A Study of the Crystallization, Melting, and Foaming Behaviors of Polylactic Acid in Compressed CO2

International Journal of Molecular Sciences

Wentao Zhai¹  Yoorim Ko¹  Wenli Zhu¹  Anson Wong¹ 

[1] Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, M5S 3G8, Canada;

关键词: crystallization;    polylactic acid;    compressed CO₂;   

DOI  :  10.3390/ijms10125381

来源: mdpi

【 摘 要 】

The crystallization and melting behaviors of linear polylactic acid (PLA) treated by compressed CO₂ was investigated. The isothermal crystallization test indicated that while PLA exhibited very low crystallization kinetics under atmospheric pressure, CO₂ exposure significantly increased PLA’s crystallization rate; a high crystallinity of 16.5% was achieved after CO₂ treatment for only 1 min at 100 °C and 6.89 MPa. One melting peak could be found in the DSC curve, and this exhibited a slight dependency on treatment times, temperatures, and pressures. PLA samples tended to foam during the gas release process, and a foaming window as a function of time and temperature was established. Based on the foaming window, crystallinity, and cell morphology, it was found that foaming clearly reduced the needed time for PLA’s crystallization equilibrium.

【 授权许可】

CC BY   
© 2009 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.