Compatibilization of Natural Rubber/EPDM Blends by Anhydride- and Mercapto-functionalized Copolymers

摘要

The compatibilization of natural rubber (NR)/ethylene-propylene-ethylidenenorbornene (EPDM) rubber blends was performed by using anhydride- and mercapto-functionalized copolymers. EPDM functionalized with mercapto (EPDMSH) and anhydride groups (EPDM-g-MA), as well as ethylene-vinyl acetate copolymer (EVA) functionalized with mercapto (EVASH) and anhydride groups (EVA-g-MA) were employed in small proportion in NR/EPDM (70:30 wt.%) blends. All functionalized copolymers resulted in an improvement of ultimate tensile strength, but the best results were achieved with the addition of 2.5 phr of EVA-g-MA. The rheological experiments performed on a rheological processing analyzer (RPA) revealed that the addition of small amount of EVASH resulted in a substantial increase of elastic modulus of non-vulcanized blends, indicating effective interaction between the blend components. The solvent uptake experiments suggest a co-vulcanization process in blends compatibilized with functionalized EVA.