A new PvT device for high performance thermoplastics: Heat transfer analysis and crystallization kinetics identification

作者：Pignon Baptiste; Tardif Xavier; Lefevre Nicolas; Sobotka Vincent^*; Boyard Nicolas; Delaunay Didier

来源：Polymer Testing, 2015, 45: 152-160.

DOI：10.1016/j.polymertesting.2015.05.013

• Heat transfer
• Crystallization kinetics
• Specific volume
• PvT diagram

The quality of thermoplastic parts strongly depends on their thermal history during processing. Heat transfer modelling requires accurate knowledge of thermophysical properties and crystallization kinetics in conditions representative of the forming process. In this work, we present a new PvT apparatus and associated method to identify the crystallization kinetics under pressure. The PvT-xT mould was designed for high performance thermoplastics: high temperature (up to 400 degrees C), high cooling rate (up to 200 K/min) and very high pressure (up to 200 MPa). Specific volume measurements were performed at a low cooling rate to avoid a thermal gradient. The crystallization kinetics under pressure can be identified for a wide range of cooling rates by an inverse method taking into account the thermal and crystallinity gradients. Since identification is based on volume variations, the proposed methodology is non-intrusive. Furthermore, the enthalpy released by the crystallization was measured during the experiment by a heat flux sensor located in the moulding cavity.

• 出版日期2015-8