Abstract Tire wear presents a significant sustainability challenge, contributing to material loss and worn particle emissions. While surface roughness is known to influence wear behavior of materials, its effects in the context of experimental fatigue wear of tire tread compounds has received limited attention. This study examines the impact of abrader surface roughness on wear rate, worn particle characteristics, and wear patterns using the Akron abrader with four grit sizes (24, 36, 46, and 60) under controlled conditions. Three tire tread compounds with distinct wear behavior, a silica-filled passenger green-tire tread and two carbon black-filled truck tire treads, were utilized for this study. Abrader surface topography was characterized using a laser profilometer, and worn particle size and wear pattern were analyzed by digital optical microscopy combined with image processing. It was shown that the average equivalent particle diameter increases monotonically with the surface roughness. However, the wear rate went through a minimum at about Ra ≈ 6.7 μm for all three rubbers under the tested condition. High rate of wear on smooth abraders was attributed to the large number of small particles, which was supported by the analysis of the wear pattern and explained by the fracture-mechanics framework.
ABSTRACT Flue gas desulfurization ash (FGDA), a typical industrial solid byproduct from coal-fired power plants, has significant environmental and economic implications for its resource utilization. However, FGDA contains chemically unstable calcium sulfite (CaSO 3 ·0.5H 2 O), which may affect the structural and performance stability of rubber composites. High-temperature oxidation modification was employed to treat FGDA. By adjusting oxidation temperature, heating rate, holding time, and air volume, the CaSO 3 content was reduced from 43.05% to 1.55% under the selected condition (550 °C, 5 °C min −1 , 40 min, air volume 4.2 L). The modified FGDA (MFGDA) was then evaluated at 15 phr in natural rubber (NR) and epoxidized NR (ENR). Compared with untreated FGDA, MFGDA reduced the reversion percentage at 143 °C from 5.70% to 3.88% in NR and from 10.54% to 7.14% in ENR. In terms of mechanical properties, the archived tensile strengths were 21.99 MPa for NR/MFGDA versus 20.91 MPa for neat NR and 17.31 MPa for ENR/MFGDA versus 14.32 MPa for neat ENR; the ENR/MFGDA elongation at break was 718.68% compared with 623.62% for neat ENR. The oxidation treatment did not improve every cure or mechanical parameter, and the aging response depended on matrix and aging time. Overall, the clearest effects were stabilization of the sulfite-rich ash and lower reversion under the tested conditions. Because complete specimen-level replicate data were not available for the historical ash-filled groups, no statistical superiority or optimum MFGDA loading is claimed.
Abstract The tensile stress-strain data of unfilled samples of four rubber polymers (BR, IIR, NR and EPDM) at 5 different crosslink densities are analyzed. Neglecting finite extensibility effects at 1/λ<0.2 and relaxation of temporary entanglements at 1/λ>0.8, the slope of the Mooney stress curve as a function of the inverse stretch 1/λ in the regime of roughly 0.2<1/λ<0.8 was the same for 3 of the four polymers (BR, IIR and NR) at all crosslink densities investigated, allowing a vertical shift to create Mooney master curves. In the case of EPDM, however, the slope of the Mooney plot increased in proportion to the crosslink density below a specific rubber-type dependent shear modulus , and a vertical shift was only possible above . Motivated by these observations, we present a novel strain-energy function which couples the effects of chain orientation and average chain stretch and fully characterizes the stress-strain behavior by use of a single modulus for rubber samples with equilibrium modulus = ≤ . By adding a phantom chain contribution G c for samples with > , and by accounting for finite extensibility and relaxation of temporary entanglements, a consistent modeling of the tensile stress-strain data of all four rubber polymers is possible. For orthotropic deformations (uniaxial stretch and uniaxial compression) analytical solutions of the new strain-energy function and the corresponding stress-strain relations are presented.
ABSTRACT Graphene and its derivatives, such as graphene oxide and reduced graphene oxide, have attracted considerable attention as effective nanofillers for rubber nanocomposites due to their outstanding mechanical strength, large surface area, and excellent thermal and electrical conductivity. We discuss how graphene-based materials can enhance the performance of elastomers, including natural rubber and various synthetic rubbers, with a particular emphasis on achieving uniform dispersion and strong interfacial interactions within the rubber matrix. We outline key synthesis and functionalization approaches for graphene derivatives, along with commonly used processing methods such as solution mixing, in situ polymerization, latex blending, and mechanical compounding. We further examine how the incorporation of graphene influences cure behavior, rheological characteristics—especially the Payne effect—and the overall structure–property relationships of the composites. Improvements in mechanical strength, thermal stability, electrical conductivity, and barrier performance are discussed in relation to filler dispersion and interfacial bonding. Recent progress in theoretical modeling and simulation is also highlighted, offering insights into predicting composite performance and guiding material design. Despite these advancements, challenges such as large-scale processing, consistent dispersion, and a deeper understanding of interfacial mechanisms remain. Overall, we provide a clear and balanced perspective to support the future development and practical application of graphene/rubber nanocomposites.
Abstract Polymer composites with superior damping performance and thermal buffering property are in great demand for the energy saving applications. In this paper, we report on the successful fabrication of phenyl-silicone rubber (P-SR) composites filled with carbonized organo-vermiculites (CVs), with enhanced damping properties as well as good thermal buffering and heat management capabilities. Results from this study showed that as the CV load is increased, the damping effect is significantly enhanced. The dissipation coefficient (DE) of the composites with 100% CV loadings reached 13.2%, i.e. about ~610% enhancement compared with the neat P-SR. Furthermore, a slight enhancement in thermal effusivity and volumetric heat capacity with CV loadings showed that the high loadings of CV can store more heat energy, and thus prevent the heat energy dissipating in the composites with temperature distributions. The temperature distribution field that was imaged through an infrared thermal imaging technique showed that the composites exhibited excellent thermal inertia performance. Our theoretical analysis also showed that the damping performance and excellent thermal buffering may be ascribed to the strong interfacial interaction between CVs and P-SR matrix. Thus, these composites offer possibilities as thermal buffering materials in various advanced applications that often require materials with easy/scalable processing and damping performance attributes.
