聚碳酸1,2-丙二酯的碱催化水解研究  

BASE CATALYZED HYDROLYSIS OF POLY(PROPLENE CARBONATE)

作　　者：马庆伟[1] 秦玉升[1] 赵晓江[1] 王献红[1] 王佛松[1] 

机构地区：[1]中国科学院长春应用化学研究所,长春130022

出　　处：《高分子学报》2010年第2期217-221,共5页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20634040)资助项目

摘　　要：研究了高分子量聚碳酸1,2-丙二酯的碱催化水解反应,并通过核磁共振谱仪和气相色谱质谱联用仪对降解反应产物的解析,发现碱催化聚碳酸1,2-丙二酯水解是无规断链反应和解拉链反应共同作用的结果.结果表明高分子量聚碳酸1,2-丙二酯的碱催化水解是制备低分子量聚碳酸1,2-丙二酯的方法之一.The base catalyzed hydrolysis reaction of poly（propylene carbonate）（PPC）,a highly alternative copolymer synthesized from carbon dioxide and propylene oxide,was investigated systematically in this report.The influences of reaction time,concentration of PPC solution,concentration of base（sodium hydroxide） solution,and residual zinc oxide on the degradation reaction were discussed.（）~1H-NMR spectra were used to analyze the carbonate unit content in the degraded polymer,it was found that the carbonate unit in the final degraded polymer maintained above 80% for all the studied conditions.The number average molecular weight of the final polymer dropped very quickly in the first several hours,a 50% decrease was observed in the first 2～6 h,depending on the concentration of PPC.The higher concentration of PPC was,the slower the decrease in molecular weight,when the concentration of PPC was 0.1 g/L,the number average molecular weight of the final polymer was 18500 after 8 h at 50℃,whereas it was 33700 when the PPC concentration was 0.5 g/L.Degradation time and base concentration were the two important factors for the yield as well as carbonate unit content in the degraded polymer,when the base concentration was 0.25 mol/L,the polymer yield maintained above 90% with carbonate unit over 80% at 48 h,the polymer yield dropped to ca.60% when the base concentration increased to 2.0 mol/L.Generally,prolonged degradation time caused yield loss in the final polymer,and the degradation reaction was enhanced with increasing base concentration.Compared with the purified PPC sample,the existence of zinc oxide in the as-polymerized PPC led to more severe degradation reaction.The GC-MS spectra were used to analyze the liquid compounds of the degraded products,where 1,2-isopropane-diol and propylene carbonate were detected,therefore,it was concluded that the random degradation reaction dominated in the base catalyzed degradation reaction at first stage,however,the un-zipping degradation reaction became dominant with th

关 键 词：聚碳酸1 2-丙二酯 碱催化水解 低分子量聚碳酸1 2-丙二酯 

分 类 号：O631.3[理学—高分子化学]