08-11-2012, 05:33 PM
Differential Scanning Calorimetry (DSC)
[attachment=38648]
What Can You Measure with DSC?
Qualitative analysis
Fingerprinting of minerals, clays, polymers
Sample purity
Melting points
Heat capacity, cp
Glass transition temperature, Tg
Crystallization temperature, Tc
Phase diagrams
Variants of DSC
Heat flux
1955 Boersma
1 large (30 – 100 g) furnace
Power compensated
Separate small (1 g) microheaters for sample and reference
Hyper DSC
Very fast scan rates 500°C/min
Mimic processing conditions
StepScan DSC
Short dynamic and isothermal scan steps
Separate reversible and irreversible effects
Melting
Negative peak on thermogram
Ordered to disordered transition
Tm, melting temperature
NB: melting happens to crystalline polymers; glassing happens to amorphous polymers
Activation Energy (Ea)
In 1889 Swedish scientist Svante Arrhenius
Minimum energy required to start chemical reaction
Unit for activation energy is kJ/mole
Height of potential barrier or energy barrier
[attachment=38648]
What Can You Measure with DSC?
Qualitative analysis
Fingerprinting of minerals, clays, polymers
Sample purity
Melting points
Heat capacity, cp
Glass transition temperature, Tg
Crystallization temperature, Tc
Phase diagrams
Variants of DSC
Heat flux
1955 Boersma
1 large (30 – 100 g) furnace
Power compensated
Separate small (1 g) microheaters for sample and reference
Hyper DSC
Very fast scan rates 500°C/min
Mimic processing conditions
StepScan DSC
Short dynamic and isothermal scan steps
Separate reversible and irreversible effects
Melting
Negative peak on thermogram
Ordered to disordered transition
Tm, melting temperature
NB: melting happens to crystalline polymers; glassing happens to amorphous polymers
Activation Energy (Ea)
In 1889 Swedish scientist Svante Arrhenius
Minimum energy required to start chemical reaction
Unit for activation energy is kJ/mole
Height of potential barrier or energy barrier