Flame resistance and foaming properties of NBR compounds with halogen‐free flame retardants

Abstract

Acrylonitrile butadiene rubber (NBR) foams compounded with various halogen-free flame retardants were prepared. The influence of nonhalogen flame retardants on the flame resistance and foaming properties of the NBR compounds were investigated. The foaming properties (expandability 980%-1050%, closedcell structure) of NBR compounds with expandable graphite (EG) and ammonium polyphosphate (APP) flame retardants were similar to the NBR base compounds which contained primarily aluminum hydroxide (ATH). The heat release capacity (HRC) ranged from 10 to 74 J/g-K, the average heat release rate (A-HRR) ranged from 8 to 60 kW/m 2 , and the total heat release (THR) ranged from 2.6 to 7.3 MJ/m 2 for the nonhalogenated NBR foams with closed-cell structure and were significantly decreased upon increasing the amounts of flame retardants. This reduction is attributed to the hard char formation and production of water from the interaction with ATH. The limiting oxygen index (LOI) and time to ignition (TTI) show opposite results. The smoke density (0.050-0.037) of the NBR foams with EG flame retardant was decreased when compared to the NBR foam (0.107). The EG flame retardant was more effective than the phosphorus/nitrogen flame retardants in reducing the HRR and smoke density. The use of both ATH and EG is very effective in improving flame resistance.

Preparation of novel hyperbranched flame‐retardant polymer and its application into natural rubber systems

“…ATH were identified for use, and zinc borate was considered as synergists with ATH 4. Expandable graphite was identified for use in other elastomers and had potential for polyisoprene 5. Alternative nanoscale fire retardants such as montmorillonite clay6 and multiwalled carbon nanotubes7 were reported typically as a secondary additive to hydrated fillers.…”

“…4 Expandable graphite was identified for use in other elastomers and had potential for polyisoprene. 5 Alternative nanoscale fire retardants such as montmorillonite clay 6 and multiwalled carbon nanotubes 7 were reported typically as a secondary additive to hydrated fillers. Other potential approaches were identified including the use of phosphorus-and nitrogenbased additives, such as phosphorus and pentaerythritol (PER), as intumescent char formers, and with zeolites as char catalysts.…”

Combination of Phosphorous Flame Retardants and Aluminum Trihydrate in Multicomponent EPDM Composites

“…Combinations of ATH and APP aim for the thermally stable P-Al-O surface coating to improve surface protection [26]. Previous studies described the synergistic interplay of aluminum hydroxide and aluminum hypophosphite with APP [27][28][29], and nanoparticles [1,30,31] in elastomers.…”

Effects of montmorillonite on the electron beam irradiated alumina trihydrate added polyethylene and ethylene vinyl acetate nanocomposite

“…However, both LDPE and EVA possess flammable characteristic, which has limited their usage in wire and cable applications. It is commonly known that the fire risk of polymers can be minimized by incorporation of flame‐retardants into the polymer matrix [ 4, 5]. The flame‐retardancy of LDPE‐EVA blend is usually improved or modified by adding suitable flame‐retardants such as alumina trihydrate (ATH), zinc borate, etc [ 5, 6].…”

“…It is commonly known that the fire risk of polymers can be minimized by incorporation of flame‐retardants into the polymer matrix [ 4, 5]. The flame‐retardancy of LDPE‐EVA blend is usually improved or modified by adding suitable flame‐retardants such as alumina trihydrate (ATH), zinc borate, etc [ 5, 6]. The addition of flame‐retardants into LDPE‐EVA blends is crucial to fulfill the fire resistance as required by the strict building standards [ 7].…”