Plastic is one of the most pervasive material families used for commodity and engineering parts in the world today. Estimates suggest that global plastic production now exceeds 300 million tons annually – as much as 80% of which is comprised of thermoset resins and thermoplastics. How do these materials differ, and what market sectors do they serve?

In this blog post, Strongwell explores how and why thermoset resins and thermoplastics are used in the world today.

Thermosets vs Thermoplastics: A Comparison

Thermoset resins and thermoplastics are distinct from one another due to their dissimilar thermodynamic properties. Each material is strengthened by the application of heat, but once thermosets have adopted an initial shape via heat treatment, they cannot be cured further or remolded. By comparison, the shape of cured thermoplastics can be adjusted by reheating and remolding the finished part. This occurs without underlying chemical modifications.

The actual temperature performance of thermosets and thermoplastics varies, even within grades, due to the complex nature of polymeric structures. Average molecular weight (MW) and MW distribution, branching, the presence of additive agents, and polymer purity can have a significant impact on the continuous and peak use temperatures of finished parts. As a result, we must resort to a generalized comparison of thermoset and thermoplastic properties.

The key difference between the two is that thermoplastics have a comparatively low melting point and can be reformed, while thermoset resins generally withstand higher operating temperatures with little-to-no loss of the parts’ structural integrity.

Applications of Thermoplastics

Thermoplastics are essential for injection molding, one of the world’s most popular parts manufacturing processes. They are used to generate various goods using a choice of industrial technologies. Common thermoplastic materials include acrylonitrile butadiene styrene (ABS), acrylics, polycarbonate, polyester, polypropylene, and nylon. These are used to manufacture a wide range of commodity and engineering parts, from clothing to high-performance medical equipment.

However, injection moulding is an energy-intensive process that is cost-inefficient. Thermoplastics are also largely unsuited to high-temperature environments or conditions where temperatures change rapidly.

Applications of Thermosets

Thermoset resins are liquefied polymers that achieve a permanent mechanical state after curing due to irreversible cross-linking during the heating phase. This produces a rigid part that is impervious to melting, even in high peak and rapidly cycling temperatures. Epoxies and phenolics are among the most popular thermosets available to modern manufacturers, due to their high-strength and lightweight mechanical properties in the finished form. Phenolics are also notably resistant to direct flame impingement, making it uniquely suited for industrial applications and petrochemical facilities. Yet, thermoset resins are applicable to an enormous range of additional market sectors.

Commonly integrated into pultrusion systems in the manufacture of fiber-reinforced polymers (FRP), thermosets are used to manufacture parts for applications as varied as architecture and construction, utilities, security, hotel and leisure, transportation, water and wastewater, infrastructure, recreation, and much more.

Thermosets are increasingly desired over thermoplastics as they are inherently resistant to temperature-dependent deformation and have proven themselves in severe outdoor applications. If you would like to learn more about the use of thermosets in pultrusion of fabricated parts, read our previous blog post: How and Why are Thermoset Resins Used in Pultrusion?

Thermoset Resins in Strongwell FRP

Strongwell is one of the world’s leading manufacturers of FRP using innovative pultrusion technologies. If you have any queries about the specific thermoset resins available with our catalog of products, simply contact a member of the team today.

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