The present study focuses on the development of polymeric friction composites with short carbon fiber, micron and nano-sized fillers, additives with varying weight% in phenol formaldehyde (PF) matrix using hot compression moulding process. The composites prepared with fillers viz. Molybdenum disulfide or Molykote (MK) and multi walled carbon nanotubes (MWCNTs) in carbon fiber reinforced PF matrix is designated as Set-I composites. Inclusion of graphite and nano-clay in carbon fiber reinforced PF matrix is designated as Set-II composites. The prepared composites are tested in Dry sand rubber wheel abrasion wear test rig, following ASTM standards for evaluating the abrasive wear behaviour. From the routine experiments, it was observed that the presence of combined micro and nanofillers i.e. 11.5 wt% MK + 0.5 wt% MWCNTs of Set-I, has shown superior abrasion resistance among the study group. The test results of the Set-I and Set-II composites are analyzed using Taguchi experimental design followed by analysis of variance (ANOVA) to understand the contributions of wear control factors affecting the abrasive wear characteristics. Further, worn surface of selected samples is analyzed using scanning electron micrographs.

Abstract. Mechanical properties of phenol formaldehyde (PF) based hybrid composites reinforced with molybdenum disulphide (molykote; MC), copper (Cu), graphite (Gr) and antimony (Aty) particles in micron size, having different shape and aspect ratio, are studied. Incorporation of MC, Cu and Gr enhanced the hardness, compression and flexural properties of PF based hybrid composites. A slight decrease in density was observed in MC + Gr (A5) reinforced PF based hybrid composites, making these composites suitable in weight susceptible applications. The investigations showed that the control sample A1 without MC/Cu/Gr/antimony (control sample) exhibited poorer mechanical properties. Addition of Cu, MC and Gr to the control sample resulted in moderate improvement in the mechanical properties. However, hybridization of the control sample with Gr + Aty (A6) showed lower mechanical properties compared to that of composites filled with MC and Gr (A4 and A2) respectively. This decrease was ascribed to the tendency of non-uniform dispersion, deprived bonding of Aty particles as well as poor filler-matrix adhesion. When Aty was replaced with Gr + MC (Sample A5), filler-filler with matrix interaction appears to be increased, resulting in increased strength and modulus. The developed PF based hybrid composites have exhibited improved mechanical properties and these composites with detailed thermal and tribostudies may be recommended for railway braking applications.

Mechanical properties of phenol formaldehyde (PF) based hybrid composites reinforced with molybdenum disulphide (molykote; MC), copper (Cu), graphite (Gr) and antimony (Aty) particles in micron size, having different shape and aspect ratio, are studied. Incorporation of MC, Cu and Gr enhanced the hardness, compression and flexural properties of PF based hybrid composites. A slight decrease in density was observed in MC + Gr (A5) reinforced PF based hybrid composites, making these composites suitable in weight susceptible applications. The investigations showed that the control sample A1 without MC/Cu/Gr/antimony (control sample) exhibited poorer mechanical properties. Addition of Cu, MC and Gr to the control sample resulted in moderate improvement in the mechanical properties. However, hybridization of the control sample with Gr + Aty (A6) showed lower mechanical properties compared to that of composites filled with MC and Gr (A4 and A2) respectively. This decrease was ascribed to the tendency of non-uniform dispersion, deprived bonding of Aty particles as well as poor filler-matrix adhesion. When Aty was replaced with Gr + MC (Sample A5), filler-filler with matrix interaction appears to be increased, resulting in increased strength and modulus. The developed PF based hybrid composites have exhibited improved mechanical properties and these composites with detailed thermal and tribo-studies may be recommended for railway braking applications.