Thermal Analysis and Thermal Decomposition Kinetics of Artemisia vulgaris L.
The thermal decomposition behavior and non-isothermal kinetics of Artemisia vulgaris L.in nitrogen were studied by thermogravimetric-differential thermogravimetric(TG-DTG)technique.The results showed that its thermal decomposition was divided into two-step process.In the first stage,the weight loss rate was 3.75％,which was mainly the weight loss of water and a small amount of volatile oil in A.vulgaris L..In the second stage,the weight loss rate was 71.12％,which was mainly the thermal decomposition of volatile oils and lignocellulose.Meanwhile,the kinetic parameters of A.vulgaris L.were obtained using the Achar differential equation and Coats-Redfern integral equation of the single scanning method,and its control mechanism function of the thermal decomposition was determined.The kinetic parameters were verified by Kissinger equation,Flynn-Wall-Ozawa equation and Starink equation of the multiple scanning rate method.It was found that the thermal decomposition process belonged to the F3(third-order reaction)mechanism control,and the mechanism function f(α)=0.5(1-α)3,g(α)=(1-α)-2-1.The apparent activation energy and the pre-exponential factor were 124.76 kJ/mol and 5.78×1010 s-1,respectively.The thermal decomposition non-isothermal kinetic equation of A.vulgaris L.was dα/dt=(5.78 × 1010/β)×(0.5 ×(1-α)3)× exp(-15 006/T).According to the estimation of thermal decomposition kinetic parameters,the shelf-life of A.vulgaris L.was 4-5 years at room temperature.
万方数据
维普
