What is the Difference Between Aliphatic and Aromatic Polyurethane?

The main difference between aliphatic and aromatic polyurethane lies in their chemical structure and properties. Here are the key differences between the two:

1. Chemical Structure: Aliphatic polyurethane does not contain aromatic rings, while aromatic polyurethane contains aromatic rings in its structure.
2. UV Stability: Aliphatic polyurethane is highly UV-stable, making it more resistant to ultraviolet radiation, while aromatic polyurethane is less UV-stable and more prone to chalking when exposed to sunlight.
3. Glass Transition Temperature: Aromatic polyurethane has a high glass transition temperature, making it more brittle, while aliphatic polyurethane has a low glass transition temperature, making it more flexible.
4. Price: Aliphatic polyurethane products are usually more expensive than aromatic polyurethane products.
5. Coating Properties: Aliphatic urethane coatings are known for their excellent tensile strength, UV resistance, and water resistance, making them suitable for various applications, including roofing and flooring. On the other hand, aromatic urethane coatings have lower UV resistance and are typically used as base coats with a silicone topcoat added for UV protection.

In summary, aliphatic polyurethane is more UV-stable, flexible, and expensive than aromatic polyurethane, which has a higher glass transition temperature and is more brittle. Aliphatic polyurethane is often used in applications requiring UV resistance and flexibility, while aromatic polyurethane is typically used as a base coat with a silicone topcoat for UV protection.

Comparative Table: Aliphatic vs Aromatic Polyurethane

The main difference between aliphatic and aromatic polyurethane is their chemical structure. Aliphatic polyurethane contains a chain structure, while aromatic polyurethane contains a ring structure. Here is a comparison table highlighting the differences between aliphatic and aromatic polyurethane:

Aliphatic polyurethane is often used in industrial and building applications due to its toughness and flexibility. On the other hand, aromatic polyurethane is known for its better resistance to water, chemicals, and abrasion, but it has lower flexibility and a higher glass transition temperature.