Morphological Study of Linear Low-Density Polyethylene Molded by Gas-Assisted Injection Molding

Abstract

Position dependence for the supermolecular morphology of linear low density polyethylene (LLDPE) prepared by gas-assisted injection molding (GAIM) was examined using scanning electron microscopy (SEM). Combined morphological feature of both spherulites and those with ring-bands was observed, which differs from our previous studies on the HDPE counterparts. Dynamic rheological measurements were also carried out to interpret the formation mechanism of the morphological feature. The difference in hierarchical crystalline structures between LLDPE and HDPE can be due to their different chain branches as well as the resultant different response to the local shear fields during the GAIM process.

Keywords:

• Crystalline morphology
• Gas-assisted injection molding
• Linear low-density polyethylene

ACKNOWLEDGMENT

This work is financially supported by the National Natural Science Foundation of China (50673067), the Major State Basic Research Projects (2005CB623808). Mr. Zhu Li (Testing and analytical Center of Sichuan University) and Dr. Chao-Liang Zhang (Huaxi College of Stomatology) are greatly appreciated by the authors.