Hybrid Polymer Materials Based On Polyestertriazoles And Polymerical Cryogels

Different materials provide the substantial foundation for human society development as well as technology improvement.According to the physical/chemical properties,materials are commonly catagorized into inorganic,metal and polymeric materials,being used in various related fields.In the current age of rapid development of science and technology,researchers have been devoting their efforts to obtain different materials with outstanding performance and excellent adaptability through the integration of different kinds of material and the modulation of hierarchical structures at micro-,meso-and macro-sized levels,and managing to achieve this ultimate goal.Hybrid materials,composed of polymer materials and inorganic or metal materials,integrate the soft,easy-processing characteristics from polymer materials and the hard,strong properties from metal/inorganic materials together.Thus,hybrid materials have been attracting lots of research interest in different fields.In this thesis,hyperbranched polyestertriazoles and polymer cryogels are separately chosen as the matrix of hybrid materials to construct hybrid nano-sized materials and porous hybrid materials.Their applications in the areas of detecting metal ions,reaction catalysis,energy conversion and skincare masks are investigated.Meanwhile,the correlation among the composition,structure and performance of those obtained hybrid materials is under consideration.The research work is mainly disclosed as below.Part One:Hybrid nano-particles based on hyperbranched polyestertriazoleAzido-alkynyl click reaction is highly efficient and rapid while the resulted triazole group provides the resulted polymeric materials with certain physicochemical properties.So it has been widely used in synthetic chemistry to obtain various materials with different components and architectures.Herein,one small molecule having one alkynyl group and two sulfonyl groups is designed and synthesized.With this compound as the pre-monomer of azido-alkynyl click polymerization,the group transformation from sulfonyl to azido group and the click reaction are performed concurrently in the presence of sodium azide,resulting in hyperbranched polyestertriazole(hb-PETA).Then,hb-PETA is modified by grafting and crosslinking through terminal azido groups to obtain hyperbranched polyestertriazole graft copolymer as soft template and core-crosslinked microgel as micro-reactor,respectively.After the incorporation of metal nanoparticles,those hybrids as the catalyst for the reduction of p-nitrophenol and important organic reactions are inversitgated.1.Synthesis of hyperbranched polyestertriazole and their detection of metal ionsPropargyl(2,2-bismethylsulfinyloxymethyl)propionate as AB2 pre-monomer is designed and successfully synthesized.In the presence of sodium azide,the spontaneous group transformation and azido-alkynyl click reaction are carried out to produce hyperbranched polyestertriazole(hb-PETA)in one stage.This polyestertriazole synthesis route leaves the purification of azido compound and avoids the danger upon handling it.By the aid of proton nuclear magnetic resonance spectroscopy,the whole synthesis kinetics is monitored considering the group conversion and the molecular weight of hb-PETA.It should be emphasized that those polyestertriazoles exhibit photoluminescence ability,being dependent on the used solvent medium as well as the type and amount of metal ions chelated by hb-PETA.Thus,their detect performance for Hg2+ ion in water is studied and confirmed to be very effective.2.Synthesis of hybrid gold nanoparticles with hb-PETA-g-PNIPAM and their catalysis for pollution compound removalAlkynyl-capped poly N-isopropylacrylamide(alkynyl-PNIPAM)with narrow moelcular weight distribution and temperature responsive behavior is synthesized through atom transfer radical polymerization and grafted onto the above hb-PETA,who has many peripheral azido groups,through azido-alkynyl click reaction.The obtained hyperbranched-graft copolymers of hb-PETA-g-PNIPAM,in the absence of any additional reductant and stabilizing reagent,can reduce the gold precursor of HAuCl4 into gold nanoparticles to form the stable hybrid gold nanoparticles with hb-PETA-g-PNIPAM(AuNPs/hb-PETA-g-PNIPAM).The investigation results disclose that the morphology of AuNPs varies from nano-sphere to nano-wire,being dependent on the reaction temperature and the ratio of HAuCl4 to hb-PETA-g-PNIPAM.Those hybrid AuNPs/hb-PETA-g-PNIPAM dispersions can stand at room temperature for 3 months without any aggregation and sediment.Above lower critical solution temperature of PNIPAM,those hybrid AuNPs/hb-PETA-g-PNIPAM precipitate because of PNIPAM aggregation,exhibiting thermal response.Those hybrid AuNPs/hb-PETA-g-PNIPAM efficiently convert p-nitrophenol into p-aminophenol with NaBH4 in aqueous solution at room temperature.3.Hybrid