Study On Cyclic And Linear-dendritic Block Copolymers Based On N-vinyllactam

Poly?N-vinylcaprolactam??PNVCL?and poly?N-vinylpyrrolidone??PNVP?are N-vinyllactam polymers with good water soluble,biocompatible and chemical stability.PNVCL and poly?2-?2-methoxyethoxy?ethyl methacrylate??PMEO₂MA?are thermoresponsive polymers.PNVCL displays a lower critical solution temperature?LCST?in the physiological range.Cyclic polymers and linear-dendritic block copolymers are topological macromolecules.Due to the absence of terminal groups,cyclic polymers have many special properties compared to linear analogues.Linear-dendritic block copolymers have the advantages of linear dendritic polymers and dendritic polymers.Their micelles are more stable.Thus,these polymers are promising for biomedical applications.However,at present,there are no reports on cyclic PMEO₂MA-based polymers and linear-dendritic block copolymers with PNVP as linear chains.In this thesis,cyclic poly?2-?2-methoxyethoxy?ethyl methacrylate??c-PMEO₂MA?homopolymer and cyclic poly?2-?2-methoxyethoxy?ethyl methacrylate?block copolymers?c-PMEO₂MA-b-PNVCL?were synthesized by atom transfer radical polymerization?ATRP?combined with Cu?I?catalyzed alkyne azide?CuAAC?click reaction at high concentrations?10 mg/mL?.The structure of the polymers were determined by GPC-MALLS,¹H NMR and IR.The properties of the polymers were studied.The results show that the topological structures do not affect the LCST of the polymers.c-PMEO2 MA can self-assemble to form smaller micelles in aqueous solution and possesses lower critical micelle concentration?CMC?compared with its linear analogue.The LCST and CMC of c-PMEO₂MA-b-PNVCL increase with the proportion of PNVCL block increase.The LCST and CMC of c-PMEO₂MA-b-PNVCL are lower than those of its linear analogue l-PMEO₂MA-bPNVCL.The particle size of c-PMEO₂MA-b-PNVCL was larger than that of l-PMEO₂MA-b-PNVCL.These polymers self-assemble into spherical micelles.Amphiphilic linear-dendritic block copolymers based on linear PNVP and dendritic phenylalanine and lysine was synthesized by macromolecular design viainterchange of xanthates/reversible addition-fragmentation chain transfer polymerization?MADIX/RAFT?combined with peptide synthesis.The structure of the polymers were determined using GPC-MALLS and1 H NMR.Their self-assembly properties in aqueous solution were studied.The results show that the CMC of the copolymers decrease with the hydrophobic dendrons increase.The copolymers self-assemble into spherical micelles.PNVP-b-G2 micelles in aqueous solution with particle size are less than PNVP-b-G3.