Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (12): 2505-2512.doi: 10.3866/PKU.WHXB201310213

• THERMODYNAMICS, KINETICS, AND STRUCTURAL CHEMISTRY • Previous Articles     Next Articles

Thermal Stability and Dynamic Thermal Mechanical Properties of Microcellular Polylactic Acid Scaffolds

WANG Fang1, SHENG Shen-Jun1,2, GUO Ge-Pu3, MA Qing-Yu4   

  1. 1 Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023, P. R. China;
    2 School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, P. R. China;
    3 Physics School, Nanjing University, Nanjing 210093, P. R. China;
    4 Key Laboratory of Optoelectronics of Jiangsu Province, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
  • Received:2013-08-14 Revised:2013-10-21 Published:2013-11-28
  • Contact: MA Qing-Yu E-mail:maqingyu@njnu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (11274176), Natural Science Foundation of Jiangsu Provincial Department of Education, China (09KJD350001), and Opened-Laboratory Foundation of Nanjing, China (1640703064).

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Abstract:

Solvent-free solid-state foaming technology was used to fabricate microcellular polylactic acid (PLA) scaffold materials with cell sizes from 350 to 20 μm at saturation pressures of 2.5, 3.5, 4.0, and 5.0 MPa in carbon dioxide. The corresponding thermodynamic parameters were measured, including the decomposition temperature and rate, storage/loss modulus, and loss factor, using thermogravimetric analysis, dynamic thermal mechanical analysis, and scanning electron microscopy. The Kissinger, Ozawa-Doyle, and Vyazovkin equations were used to calculate the thermal decomposition kinetics for PLA foams of different cell sizes; their lifetimes in nitrogen were also obtained. It was observed that PLA foams with larger cell sizes, lower average activation energies, and better flexibilities could be fabricated at lower saturation pressures, resulting in reduced decomposition times.

Key words: Polylactic acid scaffold, Solid state foaming, Thermogravimetric analysis, Dynamic thermal mechanical analysis, Thermal decomposition kinetics