Synthesis Of Sugar-based Carbon Dioxide-philic/Hydrophilic Surfactant And Preparation Of Macroporous Materials

Supercritical carbon dioxide?sc-CO₂?or liquid carbon dioxide?L-CO₂?can be used as an alternative solvent to conventional solvents because of its non-toxic,non-pollution,natural,low price,inert and environment-friendly to decrease the pollution from organic solvent or residual organic solvents in polymer materials.However,most of materials such as polar-substance,the high molecular polymer et al can't dissolve into it as the CO₂ belongs to weak solvent.In order to expand the application scope,an excellent route can be taken to improve the dispersion of polar substances,or the high molecular polymers by synthesizing CO₂-philic/ hydrophilic amphiphilic surfactant or dispersing agent.Carbon-hydrogen based materials with low-price and environment-friendly is a kind of alternative material,which has been widely studied,such as poly?vinyl acetate?,ether,et al.One of the best methods is often taken to develop these CO₂-philic materials by linking CO₂-philic group to the structure of molecular,which can make the molecular showing CO₂-philic character.The majority of carbohydrates belongs to the hydroxy aldehyde,or polyhydroxy ketones with low price,environment-friendly,and good biocompatibility,and have been widely used in medicine,tissue engineering materials,biological materials,and other fields.These materials can be modified by the method described above,and change into CO₂-philic materials.In this paper,the monosaccharide or polysaccharide was designed and synthesized to novel CO₂-philic/hydrophilic amphiphilic surfactant or carbohydrates-based macromolecular monomer by proper modifying using CO₂-philic group or vinyl monomer,and then prepared the carbohydrates-based macroporous materials by emulsion-template method.The details are as follows:Firstly,under the catalyst of boron trifluoride,the pentaacetylated galactose is reacted with 2-hydroxyethyl acrylate,and gets an acetylated saccharide-based monomer?2-?2?,3?,4?,6?-Tetra-O-acetyl-?-D-galactosyloxy?ethyl Acrylate?AcGalEA??.AcGalEA is polymerized by ATRP?Atom Transfer Radical Polymerization?using ethyl bromoacetate as the initiator,and obtains the corresponding polymers with degree of polymerization from 7 to 11 characterized by 1H NMR.Secondly,PEG is reacted with 2-bromopropionyl bromide to obtain the 2-bromopropionic acid poly?ethylene glycol?ester?Br-PEG-Br?,and then Br-PEG-Br was used as the macromolecular initiator to intiate the polymerization of AcGalEA by ATRP.A triblock polymer 2-?2?,3?,4?,6?-Tetra-O-acetyl-?-D-galactosyloxy?ethyl acrylate-b-polyethylene glycol-b-2-?2?,3?,4?,6?-Tetra-O-acetyl-?-D-galactosyloxy?ethyl acrylate?PAcGalEA-PEG-PAcGalEA?is yield.The PAcGalEA-PEG-PAcGalEA containing PEG group?hydrophilic?and PAcGalEA?CO₂-philic?is used as the surfactant to prepare the HIPE?high internal phase emulsion?80%,v/v??,and investigates the stability in the CO₂/water system,the results showed that the surfactant with a degree of polymerization of 3-5 was able to emulsify and stabilize the emulsion for more than half an hour.Finally,a starch-based macromolecular monomer?ST-MA?is synthesized by water-soluble starch reacting with methacrylic anhydride,which can dissolve into water.Using PAcGalEA-PEG-PAcGalEA and polyethylene glycol 1788 as the surfactant,the C/W HIPE?external phase containing PAcGalEA-PEG-PAcGalEA,and internal phase containing CO₂?was obtained.After polymerizing the external phase,the starch-based macroporous materials are yielded.All the macroporous materials are measured by SEM and the results show that the pore size of the macroporous materials are mostly between 3 and 11 ?m.