Choosing the wrong material in a chemically aggressive environment can lead to swelling, cracking, or sudden failure. If you’re unsure whether polyester will hold up—read on.
Polyester is resistant to many acids, oxidizing agents, and organic solvents. It performs well in contact with dilute acids, alcohols, oils, and hydrocarbons, but is not resistant to strong alkalis.
Let’s explore how polyester behaves when exposed to different chemical categories and where its resistance strengths and weaknesses lie.
Chemical Resistance Profile of Polyester
Need to choose a material for use in a chemically active process?
Polyester resists many industrial chemicals, especially dilute acids, fuels, and solvents, but breaks down in strong bases and hot alkaline environments.
✅ General Resistance Ratings:
| Chemical Group | Resistance Level | Notes |
|---|---|---|
| Dilute Acids (HCl, H2SO4)1 | ✅ Good | Excellent resistance to dilute inorganic acids |
| Alcohols (Ethanol, IPA) | ✅ Good | Does not absorb alcohols or degrade in contact |
| Hydrocarbons (fuels) | ✅ Good | Gasoline, kerosene, diesel – generally compatible |
| Oils & Greases2 | ✅ Good | Resists non-polar lubricants and oils |
| Oxidizing Agents | ⚠️ Moderate | Resistant to weak oxidizers like bleach (low conc.) |
| Alkaline Solutions3 | ❌ Poor | Swells, softens, or degrades in caustic solutions |
| Ketones, Esters | ⚠️ Limited | May be affected depending on concentration/temperature |
Polyester performs best in acidic, oily, or neutral environments, but should be avoided where alkalis or caustics are present.
Why Polyester Performs Well in Some Chemicals but Not Others?
Wondering why polyester resists acids but not alkalis?
The ester bonds in polyester’s molecular chain are stable against acid hydrolysis but vulnerable to alkaline hydrolysis. That’s why alkalis break it down.
🧪 Chemical Mechanism:
- Acid Resistance4: The ester groups remain intact in dilute acid solutions, so polyester remains stable and strong.
- Alkali Attack5: Bases (like NaOH) attack the ester linkage, breaking the polymer backbone—causing brittleness or dissolution over time.
Polyester fabrics, coatings, and seals are commonly used in oil pipelines, automotive fuel systems, and acid-tolerant environments for this reason.
Practical Applications Based on Resistance
Looking for examples of where polyester is commonly used due to its resistance profile?
Polyester is widely used in chemical-resistant textiles, coated fabrics, fuel filters, gaskets, and industrial belts.
🔍 Examples by Application:
| Industry | Typical Use | Chemical Exposure |
|---|---|---|
| Automotive | Fuel filters, wire harness sleeves | Oil, gasoline, road chemicals |
| Filtration | Liquid filter bags, cartridge filters | Alcohols, oils, low pH media |
| Packaging | Coated fabrics, liners | Mild acids, alcohols |
| Industrial Textiles | Conveyor belts, hose covers | Oils, solvents, dirt |
If the working environment includes strong caustics or high-pH detergents6, polyester should be replaced with polypropylene7 or PTFE8.
Conclusion
Polyester offers strong chemical resistance to acids, fuels, oils, and solvents, but performs poorly in strong alkalis. It’s a versatile and cost-effective material for many industrial and automotive sealing or coating applications, as long as you avoid caustic or high-pH environments.
🧪 Need rubber or seals resistant to acids, oils, or fuels?
Contact Julong Rubber or Request a Custom Quote for polyester-coated or composite rubber sealing solutions.
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Understanding how materials resist dilute acids can help in selecting the right materials for chemical applications. ↩
Exploring material resistance to oils and greases is crucial for applications in lubrication and maintenance. ↩
Knowing which materials resist alkaline solutions can prevent degradation in caustic environments, ensuring longevity and safety. ↩
Understanding Acid Resistance is crucial for applications in harsh environments, ensuring durability and performance of polyester products. ↩
Learn about Alkali Attack to better protect polyester products from degradation and extend their lifespan in various applications. ↩
Understanding high-pH detergents can help you choose the right materials for durability and safety in your applications. ↩
Explore the advantages of polypropylene, especially in harsh environments, to enhance your material selection process. ↩
Learn about PTFE's unique properties and its suitability for various industrial applications, especially in chemical resistance. ↩
