Differences between nylon and acetal
Acetal vs. nylon. These two materials are semi-crystalline thermoplastics, exhibiting fatigue resistance and chemical resistance. Although there are certain parallels in their properties and applications, it's crucial to recognise that nylon and acetal plastic retain their unique characteristics and cannot be seamlessly interchanged. To help you understand these materials, our guide will cover:
Chemical composition and structure: acetal vs. nylon
When we’re talking about chemical composition, what is acetal?
The term "acetal" is derived from the systematic name of the compound, which is polyoxymethylene, also called POM material. The "acetal" name originates from the chemical reaction that forms the polymer. Acetals are formed when aldehydes react with alcohols under certain conditions. In the case of polyoxymethylene, or POM, it is synthesised through the polymerisation of formaldehyde. The name "acetal" reflects the chemical structure and origin of the compound, highlighting its formation from acetaldehyde-derived monomers.
Specifically, POM material contains the functional group of a carbon bonded to two -OR groups. It has a molecular structure of (CH2O)n, as shown here:
Nylon material is a synthetic polymer that belongs to the polyamide family. Its chemical composition consists of repeating units formed from amide linkages and aliphatic hydrocarbon chains. The specific chemical structure can vary depending on the nylon materials. The image here represents nylon 6, derived from one monomer that contains six carbon atoms, hence the name nylon 6.
Nylon 6/6, shown here, derives from two monomers. The repeating unit contains six carbon atoms (hexamethylene) and two amide groups (adipamide), which form the basis of its polymer chain. Different nylon materials can have variations in the number of carbon atoms, amide groups, and other components in their repeating units, resulting in varying properties and characteristics.
You can learn more about these nylons in our guide, Nylon 6 vs. nylon 6/6.
Physical and mechanical properties: acetal vs. nylon
Nylon 6/6 is the most widely used nylon material, so let’s compare this to acetal. First, a quick review:
Summary:
| Nylon 6/6 | Acetal | |
|---|---|---|
| Tensile Strength @ Yield, 73°F | 82.74 MPa | 65.32 MPa |
| Water Absorption, Immersion Saturation | 7.0 % | 0.9 % |
| Density | 1.14 g/cm³ | 1.41 g/cm³ |
| Flexural Modulus of Elasticity | 3.10 GPa | 2.76 GPa |
| Compressive Strength – Ultimate | 2.07 MPa | 6.89 MPa |
Tensile Strength @ Yield:
Nylon 6/6: 82.74 MPa
Acetal: 65.32 MPa
What this means: Tensile strength @ yield refers to the maximum amount of tensile stress a material can withstand before it starts to deform. Nylon 6/6 has a higher tensile strength than acetal, which tells you that it can withstand higher levels of stretching forces before permanent deformation happens.
Water Absorption, Immersion Saturation:
Nylon 6/6: 7.0%
Acetal: 0.9%
What this means: Water absorption indicates a material's ability to absorb moisture from its surroundings. Note that nylon 6/6 absorbs a larger amount of water compared to acetal. This can lead to dimensional changes, altered mechanical properties, and reduced performance in wet or humid environments. Acetal's lower water absorption contributes to its dimensional stability and consistency.
Density:
Nylon 6/6: 1.14 g/cm³
Acetal: 1.41 g/cm³
What this means: Density is the measure of mass per unit volume. Acetal has a higher density than nylon 6/6, indicating that it is generally heavier for the same volume. This could affect weight considerations in specific applications where weight is a significant factor. For instance, in industries like automotive, aerospace, or any field where reducing weight is crucial, using a material with a lower density, such as nylon 6/6, could lead to lighter components without compromising other desired properties.
Flexural Modulus of Elasticity:
Nylon 6/6: 3.10 GPa
Acetal: 2.76 GPa
What this means: Flexural modulus measures a material's stiffness and resistance to bending. Both nylon 6/6 and acetal have comparable flexural moduli, but nylon 6/6 is slightly stiffer. In practical terms, this characteristic could be an advantage in applications where maintaining shape and minimising deformation is critical, such as in structural components, gears, or any situation involving bending loads.
Compressive Strength, Ultimate:
Nylon 6/6: 2.07 MPa
Acetal: 6.89 MPa
What this means: This is the ability of a material to withstand compressive forces before failure. Acetal has a higher compressive strength than nylon 6/6, suggesting that it can withstand higher loads before breaking.
Thermal properties: acetal vs. nylon
Again, we’ll compare nylon 6/6 to acetal to help you choose between these two materials. First, a quick summary of what we’ll talk about.
Summary:
| Thermal Properties | Nylon 6/6 | Acetal |
|---|---|---|
| Melting Point (Crystalline) Peak | 260.56°C | 168.33°C |
| Thermal Conductivity | 297.55 W/m²·K | 280.203 W/m²·K |
| Coefficient of Linear Thermal Expansion | 9.9 x 10-11 1/°C | 9.72 x 10-11 1/°C |
| Softening Point | 93.3°C | 104.4°C |
| Continuous Service Temperature in Air | 98.8°C | 82.2°C |
Melting Point (Crystalline) Peak:
Nylon 6/6: 260.56°C
Acetal: 168.33°C
What this means: The melting point is the temperature at which a material transitions from a solid to a liquid state. Nylon 6/6 has a significantly higher melting point than acetal, which can influence manufacturing processes, such as injection moulding. Generally, materials with higher melting points exhibit greater thermal stability, meaning they can withstand hotter temperatures without undergoing phase changes. In contrast, materials with lower melting points, like acetal, might start to soften or deform at lower temperatures.
