Table of Contents
What is the principle of differential scanning calorimeter?
The basic principle underlying this technique is that when the sample undergoes a physical transformation such as phase transitions, more or less heat will need to flow to it than the reference to maintain both at the same temperature.
What is differential photo calorimetry?
INTRODUCTION. Differential photocalorimetry (DPC) is a new and powerful analytical tool for the characterization of ultraviolet (UV) curable materials.
How DSC is helpful in polymer identification?
Differential scanning calorimetry (DSC) is a technique used to investigate the response of polymers to heating. DSC can be used to study the melting of a crystalline polymer or the glass transition. The DSC set-up is composed of a measurement chamber and a computer. Two pans are heated in the measurement chamber.
What is differential scanning calorimetry PDF?
Differential scanning calorimetry (DSC) is a technique for measuring the energy necessary to establish a nearly zero temperature difference between a substance and an inert reference ma- terial, as the two specimens are subjected to identical temperature regimes in an environment heated or cooled at a controlled rate.
How does differential thermal analysis work?
Definitions of Differential Thermal Analysis (DTA) A technique in which the difference in temperature between the sample and a reference material is monitored against time or temperature while the temperature of the sample, in a specified atmosphere, is programmed. This is definition of DTA by ICTAC.
How does DSC determine crystallinity?
Polymer crystallinity can be determined with DSC by quantifying the heat associated with melting (fusion) of the polymer. This heat is reported as Percent Crystallinity by normalizing the observed heat of fusion to that of a 100 % crystalline sample of the same polymer.
How does a power compensation DSC work?
For power compensated DSC, the height of the curve at some particular time t is a measure of the heat evolving from the sample per unit time, dH /dt (this also applies to heat flux DSC, after suitable calibration). For either DTA or DSC, one can assume that ∆T is proportional to dx/dt or dH /dt to dx/dt, respectively.
What is the difference between differential thermal analysis and differential scanning calorimetry?
Differential thermal analysis (DTA) is suited for the determination of characteristic temperatures, while differential scanning calorimetry (DSC) additionally allows for the determination of caloric values such as the heat of fusion or heat of crystallisation.
What reference material is used in DTA?
In DTA is usually used alumina (Al2O3), carborundum(SiC) or magnesium oxide(MgO) powder as the reference material for the analysis of inorganic compounds.
What is the degree of crystallinity?
The fraction of the ordered molecules in polymer is characterized by the degree of crystallinity, which typically ranges between 10% and 80%. Higher values are only achieved in materials having small molecules, which are usually brittle, or in samples stored for long time at temperatures just under the melting point.
What is integral in DSC?
In order to integrate a DSC curve (i.e. the rate of heat change (power) as a function of temperature or time) and thus to determine heats of transition etc., it is necessary to establish a baseline to bound the area which is to be integrated.
What kind of reference material is used in DTA?
What is the difference between DSC and DTA thermograms?
TGA measures weight change of a sample over a temperature range, DSC measures heat flow of a sample over a temperature range, and DTA measures heat differences between a reference sample and a sample of interest over a temperature range.