RAFT Polymerization of N-Isopropylacrylamide in the Absence and Presence of Y(OTf)3: Simultaneous Control of Molecular Weight and Tacticity
RAFT Polymerization of N-Isopropylacrylamide in the Absence and Presence of Y(OTf)3: Simultaneous Control of Molecular Weight and Tacticity
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DOI：
10.1021/ma035119h
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发表时间：
2004-02
期刊：
影响因子：
5.5
通讯作者：
B. Ray;Y. Isobe;Kozo Matsumoto;S. Habaue;Y. Okamoto;M. Kamigaito;M. Sawamoto
中科院分区：
文献类型：
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作者：
B. Ray;Y. Isobe;Kozo Matsumoto;S. Habaue;Y. Okamoto;M. Kamigaito;M. Sawamoto
以苯二硫代乙酸苯乙酯（PEPD）和苯二硫代乙酸枯酯（CPDT）为RAFT试剂，在无和有刘易斯酸Y（OTf）3存在下，成功地进行了N-异丙基丙烯酰胺（NIPAM）的可逆加成-断裂链转移（RAFT）聚合，合成了分子量可控的无规和全同立构聚（NIPAM）.在刘易斯酸存在下的聚合速率比在不存在下的聚合速率快约16倍，并且用PEPD作为RAFT试剂比用CPDT快1.4倍。当有刘易斯酸存在时，得到的聚合物具有更高的多分散性比在没有的情况下。观察到使用CPDT比PEPD的诱导期更长。全同立构聚（NIPAM）的链端结构通过1H NMR和MALDI-TOF质谱测定。从RAFT聚合机理可以看出，由RAFT试剂衍生的等规聚（NIPAM）是主要产物。此外，一系列立体嵌段[无规立构（...
The reversible addition−fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) was carried out successfully in the absence and presence of Lewis acid Y(OTf)3 to synthesize controlled molecular weight atactic and isotactic poly(NIPAM)s using both 1-phenylethyl phenyldithioacetate (PEPD) and cumyl phenyldithioacetate (CPDT) as the RAFT agents. The polymerization rate is about 16 times faster in the presence of the Lewis acid than that in the absence and 1.4 times faster with PEPD than with CPDT as the RAFT agent. The polymer with a higher polydispersity was obtained when prepared in the presence of the Lewis acid than that in the absence. A longer induction period was observed using CPDT than PEPD. The chain-end structure of isotactic poly(NIPAM) was determined by 1H NMR and MALDI−TOF mass spectrometry. The RAFT agent derived isotactic poly(NIPAM) was the main product as expected from the well-accepted mechanism of RAFT polymerization. Moreover, a series of stereoblock [atactic(...