Materials Characterization by Thermal Analysis (DSC & TGA), Rheology, and
Dynamic Mechanical Analysis
Charles Potter Thermal Application Scientist
Sarah Cotts Rheology Application Scientist
Fred Wiebke Territory Manager
TA Instruments
Facts about TA Instruments
Global market leader in thermal analysis, thermophysical properties, microcalorimetry and rheology.
Headquartered in New Castle, DE along with 200,000 sq. ft. of manufacturing and support
Additional manufacturing in Utah and Germany
Direct Sales Offices in 28 countries
What Does TA Instruments Measure?
Thermal Analysis & Rheology
DSC, DTC
TGA
DMA Rheometer
TMADIL
Thermal Analysis, Rheology,
Thermophysical Properties Techniques
Differential Scanning Calorimetry (DSC)
Modulated DSC
Thermogravimetric Analysis (TGA)
Vapor Sorption Analysis (SA)
Dynamic Mechanical Analysis (DMA)
Rheometer
Isothermal Calorimetry (TAM)
Thermomechanical Analysis (TMA)
Flash Diffusivity
Thermal Conductivity
Dilatometry (DIL)
Agenda
Morning: Techniques and Applications
Case Study Automotive Industry
Differential Scanning Calorimetry
Thermogravimetric Analysis
Simultaneous Differential Thermal Analysis
Complimentary Thermal Analysis Techniques
Afternoon: Techniques and Applications:
Dynamic Mechanical Analysis (Q800 and RSA)
Rheology (DHR and ARES) Techniques and Applications
Case Studies Rheology/DSC/TGA/SDT
Rubber Rheology
Case Studies Rubber Rheology and DSC
Load Frame High Force, Fatigue Testing
Wrap up about 4:00 pm
- Case Study -
Thermal Analysis in the
Automotive Industry
Composition of an Automobile
Building a Lighter Automobile
30% weight reduction 50% weight reduction
Aluminum Tailor
Welded Blanks
40% weight reduction / 50%
reduction in part count
Superplastic Forming
35% weight reduction /
reduction in part count
40% weight reduction / 10 X
reduction in part count
Hydroforming
Metal Matrix
Composites
Powertrain components - 40%
weight reduction
Reduces mass by 60%
Magnesium AlloyLightweight Glazing Thermoplastic
Composites
Photo: Courtesy of GKN Aerospace
What is Thermal Analysis?
Thermal analysis is a series of techniques that provide physical property measurement as a function of temperature, time, and other variables.
Common Techniques Include
Differential Scanning Calorimetry (DSC) - heat
Modulated DSC (MDSC)
Thermogravimetric Analysis (TGA) weight
Simultaneous DSC/TGA (SDT)
Vapor sorption analysis
Thermomechanical Analysis (TMA) - dimension
Dynamic Mechanical Analysis (DMA) - modulus
Can also be considered a solids rheometer
Analysis of Automotive Materials
What is it?
Thermoplastics
Thermosets
Amorphous Material
Rubber and Elastomers
What is it?
What is it? or What is it not?
DSC and TGA, along with infrared spectroscopy, are an excellent starting point for characterization of new or unknown materials.
In Canada You will need a bunch of this to buy
anything including a CAR
-2
-1
0
1
2
3
He
at
Flo
w T
4P
(W
/g)
-50 0 50 100 150 200 250
Temperature (C)
Exo Up Universal V4.5A TA Instruments
Thermoplastic Polymers
Agenda Thermoplastics
What are thermoplastics?
Melting
Crystallization
Crystalline Content
Thermal Stability
Oxidative Stability
Thermoplastics
Semi-Crystalline (or Amorphous)
Crystalline Phase
melting temperature Tm
(endothermic peak)
Amorphous Phase
glass transition
temperature (Tg)
(causing Cp)
Tg < TmCrystallizable polymer can crystallize
on cooling from the melt at Tc
(Tg < Tc < Tm)
DSC Melting of Polyethylene vs Indium
100 110 120 130 140 150 160 170
-20
-15
-10
-5
0
5
Temperature (C)
He
at
Flo
w (
mW
)
126.96C191.7J/g
156.59C28.74J/g
131.12C
156.85C
Different Types of Polyethylene
Peak shape depends on:
Molecular weight distribution and branching
Crystallinity
Crystallite morphology as determined by thermal history
Differences affect end-use performance
-20
-15
-10
-5
0
Heat
Flo
w (
W/g
)
40 60 80 100 120 140 160Temperature (C)Exo Up
Crystallization
Crystallization is an exothermic peak in a DSC scan
Crystallization is molten amorphous material changing to crystalline material upon cooling
Cold-Crystallization is solid amorphous material changing to crystalline material upon heating
Crystallization is a kinetic, two-step process Nucleation
Crystal growth
Crystallization
Crystallization is a kinetic process which is typically studied either while cooling or isothermal, but can also be studied during heating (Cold-Crystallization)
Differences in crystallization temperature or time (at a specific temperature) between samples can affect end-use properties as well as processing conditions
Isothermal crystallization is the most sensitive way to identify differences in crystallization rates
Effect of Cooling Rate
Cooling
Re-crystallization
20C/min
10C/min
5C/min
2.5C/min
1.25C/min
0
2
4
6
8
He
at
Flo
w (
W/g
)
-20 30 80 130 180
Temperature (C)
Exo Up Universal V4.4A TA Instruments
115 120 125 130 1350
2
4
6
What is happening?
11001000 1020 1040 1060 1080
Temperature (C)
0.4
-0.2
0.0
0.2
Gold CKK hermetic lid
Exo Up
0.0
0.5
1.0
1.5
2.0
Hea
t F
low
(W
/g)
40 50 60 70 80 90 100 110 120 130 140 150 160
Temperature (C)Exo Up
POLYPROPYLENE
WITH NUCLEATING
AGENTS
POLYPROPYLENE
WITHOUT
NUCLEATING AGENTS
-1.5
-1.0
-0.5
0.0
Hea
t F
low
(W
/g)
60 80 100 120 140 160 180 200
Temperature (C)Exo Up
Crystallization
melting
Effect of Nucleating Agents
Cooling
What is Isothermal Crystallization?
