Degradation during Mixing of Silica-Reinforced Natural Rubber Compounds.

The optimal mixing conditions for silica-filled NR compounds dictate the need to proceed at a high temperature, i.e., 150 °C, to achieve a sufficient degree of silanization.

Dynamic Response and Molecular Chain Modifications Associated with Degradation during Mixing of Silica-Reinforced Natural Rubber Compounds.

Mixing silica-reinforced rubber for tire tread compounds involves high shear forces and temperatures to obtain a sufficient degree of silanization. Natural Rubber (NR) is sensitive to mastication and chemical reactions, and thus, silica-NR mixing encounters both mechanical and thermal degradation. The present work investigates the degradation phenomena during the mixing of silica-reinforced NR compounds in-depth.

Best Practice for De-Vulcanization of Waste Passenger Car Tire Rubber Granulate Using 2-2-dibenzamidodiphenyldisulfide as De-Vulcanization Agent in a Twin-Screw Extruder.

De-vulcanization of rubber has been shown to be a viable process to reuse this valuable material. The purpose of the de-vulcanization is to release the crosslinked nature of the highly elastic tire rubber granulate. For present day passenger car tires containing the synthetic rubbers Styrene-Butadiene Rubber (SBR) and Butadiene Rubber (BR) and a high amount of silica as reinforcing filler, producing high quality devulcanizate is a major challenge.

The Effect of Silanization Temperature and Time on the Marching Modulus of Silica-Filled Tire Tread Compounds.

Marching modulus phenomena are often observed in silica-reinforced solution styrene-butadiene rubber/butadiene rubber (S-SBR/BR) tire tread compounds. When such a situation happens, it is difficult to determine the optimum curing time, and as a consequence the physical properties of the rubber vulcanizates may vary. Previous studies have demonstrated that the curing behavior of silica compounds is related to the degree of silanization.

A Novel Approach of Promoting Adhesion of Reinforcing Cord to Elastomers by Plasma Polymerization.

Adhesion of cords to elastomers is crucial for many elastomeric products, such as tires and V-belts. The best adhesion system so far is based on a combination of resorcinol, formaldehyde, and a latex (RFL). However, this cord treatment has serious disadvantages in terms of processing and toxicity.

Implications of the Use of Silica as Active Filler in Passenger Car Tire Compounds on Their Recycling Options.

Tires are an important vehicle component, as car handling, safety and fuel economy depend for a major part on the tire composition and construction. As a consequence, tires are improved continuously. The most prominent improvement in the recent past was the use of a silica-silane filler system in passenger car tread compounds, instead of traditionally used carbon black.

Upscaling of a Batch De-Vulcanization Process for Ground Car Tire Rubber to a Continuous Process in a Twin Screw Extruder.

As a means to decrease the amount of waste tires and to re-use tire rubber for new tires, devulcanization of ground passenger car tires is a promising process. Being an established process for NR and EPDM, earlier work has shown that for ground passenger car tire rubber with a relatively high amount of SBR, a devulcanization process can be formulated, as well. This was proven for a laboratory-scale batch process in an internal mixer, using diphenyl disulfide as the devulcanization aid and powder-sized material.

Liquid chromatography/coordination ion spray-mass spectrometry for the analysis of rubber vulcanization products.

Liquid chromatography/coordination ion spray-mass spectrometry has been used for the identification of reaction products in a model rubber vulcanization process. After LC separation using reversed-phase conditions, AgBF(4) in acetonitrile was added, and strong signals were observed for silica-rubber coupling agents and products of the reaction between these and alkenes. The method performs best for substances containing sulfur chains with chain lengths between two and eight sulfur atoms, but sulfur-free compounds containing triethoxysilyl groups were detected as well.