Material characterisation

Calorimetric analyses of polymers are usually carried out using differential scanning calorimetry (DSC). DSC is used to determine the amount of heat absorbed or released by a sample while it is subjected to a defined heating and cooling programme. In this way, thermodynamic parameters such as transformation temperatures as well as melting and reaction heat quantities can be determined. The following aspects can be analysed with the DSC:

• Physical transformations: Melting, crystallisation, evaporation, glass transitions
• Chemical processes: Decomposition and pyrolysis behaviour, oxidation stability (OIT), composition, reaction enthalpy, reaction kinetics, cross-linking, curing

Laboratory equipment

• DSC module Q1000 (TA Instruments)
• DSC 25 (TA Instrumenmts)
• Measurements in the range -90 °C - 600 °C possible

Thermogravimetric analysis (TGA) is used to analyse physical processes and chemical reactions associated with mass changes in a specific gas atmosphere (e.g. N2 or synt. air). This allows weight loss or gain to be recorded as a function of temperature or time. The application examples are: Determination of polymer compositions, carbon black content, Quantitative determination of fillers e.g. chalk, talc, glass fibre, stabiliser Degradation / ageing of plastics, ...

Laboratory equipment

• TGA Q500 (TA Instruments)
• Measurements in the RT - 1000 °C range possible

Dynamic mechanical analysis (DMA) provides information on the development of mechanical properties under low, usually sinusoidal dynamic load as a function of temperature, time and/or frequency. The measuring principle of DMA consists of loading a sample with a sinusoidal load (frequency) and measuring the resulting stress. Examples of applications for DMA are Viscoelastic behaviour of a polymer, glass transition, crystallisation and melting, relaxation behaviour, phase transitions, storage and loss modulus, relaxation and creep behaviour, curing and polymerisation reactions, material defects, effects due to filling materials, ...

Laboratory equipment

• TMA Q800 (TA Instruments)
• Measurements possible in the temperature range -150 °C - 600 °C and frequency range from 0.01 to 200 Hz

Thermodynamic analysis (TMA) is used to measure dimensional changes in a sample under mechanical stress as a function of temperature.

TMA allows the determination of thermal effects (softening e.g. Tg of polymers, change in expansion coefficient, swelling in solvents, shrinkage), temperatures that characterise the thermal effect, deformation step heights (extent of deformation) and the thermal expansion coefficient.

Laboratory equipment

• TMA Q400 (TA Instruments)
• Measurements possible in the RT - 1000 °C range