AbstractNatural rubber–polyolefin (70/30) blends have been studied by incorporation of modified rubber and plastic phases with a view to make the heterogeneous phases compatible. The modified rubbers used were epoxidized natural rubber (ENR) and sulfonated ethylene–propylene diene rubber (S‐EPDM) at a level of 20 parts. Other rubbers such as chlorinated polyethylene (CPE) and ethylene propylene diene rubbers (EPDM) were also used at a level of 20 parts in the natural rubber–polyethylene (NR/PE) systems. The plastic phase was chemically modified with maleic anhydride (MA) in presence of benzoyl peroxide (BPO) and used at a concentration of 10 of PE, i.e., PEm. The tensile properties such as the modulus, elongation at break, tensile strength, and hysteresis were studied. NR/ENR/PEm/PE shows the greatest improvement in tensile strength (45 over control NR/PE). NR/S‐EPDM/PEm/PE also shows similar improvement, although the hysteresis loss decreases. The change in these properties could be related to the adhesive strength. This was found to be improved by the incorporation of modified rubber and modified plastic phases. The best adhesion values have been obtained with NR/ENR/PEm/PE and NR/S‐EPDM/PEm/PE. Thus, a correlation between tensile and adhesive strength was obtained for all the systems. The increase in adhesive strength is due to chemical reactions between the various phases. Probable chemical reactions have been suggested. Morphological observations show that the phases are interpenetrating, and this is consistent with the increased tensile strength. The natural rubber–polypropylene (NR/PP) systems do not offer good strength properties with the modified PP and modified rubbers. The adhesive strength also decreases with the incorporation of the modified system. The hysteresis properties show som
展开▼
