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« في: نوفمبر 27, 2007, 10:16:38 مساءاً »
Reinforcing carbon blacks
The highest volume use of carbon black is as a reinforcing filler in rubber products, especially tires. While a pure gum vulcanizate of SBR has a tensile strength of no more than 2.5 MPa, and almost nonexistent abrasion resistance, compounding it with 50% of its weight of carbon black improves its tensile strength and wear resistance as shown in the below table.
Types of carbon black used in tires
Name Abbrev. ASTM
Desig. Particle
Size
nm Tensile
Strength
MPa Relative
Laboratory
Abrasion Relative
Roadwear
Abrasion
Super Abrasion Furnace SAF N110 20-25 25.2 1.35 1.25
Intermediate SAF ISAF N220 24-33 23.1 1.25 1.15
High Abrasion Furnace HAF N330 28-36 22.4 1.00 1.00
Easy Processing Channel EPC N300 30-35 21.7 0.80 0.90
Fast Extruding Furnace FEF N550 39-55 18.2 0.64 0.72
High Modulus Furnace HMF N683 49-73 16.1 0.56 0.66
Semi-Reinforcing Furnace SRF N770 70-96 14.7 0.48 0.60
Fine Thermal FT N880 180-200 12.6 0.22 --
Medium Thermal MT N990 250-350 9.8 0.18 --
Practically all rubber products where tensile and abrasion wear properties are crucial use carbon black, so they are black in color. Where physical properties are important but colors other than black are desired, such as white tennis shoes, precipitated or fused silica is a decent competitor to carbon black in reinforcing ability. Silica based fillers are also gaining market share in automotive tires because they provide better fuel efficiency due to a lower rolling loss compared to carbon black filled tires. Traditionally silica fillers had worse abrasion wear properties, but the technology has gradually improved to where they can match carbon black abrasion performance
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