Rheological and Extrudate Behaviour of Natural RubberlLatexReclaim Blends

ABSTRACT: The rheological and extrudate behaviour of natural rubber/latex reclaim blends were evaluated using a capillary viscometer . The study shows that the viscosity of natural rubber decreases marginally on the addition of latex reclaim while the variation of viscosity with shear rate is not affected. The temperature sensitivity of the blends is not affected significantly with the addition of latex reclaim . The extrudates of natural rubber/latex reclaim blends are smooth up to the addition of about 50 wt. percent latex reclaim in filled natural rubber compounds.

Rheological Characteristics of Short Nylon -6 Fiber Reinforced Styrene Butadiene Rubber Containing Epoxy Resin as Bonding Agent

The rheological characteristics of short Nylon-6 fiber-reinforced Styrene Butadiene rubber (SBR) in the presence of epoxy resin-based bonding agent were studied with respect to the effect of shear rate, fiber concentration , and temperature on shear viscosity and die swell using a capillary rheonzeter. All the composites containing bonding agent showed a pseudoplastic nature, which decreased with increasing temperature. Shear viscosity was increased in the presence of fibers. The temperature sensitivity of the SBR matrices was reduced on introduction of fibers. The temperature sensitivity of the melts was found to be lower at higher shear rates. Die swell was reduced in the presence of fibers. Relative viscosity of the composites increased with shear rate. In the presence of epoxy resin bonding agent the temperature sensitivity of the mixes increased. Die swell was larger in the presence of bonding agent.

Rheology of Short Nylon -6 Fiber Reinforced Styrene-Butadiene Rubber

The rheological characteristics of short Nylon-6 fiber reinforced styrene butadiene rubber (SBR) were studied using a capillary rheometer. The study was done with respect to the effect of shear rate, fiber concentration, and temperature on shear viscosity and die swell. All the melts showed pseudoplastic nature, which decreased with increasing temperature. Shear viscosity increased in the presence of fibers. Introduction of fiber reduces the temperature sensitivity of the rubber matrix. A reduction in die swell was found in presence of fibers.

Studies on short Nylon-6 fiber - elastomer composites with epoxy resin as bonding agent

The thesis describes the development and evaluation of epoxy resin as interfacial bonding agent for short Nylon-6 fiber elastomer composites. Epoxy resin is well known for its adhesive property. The potential use of it as interfacial bonding agent in short fiber composite is not explored yet. Three rubbers viz., acrylonitrile butadiene rubber (NBR), Neoprene rubber (CR) and styrene butadiene rubber (SBR) were selected and different fiber loading were tried. The resin concentration was optimized for each fiber loading with respect to cure characteristics and mechanical properties. Rheological characteristics and thermal degradation of the composites containing different fiber loading and different resin concentrations were studied in detail to find the effect of epoxy resin bonding system. The mechanical properties were studied in detail. The short Nylon -6 fiber improved most of the mechanical properties of all the three rubbers. Tensile strength showed a dip at 10 phr fiber loading in the case of CR while it was continuously increased with fiber loading in the case of NBR and SBR. All the composites showed anisotropy in mechanical properties. The epoxy resin is an effective bonding agent for short Nylon -6 fiber reinforced NBR and CR composites. Epoxy resin improved tensile strength, abrasion resistance and modulus of these composites. SEM studies confirmed the improved bonding of fiber and matrix in the presence of epoxy bonding agent. Epoxy resin was not effective as bonding agent in the case of short Nylon fiber- SBR composite. From the rheological studies of the composites with and without bonding agent it was observed that all the composite exhibited pseudoplasticity, which decreased with temperature. At higher shear rates all the mixes showed plug flow. SEM pictures showed that maximum orientation of fibers occured at a shear rate, just before the onset of plug flow. The presence of fiber reduced the temperature sensitivity of the flow at a given shear rate. Die swell was reduced in the presence of fiber. Shear viscosity of the composite was increased in the presence of resin. Die swell was increased in the presence of epoxy resin for composites at all shear rates. The thermal degradation of NBR and SBR composites with and without bonding agent followed single step degradation pattern. Thermal stability of the composites was improved in the presence of bonding agent. The degradation of virgin elastomer and the composites followed first order kinetics.