Surface Roughening of Polymers during Plastic Deformation

The surface roughening during tensile and compressive plastic deformations of polymers was investigated with a stylus instrument. The surface roughness of nylon, grey polyvinyl chloride and polyethylene increased with increasing applied strain. The surface roughness of polypropylene and transparent polyvinyl chloride increased in the early stage of tensile deformation, and it remained almost constant in the later stage. Surface roughening was hardly observed for polycarbonate. To investigate the mechanism of surface roughening, the deformed surface was observed by a scanning electron microscope. It was found that the development of fibrous structure, the break of the fibrous structure near the surface and the formation of craze contributed to the surface roughening.