Enhanced Tribological Properties of Vulcanized Natural Rubber Composites by Applications of Carbon Nanotube: A Molecular Dynamics Study

Abstract

Tribological properties of tread rubber is a key problem for the safety and durability of large aircraft tires. So, new molecular models of carbon nanotube (CNT) reinforced vulcanized natural rubber (VNR) composites have been developed to study the enhanced tribological properties and reveal the reinforced mechanism. Firstly, the dynamic process of the CNT agglomeration is discussed from the perspectives of fractional free volume (FFV) and binding energy. Then, a combined explanation of mechanical and interfacial properties is given to reveal the CNT-reinforced mechanism of the coefficient of friction (COF). Results indicate that the bulk, shear and Young’s modulus increase with the increasement of CNT, which are increasement of 19.13%, 21.11% and 26.89% in 15 wt.% CNT/VNR composite compared to VNR; the predicted results are consistent with the existing experimental conclusions, which can be used to reveal the CNT-reinforced mechanism of the rubber materials at atomic scale. It can also guide the design of rubber material prescription for aircraft tire. The molecular dynamics study provides a theoretical basis for the design and preparation of high wear resistance of tread rubber materials.

A comparative study on the interfacial characteristics and tensile behaviors of natural rubber composites reinforced by carbon and boron nitride nanotubes

“…A 4.42 nm (5,5) CNT and a 4.5 nm (5,5) BNNT were embedded in the simulation boxes with a size of 5.7 Â 5.7 Â 4.5 nm 3 , separately, considering the polymeric end-cap. [40] Subsequently, the NR molecular chain composed of 50 monomers [28] was packed into the simulation boxes with a density of 0.98 g/cm 3 . After establishing the models, a geometry optimization of the initial models was firstly conducted by using the conjugate gradient approach.…”

“…A shown in Figure 6, the Young's moduli of the neat NR polymer, CNT/NR composites, and BNNT/NR composites are estimated to be 1.88, 2.3, and 2.38 GPa, respectively, which are in a reasonable range compared to the previous study. [27,28] It is indicated that a significant increase of 22.34% and 26.59% in the Young's modulus of the NR composites can be obtained by the incorporation of CNT and BNNT as reinforcements. Moreover, the yield stresses of the NR composites reinforced by the CNT and BNNT are predicted to be 106.71 and 121.99 MPa, which shows an increment of 4.34% and 19.28%, separately, as compared to that of the neat NR matrix (102.27 MPa).…”

“…They found that the EUG/NR composites with a ratio of 30/70 have a higher friction coefficient and mechanical strength. Teng et al [ 28 ] applied MD simulations to study the tribological performances of the vulcanized natural rubber composites reinforced by CNTs. The results revealed that significant increases of 19.13%, 21.11%, and 26.89% in the bulk, shear, and Young's moduli of the composites were respectively achieved by the application of 15 wt% of CNTs.…”

Atomistic Modeling of Mechanical Properties and Creep Behavior of Graphene Oxide Reinforced Natural Rubber Composites

“…Teng et al shown that when CNT content increases, bulk, shear, and Young's modulus increase by 19.13%, 21.11%, and 26.89%, respectively, in a 15 wt% CNT/VNR composite compared with VNR. [18] According to Li et al, the introduction of graphene reinforcements leads in a 150% increase in Young's modulus, a 27.6% increase in shear modulus, and a 35% increase in hardness of polymer composites. Furthermore, the average friction coefficient and wear rate of natural rubber composites have been lowered by ≈35% and 48%, respectively.…”

“…shown that when CNT content increases, bulk, shear, and Young's modulus increase by 19.13%, 21.11%, and 26.89%, respectively, in a 15 wt% CNT/VNR composite compared with VNR. [ 18 ]…”