A Time-To-Event Experiment
Annealing Temperature
Melt Temperature
Isothermal Crystallization
Temperature
Time
Zero Time
Isothermal Crystallization
Crystallization
Heat capacity due to cooling
-1
0
1
2
3
He
at
Flo
w (
mW
)
0 2 4 6 8 10 12 14 16
Time (min)
Te
mp
era
ture
Temperature Time-to-Tmax characterizes differences
A time-to-event analysis
Requires rapid cooling and equilibration
Polyethylene Oxide
Determination of Crystallinity of a common Automotive Thermoplastic:
PET/ABS Blend - Conventional DSC
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
-0.8
Temperature (C)50 100 150 200 250
He
at F
low
(W
/g)
first heat on molded part
(Curve shifted on Y axis to avoid overlap)
second heat after 10C/min cooling
120.92C67.38C
70.262C (H)235.36C
111.82C9.016J/g
22.63J/g
249.75C
9.22 mg sample, nitrogen purge 10C/minute heating rate
PET/ABS Blend - MDSC
8.46mg sample
nitrogen purge
2C/minute heating rate, 1C amplitude, 60 second period
first heat on molded part
PET Tg
ABS Tg
-0.10
-0.11
-0.12
-0.13
-0.14
-0.15
Temperature (C)
40 60 100 120 140
He
at
Flo
w (
mW
)
20 80 160
-0.02
-0.03
-0.04
-0.05
-0.06
-0.04
-0.05
-0.06
-0.07
-0.08
-0.09
(
) N
on
rev.
He
at
Flo
w (
W/g
)
(
) R
ev.
He
at F
low
(W
/g)
67.00C
+72.89C (H)
104.45C
107.25C (H)
180 200
Thermal and Oxidative Stability
Thermal and Oxidative Stability
Can be studied by multiple techniques
Studied in inert or oxidizing atmospheres
TGA Best starting point
Weight loss or gain
DSC
Change in heat flow (typically exothermic)
Can also see the effect in other techniqueslike DMA & TMA
Starting Point for Material Characterization
First Step Thermogravimetric Analysis
Look for:
Thermal and Oxidative Stability
Volatiles
Decomposition Temperature
Weight Loss Profile
Number of Steps
Residue
Char/Ash/Filler Presence
Oxidative Stability - Polypropylene
431.95C285.40C
0
20
40
60
80
100
120
Weig
ht
(%)
0 200 400 600 800 1000
Temperature (C)
PP Resin Nitrogen PP Resin Air
Universal V4.3A TA Instruments
Polyethylene Oxidation Onset Temperature
245.22C
125.54C
-20
-10
0
10
20
Heat Flo
w (m
W)
50 100 150 200 250 300Temperature (C)
Oxidation Onset Temperature (OOT)
OIT of LDPE of Cable Coatings
200 200 200 200 CCCC
Thermal Stability of Polymers
Method Log: 1:Select gas: 1 - N21: Ramp 20.00 C/min to 650.00 C2: Select gas: 2 - Air3: Ramp 20.00 C/min to 1000.00 C
PVC
PMMA
PET
650.00C55.59%
650.00C5.928%
LDPE
PEEK
650.00C14.32%
0
20
40
60
80
100
We
ight
(%)
50 250 450 650 850 1050
Temperature (C)
Block versus Random Copolymers
0 100 200 300 400 5000
50
100
Temperature (C)
Weig
ht
(%)
S - MS
RANDOM
S - MS BLOCK
P - MS
PS
size: 8 mgprog: 6C/minatm: 300 Pa vacuum
Thermosets
Thermosets
Thermosetting polymers react (cross-link) irreversibly.
A+B will give out heat (exothermic) when they cross-
link (cure). After cooling and reheating C will have only
a glass transition Tg.
A + B C
GLUE
Thermosetting Polymers
Thermogravimetric Analysis Thermal and Oxidative Stability
Composition and Filler
Flame Retardants
Differential Scanning Calorimetry Glass Transition Temperature
Heat of Reaction
Heat Capacity
Extent of cure
Other Techniques Viscosity
Modulus
Dimensional Change and CTE
Thermal Conductivity
Dielectric
Others
Curing of a Thermosetting Material
116.07C
76.30C195.0J/g
20 Min Epoxy Cured in DSC15.15mg @ 10C/min
-6
-4
-2
0
2
4
6
8
He
at F
low
(m
W)
0 50 100 150 200
Temperature (C)Exo Up Universal V4.3A TA Instruments
Interpretation of peak shape
Heat flow displacement proportional to reaction rate, dx/dt
Fraction of peak area is fraction reacted, x
Kinetic equation:
dx/dt = fn(x)*KeEa/RT
Predict reaction rates
Kinetically Controlled Processes
71.55C
225.9J/g20
40
60
80
Are
a P
erc
ent
(%)
-4
-2
0
2
4
6
8
Heat
Flo
w T
4P
(m
W)
-50 0 50 100 150Temperature (C)Exo Up
Epoxy cure
Effect of Heating Rate
128.29C0.5594W /g
122.26C323.9J/g
137.04C0.9506W /g
130.12C315.5J/g
149.93C1.972W /g
141.85C315.1J/g
160.93C3.431W /g
151.92C320.0J/g
172.86C5.792W /g
162.53C320.5J/g
-2
0
2
4
6
He
at F
low
T4 (
W/g
)
100 120 140 160 180 200 220 240
Temperature (C)
1C/min2C/min5C/min10C/min20C/min
Amorphous Structure
Characterization of Amorphous Structure
Glass Transition (Tg)
Due to amorphous (non-crystalline) structure
Due to macro-molecular motion (translational); i.e., the entire molecule is free to move relative
to adjacent molecules.
