TST-300 Congo Red Thermal Stability Tester is used to determine the thermal stability of PVC compounds for insulating and sheathing materials of electric cables.

Test principle:

Place about (50±5)mg sample into a specified glass tube. The glass tube is placed into oil bath at the temperature of (200±0.5)℃. A Congo red paper or common PH paper is inserted into the glass tube; its other end is folded and hung on the top wall of glass tube. Record the time during the Congo red paper becomes from red to blue (the common PH paper becomes from PH5 to PH3). The time of color change is expression of the thermal stability.