Influence of viscoelasticity on friction coefficient of abrasive wear for filler-dispersed polyamide 6

The friction and wear properties of polyamide 6 dispersed with titanium carbide particles, aluminum borate whiskers and vapor-grown carbon fibers have been investigated in relation with the filler type, the filler content, the roughness of abrasive paper and the sliding velocity. The results have been analyzed based on an abrasive wear model using an expression μ=(gσs)/(kH) where μ is the friction coefficient, g is the shape factor of the abrasive particle, σs is the stress required for sliding the abrasive particle, k=1.08 and H is the microhardness. The PA6 and the composite films showed abrasive wear except for the ABW/PA6 and TCP/PA6 films worn with a fine abrasive paper which showed adhesive wear. For abrasive wear, the decrease in the roughness of abrasive paper and the increase in the sliding velocity both increased the storage modulus due to viscoelasticity. This led to the decrease in the penetration depth and g. As a result, the friction coefficient of the PA6 and the composite films decreased. On the other hand, the filler type and the filler content influenced the friction coefficient through the changes in σs and H.