Extremely important transition because the significant change in molecular mobility at Tg causes significant changes in physical properties and reactivity
Changes at the Tg
Heat Flow
Heat Capacity
Temperature Below Tg - lower Cp - lower Volume - lower CTE - higher stiffness - higher viscosity - more brittle - lower enthalpy
Glass Transition is Detectable by DSCBecause of a Step-Change in Heat Capacity
-1.0
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
[ ] H
eat F
low
(m
W)
0.5
1.0
1.5
2.0
Heat C
apacity (
J/g
/C
)
70 90 110
Temperature (C)Exo Up Universal V3.8A TA Instruments
Polystyrene - Modes of Molecular Motion/Mobility
Vibration
Rotation
Translation
Elastomer Tg by DSC
-62.63C(H)
Elastomer - 10.18mgDSC - 10C/min
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0H
ea
t F
low
(m
W)
-80 -60 -40 -20 0 20
Temperature (C)Exo Up Universal V4.3A TA Instruments
Quantification of Amorphous Structure
% Amorphous = 0.145/0.353 = 41%
Change in Cp @ Tg is a measure of amorphous structure
Partially Miscible Amorphous Phases
108.59C(H)0.1007J/g/C
140.13C(H)0.1313J/g/C
105.16C(H)0.2657J/g/C
145.60C(H)0.1715J/g/C
PC
ABS-PC
ABS
1.2
1.4
1.6
1.8
2.0
2.2
2.4
Rev C
p (
J/g
/C
)
80 100 120 140 160Temperature (C)
If not miscible then Tgs dont shift
If completely miscible then a single Tg in the middle
ABS-PC Copolymer Alloy
Glass Transition by TMA and DMA
Glass Transition Temperature by TMA
Sample: PMMAHeating Rate: 5C/minMacro expansion probe0.05N force
92.41C
-40
-20
0
20
40
Dim
en
sio
n C
han
ge (
m
)
25 75 125
Temperature (C)
Tg is the Extrapolated Onset Temperature
Glass Transition Temperature by DMA
150.49C156.10C
151.64C
Polycarbonate1Hz, 15m amplitude3C/min
0.0
0.5
1.0
1.5
Ta
n D
elta
0.1
1
10
100
1000
10000
Lo
ss M
od
ulu
s (
MP
a)
0.1
1
10
100
1000
10000
Sto
rag
e M
od
ulu
s (
MP
a)
100 120 140 160 180
Temperature (C) Universal V4.3A TA Instrum ents
Tg can be the Extrapolated Onset Temperature of Modulus Change
Tg can be the Peak of the Loss Modulus
Tg can be the Peak of the Tan Delta
Overview of DSC and TGA for Rubber and Elastomers
Thermogravimetric Analysis (TGA)
TGA measures amount and rate of weight change vs. temperature or time in a controlled atmosphere
Used to determine composition and thermal stability up to 1000C (55 & 550); 1200C (Discovery 5500) & 1500C (650 SDT)
Characterizes materials that exhibit weight loss or gain due to decomposition, oxidation, or dehydration
Styrene-Butadiene Rubber Analysis
0 200 400 600 800 1,0000
25
50
75
100
Temperature (C)
Wt (%
)
8.4% Oil
50.4% Polymer
Air
36.2% Carbon Black
5% Inert Filler
Sample weight: 30 mg
Program rate : 20C/min
Atmosphere : N , Air2
TGA of Tire Rubber
6.122% Oil(0.6654mg)
51.84% Polymer(5.634mg)
38.96% Carbon(4.234mg)
Residue:3.013%(0.3275mg)
TGA Analysis10.87 mg of Tire Rubber Compound20C/min to 600 C in N220C/min to 1000C in air
0
2
4
6
8
10
12
Deriv. W
eig
ht (%
/min
)
0
20
40
60
80
100
Weig
ht (%
)
0 200 400 600 800 1000
Temperature (C) Universal V4.5A TA Instruments
TGA of Rubber in Nitrogen
424.01C
487.73C
141.62C
1.202%(0.1205mg)
62.81%(6.297mg)
Residue:32.14%(3.223mg)
-1
1
Deriv. W
eig
ht (%
/C
)
20
40
60
80
100
120
Weig
ht (%
)
200 400 600 800 1000
Temperature (C)
Sample: Rubber 10C/min N2 - Green ColorantSize: 10.0264 mg
TGA Rubber in Air
420.58C
477.91C
1.567%(0.1551mg)
76.50%(7.569mg)
Residue:21.69%(2.146mg)
-2
0
2
4
6
Deriv. W
eig
ht (%
/C
)
20
40
60
80
100
120
Weig
ht (%
)
200 400 600 800 1000
Temperature (C)
Sample: Rubber 10C/min Air - Green ColorantSize: 9.8941 mg
TGA Rubber in Air vs Nitrogen
1.567%(0.1551mg)
76.50%(7.569mg)
Residue:21.02%(2.080mg)
1.202%(0.1205mg) 62.81%
(6.297mg)
Residue:32.14%(3.223mg)
420.58C
477.91C
424.01C 487.73C
-2
0
2
4
6
Deriv. W
eig
ht (%
/C
)
20
40
60
80
100
120
Weig
ht (%
)
200 400 600 800 1000
Temperature (C)
Rubber 10Cmin Air - Green Colorant.UA Rubber 10Cmin N2 - Green Colorant.UA
Decomposition of Elastomers in Nitrogen
Volatilization of Plasticizers/Oils
Vacuum Can Improve Separation
Ambient Pressure
EPDM Rubber @ 10C/min
100 millitorr
-20
0
20
40
60
80
100
120
We
ight
(%)
0 100 200 300 400 500 600
Temperature (C) Universal V4.3A TA Instruments
TGA: Evolved Gas Analysis
Discovery Mass Spectrometer (DMS)
Benchtop, unit resolution quadrupole mass spec designed and optimized for evolved gas analysis (EGA)
Quadrupole detection system includes
a closed ion source
a quadrupole mass filter assembly
dual detector system (Faraday and Secondary Electron Multiplier)
ensuring excellent sensitivity from ppb to percent concentrations
TGA-MS Example: Aspirin
Summary
Thermal analysis is widely used in the automotive industry
The techniques used to characterize the automotive materials are universally applicable to other industries since they use same materials
So lets look at each of the common thermal-analytical materials in greater detail
TA Instruments DSC Models
DSC 25DSC 250 DSC 2500
Discovery DSC
Q2000AutoQ20
What is a Differential Scanning Calorimetry
A DSC measures the difference in Heat Flow Rate between a sample and inert reference as a function of time and temperature
The DSC Heat Flow Rate Equation
A DSC measures the difference in Heat Flow Rate between a sample and inert reference as a function of time and temperature.
