Application Of1,3-diacetylene Structures In The Synthesis Of Star-shaped And Graft Polymers

With the rapid development of living/controlled polymerization mechanisms andefficient coupling methods, a variety of polymers with complicated architecture havebeen synthesized. Among them, the star-shaped and graft polymers have attractedmuch attention due to their unique properties and versatile applications in biomedicalmaterials, composite materials and supra-molecular science. In this work, series ofA2B4star-shaped and graft polymers were synthesized by derivations of1,3-diacetylene structures on polymers, and the detailed work are listed as follows:1. The amphiphilic star-shaped polymers [methoxy poly(ethyleneoxide)]2-[poly(ε-caprolactone)]4(mPEO2PCL4) and [methoxy poly(ethyleneoxide)]2-[poly(styrene)]4(mPEO2PS4) were successfully designed and synthesized.First, mPEO containing terminal alkyne （mPEO-Alkyne） was obtained bymodification of mPEO-OH with propargyl bromide. Then, the macroinitiatormPEO-(OH)4-mPEO was obtained by Glaser coupling and following thiol-ynereaction with mercaptoethanol under254nm UV irradiation. Finally, the star-shapedpolymer mPEO2PCL4was achieved by ring opening polymerization (ROP) ofε-caprolactone （ε-CL）monomers from mPEO-(OH)4-mPEO macroinitiator. Also,the hydroxyl group on mPEO-(OH)4-mPEO was reacted with2-bromoisobutyrylbromide, and star-shaped polymer mPEO2PS4was prepared by atom transfer radicalpolymerization (ATRP) of styrene (St) monomers. All the intermediates and targetproducts were characterized by GPC、1H NMR and MALDI-TOF MS measurementsin detail.2. The amphiphilic graft polymers PEO-g-PCL4were successfully designed andsynthesized. Firstly, Alkyne-poly(styrene)-Alkyne (Alkyne-PS-Alkyne) andAlkyne-poly(ethylene oxide)-Alkyne (Alkyne-PEO-Alkyne) were obtained bymodification of hydroxyl groups at PS and PEO ends with propargyl bromide. Then,the high molecular weight (PS-diyne-PS)sand (PEO-diyne-PEO)swith1,3-diynestructures were synthesized by Glaser coupling, and the diyne structures were further transferred into hydroxyl groups by efficient thiol-yne reaction with mercaptoethanol.Finally, the PEO-g-PCL4amphiphilic graft polymers were obtained by ROP of ε-CLmonomers from macroinitiator [PEO-(OH)4-PEO]s. All the intermediates and targetproducts were characterized by GPC、1H NMR and MALDI-TOF MS measurementsin detail. The crystallization behavior of PEO-g-PCL4with different PCL contentswere also investigated by DSC, WAXD and POM instruments.