STUDY OF THE FRICTION AND ADHESION OF POLYETHYLENE-TEREPHTHALATE MONOFILAMENTS

The friction and adhesion developed between nominally clean monofilaments of polyethylene-terephthalate in a crossed-cylinder configuration. The adhesion is determined by the free surface energy of the fibres and by the contact geometry. A single region of contact is assumed, this provides a means of estimating the effective geometry of the fibres in the contact zone. From the deduced contact geometry, the area of contact as a function of normal load may be calculated using classical elasticity equations. The friction as a function of normal load may be deduced assuming that it arises primarily from shear of polymer at the interface. The calculated values are in good agreement with friction measurements carried out over a wide range of positive and negative loads. However, the friction experiments at negative loads are best considered as a special case of adhesive failure.