Collected Applications
Thermal Analysis
TUTORIAL KIT
Preface
Modern thermal analysis includes a wide range of very sensitive instrumental techniques. These
techniques allow the accurate measurement of widely different chemical and physical properties.
The METTLER TOLEDO Thermal Analysis Tutorial Kit includes an application booklet and 14
samples with which you can perform typical experiments. The 22 carefully chosen and well-documented applications cover the main areas of thermal analysis and provide an excellent introduction to this very versatile technique.
The Tutorial Kit is designed to encourage you to experiment with the tutorial samples so that
you can discover and become familiar with the possibilities that modern thermal analysis offers.
Several samples have been measured and evaluated with different techniques.
We would like to point out that the evaluation results presented here are typical experimental
results and should not be treated as scientifically guaranteed data. It is quite possible that some
samples undergo slight changes during storage and that the results described here can not be
exactly reproduced. We nevertheless hope that this collection of applications will serve as a
source of inspiration for your own work.
I would like to thank the Materials Characterization Section of the Marketing Support Group in
Schwerzenbach, Switzerland for assistance and Helga Judex for the layout.
Schwerzenbach, August 1998
METTLER TOLEDO APPLIKATIONSSAMMLUNG
Dr. Markus Schubnell
TUTORIAL-KIT
Seite 1
Overview
The METTLER TOLEDO Thermal Analysis Tutorial Kit includes 14 carefully selected samples
that enable you to measure many effects that are typically observed in thermal analysis. The
following table provides you with an overview of the measurements and evaluations that were
performed with these samples for the creation of this collection of applications.
Sample
Effect investigated
Technique used
Page
Cocoa butter
Melting
DSC
3
Oxidation stability
DSC
4
PE-HD
Crystallinity
DSC
5
Dimethyl terephthalate
Melting, Purity
DSC
6
Phenylbutazone
Polymorphism, Crystallization,
Melting
DSC
7
Printed circuit board
Glass transition
DSC
8
Glass transition
ADSC
9
Expansion/Glass transition
TMA
10
Azoxydianisole
Melting, Phase transition
DSC
11
PET
Glass transition, Crystallization,
Melting
DSC
12
Elastic behavior
TMA
13
Curing, Glass transition
DSC
14
Kinetics
DSC
15
Corundum (Al2O3)
Specific heat
DSC
16
Quartz sand
Solid-solid phase change
DSC/TMA
17/18
Copper sulfate
Dehydration
DSC
19
Dehydration, Decomposition
TGA/TGA MaxRes
20/21
Calcium oxalate
Dehydration, Decomposition
TGA
22
Enameled copper wire
Softening, Decomposition of the
insulation
TMA
23
Aluminum cylinder
Expansion coefficient
TMA
24
Epoxy powder
Seite 2
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
1
Sample
Conditions
Melting Behavior of Cocoa Butter
Cocoa butter
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, hermetically sealed
Sample preparation: Press the cocoa butter flakes into the pan with a
PTFE rod, 16.971 mg
Interpretation
DSC measurement:
Heating from 25 °C to 45 °C at 1 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Melting of Cocoa Butter
Cocoa butter can consist of different modifications:
Modification
Melting range
Amorphous
-
α (metastable)
8 - 15 °C
β ´ (metastable)
15 - 29 °C
β (stable)
above 29 °C
The relative amounts of the various modifications depend on the thermal
history of the sample. The melting temperatures, however, depend on the
chemical composition of the glycerides.
Evaluation
The first part of the DSC curve shows the melting of the metastable
β´-modification. Then, from about 29 °C onwards, the stable
β-modification melts. The percentage amount of cocoa butter melted is
shown as a function of temperature in the inserted diagram.
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
Seite 3
2
Sample
Conditions
Oxidation Stability of Cocoa Butter
Cocoa butter
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, pierced lid
Sample preparation: Press the cocoa butter flakes into the pan with a
PTFE rod
11.546 mg (in an oxygen atmosphere) and
13.665 mg (in an air atmosphere)
DSC measurement:
Heating from 100 °C to 250 °C at 10 K/min
Atmospheres:
Oxygen 50 cm3/min. Air, no flow
∧exo
Interpretation
Evaluation
Seite 4
Oxidation Stability of Cocoa Butter
The purpose of this experiment was to investigate the oxidation stability of
cocoa butter. The measurements were performed in a stationary air
atmosphere and in an atmosphere of oxygen at a flow rate 50 cm3/min. The
results show that oxidation in oxygen occurs much more rapidly than in a
stationary air atmosphere. In both cases, the temperature of the onset of
oxidation was about 190 °C.
