The investigation of mechanical, thermal and tribological properties of polyamide 6 composite materials

Polyamide 6 fillers with up to 30 wt% short glass fiber and mica, were prepared by extrusion and injection molding machine. Short glass fiber and mica fillers, with weight percentages varying between 10 and 30 wt% as single and as mixed, were added to Polyamide 6 thermoplastic matrix. In this study, dynamic mechanical analysis test, thermal properties such as differential scanning calorimeter test, vicat softening temperature, heat deflection temperature and tribological tests were used to examine the effect of short glass fiber and mica fillers addition on the mechanical behavior of polyamide 6 thermoplastic material. Storage modulus, loss modulus and tan deltha, melting temperature, glass transition temperature, vicat and HDT values, friction coefficient and wear rate values of unfilled polyamide and its composites were obtained. The results showed that the melting and glass transition temperature values increased with increment of glass fiber and mica. Vicat softening temperature values increased with the addition of glass fiber while Vicat softening temperature values decreased with the increase in mica filler. Storage modulus and loss modulus increased with the increment of glass fiber and mica filler while storage modulus and loss modulus decreased with the increase in glass fiber and mica filler. In addition, in this thesis, dry sliding wear characteristics of polyamide and its composites were investigated using a pin-on-disc wear test machine. Three different polymer composite disc materials are used for wear test. Discs are; 30%wt. glass fiber reinforced polyamide 6 composite, 30%wt. mica filled polyamide 6 composite and 6% wax filled polyamide 6 composite. Wear tests were carried out at the sliding speeds of 0.5 m/s and applied loads of 20N, 30N and 40N and under atmospheric conditions of temperature and humidity. Friction coefficient and specific wear rate values for different combinations of the materials were obtained and compared. For all material combinations, it was observed that, the coefficient of friction increases linearly with the increase in applied load values. Furthermore, their specific wear rate slightly increases with the increase in applied loads and sliding speed values. Moreover, wear surface investigations of all polymer composites used were done by using optical microscope.