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Leading Thermal Analysis

Analyzing & Testing

Thermogravimetric Analysis TGAMethod, Technique, Applications

TG 209 F1

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Thermo-Microbalance TG 209 F1 Libra

Thermogravimetry (TG) or

Thermogravimetric Analysis (TGA)

is a well proven Thermal Analysis

method. TGA is used in the research &

development o various substances and

engineering materials solid or liquid in order to obtain knowledge about

their thermal stability and composition.

In recent decades, TGA has been used

increasingly or the quality control

and assurance o raw materials and

incoming goods as well as or ailure

analysis o nished parts, especially

in the polymer processing industry.

Various international standards describe

the general principles o thermogra-

vimetry or polymers (ISO 11358) or

other specic applications, such as

TGA Method

compositional analysis or rubber

(ASTM D6370) and evaporation loss o

lubricating oils (ASTM D6375).

NETZSCH Analyzing & Testing has been

manuacturing thermo-microbalancesor many years. Our vertical, top-loading

design not only provides or easy

operation and sample loading, but

also allows gases to fow naturally

in an upward direction. Evolved gas

analyzers such as mass spectrometers,

FT-IR spectrometers and/or GC-MS (gas

chromatograph-mass spectrometers)

can then be coupled directly at the

top o the unit. The automatic sample

changer (ASC) can also be used to

conduct routine measurements around

the clock.

Measuring Principle

A thermobalance is used to measure the

mass change o a sample as a unction

o temperature or time, under a denedand controlled environment with respect

to heating rate, gas atmosphere, fow

rate, crucible type, etc.

Thermocouple

Sample carrier

Compensation

Balance

Furnace

Sample

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This TGA plot shows the decomposition

o calcium oxalate monohydrate,

CaC2O4 * H2O, in air at a heating rate o

10 K/min. The decomposition occurs in

three mass loss steps with the release o

water (12.3%), carbon monoxide(19.2%) and carbon dioxide (30.1%).

The corresponding 1st derivative o

the TGA curve, DTG, provides the

decomposition rate and is helpul

or evaluating the mass loss steps

accurately.

Measurement Result

TG 209 F1 Libra with automatic sample changer (ASC)

TGA and DTG curves or the decomposition o calcium oxalate monohydrate

At a Glance

BeFlat: Automatic baseline

correction

c-DTA: Caloric eects made

visible

Corrosion-resistant ceramic

urnance

Vacuum-tight design

Precise ultra-microbalance

Vertical, top-loading design

Coupling to evolved gas analysis

Automatic sample changer (ASC)

or up to 64 samples

Integrated gas supply unit with 3

mass fow controllers

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TG 209 F1 Libra Trendsetting Technology

Sae and Easy Handling

One advantage o the TG 209 F1Libra

is its vertical, top-loading design which

guarantees ree and sae access to the

crucible there is no hang-down wire

with any danger o bending, and no

horizontal beam where crashing can

occur. When placing the crucible on the

sample carrier, there is no eect to the

microbalance since the sample carrier is

detached by an automatic liting device.

Sample placement is thereore always

trouble-ree.

High Temperature and Fast Heating

Rates in a Ceramic Furnace

The maximum temperature o the

corrosion-resistant micrournace

amounts to 1100C (sample

temperature). Its high heating rates

o up to 200 K/min are suited or

identiying the material by a ast QC

check. A water-cooled jacket provides

the micro-urnace with ast cooling

and thereore allows or high sample

throughput.

High Stability under Thermostatic

Control

The precise ultra-microbalance under

thermostatic control provides high

resolution o 0.1 g in the large mass

measurement range o 2000 mg.

Samples with a large mass change

can be continuously analyzed at a

high precision level without switching

measurement ranges.

c-DTA or additional inormation

on caloric eects

The sample carrier type P (Platinel)

provides the highest sensitivity or

the c-DTA signal, which serves orrecording endothermal and exothermal

eects via calculated DTA in a manner

similar to DSC (Dierential Scanning

Calorimetry).

