EFFECT OF PLASTICIZER EXTRACTION BY JET FUEL ON A NITRILE HOSE COMPOUND

ABSTRACT Seven ester plasticizers were evaluated in a reference acrylonitrile–butadiene rubber (NBR) fuel hose compound with respect to extractability resistance to jet fuel. Plasticizers differed primarily in chemical structure (polarity) and molecular weight (monomeric vs polymeric). Plasticizer addition led to lower viscosity, maximum torque, modulus, tensile strength, and enhanced low temperature properties. Exposure to jet fuel caused plasticizer extraction resulting in compound softening due to absorption of the aromatic components in the fuel. The glass transition temperature shifted toward lower temperatures. Extraction resistance is enhanced by optimizing polymer–plasticizer compatibility and by using a higher molecular weight plasticizer. The use of the polymeric plasticizer A-8600 lowers the loss of other fugitive plasticizers, indicating the presence of specific plasticizer–plasticizer interactions. Of the monomeric and polymeric plasticizers, trioctyl trimellitate and A-8600, respectively, display the best combination of plasticizing ability and extraction resistance.