Atmosphere
Onset temperature
oxygen
192 °C
air
190 °C
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
3
Sample
Conditions
Determination of the Crystallinity of High Density
Polyethylene
High density polyethylene film (PE-HD)
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, hermetically sealed
Sample preparation: 2 disks of PE-HD, total weight 2.530 mg
DSC measurement:
Heating from 50 °C to 160 °C at 10 K/min
Cooling from 160 °C to 50 °C at 10 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Crystallinity of PE-HD
Interpretation
The crystalline regions in the PE-HD are destroyed on melting. The
amount of heat required for the melting process is proportional to the
initial crystallinity. The percentage crystallinity of a sample can therefore
be determined by comparing the heat of fusion of the sample with that of a
100% crystalline sample.
Evaluation
The heat of fusion for 100% crystalline PE-HD is about 290 J/g. For the
tutorial kit sample, values for the crystallinity of 72.2% (heating) and
71.6% (cooling) were obtained from the measured heats of fusion.
The peak temperature of 132 °C on heating is characteristic for PE-HD.
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
Seite 5
4
Sample
Conditions
Purity of Artificially Contaminated Dimethyl Terephthalate
Contaminated dimethyl terephthalate (DMT)
e
Measuring cell:
DSC821
Pan:
Aluminum standard 40 µl, hermetically sealed
Sample Preparation: Several crystals, total weight 4.751 mg
DSC measurement:
Heating from 130 °C to 150 °C at 1 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Interpretation
Evaluation
Seite 6
Purity of Dimethyl Terephthalate
The determination of purity is based on the van’t Hoff equation. The
e
STAR software algorithm not only calculates the purity, but also yields
the melting point of the sample as well as the melting temperature at which
10% of the sample has melted. If the melting process is observed visually,
this "melting temperature" corresponds to the temperature at which a
change in the appearance of the sample can first be seen. The melting point
of the pure substance is obtained by extrapolation of the 1/F plot.
Purity
99.4 %
Melting point
140.8 °C
Melting temperature (10% melted)
138.3 °C
Melting point of the pure DMT
141.1 °C
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
5
Sample
Conditions
Polymorphism of Phenylbutazone
Phenylbutazone
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, hermetically sealed
Sample preparation: Phenylbutazone, pressed into the pan with a PTFE
rod, total weight 9.006 mg
DSC measurement:
Heating from 30 °C to 150 °C, cooling to 30 °C and a
second heating run to 150 °C;
All heating and cooling runs at 5 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Interpretation
Evaluation
Polymorphism of Phenylbutazone
Phenylbutazone can exist in stable and metastable modifications
(polymorphism). The stable form melts at about 106 °C (upper curve). On
cooling, the melt solidifies to a glassy state. On heating again, the
amorphous sample begins to crystallize at about 50 °C to the metastable
modification (lower curve, exothermic peak). The metastable form melts at
about 93 °C. At the same time, the stable modification crystallizes from
the resulting melt (endothermic peak followed by an exothermic peak). The
stable modification melts afterwards at about 104 °C. The smaller melting
peak area in comparison with that of the first measurement indicates
incomplete crystallization.
Heat of fusion of the crystallized stable modification
94 J/g
Heat of crystallization of the metastable modification
67 J/g
Melting temperature of the stable modification (onset)
106 °C
Crystallization temperature of the metastable modification (onset)49 °C
Melting temperature of the metastable modification (onset)
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
93 °C
Seite 7
6
Sample
Conditions
Glass Transition of a Printed Circuit Board
(DSC Measurement)
Printed circuit board, glass fiber epoxy
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, pierced lid
Sample preparation: Disks, 52.964 mg, smooth side facing downwards in
the pan (for better thermal conductivity)
DSC measurement:
Heating from 40 °C to 150 °C at 10 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Interpretation
Evaluation
Glass Transition of a PC Board
If the sample is measured without any thermal pretreatment (first run), the
glass transition is masked by relaxation effects. If the same sample is
measured again (or measured after thermal pretreatment, e.g. tempering for
1 minute at 130 °C), then the glass transition can be clearly observed
(second run). During the glass transition, a sharp increase in the specific
heat occurs (see the inserted diagram).