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Defned Gas Conditions or

Reproducible Measurements

The vacuum-tight design allows a pure

and dened inert gas atmosphere to

be established or the pyrolysis o the

sample. No superimposed oxidation by

residual air can occur. The integrated gas

supply unit with mass fow controllers

(MFCs) accommodate two purge gasesand one protective gas. The MFCs can

be controlled, recorded and evaluated

via the sotware. Gas switching can

be implemented automatically under

reproducible conditions.

AutoVacTM and Vacuum Technique

or More Accurate and Reproducible

Results

The optionalAutoVacTM eature or

programmable automatic evacuation and

gas lling provides uniorm measurement

conditions and thereore ensures

reproducible TGA results. When polymer

mixtures or blends are measured in a

vacuum, the boiling point depression o

low volatiles (e.g., solvents or plasticizers)

can be realized. A better separation

rom the decomposition o the polymercomponent can be achieved.

Technical Specifcations

Temperature range (10C) 20C to 1100C

Heating and cooling rates 0.001 K/min to 200 K/min

Cooling time (1100C to 100C) 12 min

Measuring range 2000 mg

Resolution 0.1 g

Atmospheres inert, oxidizing, static, dynamic

Vacuum-tight design

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Application Material o the sample support Sensor type For crucible types

Standard TGA Al2O3 Type P 6.7 mm to 9 mm diameter, 85 l to 350 l

Ideal or c-DTA PdPt/Au/AuPd (Platinel) Type P (disk) 6.7 mm to 9 mm diameter, 85 l to 350 l

For corrosive media Al2O3 Type P, protected 6.7 mm to 9 mm diameter, 85 l to 350 l

2 For ASC: max. diameter o the crucible is 8 mm

Exchangeable Sample Carrier Types2

Application Material Diameter/Height Volume

Standard TGA tests, not or salts and glass Al2O3 6.8 mm/4 mm 85 l

Standard TGA tests, not or salts and glass, high sample input Al2O3 8.0 mm/8 mm 300 l

Standard TGA tests, not or salts and glass, higher sample input Al2O3 9.0 mm/7 mm 350 l

Especially or c-DTA,not or metals Pt/Rh (80/20) 6.8 mm/2.7 mm 85 l

Especially or c-DTA,high volume, not or metals Pt/Rh (80/20) 6.8 mm/6 mm 190 l

Especially or c-DTA, up to max. 600C Al (99.5%) 6.7 mm/2.7 mm 85 l

1 For special applications, there are also crucibles available in other materials

Crucible Types or Various Applications1

Sample carrier type P, standard sample carrierand radiation shield or corrosive media

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Proteus Sotware or TG 209 F1 Libra User-Friendly and Versatile

The TG 209 F1Libra runs under

the versatile Proteus sotware on

a Windows operating system. The

Proteus sotware includes everything

you need to carry out a reliable

measurement and evaluate the resulting

data or even carry out complicated

analyses. The Proteus sotware is

licensed with the instrument and can

also be installed on other computersystems.

General Sotware Features

For Windows XP and Windows 7

operation systems

Multi-tasking or simultaneous

measurement and evaluation

Multi-moduling or up to 4 dierent

instruments

Multi-method analysis or curve

comparison and evaluation o variousmethods

Snapshot or on-line evaluation o

the running measurement

Picture-in-picture presentation

(PIP and FLIP)

Graphic and data export

Storage and restoration o analyses

Context-sensitive help system

Macro recorder

Main TGA Features

Mass change in % or mg

Automatic evaluation o mass change

steps and characteristic temperatures

Extrapolated onset and endset

Peak temperatures and values o the

1st and 2nd derivatives

Multi-point temperature calibration

via c-DTA

(calculated DTA signal) c-DTA or evaluation o endothermal

and exothermal eects

Automatic correction o buoyancy

and drit or rapid TGA results

Feature Advantage Beneft

c-DTACalculated DTA or endothermal and exothermal

eects

Better curve interpretation through a DSC-like

signal

Super-Res Rate-controlled mass changeBetter resolution and better separation o

superimposed mass change steps

Peak SeparationSeparation o DTG peaks which are in close

proximity

Better quantitative determination o superimposed

mass change steps

Thermokinetics

Accurate process prediction such as lietime and

decomposition behavior via multivariate non-linear regression

Process optimization through reely selectable time/temperature programs saves time and costs

