PTFE vs UHMW vs Nylon vs POM vs PEEK: Choosing the Right Engineering Plastic for Wear Parts and Bushings

A worn bushing, wear strip or guide is rarely the real problem. The real problem is usually that the material was chosen on habit ("we always use nylon") rather than on what the part actually sees: load, sliding speed, temperature, moisture and the fluid around it.

This guide is written for maintenance engineers and procurement officers who already know what a bushing or wear pad does. It compares five engineering plastics found in industrial plants across the UAE: PTFE, UHMW polyethylene, nylon, POM (acetal) and PEEK. The aim is a clear selection logic, not a datasheet dump.

Start With the Duty, Not the Material

Before comparing plastics, write down five facts about the application. They eliminate most options on their own.

• Load and contact pressure: light guide, moderate bearing load, or heavy point load?
• Sliding speed and motion: slow reciprocating, continuous rotation, or intermittent?
• Operating temperature: including the heat the part itself generates through friction, and the ambient heat of an uncooled plant or outdoor yard.
• Media: dry, oil or grease lubricated, water, solvents, fuels, cleaning chemicals.
• Tolerance requirement: does the part need to hold a tight fit, or can it tolerate some dimensional movement?

With those answers in hand, the five materials sort themselves out quickly.

PTFE: Lowest Friction, Softest Body

PTFE is chosen first for what it does not do: it barely sticks to anything, it resists almost every industrial chemical, and it has an extremely low coefficient of friction. That makes it a natural choice for dry-running sliding parts, chemical-service seats and seals, and non-stick surfaces.

The trade-off is mechanical. Virgin PTFE is soft and prone to creep, also called cold flow: under sustained load it slowly deforms. For bearing applications it is often used with fillers (glass, carbon, bronze are common) to improve load capacity and wear resistance, at some cost to the pure-PTFE friction behaviour.

• Choose it when: chemical resistance and low friction matter more than stiffness, and loads are modest.
• Avoid it when: the part must hold a precise dimension under constant load, or must carry high contact pressure unfilled.

UHMW Polyethylene: The Abrasion and Impact Specialist

Ultra-high-molecular-weight polyethylene is the standard answer for sliding abrasion with impact: conveyor wear strips, chute liners, guide rails, star wheels and wear pads. It has good impact toughness, low friction, very low moisture uptake and good resistance to many chemicals.

Its limitations are heat and stiffness. UHMW softens at relatively modest temperatures compared with nylon, POM or PEEK, so a part that sits near a hot surface or generates friction heat at speed can deform. It is also not a precision material: it is not the first pick for tight-tolerance gears or bushings.

• Choose it when: the problem is abrasive wear, impact or noise on a slow-moving sliding surface at moderate temperature.
• Avoid it when: the part runs hot, or needs high stiffness or tight dimensional control.

Nylon: Tough, Versatile, but Sensitive to Moisture

Nylon (polyamide) is one of the most widely used engineering plastics because it balances toughness, wear resistance and cost. It handles gears, rollers, bushings, sheaves and wear pads in many general industrial duties, and it takes impact and fatigue well.

The catch is water. Nylon absorbs moisture from the air and from process water, and as it does it swells and its stiffness changes. In a humid coastal plant, or a washdown area, a nylon bushing machined to a tight fit can behave differently from the same part fitted in a dry workshop. If tolerance matters, specify with moisture uptake in mind or consider a less absorbent material.

• Choose it when: you need a tough, economical, shock-tolerant wear material and dimensional drift is acceptable.
• Avoid it when: tight fits must hold in humid or wet service.

POM (Acetal): The Precision Part Material

POM, often called acetal, is stiff, dimensionally stable and has low moisture absorption. Those traits make it the usual pick for precision components: small gears, cams, bushings, rollers, fasteners and fluid-handling parts where the shape must stay true.

It has its own weak points. POM does not tolerate strong acids or strong oxidizing agents well, and unstabilised grades can degrade under prolonged UV exposure, which matters for outdoor parts in UAE sunlight. It is also less impact tolerant than nylon or UHMW.

• Choose it when: you need precision, stiffness and stable dimensions with good sliding behaviour.
• Avoid it when: the part sees strong acids, oxidizers or unprotected outdoor UV, or heavy shock loads.

PEEK: When Heat, Load and Chemicals All Apply

PEEK sits at the top of this group. It combines high mechanical strength, good wear performance, strong chemical resistance and a much higher temperature capability than the other four. It is used where a plastic must replace metal in demanding conditions: hot pump components, compressor parts, high-load bushings and wear rings.

The reason it is not used everywhere is cost. PEEK is the most expensive material on this list, so it is justified when a cheaper plastic has already failed on temperature, load or chemical attack, or when downtime from repeated replacement costs more than the part.

• Choose it when: temperature, load and chemical exposure combine, and failure of a lesser plastic is costly.
• Avoid it when: the duty is mild enough that nylon, POM or UHMW would last.

Quick Comparison

• Lowest friction and chemical inertness: PTFE
• Best abrasion and impact resistance: UHMW
• Best general-purpose toughness and value: nylon
• Best dimensional stability and precision: POM
• Best for heat, load and chemicals together: PEEK

Gulf Conditions: What Changes in the UAE

Gulf operating conditions shift the decision in a few predictable ways.

• Ambient heat: plastics lose stiffness as they warm. A part that was fine in a temperate workshop may creep or wear faster in a plant that runs hot in summer, so judge temperature at the part, not in the room.
• Humidity: coastal sites matter most for nylon, because of moisture uptake and the dimensional change that follows.
• UV: parts stored or used outdoors need a UV-stabilised grade or protection. Unprotected material left in yards or on loading docks can embrittle.
• Dust and sand: abrasive particles embed in soft surfaces and act like grinding paste. Wear-resistant grades and good sealing around the bearing point matter as much as the base polymer.

Common Selection Mistakes

1. Choosing by price alone. A cheaper bushing that fails twice as often is not cheaper once labour and downtime are counted.
2. Ignoring frictional heat. A plastic bushing on a fast shaft may run far hotter than the surrounding air.
3. Running plastic against a rough shaft. Mating-surface finish and hardness strongly affect plastic wear rate. A worn or rough shaft will chew through any plastic.
4. Forgetting thermal expansion. Plastics expand much more than steel. Fits need clearance designed for the temperature range, or the bushing will seize.
5. Copying the failed part. If the previous material failed, repeating it only repeats the failure. Read the wear pattern first: melting suggests a heat problem, scoring suggests abrasives, swelling suggests moisture or chemical attack.

A Simple Decision Path

1. Is the part chemically aggressive or dry-running at low load? Look at PTFE (filled if loaded).
2. Is the main threat abrasion or impact on a slow sliding surface? Look at UHMW.
3. Do you need a tough all-rounder and can accept some moisture effect? Look at nylon.
4. Do you need precision and stable dimensions? Look at POM.
5. Have heat, load and chemicals together defeated the above? Look at PEEK.

When an application sits between two options, share the operating details with a supplier before ordering and confirm the grade, any fillers and the machining tolerance in writing.

Sourcing Plastic Components for Your Plant

Morris supplies POM, nylon and PEEK components along with PTFE and UHMW products as part of its industrial spare parts range. You can see the wider catalogue of seals, power transmission parts, rubber products and specialty components on the industrial heavy machinery spare parts page, and an overview of what the company offers on the services page.

If you are unsure which material suits a worn part, send us the application details: load, speed, temperature, media and the failed part if you have it. Contact Morris Elevators on +971 2 555 2727 or at [email protected], or visit us at Mazyad Mall, MBZ City, Abu Dhabi, and we will help you narrow the selection.