A DSC is calibrated for the heat flow enthalpy and temperature. Baseline calibrations are performed per manufacturers recommendations.
t)(T,dt
dT Cp
dt
dHf+=
Instrument setup factors affecting calibration
Purge GasRe-calibrate baseline/Tzero, temperature and cell constant
Thermal conductivity of helium Thermal conductivity of nitrogen/air/oxygen Thermal conductivity of argon
Cooling AccessoriesRe-calibrate baseline/Tzero, temperature and cell constant
The position of the cooling head around the cell will affect the calibration of the instrument. Uninstallation and reinstallation of a cooling accessory or changing the cooling accessory warrants a complete re-calibration
Pan selectionRe-calibrate temperature and cell constant
It will not impact the baseline/Tzero calibration
General calibration and verification guidelines
Calibration
Use Calibration Mode
Calibrate upon installation
Re-calibrate if does not pass verification or if instrument setup is modified (see previous slide)
Verification
Determine how often to verify data
Run a reference material as a sample (in standard mode)
Compare results vs literature values
If results are within your tolerance system checks out and does not need re-calibration
If results are out of tolerance, then re-calibrate
400-100 -50 0 50 100 150 200 250 300 350
Temperature (C)
20
-20
-15
-10
-5
0
5
10
15
Heat Flow (W)
Empty Cell Baseline DSC2500
Heat Flow Change During a Transition
Heat Cool Heat of High Density Polyethylene
200-100 -50 0 50 100 150
Temperature (C)
4
-4
-3
-2
-1
0
1
2
3
Heat Flow (Normalized) (W/g)
Exo Up
Cool Cycle
First Heat Cycle
Second Heat Cycle
Oxidative Induction Time of Polyolefin Film
MDSC of a Process Oil
Separation of a Tg from Crystallization
A Glass Transition is Reversible
10mg PMMA Sample at Different Heating Rates
Aged Epoxy: The Tg On The First Heat Cycle
Depending on the thermal history of amorphous (glassy) polymers, the glass transition can appear as a simple step in the baseline or one that has a substantial endothermic peak that can be misinterpreted as a melting peak.
Epoxy Cured 48 Hours : Heat Cool Heat
5 Min Epoxy - 9.85mgCured 2 nights @ RT
-4
-2
0
2
4
He
at
Flo
w (
mW
)
-50 0 50 100 150 200
Temperature (C)
1st Heat @ 10C/minCool @ 10C/min2nd Heat @ 10C/min
Exo Up Universal V4.3A TA Instruments
Curing reactions are kinetic in nature
128.29C0.5594W /g
122.26C323.9J/g
137.04C0.9506W /g
130.12C315.5J/g
149.93C1.972W /g
141.85C315.1J/g
160.93C3.431W /g
151.92C320.0J/g
172.86C5.792W /g
162.53C320.5J/g
-2
0
2
4
6
He
at F
low
T4 (
W/g
)
100 120 140 160 180 200 220 240
Temperature (C)
1C/m in2C/m in5C/m in10C/m in20C/m in
DSC Analysis of Polylactic Acid (PLA)
2000 25 50 75 100 125 150 175
Temperature (C)
0.4
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
Heat Flow (Normalized) (W/g)
Exo Up
Solid, rigid amorphous
Rubbery, amorphous
Glass Transition
Crystallization
Solid, crystalline
Melting
Liquid, amorphous
A modest cooling rate of 10C/min quenches PLA into its' amorphous phase
Melting is Not Heating Rate Dependent
Phenacetin
Hermetic Pan
Approx 1.5mg
Onset of melting shifts by 0.3C over heating rate range of 1-
20C/min for sample that has a true melt
Ciprofloxacin Hydrochloride Decomposes
Onset differs by almost 30C
Decomposition is kinetic (heating rate dependent)
TGA of Ciprofloxacin Hydrochloride
0.0
0.5
1.0
De
riv. W
eig
ht
(%/
C)
20
40
60
80
100
We
igh
t (%
)
0 50 100 150 200 250 300 350 400
Temperature (C)
Decomposition
DSC of Water
Cool Cycle
Heat Cycle
-10
0
10
20
30
40
Heat Flo
w (
W/g
)
-40 -30 -20 -10 0 10 20
Temperature (C)
Sample: Distilled, deionized waterSize: 5.0000 mg
Exo Up
Absorbed Moisture Acts as a Plasticizer
to Lower the Glass Transition of Sucrose
Tg of Dry Sucrose 68C
Implications for storage conditions
Summary - DSC
Differential Scanning Calorimetry determines transition temperatures, heat capacity, monitor reactions, and determine kinetics of processes
DSC, along with TGA, is widely used because of its ease of operation and small sample requirements
Most all technology based industries rely on DSC.
Discovery TGA Instruments
Discovery 5500 Discovery TGA
TGA 5500 DiscoveryTGA
TGA 55/550Q500/Q50
Temperature Range Ambient to 1200C
Ambient to 1200C
Ambient to 1000C
Isothermal Temperature Accuracy
1C 1C 1C
Heating Rate Range 0.1 to 500C/min (Linear)
>1600C/min(Ballistic)
0.1 to 500C/min (Linear)
>1600C/min(Ballistic)
0.1 to 100C/min (Linear)
Sample WeightCapacity
1000mg 750 mg 1000 mg
Dynamic WeighingRange
1000mg 100 mg 1000 mg
Baseline Dynamic Drift (50-1000C)
< 10 g 10 g
TGA Furnace Options
What is Thermogravimetric Analysis (TGA)?
Thermogravimetric Analysis (TGA) measures weight/mass change (loss or gain) and the rate of weight change as a function of temperature, time and atmosphere.
Measurements are used primarily to determine the composition of materials and to predict their thermal stability. The technique can characterize materials that exhibit weight loss or gain due to sorption/desorption of volatiles, decomposition, oxidation and reduction.
What TGA Can Tell You?