Key Advanced Sotware Features

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User interace o the Proteus sotware duringevaluation:

Presentation o the TGA curve (black) together with

the DTG curve (blue, dashed line), the c-DTA curve(red) and two gas fow curves (blue, dotted line andgreen, dashed line) in the main rame

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TG 209 F1 Libra Smart Tools Integrated

The Intelligent TGA BeFlat or Automatic Correction o External Infuences

No More Baseline Run Faster to

Your Results

In order to ensure correct mass change

values, a baseline run is usually carried

out under identical test conditionssuch as heating rate, gas type, gas

fow rate, crucible type and geometry,

etc., and subtracted rom the sample

measurement. The baseline takes

instrument and buoyancy infuences into

consideration.

In contrast, the TG 209 F1Libra

generally no longer requires a separate

baseline run. This greatly simplies

routine test work, especially or quality

control in industry.

The Libra takes the physics behind the

external infuences into consideration

and corrects these eects automatically

(depicted in the graphic above). The

sotware stores the BeFlat data as well

as the raw data.

The adjacent gure depicts the water

loss in a sample rom 50C to 250C.

The green curve represents data with a

conventional correction by a separate

baseline run; the blue curve represents

the automatic BeFlat corrected dataand the results show a very good

congruence.

Stable baseline (blue) due to automatic correction o external infuences

Water loss in a sample

with BeFlat

classical baseline

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0,4

0,2

0,0

-0,2

-0,4

-0,6

-0,8

-1,0

-1,2

TGA measurement on Kaolinite; common presentation o the TGA curve (black),

the DTG curve (blue, dashed line) and the c-DTA curve (red)

c-DTA eects o several materials suitable or temperature calibration

Calculated DTA or Endothermal and Exothermal Eects

More Inormation through

Caloric Eects

In addition to the TGA and DTG

curves, this plot depicts endothermal

and exothermal eects determined bymeans o the calculated DTA signal,

c-DTA. Kaolinite (sample mass:

37.17 mg) was heated to 1100C in

a nitrogen atmosphere at 10 K/min.

The two endothermal c-DTA peaks

(198C and 535C) are directly related

to the occurring mass loss steps and are

caused by dehydration and dehydrox-

ylation: loss o adsorbed water rom the

surace (0.3%) and loss o water rom

inter layers (10.6%). The exothermal

c-DTA peak at 999C represents the

ormation o mullite.

Easy and Reliable Temperature

Calibration

The multi-point temperature calibration

executed by means o c-DTA conorms

to standardized methods, and can

thereore be easily validated. The onset

temperatures o the melting o highly

pure reerence metals are taken over

a broad temperature range. This plotshows the melting o In, Sn, Zn, Al and

Au as well as the solid-solid transition o

BaCO3 at a heating rate o 10 K/min.

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50 150 250 350 450

Temperature/C

-2.25

-1.75

-1.25

-0.75

-0.25

dMass/dt/(%/min)

TG 209 F1 Libra Advanced Sotware

Peak Separation or Better Accuracy

o Mass Change Steps

By applying Peak Separation to DTG

peaks, the quantitative mass loss steps

during material decomposition can

be separated much more clearly. The

ollowing plot shows the TGA result

on a rubber mixture (NR/SBR) or tires,

measured under vacuum (approx.

10-2 mbar). The symbols depict the

measured raw data, the colored lines

represent the separated peaks and the

solid black line is the cumulative curve

o the colored ones. The three separated

mass loss steps were 34.1%, 22.3%and 43.6%.

Super-Res or Event-Based TGA

Normally, a dened constant heating

rate is applied to the sample in order

to study its decomposition behavior.

Super-Res

provides a rate-controlledheating rate according to dened

thresholds with respect to the mass loss

rate (DTG curve) set by the operator.

This oten results in much better

separation o overlapping mass losssteps.

