Question

What are two nonhalogenated fire retardants?

Short answer

Two nonhalogenated fire retardants are aluminum hydroxide and magnesium hydroxide.

Step-by-step solution

Understand Fire Retardants

Fire retardants are substances that are used to prevent or slow down the burning of materials. They can be categorized into different types, including halogenated (containing halogens like bromine or chlorine) and nonhalogenated (not containing halogens). In this problem, we're focusing on nonhalogenated fire retardants.

Identify Nonhalogenated Options

Look for fire retardants that do not belong to the halogenated category. Common nonhalogenated fire retardants include phosphorus-based compounds and mineral-based retardants such as aluminum hydroxide and magnesium hydroxide.

Select Two Examples

From the list of nonhalogenated fire retardants, choose two examples. Suitable options include phosphorus-based retardants and mineral-based options like those mentioned in the previous step.

Key concepts

Fire Retardants

Fire retardants are materials or substances that help slow down or completely halt the combustion process in materials they protect. They are crucial in minimizing fire damage, helping in containment, and safeguarding both lives and structures. Fire retardants function in various ways, such as by forming a protective layer that prevents combustion or releasing chemicals that interfere with the burning process.

There are two main types of fire retardants:

• **Halogenated:** These contain halogens like bromine or chlorine.
• **Nonhalogenated:** These do not have halogens and are seen as more environmentally friendly options.

In this article, we'll delve into the details of nonhalogenated fire retardants, exploring some common examples and their mechanisms.

Phosphorus-based Compounds

Phosphorus-based compounds are a popular choice for nonhalogenated fire retardants. These work primarily by promoting a process called charring in combusting materials. When heated, phosphorus compounds decompose to form phosphoric acid, which causes the material to char.

The formation of this char layer acts as a barrier, insulating the underlying material from the heat of the fire. This helps in two ways:

• It reduces the material's ability to sustain and propagate a flame.
• It protects the structural integrity of the material being shielded.

Phosphorus-based retardants are often used in various applications due to their effectiveness and environmental considerations compared to halogenated counterparts.

Mineral-based Retardants

Mineral-based retardants cover a broad category of fire retardants derived from natural minerals. These are highly effective in reducing flammability due to their physical and chemical properties. When exposed to heat, these minerals undergo endothermic reactions, absorbing significant amounts of heat energy and releasing water vapor.

This process cools the material and dilutes combustible gases, slowing down or extinguishing the fire. Two common mineral-based fire retardants are aluminum hydroxide and magnesium hydroxide. They are widely used due to their effectiveness, availability, and cost-efficiency.

Aluminum Hydroxide

Aluminum hydroxide is a mineral-based fire retardant known for its significant fire suppression abilities. When exposed to heat, it undergoes a chemical reaction where it decomposes to release water vapor and transform into aluminum oxide.

This decomposition has multiple benefits:

• Water vapor helps cool the flames and the surface of the material.
• Aluminum oxide forms a protective layer over the material.

This dual-action helps in both cooling the fire and protecting the material underneath from direct flames. Aluminum hydroxide is often used in plastics and rubber, making them safer in fire incidents.

Magnesium Hydroxide

Magnesium hydroxide is another excellent mineral-based nonhalogenated fire retardant. Similar to aluminum hydroxide, it decomposes when exposed to high temperatures, releasing water vapor and forming magnesium oxide.

Its decomposition provides:

• A cooling effect through the release of water vapor.
• A barrier against flames with the formation of magnesium oxide.

These properties make magnesium hydroxide an effective retardant for a variety of materials, including industrial products and construction materials. Its value is recognized not only in fire resistance but also in its non-toxic by-products, making it a safer alternative in fire retardant applications.