Glass transition temperature (onset)
91 °C
Glass transition temperature (midpoint)
97 °C
Change of the specific heat during the glass transition
Seite 8
0.15 J/(g K)
In comparison: onset with ADSC
91 °C
onset with TMA
95 °C
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
7
Probe
Conditions
Glass Transition of a Printed Circuit Board
(ADSC Measurement)
Printed circuit board, glass fiber epoxy
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, pierced lid
Sample preparation: Disks, 53.354 mg, smooth side facing downwards in
the pan (for better thermal conductivity)
The sample was preheated with the DSC program
(40 °C to 150 °C at 10 K/min) to obtain conditions
similar to those of the classical DSC measurement.
ADSC measurement: Heating from 40 °C to 150 °C at 1 K/min, period
1 min, amplitude 1 °C
Atmosphere:
Air, stationary environment, no flow
∧exo
Interpretation
Evaluation
Glass Transition of a PC Board
The evaluation of an ADSC measurement yields a number of additional
results. The measurement of the Total Heat Flow is that which is most
comparable with a conventional DSC experiment. The corresponding curve
(colored green) shows a glass transition at about 91 °C. The glass transition
can also be observed in the curves of the phase angle, the complex heat
capacity (cp complex) as well as the reversing heat flow (reversing).
Glass transition temperature (onset, reversing heat flow)
91 °C
In comparison: onset with conventional DSC measurement
91 °C
onset with TMA
METTLER TOLEDO APPLIKATIONSSAMMLUNG
95 °C
TUTORIAL-KIT
Seite 9
8
Sample
Conditions
Glass Transition of a Printed Circuit Board
(TMA Measurement)
Printed circuit board, glass fiber epoxy, thickness 1.519 mm
Measuring cell:
TMA/SDTA840
Probe
3 mm ball-point probe
Load:
0.1 N
Sample preparation: Smooth the surface with a fine abrasive paper; place
a quartz glass disk between the sample and the
probe.
TMA measurement: Heating from 30 °C to 250 °C at 10 K/min
Atmosphere:
Air, stationary environment, no flow
Glass Transition of a PC Board
Interpretation
Evaluation
Seite 10
The glass transition can also be determined in a TMA experiment. The
glass transition is observed as a marked change in the expansion coefficient
(second run). The result of the measurement yields a glass transition
temperature of 95 °C (onset).
If the sample is measured without any thermal pretreatment (first run), the
glass transition is masked by relaxation effects.
Glass transition temperature (onset)
95 °C
In comparison: onset with DSC
onset with ADSC
91 °C
91 °C
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
9
Sample
Conditions
Melting Behavior and Phase Transition of Azoxydianisole
4,4-Azoxydianisole
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, hermetically sealed
Sample preparation: Several crystals, total weight 5.834 mg
DSC measurement:
Heating from 100 °C to 150 °C at 5 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Interpretation
Evaluation
Melting of Azoxydianisole
When a solid melts, its crystal lattice structure is destroyed and a liquid is
formed. There is then only a relatively weak interaction between
neighboring molecules. In contrast to the isotropic properties of normal
liquids, liquid crystals also exhibit a certain degree of spatial orientation
even in the liquid state. Depending on the liquid crystal, one can
distinguish between a smectic (2 dimensional orientation) and a nematic
(1 dimensional orientation) phase. 4,4-azoxydianisole is a substance that
exists in the form of a nematic liquid crystal after melting. The liquid
crystal properties are however lost above 132 °C.