Good agreement between the experimetal data (symbols) and the cumulative curve (black) o the calculated

peaks (colored) as a result o applying Peak Separation

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150 250 350 450 550

Temperature/C

30

50

70

90

Mass/%

A B C D E1 2 3 4

0 10 20 30 40 50 60

Time/min

50

60

70

80

90

100

Mass/%

50

100

150

200

250

300

Temperature/C

Thermokinetics or the Optimization o any Process

With the unique NETZSCH

Thermokinetics sotware, any

process can be modeled. The kinetic

parameters such as activation energy,

pre-exponential actor and order o

reaction can be determined.

The TGA plot presents a biomass sample

measured at 4 dierent heating rates

rom 5 K/min to 40 K/min in an inert

gas atmosphere. The higher the heating

rate, the more the curves are shited

to higher temperature values. This is

typical behavior or eects caused by

kinetic processes. There is an excellent

congruence between the TGA raw data

(symbols) and the calculated curves

(solid lines). The ormal model used

consists o our consecutive reactions.

For the rst one, a 3-dimensional

diusion type was selected; the other

three are n-th order reactions.

Based on this model, a prediction was

computed: Starting at 30C, heating

to 300C at a heating rate o

150 K/min, and then holding the

temperature constant at 300C or

1 hour yields the blue mass change

curve shown here. The calculation

orecasts a residual mass o about45% ater 62 minutes.

Comparison o the TGA raw data (symbols) and the curves (solid lines)calculated on the basis o a 4-step reaction model

Prediction o the mass change or a temperature program including heating at

150 K/min to 300C, ollowed by an isothermal step (60 minutes)

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TG 209 F1 Libra or a Wide Variety o Applications

Polyamide

Polyamide 66 is a thermoplastic polymer

which is used or a wide variety o

technical parts. The stiness o the PA66

can be increased by suitable llers such as

glass bers. By means o TGA, not only

can the decomposition o the polymer be

determined, but the precise glass ber

content as well. The TGA curve also showsthe content o pyrolytic soot and added

carbon black.

NR/SBR Rubber

The TGA analysis on rubber is a standard

analytical method or the determination

o plasticizer content and rubber

components. The example shows an

NR/SBR rubber mixture which exhibits a

plasticizer content o 12.4%. The two-step

decomposition o the rubber (NR and SBR)

can be separated precisely. This compound

also has a chalk content as inorganic ller.

By switching to an oxidizing atmosphere

at 850C, the burning o the carbon black

could be observed.

SEBS+PP

Thermoplastic elastomers are a class ocopolymers or polymer mixtures with both

thermoplastic and elastomeric properties.

They can be used very easily in the

manuacturing process, e.g., by injection

molding. For investigating the plasticizer

content, the advantage o conducting the

TGA analysis under vacuum conditions

is evident (blue curves). By reducing the

vapor pressure o the plasticizer, two mass

loss steps were clearly separated.

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Magnesium Stearate

Commercially available magnesium

stearate, a widely used excipient or

pharmaceutical ormulations, is a mix o

several atty acid salts that may vary in

proportion. The magnesium stearate used

in the present study shows three mass-loss

steps o 0.5%, 1.1% and 2.1% in the

temperature range up to 180C. In thecorresponding TGA-FT-IR experiment (not

shown here), it was possible to identiy all

volatile components as water.

Coal

Coal pyrolysis is a complex process

involving a large number o chemical

reactions. During heating, mainly

volatiles (gases and tars) and solid

carbon (coke) are produced. 10 mg

o coal was measured in a nitrogen

atmosphere at a heating rate o

100 K/min. The rst mass loss (below

210C) can be most probably related

to the release o moisture; while the

other steps are mainly related to

organic volatiles.

Mica

The TGA analysis on mica shows mass

loss steps at lower temperatures or the

dehydration and the dehydroxylation o

the material. In addition, a characteristic

mass loss step can be observed at

1093C. It is the new ceramic urnace

o the TG 209 F1Libra, which permits

measurements up to 1100C, that

makes this mass-loss step experimentally

accessible.

