Enhancement of the Water-Lubricated Tribological Properties of Hybrid PTFE/Nomex Fabric Laminate Composite via Epoxy Resin and Graphite Filler

This paper studied a hybrid polytetrafluoroethylene (PTFE)/Nomex fabric composite with lower friction coefficient (COF) and high underwater wear resistance. A pin-on-disk tribometer was used to test tribological properties under different applied loads and rotation speeds. The wear surface, transfer film and cross-section were analyzed by scanning electron microscope (SEM) and optical microscope. The results showed enhanced underwater tribological properties because of excellent self-lubricating properties of PTFE fibers and a good lubricating effect and load-carrying capacity of graphite fillers. Improved underwater mechanical strength was connected to the high strength of epoxy resin and high bonding force between Nomex and epoxy resin.

Influence of fibre alignments on the mechanical properties of novel Spirograph based non-woven mat composites

Fibre architecture of glass fibre (GF) reinforced polymer composites has a major impact on the mechanical properties for structural applications. In this study, a novel continuous glass fibre non-woven GF mat based on Spirograph art pattern is laid using a customized mechanical system. Spirograph-based continuous glass fibre non-woven (SNW) mat of different patterns was prepared and GF laminate epoxy composites were fabricated with the aim of achieving quasi-isotropic mechanical properties. The samples were cut to dimensions of test specimens from various identical locations symmetrically from a circular-shaped SNW composite laminates which were subjected to flexural, impact, shear and modified compression with anti-buckling tests. One particular SNW pattern composite laminate exhibited 40.82% better impact and 49.01% better shear resistance than commercial 0°/90° woven roving mat composite. The developed SNW laminate composite had quasi-isotropic fibre orientation and better mechanical properties without any stitching and interlacing as in case of woven fibre laminate composite.

Enhancement of out-of-plane mechanical properties of carbon fiber reinforced epoxy resin composite by incorporating the multi-walled carbon nanotubes

In this study, epoxy hybrid nanocomposites reinforced by carbon fibers (CFs) were fabricated by a filament winding. To improve out-of-plane (transverse) mechanical properties, 0.5 and 1.0 Wt.% multi-walled carbon nanotubes (MWCNTs) were embedded into epoxy/CF composites. The MWCNTs were well dispersed into the epoxy resin without using any additives. The transverse mechanical properties of epoxy/MWCNT/CF hybrid nanocomposites were evaluated by the tensile test in the vertical direction to the CFs (90º tensile) and flexural tests. The fracture surfaces of composites were studied by scanning electron microscopy (SEM). The SEM observations showed that the bridging of the MWCNTs is one of the mechanisms of transverse mechanical properties enhancement in the epoxy/MWCNT/CF composites. The results of the 90º tensile test proved that the tensile strength and elongation at break of nanocomposite with 1.0 Wt.% MWCNTs improved up to 53% and 50% in comparison with epoxy/CF laminate composite, respectively. Furthermore, the flexural strength, secant modulus, and elongation of epoxy/1.0 Wt.% MWCNT/CF hybrid nanocomposite increased 15%, 7%, and 9% compared to epoxy/CF laminate composite, respectively.

Optimization of Test Procedure for Simulation of Paper Laminate in Axial Loading Conditions Using FRANC2D and CASCA

In present investigation, an attempt was made to optimise the peak stress for paper laminate composite using FRANC2D software. It was observed that the laminate having the triangular geometry supposed to be most appropriate as it has the lowest value of peak stress contour compared to other models like parallel strip, up-down tapered and down-up tapered. The minimum peak stress was observed for the samples having triangular geometry while the maximum was observed for down-up tapered samples. Therefore, the hypothesis adopted to use in-built materials with variables reinforcement area and strip geometry and length in the FRANC2D software to optimize the sample geometry and then apply it to the paper laminate by considering its mechanical properties might be use to optimize the peak stress of paper laminate composite in tensile loading conditions. It was also observed a length of one-quarter of the length of the plane strip, might be the optimum length of the paper laminate samples. However, it feels that, the above model can be further modified considering a more significant mechanical properties as well as different sample geometries.

Propargyloligosilazane matrixed composite for high temperature material combining polymer and ceramic properties

A new single-phased thermosetting resin (propargyloligosilazane, POSZ) was prepared through Hofmann alkylation of oligosilazane with propargylbromide; the propargyl content in POSZ was controlled by monitoring the amount of propargylbromide in synthesis. The characterizations showed that POSZ has ideal rheology during material processing, the thermal curing temperature could be lowered when isocyanate was used as crosslinking agent, and the thermally cured POSZ can be pyrolyzed into anti-oxidative ceramic at a high yield of >70%. For POSZ-matrixed carbon-fabric laminate composite, it possessed high mechanical properties and retained the original shape with the increase of temperature as high as 800 °C. The POSZ-matrixed laminate has the mechanical properties combining polymer character at room temperature and ceramic character at high temperature, and it will find many prospective high temperature applications in need of polymer and ceramic properties simultaneously.