Heat of fusion of azoxydianisole
110 J/g
Melting point (onset)
117 °C
Isotropic liquid a temperature of
132 °C
Heat of transition nematic-isotropic
METTLER TOLEDO APPLIKATIONSSAMMLUNG
2.8 J/g
TUTORIAL-KIT
Seite 11
10 Thermal Behavior of Polyethylene Terephthalate
Sample
Conditions
Polyethylene terephthalate (PET)
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, lid pierced with several
holes
Sample preparation: PET disks, smooth side facing downwards in the pan
(for better thermal conductivity)
10.190 mg (in nitrogen)
DSC measurement:
Heating from 30 °C to 300 °C at 8 K/min
Atmosphere:
Nitrogen, 50 cm3/min
∧exo
Interpretation
Evaluation
Polyethylene Terephthalate
PET exhibits a glass transition accompanied by noticeable thermal
relaxation. The sample then crystallizes (exothermic peak) and finally melts
at about 230 °C. The slight slope of the baseline is caused by a gradual
increase in the specific heat.
Effect
Glass transition temperature (onset)
Crystallization temperature (onset)
Melting "point" (peak)
Heat of crystallization
Heat of fusion
∆cp Glass transition
Seite 12
TUTORIAL-KIT
74.2 °C
132 °C
254 °C
27.8 J/g
44 J/g
0.30 J/(g K)
METTLER TOLEDO APPLIKATIONSSAMMLUNG
11 Elastic Behavior of Polyethylene Terephthalate
Sample
Conditions
Polyethylene terephthalate (PET) disks, 0.4407 mm thick
Measuring cell:
TMA/SDTA840
Probe:
1 mm2 flat end probe
Load:
0.01 N / 0.1 N, period 12 s
TMA measurement: Heating from 30 °C to 200 °C at 10 K/min
Atmosphere:
Air, stationary environment, no flow
Elastic Properties of PET
Interpretation
Evaluation
At the glass transition the flat probe penetrates more and more into the
material and the sample reacts flexibly to the periodic change of load. The
amplitude maximum occurs at about 96 °C. Crystallization of the material
initiates the start of the curing process ("physical curing"), which leads to a
noticeable decrease in the amplitude. The crystallization process is
completed by about 130 °C and the sample is again hard. The contraction
of the sample as a result of the glass transition is only 6.3 µm. The curing
of the sample leads to an appreciably larger contraction.
Glass transition (onset)
76.3 °C
In comparison: onset from DSC (see page 12)
74.1 °C
6.3 µm
Contraction at the glass transition
89.3 µm
Contraction as a result of curing
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
Seite 13
12 Curing of an Epoxy Powder
Sample
Epoxy powder
Conditions
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, pierced lid
Sample preparation: Fine powder, 10.268 mg
DSC measurement:
Heating from 30 °C to 300 °C at 10 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Interpretation
Evaluation
Curing of an Epoxy Powder
The epoxy powder liquefies at about 65 °C (glass transition with marked
thermal relaxation). The curing of the resin occurs above about 160 °C. The
very small exothermic peak that is hardly noticeable in the curing peak is
caused by the melting of dicyandiamide (a constituent of the accelerator).
After curing, the epoxy resin is a glassy mass; correspondingly a glass
transition at 104 °C (onset) can be observed in the second heating run. In
this case also, a weak thermal relaxation effect is visible.
Glass transition
65 °C
Thermal relaxation
8.4 J/g
Curing begins at
160 °C
Heat of curing
49.4 J/g
Glass transition (onset) of the cured resin
104 °C
cp change during the glass transition
Seite 14
TUTORIAL-KIT
0.23 J/(g K)
METTLER TOLEDO APPLIKATIONSSAMMLUNG
13 Kinetics of Curing of an Epoxy Powder
Sample
Epoxy powder
Conditions
Measuring cell:
DSC821
Pan:
Aluminum standard 40 µl, pierced lid
e
Sample preparation: Fine powder, various sample weights
DSC measurement:
Heating from 30 °C to 300 °C at heating rates of 2,
5 and 10 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Interpretation
Kinetics of Curing of an Epoxy Powder
In order to determine the kinetics of a chemical reaction several preliminary
experiments are run at different heating rates. The activation energy can
then be determined on the basis of the conversion curves using the model
free kinetics program.
The kinetic parameters determined in this way can be checked with an
isothermal experiment. To do this, the sample at room temperature is put
into the DSC821e module that has already been heated up to the desired
isothermal temperature. The conversion curve is calculated from the
measurement curve and is then compared with the results of the
experiment with model free kinetics.
