Thermal Analysis

THERMAL ANALYSIS

Thermal Analysis Benefits:


Differential scanning calorimetry (DSC):

General Information

The differential scanning calorimetry (DSC) testing was performed using a TA Instruments Q2000 model DSC (2012-2022) and a Perkin Elmer DSC7 (2008-2012).  The material sample specimen used for analysis measured approximately 10-20mg.  These methods are based on ASTM D 3418 and ISO 11357.

Four Step Method for Semi-Crystalline Polymer Analysis - DSC4 

The DSC testing for a semi-crystalline thermoplastic material generally involves four thermal curves.  The first step (#1) is a heating thermal ramp that removes the thermal history from the polymer.  The second step (#2) is a slow-cooling thermal ramp allowing sufficient crystallization of the crystallites in the polymer.  The third step (#3) is a second heating thermal ramp which shows the melting transitions from an equal basis for all analyzed specimens.  The fourth step (#4) is a very slow cooling thermal ramp that provides unique information about the crystallization behavior for the polymer macromolecules. 

A typical DSC analysis of a semi-crystalline thermoplastic specimen using four steps could use the following example parameters: step #1 - first heating step from 50°C-300°C at +10°C per minute, step #2 – first cooling step from 300°C-50°C at -10°C per minute, step #3 - second heating step from 50°C-300°C at +10°C per minute and step #4 – second cooling step from 300°C-50°C at -2.5°C per minute.  The maximum and minimum temperature limits can be modified depending on the specific requirements intrinsic to the material.  

Three Step Method for Amorphous Polymer Analysis - DSCQ

The DSC analysis for amorphous polymers generally involves three steps. The first step (#1) is a heating thermal ramp that removes the thermal history from the polymer.  The second step (#2) is a fast-cooling thermal ramp meant to quench the polymer material and improve the detection of the material's glass transitions.  The third step (#3) is a second heating thermal ramp which shows the transitions from an equal basis for all analyzed specimens.  This procedure can also be applied to semi-crystalline polymers to improve the detection of their material glass transitions by inhibiting the crystallization of the material.

A typical DSC analysis of a thermoplastic specimen using three steps could use the following example parameters: step #1 - first heating step from -65°C to 205°C at +20°C per minute, step #2 – quench cooling step from 205°C to -65°C at approximately -100°C per minute, step #3 - second heating step from -65°C to 205°C at +20°C per minute.    The testing will provide a calculated glass transition (Tg) and additional thermal information for additives.  The maximum and minimum temperature limits can be modified depending on the specific requirements intrinsic to the material.  

Three Step Method for Checking Curing in Thermoset Polymer Analysis -DSCC

The DSC analysis for thermoset materials for detecting thermal transitions typically involves three steps.

Step #1 - first heating step from 50°C-200°C at +5°C per minute, step #2 – cooling step from 200°C-50°C at -5°C per minute, and step #3 - second heating step from 50°C-200°C at +5°C per minute.  The first step (#1) is a heating thermal ramp that removes the thermal history from the polymer.  This step may also show exothermic transitions which may be related to remaining cure-based chemical reactions.  The second step (#2) is a slow-cooling thermal ramp to return to initial temperatures.  The third step (#3) is a second heating thermal ramp which shows the thermal state of the thermoset after the first heat ramp.  

DSC References

 ASTM Standard D3418, 2008, "Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry," ASTM International, West Conshohocken, PA, 2008, DOI: 10.1520/D3418-08, www.astm.org.

International Organization for Standardization. (2016). "Plastics -- Differential Scanning Calorimetry" (ISO/DIS Standard No. 11357).


Thermogravimetric Analysis (TGA):

 The thermogravimetric analysis (TGA) testing was performed using a  TA Instruments Q500 model TGA (2012-2022) and a Perkin Elmer TGA7 (2008-2012).  In TGA, an approximately 10 mg specimen portion is used for analysis.

All Purpose Method for All Polymer Types Analysis - TGA

The mass is measured while the temperature of the sample portion is raised from 50°C to 850°C at a rate of 10°C per minute.  The temperature scan provides information on the degradation of the material sample dependent on temperature.  During the TGA, the purge gas was switched from nitrogen to air at 800°C causing oxidative degradation of the sample.  Thermal analysis by TGA on a sample specimen provides a unique curve based on a complicated thermal degradation pathway. This method is based on ASTM E 1131.

Incremental Specialty Method for All Polymer Types Analysis - TGASI

The mass is measured while the temperature is controlled by a maximum limit of mass loss (weight %) per minute.  The temperature scan provides information on the material degradation dependent on the rate of degradation and helps to resolve different temperature dependent degradation processes.  

TGA References

 ASTM Standard E1131, 2008 (2014), "Standard Test Method for Compositional Analysis by Thermogravimetry," ASTM International, West Conshohocken, PA, 2014, DOI: 10.1520/E1131-08R14, www.astm.org 

International Organization for Standardization. (2021). "Plastics -- Thermogravimetry (TG) of Polymers" (ISO/DIS Standard No. 11358).

Dynamic Hybrid Rheometry (DHR):

 The dynamic hybrid rheometry (DHR) testing was performed using a TA Instruments DHR2 (2012-2022).  DHR is a companion technique to Dynamic Mechanical Analysis (DMA) using torsion.

Melt Flow Index (MFI):

Melt flow Index rheological testing was performed using a Dynisco Series 4004 Kayeness Polymer Tester according to ASTM D1238 (or ISO 1133).  The melt flow testing temperature and weight will be dependent on the material to be tested.  Typical parameters can use 300°C and a 1.2 kg weight.

MFI References

 ASTM Standard D1238, 2010, "Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion," ASTM International, West Conshohocken, PA, 2010, DOI: 10.1520/D1238-10, www.astm.org. 

International Organization for Standardization. (2021&2011). "Plastics — Determination of the melt mass-flow rate (MFR) and melt volume-flow rate (MVR) of thermoplastics" (ISO/DIS Standard No. 1133).