Surface modification of carbon black by vegetable oil - Its effect on the rheometric, hardness, abrasion, rebound resilience, tensile, tear, and adhesion properties

Plasticizer (vegetable or parafinic oil) pro treated carbon black is mixed with rubber for its compounding. It is observed that the extent of cure obtained from rheometric torque decreases linearly with an increase in vegetable oil content, The presence of a coupling action and a monolayer (microplasticization) of vegetable oil at carbon black-rubber interfaces causes a decrease in tan 6 (from rheometric studies), elongation at break, and tensile strength, and increase in abrasion loss, hardness, and 300% modulus up to 3 phr, beyond which all the properties show just the opposite trend with an increase in the content of vegetable oil. Both tear strength and rebound resilience increases with increasing doses of vegetable oil; the rate of increase is slow up to 3 phr due to the coupling action and microplasticization, and it is faster beyond 3 phr due to the presence of both coupling and plasticising action. Upon the addition of a plasticizer, adhesive strength increases up to 1 phr in the case of vegetable oil, and remains almost constant in the case of parafinic oil; beyond 1 phr, adhesive strength decreases due to the presence of a multiple layer of plasticizer between rubber-metal interfaces. (C) 2002 John Wiley Sons, Inc.