CHEMICAL RESISTANCE DATABASE See how engineering plastics resist different chemicals
Our chemical resistance guide provides you with information on what chemicals and fluids are known to attack or be compatible with engineering plastics.
Chemical compatibility of engineering plastics What is chemical resistance?

Chemical resistance describes the ability of a material to withstand a chemical attack for a specific period without significant deterioration of its performance properties. Materials with high chemical resistance are also likely to be resistant to material breakdown due to a chemical attack. 

Chemical resistance can be a significant advantage of engineering plastics over metals, allowing end products to withstand harsh environmental conditions, disinfection, and cleaning. If a material has insufficient chemical compatibility for the application, the consequence could be cracking, swelling, softening, and shortened service life.

When selecting the appropriate chemically resistant plastic, engineers should consider the specific influencing factors in their application, such as operating temperature, mechanical load, or fire performance requirements. At Mitsubishi Chemical Group, we offer a portfolio of chemically resistant engineering plastics that offer high reliability and operational safety. 

Why choose chemically resistant engineering plastics over metals?

When it comes to chemical resistance, engineering plastics offer many advantages over metals.

Additional coatings may help metal resist chemicals, but this extra layer can add lead time and costs. A plastic with the right chemical compatibility, on the other hand, will require no secondary finishes, resulting in a faster tooling process and a more lightweight part for improved performance. 

ENGINEERING CONSIDERATIONS What factors affect the chemical resistance of plastics?
Engineering plastics can be used for applications that require exposure to acids, bases, and other industrial chemicals. However, there are a few factors that will influence the chemical resistance of your material that need to be considered to prevent part failure or a chemical attack.

Physical absorption

While this does not affect the molecular structure of the polymer, it does affect the physical structure. When chemicals are absorbed into the plastic, it can cause the part to soften, change in dimension, or fluctuate in weight.

Temperature

Exposing your material to continuous high operating temperatures can increase the effect of a chemical attack and will escalate physical absorption.

Chemical concentration

What is the concentration of the chemicals to which your material will be exposed? Knowing the conditions of how the material will be used is a critical criterion to understand if it will be chemically resistant. Higher concentrations of chemicals are more likely to harm engineering plastics than diluted solutions

What causes a chemical attack?

A chemical attack occurs when plastic and a chemical are not compatible. The chemical causes the polymer structure to weaken or break down, leading to a loss of performance properties which can in turn cause part failure. A chemical attack can also lead to ESC (environmental stress cracking) which is a thin, spiderweb-like cracking that could seriously affect a part's performance.   

In your application, you may be experiencing part failure due to a chemical attack, but what may have caused this? Common sources of chemical exposure in operating environments include:

Washdowns: Cleaning processes used to sterilize, disinfect, and sanitize conveyors, mixing equipment, and other machines that could harbor harmful bacteria, viruses, and other contaminants. This process is usually seen in the Food and Beverage and Pharmaceutical industries. Making sure you are using a plastic that is both food contact compliant and can withstand chemical exposure at high temperatures is crucial in these cases.

Lubricants: Does your application require lubricants to be successful? Some lubricants (mineral or synthetic-based) can cause plastics to crack and swell over time. Engineers and designers should consider  if the material will encounter lubricants, oils, or grease within the application. It may take prolonged exposure to the lubricant or grease for the damage to appear.
 

Additional considerations when using chemically resistant plastics

When selecting a material with the correct chemical resistance for your application, you must also consider what physical conditions your part will be exposed to:

Fire performance:
Does your application need to include specific fire performance requirements, along with being chemically resistant? Keep in mind that flame retardants can affect the chemical resistance of your material.

Electrical performance:
This is important to consider when storing media with a low flash point, such as lubrication and heating oils and petrol. 

Weather exposure:
When certain materials are exposed to severe weather or UV radiation for an extended time, they can be physio-chemically influenced by atmospheric oxygen. Loss of mechanical properties, discoloration, and brittleness may occur.    
 

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