microgels composed of hb-PETA-g-PNIPAM and gold or palldium nanoparticles and their catalytic propertyTo solve the inconvnience of storing and using hyperbranched-graft copolymers hybrid nanoparticles,hb-PETA-g-PNIPAM is crosslinked with one small molecule having four alkynyl groups to obtain microgels,which are stably dispersed in aqueous media.Furthermore,those microgels loaded with gold or palladium to produce hybrid microgels are used as catalyst for organic reactions.As expected,those hybrid microgels exhibit the temperature-dependent swelling and de-swelling behavior as well as the stable and uniform dispersion in aqueous media.The catalytic performance of those hybrid microgels for Suzuki reaction and p-nitrophenol reduction is studied,demonstrating high catalytical activities.Due to crosslinkage,the leakage of metal nanoparticles is restricted,maintaining the catalystical activity during the usage.Moreover,those hybrid microgels can be recycled by heating precipitation.Part Two.Hybthe rid materials based on polymer cryogelsPolymer cryogels are porous materials with inter-connected macropores and obtained through the crosslinking polymerization of different monomers or the crosslinkage of polymeric precursors at the temperatures below the freezing point of reaction mixture.Compared with common gels prepared under non-frozen state,cryogels have much larger pore size,inter-connected pore pathway and more parameters to modulate the pore morphology to achieve some special performance.Thus,their increasing applications in the fields of separation/absorption,catalyst carrier,biomedical materials and energy conversion attract more and more attention from researchers.4.Hybrid cryogels of ampholytic copolymers and montmorillonite as moisture-keeping facemaskCryogel-type facemask is used for the skincare and should have excellent moisture-keeping ability,comfortable softness and necessary strength.However,polymeric cryogels with open macropores is a little weak in their strength.Montmorillonite is one kind of two-dimensional lamellar inorganic mineral and has excellent hydrophilicity.Through intercalation copolymerization with ampholytic vinyl monomers,the obtained ampholytic polymeric cryogels can be strengthened.Thus,montmorillonite is intercalated with N-(3-sulfopropyl)-N-methacroyloxyethyl-N,N-dimethylammonium betaine in aqueous solution and the following cryogenic copolymerizations with 2-hydroethyl methacrylate are carried out to produce hybrid cryogels composed with ampholytic copolymers and montmorillonite with high mechanic strength.The results of biotoxicity,swelling study,moisture evaporation rate of the hybrid gel all indicate that those hybrid cryogels have the ability to hand-handle and the excellent skin compatibility.Within 10 sec,the saturated water-absorption can be reached with the absorption capacity of 18.46 g/g.The water evaporation from the wet hybrid cryogels is determined to be seriously limited due to the cryogel features,endowing the hybrid cryogels to be used in the moisturizing facemasks.By the combination of sodium alginate fiber mask paper and the integrated molding technology with facial mold,the full-sliced and hand-handling facemasks with good moisturizing performance are obtained.5.Electrically conductive hybrid cryogels of polyaniline/polyacrylamide and their electrochemical propertyThe hierarchical porous structure of polymeric cryogels offers more possibilities to modulate the transport pathway of current carrier,enabling the wide application of cryogels as the matrix in the secondary cells and super-capacitors.The intergration of polymeric cryogel matrix and electro-active component,especially the distribution of electro-active component in polymeric cryogel matrix,is the key point to influence the performance of those electric devices.As for polyaniline,through the synchronic occurrence of radical cryo-polymerization of acrylamide and oxidative coupling cryo-polymerization of aniline as well as the variation of crosslinking agents,polyaniline cryogels with permanent chemical crosslinkage and dynamic physical crosslinkage are prepared separately.With the aid of electron microscopy,the distribution of polyaniline in polyacrylamide cryogels is proved to be homogeneous,mostly as thin layer on the cryogel wall.The electrochemical properties of their carbon cloth hybrid electrode are determined,disclosing that the chemically crosslinked hybrid cryogels have the characteristics of high cyclic stability and low specific capacitance,while the physically crosslinked hybrid cryogels have the characteristics of higher specific capacitance and low cyclic stability,being adaptably used in different working conditions.This research testifies the unique advantage of cryo-polymerization in the one-step preparation of electro-active hydrogels with homogeneous distribution and provide alternative guide to the design of supercapacitor materials and devices.