Evaluation
The conversion curve of the sample of epoxy powder run isothermally at
185 °C agrees quite well with the results obtained from model free kinetics.
It is now possible to estimate the time needed to cure the epoxy powder at
190 °C. The table shows that the curing time has been reduced by roughly
4 minutes (for 95% curing).
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
Seite 15
14 Specific Heat Capacity (cp) of Corundum
Sample
Conditions
Corundum (aluminum oxide powder, alumina)
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, pierced lid
Sample preparation: Aluminum oxide powder, 33.13 mg; the powder was
heated at 120 °C for 1 minute before weighing, in
order to remove any moisture
DSC measurement:
Isothermal for 2 min at 40 °C
Heating from 40 °C to 150 °C at 10 K/min
Blank curve corrected
Atmosphere:
Air, stationary atmosphere, no flow
∧exo
Interpretation
Evaluation
Seite 16
Specific Heat of Alumina
e
The STAR software offers two different procedures for performing cp
measurements: a direct method and the so called sapphire method. The
direct method determines cp from the blank curve corrected DSC signal. In
contrast, the sapphire method determines cp by making a direct comparison
with the heat capacity of sapphire.
Temperature
cp Sapphire
cp Direct
cp Literature
60 °C
842 mJ/(g K)
853 mJ/(g K)
844 mJ/(g K)
80 °C
876 mJ/(g K)
877 mJ/(g K)
877 mJ/(g K)
100 °C
908 mJ/(g K)
908 mJ/(g K)
907 mJ/(g K)
120 °C
935 mJ/(g K)
942 mJ/(g K)
934 mJ/(g K)
140 °C
961 mJ/(g K)
974 mJ/(g K)
959 mJ/(g K)
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
15 Phase Transition of Quartz Sand (DSC Measurement)
Sample
Conditions
Quartz sand
Measuring cell:
DSC821e
Pan:
Aluminum standard, 40 µl, pierced lid
Sample preparation: Quartz sand, 16.435 mg
DSC measurement:
Heating from 400 °C to 640 °C at 10 K/min
Atmosphere:
Air, stationary environment, no flow
∧exo
Interpretation
Evaluation
Phase Transition of Quartz
α-quartz or crystalline silicon dioxide is a widely occurring mineral. The αmodification, which is stable at room temperature, changes to β-quartz at
575 °C (solid-solid phase transition). The transition enthalpy is 7.5 J/g.
The phase change is also accompanied by a change in specific heat.
Phase transition (onset)
574.0 °C
Enthalpy
7.51 J/g
cp change as a result of the phase change
0.17 J/(g K)
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
Seite 17
16 Phase Transition of Quartz Sand (TMA Measurement)
Sample
Conditions
Quartz sand, single grain, 40 µg
Measuring cell:
TMA/SDTA840
Probe:
3 mm ball-point probe
Load:
0.3 N
TMA measurement: Heating from 400 °C to 650 °C at 10 K/min
Blank curve corrected
Atmosphere:
Air, stationary environment, no flow
Phase Transition of Quartz
Interpretation
Evaluation
Seite 18
α-quartz or crystalline silicon dioxide is a widely occurring mineral. The
α-modification, which is stable at room temperature, changes to β-quartz
at 575 °C (solid-solid phase transition). This phase change leads to a very
marked expansion. The expansion coefficient of the β-modification is
slightly negative, i.e. the quartz sand grain gradually contracts.
Phase transition (onset)
570 °C
Expansion of the grain of quartz sand at the phase transition
490 nm
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
17 Dehydration of Copper Sulfate Pentahydrate
Sample
Conditions
Copper sulfate pentahydrate (CuSO4 • 5 H2O)
Measuring cell:
DSC821e
Pan:
Aluminum standard 40 µl, pierced lid
Sample preparation: Copper sulfate, finely ground, 12.424 mg
Copper sulfate crystals, 11.184 mg,
DSC measurement:
Heating from 40 °C to 300 °C at 10 K/min
Atmosphere:
Nitrogen, 50 cm3/min
∧exo
Interpretation
Dehydration of Copper Sulfate Pentahydrate
When copper sulfate pentahydrate is heated, it looses its water of
crystallization. This dehydration process occurs in three steps at different
temperatures according to the following equations:
CuSO4 • 5 H2O
⇔
CuSO4 + 2 H2O
(I)
CuSO4 • 3 H2O
⇔
CuSO4 + 2 H2O
(II)
CuSO4 • H2O
⇔
CuSO4 + 1 H2O
(III)
If the copper sulfate crystals are ground, the first two dehydration steps
can be clearly separated. The same degree of separation can not be obtained
at this heating rate with crystals that have not been ground.
