高内相乳液模板法制备淀粉基大孔材料及表征
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摘要
首先将水溶性淀粉结构中的部分羟基用甲基丙烯酸酐功能化,得到淀粉基大分子单体(S-MA);然后以聚乙烯醇-1788为表面活性剂、以二氧化碳为分散相、以S-MA的水溶液为连续相,制备了水包二氧化碳型高内相乳液(内相体积分数大于74.05%);最后利用乳液模板聚合法制备了大孔材料。采用傅里叶变换红外光谱仪(FT-IR)、核磁共振波谱仪(~1H-NMR)、扫描电镜(SEM)等分析测试手段对S-MA的结构、大孔材料的孔径及分布进行了表征,研究了内相体积分数对材料孔径的影响。结果表明:所得高内相乳液具有优良的稳定性,能够稳定存在超过24h;所得大孔材料的平均孔径在10μm以上,且存在相互贯穿的孔结构,该结构有利于细胞的黏附和生长。
Liquid or supercritical carbon dioxide(LCO_2 or sc-CO_2)is an alternative green solvent to coventional organic solvents because of its nontoxic,non-flammable,and non-expensive,characteristics to prepare the CO_2-in-water high internal phase emulsion(C/W HIPEs,the internal phase volume fraction≥74.05%).The C/W HIPEs emulsion can be used to produce the macroporous materials with special construction by the emulsion-templating polymerization method.Using this method,a novel starch-based macroporous material was produced.Firstly,the starch-based macromolecular monomer(S-MA)was synthesized by esterifying the soluble starch with methacrylic anhydride,and its structure was characterized by ~1H-NMR and FT-IR.Then the C/W HIPEs emulsion was prepared using poly(vinyl alcohol)-1788 as the surfactant,CO_2 as the internal phase,and S-MA solution as the continuous phase.The stability of emulsion was also investigated.The results indicated that the C/W HIPEs emulsion was stable for more than 24 h,whether or not S-MA in presence,even if the internal phase volume fraction took up to 90% and the surfactant mass concentration was as low as 2×10~(-3) g/mL.Good stability of HIPEs was necessary to get macroporous materials for the following polymerization of the continuous phase.After the continuous phase was polymerized using the potassium persulfate/N,N,N′,N′-tetramethylethylenediamine as the redox initiation system,starch-based macroporous materials with uniform monolithic materials in the cylindrical interior of the cell were recovered,suggesting no significant shrinkage after the CO_2 venting.SEM analysis shows that pore-size of these macroporous materials is above 10μm with open-cell morphology,and these pores can be controlled easily by changing the volume ratio of internal phase and the continuous phase.These simple structure features of these materials supported cell growth and proliferation for tissue engineering applications.
Liquid or supercritical carbon dioxide(LCO_2 or sc-CO_2)is an alternative green solvent to coventional organic solvents because of its nontoxic,non-flammable,and non-expensive,characteristics to prepare the CO_2-in-water high internal phase emulsion(C/W HIPEs,the internal phase volume fraction≥74.05%).The C/W HIPEs emulsion can be used to produce the macroporous materials with special construction by the emulsion-templating polymerization method.Using this method,a novel starch-based macroporous material was produced.Firstly,the starch-based macromolecular monomer(S-MA)was synthesized by esterifying the soluble starch with methacrylic anhydride,and its structure was characterized by ~1H-NMR and FT-IR.Then the C/W HIPEs emulsion was prepared using poly(vinyl alcohol)-1788 as the surfactant,CO_2 as the internal phase,and S-MA solution as the continuous phase.The stability of emulsion was also investigated.The results indicated that the C/W HIPEs emulsion was stable for more than 24 h,whether or not S-MA in presence,even if the internal phase volume fraction took up to 90% and the surfactant mass concentration was as low as 2×10~(-3) g/mL.Good stability of HIPEs was necessary to get macroporous materials for the following polymerization of the continuous phase.After the continuous phase was polymerized using the potassium persulfate/N,N,N′,N′-tetramethylethylenediamine as the redox initiation system,starch-based macroporous materials with uniform monolithic materials in the cylindrical interior of the cell were recovered,suggesting no significant shrinkage after the CO_2 venting.SEM analysis shows that pore-size of these macroporous materials is above 10μm with open-cell morphology,and these pores can be controlled easily by changing the volume ratio of internal phase and the continuous phase.These simple structure features of these materials supported cell growth and proliferation for tissue engineering applications.
引文
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[15]LUO W,ZHANG S,LI P,et al.Surfactant-free CO2-in-water emulsion-templated poly(vinyl alcohol)(PVA)hydrogels[J].Polymer,2015,61:183-191.
