通过在线~7Li-NMR谱对负离子聚合见解的进一步验证

通过对正丁基锂(n-BuLi)/四氢呋喃(THF)引发α-甲基苯乙烯(mSt)负离子本体聚合,验证了n-BuLi缔合体可以引发聚合,形成超分子团聚体,然后在进一步聚合过程中超分子解离.证实了先前提出的负离子聚合的引发机理.通过7Li-NMR对聚合过程的在线检测,进一步证实了mSt在氘代苯为溶剂,THF为调节剂下的负离子聚合以及异戊二烯在非极性条件下的溶液聚合都存在引发剂多元缔合体向二元缔合体转变.研究还发现,少量THF可能使n-BuLi的六元缔合结构2～3个进一步串联起来,但先于六元缔合结构解离.此外,THF与n-BuLi作用,随着n-BuLi/THF的摩尔比从1∶1到1∶5的变化,可以使n-BuLi的巨大缔合体解离并向六元缔合体转变.

FURTHER CONFIRMATION OF THE ANIONIC POLYMERIZATION INSIGHT THROUGH in situ ~7Li-NMR SPECTRUM

It was further confirmed through the anionic bulk polymerization of α-methylstyrene(mSt) initiated by n-butyl lithium(n-BuLi)/tetrahydrofuran(THF) that the aggregators of n-BuLi could initiate anionic polymerization,which resulted in forming of the supramolecules,then these supramolecules would be dissociated during the further polymerization.The results have further verified the new initiating mechanism of anionic polymerization proposed previously.With the in situ 7Li-NMR during the polymerization of mSt under D-benzene as solvent,THF as regulator and n-BuLi as initiator,it was further confirmed that in the system,there existed a conversion process of the initiator aggregators from pluralistic aggregated structure to the binary one.Meanwhile,in situ 7Li-NMR of isoprene polymerization under D-benzene solution initiated by n-BuLi also verified the conversion process of the initiator aggregators.It was also found that when a small amount of THF was mixed in the mSt polymerization system,the two or three of hexameric aggregators might be connected by THF.However,these connected aggregators would be dissociated preceding that of hexameric aggregators themselves.Furthermore,with the increasing of n-BuLi/THF(mole ratio) from 1∶1 to 1∶5,the huge aggregators of n-BuLi could be changed into hexameric ones.