Study on the milling behavior of chloroprene rubber blends with ethylene-propylene-diene monomer rubber, polybutadiene rubber, and natural rubber

The viscoelastic properties of the blends of chloroprene rubber (CR) with ethylene-propylene-diene monomer rubber (EPDM), polybutadiene rubber (BR), and natural rubber (NR) at different temperature were studied using rubber processing analyzer (RPA). Mooney viscosities of compounds were measured and tight milling and sheeting appearance were observed on a two-roll mill. The results showed that Mooney viscosities and the elastic modulus of the blends decreased with the increase of the temperature from 60 to 100 degrees C. And the decreasing trends of pure CR, pure NR, and CR/NR blend compounds were more prominent than that of pure EPDM, pure BR, CR/ EPDM, and CR/BR blend compounds. For CR/EPDM blend compounds, the decreasing trend became slower with the increase of EPDM ratio in the blend. Compared with pure CR, pure NR and CR/NR blend compounds, pure EPDM, pure BR compounds, and the blend compounds of CR/EPDM and CR/BR showed less sensibility to temperature and they were less sticky to the metal surface of rolls and could be kept in elastic state at higher temperature, easy to be milled up and sheeted. At the same blend ratio and temperature, the property of tight milling of the blends decreased in the sequence of CR/ EPDM, CR/BR, and CR/NR. With the increase of EPDM, BR, or NR ratio in CR blends, its property of tight milling was improved.