Pharmaceutical and polymer industries are increasingly interested in both TGA and DSC. Drug companies use these techniques to test for drug stability and crystalline state (or lack thereof). For example, some medicines work better in a particular crystalline polymorph, and others are more effective in an amorphous state. Polymer companies are interested in measuring numerous properties associated with heat, such as mechanical dimensions and stability, chemical stability, and physical states (e.g., glass transition) related to mechanical performance.
Thermal analysis is not only about high temperatures. Some instruments have a cooling function that enables monitoring of low-temperature events such as glass transition in polymers.
Type of materials respondents work with that require them to perform thermal analysis:
| Polymers | 33% |
| Pharmaceutical materials | 18% |
| Metals | 13% |
| Foods | 10% |
| Chemicals | 8% |
| Environmental materials | 5% |
| Ceramics | 3% |
| Other | 10% |
Any property that alters with temperature change can be associated with some form of thermal analysis. This technique, also called calorimetry, correlates temperature-dependent events to physical characteristics of a sample including: physicochemical structure, reduction, oxidation, evolved gases, decomposition, elongation, brittleness, strength, structure, and mass. Every industry concerned with the relationship between energy and how their products behave in the real world uses thermal analyzers. Thermal measurements provide food companies with values for caloric (energy) content, materials manufacturers with phase transition temperatures, and academic researchers with insights into phases of matter. Every phase of a product’s life cycle, from development to manufacturing, quality control and release involves thermal measurements.
Thermal analysis works best when investigators know what they’re looking for, or at least know the identity of the sample. To reduce that uncertainty, some thermal analyzers incorporate a spectrophotometer in the mix. These techniques, known collectively as thermo-optical analysis, include thermospectrometry, thermorefractometry, thermoluminescence, and thermomicroscopy. All work on the principle that a sample’s interaction with light changes with temperature. Numerous discrete and continuous thermally relevant events can be measured this way, including crystallization, melting, corrosion, phase transitions, drying, and polymorphism.
Vendors offer a very broad range of analyzers. Differential Scanning Calorimetry (DSC) is by far the number-one seller, with Thermogravimetric Analysis (TGA) coming in second. The two methods, moreover, are complementary, measuring fine or subtle properties and gross properties, respectively.
Type(s) of thermal analysis respondents are currently using or planning to purchase for their lab.
| Differential Scanning Calorimetry | 24% |
| Thermogravimetric Analysis | 23% |
| Differential Thermal Analysis | 13% |
| Dynamic Mechanical Analysis | 8% |
| Thermomechanical Analysis | 7% |
| Evolved Gas Analysis | 6% |
| Dilatometry | 4% |
| Thermo-optical Analysis | 4% |
| Dielectric Thermal Analysis | 3% |
| Other | 8% |
Vendors also offer Simultaneous Thermal Analyzers (STA) that combine TGA and DSC in a single instrument, a high-pressure DSC, and an instrument that allows users to swap out TGA and DSC cells.
Fifty-one percent of the respondents are currently performing or planning to perform Simultaneous Thermal Analysis (STA) in their labs.
| Currently performing STA | 16% |
| Not currently performing STA, but would like to use this method | 35% |
| No, this method does not work for our analysis | 49% |
The top ten features / factors that influence our respondents in buying a thermal analyzer include:
| Performance / Heat flow measurements (resolution, sensitivity, precision and accuracy) | 100% |
| Wide temperature range | 92% |
| Versatility – able to measure large and small sample material | 86% |
| Safety of operators | 81% |
| Availability of accessories and replacement parts | 79% |
| Low operating/ownership cost | 72% |
| Low maintenance/easy to clean | 68% |
| Ease of use (calibration and adjustments) | 67% |
| Service and support | 63% |
| Warranty | 50% |
