二氧化碳-环氧丙烷-丙交酯三元共聚物的合成与表征及其热解动力学研究

通过二氧化碳(CO2)、环氧丙烷(PO)与D,L-丙交酯(D,L-LA)的三元开环共聚,得到一种新型热塑性脂肪族聚碳酸酯(PPCLA).对PPCLA结构进行了FTIR、1H-NMR、13C-NMR及1H-1H COSY表征,表明D,L-LA开环嵌入PO-CO,分子链中,并对共聚过程聚合机理进行了初步探讨.同时设计并引入...

SYNTHESIS,CHARACTERIZATION AND THERMAL DEGRADATION KINETICS OF CARBON DIOXIDE-PROPYLENE OXIDE-D,L-LACTIDE TERPOLYMER

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 kJ·mol-1 and 140.3 kJ·mol-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.