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By: Ellen kay R.Cacatian

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thermo analytic technique similar to (DSC)

technique for recording difference in temperaturebetween a substance & a reference material

changes as a function of temperature or time, result inexothermic or endothermic reactions

Same as in DSC, it monitors the reactions in materials

as a function of temperature Can analyze solid ( foil, powder, crystal or granular form)

and liquid

Small sample (10-20 mg)

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The areaA on the curve is proportional to the

heat ofthe reaction:

The constant K comprises manyfactors,

including the thermal properties ofthesam

ple, an

d varies with tem

perature.

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Specimens Sample Holder Reference Holder Specimen-holder Assembly Block Record Base Line

Peak Endothermic Peak Exothermic Peak Peak Width

Extrapolated Onset

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1. Sample holder comprising

thermocouples, containers & ceramic or

metallic block

2. Furnace

3. Temperature programmer

4. Recording system

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melting, phase transition

glass transition, evaporation

boiling, oxidation, decomposition

Cp temperature function , Cooling

crystallization

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provide a stable and sufficiently large hot

zone

must be able to respond rapidly tocommands from the temperature

programmer

The recording system must have a low

inertia to faithfully reproduce variations in

the experimental

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Ensure that the thermocouple & container are

consistently located with respect to each other

Care is necessary in selecting the experimental

parameters environment, composition, size and

surface volume ratio

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can be used at very high temperature

highly sensitive

flexibility in sample volume/form

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uncertaintyofheats offusion and transition

temperature

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1. Thermal properties

2. Phase changes

3. Finger print for identification purposes

4. Selection, comparison and end-use

performance of materials in research ,

quality control & production application.

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Pharmaceutical and food industries

cement chemistry, mineralogical research& in environmental studies

DTA curves may also be used to date

bone remains to study archaeological

materials

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In todays market most manufactures no

longer make a true DTA but rather have

incorporated this technology into

a Thermo gravimetric analysis (TGA),

which provides both mass loss and

thermal information.

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http://physicalchemistryresources.com/Book5_sections/TA_Differential%20

Thermal%20AnalysisHTML_1.htm

http://old.iupac.org/publications/analytical_compendium/Cha05sec2.pdf

http://www.anasys.co.uk/library/dsc1.htm