Chemical Knowledge 07:How to Improve the Scratch and Wear Resistance of Plastics

---

Update time: 26-03-09    Views: 15

How to Improve the Scratch and Wear Resistance of Plastics

       Select an appropriate base resin

Ultra-high molecular weight polyethylene (PE-UHWM) is generally one of the most wear-resistant plastics, and selecting PE-UHWM can effectively enhance the material's wear resistance. Additionally, plastics with high crystallinity and regularity exhibit greater wear resistance, while those with higher hardness are more durable. Plastics composed of large molecules like benzene rings, such as polystyrene, are less wear-resistant. In polypropylene (PP) modification, polyolefin elastomers (POE), ethylene propylene diene monomer (EPDM), and thermoplastic vulcanizates (TPV) (e.g., dynamically vulcanized PP/EPDM) are commonly used to toughen PP. However, the addition of elastomers typically reduces scratch resistance, making the selection of an appropriate elastomer crucial. The relative order of scratch resistance is as follows:

TPV → EPDM → POE

Selection of Inorganic Fillers with Excellent Nanoscale Wear Resistance

(1) Molybdenum Disulfide  Molybdenum disulfide is primarily used as a wear-resistant additive for nylon plastics. Its functions include acting as a crystallization agent, enhancing the crystallinity of nylon, and creating a harder, more wear-resistant surface. Molybdenum disulfide exhibits strong affinity for metals. Once adsorbed onto a metal surface, its molecules fill the microscopic capillary pores visible under a microscope, further smoothing the metal surface. This characteristic makes molybdenum disulfide an ideal wear-resistant additive for applications involving friction between nylon and metal.

(2) Graphite's structure is the crystalline form of the mineral graphite, featuring a hexagonal layered arrangement. This unique chemical structure enables graphite molecules to slide past each other easily under minimal friction, a wear-resistant property particularly crucial in aqueous environments. Consequently, graphite serves as an ideal wear-resistant additive for many submerged components, such as hulls, propellers, and seals.

(3) Glass fiber can form strong mechanical bonds between polymers, thereby enhancing the structural integrity of thermoplastics and improving their wear resistance. Glass fiber provides reinforcement and improves the thermal conductivity and thermal deformation properties of plastics, significantly enhancing their load-bearing and wear-resistant capabilities.

(4) Similar to glass fiber, carbon fiber can significantly enhance the structural integrity, load-bearing capacity, and wear resistance of materials. Unlike glass fiber, carbon fiber is a relatively soft and low-abrasion fiber that does not scratch the iron or steel surfaces it comes into contact with.

Add high-strength wear-resistant additives

Polytetrafluoroethylene (PTFE) has a very low coefficient of friction, and during friction, PTFE molecules form a lubricating film on the surface of components. Under frictional forces, PTFE exhibits excellent lubricity and wear resistance, making it the best wear-resistant additive for high-load applications, such as hydraulic piston rings and thrust washers. The PTFE content in amorphous plastics is typically 15%, while in crystalline plastics, it is generally 20%.