【《气体分离膜的交联处理研究文献综述》2200字】

气体分离膜的交联处理研究文献综述塑化是聚合物膜商品化的一个巨大障碍，对聚合物膜进行交联处理是目前被认为改善这一问题的有效方法。交联处理一般包括化学交联、UV交联和热诱导交联等方式。这些交联处理的目的是为了使聚合物链与链之间变得更加紧密，形成的交联网状结构可以使膜的内部结构更加稳定，能够在高压条件下防止高度可溶的气体把膜材料溶胀或塑化。化学交联图1-36FDA-durene与线性二胺分子的化学交联机理Fig.1-3Thechemicalcross-linkingmechanismof6FDA-dureneandlineardiaminemolecules化学交联一般是选用二胺或二醇等小分子作为交联剂，可以对含有羟基、羧基和氨基等官能团的聚合物进行化学反应交联。这种交联反应的优势是不仅可以在聚合物膜中形成网状结构优化膜内的链间距，而且还可以在交联结构中引入氢键改善聚合物的化学环境。Chung课题组采用化学交联的方式对聚酰亚胺气体分离膜进行改性处理[[]CAOC,CHUNGTS,LIUY,etal.Chemicalcross-linkingmodificationof6FDA-2,6-DAThollowfibermembranesfornaturalgasseparation[J].JournalofMembraneScience,2003,216(1-2):257-268.,[]LIUY,WANGR,CHUNGTS.Chemicalcross-linkingmodificationofpolyimidemembranesforgasseparation[J].JournalofMembraneScience,2001,189(2)[]CAOC,CHUNGTS,LIUY,etal.Chemicalcross-linkingmodificationof6FDA-2,6-DAThollowfibermembranesfornaturalgasseparation[J].JournalofMembraneScience,2003,216(1-2):257-268.[]LIUY,WANGR,CHUNGTS.Chemicalcross-linkingmodificationofpolyimidemembranesforgasseparation[J].JournalofMembraneScience,2001,189(2):231-239.[]CHUNGTS,SHAOL,TINPS.SurfaceModificationofPolyimideMembranesbyDiaminesforH2andCO2Separation[J].MacromolecularRapidCommunication,2006,27(13):998-1003.图1-4含羧基聚合物与线性二醇分子的交联机理Fig.1-4Themechanismofchemicalcross-linkingbetweencarboxyl-containingpolymersandlineardihydroxymoleculesKoros课题组使用乙二醇作为交联剂对6FDA-mPD/DABA聚酰亚胺进行交联[[]STAUDT-BICKELC,KOROSWJ.ImprovementofCO2/CH4separationcharacteristicsofpolyimidesbychemicalcrosslinking[J].JournalofMembraneScience,1999,155(1):145-154.]，由于DABA含有强极性的羧酸基团可以与乙二醇发生化学反应，降低聚合物链的迁移率，交联聚合物膜具有良好的抗塑化性能。该组还通过丙二醇作为交联剂处理中空纤维气体分离膜[[][]STAUDT-BICKELC,KOROSWJ.ImprovementofCO2/CH4separationcharacteristicsofpolyimidesbychemicalcrosslinking[J].JournalofMembraneScience,1999,155(1):145-154.[]KRATOCHVILAM,KOROSWJ.EffectsofSupercriticalCO2ConditioningonCross-LinkedPolyimideMembrane[J].Macromolecules,2010,43(10):4679-4687.[]MAC,KOROSWJ.EffectsofhydrocarbonandwaterimpuritiesonCO2/CH4separationperformanceofester-crosslinkedhollowfibermembranes[J].JournalofMembraneScience,2014,451:1-9.[]DUN,CINMD,PINNAUI,etal.Azide-basedcross-linkingofpolymersofintrinsicmicroporosity(PIMs)forcondensablegasseparation[J].Macromolecularrapidcommunications,2011,32(8):631-636.UV辐射交联UV交联是指通过紫外线照射使聚合物链在某些化学键处出现了裂解产生自由基，在光化学反应下发生重排交联的反应。Kita等发现能够通过改变照射时间来调节膜材料的气体渗透性能[[]KITAH,INADAT,TANAKAK,etal.Effectofphotocrosslinkingonpermeabilityandpermselectivityofgasesthroughbenzophenone-containingpolyimide[J].JournalofMembraneScience,1994,87(1):139-147.]，膜的选择性随着照射时间的增加而不断升高，但是由于链间距的减小会使膜的渗透性不断降低。Paul等通过UV照射对聚芳酯进行处理[[]MCCAIGMS,PAULDR.EffectofUVcrosslinkingandphysicalagingonthegaspermeabilityofthinglassypolyarylatefilms[J].Polymer,1999,40(26):7209-7225.[]KITAH,INADAT,TANAKAK,etal.Effectofphotocrosslinkingonpermeabilityandpermselectivityofgasesthroughbenzophenone-containingpolyimide[J].JournalofMembraneScience,1994,87(1):139-147.