Evaluation
The average energy of the bond between the water of crystallization and
the CuSO4 can be estimated from the enthalpy values. If the temperature
independent values of 4.186 J/(g K) and 2253 J/g are assumed for the
specific heat and the heat of evaporation of water respectively, then a
value of 224 J/(g water of crystallization) is obtained for the average bond
energy of the water of crystallization.
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
Seite 19
18 Thermal Decomposition of Copper Sulfate Pentahydrate
Sample
Conditions
Copper sulfate pentahydrate, (CuSO4 • 5 H2O)
Measuring cell:
TGA/SDTA850
Pan:
Alumina 70 µl, open
Sample preparation: Finely ground, 31.5 mg
TGA measurement:
Heating from 25 °C to 1000 °C at 10 K/min, blank
corrected
Atmosphere:
Nitrogen, 50 cm3/min
Thermal Decomposition of Copper Sulfate Pentahydrate
Interpretation
Evaluation
Seite 20
As previously described (see page 19), hydrated copper sulfate loses its
water of crystallization in several steps. The resulting anhydrous copper
sulfate then decomposes in 3 further reaction steps:
2 CuSO4
⇔
Cu2(SO4)O + SO3
(I)
Cu2(SO4)O
⇔
CuO + SO3
(II)
2 CuO
⇔
Cu2O + _O2
(III)
Reaction step
∆m stoichiometric
∆m measured
Dehydration (total)
36.1 %
35.8 %
Reaction I+II
32.1 %
32.1 %
Reaction III
3.2 %
3.2 %
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
19
Sample
Conditions
Dehydration of Copper Sulfate Pentahydrate (TGA)
Copper sulfate pentahydrate, (CuSO4 • 5 H2O)
Measuring cell:
TGA/SDTA850
Pan:
Alumina 70 µl, open
Sample preparation: Finely ground crystals, 33.025 mg
TGA measurement:
Heating from 25 °C to 1000 °C with MaxRes
Atmosphere:
Nitrogen, 50 cm3/min
Dehydration of Copper Sulfate Pentahydrate
Interpretation
Without the use of MaxRes, the first two dehydration steps can not be
clearly separated (see previous page). The MaxRes option automatically
adjusts the heating rate to the rate of change of the sample weight; a rapid
weight loss leads to a reduction of the heating rate, a very gradual weight
loss to an increase of the heating rate. The TG curve shows that with
MaxRes the first two dehydration steps are clearly separated. No blank
curve correction can of course be made with MaxRes because of the
variable heating rate. In addition, the experiment usually lasts appreciably
longer than a “conventional” TG experiment at a typical heating rate of
10 K/min.
Evaluation
Copper sulfate pentahydrate loses 2 molecules of water in each of the first
two dehydration steps. This leads to a weight loss of 14.4% for each step.
The measured weight losses were 14.3% and 14.2% without MaxRes and
14.4% and 14.0% with MaxRes.
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
Seite 21
20 Thermal Decomposition of Calcium Oxalate Monohydrate
Sample
Conditions
Calcium oxalate monohydrate, CaC2O4 • H2O
Measuring cell:
TGA/SDTA850
Pan:
Alumina 70 µl, open
Sample preparation: CaC2O4 • H2O powder, 19.45 mg
TGA measurement:
Heating from 30 °C to 1000 °C at 15 K/min
Blank curve corrected
Atmosphere:
Nitrogen, 20 cm3/min
Decomposition of Calcium Oxalate Monohydrate
Interpretation
Above about 120 °C, CaC2O4 • H2O loses its water of crystallization. The
anhydrous oxalate then decomposes in 2 reaction steps:
CaC2O4
⇒
CaCO3 + CO
(I)
CaCO3
⇔
CaO + CO2
(II)
The onset temperatures of the individual reaction steps can be determined
from the TGA signal (not evaluated in this example), the first derivative of
the TG signals (DTG curve) or the SDTA signal.
