methods

Thermomechanical Analysis (TMA) 

For measuring both the thermal and the mechanical properties, a thermomechanical analyzer (TMA) is used. Temperature-dependent dimensional changes in solids, liquids and pastes determine the suitability of an application for a given material or provide information about the composition, structure and conditions of processing.

TMA measures these dimensional changes while allowing the sample to be subjected to an additional mechanical load (DIN 51005, ASTM E 831, ASTM D 696, and ASTM D 3386). This makes it possible to determine the thermal length change (with negligible mechanical load: dilatometry, DIN 51045) as well as the thermomechanical characteristics.

Besides the linear thermal expansion and the coefficient of thermal expansion, TMA can also be used to study Phase TransitionsThe term phase transition (or phase change) is most commonly used to describe transitions between the solid, liquid and gaseous states.phase transition temperatures, SinteringSintering is a production process for forming a mechanically strong body out of a ceramic or metallic powder. sintering temperatures, shrinkage steps, Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition temperatures, dilatometric softening points, Volumetric ExpansionThe volume of a gas, solid or liquid changes if the temperature, the pressure or the forces acting on that gas/solid/liquid change. In the case of thermal analysis, we are looking at temperature-dependent changes.volumetric expansion, DensityThe mass density is defined as the ratio between mass and volume. density changes, delamination and SinteringSintering is a production process for forming a mechanically strong body out of a ceramic or metallic powder. sintering kinetics.

Instruments for thermomechanical analysis are applied in all areas from research and development to quality control. Typical domains include plastics and elastomers, thermosets, composite materials, adhesives, films and fibers, ceramics, glass and metals.

Measurement on an epoxy resin with a sample length of 6 mm in expansion mode (fused silica sample holder); 1st and 2nd heating runs at a rate of 2 K/min.

Thermal Expansion

The linear thermal expansion is an important variable for assessing the dimensional behavior of a material in response to a change in temperature.

This plot shows the thermal expansion (dL/L0 in %) of an epoxy resin between -70°C and 270°C. In the first heating (blue curve), the onset of the Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition (Tg) occurs at 123°C. In the second heating (red curve), the onset of Tg is slightly shifted, to 125°C. This shift could be due to RelaxationRelaxation은 고무에 일정한 변형률이 가해지면, 변형률을 유지하기 위해 필요한 힘은 일정하지는 않지만 시간에 따라 감소합니다. 이러한 특성을 ‘응력 완화’라고 부릅니다. 응력완화의 원인이 되는 과정은 물리적 또는 화학적 그리고 정상적인 조건 하에, 둘 다 동시에 일어날 수 있습니다. relaxation effects or post-Curing (Crosslinking Reactions)Literally translated, the term “crosslinking“ means “cross networking”. In the chemical context, it is used for reactions in which molecules are linked together by introducing covalent bonds and forming three-dimensional networks.curing.