Wear and frictional performance of betelnut fibre-reinforced polyester composite

Abstract

The current work is an attempt to use betelnut fibres as reinforcement for tribo-polyester composite. The composite was fabricated using hand lay-up technique. It consists of 13 layers of randomly distributed betelnut fibre mats and 15 layers of polyester. Wear and frictional behaviours of the composite were studied against a polished stainless steel counterface using a newly developed block-on-disc machine. Tests were conducted at 2.8 m/s sliding velocity, different applied loads (5-30 N), and sliding distances (0-6.72 km). In addition, the orientation of the fibre mats, with respect to the sliding direction of the counterface, was considered, i.e. anti-parallel (AP-O), parallel (P-O), and normal (N-O). The worn surface morphology was studied using a scanning electron microscope. Optical microscopy was used to observe the wear track surface on the counterface. In addition, the modifications on the counterface roughness were studied. This work revealed that the presence of betelnut fibre in the matrix, namely P-O, enhanced the wear and frictional performance of the polyester by about 98 and 73 per cent. Applied load has less effect on the specific wear rate and friction coefficient of the composite, especially in P-O and AP-O. The composite behaved differently in N-O in which the wear and friction increased when the applied load and sliding distance increased. The composite exhibited higher wear performance in P-O compared with AP-O followed by N-O. In N-O, poor support of the fibres to the resinous was observed, i.e delamination, pullout, and breakage in the fibres. In AP-O, the wear mechanism was predominated by plastic deformation, micro- and macro-cracks in the resinous regions associated with pullout, and breakage of the fibre. In P-O, debonding of fibres was the main wear mechanism.