High‐Strength, Flame‐Retardant, UV‐Resistant Polyurethane Elastomers Realized by Synergizing Nitrogen‐Phosphorus‐Containing Ligands and Cerium Oxide Nanoparticles

ABSTRACT High fire safety, aging resistance, and excellent mechanical properties are particularly important for polyurethane elastomers in electronic encapsulation and membrane materials. Here, we synthesized a polyurethane elastomer material with enhanced mechanical properties, as well as better fire safety and UV aging resistance through the design of nitrogen and phosphorus‐containing elemental chain extenders (BFPP and AHMT) and the incorporation of cerium oxide nanoparticles. Sample APU‐BFPP‐4 spiked with 1.25% AHMT, 2.5% BHPP, and 5% cerium oxide nanoparticles can pass the UL‐94 V‐0 rating and the LOI increases to 27.5%. The PHRR and THR of the APU‐BFPP composites were lower than those of PU by 6.42% and 14.56%, respectively. Meanwhile, the addition of cerium oxide nanoparticles can effectively improve the UV shielding and mechanical properties of polyurethanes; the APU‐BFPP composites can achieve 100% UV shielding in the full UV band, and the mechanical properties can reach 30 MPa. In order to investigate the flame‐retardant mechanism, the condensed phase and gas phases of PU elastomer combustion have been analyzed; the results showed that the flame‐retardant mode of the APU‐BFPP composites was mainly dominated by the trapping of fuel free radicals and the carbon layer blocking effect. Compared with the flame‐retardant PU composites that have been reported, APU‐BFPP composites have achieved a better balance between efficient flame retardancy, UV protection properties, and good mechanical properties, which makes it perform well in electronic encapsulation and membrane materials.