三氟丙烯本体均聚及与乙烯类单体的溶液共聚合研究

以偶氮双异丁腈(AIBN)作引发剂,研究3,3,3-三氟丙烯(TFP)的本体均聚及其在超临界二氧化碳(sc-CO2)中与烯类单体如醋酸乙烯酯(VAc)、丙烯酸甲酯(MA)、苯乙烯(St)、异丁基乙烯基醚(IBVE)、丙烯酸(AA)5种单体的溶液共聚合反应,测定总单体转化率和TFP转化率随时间的变化及最终产物的平均分子量;对TFP与VAc在sc-CO2中的溶液共聚合除测定上述聚合参数外,采用红外光谱和19F-核磁共振谱表征共聚物的结构,应用核磁共振和电位分析法对比表征共聚物中TFP的结合量、共聚物数均分子量及其分布指数随TFP与VAc的物质的量比、TFP转化率的变化。结果表明:无论是本体聚合还是在sc-CO2中的溶液聚合,TFP都很难发生自由基均聚,但在sc-CO2中TFP却可与上述5种单体发生自由基共聚合,相同条件下50 h TFP的转化率顺序是:Y(TFP-VAc)Y(TFP-IBVE)Y(TFP-MA)≈Y(TFP-St)Y(TFP-AA)。对于TFP-VAc在sc-CO2中的共聚,发现有明显的交替共聚倾向,当n(TFP)∶n(VAc)0.5时,可获得n(TFP):n(VAc)接近1:1的交替共聚物。

Study on Homopolymerization of Trifluoropropene in Bulk and Copolymerization with Vinyl Monomers

The homopolymerization of 3,3,3-trifluorpropene(TFP) and copolymerization of TFP with 5 vinyl monomers including vinyl acetate (VAc),isobutyl viny ether(IBVE),methyl acrylate(MA),stylene(St) and acrylic acid(AA) in supercrical carbon dioxide(sc-CO2) by using azobisisobutryonitrile(AIBN) as initiator were studied.The structure ofas-prepared copolymer and its properties were characterized by FTIR,19F-NMR.The results showed that TFP was very difficult to homopolymerize in bulk or in sc-CO2 by using AIBN as initiator,but it was easy to copolymerize with vinyl monomers under same polymerization condition.Among the vinyl monomers,in the same condition,TFP conversion rate order was Y(TFP-VAc)>Y(TFP-TBVE) >Y(TFP-M)≈Y(TFP-ST)>Y(TFP-AA).Only the copolymerization of TFP-IBVE and TFP-VAc got the alternating copolymer in which the mol ratio of TFP and comonomers approached 1∶1.