Thermal Stability of Materials
Oxidative Stability of Materials
Composition of Multi-component Systems
Estimated Lifetime of a Product
Decomposition Kinetics of Materials
The Effect of Reactive or Corrosive Atmosphereson Materials
Moisture and Volatiles Content of Materials
TGA Temperature Verification
Discovery TGA 5500 Baseline Performance
Tare reproducibility study Discovery 5500
50 1 2 3 4
Time (min)
10
-10
-6
-2
2
6
tare reproducibility test 1 CKK TGA 5500-0013 8172017
Tare reproducibility study Discovery 5500
50 1 2 3 4
Time (min)
10
-10
-6
-2
2
6
tare reproducibility test 2 CKK TGA 5500-0013 8172017
Tare reproducibility study Discovery 5500
50 1 2 3 4
Time (min)
10
-10
-6
-2
2
6
tare reproducibility test 3 CKK TGA 5500-0013 8172017
Tare reproducibility study Discovery 5500
50 1 2 3 4
Time (min)
10
-10
-6
-2
2
6
tare reproducibility test 4 CKK TGA 5500-0013 8172017
Tare reproducibility study Discovery 5500
50 1 2 3 4
Time (min)
10
-10
-6
-2
2
6
tare reproducibility test 5 CKK TGA 5500-0013 8172017
Tare reproducibility study Discovery 5500
Overlay
50 1 2 3 4
Time (min)
10
-10
-6
-2
2
6
2.449 g
-0.267 g
Q 500/50 Baseline Performance
26.87g
Q500 TGA w/ EGA Furnace @ 20C/minUsing Recommended Flowrates
Sample Purge 90ml/min of He
Balance Purge 90ml/min of He
60
70
80
90
Sa
mp
le P
urg
e F
low
(m
L/m
in)
0
10
20
30
40
50
Ba
lan
ce
Pu
rge
Flo
w (
mL
/min
)
-20
-10
0
10
20
We
igh
t (
g)
0 200 400 600 800 1000
Temperature (C)
Balance Purge 10ml/min of He
Calcium Oxalate Repeatability
0.0
0.6
[ ] D
eriv. W
eig
ht (%
/C
)
20
40
60
80
100
Weig
ht (%
)
0 200 400 600 800
Temperature (C)
Overlay of 8 runs, same conditions
Thermal Stability of Polymers
1: Gas 1 (N2)
2: Ramp 20C/min to 650C3: Gas 2 (air)
4: Ramp 20C/min to 1000C
Gas Switch
TGA of Drug A Monohydrate
4.946%(0.7505mg)
-2
0
2
4
6
Deriv. W
eig
ht (%
/min
)
80
85
90
95
100
105
Weig
ht (%
)
0 50 100 150 200 250 300
Temperature (C) Universal V3.4C TA Instruments
Sample: Drug A Monohydrate Size: 15.1740mg Heating Rate: 10C/min
Water weight loss
Decomposition
Higher heating rates increase the observed
decomposition temperature
0
20
40
60
80
100
We
igh
t (%
)
0 100 200 300 400 500 600
Temperature (C)
Polystyrene 20C/minPolystyrene 10C/minPolystyrene 5C/minPolystyrene 1C/min
Universal V4.2D TA Instruments
Sample Mass 10mg 1mg
High-Heating Rate TGA Analysis
60.09% Polypropylene(2.736mg)
0
20
40
60
80
100
Weig
ht (%
)
0 200 400 600 800 1000Temperature (C) Universal V3.9A TA Instruments
500 C/min40C/min
40% calcium
carbonate
High-Heating Rate TGA Analysis
Residue Determination - 0.2% Salt Solution
Residue:0.2212%(0.2160mg)
Method Log:1: Ramp 5.00 C/min to 90.00 C2: Isothermal for 120.00 min3: Ramp 5.00 C/min to 600.00 C4: End of method
0
20
40
60
80
100
Weig
ht (%
)
0 50 100 150 200 250
Time (min) Universal V3.2A TA Instruments
Sample: NaCl 0.2% in H2O Size: 97.6300mg
EVA Copolymer
16.87% Acetic Acid(3.240mg)
-20
0
20
40
60
80
100
120
Weig
ht (%
)
0 100 200 300 400 500 600 700
Temperature (C) Universal V3.3B TA Instruments
% Vinyl Acetate = % Acetic Acid * Molecular Weight(VA) / Molecular Weight (AA)
VA% = 16.85(86.1/60.1) = 24.2%
Sample: EVA (25%) Size: 19.2030mg Heating Rate: 10C/min
Effect of Flame Retardant
0 200 400 600 800
60
70
80
90
100
TEMPERATURE (C)
WE
IGH
T (%
)
Without Flame Retardant
With Flame
Retardant
Size: 20 mg
Prog.: 10C/min
Atm.: Air
Effect of DSC Pinhole pans on TGA resolution
14.90% (1.050mg)
4.830% (0.3405mg)
StandardTGA Pan
Pin HoleDSC Pan
0
1
2
[
] D
eriv. W
eig
ht (%
/C
)
55
65
75
85
95
105
Weig
ht (%
)
0 50 100 150 200 250
Temperature (C)
Gypsum
Theoretical: 15.69%
Theoretical: 5.23%
Summary - TGA
Thermogravimetric Analysis determines decomposition temperatures, rates of decomposition and volatilization, kinetics of weight loss, boiling points, vapor pressure, composition of multicomponent products and much more.
TGA, along with DSC, is widely used because of its ease of operation and small sample requirements
Most all technology based industries rely on TGA.
Simultaneous Differential
Thermal Analysis (SDT)
TA Instruments
Introducing the Discovery SDT 650
Discovery SDT 650
Features and Technology
Performance
Applications
Simultaneous DSC-TGA (SDT)
Simultaneous application of Differential Scanning Calorimetry (DSC) and Thermogravimetry (TGA) of a material will measure both heat flow and weight change as a function of time, temperature and atmosphere in a single experiment.
Simultaneous DSC-TGA (SDT)
Identical experimental
conditions maintained
DSC/TGA
Simplification of data
interpretation
Identical experimental DSC and TGA conditions:
Sample Mass
Heating Rate
Atmosphere (purge gas and flow rate)
Sample Crucible
Simplification of data interpretation
Is the sample weight stable during an endothermic or exothermic thermal event?
The complimentary information allows differentiation between endothermic and exothermic events which have no associated weight loss (melting and crystallization) and those which involve a weight change (volatilization, oxidation, degradation).
Discovery SDT 650
An excellent addition to the Discovery Thermal Suite
Discovery Series instrument features
Enhancements to technology
Best-in-class performance without
pre- and post- test
data manipulation
TGA-DSC Kaolin Clay
1010.42C
125.2J/g
548.10C
412.4J/g
199.23C
13.59J/g
1292.93C
13.96J/g
0.1
0.2
0.3
0.4
Deri
v.
