Ash Content Determination Of Vulcanized Rubbers

Importance of Rubber Testing

Vulcanized rubber or rubber products are tested in the laboratories before commencing the process of manufacturing for physical analysis, chemical analysis, and mechanical measuring, etc. Before the manufacturing process, the rubbers are tested to determine various parameters of the material such as moisture volume, melting point, dry mass volume, the percentage of ash and other volatile substances, determination of liquid sample viscosity, the specification of effective substance volume, specifications of heavy metals and rubber toxicants. Determining the ash content in the vulcanized rubbers or synthetic rubbers is an important factor that helps to control the quality of the rubbers. It is done basically to find the component of ash in a material.

Ash Content – A Major Property of Rubbers

For ash determination, a specific amount of rubber sample is taken and kept for combustion inside a testing instrument known as Muffle Furnace. This ash content is quantitatively measured, and percentage of ash content in a material is measured. It is an oven type lab testing machine which is designed to reach high temperatures i.e. maximum up to 900 degrees C, 1200 Degree C or 1400 Degree C. The testing machine is basically used to burn the compounds to determine the percentage of inorganic components in that compound.

Working principle of Muffle Furnaces

The testing instrument “Muffle Furnace” works on the principle of auto-igniting of organic materials due to high temperatures. It is an extremely suitable device which is used for determination of ash content in the vulcanized and synthetic rubbers. The instrument is capable enough to maintain the high temperature as it is insulated with high-quality of fire bricks and imported insulation. The device is manufactured all over the world as per the guidelines of the standards and international standards. It is s true chamber that provides exact heating conditions for accelerated exposures and tests. It is the best testing machine which is used in industries for metal treatment, wool industries, rubber industries and plastic industries for ash determination.

Muffle Furnace by Presto for Ash Determination

Presto Stantest manufacture premium quality of Muffle Furnace to measure the percent of non-volatile substance in a material by heating a material to a certain temperature.

Technical Specification of Presto’s Muffle Furnace

S. No. Technical specification Value
1. Display 16 x 2 alphanumerical LCD Display
3. Tuning Advance Auto-Tune PID temperature controlling with 0.1 degrees C resolution and accuracy.
4. Sensor J Type/K-type sensor as per selection of range
5. Alarm Output is given When the process starts and system stop when the temperature exceeds High Limit/Low Limit
6. LEDs Indications Heating, Timer, Alarm
7. Controls

·         The menu driven system allows the users to set multiple parameters easily·         SSR-based output controls·         RTC (Real Time Control)·         PID parameters settable in menu


9. Timer Timer Set Preset Value up to 99:99 Hours.
10. Temperature Least Count 0.1 degree C
11. Temperature Accuracy ± 5-7 degree C at full range
13. Power Supply 16 Ampere, 220 V, AC single phase
14. Inner Chamber Size 4x4x9, 5x5x10, 6x6x12 and customize size
15. Outer Body Mild Steel Powder Coated


Standard Operating Procedure

  • “Take the weight” of the rubber samples and weight of crucible individually and then together.

Weight Of Sample


  • Following the safety measures and place the crucible inside the machine and close the furnace.
  • Now set the temperature and time of the machine.
  • After that take the weight of the ash and calculate the percentage of ash content in the rubber material.

By following the mentioned operating procedure, the manufacturers can measure the % of ash content in rubbers, plastics, and other polymers easily.