The effects of carbon blacks on vulcanization and mechanical properties of filled ethylene-propylene-diene rub- ber (EPDM) are investigated, by comparing with five types of rubber-grade carbon blacks. Curing kinetics is studied by rheometer and the results indicate that the curing characteristics are influenced by combination of surface area of carbon black and sulphur content on the filler surface, because the former one enhances the physical cross-linking and the latter one introduces the additional chemical cross-linking. Both the degree of cross-linking and cure rate increase with increas- ing surface area and sulphur content, whereas the optimum cure time and scorch time decrease. The reinforcing nature of the carbon black is assessed from mechanical measurements. It is suggested that the surface area of carbon blacks strongly affects the physical properties of EPDM/carbon black composites. Conductive carbon black (N472) can be used as desir- able reinforcing filler due to the higher degree of cross-linking of EPDM with N472 than other EPDM/carbon black com- posites. The morphology and distribution of particles are studied by using scanning electron microscope. The sound reinforcing ability of N472 is also supported by scanning electron microscope due to the notable dispersibility of N472 within EPDM matrix. N472 ensures the EPDM/N472 composite the most conductive sample among the five composites.

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Effects of carbon blacks with various structures on vulcanization and reinforcement of filled ethylene-propylene-diene rubber

Effect of different curing systems on the mechanical and physico-chemical properties of acrylonitrile butadiene rubber vulcanizates

Halloysite nanotubes (HNTs) with hollow nanotubular structures were used as a new type of filler for ethylene propylene diene monomer (EPDM) matrix. EPDM/HNT nanocomposites were prepared using a two roll mill by adding 0 to 100 parts per hundred rubber (phr) HNTs. The results show that the tensile properties were increased with the addition of HNTs. The curing time decreased from 0 to 15 phr loading but subsequently increased from 15 to 100 phr, whereas the maximum torque exhibited an increasing trend from 0 to 100 phr. The addition of HNTs reduced the tan δmax and increased the storage modulus especially for the EPDM/HNT nanocomposites at high HNT loading.

The Effect of Halloysite Nanotubes as a Novel Nanofiller on Curing Behaviour, Mechanical and Microstructural Properties of Ethylene Propylene Diene Monomer (EPDM) Nanocomposites

Curing characteristics and mechanical and morphological properties of styrene butadiene rubber/virgin acrylonitrile-butadiene rubber (SBR/vNBR) and styrene butadiene rubber/recycled acrylonitrile-butadiene rubber (SBR/rNBR) were investigated. Results indicated that the curing characteristics, such as scorch time, t2, and cure time, t90, of SBR/vNBR and SBR/rNBR blends decreased with increasing vNBR and rNBR content. At similar blend ratios, particularly up to 15 phr, SBR/rNBR blends exhibited higher t2 and t90 compared with SBR/vNBR blends. Minimum torque (ML) and maximum torque (MH) of SBR/vNBR blends significantly increased with increasing vNBR content. For SBR/rNBR blends, ML increased with increasing rNBR content, but MH exhibited the opposite trend. Tensile strength, elongation at break (Eb), resilience, and fatigue decreased with increasing virgin and recycled NBR content in both blends. Up to 15 phr, the tensile strength, Eb and fatigue life (Kc) of SBR/rNBR blends were higher than in SBR/vNBR blen...

Curing Characteristics and Mechanical and Morphological Properties of Styrene Butadiene Rubber/Virgin Acrylonitrile-Butadiene Rubber (SBR/vNBR) and Styrene Butadiene Rubber/Recycled Acrylonitrile-Butadiene Rubber (SBR/rNBR) Blends

Radiation effect on properties of carbon black filled NBR/EPDM rubber blends

Cure characteristics and mechanical properties of styrene–butadiene rubber/acrylonitrile butadiene rubber

The behaviour of styrene butadiene rubber/acrylonitrile butadiene rubber (SBR/NBR) blends in the environment of chlorinated hydrocarbons, such as carbon tetrachloride, chloroform and dichloromethane, in the temperature range 32–52°C has been investigated. Sulphur, dicumyl peroxide and a mixed system consisting of sulphur and peroxide were used as the vulcanising systems for the matrix. The effects of vulcanising agents, blend composition, solvents and temperature on the sorption characteristics were studied. The sulphur-vulcanised systems exhibited the highest solvent uptake and those with dicumyl peroxide as the vulcanising agent the lowest. This difference has been explained on the basis of the nature of cross links established between the polymer chains during vulcanisation. The solvent uptake increased with an increase in SBR content in the blends when carbon tetrachloride was used as the penetrant, whilst it decreased with SBR content when chloroform and dichloromethane were used as the probes. This behaviour has been explained on the basis of the polarity difference of the solvents. For a given blend system, the solvent uptake was maximum when dichloromethane was used as the solvent and minimum when carbon tetrachloride was used. This has been accounted for in terms of the difference in the size of the penetrants. The intrinsic diffusion coefficient, permeation coefficient, cross link density and interaction parameter were estimated from the sorption data. Thermodynamic parameters such as enthalpy and free energy changes were also calculated. These values indicate that the sorption process in the present systems is exothermic and is more spontaneous in sulphur-vulcanised systems. The experimental results, when compared with different theoretical diffusion models, have been found to be closer to Robeson’s and Maxwell’s models.

K. Habeeb Rahiman

Papers

Cure characteristics and mechanical properties of styrene–butadiene rubber/acrylonitrile butadiene rubber

The Behaviour of Styrene Butadiene Rubber/Acrylonitrile Butadiene Rubber Blends in the Presence of Chlorinated Hydrocarbons