(CF3SO3)3Er-decorated black phosphorene for robust ambient stability and excellent flame retardancy in epoxy resin

Abstract

Owing to its intrinsic structure, thermal stability and dimension effects, black phosphorene (BP) has great potential in manufacturing advanced-performance polymer composites. However, the shortcoming of instability and re-agglomeration enables great challenges toward its application. Herein, a lanthanide metal ligand ((CF3SO3)3Er) has been employed to decorate few-layer BP nanosheets. By means of density functional theory (DFT), there is a high adsorption energy of −1.49 eV in the system, which confirms a powerful adsorbing effect is existed between BP and (CF3SO3)3Er. Due to the charge transfer from BP to (CF3SO3)3Er molecule, the lone-pair electrons of BP are passivated, thereby the decorated BP (Er-BP) exhibits robust stability in ambient conditions and common solvents. Whereafter, the Er-BP is loading into epoxy resin (EP) to manufacture EP-based composites. The Er-BP can not only effectively enhance the dispersion of BP in EP substrate, but also catalyze the curing process of EP nanocomposites. When the amount of Er-BP in epoxy is 3.0 wt%, the residual char content is clearly improved by 75.42%, which is attributed to the coadjutant catalytic charring function between BP and (CF3SO3)3Er. EP/Er-BP 3.0 sample can meet the requirement of UL-94 V-0 testing, and the limiting oxygen index (LOI) value is improved from 24.7% to 30.3%. Meanwhile, there is a 61.37% reduction in the peak heat release rate (PHRR) and a 36.68% decrease in the total heat release (THR). The smoke production rate (SPR) and total smoke production (TSP) are also decreased by 62.90% and 55.94%, respectively. Particularly, the amount of CO released per second (COP) is dramatically reduced by 74.24%, implying that the heat and smoke release has been significantly suppressed due to the production of protective char layer.