The Synthesis And Functionalization Of Hyperbranched Polyesters And Their Photosensitive Properties

Hyperbranched polymers have been an important field for research and applications of polymer science in resent years.They own highly branched molecular structures,perform special physical and chemical properties,and can be easily synthesized,relatively.Because of their large number of surface functional group,they are also facile for chemical modification.Moreover,photosensitive hyperbranched polymer also becomes the focus of polymer scientists.In this doctoral dissertation different terminal functionalized hyperbranched polyester were synthesized and applied in photo crosslinking and photo responsive systems. Furthermore,a series of hyperbranched poly(thiol ether-ester) polyol with relatively high degree of branching were synthesized through UV induced "thiol-ene" reaction.1.Terminal functionalized hyperbranched polymers and their photopolymerization behaviors in "thiol-ene" UV curing systemsHyperbranched polyester polythiol,TAH40,was prepared by thiol modification of Boltron^? H40.And multi-ene hyperbranched polyester oligmers, including allyl ether terminal functionalized AEH20 and norbornene end-capped NCP1000,were also synthesized and characterized by ¹H NMR spectral analysis. The UV-induced photopolymerization behavior of binary thiol-ene system was real-time monitored with Photo-DSC in air.The UV photo reactivity of obtained thiol-ene systems was also evaluated.2.Thiol functionalized hyperbranched polyesters and their application in photoinitiator-free "thiol-acrylate" photopolymerization systemHyperbranched polythiol polyester TAH20 and TAP1000 were synthesized by surface modification of Boltron^? H20 and P1000 and characterized by ¹H NMR spectral analysis.And obtained polythiol were used in photoinitiator-free "thiol-acrylate" systems with different multi-functional acrylate monomers.The UV induced photopolymerization of "thiol-acrylate" systems was evaluated by Photo-DSC method.The "thiol-acrylate" system performed very high photosensitivity and cured very fast under UV irradiation without addition of photoinitiator in air atmosphere.3.4-Methyleoumarin terminally funetionalized hyperbranehed polester and its reversible photo responsive propertiesHyperbranched polymer with 4-methylcoumarin terminal group(MCTH40) was prepared via thiol-ene addition reaction of thiol-modified hyperbranched polyester TAH40 and a vinyl monomer(7-(4-vinyl-benzyloxyl)-4-methylcoumarin,VBMC), and characterized with ¹H NMR and FT-IR spectroscopy.Its reversible photo-crosslinking/photo-cleavage behavior was evaluated based on the UV-Vis and FL spectroscopic analysis,and compared with the linear polymer,PVBMC.4.7-hydroxycoumarin terminally funetionalized hyperbranehed polyester and its reversible photo and pH responsive propertiesThe 7-hydroxycoumarin terminal functionalized hyperbranched polyester, HCTH40,was prepared via thiol-ene addition between TAH40 and an acrylate 7-hydroxycoumarin monomer,EGCA.The product was characterized with ¹H NMR and FT-IR spectroscopy.Its reversible photo responsive behavior and the pH-dependent fluorescence emitting property were investigated by UV-Vis, fluorescence spectral and GPC analysis.The results indicated that the HCTH40 performed relatively steady photo reversibility and pH responsive behavior. 5.Syntheis of hyperbranched poly(thiol ether-ester) polyol through "thiol-ene" addition methodHyperbranched poly(thiol ether-ester) polyols(PTE[OH]) were synthesized by combined thiol terminal functionalization and "thiol-ene" addition reaction. PTE[OH]-A1 and B1 were synthesized by "thiol-ene" between two multi-functional thiol monomers and a new vinyl benzyl ester(BMPVB),respectively.Furthermore, PTE[OH]-A2,B2,A3,and B3,were synthesized by successive reactions of thiol glycolic acetate esterification and "thiol-ene" photo addition.The products were characterized with ¹H NMR,FT-IR and GPC methods.And the analysis results reflected that obtained hyperbranched poly(thiol ether-ester) polyol owned high degree of branching.