Differential Scanning Calorimetry (DSC)

Differential Scanning Calorimetry (DSC) measures the temperatures and heat flows associated with transitions in materials as a function of time and temperature in a controlled atmosphere. These measurements provide quantitative and qualitative information about physical and chemical changes that involve endothermic or exothermic processes, or changes in heat capacity.

The Glass Transition is the reversible change of the amorphous region of a polymer from a hard or brittle state to a viscous or rubbery condition.

The Glass Transition Temperature is a temperature taken to represent the temperature range over which the glass transition takes place.

What Affects the Glass Transition?

·         Heating Rate Crystalline Content

·         Heating & Cooling Copolymers

·         Aging Side Chains

·         Molecular Weight Polymer Backbone

·         Plasticizer Hydrogen Bonding

·         Filler

What information does thermal analysis by Differential Scanning Calorimetry (DSC) provide?

·         Analysis of Complex Transitions

·         Glass transition temperatures

·         Melting points and boiling points

·         Crystallization time and temperature

·         Percent Crystallinity

·         Heats of fusion and reaction

·         Heat Capacity

·         Specific heat

·         Oxidative stability

·         Rate of cure

·         Degree of cure

·         Reaction  kinetics

·         Isothermal curing

·         Purity

·         Thermal stability

·         Thermal Conductivity

ASTM procedures used for DSC testing of plastic:

ASTM E 1269  Determining Specific Heat Capacity by Differential Scanning Calorimetry.

ASTM D 3417 Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry (DSC).

ASTM D 3418  Transition Temperatures of Polymers By Differential Scanning Calorimetry.

This test method covers determination of transition temperatures, melt and crystallization of polymers by differential scanning calorimetry. The normal operating temperature range is from -50°C to 350°C

ASTM D 3895  Oxidative-Induction Time of Polyolefins by Differential Scanning Calorimetry

This procedure is performed either at a single or multiple temperatures. Effective technique for sheet extrusion or multilayer film, barrier bubble wrap. The measurement is indirectly related to the amount of antioxidant.