The difference and relationship between glass transition temperature and heat distortion temperature
Thread Content
Thermal deformation temperature is the temperature at which a certain deformation occurs under the action of a certain constant force. The glass transition temperature is the temperature at which the glassy state changes to a highly elastic state. What is the difference and connection between the two? This post was last edited by wivern on 2009-4-18 08:36 ]
The heat distortion temperature is lower than the glass transition temperature. The difference is that according to the definition, one is the temperature at which deformation occurs, and the other is the transition temperature from the glassy state to the highly elastic state. This post was last edited by wivern on 2009-4-18 08:34 ]
The glass transition temperature corresponds to the temperature at which macromolecular chain segments begin to move. The glass transition temperature is the transition temperature at which a polymer chain segment changes from being immobile to being able to move. Strictly speaking, this transition is a region, called the glass transition region. Its research object is microscopic chain segments, and the research is conducted based on the polymer chain structure. Thermal deformation temperature refers to polymer materials, which is the temperature at which polymer materials begin to undergo thermal deformation. The research object of thermal deformation temperature is the performance of macroscopic polymer aggregate structure. It refers to the temperature corresponding to a certain deformation of a test specimen made according to a specified size under load and heating rate. The glass transition temperature has little to do with the resin content ； However, if the interface force formed between the resin and reinforcement in the composite material is too weak or too strong, it will affect the data of the glass transition temperature test.
For high molecular weight polymers, the glass transition temperature is the temperature at which the polymer material transitions from a glassy state to a highly elastic state.: For low molecular weight polymers, the glass transition temperature is the temperature at which the polymer transitions from the glassy state to the viscous flow state. Thermal deformation temperature refers to the temperature at which a specified load (1.81N/mm2 or 0.45 N/mm2) is applied to a rectangular resin sample of a certain size immersed in a thermally conductive liquid medium that is heated at a heating rate of 120°C/h, and the deformation amount at the midpoint of the sample reaches a specified value corresponding to the height of the sample. It can be seen from the above definition: Glass transition temperature/heat distortion temperature is a temperature value ； The glass transition temperature is the temperature corresponding to the complete transformation of the phase state, and the heat distortion temperature is the temperature corresponding to the phase transformation to a certain extent.
Read the book Polymer Physics and you will understand everything.
"Polymer Physics" explains that the glass transition temperature is the transition temperature at which a polymer chain segment changes from being immobile to being able to move. Strictly speaking, this transition is a region, called the glass transition region. Its research object is microscopic chain segments, and the research is conducted based on the polymer chain structure. Thermal deformation temperature refers to polymer materials, which is the temperature at which polymer materials begin to undergo thermal deformation. Glass transition temperature/heat distortion temperature is a temperature value ； The glass transition temperature is the temperature corresponding to the complete transformation of the phase state, and the heat distortion temperature is the temperature corresponding to the phase transformation to a certain extent.