In order to study the effect of shedding speed on the adhesion strength of polymers, Crotochon designed a special instrument called a rolling adhesion Tester (Figure 107).
The main part of this adhesion Tester is a large steel plate 1, on which a cylindrical column 2 is firmly installed, and there are brackets 3 and 4 that can move freely in the middle of the column. An axle is fixed on the support 3, and a table 35 millimeters is arranged on the bearing of axle one end, and the cylinder 5 of diameter 25 millimeters is rotating. On the support 4 there is the same cylinder 6 . The rotation of the cylinder 6 is driven by the motor through the three-stage cone wheel 10 with a belt.
Put one end of the tested paint film 7 coated on the cylinder 5 over the cylinder 6, and fix the tear-off weight 8 on the paint film. Utilize microscope 9 to observe the boundary that is torn off now.
The determination of paint film adhesion can be carried out on any bottom surface; for the sake of cooperation, the cylinder 5 must also be made of suitable materials (steel, glass, etc.).
Before the test, wash the cylinder 5 well, and then apply a paint film on the cylinder by rotating the cylinder in the glass tank containing the sample. The speed of rotation is two revolutions per minute.
After the paint film is dried, it is carefully separated from the surface of the circle, and one end of the paint film is passed over the cylinder 6, and a weight is fixed on the paint film.
The tests were carried out at various pull speeds, varying the speed of rotation of the cylinder from 2 to 120 revolutions per minute.
Because the cylinders 5 and 6 can rotate freely, and the boundary of the paint film falls does not move, so it is convenient to observe in the microscope.
The work done by the falling process can be measured by the weight of the paint film coming off the cylinder 5.
When the paint film is very elastic, in order to prevent the paint film from elongating when it is torn off, a silk material (HA Krotova) can be carefully pasted on the top of the paint film.
As pointed out by Delia and Croto, the roll-in adhesion Tester is very suitable for the study of polymer adhesion.
