[Thermal] Thermal Gravimetric Analysis (TGA)

TGA (Thermal Gravimetric Analysis) generally refers to a combination of gravimetric and mass-spectrometry analysis. As such, it can be used to detect the presence of chemisorbed gases. This is typically negligible on most carbon adsorbents due to van der Waals repulsion, but it can occur in unique geometries like single-walled carbon nanotubes.

[Thermal] How to Calibrate Differential Scanning Calorimetry (DSC) and Steps

There is potential for slight inaccuracy of measurements in all DSC analysers because sensors, no matter how good, are not actually embedded in the sample, and the sensors themselves are also a potential variable. Therefore, in order to ensure accuracy and repeatability of data, a system must be calibrated and checked under the conditions of use.

[Thermal] Practical Issues of Differential Scanning Calorimetry (DSC) Measurement

This paper discusses sample encapsulation and other key operational points in differential scanning calorimetry (DSC) experiments. The main purpose of encapsulation is to prevent sample contamination of the analyzer and ensure good thermal contact between the sample and the furnace. When selecting sample pans, factors such as temperature range, pressure accumulation, reaction between the pan and the sample, cleanliness, sealing methods for liquid samples, thermal contact between the sample and the pan, and prevention of contamination of the outer wall must be considered.

[Thermal] A Comparative Overview of DSC Designs: Power Compensation, Heat Flux, DTA, and DPC

Describes Differential Scanning Calorimetry (DSC) designs. Power compensation DSC uses two separate furnaces to directly measure energy flow (mW) by maintaining a set heating rate. Heat flux DSC uses a single furnace, measuring temperature differences (△t) between sample and reference, which is then converted to heat flow. Differential Thermal Analysis (DTA) is similar but retains the microvolt signal. Differential Photocalorimetry (DPC) uses UV light to initiate reactions. Pressure cells are also available as accessories. Finally, the text lists ISO standards for DSC methods, covering glass t......

[Thermal] Design and Measuring Principle of Thermogravimetric Analysis (TGA)

Thermogravimetric analysis (TGA) measures sample mass change versus temperature or time using a thermobalance, furnace, gas system, and data acquisition. Key designs include top-loading, hang-down, and horizontal balances. Symmetrical designs compensate for buoyancy effects. Factors like heating rate, sample size, particle size, crucible shape, and gas flow affect results.

[Thermal] Principles of Differential Scanning Calorimetry (DSC) and Types of Measurements Made

Differential scanning calorimetry (DSC) is the most widely used of the thermal techniques available to the analyst and provides a fast and easy to use method of obtaining a wealth of information about a material, whatever the end use envisaged. It has found use in many wide ranging applications including polymers and plastics, foods and pharmaceuticals, glasses and ceramics, proteins and life science materials; in fact virtually any material, allowing the analyst to quickly measure the basic properties of the material.

[Thermal] Application of Fast-Scanning DSC (HyperDSC) to Polymer Analysis

HyperDSC enables fast polymer heating, preventing annealing/recrystallization artifacts. Slow heating alters crystallinity, raising melting points. Fast rates preserve original structure, improve resolution, and accurately measure crystallinity without reorganization. Cooling rate controls crystallization extent. Essential for true material characterization in polymer analysis.

[Thermal] Benefits of Fast Scanning Rates

Fast DSC scanning rates increase sensitivity, allowing small samples and weak transitions to be measured. High rates also prevent annealing and structural changes (e.g., in polypropylene or pharmaceuticals) that distort results during slow heating. Fast scans separate overlapping events, such as moisture loss from glass transitions. Speed improves throughput, but helium purge is recommended for better resolution.

[Thermal] Factors Influencing Thermogravimetric Measurements

Thermogravimetric measurements are affected by multiple factors including heating rate, crucible material, furnace atmosphere, pressure, and sample preparation. Higher heating rates shift reactions to higher temperatures, while open crucibles accelerate gas-phase reactions. Reduced pressure helps separate overlapping mass-loss steps. Inert atmospheres must control residual oxygen. Humidity affects water adsorption studies. Buoyancy and gas flow effects can be corrected via blank curve subtraction. Sample-controlled thermal analysis (SCTA) improves resolution of partial reactions, and automatic......

[Thermal] Pharmaceutical Applications of Fast-Scan DSC: Polymorphism and Amorphous Content

This text describes using Differential Scanning Calorimetry (DSC) to study pharmaceutical polymorphs. Using chlorpropamide as an example, slow heating reveals melting, recrystallization, and a second melt. Fast scan rates can prevent recrystallization, allowing accurate identification of original crystal forms. High scan rates also enhance sensitivity for detecting small glass transitions, enabling quantification of low amorphous content (as low as 1%) in materials like lactose.

[Thermal] What is Thermogravimetric Analysis (TGA)

Thermogravimetric analysis (TGA) measures a sample's mass change as a function of temperature or time under controlled heating programs and atmospheres (reactive, oxidizing, or inert). The technique produces TGA curves and derivative (DTG) curves to reveal physical phenomena (e.g., phase transitions, desorption) and chemical processes (e.g., thermal decomposition, oxidation, reduction). TGA is quantitative, helping determine thermal stability, decomposition behavior, composition, and volatile content. It applies to diverse materials including ceramics, polymers, metals, and composites.

[Thermal] Oscillatory Temperature Profiles

When a cyclic temperature profile is applied to a sample the heat flow signal will oscillate as a result of the temperature program, and the size of the oscillation will be a function of the heat capacity of the sample. Therefore, the amplitude of the heat flow signal allows a heat capacity value to be obtained. This is similar to DMA where the amplitude of the oscillation allows a modulus value to be obtained.

[Thermal] Application to Water-based Solutions and the Effect of Moisture

Fast scanning enables measuring the glass transition of water-based and moist materials by delaying moisture loss and avoiding drying. However, water's thermal lag shifts Tg with scan rate. It's a rapid method to assess stability of plasticized amorphous materials.

[Thermal] Practical Aspects of Scanning at Fast Rates

Outlines key factors for fast scanning DSC: use helium purge gas for better thermal transfer; choose flat-bottom sample pans and avoid contamination; adjust sample size based on the transition (larger for Tg, smaller for melting); select scan rates and optimize instrument settings for high data collection rates.

[Thermal] High-Performance DSC (HyperDSC): Fast Scanning for Accurate Thermal Analysis

Fast DSC scanning (up to 500 °C/min) produces accurate, quantitative data despite traditional concerns about thermal lag. Power compensation systems enable this, with minor calibration adjustments. Short transients allow reliable sub-ambient measurements. Fast cooling also reveals material morphology, as shown in PET studies.