Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (2): 344-355.doi: 10.3866/PKU.WHXB201611023

• ARTICLE • Previous Articles     Next Articles

Structure and Kinetics of Thermal Decomposition Mechanism of Novel Silk Fibroin Films

Hai-Yang YU1,2,Fang WANG1,*(),Qi-Chun LIU1,2,Qing-Yu MA3,Zheng-Gui GU2,*()   

  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 Jiangsu, Nanjing 210023, P. R. China
    3 School of Physics and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
  • Received:2016-10-10 Published:2017-01-12
  • Contact: Fang WANG,Zheng-Gui GU E-mail:wangfang@njnu.edu.cn;07160@njnu.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(11474166);College of Natural Science Foundation of Jiangsu Province, China(15kJB150018)

Abstract:

A new CaCl2-formic acid dissolution method was used to prepare silk fibroin (SF) films. Films SF-1.5 and SF-3.0 were prepared using 1.50% (w, mass fraction) and 3.00% (w) CaCl2-formic acid solutions, respectively. The molecular conformations and crystal structures of the films were characterized by Fourier transform infrared spectroscopy and X-ray diffraction. The thermal stability, thermal decomposition properties, and effect of CaCl2 concentration on the thermodynamic parameters, kinetic parameters, and formation mechanism of the SF films were investigated using thermogravimetry techniques and the models of Kissinger, Ozawa, and Vyazovkin. The results showed that the SF-1.5 film mainly contained β-sheet structure, while the main molecular conformation in the SF-3.0 film was random coils. The decomposition temperature, activation energy, and activation enthalpy of SF-3.0 were lower than those of SF-1.5, while the thermal stability of SF-1.5 was higher than that of SF-3.0. In addition, the thermal decomposition of the SF films was studied by the Achar and Coats-Redfern methods. The mechanism of decomposition of these SF films followed the two-dimensional diffusion (cylindrical symmetry) law in the temperature range of 190.00-330.00℃.

Key words: Silk fibroin, Thermal decomposition mechanism, Thermodynamics, Thermogravimetry, Fourier transform infrared spectroscopy

MSC2000: 

  • O642