Weig
ht (%
/C
)
90
100
110
120
We
ight (%
)
-4
-3
-2
-1
0
1
Heat F
low
(W
/g)
0 200 400 600 800 1000 1200 1400
Temperature (C)
DSC-TGA Sodium Tungstate
-2
1
4
7
Hea
t F
low
(W
/g)
-0.6
-0.3
0.0
0.3
0.6
0.9
Deriv. W
eig
ht (%
/C
)
60
66
72
78
84
90
96
102
We
ight (%
)
0 200 400 600 800
Temperature (C)
Small Sample Size (3mg) and 10C/min Heating Rate
Dehydration
Solid state and melting transitions
Dehydration Sensitivity
0.2078% (0.01795mg)
114.96C
1.094J/g
0.0055
0.0115
0.0175
0.0235
0.0295
0.0355
0.0415
Deri
v. W
eig
ht (%
/C
)
99.4543
99.7543
100.0543
100.3543
Weig
ht (%
)
-0.35
-0.30
-0.25
-0.20
Heat F
low
(W
/g)
40 60 80 100 120 140 160 180
Temperature (C)
DSC-TGA Gypsum
0.5
1.0
[
] D
eri
v. W
eig
ht (%
/C
)
-2.0
-1.5
-1.0
-0.5
0.0
[
] H
eat F
low
(W
/g)
60
70
80
90
100
Weig
ht (%
)
0 50 100 150 200 250 300
Temperature (C)
Alumina sample pans with lids and heated at 10C/min
TGA-DSC Soda Ash
857.18C
851.38C186.8J/g
0.1
0.2
Deri
v. W
eig
ht (%
/C
)
-8
-6
-4
-2
0
Heat F
low
(W
/g)
70
80
90
100
Weig
ht (%
)
0 200 400 600 800 1000 1200 1400
Temperature (C)
300 350 400 450 500 550 600
473.63C
314.87C16.62(24.57)J/g
350.90C
316.33C7.949J/g
Dehydration
Heat flow Integrations automatically normalized using weight at start of transition
Polymorphic phase transitions
Melting transition
Heat of Fusion Using Original Weight
468.7J/g
13.27mg
384.1J/g
11.27mg
324.7J/g
9.379mg
266.9J/g
7.628mg
207.7J/g
5.994mg
4
6
8
10
12
14
16
We
igh
t (m
g)
-12
-10
-8
-6
-4
-2
0
2
Hea
t F
low
(W
/g)
20 40 60 80 100 120 140
Time (min)
13.26mg Sodium Chloride
Significance of Normalized Weight
468.7J/g
13.27mg
459.1J/g
11.27mg
459.2J/g
9.379mg
464.4J/g
7.628mg
459.8J/g
5.994mg
468.7J/g 384.1J/g 324.7J/g 266.9J/g 207.7J/g
Heat of Fusion using Original W eight (13.26mg)
Heat of Fusion using W eight at Start of Integration
4
6
8
10
12
14
16
18
Weig
ht
(mg
)
-12
-10
-8
-6
-4
-2
0
2
He
at F
low
(W
/g)
20 40 60 80 100 120 140
Time (min)
Gold melting How many runs are shown here? Closest guess
wins a gift card:
Exo Up
31
Melting point measurements
Onset temperatureMean = 1063.99 C
SD = 0.07 C n = 31
True value = 1064.18 CDifference = 0.19 C
Enthalpy of fusion measurements
Enthalpy of fusionMean = 62.984 J/gSD = 0.16 J/gn = 31
True value = 64.50 J/gDifference = 1.52 J/g (2.3%)
Hi-ResTM TGA for Improved Resolution
EVA
Hi-Res TGA Ramp @ 50C/minStandard TGA Ramp @ 20C/min
SDT 650 Data Standard TGA Ramp vs Hi-Res TGA Ramp
Hi-ResTM TGA for Improved Resolution
EVA
Hi-Res TGA Ramp @ 50C/minStandard TGA Ramp @ 20C/min
SDT 650 Data Standard TGA Ramp vs Hi-Res TGA Ramp
Why Upgrade from the Q600 SDT?
Features and Function
Advance Features
MDSC for Cp
Hi-Res TGA for better separation
MTGA for kinetics
Better Performance
Lower weight drift
Improved gas handling
Better vacuum
Gas blending module
Reliable Automation
30-position autosampler
Automated calibrations & verifications
Dual Sample TGA
Features and Function
Innovative App-Style Touch Screen
Graphical design for enhanced usability
Information, status and great data just One-Touch-Away
Touch screen on all models
Easy quick change beams
Powerful TRIOS Software
5 year warranty on furnaces
Thank You
The World Leader in Thermal Analysis, Rheology, and Microcalorimetry
TA Instruments
Microcalorimeters
of Many Types
TA Instruments
Definition
Calorimetry (n) Measurement of the amount of heat evolved or absorbed in a chemical reaction, [biological process,] change of state or formation of a solution. American Heritage Dictionary
Modern Calorimeters
Differential Scanning Calorimeter (DSC)
Isothermal Titration Calorimeter (ITC)
Isothermal Microcalorimeter (IMC)
Combustion Calorimeter (Bomb Calorimeter)
Adiabatic Calorimeter
Hazards Calorimeter
Solution Calorimeter
Sorption Calorimeter
Respiratory Calorimeter
Animal Calorimeter .
Modern Microcalorimeters
Isothermal Microcalorimeter
Isothermal Titration CalorimeterDifferential Scanning Calorimeter
Differential Scanning Calorimeter Differential Scanning Calorimeter
Isothermal Microcalorimetry (IMC)
SensitiveMore
SensitiveW nW
3 samples1 reference
Sample Flexibility 1 mL sample Vol.
Temp Range: -40 to 150C1-48 samples
Sample Flexibility1-20 mL sample Vol.
Temp Range: 15 150C
MC DSC
TAM IV & TAM 48
Nano ITC
1 sampleMax Sensitivity
1 mL or 190 L cells Temp Range: 2 80C
mW
8 samples8 reference
20 mL sample Vol.Temp Range: 5 to 90C
TAM Air
Isothermal Microcalorimeters
General Purpose:
Thermal Activity Monitors (e.g. TAM IV, TAM 48, TAM AIR) are general purpose IMC which can be accessorized to study many different processes such as materials stability and compatibility, cement curing, heats of solution, pharmaceutical stability, and microbiological growth.
Specialized:
An isothermal titration calorimeter (ITC) is an IMC specifically designed to measure the heats of interaction when one liquid is titrated into another. ITC is used to study intermolecular binding, surfactant properties (e.g. micelles), and enzyme kinetics.