Evaluation
Seite 22
Dehydration
∆m
(stoichiometry)
-12.3%
Reaction (I)
-19.18%
-19.2%
484 / 481 °C
Reaction (II)
-30.14%
-30.9%
715 / 713 °C
Reaction step
TUTORIAL-KIT
∆m
(measured)
-12.7%
Onset
(SDTA/DTG)
144 / 144 °C
METTLER TOLEDO APPLIKATIONSSAMMLUNG
21
Sample
Conditions
Thermomechanical Behavior of Enameled Copper Wire
Insulated copper wire, 7 mm long, diameter 0.317 mm
Measuring cell:
TMA/SDTA840
Probe:
3 mm ball-point probe
Load:
0.1 N
TMA measurement: Heating from 30 °C to 360 °C at 20 K/min
Oxygen, 20 cm3/min
Atmosphere:
Stability of Enamel on Copper Wire
Interpretation
Evaluation
The coating of the copper wire softens at about 85 °C (glass transition). It
begins to decompose at about 200 °C. The thickness of the coating is
21 µm (half of the total step). The diagram also shows the degree of
decomposition of the sample as a function of temperature. Decomposition
is complete by about 310 °C.
Glass transition temperature (onset)
86 °C
Decomposition of the coating begins at (from conversion) ≈200 °C
21 µm
Original thickness of the coating
METTLER TOLEDO APPLIKATIONSSAMMLUNG
TUTORIAL-KIT
Seite 23
22 Expansion Coefficient of Aluminum
Sample
Conditions
Aluminum cylinder, 4.652 mm long
Measuring cell:
TMA/SDTA840
Probe:
3 mm ball-point probe
Load:
0.1 N
TMA measurement: Heating from 30 °C to 200 °C at 10 K/min
Blank curve corrected
Atmosphere:
Air, stationary environment, no flow
Expansion Coefficient of Aluminum
Seite 24
TUTORIAL-KIT
METTLER TOLEDO APPLIKATIONSSAMMLUNG
Interpretation
The expansion coefficient α is defined as the relative change in length of a
sample when its temperature is increased:
α=
dL 1
⋅
.
dT L0
Often, the so-called average expansion coefficient,
∆L 1
α mean =
,
⋅
∆T L0
is used, where ∆L refers to the length L0 at room temperature, and ∆T to
the temperature difference between the sample temperature and room
temperature. In general, the coefficient of linear expansion is dependent on
the direction of measurement.
Evaluation
Temperature [°C]
METTLER TOLEDO APPLIKATIONSSAMMLUNG
Expansion coefficient [ppm/K]
60
23.4
120
25.6
180
26.1
TUTORIAL-KIT
Seite 25
Mettler-Toledo GmbH,
Analytical,
CH-8603 Schwerzenbach, Switzerland
Phone +41-1-806 77 11, Fax +41-1-806 73 50
Internet: http://www.mt.com
AT Mettler-Toledo GmbH., A-1100 Wien
Tel. +43-1-604 19 80, Fax +43-1-604 28 80
AU Mettler-Toledo Ltd., Port Melbourne, Victoria 3207
Tel. +61-3-9644 5700, Fax +61-3-9645 3935
BE N.V. Mettler-Toledo s.a., B-1651 Lot
Tel. +32-2-334 02 11, Fax +32-2-378 16 65
CH Mettler-Toledo (Schweiz) AG, CH-8606 Greifensee
Tel. +41-1-944 45 45, Fax +41-1-944 45 10
CN Mettler-Toledo (Shanghai) Ltd., Shanghai 200233
Tel. +86-21-6485 0435, Fax +86-21-6485 3351
CZ Mettler-Toledo, spol, s.r.o., CZ-12000 Praha 2
Tel. +420-2-25 49 62, Fax +420-2-2424 7583
