Surface Modification of Ammonium Polyphosphate for Enhancing Flame-Retardant Properties of Thermoplastic Polyurethane

Abstract

Currently, the development of efficient and environmentally friendly flame-retardant thermoplastic polyurethane (TPU) composite materials has caused extensive research. Ammonium polyphosphate (APP) is used as a general intumescent flame retardant to improve the flame retardancy of TPU. In this paper, we developed a functionalized APP flame retardant (APP-Cu@PDA). Adding only 5 wt% of APP-Cu@PDA into TPU can significantly improve the flame-retardant’s performance of the composite material, reflected by a high LOI value of 28% with a UL-94 test of V-0 rating. Compared with pure TPU, the peak heat release rate, total heat release, peak smoke release rate, and total smoke release were reduced by 82%, 25%, 50%, and 29%, respectively. The improvements on the flame-retardant properties of the TPU/5%APP-Cu@PDA composites were due to the following explanations: Cu2+-chelated PDA has a certain catalytic effect on the carbonization process, which can promote the formation of complete carbon layers and hinder the transfer of heat and oxygen. In addition, after adding 5% APP-Cu@PDA, the tensile strength and elongation at the break of TPU composites did not decrease significantly. In summary, we developed a new flame-retardant APP-Cu@PDA, which has better flame-retardant properties than many reported TPU composites, and its preparation process is simple and environmentally friendly. This process can be applied to the industrial production of flame retardants in the future.

Facile preparation of a hydrophobic intumescent flame retardant toward simultaneously enhanced flame retardancy and smoke suppression of thermoplastic polyurethane

“…For TPU/4APP, the peaks at 1540 cm −1 , 818 cm −1 and 744 cm −1 are associated with CC, the aromatic ring and C–N, respectively. 52–54 Compared to TPU/4APP, the char residues of TPU/4HIFR display several new peaks at 3437 cm −1 , 1430 cm −1 , 1187 cm −1 , 1082 cm −1 and 505 cm −1 , corresponding to N–H, C–H, PO, P–O–P and OP–O, respectively. 5,55–58 The absorption bands for P–O–P and OP–O indicate the existence of the phosphate ester fragment and pyrophosphate fragment in the char residues, and then contribute to the formation of high-quality char layers.…”

“…For TPU/4APP, the peaks at 1540 cm À1 , 818 cm À1 and 744 cm À1 are associated with CQC, the aromatic ring and C-N, respectively. [52][53][54] Compared Fig. 13 The flame-retardant mechanism of TPU/HIFR.…”

Monitoring Ammonium Polyphosphate (APP) Biodegradation by Acinetobacter nosocomialis D-3 Using DAPI

“…While HFRs present significant environmental and health hazards due to their release of toxic smoke and gaseous hydrogen halides during combustion, HFFRs have emerged as rapid alternatives, characterized by their efficiency, non-toxicity, and environmental compatibility [ 2 , 3 ]. Ammonium polyphosphate (APP), a pivotal component of HFFRs, has garnered substantial attention for its notable biological safety profile and cost-effectiveness [ 4 ]. Within many formulations of APP-based flame retardants, APP assumes a primary role, serving as both an acid and gas source, thereby determining the formulation’s fire prevention efficacy based on APP quality and abundance [ 5 ].…”

Characterization and Flame-Retardant Properties of Cobalt-Coordinated Cyclic Phosphonitrile in Thermoplastic Polyurethane Composites

“…Thermoplastic polyurethane (TPU), also referred to as polyurethane rubber, is classified under the thermoplastic elastomer (TPE) category [1][2][3]. Its notable characteristics include elasticity, wear resistance, chemical stability, and plasticity, which have led to its extensive utilization in industries such as aerospace, automotive, and marine [4][5][6]. However, TPU is an extremely flammable material, The molten droplets generated during the combustion process not only spread the fire but also release a significant amount of toxic and harmful gases, such as CO, HCN, NOx, etc.…”