Synergistic effect between phosphorus tailings and aluminum hypophosphite in flame‐retardant thermoplastic polyurethane composites

Abstract

The massive accumulation of phosphorus tailings (PT) not only occupies land resources and also causes great threat to ecological environment and human security.It is of great significance to explore the resource utilization of PT in some fields. Herein, aluminum hypophosphite (AHP) and PT are blended together to enhance the flame retardancy of thermoplastic polyurethane (TPU) composites, and the synergistic effects between AHP and PT are investigated systematically. Cone calorimeter test (CCT) results indicate that the peak heat release rate (PHRR) and total heat release (THR) of the samples containing 25 wt% AHP are decreased by 89% and 68%, respectively, and the total smoke release (TSR) show a reduction of 58.8%, in comparison with those of neat TPU. For the sample TPU/22.5AHP/2.5PT, the PHRR, THR, and TSR are decreased by 91.2%, 70%, and 63%, respectively. Scanning electron microscopy (SEM) analysis results demonstrate that the addition of PT can facilitate the generation of dense and compact char layers, preventing the release of heat and smoke effectively. All the abovementioned results indicate that the synergistic effects are existed between AHP and PT for enhancing the fire safety of TPU composites, which can provide a new way for the utilization of PT. KEYWORDS aluminum hypophosphite, flame retardant, phosphorus tailings, synergistic effect

Thermoplastic polyurethane composites based on aluminum hypophosphite/modified iron tailings system with outstanding fire performance

“…27 AHP is usually combined with other flame retardants to obtain better flame retardant performance. [28][29][30][31] Zhou et al 32 added AHP and phosphate tailings (PT) into TPU to enhance fire performance of TPU composites. The results confirmed that the peak heat release rate (PHRR), total heat release rate (THRR) and peak smoke production rate (P-SPR) of TPU/AHP22.5/PT2.5 were 91.2%, 69.9%, and 50.9% decreased compared with those of pure TPU, indicating excellent fire retarding performance of AHP/PT synergistic system.…”

Flame Retarded Rigid Polyurethane Foams Composites Modified by Aluminum Diethylphosphinate and Expanded Graphite

“…Metal hypophosphate, as a novel flame retardant, is widely used in enhancing fire performance of polymers, including polylactides, thermoplastic polyurethane, and polyamide (Tang et al, 2012;Zhou et al, 2019;Pan et al, 2020). Tang et al report flame retarded polyurethane foam composites based on aluminum diethylphosphinate (ADP), in which 30 php ADP loading makes RPUF composites possess LOI of 23.0 vol% .…”

Transparent, flame‐retarded, self‐healable, mechanically strong polyurethane elastomers: Enabled by the synthesis of phosphorus/nitrogen‐containing oxime chain‐extender

“…To the contrary, non-burning hetero atoms, such as N-, P-, S-, Si-, and B-containing derivative compounds can efficiently reduce flammability when incorporated into the polymer main chain or copolymerized. [19][20][21][22][23][24] Besides, a series of important halogen-free flame retardant systems are applied in the flame retardant of PU, including ammonium polyphosphate (APP), 25 aluminum hypophosphite (AHP), 26 melamine pyrophosphate (MPP), 27 expandable graphite (EG), 28 2D materials [29][30] et al Thereinto, phosphorus plays the important role in halogen-free flame retardancy due to its chemical versatility, multiple FR mechanisms, and high effectivity already at lower loadings.…”