Water absorption behavior and its effect on tensile properties of ethylene–propylene–diene–terpolymer/polypropylene/filler ternary composites: a preliminary study

Abstract

The water absorption behavior of white rice husk ash (WRHA) and silica filled ethylene-propylene-diene-terpolymer/polypropylene (EPDM/PP) ternary composites was studied with special reference to filler type, test specimen preparation (die cut or molded), and dynamic vulcanization of elastomer phase. The water uptake of composites was recorded as a function of them over 40 days of immersion period in distilled water. The influence of final water uptake on tensile properties of the composites was also studied. White rice husk ash filled composites and molded composites exhibit lower water uptake when compared to silica and die cut composites, respectively. All vulcanized composites showed lower water uptake than the unvulcanized composites. After the immersion period in water, tensile properties of unvulcanized composites were almost unaffected while vulcanized composites exhibit an increase in the tensile properties. None of the composites reached the equilibrium state within the immersion period. The results of this preliminary study suggest the importance of in-depth study of water absorption–tensile property correlation of this ternary system over a large span of time till the equilibrium state is reached. It is further revealed that the water absorption behavior depends on the characteristics of the test specimen used. *On study leave from the Rubber Research Institute of Sri Lanka.