Improved Flame-Retardant and Ceramifiable Properties of EVA Composites by Combination of Ammonium Polyphosphate and Aluminum Hydroxide

Abstract

Ceramifiable flame-retardant ethylene-vinyl acetate (EVA) copolymer composites for wire and cable sheathing materials were prepared through melt compounding with ammonium polyphosphate (APP), aluminum hydroxide (ATH) and fluorophlogopite mica as the addition agents. The effects of ammonium polyphosphate, alumina trihydrate, and APP/ATH hybrid on the flame retardant, as well as on the thermal and ceramifiable properties of EVA composites, were investigated. The results demonstrated that the composites with the ratio of APP:ATH = 1:1 displayed the best flame retardancy and the greatest char residues among the various EVA composites. The tensile strength of the composites was 6.8 MPa, and the residue strength sintered at 1000 °C reached 5.2 MPa. The effect of sintering temperature on the ceramifiable properties, microstructures, and crystalline phases of the sintered specimen was subsequently investigated through X-ray diffraction, Fourier transform infrared, and scanning electron microscopy. The XRD and FTIR results demonstrated that the crystal structure of mica was disintegrated, while magnesium orthophosphate (Mg3(PO4)2) was simultaneously produced at an elevated temperature, indicating that the ceramization of EVA composites had occurred. The SEM results demonstrated that a more continuous and compact microstructure was produced with the rise in the sintering temperature. This contributed to the flexural strength improvement of the ceramics.

Basalt Fiber Modified Ethylene Vinyl Acetate/Magnesium Hydroxide Composites with Balanced Flame Retardancy and Improved Mechanical Properties

“…Therefore, it is necessary to improve the flame retardancy. Flame retardancy can be achieved by adding flame retardants, e.g., aluminum trihydroxide (ATH) [ 3 ], layered double hydroxides (LDHs) [ 4 ], magnesium hydroxide (MH) [ 5 ], etc., among which MH is an environment-friendly flame retardant because of its decomposition temperature (about 340 °C, being higher than that of aluminum hydroxide), smoke suppressibility, non-toxicity, and wide use in halogen-free polymer materials. However, due to its high interface energy and strong hydrophilicity, the compatibility between MH and polymer matrix is poor, and the mechanical properties of EVA are decreased in accordance with the addition of MH [ 6 , 7 ].…”

Influence of irradiation crosslinking on the flame‐retardant properties of polyolefin blends

“…It should be noted that the PHRR value of SM7 was 407.6 kW/m 2 , which was higher than that of SM6 (312.6 kW/m 2 ). This result can be attributed to some antagonistic influences that occurred between the flame retardants of ultraCarb and magnesium hydroxide, and it increased the PHRR value of the blend . SM6 exhibited the lowest PHRR, which is indicative of the best flame retardancy in the second group.…”

“…With an increase in the irradiation dose, the Eb values slightly decreased for SM10, but the values increased for other compounds. The compounds were considered to meet the property requirements of sheathing used for wire and cable applications …”

Ammonium Polyphosphate with High Specific Surface Area by Assembling Zeolite Imidazole Framework in EVA Resin: Significant Mechanical Properties, Migration Resistance, and Flame Retardancy

“…Among the components of the hybrid IFR system, phosphor-containing flame retardants such as ammonium polyphosphate (APP) and its derivatives are the most widely used acid source [8][9][10]. However, the low compatibility between APP and polymer materials resulted in the emigration of APP and limited its flame retardancy especially in some extreme environments [11,12]. Therefore, it is necessary to develop a highly efficient IFR system, contributing to the better compatibility and flame-retardant efficiency when used in EVA composites.…”