Carbon/Carbon Fiber Filled PTFE

Carbon/Carbon Fiber Filled PTFE

Carbon Fiber Filled PTFE

• Carbon fiber (CF) is an inorganic non-metallic material, whose many physical and mechanical properties are comparable to metals. It has high strength, high temperature and pressure resistance, corrosion resistance, and light weight.
• CF/PTFE composite material has the advantages of good chemical resistance and high mechanical properties, strong damage resistance, high temperature resistance. It can be widely used in pneumatic seals, guide rings, bearing bushes, piston rings, guide rails, military products and other industries. It is also particularly suitable for use in occasions with water media.
• Compared with glass fiber reinforced PTFE, which is also a hard filler, in addition to the difference in electrical properties and color, the comprehensive performance of CF/PTFE is significantly better than that of glass fiber reinforced polytetrafluoroethylene.
• Carbon fiber can also be filled into PTFE together with graphite, glass fiber, copper powder, etc. CF/PTFE can be used well in environments such as acid-based media, organic solvents, and fuels.

Table 1. Comparison of performance parameters of different content of carbon fiber filled PTFE

	High-filled CF/PTFE	Medium-filled CF/PTFE
Color	Black	Black
Density g/cm3	2.05	2.1
Shore hardness D	73	70
Insulation	Conductive	Conductive
Chemical property	Acid-resistant,alkali-resistant, and most chemical resistant
Tensile strength (MPa)	19.4	23.1
Elongation at break (%)	160	200
Ball indentation hardness	34.0	31.7
Compressive strength	28.0	22.5
Coefficient of friction (dry)	0.16	0.17
Coefficient of friction (oil)	0.024	0.026

Carbon Filled PTFE

• Carbon powder (CA) is also known as carbon black. The arrangement of carbon atoms in carbon powder is similar to graphite, which has the characteristics of electrical conductivity and heat conduction.
• The carbon powder is filled into PTFE, which mainly improves the wear resistance, thermal conductivity and creep resistance of PTFE. It can be widely used in hydraulic and pneumatic seals, guide rings, piston rings, retaining rings, bushings, etc.

Figure 1. SEM images of brittle split surfaces of filled PTFE with different carbon content [1]

• Carbon powder can also be filled into PTFE together with graphite, carbon fiber, glass fiber, copper powder, etc. to achieve better use effect.
• CA/PTFE is not suitable for use in aqueous media. CA/PTFE and graphite reinforced polytetrafluoroethylene have similar performance. The friction coefficient of CA/PTFE is slightly greater than graphite reinforced polytetrafluoroethylene, and the rigidity is stronger than graphite reinforced polytetrafluoroethylene.

Table 2. Carbon powder filled PTFE (CA/PTFE) performance parameters

	High-filled CF/PTFE
Color	Black
Density (g/cm3)	2.1
Shore hardness D	72
Insulation	Conductive
Chemical property	Acid-resistant, alkali-resistant, and most chemical resistant
Tensile strength (MPa)	14.0
Elongation at break (%)	220
Coefficient of friction	0.2

Note: The above data is for reference only. The actual product in use may vary due to different parts size, raw material batch type, and mechanical working conditions. In addition, the filled PTFE is a multi-element composite material, and the proportioning composition can be adjusted according to the actual working conditions of the customer, which is not fixed.

Reference

1. V. N. Aderikha, V. A. Shapovalov, Yu. M. Pleskachevskii, Journal of Friction and Wear 29 (2008) 120–126.

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