What Are the Most Common Structural Foam Plastics?

As a popular manufacturing process, structural foam molding has become increasingly popular for creating large-tonnage plastic products. Structural foam plastic offers many benefits including design flexibility, high moldability, and durability. 

There are two common types of structural foam plastic used in this manufacturing process, each of which exhibits its own properties and benefits. Typically, customers choose from structural foam polyethylene or structural foam polypropylene depending on what characteristics they desire and need in their products. In this blog, we will explore each of these plastics and what they are best used for. 

Structural Foam Polyethylene

Polyethylene is the most commonly produced plastic. It is a durable, lightweight, closed-cell material that is found in many everyday household items as well as demanding applications.

Properties of Polyethylene

As a commonly produced plastic, polyethylene has many beneficial properties. This polymer exhibits good chemical, wear, and water resistance, as well as electrical insulation, good load bearing, and shock absorption. 

If you are interested in learning more about structural foam polyethylene in detail, check out our blog. 

Low-Density Polyethylene (LDPE) Versus High-Density Polyethylene (HDPE)

There are two common types of polyethylene, low-density polyethylene (LDPE) and high-density polyethylene (HDPE). Each has its own applications and advantages, however, HDPE is typically what is used in structural foam molding. 


Low-density polyethylene exhibits low-temperature flexibility, toughness, and corrosion resistance. However, due to its low melting point, LDPE is not suitable for applications where temperature resistance and strength are required. LDPE is not suitable for structural foam molding due to its lack of strength. 


High-density polyethylene has a high melting point, high strength, good chemical resistance, and good crack resistance. Since this polymer exhibits such good physical properties, HDPE is ideal for applications where strength and durability are required, thus making it suitable for use in structural foam molding. 

Structural Foam Polypropylene

Polypropylene is a rigid, lightweight, closed-cell polymer that is commonly used in various industries, including consumer goods, automotive, medical, and more. This polymer is commonly used in structural foam molding because of its numerous beneficial properties. These benefits include toughness, flexibility, fatigue resistance, chemical resistance, high-temperature resistance, good electrical insulation, compression resistance, impact resistance, and moisture resistance.  

These properties allow for structural foam molded products made from polypropylene to be used in critical and demanding applications. These include applications that are primarily outside, under UV light, exposed to chemicals and weather, or in varying temperatures. 

If You Are Looking for Structural Foam Plastics, Turn to Port Erie

Since 1953 Port Erie has been creating high-quality structural foam plastics. We primarily work with HDPE and polypropylene to manufacture durable, cost-effective structural foam molded products. Our team has created structural foam molded products for lawn and garden applications, the construction industry, and many more. 

Not only do we have the ability to create structural foam molded products, but we also can create products through automated injection molding. We have automated robots that we use to create quality injection-molded products with minimal errors in an efficient timeline. Our team also has the ability to engineer and create tools and molds for both structural foam molding and injection molding products, so if changes need to be made, we can do that in-house. 

We also offer secondary operations including finishing and assembly, and warehousing and distribution. That way, your products can be stored and shipped directly from our manufacturing facility to ensure quick turnaround and delivery times. 

If you are ready to get started on your structural foam plastics project, contact our team today.

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