Syntheses Of Fluorinated Polyurethane-based Triblock Copolymers Via ATRP And Their Properties

Studies on the modification and functionalization of polyurethane materials have been increasing in recent years.In this thesis,we adopted the strategy of generating triblock copolymer architecture aiming to improve the surface hydrophobicity of polyurethane materials and systematically study on the self-assembly,surface free energy and phase separation of triblock copolymers.First of all,ABA-type triblock copolymer PTFEMA-b-PU-b-PTFEMA consisting of fluorinated segments as A-block and polyurethane as B-block,was generated based on the successful synthesis of ATRP-initiating polyurethane macro initiator,during which processes the polymer was well characterized by IH-NMR and GPC.1H-NMR was conducted to characterize their molecular structure and calculate their molecular weight.Besides,the triblock copolymers were also characterized by SAXS,static contact angle,XPS and FT-IR in order to obtain the information of morphology,surface free energy and element compositions on the surface.The results demonstrated that as the ?PTFEMA increasing,the ability to self-assemble of triblock copolymers was enhanced as well as the ability of PTFEMA segments to aggregate on the surface,while the surface free energy was decreasing in contrary.When?PTFEMA=0.16,the copolymer started to self-assemble and formed a hole-like morphology in the bulk,the surface was almost covered with PTFEMA segments,the surface free energy was decreasing from 37.8 mJ/m2 with a?PTFEMA=0.04 to a lowest value of 25.2 mJ/m2,similar to that of PTFEMA homopolymer(23.7 mJ/m2).The conclusioi could be that the surface free energy of triblock copolymers was decreased because of the aggregation of PTFEMA segment on the surface,which was correlated to the ability to self-assemble of the copolymers.What's more,the triblock copolymers also showed electrophoretic deposition behavior,which was effected by the compositions of copolymers,the concentration of the copolymer emulsion and the selectivity of solvents.What should be emphasized here is that when ?PTFEMA?0.49,the deposition of copolymers on the cathode was a gel coating.