粘着行为中预压紧力和分离速度及相对湿度对分离力影响的实验研究

Experimental Research on Influence of Pre-pressing Force and Separating Velocity and Relative Humidity on Pull-off Force

在改变粘着试验中接触副预压紧力、接触副分离速度以及环境相对湿度的条件下,利用表面力仪实时测量了新鲜解理云母接触副分离过程的分离力,并观察了接触后解理云母接触区的状态.结果表明:在保持弹性接触时,预压紧力对分离力影响不大,接触材料的表面能决定分离力的强度;当预压紧力超过临界值时,接触表面发生塑性变形,在一定范围内分离力随预压紧力的增加而增大;在干接触时分离速度与分离力无直接联系,但在存在大粘度中间层液体时,分离速度的增加可使分离力显著增大;分离力随相对湿度的增加而增大.

Pull-off force of new cleavage mica contact pair was measured simultaneously and respectively in the variable pre-pressing force, separating velocity or relative humidity condition by surface forces apparatus, and the condition of the contact area was observed. Strain gauge was glued onto the cantilever spring, which had been calibrated accurately, at the fixed end, and strain indicator was used to record the strain-time curve. Pull-off force was calculated by contrasting the change of strain between minimal value and steady value to the calibration curve. The pre-pressing force and separating velocity were changed by controlling the feeding distance and velocity of lower sample. Within the elastic contact, the pre-pressing force make no difference on the pull-off force, the surface energy of contact material determines the pull-off force. When the pre-pressing force exceeds the critical point, plastic deformation happens and the pull-off force increases with the pre-pressing force; in dry contact condition, the pulloff force is independent of separating velocity, but when there is any liquid interface layer with large dynamic viscosity, it increase with the separating velocity in contrast; the relative humidity increases the pull-off force.