Search

More or less universally, bis(3-triethoxysilyl propyl) tetrasulfide (TESPT) has been used as a coupling agent during dispersion of silica filler in a virgin nonpolar rubber compound. It is for the first time that TESPT has been used as a devulcanizing agent and as-grown devulcanized rubber facilitates the silica dispersion in nonpolar rubber compound without any coupling agent. Dual functionalities of TESPT have been modeled and validated in this work. Various factors like the role of sol-gel content, inherent viscosity of sol rubber, crosslink density, and degree of devulcanization were investigated as a function of devulcanization time and amount of TESPT to optimize devulcanization time and TESPT amount. To study the silica reinforcement, revulcanization of devulcanized SBR was carried out with silica filler and the curing characteristics of the material were evaluated. From the mechanical properties and thermogravimetry analysis the optimum time for devulcanization is determined. Further, scanning electron microscopy (SEM) studies were undertaken to check the coherency and homogeneity of the material., INTRODUCTION Generally, the demand of styrene butadiene rubber (SBR) in tyre industries increases manifold primarily for less C[O.sub.2] emission since SBR offers low rolling resistance and hence accounts for low [...]

In this investigation, incorporation of silica into natural rubber (NR)-reclaim rubber (RR) blend system was carried out by sol-gel technique at various sol-gel reaction temperatures. The effect of RR on silica reinforcement, hitherto unexplored, was studied for different NR/RR blend systems. The degree of reinforcement of sol-gel vulcanizates by equilibrium swelling method indicates that the reinforcing efficiency of the in situ generated silica by sol-gel technique increases with increasing reclaim rubber content. The reinforcing efficiency, tensile properties and thermal stability of sol gel vulcanizates (SGV) prepared at 50°C become maxima as compared to SGV prepared at 30°C and 70°C. The amount of silica incorporated by sol-gel technique was determined by thermogravimetry analysis. It indicates that the thermal stability increases with silica content. Attenuated total reflection study indicates that RR forms bond with silica particles due to the presence of active functional site on RR. Scanning electron microscopy studies further indicate the coherency and homogeneity in the silica filled NR/RR vulcanizates. The microwave diagnosis of different SGVs was also carried out and the frequency dependence of dielectric permittivity (E') and loss (E') were measured. POLYM. ENG. SCI., 53:227-237, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION Reinforcement of elastomeric compounds, defined as the simultaneous enhancement of the elastic modulus and the elongation at break, by addition of particulate filler, is probably one of the most [...]

Mechanochemically devulcanized ground rubber tire (GRT) was (re)vulcanized in compositions with virgin natural rubber (NR). The NR/GRT (re)vulcanizates with GRT content from 20 to 60 wt% have been prepared and studied. Reclaiming of GRT was successfully carried out by tetra methyl thiuram disulfide (TMTD) in presence of spindle oil at around ambient temperature. The cure characteristics and mechanical properties of the virgin NR/reclaim GRT blend were studied. The optimum cure time decreases but scorch time remain unaltered with increasing reclaim rubber content in the blend. Effect of carbon black was studied in NR/RR (80/20) blend. Ageing characteristics of different NR/RR blends were evaluated. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the NR/RR vulcanizate. The dynamic mechanical properties and swelling behavior of NR/RR blend vulcanizates were examined. The elastic and storage modulus of the NR/RR vulcanizates become improve with increasing reclaim rubber content. Electrical properties of NR/RR vulcanizates were also studied. POLYM. ENG. SCI., 47:1091-1100, 2007. © 2007 Society of Plastics Engineers, INTRODUCTION In the twenty-first century, recycling of waste materials is of growing importance for all the industries in the world. The automotive and transportation industries are the biggest consumers of [...]