52 Questions
What are the factors that can affect the mass and temperature measurements in TG?
Sample size and packing, heating rate, type of pan used in the instrument, gas flow (atmosphere the instrument is in), electrostatic effects, condensation and reaction, buoyancy, sample holder, and reaction enthalpy.
How are samples handled in thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC)?
Samples are airtight sealed, and the lid is pierced just before measurements are taken, or stored in ceramic crucibles, and the lid is removed just before the experiments, or stored in sample changers to prevent loss of moisture or absorption of water.
What is the purpose of evolved gas analysis (EGA) in thermal analysis?
EGA is used to study the gas evolved from a heated sample undergoing decomposition/desorption.
What is the main difference between differential thermal analysis (DTA) and differential scanning calorimetry (DSC)?
DTA measures the temperature difference against a reference sample, while DSC measures the difference in heating power needed on a sample.
What does thermomechanical analysis (TMA) measure?
TMA measures changes in the dimension of a material when the temperature changes and when the level of stress on the material changes.
What is the purpose of adding plasticizers to polymers?
Plasticizers modify the properties of amorphous materials (i.e., polymers) by decreasing the glass transition temperature with increasing plasticizer content, making the material more rubbery-elastic.
What is thermal analysis, and what properties of a sample can be monitored during this process?
Thermal analysis is a group of techniques in which a property of the sample is monitored against time or temperature while the temperature of the sample, in a specified atmosphere, is programmed. Properties that can be monitored include mass, volatiles, temperature, heat or heat flux, dimensions, acoustical properties, electrical properties, magnetic properties, optical properties, and radioactive decay.
List some thermoanalytical techniques and their corresponding acronyms.
Examples include Thermogravimetry (TG or TGA), Evolved Gas Analysis (EGA), Differential Thermal Analysis (DTA), Differential Scanning Calorimetry (DSC), Thermodilatometry (TD), Thermomechanical Analysis (TMA), Dynamic Mechanical Analysis (DMA), Thermosonimetry, Thermoacoustimetry, Thermoelectrometry, Thermomagnetometry, and Thermooptometry.
What is the principle behind thermogravimetry (TG), and what is its significance in thermal analysis?
TG determines sample purity, decomposition behavior, and chemical kinetics by measuring the changes in the mass of the sample as a function of temperature or time in a controlled atmosphere.
What are the essential components of a TG instrument?
Essential components include the balance and furnace (thermobalance), sample chamber, and instrument to control data handling.
What is the role of the analytical balance in a TG instrument?
The analytical balance with a sensitivity of 1 microgram is central to the TG instrument.
What types of information can be obtained from thermogravimetry (TG) analysis?
TG determines sample purity, decomposition behavior, and chemical kinetics.
The technique of _______________ is used to analyze the change in mass of a sample as a function of temperature or time.
thermogravimetry
_______________ is a technique used to analyze the volatiles evolved during a thermogravimetric experiment.
Evolved Gas Analysis
Thermoanalytical methods are used to characterize the ______________ properties of materials.
thermal
Thermoanalytical techniques can be used to study the ______________ of polymers.
characterization
DMU stands for a type of ______________ that is used to analyze the thermal properties of materials.
thermoanalytical method
The technique of ______ is used to analyze the gas evolved during thermal decomposition of a sample.
evolved gas analysis
Thermogravimetry (TGA) is a technique used to measure the changes in ______ of a sample as a function of temperature.
mass
Thermoanalytical methods are used to characterize the ______ properties of materials.
thermal
Polymers are often characterized by their ______ properties, which can be measured using thermoanalytical techniques.
thermal
Thermogravimetry (TGA) is a popular technique used to study the ______ of materials, such as polymers and ceramics.
decomposition
Samples are stored in a __________ crucible and lid is removed just before experiment.
ceramic
Evolved gas analysis (EGA) is a method used to study the gas evolved from a heated sample that undergoes __________ or desorption.
decomposition
In EGA, it is possible to detect which gas is evolved using evolved gas detection (EGD) often performed by coupling EGA with __________ (MS).
Mass Spectrometry
Companies such as PerkinElmer, Mettler Tolledo, and SETARAM Instrumentation provide __________ instrumentation.
thermo-analytical
A simultaneous TG-MS-EGA was used to study __________ Oxalate CaC2O4.H2O.
