Kinetics of Thermal Degradation of Non-Woven Plastics: Model-Free Kinetic Approach

The thermo-degradative behaviour of non-woven plastics was studied in order to analyze their thermal stability and subsequent recycling method. Non-isothermal thermogravimetric experiments using wide range of heating rates of 10, 20, 40, 60, 80,100 degrees Cmin(-1) have been performed from ambient to 900 degrees C in a thermo-balance with the objective of determining the kinetic parameters. Four model free kinetic approaches such as Friedman method, Coats-Redfern (modified) method, Flynn-Wall-Ozawa (FWO) method and Kissinger method have been used to determine kinetic parameters for the two stage degradation of the non-woven plastic sample including the thermal degradation of synthetic plastics in the first step followed by the subsequent degradation of inorganic fillers in the second step. The activation energy obtained for first stage degradation is found significantly lower (106-112 kJ/mol) compared to the second stage degradation (191-202 kJ/mol). This result would help design a process for the valorisation of synthetic polymer and segregation of the filler materials in the plastic sample to be reused further.