Learn everything you need to know about the chemical resistance of plastics, metals like brass , and other materials. Discover how polypropylene (PP) performs in relation to isopropanol and which materials are acid-resistant . Chemical resistance of plastics.

Fundamentals of material durability

Before we delve into the chemical resistance of plastics, it is important to understand the fundamental concepts of material resistance. These include, above all, the phenomena of corrosion and aging , which significantly influence the lifespan and functionality of materials.

Corrosion refers to the undesirable degradation of materials, triggered by chemical or electrochemical reactions with the environment. This process can occur in metals such as steel or brass, but also in plastics such as polypropylene or polyamide. Factors such as temperature, pH value, chemical concentration, and duration of exposure play a crucial role.

Aging is a complex process in which the physical and chemical properties of materials change over time. This can be caused by external influences such as weathering, radiation, or chemicals, but also by intrinsic processes such as oxidation or cross-linking. Aging can lead to discoloration, embrittlement, cracking, or loss of strength and must be carefully considered when selecting materials.

To assess the durability of materials, the specific application conditions and intended uses must be considered in addition to the factors already mentioned. Only by understanding these parameters can a sound material selection be made and protection against unwanted damage be ensured.

Chemical resistance of plastics

The chemical resistance of plastics makes them indispensable in many technical applications today. Their unique chemical resistance makes them ideal materials for use in aggressive environments. However, not all plastics behave the same – it all depends on their composition.

Polypropylene (PP) is an extremely durable plastic that exhibits very good chemical resistance, even to acids, alkalis, and solvents such as isopropanol. Due to its high temperature stability and weather resistance, PP is widely used in the chemical and food industries, as well as in automotive manufacturing.

Polyethylene (PE) is also a very durable plastic. While low-density polyethylene (LDPE) is particularly valued for its flexibility and impact strength, high-density polyethylene (HDPE) is characterized by its high stiffness and acid resistance. HDPE is therefore often used for chemically stressed applications such as pipes and containers.

Polyamides (PA) , such as nylon, are also very resistant to chemicals thanks to their high strength, stiffness, and creep resistance. However, they are more sensitive to acids and alkalis than PP and PE. Polyamides are therefore primarily used in applications that are not exposed to highly corrosive media.

When selecting the right plastic material, factors such as temperature resistance, mechanical properties, and production costs play a crucial role, in addition to chemical resistance. Extensive material testing and experience are therefore essential to finding the optimal plastic solution for a given application.

Durability of metals such as brass

Besides plastics, metals are also crucial in many applications – nevertheless, the chemical resistance of plastics remains the preferred solution in many areas. In particular, acid-resistant materials such as brass , stainless steel , and aluminum are widely used in industry, laboratory equipment, and building technology.

Brass is a copper-zinc alloy valued for its high chemical resistance to many acids, alkalis, and salt solutions. The corrosion resistance of brass varies depending on the alloy composition and surface treatment. High-quality brass alloys with a higher copper content are particularly acid-resistant and are used in fittings, valves, pump housings, and other applications where high chemical stability is required.

Stainless steels are also characterized by their excellent acid resistance. The higher the chromium content in the steel alloy, the more resistant the material is to corrosion. Stainless steels are therefore preferred in laboratory, chemical, and food applications where aggressive media such as acids, bases, or salt solutions are used.

Aluminum is a lightweight but relatively corrosion-prone metal. Alloying it with additives such as copper, silicon, or magnesium significantly increases its acid resistance. Anodized aluminum surfaces offer additional protection against corrosion and are used in chemical plants, measurement and control technology, and the food industry.

Besides the right material properties, surface treatments such as coatings or anodizing are also crucial for optimizing the corrosion resistance of metals. In this way, even unalloyed steels can be made suitable for use in chemically aggressive environments through appropriate protective measures.

Practical tips for material selection

Besides metals like brass or stainless steel, which are used in many applications, high-performance plastics play a crucial role when it comes to resistance to aggressive chemicals. Take a closer look at the chemical resistance of plastics to make the right material choice.

The first step is always to carefully study the manufacturer's data sheets . Here you will find detailed information on the chemical resistance of the respective plastic, such as how the material behaves against acids, alkalis, or solvents. Pay particular attention to information on resistance to isopropanol , a commonly used cleaning agent.

Furthermore, independent materials testing institutes such as the Fraunhofer Institute offer reliable databases on the chemical resistance of various plastics and metals. Here you can search specifically for your application conditions and thus find the ideally suited material, such as PP plastic , which withstands high isopropanol exposure.

Of course, in addition to chemical resistance, factors such as temperature resistance, strength, and service life also play a crucial role. A comprehensive understanding of your specific requirements and careful examination of the material properties will enable you to make the best possible material selection for your application.

Whether plastic or metal – the chemical resistance of plastics plays a crucial role in material selection. Avoid costly damage and downtime by learning about the properties of your materials.