(1) Graduate School of Engineering, Kogakuin University - Tokyo - Japan, (2) Kogakuin University - Tokyo - Japan, (3) Tomas Bata University in Zlin - Zlin - Czech
In recent years, laser surface texturing using femtosecond laser has been a great attention due to its versatility and precision for surface texturing technique in order to control the tribological properties of various engineering materials. In our previous works, we investigated the fabrication of microstructured surface of various polymeric materials and their frictional properties, and also the frictional properties of the polymeric materials against surface microstructures on the metal counterpart fabricated by femtosecond laser. Most polymeric materials are derived from non-renewable petroleum supply resources, therefore there is a demand to replace them to biopolymer such as plants-derived polymer because of the problems of uncertainty of the petroleum supply and global warming. The purpose of this study is to investigate the frictional properties of the plants-derived polymeric materials against microstructures on the metal counterpart fabricated by femtosecond laser in order to control the tribological properties of polymeric materials. This study discusses the frictional properties in terms of various factors: microstructure pattern, sliding direction, sliding speed and so on. The material used in this study was plants-derived polyamide (PA). Plants-derived PA was extruded by a twin screw extruder and injection-molded. Surface microstructures on SUS304 were fabricated by femtosecond laser. This SUS304 with microstructures using femtosecond laser was used as counterparts. Tribological properties were measured by a pin-on-plate type reciprocating-sliding wear tester under oil lubrication conditions. It was found that the frictional coefficients of plants-derived PA against microstructures on SUS304 are lower than those of non-textured SUS304. This is attributed that the surface microstructure on the metal counterpart fabricated by femtosecond laser plays an important role to control the tribological properties of polymeric materials.