Impact Strength: Flat Polycarbonate Lexan Explained

The term ‘Impact Strength’ refers to the ability of a material to resist damage when subjected to a sudden force or impact. In the context of Flat Polycarbonate Lexan, a popular thermoplastic material known for its impressive strength and durability, understanding impact strength is crucial. This article will delve into the specifics of impact strength, focusing on how it pertains to Flat Polycarbonate Lexan.

Flat Polycarbonate Lexan, often simply referred to as Lexan, is a type of polycarbonate resin thermoplastic. It is widely used in various industries due to its high impact strength, transparency, and versatility. This article will explore the impact strength of Lexan, its significance, how it is measured, and factors that can affect it.

Understanding Impact Strength

Impact strength, also known as toughness, is a measure of a material’s ability to absorb energy during plastic deformation. This property is crucial in determining how a material will respond when subjected to sudden forces or impacts. High impact strength indicates that a material can absorb a significant amount of energy before fracturing, making it resistant to breakage upon impact.

Impact strength is typically measured using a pendulum impact tester, where a pendulum is swung from a certain height to strike the material. The energy absorbed by the material is then calculated based on the height the pendulum reaches after the impact. The higher the absorbed energy, the greater the material’s impact strength.

Impact Strength in Polymers

Polymers, such as Lexan, often exhibit high impact strength due to their molecular structure. The long, chain-like molecules can stretch and deform under stress, allowing the material to absorb energy rather than fracturing. This makes polymers ideal for applications where impact resistance is crucial.

However, the impact strength of polymers can vary significantly depending on factors such as temperature, strain rate, and the presence of any additives or fillers. Therefore, it is important to consider these factors when selecting a polymer for a specific application.

Impact Strength vs. Tensile Strength

While impact strength measures a material’s resistance to sudden forces, tensile strength measures its resistance to forces that attempt to pull it apart. Although these properties are related, they are not the same. A material can have high tensile strength but low impact strength, or vice versa.

For example, glass has high tensile strength but low impact strength, meaning it can resist being pulled apart but shatters easily upon impact. On the other hand, rubber has low tensile strength but high impact strength, meaning it can absorb a lot of energy upon impact without fracturing, but it can be easily stretched or deformed.

Flat Polycarbonate Lexan and Impact Strength

Flat Polycarbonate Lexan is renowned for its high impact strength. In fact, it is one of the toughest transparent thermoplastic materials available, with an impact strength up to 250 times that of glass and 30 times that of acrylic. This makes Lexan an excellent choice for applications where impact resistance is paramount.

Lexan’s high impact strength is largely due to its unique molecular structure. The polycarbonate molecules in Lexan are linked together in a three-dimensional network, which allows the material to deform and absorb energy upon impact rather than fracturing. This network also gives Lexan its excellent thermal stability and resistance to chemicals and UV radiation.

Factors Affecting Lexan’s Impact Strength

While Lexan inherently has high impact strength, certain factors can affect its performance. These include temperature, the rate of impact, and the presence of any additives or fillers. For instance, Lexan’s impact strength can decrease at very high or very low temperatures. Similarly, a very fast impact can cause the material to behave more brittle, reducing its impact strength.

Additionally, certain additives or fillers can enhance or reduce Lexan’s impact strength. For example, adding glass fibers can increase the material’s rigidity and tensile strength but may reduce its impact strength. Therefore, it is crucial to consider these factors when selecting Lexan for a specific application.

Improving Lexan’s Impact Strength

There are several ways to enhance Lexan’s impact strength. One common method is through the addition of impact modifiers, which are substances that improve a polymer’s toughness. These modifiers work by promoting plastic deformation over fracture, allowing the material to absorb more energy upon impact.

Another method is through annealing, a heat treatment process that relieves internal stresses in the material. This can improve Lexan’s impact strength by preventing premature fracture. However, it’s important to note that these methods can also affect other properties of the material, such as its transparency and chemical resistance.

Applications of Flat Polycarbonate Lexan

Due to its high impact strength, Flat Polycarbonate Lexan is used in a wide range of applications. These include bulletproof windows, riot shields, eyewear, and electronic equipment housings. Its transparency also makes it ideal for applications where clarity is important, such as in automotive windshields and aircraft canopies.

Furthermore, Lexan’s excellent thermal stability and chemical resistance make it suitable for use in harsh environments. For example, it is often used in outdoor signage, greenhouses, and solar panels, where it can withstand exposure to sunlight, rain, and temperature fluctuations without losing its impact strength or clarity.

Considerations When Using Lexan

While Lexan’s high impact strength makes it an excellent material choice for many applications, there are certain considerations to keep in mind. For instance, although Lexan is resistant to many chemicals, it can be damaged by certain solvents, such as acetone. Therefore, it’s important to consider the environment in which the material will be used.

Additionally, while Lexan is UV-resistant, prolonged exposure to sunlight can cause the material to yellow over time. This can be mitigated by applying a UV-resistant coating to the material. Finally, while Lexan is scratch-resistant, it is not scratch-proof. Therefore, in applications where scratch resistance is crucial, a hard coating may be applied to the material.


In conclusion, impact strength is a crucial property of Flat Polycarbonate Lexan, contributing to its versatility and widespread use in various industries. Understanding this property, how it is measured, and factors that can affect it, is essential when selecting Lexan for a specific application.

With its high impact strength, excellent thermal stability, and resistance to chemicals and UV radiation, Lexan is a robust and reliable material choice for many applications. However, it’s important to consider the specific requirements of each application and the potential effects of any additives or fillers on the material’s properties.

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