POLYMERS
Polymer Analysis in Detail
The No. 1 thermo-analytical method for polymers is DSC (Differential Scanning Calorimetry), with which thermal effects and derived parameters such as melting, CrystallizationCrystallization is the physical process of hardening during the formation and growth of crystals. During this process, heat of crystallization is released.crystallization, crosslinking, 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, Specific Heat Capacity (cp)Heat capacity is a material-specific physical quantity, determined by the amount of heat supplied to specimen, divided by the resulting temperature increase. The specific heat capacity is related to a unit mass of the specimen.specific heat capacity and OxidationOxidation can describe different processes in the context of thermal analysis.oxidation can be investigated.
TGA (Thermogravimetry) provides information about the composition and thermostability of polymers, polymer mixtures and blends. In addition, gas analyses can be performed via coupling with QMS (Quadrupole Mass Spectrometry) or FT-IR (Fourier Transform Infrared Spectroscopy).
Dilatometry and TMA (Thermomechanical Analysis) yield information on expansion or shrinkage behavior as well as on the coefficient of thermal expansion. DMA (Dynamic Mechanical Analysis) also provides values for the coefficient of elasticity and information regarding visco-elastic behavior, aging, CreepCreep describes a time and temperature dependent plastic deformation under a constant force. When a constant force is applied to a rubber compound, the initial deformation obtained due to the application of the force is not fixed. The deformation will increase with time.creep and RelaxationWhen a constant strain is applied to a rubber compound, the force necessary to maintain that strain is not constant but decreases with time; this behavior is known as stress relaxation. The process responsible for stress relaxation can be physical or chemical, and under normal conditions, both will occur at the same time. relaxation.
With DEA (Dielectric Analysis), the 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 behavior of reactive resin systems can be measured, even during processing.
LFA (Laser/Light Flash Analysis) measures the Thermal DiffusivityThermal diffusivity (a with the unit mm2/s) is a material-specific property for characterizing unsteady heat conduction. This value describes how quickly a material reacts to a change in temperature.thermal diffusivity (even for thermoplastic melts); using that information, the Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity can then be calculated. A tried and tested method for determining the Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity of polymer isolation foams is the measurement of heat flow by means of HFM.
DSC | Pressure- DSC | Photo- DSC | TGA/ STA | DIL | TMA | DMA | DEA | LFA | HFM/ GHP | |
Thermoplastics | • | o | - | • | • | • | • | - | • | - |
Thermoplastic Elastomers | • | o | - | • | • | • | • | - | • | - |
Elastomers/Rubbers | • | o | - | • | • | • | • | o | • | o |
Thermosets | • | • | • | • | • | • | • | • | • | o |
Paints/Coatings | • | o | • | • | - | • | • | • | o | - |
Adhesives | • | - | • | • | o | • | • | • | o | - |
Foams | • | - | - | • | • | • | • | o | - | • |
Composites | • | - | - | • | • | • | • | • | • | - |
legend:
• ideal
o possible with some effort
- not possible, not practical