Thermal Conductivity: acetal vs. nylon
Nylon 6/6: 297.55 W/m²·K
Acetal: 280.203 W/m²·K
What this means: Thermal conductivity measures a material's ability to conduct heat. Both materials have similar thermal conductivities, with nylon 6/6 having a slightly higher value. This translates to nylon 6/6 being slightly better at transferring heat than acetal.
Coefficient of Linear Thermal Expansion:
Nylon 6/6: 9.9 x 10-11 1/°C
Acetal: 9.72 x 10-11 1/°C
What this means: This property tells us how much a material's dimensions change with temperature variations. Both materials have similar coefficients, implying that they’ll undergo comparable dimensional changes when exposed to temperature fluctuations.
Softening Point:
Nylon 6/6: 93.3°C
Acetal: 104.4°C
What this means: The terms "softening point" and "melting point" refer to different temperature-related properties of materials, particularly how they respond to heat. The softening point doesn't involve a complete change of state like melting point does. Instead, it's a gradual transition from a rigid to a more flexible state. Acetal has a higher softening point than nylon 6/6, indicating that it can maintain its rigidity at higher temperatures compared to nylon 6/6.
Continuous Service Temperature in Air:
Nylon 6/6: 98.8°C
Acetal: 82.2°C
What this means: This is the maximum temperature at which a material can operate without significant degradation in an air environment. Nylon 6/6 can withstand higher temperatures in continuous service compared to acetal, which means it performs slightly better under elevated temperatures.
Applications and uses: acetal vs. nylon
What is acetal used for? And what about nylon? Both are commonly used to make small components for industries ranging from automotive to electronics. Our experts can help you decide which material is best for your application. Examples and their applications include:
Acetal. Provides a flexible and dynamic force when compressed. These are used in applications to maintain proper tension or prevent loosening of fasteners due to vibration.
Used for: Automotive suspension systems & engine components, medical devices, solar panel mounting, solar water heat
Nylon 6/6. Evenly distributes the load of a fastener, such as a nut, while helping to reduce heat and friction during the process of tightening. Also known as plain washers.
Used for: Electrical panels & cabinets, electronic enclosures, PCBs, telecommunications equipment, consumer electronics
Push-In Rivets – Drive Fasteners
Available in both nylon 6/6 and acetal. The hollow body increases flexibility during the insertion and removal process - making them easy to install and remove. Can also be used as a hole plug.
Nylon 6/6, used for: Automotive interior trim, consumer electronics assembly, industrial control panels
Acetal, used for: Fluid handling systems, outdoor electrical enclosures, medical equipment
Acetal. Ergonomic design allows for easy grip and rotation. Low friction, corrosion resistance, and dimensional stability make them suitable for use in environments where metal components might corrode or require insulation.
Used for: Electrical enclosure covers and panels, automotive interiors
Nylon 6/6. The ideal choice when you need a lightweight screw with electrical, corrosion, vibration and good wear resistance. Also resistant to most chemicals.
Used for: Electrical enclosures, PCBs, washing machines, refrigerators
You can learn more in our guide, What are Nylon Fasteners?
PCB spacers – Round/Unthreaded
Acetal. Provides thermal and electrical insulation between components. With lower friction than nylon, this PCB ensures that the spacer maintains its positioning and insulation properties over time, enhancing the reliability and longevity of the assembly while minimising the potential for electrical interference or mechanical damage.
Used for: Solar charge controllers and monitoring systems, medical equipment, electrical enclosures
Nylon 6/6. Good wear resistance and supports heavily loaded circuit boards. Both ends easily snap in by hand and lock into place.
Used for: PCBs in control panels
Considerations for choosing between nylon and acetal plastic
Nylon vs. acetal. The synthetic material you choose should depend on the application. These are the factors you need to evaluate:
Physical and Mechanical Properties
Nylon is known for its high-impact resistance and flexibility, making it suitable for applications that experience vibrations or require some degree of shock absorption. Nylon also has higher wear resistance.
Acetal offers good dimensional stability and strength, which can be crucial in applications requiring tight tolerances or resistance to deformation over time.
Environmental factors
Nylon absorbs more moisture than acetal, potentially leading to dimensional changes and altered mechanical properties in humid conditions.
Acetal, with its lower moisture absorption, is more appropriate for applications that require consistent dimensions in wet environments.
Chemical exposure should also be considered. Nylon generally has higher chemical resistance, but acetal has superior resistance to hydrocarbons and solvents.
Electrical properties
Nylon tends to have better insulating properties, making it suitable for applications where electrical isolation is necessary. Acetal, however, can be engineered to have insulating properties as well.
Cost and availability also play a role in the decision-making process. Nylon is often more cost-effective than acetal, which might make it more attractive for applications with budget constraints. However, acetal's durability and properties might justify its higher cost in certain scenarios.
You can also consider glass-filled nylon if you need higher strength than what nylon offers. See our guide, The Pros and Cons of Glass-Filled Nylon.
Download free CADs and try before you buy
Free CADs are available for most solutions, which you can download. You can also request free samples to ensure the product you’ve chosen is exactly what you need.
If you’re not quite sure which solution will work best for your application, our experts are always happy to advise you.
Whatever your requirements, you can depend on fast despatch. Request your free samples or download free CADs now.
Questions?
Email us at sales@essentracomponents.co.uk or speak to one of our experts for further information on the ideal solution for your application 0345 528 0474.