Development of Liquid Diene Rubber Based Highly Deformable Interactive Fiber-Elastomer Composites

The preparation of intelligent structures for multiple smart applications such as soft-robotics, artificial limbs, etc., is a rapidly evolving research topic. In the present work, the preparation of a functional fabric, and its integration into a soft elastomeric matrix to develop an adaptive fiber-elastomer composite structure, is presented. Functional fabric, with the implementation of the shape memory effect, was combined with liquid polybutadiene rubber by means of a low-temperature vulcanization process. A detailed investigation on the crosslinking behavior of liquid polybutadiene rubber was performed to develop a rubber formulation that is capable of crosslinking liquid rubber at 75 °C, a temperature that is much lower than the phase transformation temperature of SMA wires (90–110 °C). By utilizing the unique low-temperature crosslinking protocol for liquid polybutadiene rubber, soft intelligent structures containing functional fabric were developed. The adaptive structures were successfully activated by Joule heating. The deformation behavior of the smart structures was experimentally demonstrated by reaching a 120 mm bending distance at an activation voltage of 8 V without an additional load, whereas 90 mm, 70 mm, 65 mm, 57 mm bending distances were achieved with attached weights of 5 g, 10 g, 20 g, 30 g, respectively.

Thermal Conductivity of Polybutadiene Rubber from Molecular Dynamics Simulations and Measurements by the Heat Flow Meter Method

Thermal conductivities of polybutadiene rubbers crosslinked by 2.4 and 2.8 phr of sulfur have been found to be functions of temperature via molecular dynamics (MD) simulations using the Green–Kubo method. From an analysis of the heat flux autocorrelation functions, it has been revealed that the dominant means of heat transport in rubbers is governed by deformations of polymeric chains. Thermal conductivities of rubber samples vulcanized by 2.4 and 2.8 phr of sulfur have been measured by the heat flow meter method between 0 ∘C and 60 ∘C at atmospheric pressure. The temperature dependencies of the thermal conductivities of rubbers and their glass transition temperatures derived from MD simulations are in good agreement with the literature and experimental data. Details are discussed in the paper.

LIQUID POLYBUTADIENE EXTENDED ESBR/SILICA WET-MASTERBATCH COMPOSITES FOR IMPROVING ABRASION RESISTANCE AND DYNAMIC PROPERTIES OF TIRE TREAD COMPOUNDS

ABSTRACT Silica wet-masterbatch (WMB) is a well-known technique for manufacturing high-content, highly dispersed silica-filled compounds. Emulsion styrene–butadiene rubber (ESBR)/silica WMB offers several advantages, including excellent silica dispersion and reduced hysteresis, as compared with conventional dry masterbatch (DMB) compound. However, because of the residual emulsifiers in ESBR latex, it can exhibit a decrease in the crosslink density and reductions in its mechanical properties. Moreover, the abrasion resistance cannot be significantly enhanced because of the tradeoff between the improvement in silica dispersion and decrease in crosslink density. Accordingly, the objective of this study was to improve the silica dispersion and abrasion resistance of ESBR/silica WMB compounds by using liquid polybutadiene rubber (LqBR) extended WMB. In detail, three types of LqBR were emulsified to LqBR emulsions, and three types of LqBR extended WMBs were produced by co-coagulating ESBR latex, silane-modified silica, and the LqBR emulsion. A thorough characterization was conducted with emphasis on the silica content, cure characteristics, mechanical properties, abrasion resistance, and dynamic viscoelastic properties. Based on the results, silane-terminated LqBR extended WMB vulcanizate showed a 58% improvement in the 300% modulus, 48% reduced DIN abrasion loss, and a 23% improvement in dynamic properties.

Characterization of Natural Rubber (NR), Polybutadiene Rubber (BR) and Styrene-Butadiene Rubber (SBR) Blends Cured in a Vulcanization System

In this work, the mechanical properties of three types of dough rubber NR, NR/BR, and NR/SBR have been investigated using five percentages of materials fill (30, 40, 50, 60, and 70) pphr. Carbon black was used as a filler material. The tensile test was achieved with 300% elongation and strain rates of (100, 200, 300, 400, and 500) mm/min. The tensile strength results indicate that the maximum value of tensile strength for NR Dough carbon black 60 pphr reaches 23.2 MPa; the maximum tensile strain of NR dough (carbon black 50 pphr) reaches 805.5%, and the modulus of elasticity with carbon black 70 pphr reaches 4.3 MPa. It was found that the compression strength decreases with increasing the carbon black, and the maximum value of compression set at NR dough (carbon black 30 pphr) reaches 29.3%. Fatigue crack growth was achieved according to ASTM D 813 for rubber testing. The minimum value of fatigue strength dough (carbon black 70 pphr) reaches 68 (IRHD). For NR dough (carbon black 30,40,50 pphr) reaches 3.5 mm at the number of cycles 15000 cycle. Finally, the maximum hardness of NR.

MODIFICATION OF POLYBUTADIENE RUBBER: A REVIEW

ABSTRACT Developments in modification of polybutadiene rubber (PBR) using various reagents and catalysts have been reviewed. Hydrogenation and functionalization occurring at the site of unsaturation along chain length are discussed. Hydrogenation involving various metal catalyzed processes is discussed. Suitable conditions that are effective during hydrogenation and functionalization are mentioned in this article. Reactivity ratios associated with microstructures of polybutadiene rubber and possible mechanisms involved are described in the review. The importance of reaction conditions during reactivity and their impact on product properties are highlighted. A specific method that needs to be adopted in order to achieve expected product properties is discussed. Various industrial applications of modified PBR and their commercial products in the global market are discussed.

Understanding the Coupling Effect between Lignin and Polybutadiene Elastomer

From an environmental and economic viewpoint, it is a win–win strategy to use materials obtained from renewable resources for the production of high-performance elastomer composites. Lignin, being a renewable biomass, was employed as a functional filler material to obtain an elastomer composite with a higher degree of mechanical performance. In the presence of a suitable coupling agent, an elevated temperature was preferred for the reactive mixing of lignin with polybutadiene rubber (BR). It is quite fascinating that the mechanical performance of this composite was comparable with carbon black-filled composites. The extraordinary reinforcing behavior of lignin in the BR matrix was understood by an available model of rubber reinforcement. In rubber composite preparation, the interfacial interaction between polybutadiene rubber and lignin in the presence of a coupling agent enabled the efficient dispersion of lignin into the rubber matrix, which is responsible for the excellent mechanical properties of the rubber composites. The rubber composites thus obtained may lead to the development of a sustainable and cost-effective end product with reliable performance. This novel approach could be implemented in other type of elastomeric materials, enabling a genuine pathway toward a sustainable globe.