How to identify the material and quality of the rubber expansion joints

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How to identify the material and quality of the rubber expansion joints: 1.We can soak the sample which is taken down from the rubber body in the medium.After a certain time and temperature taken weighed according to the rate of change in weight and hardness to determine the type of material.For example, in the 100 degree oil soak 24 hours, fluorine rubber, NBR, CR quality and hardness change rate is very small, while EPDM, NR, SBR increased more than twice of the weight and hardness of the great change, volume increased obviously.

2. Burning method: take a small amount of rubber combustion in air. Fluorine rubber, CR, CSM from the fire extinguishment, even burning flame is usually much smaller than NR, EPDM.

3 .hot air aging test: sampling from products, put it in the box one day aging aging condition analysis after aging. For example, 150 degrees NR, CR, SBR are NBR EPDM and elastic brittle fracture. Up to 180 degrees NBR and 230 degrees will be brittle, HNBR will brittle fracture, fluorine rubber and silica gel still has excellent elasticity.

4.Measuring the proportion of rubber:generally fluorine rubber has the largest share, more than 1.8, CR, ECO were also above 1.3.

5.Low temperature method: sampling from products, the samples soaked in low temperature environment for 2-5 minutes, feeling the hardness change under certain temperature. For example, -50, silicone softer than fluorine rubber.