Study On The Thermal Degradation Kinetics Of PET Depolymerization Intermediates

As is well known,microwave irradiation has thermal effects and non-thermal effects,but there is no unified and clear understanding about non-thermal effects so far.The information of energy change caused by the non-thermal effect of microwave can be obtained by researching on the thermal degradation kinetics of the intermediates by PET hydrolysis.And the mechanism of the non-thermal effect of microwave can be clarified.Besides,the theoretical basis and method for the effective use of microwave can also be provided.Based on the previous research work of the group,in this thesis,PET hydrolysis was regarded as the “model reaction”,the intermediate products by PET conventional and microwave hydrolysis at 170??180?and 190? were obtained by synchronous contrast experiment.And the information of material change caused by the non-thermal effect of microwave was also obtained by the qualitative and quantitative analysis of intermediate products.The thermal degradation kinetics of the intermediate products was analyzed by Satava method.Based on this analysis,the information of energy change caused by the non-thermal effect of microwave was obtained.On the basis of the results of infrared(IR)and scanning electron microscope(SEM),gel permeation chromatography(GPC)and potentiometric titration analysis.The results indicated that PET microwave hydrolysis was a process which was mainly dominated by random depolymerization at the initial reaction stage,and then random and regular depolymerization simultaneously,finally,the regular depolymerization was dominated at the end of reaction,however,the conventional hydrolysis of PET was a process dominated by regular depolymerization.Moreover,the random depolymerization was caused by the non-thermal effect of microwave.PET conventional hydrolysis was a kinetics continuous process,which can be expressed by a kinetic equation.On the contrary,the microwave hydrolysis of PET was not a dynamic continuous process,which was proved by the analysis of the thermal degradation kinetics.And the difference between that was caused by the non-thermal effect of microwave.