Formulation and curing characteristics of EPDM/NR and EPDM/SBR polyblends used in metallic surfaces rubber lining

In this work, a new elastomeric liner was introduced to protect the metal surfaces of storage tanks against corroding materials in petrochemical industries. This new liner was prepared on the basis of EPDM/NR and EPDM/SBR compounds. The elastomeric compounds were cured by using super‐heated water vapor at atmospheric pressure. To increase the rate of curing in these rubber samples, the optimum curing system contained 15 phr sulfur and 1.5 phr mercaptobenzothiazole, 1.5 phr zinc diethyl dithiocarbamate, and 1.8 phr tetramethylthiuram disulfide accelerators. Mechanical tests showed that ultimate tensile strength, elongation at break, and hardness of both polyblend samples were comparable to the SBR/NR blend, which is widely used in the rubber lining of metallic surfaces. In the next step, the chemical resistance of the samples was measured by placing them in a 30 wt % HCl solution. The tensile strength, elongation at break, and weight loss of the samples were measured before and after immersion in HCl. Also, the chemical resistances for EPDM/NR, EPDM/SBR, and SBR/NR samples were qualitatively measured in caustic solution. The cracking, blistering, permeability, and adhesion of the rubber samples to steel surface were observed. Finally, the results showed that EPDM/SBR (70/30) polyblend can be a suitable substitute for conventionally used SBR/NR (50/50) for a successful rubber used to line metallic surfaces. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009