Surface Functionalization of Black Phosphorus via Amine Compounds and Its Impacts on the Flame Retardancy and Thermal Decomposition Behaviors of Epoxy Resin

Abstract

Recently, lots of effort has been placed into stabilizing black phosphorus (BP) in the air to improve its compatibility with polymers. Herein, BP was chemically functionalized by aliphatic amine (DETA), aromatic amine (PPDA) and cyclamine (Pid) via a nucleophilic substitution reaction, aiming to develop an intensively reactive BP flame retardant for epoxy resin (EP). The -NH2 group on BP-DETA, BP-PPDA and BP-Pid reacted with the epoxide group at different temperatures. The lowest temperature was about 150 °C for BP-DETA. The impacts of three BP-NH2 were compared on the flame retardancy and thermal decomposition of EP. At 5 wt% loading, EP/BP-NH2 all passed UL 94 V 0 rating. The limiting oxygen index (LOI) of EP/BP-PPDA was as high as 32.3%. The heat release rate (HRR) of EP/BP-DETA greatly decreased by 46% and char residue increased by 73.8%, whereas HRR of EP/BP-Pid decreased by 11.5% and char residue increased by 50.8%, compared with EP. Average effective heat of combustion (av-EHC) of EP/BP-Pid was lower than that of EP/BP-DETA and EP/BP-PPDA. In view of the flame-retardant mechanism, BP nanosheets functionalized with aliphatic amine and aromatic amine played a dominant role in the condensed phase, while BP functionalized with cyclamine was more effective in the gas phase.

Excellent flame retardancy and air stability through surface coordination of few‐layer black phosphorus with TiL4 in epoxy resin

“…In addition, the fire risk of EP nanocomposites is also evaluated by the fire growth rate (FIGRA) 11,23,33 . The formula of FIGRA is expressed as follows: On the basis of Table 2 and Formula (1), the FIGRA of EP and its composites was calculated and listed in Table S2.…”

“…Compared with PHRR of EP/TiL 4 @BP 1.5, however, that of EP/BP 1.5 was markedly bigger, In addition, the fire risk of EP nanocomposites is also evaluated by the fire growth rate (FIGRA). 11,23,33 The formula of FIGRA is expressed as follows:…”

“…With the incorporation of 5 wt% fillers into EP, EP/BP‐NH 2 all can pass the UL‐94 V‐0 rating, and the limiting oxygen index (LOI) value of EP/BP‐PPDA is high as 32.30%. The results and analysis show that BP‐Pid exhibits effective in the vapor phase flame‐retardant mechanism rather than playing a major role in the condense phase mechanism (BP‐DETA and BP‐PPDA) 33 . In addition, based on the found of negative charged BP, Qiu et al obtained a new hindered phenol‐modified BP (BP‐HPL) using the reaction of the negatived charged BP with a hindered phenol antioxidant.…”

“…9,32 In The results and analysis show that BP-Pid exhibits effective in the vapor phase flame-retardant mechanism rather than playing a major role in the condense phase mechanism (BP-DETA and BP-PPDA). 33 In addition, based on the found of negative charged BP, Qiu et al…”

One‐Pot Covalent Functionalization of 2D Black Phosphorus by Anionic Ring Opening Polymerization

“…[62] Amination of BP nanosheets via nucleophilic substitution followed by a reaction with epoxy resin resulted in novel nanocomposites through a multistep pathway. [65] The above-mentioned reactions, however, rely on a "grafting-to" approach through which the (macro)molecule is converted to a reactive reagent and then associated to create 2D platforms via different pathways. Functionalization of 2D nanomaterials using the "grafting-from" approach is a straightforward method to produce new materials, [66] in which polymerization of monomers is initiated from the surface of the 2D nanoplatform and continued by self-propagation.…”