[16]LEE J,TAN B,COOPER A I.CO2-in-water emulsion-templated poly(vinyl alcohol)hydrogels using poly(vinyl acetate)-based surfactants[J].Macromolecules,2007,40(6):1955-1961.
[17]FRINGANT C,DESBRIERES J,RINAUDO M.Physical properties of acetylated starch-based materials:Relation with their molecular characteristics[J].Polymer,1996,37(13):2663-2673.
[18]ANNABI N,MITHIEUX S M,WEISS A S,et al.Cross-linked open-pore elastic hydrogels based on tropoelastin,elastin and high pressure CO2[J].Biomaterials,2010,31(7):1655-1665.
[2]CHRISTENSON E M,SOOFO W,HOLM J L,et al.Biodegradable fumarate-based polyHIPEs as tissue engineering scaffolds[J].Biomacromolecules,2007,8(12):3806-3814.
[3]DAVIES O R,LEWIS A L,WHITAKER M J,et al.Applications of supercritical CO2in the fabrication of polymer systems for drug delivery and tissue engineering[J].Advanced Drug Delivery Reviews,2008,60(3):373-387.
[4]任会婷,王正宫,张丰,等.孔PI气体分离膜的研究进展[J].功能高分子学报,2016,29(4):377-387.
[5]CHEN Y,BALLARD N,BON S A F.Moldable high internal phase emulsion hydrogel objects from non-covalently crosslinked poly(N-isopropylacrylamide)nanogel dispersions[J].Chemical Communications,2013,49(15):1524-1526.
[6]YOUSSEF C,BACKOV R,TREGUER M,et al.Preparation of remarkably tough polyHIPE materials via polymerization of oil-in-water HIPEs involving 1-vinyl-5-aminotetrazole[J].Journal of Polymer Science:Part A.Polymer Chemistry,2010,48(13):2942-2947.
[7]DESIMONE J M.Practical approaches to green solvents[J].Science,2002,297(5582):799-803.
[8]BOYERE C,LEONARD A F,GRIGNARD B,et al.Synthesis of microsphere-loaded porous polymers by combining emulsion and dispersion polymerisations in supercritical carbon dioxide[J].Chemical Communications,2012,48(67):8356-8358.
[9]BUTLER R,DAVIES C M,COOPER A I.Emulsion templating using high internal phase supercritical fluid emulsions[J].Advanced Materials,2001,13(19):1459-1463.
[10]PSATHAS P A,ROCHA S R P D,LEE C T,et al.Water-in-carbon dioxide emulsions with poly(dimethylsiloxane)-based block copolymer ionomers[J].Industrial&Engineering Chemistry Research,2000,39(8):2655-2664.
[11]CHEN K,GRANT N,LIANG L,et al.Synthesis of CO2-philic xanthate-oligo(vinyl acetate)-based hydrocarbon surfactants by RAFT polymerization and their applications on preparation of emulsion-templated materials[J].Macromolecules,2010,43(22):9355-9364.
[12]TANB,LEE J,COOPER A I.Synthesis of emulsion-templated poly(acrylamide)using CO2-in-water emulsions and poly(vinyl acetate)-based block copolymer surfactants[J].Macromolecules,2007,40(6):1945-1954.
[13]ZHANG S,LUO W,YAN W,et al.Synthesis of a CO2-philic poly(vinyl acetate)-based cationic amphiphilic surfactant by RAFT/ATRP and its application in preparing monolithic materials[J].Green Chemistry,2014,16(9):4408-4416.
[14]SARBU T,STYRANCE T J,BECKMAN E J.Design and synthesis of low cost,sustainable CO2-philes[J].Industrial&Engineering Chemistry Research,2000,39(12):4678-4683.
[15]LUO W,ZHANG S,LI P,et al.Surfactant-free CO2-in-water emulsion-templated poly(vinyl alcohol)(PVA)hydrogels[J].Polymer,2015,61:183-191.
[16]LEE J,TAN B,COOPER A I.CO2-in-water emulsion-templated poly(vinyl alcohol)hydrogels using poly(vinyl acetate)-based surfactants[J].Macromolecules,2007,40(6):1955-1961.
[17]FRINGANT C,DESBRIERES J,RINAUDO M.Physical properties of acetylated starch-based materials:Relation with their molecular characteristics[J].Polymer,1996,37(13):2663-2673.
[18]ANNABI N,MITHIEUX S M,WEISS A S,et al.Cross-linked open-pore elastic hydrogels based on tropoelastin,elastin and high pressure CO2[J].Biomaterials,2010,31(7):1655-1665.