Thermogravimetric Analysis (TGA)/Differential Thermal Analysis (DTA)

Thermogravimetric analysis (TGA) is a thermal analysis technique which measures the weight change in a material as a function of temperature and time, in a controlled environment. This can be very useful to investigate the thermal stability of a material, or to investigate its behavior in different atmospheres (e.g. inert or oxidizing). It is suitable for use with all types of solid materials, including organic or inorganic materials.
Differential thermal analysis (DTA) is a calorimetric technique, recording the temperature and heat flow associated with thermal transitions in a material. This enables phase transitions to be determined (e.g. melting point, glass transition temperature, crystallization etc.).
Ideal Uses for TGA/DTA Relevant Industries for TGA/DTA
• Thermal stability/degradation investigation of organic or inorganic materials, e.g. polymers, composites, glasses, metals, minerals etc.
• Thermal stability/degradation investigations in inert or oxidative atmospheres, or in vacuum
• Determination of organic/inorganic content of mixtures
• Curing kinetics (e.g, adhesives, polymers)
• Chemical composition measurements (using appropriate reference standards, accurate quantification of sample composition can be determined
• Phase transition measurement (e.g. glass transition, clustering, crystallinity, melting point)
• Quantum - size effect investigation for nanomaterials
• Reaction kinetics with reactive gases (e.g., oxidation, hydrogenation, chlorination, adsorption/desorption)
• Pyrolysis kinetics (e.g., carbonization, sintering) • Semiconductor
• Energy
• Polymers/biomass
• Pharmaceutical
• Biomedical
• Metallurgy
• Ceramics
• Chemicals
• Construction materials
• Optical
• Solar
• Batteries
 
Strengths of TGA/DTA Limitations of TGA/DTA
• Any type of solid can be analyzed, with minimal sample preparation (e.g. powders, pellets, chunks, flakes etc)
• Minimum sample size ( at least 0.1mg)
• Qualitative or quantitative analysis • Solid (or initially solid) samples only
• Data interpretation not always straightforward. Analysis in combination with other techniques is often helpful.

Evans Analytical Group LLC , . (2011). Thermogravimetric analysis (tga)/differential thermal analysis (dta). Retrieved from http://www.eaglabs.com/techniques/analytical_techniques/tga_dta.php


Thermogravimetric Analysis
 
Thermogravimetry thermal analysis (TGA) testing.
Thermogravimetric (TGA) analysis is used for determination of endotherms, exotherms, weight loss on heating or cooling, and more. Materials analyzed by TGA include polymers, plastics, composites, laminates, adhesives, food, coatings, pharmaceuticals, organic materials, rubber, petroleum, chemicals, explosives and biological samples.
TGA materials analysis:
Thermogravimetric analysis uses heat to force reactions and physical changes in materials. TGA provides quantitative measurement of mass change in materials associated with transition and thermal degradation. TGA records change in mass from dehydration, decomposition, and oxidation of a sample with time and temperature. Characteristic thermogravimetric curves are given for specific materials and chemical compounds due to unique sequence from physicochemical reactions occuring over specific temperature ranges and heating rates. These unique characteristics are related to the molecular structure of the sample. When used in combination with FTIR, TGA/FTIR is capable of detailed FTIR analysis of evolved gases produced from the TGA.

TGA thermogravimetric capabilities:
• Compositional analysis of materials
• Decomposition temperatures
• Rate of degradation
• Product lifetimes
• Oxidative stability
• Evaluation of polymer flammabilities
• Thermal stabilities
• Determination of rancidity of edible oils
• Fingerprinting unknown polymers
• Moisture Content
• Volatiles content, VOC analysis
• Analysis of evolved gases using TGA/FTIR
• Competitive product evaluation
• Measurement of oil extender content in elastomers
• Effects of reactive atmospheres on materials
• Determination of inert filler or ash contents
• ASTM D6375 Noack Method
Thermal analysis:
• Thermal Analysis and Testing
• Thermo-Mechanical Analysis
• Thermal Properties Analysis
Intertek Group plc, . (n.d.). Thermogravimetric analysis. Retrieved from http://www.intertek.com/analysis/thermogravimetric/

What is DSC?
 
Differential Scanning Calorimetry (DSC) is unsurpassed for understanding the stability of biological systems. DSC directly measures heat changes that occur in biomolecules during controlled increase or decrease in temperature, making it possible to study materials in their native state
DSC measures the enthalpy (∆H) of unfolding due to heat denaturation. A biomolecule in solution is in equilibrium between the native (folded) conformation and its denatured (unfolded) state. The higher the thermal transition midpoint (Tm), when 50% of the biomolecules are unfolded, the more stable the molecule. DSC is also used to determine the change in heat capacity (ΔCp) of denaturation
Applications include:
• Liquid biopharmaceutical formulations.
• Process development
• Assessment of biocomparability during manufacturing
• Protein stability and folding.
• Assessment of the effects of structural change on a molecule’s stability.
• Characterization of membranes, lipids, nucleic acids and micellar systems
• Antibody domain studies.
• Rank order binding.
MicroCal Inc, . (2008). What is dsc?. Retrieved from http://www.microcal.com/technology/dsc.asp


Another definition
An instrument which measures the rate of heat evolution or absorption of a specimen which is undergoing a programmed temperature change. A recorder prints out the data as a plot of increase in heat per increase in temperature, versus temperature. The instrument has been utilized to study the curing characteristics and related properties of thermosetting resins.

CRC Press LLC, . (1989). Differential scanning calorimeter . Retrieved from http://composite.about.com/library/glossary/d/bldef-d1641.htm

original author: Nat 
help to post: monica