Study On Synthesis Of Chain-end Functionalized Polyolefins Based On Polyhomologation Of Ylide

In recent years, the discovery of new synthetic methodology and the application of combined strategy based on living polymerizations have become a hot topic of current researches in the functionalization of polyolefin field. Firstly, polyhomologation of ylide which is a new synthetic methodology of constructing skeleton of molecular chain and thiol-ene click chemistry, are briefly introduced. Then, polymethylene achieved by polyhomologation of ylide, reacted with other functional reagents, to futher realize functionalization of polyolefin.In this paper, a series of hydroxyl-terminated polymethylenes(PM-OH) with different molecular weight(Mn) and narrow molecular weight distributions(PDI) were prepared by polyhomologation of ylide. The proton nuclear magnetic resonance(1H NMR), fourier transform infrared spectroscopy(FT-IR) and gel permeation chromatography(GPC) were employed to determine their chain structures, Mn and PDI.Then, we prepared novel initiators by hydroboration of alkylborane with diene/triene for polyhomologation of ylide, polymethylenes with functional chain-end groups were obtained. After oxidation, telechelic polymethylenes with functional group were successfully synthesized. The sructures were characterized by 1H NMR and FT-IR.Hydroxyl-terminated telechelic polymethylenes were converted to carboxyl-terminated via the esterification using succinic anhydride with4-(dimethylamino)pyridine(DMAP) as catalyst. 1H NMR and FT-IR after the reaction witnessed the successful introduction of carboxyl group.Finally, we used 3-mercapto-1,2-propanediol and thioglycolic acide with allyl end-functional polymethylenes, respectively, performing the thiol-ene click reaction in the presence of benzoin dimethyl ether(DMPA), successfully functionalized polyolefin.The sructures were characterized by 1H NMR and FT-IR.