Melt Crystallization Behavior of Injection-Molded High-Density Polyethylene Based Upon a Solidification Kinetic Analysis

Abstract

Rheological characterization and an in-situ temperature measurement were carried out to investigate the solidification behavior and crystallization kinetics of injection-molded (IM) high-density polyethylene (HDPE) samples. The temperature profiles obtained via the enthalpy transformation method (ETM) were also used to disclose the effect of cooling rate on the solidification kinetics during the IM process. A four parameter model (FPM) was developed in the present work, based on a three-parameter model (TPM) we proposed previously, with the FPM shown to have an obviously better fitting effect. It was seen that heat transfer at locations χ ≤ 0.5 was primarily dominated by a thermal conduction mechanism, which was unlike the situation when χ > 0.5, with χ being the fractional distance from the mold surface to the center. The results of the present study are suggested to be of significance to further research on the correlation between microstructures and properties of IM products.

Keywords:

• Cooling curves
• injection molding
• melt crystallization
• polyethylene
• solidification kinetics

Acknowledgments

The authors are gratefully indebted to the National Natural Science Foundation of China (Nos. 51203002, 51273001), the “211 Project” of Anhui University. In addition, the financial support from Institute of High Performance Rubber Materials & Products (Hefei) and the Collaborative Innovation Center for Petrochemical New Materials (Anqing) are acknowledged.

Additional information

Funding

The National Natural Science Foundation of China (51203002, 51273001). The Doctoral Program of Higher Education of China (No. 20113401110003). The “211 Project” (ZLTS2015059, 201510357142, J01005113 and J18515262) of Anhui University.