Effects of thermal oxidative ageing on dynamic viscosity, TG/DTG, DTA and FTIR of SBS- and SBS/sulfur-modified asphalts

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

Use of styrene butadiene rubber industrial waste devulcanized by microwave in rubber composites for automotive application

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

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

Thermal, ozone and gamma ageing of styrene butadiene rubber and poly(ethylene-co-vinyl acetate) blends

Blends of styrene–butadiene rubber (SBR) and poly(ethylene-co-vinyl acetate) (EVA) with different ratios were prepared with a two-roll mixing mill and were vulcanized by three different crosslinking systems, namely, sulfur (S), dicumyl peroxide, and a mixture consisting of S and peroxide (mixed). The vulcanization behavior of the blends was analyzed from the rheographs. The mechanical properties, including stress–strain behavior, tensile strength, elongation at break, modulus, hardness, and abrasion resistance, of the blends were examined. The morphology of the prepared blends was studied with scanning electron microscopy with special reference to the effects of the blend ratio and crosslinking systems. A relatively cocontinuous morphology was observed for the 20/80 SBR/EVA composition. The mechanical properties increased with increasing EVA content up to 60–80%, for all of the vulcanizing modes. The tensile fracture surfaces were analyzed under a scanning electron microscope to understand the failure mechanism. Various theoretical models were applied to explain the properties of the blends. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 827–837, 2004

Effects of the blend ratio and crosslinking systems on the curing behavior, morphology, and mechanical properties of styrene–butadiene rubber/poly(ethylene‐co‐vinyl acetate) blends

The thermal behaviour of styrene butadiene rubber (SBR)/poly (ethylene-co-vinyl acetate) (EVA) blends was studied by using thermogravimetry (TG) and differential scanning calorimetry (DSC). The effects of blend ratio, cross-linking systems and compatibilization on the thermal stability and phase transition of the blends were analyzed. It was found that the mass loss of the blends at any temperature was lower than that of the components, highlighting the advantage of blending SBR and EVA. The addition of compatibilizer was also found to improve the thermal stability. DSC studies indicated the thermodynamic immiscibility of SBR/EVA system even in the presence of the compatibilizer. This is evident from the presence of two different glass transition temperatures, corresponding to SBR and EVA phases in both compatibilized and uncompatibilized blends.

Thermal behaviour of styrene butadiene rubber/poly(ethylene-co-vinyl acetate) blends

The dynamic mechanical behaviour of uncrosslinked and crosslinked styrene butadiene rubber/poly (ethylene-co-vinyl acetate) (SBR/EVA) blends was studied with reference to the effects of blend ratio, crosslinking systems, a compatibilizer viz. maleic-anhydride grafted poly [styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS-g-MA), frequency and temperature. The two separate tan δ peaks, obtained during DMA, indicated the immiscibility of SBR/EVA system. The damping properties increased with SBR content for uncrosslinked and crosslinked blends. In the case of crosslinked systems, depending upon the type of crosslinking agent used, the glass transition temperature (T
 g) of SBR phase has been found to be shifted to higher temperatures. The damping characteristics of the blends were observed to be affected by the variations in frequency. The addition of the compatibilizer improved the storage modulus and reduced the damping properties. These results have been correlated with the morphology of the blends, attested by scanning electron micrographs. The activation energy for glass transition has been computed. The experimental data on storage modulus were compared with theoretical predictions.

C. K. Radhakrishnan

Papers

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

Thermal, ozone and gamma ageing of styrene butadiene rubber and poly(ethylene-co-vinyl acetate) blends

Effects of the blend ratio and crosslinking systems on the curing behavior, morphology, and mechanical properties of styrene–butadiene rubber/poly(ethylene‐co‐vinyl acetate) blends

Thermal behaviour of styrene butadiene rubber/poly(ethylene-co-vinyl acetate) blends

Dynamic mechanical properties of styrene butadiene rubber and poly (ethylene-co-vinyl acetate) blends