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Metal free and some metal-perylene polymers as well as some metal phthalocyanine polymers were incorporated into butadiene styrene rubber (SBR) compounds as coloring agents. Ageing and UV resistance of the vulcanizates obtained were studied in terms of the mechanical properties. The dielectric properties of the vulcanizates were also discussed. The results obtained revealed that cobalt perylene and cobalt phthalocyanine polymers showed superior performance in SBR vulcanizates against thermal ageing and UV radiation. The optimum concentration of cobalt phthalocyanine polymer was found to be 1 phr (parts per hundred parts of rubber). [ABSTRACT FROM AUTHOR]

The graft copolymerization of acrylic acid (AA) onto styrene butadiene rubber (SBR) was carried out in toluene at 80°C using benzoyl peroxide (BPO) as initiator. The synthesized styrene butadiene rubber-g-acrylic acid (SBR-g-AA) was characterized with Raman IR spectroscopy. A study was conducted on the use of SBR-g-AA for improving the homogeneity of styrene butadiene rubber/chloroprene rubber (SBR/CR) blend. The SBR-g-AA was incorporated into SBR/CR blend with different blend ratios. The homogeneity of such blends was examined with scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and determination of the dielectric properties. The scanning electron micrographs illustrate improvement of the morphology of SBR/CR rubber blend as a result of the incorporation of SBR-g-AA onto that blend. Also, the dielectric constant (permittivity) and the dielectric loss plots versus the SBR/CR blend ratio show straight lines upon incorporation SBR-g-AA, indicating and confirming the homogeneity of that blend. Physico-mechanical properties of the blend vulcanizates, in presence and absence of SBR-g-AA, were determined, and their thermal stability was evaluated after accelerated thermal aging. The results reveal that SBR/CR (25/75) blend possesses the best thermal stability. Swelling behavior in toluene, in motor oil, and in brake fluid of the blend vulcanizates was also assessed. [ABSTRACT FROM AUTHOR]

The graft copolymerization of acrylonitrile (AN) onto butadiene rubber (BR) was carried out in toluene at 80°C, using dibenzoyl-peroxide (BPO) as initiator. The synthesized poly acrylonitrile-grafted-butadiene rubber (AN-g-BR) was characterized by N% elemental analysis and Fourier-transform infrared (FT-IR) spectroscopy. Styrene butadiene rubber/acrylonitrile butadiene rubber (SBR/NBR) blends were prepared with different blend ratios in presence and absence of AN-g-BR, where the homogeneity of such blends were examined with intrinsic viscosity (?) measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The scanning electron micrographs illustrate disappearance of the macro-scale phase separation of SBR/NBR rubber blend as a result of the incorporation of AN-g-BR into that blend. Viscosity measurements confirm homogeneity of that blend. Differential Scanning Calorimetry traces exhibit shifts in glass transition temperatures ( T g 's) of SBR and NBR in their blend, indicating some degree of homogeneity. Physico-mechanical properties of the rubber blend vulcanizates with different blend ratios, in presence and absence of AN-g-BR, were investigated before and after accelerated thermal aging. The SBR/NBR (25/75) homogeneous blend possessed the best physico-mechanical properties after thermal aging, together with the best swelling behavior in motor oil. The physico-mechanical properties of SBR/NBR (25/75) filled blend with different types of inorganic fillers during thermal aging were studied. [ABSTRACT FROM AUTHOR]

Butadiene-acrylonitrile rubber (NBR) was blended with ethylene- propylene-diene rubber (EPDM) in the presence and absence of different amounts of bromobutyl rubber (BIIR) to be tested as a compatibilizer. The results revealed that 10 phr was the optimum amount of BIIR to get a compatible blend. Dicumyl peroxide (DCP) curing system resulted in EPDM/NBR vulcanizates with better thermal aging resistance than did sulfur vulcanizates. Also DCP produced vulcanizates with the most reduced swelling values both in motor oil and brake fluid. On the other hand, sulfur-curing systems produced EPDM/NBR vulcanizates with much higher mechanical properties than did DCP vulcanizates. The fatigue resistance of the vulcanizates was greatly improved upon blending the two types of rubber. Also, the 25/75 EPDM/NBR blend possessed the highest aged mechanical properties together with good thermal stability. [ABSTRACT FROM AUTHOR]

Ethylene propylene diene monomer rubber (EPDM) was modified with maleic anhydride (MA). Benzoyl peroxide was used as an initiator. Then the produced MA-EPDM was mixed with natural rubber (NR)/EPDM blends with various compositions. The scanning electron micrographs demonstrated that the addition of MA-EPDM (10 phr) improved the compatibility of the NR/EPDM blends and thereby led to a finer phase morphology. The intrinsic viscosity measurements also confirmed the compatibility of that blend. The heat and UV radiation resistance of the NR/EPDM compatibilized blend were determined in terms of physico-mechanical properties of the blends with various blend ratios. The NR/EPDM (25/75) blend showed the best thermal aging resistance. However, the 50/50 blend possessed the best resistance against UV irradiation. The compression recovery study revealed that 25/75 (NR/EPDM) compatibilized blend vulcanizate possessed the highest percent compression recovery at 3, 10, and 18% compressions. The compression of swollen specimens in motor oil indicated that the percent recovery was almost independent of the NR/EPDM blend ratio at high compressions investigated. [ABSTRACT FROM AUTHOR]

The effect of carbon black particle size and structure on the equilibrium volume swelling and elastic recovery of polychloroprene rubber immersed in hydraulic oil and subjected to uniaxial compression stress was investigated in this study. [ABSTRACT FROM PUBLISHER]

The relation between the swelling values of unfilled and carbon black filled polychloroprene rubber, in hydraulic oil, was estimated at the various HAF carbon black concentrations and at various compression strains. The extraction of soluble ingredients from the mixes was related to the swelling values as they were measured from the diffusion curves. [ABSTRACT FROM PUBLISHER]

The effect of carbon black loading concentration on the equilibrium volume swelling and the elastic recovery of polychloroprene rubber immersed in hydraulic oil and subjected to uniaxial compression stress was investigated in this study. [ABSTRACT FROM PUBLISHER]

The effect of vulcanizing agent concentration on the equilibrium volume swelling and the elastic recovery of polychloroprene rubber immersed in hydraulic oil and subjected to uniaxial compression stress was investigated in this work. [ABSTRACT FROM PUBLISHER]