TAM Isothermal Microcalorimeter
TAM IV and 48 Configurations
Microcalorimetry A Universal Technique
Isothermal microcalorimetry is a technique for a direct measurement of heat production or consumption of a sample
Virtually all chemical, physical, and biological processes result in either heat production or heat consumption.
Calorimetry quantifies the amount and rate of heat release in terms of heat flow, heat and heat capacity.
Calorimetry is a non-specific technique making it ideal for studying almost all kind of biological, physical and chemical processes in life sciences, material sciences and within the pharmaceutical field.
TAM IV The Universal IMC
Amorphicityassessment
Microorganismdetection
TAM IV The Universal IMC
Material compatibility
Stability
TAM IV Flexibility in Size and Sensitivity
Sample size
Absolute Sensitivity
TAM IV Sample Handling Systems
The TAM IV offers a complete array of ampoules in two basic types; closed and open.
Closed, also referred to as static, ampoules contain the specimen in a static fashion: no manipulation of the sample is performed during the measurement.
Open ampoules are part of the micro reaction system for the direct manipulation or modification of the sample or its surroundings during the experiment.
Summary - Isothermal Microcalorimetry
Calorimetry is nondestructive and noninvasive
Monitor all kinds of processes:Chemical, Physical and Biological
Not dependent on the physical shape of the sample
Solids, liquids and gases can be studied
No chemical derivatization or immobilization
No need for sample preparation
Non-specific
Microcalorimetry continuously and directly measures the process under study - Real-time data
TAM Air
Isothermal Microcalorimetry
TA Instruments
Sensitive More Sensitive
W nW
TAM IV& TAM IV 48
mW
TAM Air
TAM Thermal Activity Monitors
4 150 C
Flexible one system multiple possibilities
Modular add functionality by choice of calorimeters, sample handling systems and accessories
Sample sizesfrom less than 1 mL up to 125 mL
4 channel version highest flexibility and sensitivity
48 channel versionhighest throughput
5 90 C
Flexible interchangeable calorimeter blocks depending on sample
Sample sizesfrom 20 mL up to 125 mL
3 channel version Large samples up to 125 mL
8 channel version Samples up to 20 mL Possibility to add and mix in situ
TAM Air IMC
TAM Air consists of a thermostat and a calorimeter
The air based thermostat precisely controls the calorimeter
temperature and minimize outside temperature disturbances.
The calorimeters are held together in a single removable block, with
either 8 or 3 individual calorimeters
Each calorimeter is a twin heat flow
calorimeter, consisting of a sample
and a reference side
Sample Handling
Static ampoules available in glass, HDPE plastic and stainless steel
Admix ampoule is available in 20 mL size with and without motor for stirring
Cement Hydration Process
I. Rapid initial process Dissolution of ions and initial hydration
II. Dormant period Associated with a low heat evolution and slow dissolution of silicates
III. Acceleration period Silicate hydration
IV. Retardation period Sulfate depletion and slowing down of the silicate hydration process
V. Long term reactions
He
at flo
w, m
W
Time, hours
Food Fermentation
Fermentation of
milk
beer &wine
cheese
pro-biotic foods
Calorimetry can be used to study the properties of microbial cultures such as
assess differences betweendifferent cultures
measure their doubling time
the influence of additives
the influence of temperature
Lars Wads: Milk Fermentation studied by Isothermal Calorimetry
TA Instruments AN 314-04
Power of TAM Air
Multi-sample capacity for simultaneous analysis
Eight- or three-channel true twin calorimeters each with low noise, high sensitivity and excellent long term stability
Easy and robust operation
TAM Air 8 and 3 channel calorimeter can easily be exchanged depending on sample needs
Sample flexibility with a choice of ampoule configurations
Increased measurement specificity with external probes
Isothermal Titration
Calorimetry
TA Instruments
Isothermal Microcalorimetry
SensitiveMore
SensitiveW nW
3 samples1 reference
Sample Flexibility 1 mL sample Vol.
Temp Range: -40 to 150C1-48 samples
Sample Flexibility1-20 mL sample Vol.
Temp Range: 15 150C
MC DSC
TAM IV & TAM 48
Nano ITC
1 sampleMax Sensitivity
1 mL or 190 L cells Temp Range: 2 80C
mW
8 samples8 reference
20 mL sample Vol.Temp Range: 5 to 90C
TAM Air
Excellent!!
Nano ITC
Isothermal Titration Calorimetry (ITC)
ITC is recognized as Gold Std technique for measuring molecular binding reactions
Only technique that gives full thermodynamic profile of a molecular binding reaction in one experiment
Enthalpy - HEntropy - SStoichiometry n
Nano ITC offers maximum flexibilityNano ITC Standard Volume - 1.0 ml sample cell volumeNano ITC Low Volume - 190 L sample cell volume
Affinity ITC technology is the most advanced on the marketTrue power compensation ITCBoth Affinity ITC SV and LV instruments are newest technology
Isothermal Titration Calorimetry - Basics
Experiment:
Mix two solutions
Measure the Heat (H)
Analyze heat changes using an assumed model
G = -RTlnKa = H-TS
Calculate:
Kd, G, S, stoichiometry
Cp, [H+], Km, kcat, Ki
Rationalize:
-Change in biomolecular structure
-Lead optimization
-Change due to Mutant Activities
HITCn
KITC
Affinity ITC and Affinity ITC Auto
Innovative advancement of ITC hardwareField upgradeable to fully automated configurationReliable & robust autosampler for unattended ITC operationPerformance is unmatched by any other ITCEasy user selectable manual sample loading without disconnecting autosampler or reconfiguring instrument
Easy sample reclamation from cell and injection syringeHighest quality ITC data obtained with every titrationEasy-to-use, powerful software featuresMaximum productivity for any molecular interaction analysis
New Mixing technology!
Scanning Microcalorimetry
SensitiveMore
SensitiveW nW
3 samples1 reference
Sample Flexibility 1 mL sample Vol.
Scan Rate: 0 - 2C/min
1 sample1 reference
In-solution sample300 L active cell Vol.
