Highly Tough Biobased Polyamides with Strong Adhesive and Stable Fluorescent Properties

With concerns about environmental pollution and the depletion of fossil resources, it is essential to adopt strategies to provide multifunctional materials by utilizing abundant and sustainable feedstocks. However, developing biobased polymeric materials with properties comparable to petroleum-based counterparts remains a great challenge. In this work, a series of polyamides were synthesized from plant oil-based E-octadec-9-enedioic acid monomer (C18) and diethylenetriamine via a facile one-pot approach, incorporating both dynamic hydrogen bonds and permanent covalent cross-links. By adjustment of the molar ratio of C18, the resulting polyamide (PA1.2) presents remarkable mechanical properties, including a high tensile strength of 30.3 MPa and an elongation at break of 611.8%. Moreover, the combination of reversible H-bonds and flexible long aliphatic chains endows elasticity and reprocessability to the thermosetting polyamides. The significant H-bond interactions, along with multipolar functional groups, also contribute to the polyamides’ strong adhesion to a variety of substrates, such as steel, wood, and other materials. These structural characteristics synergistically enhance the adhesion performance, with the polyamide adhesive achieving a robust adhesion strength of 14.28 MPa and excellent temperature adaptability. Notably, all of the obtained polymers exhibit unexpected fluorescence in the absence of conventional chromophores, presenting potential applications in fluorescent anticounterfeiting. Thus, this work not only offers a strategy for designing multifunctional polyamides but also provides insights into the use of biomass resources in anticounterfeiting technologies.