Navigate the world of plastics with confidence! While polyurethane and polyethylene are both popular plastics, they have distinct characteristics that can affect your design. Understanding the key differences between polyurethane and polyethylene is crucial for product designers.

• Versatility: Explore how each material can meet unique design specifications
• Performance: Learn which option offers better durability and adaptability 
• Applications: Discover where each material excels in real world scenarios

Need help deciding? Start with our design tool or download our datasheets to learn how our advanced thermoset polyurethane solutions can meet your exact specifications.

What is Polyethylene?

Polyethylene (PE) is a material commonly found in many consumer goods. It is created through a simple chemical structure consisting of hydrogen and and carbon atoms. Depending on the desired density, polyethylene can be engineered to form either a linear or branched structure, known as high-density polyethylene (HDPE) or low-density polyethylene (LDPE). While both types share the same chemical composition, they each portray very different physical properties. HDPE is strong and stiff, while, LDPE is softer and more flexible. HDPE is strong and stiff, making it ideal for applications like toys, bins, and drainpipes, whereas, LDPE is softer and more flexible and can be commonly found in disposable gloves, bags, and plastic wrap to name a few.

What is Polyurethane?

Polyurethanes are formed through the chemical reaction between a polyol and diisocyanate. Despite their complex chemical structure, polyurethanes allow engineers to tailor the chemistry to meet specific design requirements. They can be custom formulated to be soft and flexible or hard and rigid, providing unparalleled adaptability.  As a result, polyurethanes are found in a wide range of applications, from cushioning in shoes to components in your favorite electronic devices.

Differences Between Polyethylene & Polyurethane

While polyethylene and polyurethanes stem from the same plastics family, they differ significantly in properties, product types, and manufacturing processes. Starting with the chemical structure, polyethylene is a type of thermoplastic, while polyurethane is a thermoset.

• Thermoplastics like polyethylene can be melted and reformed, making them suitable for injection molding
• Thermosets like polyurethanes are molded through cast or reaction injection molding (RIM) process and offer better performance under high temperatures due to their permanent form. 

Due to their differences, thermoset polyurethanes generally offer more robust physical properties. The table below summarizes the key distinctions between thermoset polyurethane and thermoplastic polyethylene:

Which Material Should You Choose?

Depending on your design requirements, polyurethane and polyethylene can fit into a wide range of products and components. However, thermoset polyurethanes can produce stronger, more robust products that withstand most environmental conditions. This versatility makes them ideal for applications requiring specific physical properties, such as military & defense, industrial, medical, and packaging. Polyethylene, on the other hand, is best suited for products with minimal longevity or wear life concerns, commonly found in consumer goods and packaging.

When evaluating materials, it's crucial to consider the application's requirements and corresponding manufacturing to produce efficient products based on your design needs.

To help narrow your material decisions: complete our design tool to start your custom product or download our datasheets to explore some of the superior properties available!