Calcium
Thermal analysis is defined by ______________ as “a group of techniques in which a property of the sample is monitored against time or temperature while the temperature of the sample, in a specified atmosphere, is programmed.”
ICTAC
_______________ is a technique used to analyze the change in mass of a sample as a function of temperature or time.
Thermogravimetry
Evolved gas analysis (_______________) is used to analyze the volatiles evolved during a thermogravimetric experiment.
EGA
Thermoanalytical techniques can be used to study the thermal properties of ______________.
polymers
DMU stands for a type of university that is used to analyze the thermal properties of ______________.
materials
There are three main possibilities to place the ______ relative to the balance and furnace.
sample
Evolved gas analysis: ______ is used to analyze the gas evolved during thermal decomposition of a sample.
EGA
In quasi-isothermal TG, the heating is slowed down when a ______ change begins.
weight
Water/moisture content = (A - D) * 100% => ______ content = (A - D) * 100%.
water
To resolve overlapping thermal reactions, the ______ derivative of Dm vs. T (DTG) curve is calculated.
1st
The area under the ______ curve is proportional to this mass change.
DTG
Evolved gas analysis is used to analyze the ______ during thermal decomposition of a sample.
gas
This variation in mass can be either a ______ of mass or a gain of mass.
loss
Thermoanalytical methods are used to study the ______ properties of materials.
thermal
TG was originally developed by ______ in 1915.
K.Honda
TG determines the ______ of a sample, among other properties.
purity
Thermogravimetry is a technique used to measure the changes in ______ of a sample as a function of temperature.
mass
The technique of ______ is used to analyze the change in mass of a sample as a function of temperature or time.
Thermogravimetry
The decomposition of Calcium Oxalate results in the formation of ______ among other products.
carbon dioxide
The essential components of TG include a ______, thermobalance, furnace, sample chamber, and instrument control/data handling.
balance
Purged gas such as ______ is used in TG instruments.
N2
EGA is a method used to study the ______ evolved from a heated sample.
gas
Thermoanalytical methods are used to characterize the ______ properties of materials.
thermal
Polymers are often characterized by their ______ properties, which can be measured using thermoanalytical techniques.
thermal
Thermoanalytical methods are used to study the ______ of materials, such as polymers and ceramics.
thermal behaviour
Study Notes
Thermoanalytical Methods
- Definition: Thermal analysis is a group of techniques in which a property of the sample is monitored against time or temperature while the temperature of the sample, in a specified atmosphere, is programmed.
Thermogravimetry (TGA)
- Measures the change in mass of a sample as a function of temperature or time in a controlled atmosphere.
- Essential components:
- Balance (thermobalance)
- Furnace
- Sample chamber
- Instrument control and data handling
- Three main possibilities to place the sample relative to the balance and furnace:
- Sample furnace (a)
- Horizontal balance (b)
- Suspended (c)
Applications of TGA
- Drying/water content: measures mass loss due to water evaporation
- Decomposition behavior: measures mass loss or gain due to chemical reactions
- Chemical kinetics: measures the rate of chemical reactions
- Sample purity: measures the mass loss or gain due to impurities
Evolved Gas Analysis (EGA)
- Studies the gas evolved from a heated sample undergoing decomposition or desorption
- Often coupled with techniques such as:
- Mass spectrometry (MS)
- Fourier transform infrared spectroscopy (FTIR)
- Gas chromatography (GC)
Instrument Control and Data Handling
- Modern features:
- PC incorporated into most commercially available instruments
- Heating and cooling cycles controlled by PC
- Data storage and handling
- Resolving overlapping thermal reactions:
- Calculating the 1st derivative of Dm vs.T (DTG) curve
- Using isothermal heating or very slow heating rates
- Quasi-isothermal TG (high resolution or controlled-rate TG)
TG Example: Decomposition of Calcium Oxalate
- Mass loss due to water evaporation and decomposition of calcium oxalate
- Temperature range: 200-900°C
- Gases evolved: H2O, CO, CO2
Companies
- PerkinElmer, USA
- Mettler Toledo, Switzerland
- SETARAM Instrumentation, France
Learn about thermal analysis techniques that monitor various properties of a sample as its temperature changes. Discover the different properties that can be measured, from mass and dimensions to optical and magnetic properties.
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