DE Mettler-Toledo GmbH, D-35353 Giessen
Tel. +49-6-41 50 70, Fax +49-6-41 507 128
DK Mettler-Toledo A/S, DK-2600 Glostrup
Tel. +45-4327 0800, Fax +45-4327 0828
ES Mettler-Toledo S.A.E., E-08038 Barcelona
Tel. +34-3-223 22 22, Fax +34-3-223 02 71
FR Mettler-Toledo s.a., F-78222 Viroflay
Tel. +33-1-3097 1717, Fax +33-1-3097 1616
HK Mettler-Toledo (HK) Ltd., Kowloon
Tel. +852-2744 1221, Fax +852-2744 6878
HR Mettler-Toledo, d.o.o., HR-10000 Zagreb
Tel. +385-1-230 41 47, Fax +385-1-233 63 17
HU Mettler-Toledo, KFT, H-1173 Budapest
Tel. +36-1-257 70 30, Fax +36-1-256 21 75
IT Mettler-Toledo S.p.A., I-20026 Novate Milanese
Tel. +39-2-333 321, Fax +39-2-356 29 73
JP Mettler-Toledo K.K., Osaka 540-6017
Tel. +81-6-949 59 01, Fax +81-6-949 59 45
KR Mettler-Toledo (Korea) Ltd., Seoul (135-090)
Tel. +82-2-518 20 04, Fax +82-2-518 08 13
KZ Mettler-Toledo CA, 480009 Almaty
Tel. +7- 3272-608 834, Fax +7-3272-608 835
MY Mettler-Toledo (M) Sdn. Bhd. 47301 Petaling Jaya
Tel. +60-3-703 27 73, Fax +60-3-703 17 72
MY Mettler-Toledo (S.E.A.), 47301 Petaling Jaya
Tel. +60-3-704 17 73, Fax +60-3-703 17 72
MX Mettler-Toledo S.A. de C.V., México C.P. 06430
Tel. +52-5-547 57 00, Fax +52-5-541 22 28
NL Mettler-Toledo B.V., NL-4000 HA Tiel
Tel. +31-3-4463 8363, Fax +31-3-4463 8390
PL Mettler-Toledo, Sp. z o.o., PL-02-929 Warszawa
Tel. +48-22-651 92 32, Fax +48-22-651 71 72
RU Mettler-Toledo C.I.S. AG, 10 1000 Moscow
Tel. +7-095-921 92 11, Fax +7-095-921 63 53
SE Mettler-Toledo AB, S-12008 Stockholm
Tel. +46-8-702 50 00, Fax +46-8-642 45 62
SG Mettler-Toledo (S) Pte. Ltd., Singapore 139944
Tel. +65-7786 779, Fax +65-7786 639
SK Mettler-Toledo, SK-82104 Bratislava
Tel. +421-7-4342 7496, Fax +421-7-4333 7190
SI Mettler-Toledo, d.o.o., SI-1236 Trzin
Tel. +386-61-162 18 01, Fax +386-61-162 17 89
TH Mettler-Toledo (Thailand) Ltd., Bangkok 10310
Tel. +66-2-719 64 80, Fax +66-2-719 64 79
TW Mettler-Toledo Pac Rim AG, Taipei
Tel. +886-2-2579 5955, Fax +886-2-2579 5977
UK Mettler-Toledo Ltd., Leicester, LE4 1AW
Tel. +44-116-235 70 70, Fax +44-116-236 63 99
US Mettler-Toledo, Inc., Columbus, OH 43240
Tel. +1-614-438 4511, Fax +1-614-438 4900
For all other countries: Mettler-Toledo GmbH
PO Box VI-400, CH-8606 Greifensee
Tel. (++ 41 1) 944 22 11, Fax (++41 1) 944 31 70
Mettler-Toledo GmbH, Analytical
Sonnenbergstrasse 74
CH-8603 Schwerzenbach, Switzerland
Phone
(++41 1) 806 77 11
Fax
(++41 1) 806 73 50
Subject to technical changes
© 01/99 Mettler-Toledo GmbH, ME-51709920
P&D MarCom Schwerzenbach
Printed in Switzerland on 100% chlorine-free paper,
for the sake of our environment.
METTLER TOLEDO on the WWW
You can also reach us on World Wide Webb. There you will
find information on other products and services of METTLER
TOLEDO and interesting information about our company.
The address is: http://www.mt.com