Modified expandable graphite as an effective flame retardant for LLDPE/EVA composites filled with Mg(OH)₂/Al(OH)₃

Abstract

The flammability, thermal properties, and synergistic effects of modified expandable graphite (MEG) with magnesium hydroxide (MH) and aluminum hydroxide (ATH) on the linear low-density polyethylene/ethylene vinyl acetate (LLDPE/EVA) blends are investigated by Underwriters Laboratories-94 (UL-94) vertical combustion test, limiting oxygen index (LOI), thermogravimetric analysis (TGA), cone calorimeter test (CCT), and scanning electron microscopy (SEM). The results show that the MEG improves the flame-retardant efficiency of LLDPE/EVA blends. The addition of MEG apparently improves the LOI values and the UL-94 rating of LLDPE/EVA composites. The data obtained from the CCT show that the heat release rate (HRR), the total heat release (THR), and the gas production rate of composites with MEG decrease remarkably with increasing the content of MEG. When 10 phr of MEG is added, the char residues of LEMEG10 increase to 38.2% from 2.7% of LLDPE/EVA. The results of SEM and CCT present that MEG can improve the quality of char layers. The rate of char formation is enhanced also due to the existence of MEG, which plays an important role to improve the flame retardancy of the LLDPE/EVA composites.

A novel application of titanium suboxide to enhance the flame retardancy, thermal stability, and thermal and electrical conductivity of silicone rubber

“…This observation suggests that the incorporation of Ti 4 O 7 not only hinders the premature decomposition of the silicone rubber but also reduces its rate of mass loss. 25,26 An intriguing phenomenon is noted: while the thermal decomposition of pure silicone rubber exhibits a single decomposition phase, the addition of Ti 4 O 7 introduces two decomposition phases, particularly in the temperature range of 660–690°C, where a distinctive peak of thermal weight loss emerges. 27 This phenomenon is likely attributed to the presence of Ti 4 O 7 , which exhibits the capacity to absorb a substantial amount of gases released during the fracture of silicone rubber molecular chains, particularly in the intermediate and later phases of decomposition.…”

Phosphorylated avocado seed: A renewable biomaterial for preparing a flame retardant biofiller

“…Low-Density PolyEthylene (LDPE) and Ethylene Vinyl Acetate (EVA) blends are used in several applications, such as in the wire and cable industry, thanks to its good flexibility, low cost, and low toxicity, among others. 8 Many different systems have been used for improving the flame retardant properties of polymer composites, among which are some metallic hydroxides such as aluminum and magnesium hydroxide. 9,10 Clays have also been used, which act as a protective char layer on the polymer surface reducing the material dripping 11,12 ; Lately, however, studies are directed at the incorporation of environmentally friendly compounds, among which stand out, the incorporation of desoxyribonucleic acid (DNA) and ammonium polyphosphate, [13][14][15] which have shown that good flame retardant properties were obtained, thanks to the formation of a protective char layer.…”

“…On the other hand, many polymers with inherent low flame resistance properties, 7 could benefit by using this modified bio‐filler. Low‐Density PolyEthylene (LDPE) and Ethylene Vinyl Acetate (EVA) blends are used in several applications, such as in the wire and cable industry, thanks to its good flexibility, low cost, and low toxicity, among others 8 …”

Flame retardancy effect of phosphorus graphite nanoplatelets on ethylene‐vinyl acetate copolymer: Physical blending versus chemical modification

“…A reasonable yet well‐accepted approach to solve this problem is to incorporate flame‐retardant additives to improve flame retardancy and anti‐dripping properties of EVA 8,12,13 . In recent years, a wide variety of flame retardant additives have been examined in EVA among which are mineral components (zinc borate, 14–18 magnesium hydroxide, 16,19,20 aluminium hydroxide 16,21,22 ), phosphorus‐based materials (red phosphorus, 23,24 ammonium polyphosphate (APP), 7,22,25–27 nitrogen‐based systems (melamine 28,29 ), and carbon‐based flame retardants (expandable graphite [EG], 30–33 graphene nanoplatelets, 34–36 and graphene oxide 30,37 ). Overall, it has been demonstrated that carbon‐based materials such as graphene can change the pyrolysis pathway, dripping, and thermal conductivity in polymer systems 38 .…”

“…Overall, it has been demonstrated that carbon‐based materials such as graphene can change the pyrolysis pathway, dripping, and thermal conductivity in polymer systems 38 . On the other hand, FR additives appear effective only when used at high loading, which is unavoidably detrimental to the mechanical properties of the polymers 29–31 …”