Goodrich Flexometer Test

It can be concluded from this study that Perkalink 900 can be used as a cross-linker in XllR and could provide the additional advantages such as, better high-temperature compression set and lower heat built up in Goodrich Flexometer test over HVA-2. 

The important vulcanizate properties demanded by this application, low heat buildup, and low dynamic set have been determined in the Goodrich Flexometer test. The compound containing the antireversion agent exhibits a marked decrease in heat buildup and dynamic permanent set (Figures 14.21 and 14.22). 

As would be expected, the mercaptosilane increases the modulus and tensile to values comparable to those of the carbon black compound. In the Goodrich flexometer test, the heat buildup, which is known to be a rather severe problem, is 27°C, which is well below the value obtained with caibon black. The mercaptosilane also improves the compression set and the Pico Abrasion Index. Significantly, the Road Wear Index was improved to give equivalency to the carbon black compound. 

The Goodrich Flexometer is used for heat buildup testing (ASTM D-623). A cylindrical test specimen is alternately compressed and then released in rapid cycles for a specified period of time. The temperature rise within the test specimen is recorded. Additional data obtained are permanent set and static compression. The Goodrich Flexometer Test is sometimes called the Compression Fatigue Test, because the test specimen is fatigued, or weakened, by the rapidly cycling compression stress. 

FIGURE 14.24 Goodrich flexometer blowout at 100°C (load 216 N, stroke 4.45 mm, frequency 30 Hz, test time 60 ). 

A servo hydraulic dynamic fatigue machine can, clearly, be used for testing under constant strain as well as constant stress conditions and this would be preferable to the traditional mechanical instruments. Interestingly, a comparison has been made of dynamic mechanical properties measured on a new version of the Goodrich flexometer and a servo hydraulic tester48. 

The principles of flexometer testing are described in ISO 4661/1 (BS903, Part A49). The best known test machine is the Goodrich compression flexometer described in ISO 4661-2. (BS903 A40 and ASTM D623). An alternative is the rotary flexometer of ISO 4661 2 a specific example, the Firestone flexometer, is specified in ASTM D623. 

Goodrich Flexometer heat build up at 100 °C after 30 minutes - tests on conveyor belt cover compounds... 

Goodrich Flexometer Dynamic Permanent Set at 100 °C after 120 minutes - tests on NBR oil seal formulations... 

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