The present work aims to investigate the influence of pre-triboelectrification on friction coefficient displayed by polymeric materials by sliding of PP on PET at dry sliding. Thin sheets of steel, aluminium (AL) film, carbon fibres (CF), steel textile, copper textile and steel fibres were inserted behind PP to guarantee good distribution of ESC generated from friction on PET sheet. The experiments showed thatPET provided by thin steel sheets displayed the highest friction values followed by steel textiles, CF, copper textiles, steel fibres and aluminium film. When PET surface was rubbed by PA and gained negative ESC, friction coefficient represented relatively lower values than that recorded in the first condition, while PET surface rubbed by PTFE gained positive ESC, followed by extra ESC generated from rubbing with PP gave the highest friction values. ESC generated on the PET surface significantly increased with increasing normal load and slightly increased with increasing the sliding distance. The highest values of ESC were recorded by inserting steel fibres in the back of PET sheet followed by copper textile and steel sheet, while Al film under PET sheet showed no effect on ESC generated on the two sliding surfaces. The same trend was observed for ESC generated from PP and PET when CF and steel textiles were inserted behind PET.
Ali et al. (Sun,) studied this question.