Living Cationic Polymerization From Sulfenyl Chloride

Living cationic polymerization is widely used due to its high polymerization rate and high conversion rate.Some industrial products such as rubber can only be obtained by cationic polymerization,so cationic polymerization plays an important role in industrial production.The cationic polymer with functional group plays an important role in the synthesis of telechelic polymers,macromonomers and other aspects.So far all cationic polymerizations have been initiated by alkyl halides,which have a single initiation system,complicated synthesis methods,and few types of functionalized initiators,and alkyl halideshave great limitations on the development of cations.The reaction of sulfenyl chloride for the formation of sulfonium ions by double bond has long been matured in organic chemical reactions,and the synthesis of sulfenyl chloride compounds is simple.Up to now,sulfenyl chloride compounds have not been used for cationic polymerization.In this paper,by using a sulphur chloride compound as an initiator and SnCl4 as a living cationic polymerization of a Lewis acid,the following work was carried out:Through a series of conditions screening,that is Sulfenyl chloride was used as the initiator,then SnCl4 was used as the Lewis acid at-78 ?,the optimal conditions were obtained.This system can initiate "living" cationic polymerization.The polymer obtained using a variety of sulfenyl chloride initiators has a narrow molecular weight distribution(less than 1.28)and number-average molecular weight close to the theoretical molecular weight.By the coversion of monomer,polymers of different molecular weights can be obtained.I also studied monomer suitability,and sulfenyl chloride initiators provide excellent control over the polymerization of commonly used vinyl ether monomers.The controllability of the system was proved by chain extension experiments.Through the analysis of maldi-tof mass spectrometry and1H NMR spectrum,I found that the polymer chain end synthesized by this system has good fidelity and obtained a series of vinyl ether polymer with terminal functional groups lays the foundation for subsequent cationic development.I have established a new cationic polymerization system with sulfenyl chloride as the initiator,and obtained eight kinds of chain-end isobutyl vinyl ether polymers.I conducted polymerization experiments on four different monomers,and the results met the expected goals.