Number: 2007-002-1-100
Title: Guidelines for modulated-temperature
differential scanning calorimetry (MTDSC)
Task Group
Chairman: Jean-Pierre
E. Grolier
Members: Marek
Pyda, Christoph Schick,
Akihiko Toda, and Bernhard
Wunderlich
Objective:
Recommendations on methods of operation and guidelines on standardized
ways of selecting the different parameters of modulation in the use
of modulated-temperature differential scanning calorimeters; including
the multi frequency temperature pulses technique.
Description:
Modulated-temperature differential scanning thermal analysis techniques
are widely used in many fields. Particularly in pharmaceutical, food
and polymer studies where first order transitions, glass transitions
and polymorphism are key issues. All sorts of relaxation phenomena
as well as coupled thermal and kinetic contributions can advantageously
be investigated and selectively studied with such techniques. Produced
commercially by a number of companies, sophisticated instruments are
used by individuals without the required level of knowledge and expertise
necessary to extract the correct information from well established
procedures. Typically, calorimetric measurements are subject to systematic
errors especially when they depend upon the choice of physical parameters
such as amplitude and period of modulation and the temperature scanning
rate. Not only the instrument used plays an important role but the
sample itself to investigate requires the parameters to be tuned to
optimize the response of the instrument in order to eliminate systematic
errors and get full unambiguous information. It has to be recognized
that whatever the instrument used the same information must be obtained
on a given sample.
All thermal analysis techniques where a modulation is
superimposed to the temperature ramp will be reviewed underlying in
each case the basic principles and the derived mathematical description
of the data treatment. The different possible thermal modes (quasi-isothermal,
heat only…) will be considered and the estimation of the corresponding
run parameters established. The different methods of measurement and
calculation of the main thermodynamic quantities, such as specific
heat capacities, first order transitions and glass transitions, will
be carefully analyzed. Particular attention will be paid to the separation
of kinetic effects with emphasis on reversing and non-reversing aspects
of the observed phenomena.
On the different points listed above clear description
should be made of the operating procedures and methodologies. The
project should bring a consistent set of recommendations to be internationally
approved for the use of modulated-temperature calorimetry.
