Tribological and mechanical performances of newly developed eco-epoxy composites incorporating flax fibres and graphene nanoplatelets

Abstract

The inclusion of both fibre and solid lubricants into polymers may provide a potential solution to maximise their tribological and mechanical performances. This study investigates the effect of incorporating flax fibres and graphene nanoplatelets (GNPs) reinformcements in epoxy matrix composites on their tensile, microhardness and adhesive wear behaviour. Dry adhesive wear experiments were conducted using a block-on-ring (BOR) test rig against a stainless steel ring. Adhesive wear performance was evaluated considering the effect of the volume fraction ( V f) of flax fibre (0, 15, 20 and 25 V f .%) and different weight fractions of GNPs (1.5 and 3 wt.%). Different applied loads in the 15–60 N range, covering the mild and severe wear regions, were used. The worn surfaces were examined using a scanning electron microscope (SEM). The results revealed that flax fibre potently improved the stiffness and tensile strength of epoxy. Increase in V f of flax fibre showed a positive tendency to improve the wear resistance of epoxy; however, with an insignificant change in the coefficient of friction (COF). More interestingly, heat distortion temperature (HDT) was found to be the main key parameter controlling the wear behaviours of the composites. SEM observations indicated that severe wear signs – including detachment, fragmentation and fibre debonding – were noted when the interface temperature reached the heat distortion temperature of the epoxy. On the other hand, the inclusion of GNPs reduced the interface temperature during sliding as well as the COF of the flax/epoxy composite. Ultimately, incorporation of flax fibres and GNPs enhanced both mechanical and tribological performances of the eco-composites.

Finite element analysis and experimental validation of polymer–metal contacts in block-on-ring configuration

“…The stress values increased significantly after 30 N, evidenced by the increase in the wear coefficient value, as reported in Table 3. Therefore, it was considered that the mild-to-severe wear transition took place when the applied load exceeded 30 N. Similar findings was observed by the authors in a previous studies [23,24]. However, it can be noticed that the average mechanical stresses (Von-mises and shear stresses) increased by only around 25% at 60 N as compared to that in the mild region, i.e., 30 N (100% increase in the applied load) (see Fig.…”

“…These materials were provided by ATL Composites Pty., Ltd., Australia. Epoxy resin was selected due to its widely usage as a base matrix for polymer composites under wear conditions [22][23][24]. It is also used in composite forms as a load-bearing material, such as composite brakes in automobiles [25].…”

“…The pressure values were determined based on the calculated contact area by using FEM. The sliding speed was fixed at 2 m/s for all tests while the applied load ranged from 15 to 60 N. These values were selected to cover both mild and severe wear regions, where PV fluctuates between 0.33 and 3.9 MPa•m•s -1 [23,24]. The tests were carried out at room temperature ~20 °C.…”

Effects of Adding Graphite to Epoxy Resin on its Mechanical Properties and Mild-to-Severe Wear Performance at its Heat Distortion Temperature

“…However, in wear processes, the thermal energy generated at the interface, where rubbing occurs, has a substantial influence on the wear characteristics of the polymers. The generated frictional heat expedites the wear rate when the interface temperature (IFT) exceeds the specific polymer's temperatures, such as heat distortion temperature (HDT) and glass transition temperature (Tg) [9][10][11]. Due to this factor, the performance of most solid lubricants is restricted to polymer-specific temperatures.…”

Numerical and Experimental Analyses of Hybrid Composites Made from Amazonian Natural Fibers

“…Several advantages, such as excellent thermal and mechanical properties, easy processability, and low production costs, make epoxy resin thermosets suitable for a wide range of applications. Following their huge commercial production, for applications in, for example, the automotive and aerospace industries, in 2019 the global epoxy market reached 26 billion dollars with an expected increase at a compound annual growth rate of 6.2% from 2020 to 2028 [34][35][36][37]. A computational and experimental analysis is carried out to compare curauá fibers, jute and sisal fibers used in epoxy resin matrix composites for use in industry, determining the most appropriate hybridization effect by establishing the proportions and amounts of each fiber in a hybrid composite with better mechanical properties.…”