This chemical compatibility guide serves as a starting point for determining which flexible tubing material is most appropriate for your specific application. The data presented here should not replace thorough product testing under the environmental and operating conditions to which the tubing will be exposed. Consider factors such as pressure variation, temperature range, and whether the tubing will be permanently bent or cyclically flexed. Environmental conditions like UV exposure (sunlight) or excessive humidity should also be taken into account.
Chemical Resistance Basics
There are three primary mechanisms of polymer degradation that influence these ratings:
Mechanisms of Polymer Degradation
There are three primary mechanisms of polymer degradation that influence these ratings:
Chemical Reaction
Certain fluids can alter the chemical structure of the polymer through the formation or breaking of bonds, leading to a loss of physical properties and potentially generating toxic byproducts.
Swelling
If a chemical dissolves the polymer or is absorbed into the polymer matrix, swelling occurs. This increases the distance between polymer chains, causing the tubing to soften and expand. Pressurized tubing is more likely to fail when swollen.
Plasticizer Extraction
Plasticizers are oily, low-volatility additives used mainly in PVC to enhance flexibility. They are not chemically bound to the polymer and can be removed by solvent extraction, often in combination with swelling. This process causes tubing to crack and become brittle over time. High temperatures can accelerate plasticizer evaporation, known as outgassing, and speed up chemical reactions, swelling, and extraction.
Polymer Formulations
Within any polymer class, there are numerous commercially available formulations designed for specific advantages, including chemical resistance. For instance, polyether-based TPUs resist hydrolysis and microbial attack in wet environments but are unsuitable for oils and grease. Conversely, polyester-based TPUs perform well with oil and grease but should avoid frequent or continuous water contact. Even two ether-based TPUs with similar mechanical properties may not perform identically under the same conditions.
Disclaimer: The information in this guide is sourced from materials believed to be accurate. However, Grayline does not warrant the accuracy or completeness of the information or the suitability of any material for any purpose. Grayline tubing products are sold with the condition that purchasers make their own assessment of suitability for their particular application. Purchasers assume all risks and liability for the use of these products, including following the seller’s recommendations.