玻璃化聚物在首次测试中证明，其阻燃效果与商用阻燃树脂相当。磷玻璃纤维复合材料的弯曲强度和弯曲模量与具有永久交联环氧树脂的玻璃纤维复合材料相当。总之，我们能够证明膦酸酯共价安装到vitrimers允许制备不需要阻燃添加剂的可回收和固有的阻燃复合材料。我们相信这一概念可以扩展到其他聚合物网络和添加剂，以产生可回收和可持续的高性能材料。
Recycling of crosslinked fiber-reinforced polymers is difficult. Moreover, as they are often based on flammable resins, additional additives are needed. So-called "vitrimers" open the possibility of recycling and reprocessing and repairing with dynamically crosslinked chemistries. To date, vitrimer-based composites still need flame retardant additives, such as organophosphates. An additive-free vitrimer composite has not been reported. Herein, we synthesized an intrinsic flame-retardant vitrimer, relying on vinylogous polyurethanes containing covalently installed phosphonates as flame-retardant units and prepared glass-fiber-reinforced composites. We studied recycling and flame retardant properties and compared the data to phosphorus-free vitrimers and conventional epoxy resins (with and without additive flame retardant). Our phosphonate-based vitrimer proved in first tests, a flame retardant effect comparable to commercial flame retardant resins. The bending strength and bending modulus for the phosphorus-vitrimer glass fiber composites were comparable to glass fiber composites with permanently cross-linked epoxies. In summary, we were able to prove that the covalent installation of phosphonates into vitrimers allows the preparation of recyclable and intrinsic flame retardant composites that do not need flame retardant additives. We believe this concept can be expanded to other polymer networks and additives to generate recyclable and sustainable high-performance materials.