Scope:

Thermogravimetric Analysis test by ASTM E1131 includes a general thermo-gravimetry methodology for the calculation of highly volatile matter, medium volatile matter, combustible material, and ash content of compounds. This test determines the weight loss percentage of the sample when it is heated at a constant rate in a proper manner. The weight loss over a given temperature range is an indicator of the sample’s composition, including volatile, inert, and thermal stability indications. The Thermogravimetric (TGA) study allows to identify endotherms, exotherms, heating loss weight, and cooling patterns of different materials. TGA is done for polymers, fibers, composites, laminates, adhesives, foods, coatings, pharmaceuticals, and organic materials.

Test Procedure:

Usually, gas flow rates of N₂ and oxidative O₂ are used to provide suitable environments for the ASTM E1131 test. The test material is placed in the sample holder, and the furnace temperature is raised. The initial weight reading is set to 100%, then the heating program is initiated. The gas environment is prearranged for either an oxidative decomposition (air or oxygen), a thermal decomposition (inert – nitrogen gas), or a thermal-oxidative combination.

Sample size:

10 to 15 milligrams of sample

Data:

A graph is plotted between percent weight loss and temperature. 

TGA materials analysis:

TGA technique uses heat to cause material reactions and physical changes. TGA offers quantitative mass shift measurements of transition-related and thermal-degradation products. TGA tracks change in mass over time and temperature occurred due to dehydration, decomposition, and oxidation of a sample. Characteristics of thermogravimetric curves for certain products and chemical compounds are obtained because of a unique series of physicochemical reactions occurring over certain temperature and heating ranges. The molecular composition of a sample is linked to these special characteristics. Thermogravimetric Analysis / Infra-red spectroscopy (TGA/FTIR) combination is capable of detailed FTIR analysis of evolved gases produced from TGA

Conclusion:

Hence, ASTM E1131 is a standard test method for compositional analysis by thermogravimetry.