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Modulated and pressure DSC services

Pressure DSC (PDSC), which measures heat flow at increased pressure, is useful for studying decomposition and oxidative stability. Analysis under oxygen can be done on heating to observe oxidation onset temperatures or isothermally to observe oxidation induction times.

We can accommodate pressures up to 1000 psi under nitrogen or oxygen, with operation from ambient temperature to 500 °C. Other gases, such as carbon dioxide, can be used if necessary. Transitions obscured by vaporization may be observed since under pressure boiling points may be elevated above their decomposition temperatures.

Some typical applications of PDSC include:

  • Oxidative stability of polymers and additives
  • Antioxidant screening
  • Characterization of thermal stability
  • Plasticization effects of gasses
  • Phase transitions at elevated pressures
  • Determination of reactions or transitions obscured by evaporation

Modulated DSC (MDSC) allows the separation of complex overlapping thermal events that may occur in the heat flow. This is accomplished by imposing a temperature sine wave on an underlying linear or isothermal temperature program to separate the response that is rate dependent from the total conventional heat flow response. The total heat flow is thus separated into a reversing component that includes events that are related to the heat capacity and a nonreversing component dependent on kinetic events.

Some typical applications of MDSC include:

  • Determination of phase transitions obscured by nonreversing phenomena
  • Monitoring of cure processes
  • Characterization of polymer aging

DSC analyses measure the heat flow and therefore cannot provide atomic level structural detail for identification of the material.  However, distinctive transitions can be used for fingerprint characterization.

 

Our scientists have more than 25 years of experience with thermal analysis techniques and have extensive expertise with a wide variety of polymers and plastics, as well as additives such as antioxidants, plasticizers and fillers.

Pressure DSC curves collected under an oxygen atmosphere

Pressure DSC curves collected under an oxygen atmosphere showing differences between the oxidative induction times of two materials.

Modulated DSC traces of a material with an obscured glass transition due to thermal history effects

Modulated DSC traces of a material with an obscured glass transition due to thermal history effects.  MDSC allows for the measurement of the glass transition in the reversing heat flow by separating it from nonreversing heat flow effects.

Arkema Analytical Services DSC specialty test services include:

  • Modulated and pressure DSC data analysis
  • Measurement of oxidative onset temperature (OOT), oxidative induction time (OIT) and material decomposition
  • Determination of phase transitions
  • Thermal fingerprinting
  • Thermoset cure monitoring
  • Material purity determination
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