01 Select the appropriate base resin
Usually ultra-high molecular weight polyethylene (UHWMPE) is one of the most wear-resistant plastics, and choosing UHWMPE can easily improve the wear resistance of the material. In addition, high crystallization, high regularity of plastics are more wear-resistant, high hardness of plastics are more wear-resistant, and plastics composed of large molecules similar to benzene rings are less wear-resistant, such as polystyrene. In polypropylene (PP) modification, polyolefin elastomer (POE), ethylene propylene terene rubber (EPDM), thermoplastic dynamic vulcanized rubber (TPV) (such as dynamic vulcanized PP/EPDM) is usually used to toughen PP, and the addition of elastomers generally leads to a decline in scratch resistance, so it is very important to choose the appropriate elastomer. The order of scratch resistance is as follows: TPV > EPDM > POE.
02 Packing with good wear resistance
(1) Molybdenum disulfide
Molybdenum disulfide is a wear-resistant additive mainly used in nylon plastics. Molybdenum disulfide acts as a crystallizing agent to increase the crystallinity of nylon, making the nylon material produce a harder and more wear-resistant surface. Molybdenum disulfide has a high affinity for metals, and once adsorbed on the metal surface, molybdenum disulfide molecules will fill the pores on the metal surface that can be seen with a microscope, and make the metal surface smoother, which makes molybdenum disulfide an ideal wear-resistant additive for nylon and metal friction occasions.
(2) Graphite
The chemical structure of graphite is a unique lattice structure, which makes the graphite molecules easily slide each other when subjected to little friction. This wear resistance is especially important in the environment with water, so graphite is an ideal wear-resistant additive for many parts placed in water. Such as water laying shell, impeller and Value seals.
(3) Glass fiber
Glass fiber can form a strong mechanical bond between polymers, so glass fiber can improve the integrity of thermoplastic structures and improve wear resistance. Glass fiber reinforcement can improve the thermal conductivity and thermal deformation of plastics, and can significantly improve the load resistance and wear resistance of plastics.
(4) carbon fiber
Similar to the case of glass fiber, carbon fiber can greatly improve the integrity of the material structure, load resistance and wear resistance. Unlike glass fiber, carbon fiber is a softer and less scratchy fiber, and carbon fiber will not scratch the friction surface of iron or steel against which it is rubbed.
(5) Aromatic polyamide fiber
Aromatic polyamide fiber is also one of the wear resistant additives, unlike glass fiber and carbon fiber, it is the softest and most scratch free fiber, this property is the main advantage of aromatic polyamide fiber in wear resistant applications.
03 Add suitable wear-resisting additives
(1) Polytetrafluoroethylene (
PTFE)
PTFE has a very low coefficient of friction, and PTFE molecules form a lubricating film on the surface of the part during friction. PTFE has good lubricity and wear resistance under friction, and is the best wear resistant additive in high load applications. These high-load applications include hydraulic piston ring seals and thrust washers. The PTFE content in amorphous plastics is generally 15%, and in crystalline plastics is generally 20%.
(2) polysiloxane
Polysiloxane liquid is a migratory wear-resistant additive that, when added to thermoplastics, slowly migrates to the surface of the part and forms a continuous film. The viscosity of polysiloxane is more low, the more quickly it can migrate to the surface of the part to provide wear resistance, but the viscosity of polysiloxane can not be too low, otherwise it is easy to volatilize, and will quickly disappear from the part.
(3) Smoothing agent
Such as oleic acid amide, erucic acid amide and other smoothing agents, when they are added to the thermoplastic, will migrate to the surface of the parts to produce a wax layer, reducing the coefficient of friction and also reduce the visibility of scratches, the disadvantage is that it can not completely improve the surface sticky phenomenon.
