What is the Difference Between Delrin and Acetal?

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Delrin and Acetal are both polyoxymethylene (POM) polymers, but they have some differences in their composition and properties. Here are the main differences between Delrin and Acetal:

  1. Composition: Delrin is a homopolymer, while Acetal can be either a homopolymer or a copolymer.
  2. Tensile Strength: Delrin has higher tensile strength, making it ideal for structural models.
  3. Impact Resistance: Delrin is more resistant to impact.
  4. Friction: Delrin features lower friction.
  5. Chemical Resistance: Acetal excels in chemical resistance and maintains good structural stability due to its crystalline structure.
  6. Stiffness, Flex Fatigue Resistance, and Creep Resistance: Delrin offers better stiffness, flex fatigue resistance, and creep resistance compared to Acetal.
  7. Cost: Acetal is generally a better choice for maker projects, as Delrin can be more expensive.
  8. High-Temperature Exposure: Acetal is better suited for continuous high-temperature exposure, while Delrin is better for continuous cyclic loading applications.

Both materials have excellent properties and are used in various industries, including automotive, construction, consumer goods, electronics, and food processing. They are often used interchangeably, but it is essential to consider the specific requirements of your application when choosing between Delrin and Acetal.

Comparative Table: Delrin vs Acetal

Here is a table comparing the differences between Delrin and Acetal:

Property Delrin Acetal
Type of Polymer Homopolymer Copolymer
Chemical Composition CH2O repeating units CH2O repeating units with added comonomers
Crystallinity Large crystalline structure due to organized slacking of polymer Disrupted organization due to added comonomers
Hardness Slightly higher hardness compared to acetal Lower hardness compared to Delrin
Chemical Resistance Excellent, but susceptible to hydrocarbon solvents and aromatics Better resistance to hot water and strong caustic solutions
Temperature Tolerance Cannot be used in high-temperature applications Not designed for high-temperature applications
Mechanical Strength Higher tensile strength and flexural yield strength compared to acetal Lower tensile strength and flexural yield strength compared to Delrin

Delrin is a homopolymer made of repeating CH2O units, while acetal is a copolymer with added comonomers. Delrin has a large crystalline structure due to the organized slacking of the polymer, while the added comonomers in acetal disrupt its organization. Delrin has slightly higher hardness and mechanical strength compared to acetal. However, acetal offers better resistance to the effects of hot water and strong caustic solutions. Both materials share excellent chemical resistance but are not suitable for high-temperature applications.