A novel terpolymer of carbon dioxide

propylene oxide (PO) and D

L-lactide (D

L-LA) was synthesized successfully at 70℃ in toluene by using a polymer-supported bimetallic complex (PBM) as a catalyst.The terpolymer prepared was characterized by FTIR

1H-NMR

13C-NMR and 1H-1H COSY spectrum measurements

which showed D

L-LA was ring-opened and inserted into the backbone of PO-CO2 with the fixed molar ratio of PO and D

L-LA as 5 ∶1. Furthermore

the expected reaction mechanism suggested the initiation of PO was more facile than that of CO2. Meanwhile

a new computational method called nonlinear approximation method was introduced in this work to analyse the thermal degradation kinetics.FWO and Tang methods as well as nonlinear approximation method were chosen to calculate the apparent activation energy.The results showed the accuracy of this new method was high and the average relative error was less than 6.5% due to its more scientific calculation process when Vyazovkin model free method was chosen as the standard method.During the whole degradation process

the apparent activation values ( Ea ) were between 66.6 kJmol-1 and 140.3 kJmol-1

indicating a better thermal stability related with the higher Ea as compared with that of PPC in the early decomposition stage.The results of non-isothermal degradation kinetics also suggested the whole pyrolysis of the terpolymer was a multi-step process due to variation of Ea .