What’s a coefficient of friction?
In this article, we’ll discuss plastics with very low coefficients of friction. These materials facilitate sliding and possess an impressive resistance to friction and wear.
Let's start by looking at ways in which a low coefficient of friction plays a major role in the optimization of systems and parts. Friction is defined as the force that resists relative motion between two bodies in contact, such as the sliding of one solid object over another. The relationship between the sliding force and the holding force is expressed by the coefficient of static friction and the coefficient of dynamic friction of a material.
Static coefficient of friction: The static coefficient of friction represents the initial force required for one surface to slide over another. It therefore refers to a stationary object.
Dynamic friction coefficient: The dynamic or kinetic friction coefficient refers to the friction force measured during movement.
5 plastics with extremely low coefficients of friction
1. PTFE (Teflon®, Fluorosint® 207)
Dynamic coefficient of friction: 0.10
Thanks to its unique properties, polytetrafluoroethylene, better known as Teflon®, is a material of choice for applications where chemical and thermal stresses are too great for traditional materials. It’s a chemically inert plastic that resists a wide variety of chemical agents. With its smooth and slippery surface, PTFE is also highly resistant to wear.
Prized by a variety of industries, including the chemical and food sectors, PTFE is also used in medical and pharmaceutical applications
2. Nylon with additives (NYLOIL®)
Coefficient of dynamic friction: 0.12
Nylons are plastics with a high resistance to wear and compression. For this reason, they’re often used to manufacture durable and resistant bushings. NYLOIL® is a nylon enriched with a plant-based lubricant that allows it to self-lubricate and reduce friction.
To learn more about self-lubricating plastics, see our article: Self-Lubricating Materials: Important Assets for the Food Industry
3. UHMW (TIVAR® 88)
Dynamic coefficient of friction: 0.14
UHMWs are polyethylene plastics designed to withstand the most demanding mechanical constraints. They're light and highly resistant to friction and abrasion. TIVAR® 88 is a UHMW particularly popular when designing liners to reduce surface wear and noise levels in production environments. It also facilitates the transportation of bulk materials. These high performance plastics are developed for industrial applications.
4. UHMW (TIVAR® HPV)
Dynamic coefficient of friction: 0.09
TIVAR® HPV is a UHMW with a lubrication additive that allows it to self-lubricate, thus reducing its coefficient of friction. It’s ideal for applications where mechanical, chemical and thermal stresses are too great for standard UHMW. TIVAR® HPV is also a more suitable choice than general-purpose UHMW for applications where speed, pressure, and temperatures are high, as it maintains a longer service life under harsh conditions.
5. PET-P (Ertalyte® TX)
Dynamic coefficient of friction: 0.19
Polyethylene terephthalate (PET-P) is a thermoplastic frequently used in the food industry when designing mechanical parts subject to high loads and friction. Ertalyte® TX is a polyester enriched with a solid lubricant that reduces its coefficient of friction, allowing it to slide more easily. It's known for its superior resistance to friction and wear as well as its excellent mechanical strength.
Other plastics to consider
Dynamic coefficient of friction: 0.32
Because of its ability to withstand a wide variety of stresses and maintain performance in demanding environments, PEEK is an advanced plastic used in highly specialized material applications such as those found in the aerospace field.
Although its coefficient of friction is higher than other plastics on this list, PEEK is prized for its resistance to wear, heat and chemicals.
Acetal (Acetron® GP)
Dynamic coefficient of friction: 0.25
Acetal is a very strong, hard and rigid plastic with good wear resistance. This easily machinable material allows for the design of strong, rigid mechanical parts that will have an advantageous service life. In addition, it absorbs very little water, making it a suitable choice for humid environments.