Scan Rate: 0.001 - 2C/minAutomated sample handling
MC DSC
Nano DSC
mW
Discovery DSC
Diffusion-bonded SensorAutosampler
Sample Size: up to 20 mgScan Rate: 0.1 100C/min
Nano DSC Instruments
Unmatched performance of any DSC instrument
Newest DSC technology
Reduced manufacturing/delivery time
Improved field serviceability
Nano DSC Nano DSC A/S Interface Nano DSC A/S System
Nano DSC Nano DSC A/S Interface Nano DSC A/S System
Nano DSC Design
Nano DSC Platinum capillary cells USB connection to computer Innovative sensor design Superior sensitivity
Nano DSC Sensitivity
Nano DSC of IgG and CH2 Variants
Tmax
(C)
Hcal
(kJ/mol)
Scal
(kJ/molK)
mutA 57.1 570 1.7
mutB 57.6 669 2.0
WT 64.9 529 1.6
IgG control (red)Mutated #A (green)Mutated #B (blue)
Nano DSC Autosampler System Advantages
Maximum flexibility
Fixed capillary cell with unmatched sensitivity
Smallest active sample cell volume for any fixed cell DSC
Nano DSC sensitivity is the best on the market
Ease-of-use is unmatched: Sample loading, cell cleaning, Autosampler
Complete suite of data acquisition and analysis tools
Nano DSC is used in a wide variety of application
Multi-Cell Differential Scanning
Calorimetry (MC-DSC)
TA Instruments
Multi-Cell Differential Scanning Calorimetry
Phase Transitions in Foods
Annealing of Rice
Amorphous vs. Crystallinity
The presence of imperfections (amorphicity) in a crystal affect relevant properties.
Properties affected are: chemical stability, solubility, bioavailability, surface energy.
To have a material well characterized it is very important to have a good control over these key properties.
Relevance of Crystallinity
Calorimetry Summary
A universal technique used in many industries
Many types of calorimeters for different applications
TA Instruments has the widest line of calorimeters
Types of calorimeters:
TAM and TAM-AIR IMC
Isothermal Titration Calorimeters (ITC)
Differential Scanning Calorimeter (DSC)
Multi-Cell Differential Scanning Calorimeter
Solution Calorimeter
Sorption Calorimeter
What Does TA Instruments Make?
Differential Scanning Calorimeters
Thermogravimetric Analyzers
Simultaneous Differential Thermal Analyzers
Microcalorimeters of many types
Dilatometers and Thermomechanical Analyzers
Thermal Diffusivity
Thermal Conductivity
Mechanical Testers
Dynamic Mechanical Analyzers
Rotational Rheometers
Rubber Rheometers
Dilatometers and
Thermomechanical Analyzers
TA Instruments
Dilatometer Products from TA Instruments
Dilatometry is a technique that measures change in length, sample temperature and furnace temperature to facilitate the measurement of the coefficient of thermal expansion (CTE), softening point, determination of phase and glass transitions.
Horizontal Dilatometers
DIL 801/801L
Air/Inert Gas/Vacuum
Horizontal Dilatometers
DIL 802/802L
Air/Inert Gas/Vacuum
Horizontal Dilatometers
DIL 803/803L
Air/Inert Gas/Vacuum
Optical Dilatometer DIL 806
Temperature range;
-160C up to 700C
RTC up to 1000C or 1400C
Resolution: 50nm, 0.1C
Accuracy: 0.05 x10-6 K-1
Atmosphere: inert gas, vacuum, air
Sample Height: max 10 mm
Sample Length: max 29 mm
Principal of DIL 806
L
L: length change
C: interval of the CCD pixel
N: the number of CCD pixels of two sample-edges
M: magnification of the optical system
Sample
Furnace
Light SourceCCD Detector
Telecentric Optical System
Thermomechanical Analysis
Thermo-mechanical Analysis measures changes in the dimensions of a sample as a function of time, temperature and force in a controlled atmosphere.
TMA can measure Coefficient of Thermal Expansion (CTE),along with transitions such as the glass transition (Tg).
Advance TMA allows for viscoelastic measurements.
Expansion of a Printed Circuit Board
0 20 40 60 80 100 120 140 160 180 200 220
-10
0
10
20
30
40
50
60
Temperature (C)
Dim
en
sio
n C
ha
ng
e (
m
)
Tg
128.92C
= 40.7mm/mC
= 160mm/mC
What Does TA Instruments Make?
Differential Scanning Calorimeters
Thermogravimetric Analyzers
Simultaneous Differential Thermal Analyzers
Microcalorimeters of many types
Dilatometers and Thermomechanical Analyzers
Thermal Diffusivity
Thermal Conductivity
Mechanical Testers
Dynamic Mechanical Analyzers
Rotational Rheometers
Rubber Rheometers
Thermal Diffusivity and
Thermal Conductivity
TA Instruments
What is Thermal Conductivity?
The ability of a material to transport heat along a linear dimension in response to a temperature difference along the same direction (measured in W/mK or Btu in/h ft2F).
Characterized by Fouriers Heat Equation
LT
AQK
=
/
/
Thermal Conductivity Ranges
F.P. Incropera and D.P. DeWitt: Fundamentals of Heat and Mass Transfer, 5th Ed., Willey, NY 2002
Fox Heat Flow Meters
Fox 200 Fox 314 Fox 600
Fox 800
Available Features
Vacuum down to 10-9 Torr
Autosampler for higher throughput
Subambient capabilities
Specific heat measurement capabilities
Rotational Systems
Tuber100
Thermoconductivity Meters
DTC25 DTC300
Fox50
What is Thermal Diffusivity?
Thermal diffusivity is the thermophysical property that defines the speed of heat propagation by conduction during changes of temperature. The higher the thermal diffusivity, the faster the heat propagation. The thermal diffusivity is related to the thermal conductivity, specific heat capacity and density.
pC
=Thermal Diffusivity
Density Specific heat capacity
Thermal Conductivity
Flash Diffusivity Instrumentation
Discovery Xenon/Laser Flash
Discovery Laser
Flash
Flash Diffusivity Method
T0 + T
L
Thermogram in Flash Diffusivity
2
1/2
L = 0.1388
t
t1/2
Parkers Relationship
Where:
= thermal diffusivityL = sample thickness
Flash Diffusivity Measurements
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
30 50 100 200 300 400 500 600 700 800 900 1000
Th
erm
al
Dif
fusi
vit
y (
cm2.s
-1)
Temperature (C)
Literature Values
Laser source
Xenon source
Graphite Reference Material NIST SRM 8425
Dynamic Range of Thermal Conductivity
Thank You
The World Leader in Thermal Analysis, Rheology, and Microcalorimetry
TA Instruments
