Title : The potential application of EUG/NR composite with enhanced mechanical and tribological properties in aircraft
Abstract:
The Eucommia ulmoides gum (EUG) is an isomer of natural rubber (NR). The overall properties are enhanced by the unique trans-configuration. According to reported articles, the EUG has excellent miscibility with other polymers, which means the potential application in aircraft in order to satisfy severe working conditions. The whole tire test of aircraft tire is extremely expensive and the results may be affected by unproper production. With the development of computer science, the properties of rubber blends are able to be predicted by molecular dynamics (MD) simulation. Lots of experimental researches proved that the mechanical and tribological properties of EUG/NR composite were enhanced by EUG addition. However, the enhancement mechanism is still remained to be revealed. We propose a more suitable molecular modelling method for the EUG/NR composite, which considering the effects of cross-linking density, bond composition of vulcanization and so on. Suitable size of model is determined for describing the blending system and saving computing power. The results indicate the hardness of the composite increases with the EUG content in the blending system. The young’s and shear modulus show a nonlinear trend with EUG addition. The largest shear modulus and young’s modulo both occur in the 20/80 composite, which are 11.8% and 11% higher than that of NR. The numerical differences between the modulus of the cross- and uncross-linked models reflect the important influence of the cross-linking structure on the overall properties. The results of fractional free volume (FFV) and mean square displacement (MSD) explain the enhancement mechanism of the mechanical properties. Less abrasion is observed in the friction process of EUG/NR composite with high EUG content. The EUG content of the EUG/NR composite is suggested to be no more than 30 phr for the expected overall properties. The results of MD simulation are well trendily matched with the experimental results. Although the huge time and space scale gap between the experiment and simulation makes it impossible to compare results numerically, the results of the MD simulation can provide us a view from nanoscale for the prescription design of rubber composite in aircraft tire application.
Audience take-away:
- The modelling method is suitable for other polymers with cross-linked structure. The results are more accurate than the simple blending system.
- The analysis idea of our work can be adopted and combined with experimental studies for multi-scale research of material design.
- The great overall properties and wide potential application of EUG may inspire others for the R&D of green tire and rubber products.
