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摘要
The characteristics of depolymerization of polycarbonate (PC) in sub-critical water were investigated in the range of 260 similar to 340 degrees C and 5 similar to 60 min by using a high-pressure batch autoclave reactor. It was found that PC could be effectively depolymerized in sub-critical water. The main products were bisphenol A (BPA) and phenol, which were analyzed by FTIR, SEM, GC/MS and GC. It was found that the temperature and reaction time were important factors in the process of depolymerizaition. Swelling process of PC played an important role in this hydrolysis reaction, which occured in the region 280 similar to 300 degrees C accompanied by the remarkable hydrolysis. With the raising of the temperature and the reaction time, the yield of bisphenol A was increased at first and then reduced. Bisphenol A was unstable in the sub-critical water, it would further decompose into phenol, p-tert-butylphenol, p-isopropenylphenol etc. The result showed that at reaction temperature 300 degrees C, reaction pressure 8. 7 MPa and reaction time 45 min, the PC could be depolymerized completely with the yield of BPA and phenol were 36. 88% and 31. 16%, respectively. Based on the qualitative and quantitative analyses of the products, the reaction mechanism, i. e. random scission and hydrolytic reaction occurred simultaneously during the process of depolymerizaition of PC was proposed. The results of kinetic analysis indicated that the depolymerization followed a pseudo-first-order kinetics and the activation energy of PC depolymerizaition in sub-critical water obtained from Arrhenius equation was 125.7 kJ.mol(-1).
- 出版日期2011-3-20
- 单位浙江工业大学
