Thermal Analysis

Thermogravimetric Analysis (TGA)

Thermogravimetric Analysis (TGA) measures changes in weight of a sample with increasing temperature. Measurements are used primarily to determine the composition of materials and to predict their thermal and oxidative stability. Also the technique is used to estimate the lifetime of a product, decomposition kinetics, moisture/volatile content, melting point, glass transition, heat capacity, crystallinity and purity.

When coupled to mass spectrometer (MS), the gaseous species that are released as a result of thermal decomposition or gas sorption reactions are transferred to MS through heated capillary transfer line.  The quadrupole detector in MS provides qualitative chemical determination (mass/charge from 1 to 300) of evolved gases giving information about reactions in real time.

Discovery Series TGA Q5500 coupled with Discovery MS (TA instruments) has the following features:

  • Temperature range from room temperature up to 1200°C in many different environments
  • Purge gasses available are N2, He, Ar, air; reactive gasses can be manually introduced from the secondary gas port
  • The Gas Delivery Module allows gas switching and blending of up to four different purge gases 
  • The IR furnace is capable of heating rates of 0.1 to 500°C/min. in linear control, or over 2,000°C/min. in ballistic heating. Typical heating rates are 5-20°C per minute
  • Multiple samples can be analyzed by 25 position autosampler
  • The following pans are available: 100 µl high temperature platinum pans and 250 µl ceramic pans, and 80 µl sealed aluminum pans
  • Optimal sample size 10-50 mg
  • Air sensitive samples can be analyzed by using sealed aluminum pans that the autosampler will 'punch' open before loading into the furnace. 
  • The resolution of the technique is affected by the heating rate, sample size and purge gas composition.

Differential Scanning Calorimetry (DSC)

Description

DSC measures temperatures and heat flows associated with thermal transitions in a material. Properties measured include glass transitions, “cold” crystallization, phase changes, melting, crystallization, product stability, cure/cure kinetics, and oxidative stability.

Applications

Pharmaceuticals, Ceramics, Inorganics, Fuels, Polymers, Glass, Adhesives, paints, Resins, Lubricants, Catalysts

Equipment

Q2000 MDSC® (Modulated Differential Scanning Calorimeter)

Temperature Range: Ambient to 725°C
With Cooling Accessories: -90 to 550°C
Temperature Accuracy: +/- 0.1°C
Temperature Precision: +/- 0.01°C
Calorimetric Reproducibility (indium metal): +/- 0.05%
Calorimetric Precision (indium metal): +/- 0.05%
Dynamic Measurement Range: >+/- 500 mW
Baseline Curvature: (Tzero; -50 to 300 ̊C) 10 μW
Baseline Reproducibility with Tzero: +/- 10 μW
Sensitivity: 0.2 μW

Simultaneous Differential Scanning Calorimetry/Thermo Gravimetric Analyzer (SDT)

Description

Provides a true simultaneous measurement of heat flow (DSC) and weight change (TGA) on the same sample from ambient to 1,500oC. DSC noise is <4 microwatts and the TGA balance sensitivity is 0.1 microgram. A heat flux DSC design with separate sample and reference pans is used, and is calibrated for heat flow measurements using sapphire. This system features automated furnace movement and a horizontal purge gas system with digital mass flow controllers and programmable gas switching capability. A separate tube permits introduction of reactive gases into the sample chamber.

Applications

Pharmaceuticals, Ceramics, Inorganics, Fuels, Polymers, Glass, Adhesives, paints, Resins, Lubricants, Catalysts

Equipment

Q600 SDT

Sample Capacity: 200 mg (350 mg including sample holder)
Balance Sensitivity: 0.1 μg
Temperature Range: Ambient to 1500°C
Heating Rate Ambient to 1000°C: 0.1 to 100°C/min
Heating Rate Ambient to 1500°C: 0.1 to 25°C/min
DTA Sensitivity: 0.001°C
Calorimetric Accuracy/Precision: ± 2% (based on metal standards)
Sample Pans: Platinum: 40 μL, 110 μL and Alumina: 40 μL, 90 μL