Daoxin Wu,Shuyao Li,Jingkun Sun,Yang Qiu,Zhaoyang Wu,Wenzhao Liu
A novel ZIF-8/carboxylated polyurethane 3D photonic crystal sensor is developed for putrescine and cadaverine detection. • Dual sensing mechanism: ZIF-8 enables size-selective adsorption and refractive index modulation, while PU provides carboxyl-amine acid-base swelling. • The optimal sensor (n BDO :n DMBA = 3:7) achieves a low detection limit of 0.86 ppm for putrescine and high selectivity over common VOCs. • Synergistic signal amplification yields a maximum reflection peak shift of 27.02 nm at 100 ppm. Rapid on-site detection of biogenic amines (e.g., putrescine and cadaverine) is critical for food freshness monitoring. Herein, we report a three-dimensional photonic crystal (3DPC) sensor composed of ZIF-8 nanoparticles and carboxyl-functionalized polyurethane (PU). The PU matrix, with tunable carboxyl content via DMBA/BDO ratio, enables acid-base induced swelling upon exposure to amine vapors, while ZIF-8 provides size-selective enrichment and refractive index modulation. The sensor with an optimal n BDO :n DMBA molar ratio of 3:7 exhibits a low detection limit of 0.86 ppm for putrescine, a sensitivity of 0.2384 nm/ppm, and excellent selectivity over common VOCs. The synergistic dual-mechanism (swelling + refractive index change) yields a maximum reflection peak shift of 27.02 nm at 100 ppm. Moreover, the sensor shows moderate response time (2.5 min) and good long-term stability (35 days). This work provides a new strategy for integrating MOF adsorption and polymer swelling into a visual sensing platform for biogenic amines.
Impurity sulfate produced in upstream process of nylon 54 salt (cadaverine succinate) are significantly impacting the product quality. In the present study, we elucidated the mechanism underlying the crystallization of the nylon 54 salt; using sulfate ions as the only inorganic impurity before crystallized nylon 54 salt, we revealed the principles underlying their impact. Specifically, sulfate ions profoundly affect the thermodynamics and kinetics of nylon 54 salt crystallization. The solubility of the monomer salt decreased. At 288.15 K, the solid-liquid interfacial energy, critical nucleation radius, and Gibbs free energy increased 0.104 mJ . m −2 , 2.890 × 10 −10 m, and 9.668 × 10 −22 J respectively. The increased nucleation barrier further hinders the crystallization of nylon 54 salt. Molecular dynamics simulations reveal that sulfate impurities reduce molecular diffusion, enhance hydrogen bond formation, increase intermolecular and overall interaction energy. Thus, our study provides valuable insights into the one-step separation of bio-based cadaverine and succinic acid in a coproduction system.
危险品化学品经营许可证（带存储）