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Flame retardant- Presentation

Flame retardant- Presentation - Flame Retardants Group...

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Unformatted text preview: Flame Retardants Group 4—April 8 th Danielle Keese Jeff Mueggenborg Esan Savannah Ha Nguyen Dangers of Fire (United States in 2002) ¡ Someone died in a fire every 3 hrs and someone was injured every 37 minutes ¡ 401,000 home fires ¡ Residential fires caused more than $6.1 billion in property damage What is a Flame Retardant? ¡ A chemical added to combustible materials to render them more resistant to ignition ¡ Minimizes the risk of fire starting ¡ Increases the safety of lives and property What is a Flame Retardant? ¡ 4 major family of Flame Retardant ¡ Provides for a safer material without compromising performance ¡ Flame retardants work to slow or stop the combustion cycle Combustion Cycle ¡ Flammable materials are decomposed to release energy in the form of heat and light ¡ Combustion of hydrocarbon: ¡ Examples of combustion: ¢ Phosphorus CH 3 PH 4 +4O 2 → CO 2 + 2H 2 O + H 3 PO 4 + ∆ H ¢ Methane Chloride CH 3 ClH 2 + 2O 2 → CO 2 + H 2 O + HCl + ∆ H H O H n nCO O H C spark y x ∆ + ′ + ⎯ ⎯ → ⎯ + 2 2 2 Polymeric Plastic Combustion ¡ The combustion reaction takes place in the vapor phase ¡ 3 phases of products of pyrolysis: ¢ Liquid ¢ Solid ¢ Vapor Flame Retardant Families Halogenated FRs Chlorinated ¡ Wider Temperature range for radical release ¡ Used most commonly as a paraffin additive Brominated ¡ Most common FR in production ¡ Five classifications, with over 75 compounds on the market ¡ High degree of control over release temperature Halogenated FRs ¡ Act in the Vapor phase ¡ Reduce the heat generated by flames, thereby inhibiting the formation of flammable gases ¡ Behave according to a “Free Radical Trap” theory H O H OH H Br O H HBr OH H HBr H Br Br R Br R n heat x n ∆ + → ⋅ + ⋅ ⋅ + → + ⋅ ∆ − → ⋅ + ⋅ ⋅ + ⋅ ⎯ ⎯→ ⎯ 2 2 ) ( Halogenated FR Mechanism Free Radical Trap mechanism Process regenerates halogen radicals to perpetuate the reaction. Phosphorus Containing FRs ¡ Additive to material it’s protecting ¡ Acts in solid phase ¢ Reacts to form phosphoric acid ¢ Acid coats to form “char” ¢ Char slows down pyrolysis step of combustion cycle Phosphorus Containing FR Mechanism ¡ Thermal decomposition leads to the formation of phosphoric acid: Phosphorus Containing FR Mechanism ¡ Phosphoric acid formed esterifies, dehydrates the oxygen-containing polymer and causes charring: Phosphorus FR Pros ¡ Efficient FR Performance ¡ Needed Dosage Lower than Halogenated FRs ¡ Does Not Produce Toxic Smoke ¡ Does Not Produce Toxic Dioxins and Furans ¢ described in more detail later Phosphorus FR Cons ¡ Higher price/kg than Halogenated ¡ Have Limited Industrial Uses because of Mechanism ¢ Char layer undesired in FR pajamas and similar products Uses of Phosphorus Containing FRs ¡ Common Uses ¢ Plasticizers ¢ Plastics ¢ Polyurethane Foam Nitrogen Containing FR Mechanism ¡ Not a fully understood mechanism ¡ What is known: ¢ Nitrogen gas is released into the atmosphere...
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Flame retardant- Presentation - Flame Retardants Group...

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