1. Objectives
a)To understand the operating principles of DSC
b)T learn how to analyze degradation steps in materials
c)To edintify weight changes in polymer materials
d)To determine the glass transition and melting point in polymers
Introduction
Thermal Analysis is a branch of materials science,where the properties of materials are studied as they
change with temperature. Several methods are commonly used like ThermoGravimetric
Analysis(TGA),Differential Thermal Analysis(DTA),Differential Scanning Calorimetry(DSC) and
etc.In this experiment we will use PMMA as a sample and DSC.
Equipments
a)Polymethylmethacrylate(PMMA)
b)DSC machine
Methods/Procedures
a)The DSC is calibrated using standards available with the instruments
b)The PMMA is placed to the aluminium pan
c)DSC then is performed from 30 degree celcius to 250 degree celcius in 15deg/min.
Discussion
A DSC analyser measures the energy changes that occur as a sample is heated, cooled or
held isothermally, together with the temperature at which these changes occur.
The energy changes enable the user to find and measure the transitions that occur in the
sample quantitatively, and to note the temperature where they occur, and so to characterise a
material for melting processes, measurement of glass transitions and a range of more complex
events. One of the big advantages of DSC is that samples are very easily encapsulated, usually
with little or no preparation, ready to be placed in the DSC, so that measurements can be
quickly and easily made .Fro the curve we obtained,we can actually determine the glass transition of
PMMA,crystallization and also melting temperature for PMMA.Glass Transition is a method to
characterize a property of a polymeric material. The glass transition is the temperature where the

2. polymer goes from a hard, glass like state to a rubber like state ,here in PMMA,the glass
temperature(Tg ) is about 105 °C.Melting and crystallization exhibit endothermic and exothermic peaks
.The Crystallization ,Tc is about 135 °C degree celcius and the melting temperature ,Tm is about
160°C.The Tg is always lower than Tm.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 .The main property that is measured by DSC is
heat flow, the flow of energy into or out of the sample as a function of temperature or time, and usually
shown in units of mW on the y axis .Thermal events in the sample thus appear as deviations from the
DSC baseline in either an endhothermic or exothermic directions,depending upon whether more or less
energy has to be supplied to the sample relative to the reference materials.Thermogravimetric analysis
(TGA) is an experimental technique in which the weight or, strictly speaking, the mass of a sample is
measured as a function of sample temperature or time. The sample is typically heated at a constant
heating rate (so-called dynamic measurement) or held at a constant temperature (isothermal
measurement), but may also be subjected to non-linear temperature programs such as those used in
sample controlled TGA experiments. The choice of temperature program will depend upon the type of
information required about the sample. Additionally, the atmosphere used in the
TGA experiment plays an important role and can be reactive, oxidising or inert. Changes in the
atmosphere during a measurement may also be made .The results of a TGA measurement are usually
displayed as a TGA curve in which mass or per cent mass is plotted against temperature and/or time .
Suggestion/Recommendation
1)Try to use others sample like Polyethylene terepthalate(PET) and Polypropylene(isotactic) so that we
can practice readings tge Tg.
2)Try to set up with another rate so that we can see the differences between them
Conclusion
The experiment is achieved succesfully because we are now understand the principles of DSC,also able
to analyze degradation steps in materials,identify the weight changes in polymer materials(TGA) and
able to determine the glass transition and melting point of polymers.
Referances
1)Principles and Applications of Thermal Analysis(Paul Gabbott)
2)Introduction to Thermal Analysis Techniques and Applications second edition(Michael E.Brown)
3)Materials Characterization Introduction to Microscopic and Spectroscopic Methods(Yang Leng )
4)Manual Lab III Materials Engineering IIUM