Why should we improve the wear resistance of plastics?
In the vast application fields of plastic products, wear resistance is a key performance indicator that plays a decisive role in the application range and service life of plastics.

As plastics are widely used in automotive manufacturing, mechanical engineering, electronic devices, and many other fields, improving their wear resistance has become increasingly important. To effectively reduce friction and wear during the use of plastics, there are currently two main approaches: adding lubricating substances and reinforcing materials.

However, while lubricants can reduce friction to some extent, they have several drawbacks.

Over time, lubricants are prone to aging, leading to a decrease in lubrication effectiveness, and they require regular addition and maintenance.     This not only increases operational costs and maintenance workload but also easily accumulates dust and debris, which can contaminate internal parts and affect the normal operation of equipment. Therefore, adding reinforcing materials to improve the wear resistance and self-lubricating properties of plastics has gradually become the preferred choice in the industry.

Now, let's take a closer look at the seven common reinforcing materials used to improve the wear resistance of plastics.

Polytetrafluoroethylene (PTFE, Teflon)

Molybdenum Disulfide (MoS₂)

Graphite

Graphite has a unique chemical structure, arranged in a lattice pattern. It is this distinct structure that allows graphite molecules to slide easily against each other with minimal friction. This wear-resistant characteristic is especially important in water environments, as the presence of water molecules increases friction between materials. The special structure of graphite effectively reduces this friction.

Due to this property, graphite is an ideal wear-resistant additive and is widely used in various applications submerged in water, such as water pump housings, impellers, and valve seals. In these applications, graphite significantly enhances the wear resistance of plastics in water environments, ensuring the long-term stable operation of related equipment in harsh, wet, and water-rich conditions. It reduces maintenance and replacement frequency, thereby lowering usage costs.

Polysiloxane

Polysiloxane liquid is a migratory wear-resistant additive. When added to thermoplastic materials, it slowly migrates to the surface of the part, forming a continuous thin film. This thin film acts like an invisible "armor," effectively protecting the part from external friction and wear. Polysiloxane has a wide range of viscosities. Generally, the lower the viscosity of polysiloxane, the more fluid it becomes, allowing it to migrate to the part's surface more quickly and provide better wear resistance.

However, if the viscosity is too low, it can evaporate more easily from the part and quickly disappear, reducing its wear-resistant effect. Therefore, when selecting polysiloxane as an additive, its viscosity must be carefully controlled based on the specific application requirements and process conditions to ensure optimal wear resistance performance.

Glass Fiber

Glass fiber is an inorganic, non-metallic material primarily made from silica, with its diameter typically ranging from a few microns to over twenty microns. Glass fiber has excellent insulation properties, high heat resistance, strong corrosion resistance, and high mechanical strength. These properties make it commonly used as a reinforcement material in plastics. Although glass fiber itself is brittle and has poor wear resistance, it plays a unique role when used to reinforce plastics.

Glass fiber provides a strong mechanical bond between polymers, like building a sturdy bridge within the molecular structure of plastic, tightly connecting individual molecules together. This increases the overall integrity of the thermoplastic structure and significantly improves its wear resistance.

Glass fiber-reinforced plastics are widely used in various mechanical parts such as water pumps, water valves, bearings, shaft sleeves, gears, supports, and rollers. In these applications, glass fiber-reinforced plastics can withstand significant mechanical stress and friction, ensuring that parts maintain good performance over prolonged operation, greatly enhancing the efficiency and service life of mechanical equipment.

Carbon Fiber

Carbon fiber is made from materials such as viscose filament, polyacrylonitrile fibers, and asphalt fibers, which are carbonized at temperatures ranging from 300 to 1000°C. Similar to glass fiber, carbon fiber can greatly improve the overall integrity, wear resistance, and load-bearing and friction resistance of plastic structures.

However, unlike glass fiber, carbon fiber is a softer and less abrasive fiber, which prevents it from scratching iron or steel friction surfaces during use. Utilizing its self-lubricating properties, carbon fiber-reinforced plastics play an important role in the production of special-purpose components, such as oil-free lubricated bearings for aviation instruments and cassette recorders, oil-free lubricated gears for electric drive diesel locomotives (to prevent accidents caused by oil leakage), and oil-free lubricated piston rings on compressors.

These applications not only fully utilize the wear-resistant properties of carbon fiber-reinforced plastics but also take advantage of its self-lubrication, reducing the need for lubrication oil and maintenance costs while improving equipment safety and reliability.

Aramid Fiber (Aromatic Polyamide Fiber)

Aramid fiber, commonly known as Kevlar, is a new high-tech synthetic fiber successfully developed by DuPont in the 1960s. Aramid fiber boasts exceptional properties, such as ultra-high strength, high modulus, high temperature resistance, acid and alkali resistance, and light weight, with strength 5 to 6 times that of steel wire. Aramid fiber is also an excellent wear-resistant additive. Compared to glass and carbon fibers, it is the softest and least abrasive fiber.

This characteristic gives aramid fiber a unique advantage in wear-resistant applications, especially in cases where the surface abrasion of mating parts is a concern. For example, in the manufacturing of tactical helmets made from aramid/high molecular weight polyethylene, the application of aramid fiber not only enhances the wear resistance of the helmet but also ensures that it can effectively disperse energy upon impact, protecting the user's safety.