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TG 209 F1 Libra with Evolved Gas Analysis (EGA)

By coupling TG 209 F1 Libra to a

gas analysis technique such as an

FT-IR (Fourier Transorm Inrared)

spectrometer, MS (Mass Spectrometer),

or GC-MS (Gas Chromatograph Mass

Spectrometer), inormation regardingthe type o evolved gases as a unction

o time or temperature can be obtained,

which yields a ngerprint o the

analyzed material.

Coupling to GC-MS

GC (Gas Chromatography) is a

high-resolution method or separating

volatile and semi-volatile compounds.

The gas mixtures are separated based

on the dierences in component

distribution between a stationary phase(e.g., inner coating o a capillary) and a

mobile phase (purge gas). This leads to

dierent time delays or retention times

o the gas components.

Dierent Methods

Evaluation o GC-MS-TIC chromatograms

Event-controlled TG-GC-MS measurement on NR/SBR versus continuous heating

MS (Mass Spectrometry) is applied as a

highly sensitive detection system at the

outlet o the GC separation column and

will register the time distribution o the

separated gas components in the purge

gas fow.GC-MS provides detailed structural

inormation on most compounds or

an accurate identication o the gas

components.

Additional Inormation

www.netzsch.com/gcms

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Detailed diagram o the unctional elements o the TGA-GC-MS coupling

MSD

1.6 u to 1050 u

GC

35C to 425C

Adapter and transer lineRT to 300C

TG 209 F1 Libra

10C to 1100C, 0.1 g

transer line

bypass

adapter

micro urnace

sample

sample carrier

TGA cell

sample loop

TGA sample gasoutlet (pump)

GC carriergas inlet

(He 5 bar)

valve

on o

JAS UNIS 500injector system

JASvalvebox

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TG 209 F1 Libra with Evolved Gas Analysis (EGA)

Coupling to MS

High-level material research and

characterization can be achieved by

coupling the TG 209 F1 Libra to our

QMS 403Aolos quadrupole mass

spectrometer. Any gases evolved are

introduced directly into the electron

impact ion source o the MS through a

quartz glass capillary heated to 300C.

Coupling to FT-IR

More than just the sum o its parts

is the motto or our comprehensive

coupling system incorporating an

FT-IR (Fourier Transorm Inrared)

spectrometer manuactured by

our cooperation partner, Bruker

Optics. The purge gas fow rom the

TGA carries the volatiles througha short heated transer line to the

vacuum-tight gas cell o the FT-IR. All

evolved gases with a changing dipole

moment are identied by their typical

absorption spectrum, and complex

gas mixtures can be spectroscopically

separated.

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Simultaneous TGA-MS-FT-IR

Coupling and PulseTA

The unique heated coupling adapter

allows simultaneous TGA-MS-FT-IR

measurements, even when the

automatic sample changer (ASC) is

running. Only one operational sotware

package on a single PC is needed

or TGA-MS-FT-IR. Comprehensive

evaluations can be displayed in one plot.Calibration and quantication o

the evolved gas components can be

achieved by the sophisticated PulseTA

technique.

Take advantage o nearly 40 years o

coupling experience and ask or our

special coupling brochures.Comprehensive evaluation o TGA, DTG, FT-IR (Gram-Schmidt), and QMS (u) versus temperature

Coupling o TENSOR 27, external gas cell, TG 209 F1 Libra and QMS 403 CAolos

Additional Inormation

www.netzsch.com/tir

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www.netzsch.com

NETZSCH-Gertebau GmbH

Wittelsbacherstrae 42

95100 Selb

Germany

Tel.: +49 9287 881-0

Fax: +49 9287 881 505

at@netzsch com

The NETZSCH Group is an owner-managed, internationally operating technology

company headquartered in Germany.

The three Business Units Analyzing & Testing, Grinding & Dispersing and Pumps &

Systems provide tailored solutions or highest-level needs. Over 2,500 employees

at 130 sales and production centers in 23 countries across the globe guarantee that

expert service is never ar rom our customers.

When it comes to Thermal Analysis, Adiabatic Reaction Calorimetry and thedetermination o Thermophysical Properties, NETZSCH has it covered. Our 50 years

o applications experience, broad state-o-the-art product line and comprehensive

service oerings ensure that our solutions will not only meet your every requirement

but also exceed your every expectation.