[]MCCAIGMS,PAULDR.EffectofUVcrosslinkingandphysicalagingonthegaspermeabilityofthinglassypolyarylatefilms[J].Polymer,1999,40(26):7209-7225.[]ROSUL,SAVAI,ROSUD.Modificationofthesurfacepropertiesofapolyimidefilmduringirradiationwithpolychromiclight[J].AppliedSurfaceScience,2011,257(15):6996-7002.[]LIFY,XIAOYC,ONGYK,etal.UV-rearrangedPIM-1Polymericmembraneforadvancedhydrogenpurificationandproduction[J].AdvancedEnergyMaterials,2012,2(12):1-11.图1-5PIM-1膜光化学反应的机理Fig.1-5MechanismofthephotochemicalreactionofPIM-1membranes热诱导交联热诱导交联是指通过高温驱使聚合物链上的一些化学键出现了断裂产生了自由基，自由基之间形成交联结构[[]CHUAML,XIAOYC,CHUNGTS.Effectsofthermallylabilesaccharideunitsonthegasseparationperformanceofhighlypermeablepolyimidemembranes[J].JournalofMembraneScience,2012,415:375-382.]。通常交联改性的聚合膜有着良好的选择性、耐化学性和耐塑化性[[]ZHANGCL,LIP,CAOB.DecarboxylationcrosslinkingofpolyimideswithhighCO2/CH4separationperformanceandplasticizationresistance[J].JournalofMembraneScience,2017,528:206-216.,[][]CHUAML,XIAOYC,CHUNGTS.Effectsofthermallylabilesaccharideunitsonthegasseparationperformanceofhighlypermeablepolyimidemembranes[J].JournalofMembraneScience,2012,415:375-382.[]ZHANGCL,LIP,CAOB.DecarboxylationcrosslinkingofpolyimideswithhighCO2/CH4separationperformanceandplasticizationresistance[J].JournalofMembraneScience,2017,528:206-216.[]KRATOCHVILAM,KOROSWJ.Decarboxylation-InducedCross-LinkingofaPolyimideforEnhancedCO2PlasticizationResistance[J].Macromolecules,2016,41(21):7920-7927.图1-6从聚酰亚胺、环糊精接枝的聚酰亚胺到热交联的环糊精接枝的聚酰亚胺的演变过程。Fig.1-6TheevolutionschemefrompolyimideandcyclodextringraftedpolyimidetothermallycrosslinkedcyclodextringraftedpolyimideChung等将环糊精接枝在带有羧基侧基的高刚性聚酰亚胺上[[]XIAOY,CHUNGTS.Graftingthermallylabilemoleculesoncross-linkablepolyimidetodesignmembranematerialsfornaturalgaspurificationandCO2capture[J].Energy&EnvironmentalScience,2011,4(1):201.][]XIAOY,CHUNGTS.Graftingthermallylabilemoleculesoncross-linkablepolyimidetodesignmembranematerialsfornaturalgaspurificationandCO2capture[J].Energy&EnvironmentalScience,2011,4(1):201.[]ANH,LEEAS,KAMMAKAKAMI,etal.Bromination/Debromination-InducedThermalCrosslinkingof6FDA-DureneforAggressiveGasSeparations[J].JournalofMembraneScience,2017,545:358-366.在热诱导处理聚合物膜的过程中，当热处理温度高于Tg时，容易导致基于这种材料的中空纤维膜的孔结构和过渡层塌陷。为了解决这一难题，最有效的方法是增加聚合物的Tg。Koros等合成了6FDA-DAM:DABA聚合物（Tg=387℃）[[]QIUW,CHENCC,XUL,etal.Sub-TgCross-LinkingofaPolyimideMembraneforEnhancedCO2PlasticizationResistanceforNaturalGasSeparation[J].Macromolecules,2011,44(15):6046-6056.]，这种聚合物可以在330℃时完全交联，交联机理如图1-7(a)所示。交联后形成的聚合物膜的选择性几乎不变，渗透性和抗塑化性都得到了很大的提升。另外退火时间和温度都可以通过影响聚合物膜的交联程度而间接影响选择性。Tian等制备了玻璃化转变温度为450℃的侧链含羧基的三蝶烯基聚酰亚胺[[]QIUW,CHENCC,XUL,etal.Sub-TgCross-LinkingofaPolyimideMembraneforEnhancedCO2PlasticizationResistanceforNaturalGasSeparation[J].Macromolecules,2011,44(15):6046-6056.[]TIANZK,CAOB,LIP.Effectsofsub-Tgcross-linkingoftriptycene-basedpolyimidesongaspermeation,plasticizationresistanceandphysicalagingproperties[J].JournalofMembraneScience,2018,560:87-96.图1-7两种热诱导交联机理：（a）脱羧交联（b）热氧化交联Fig.1-7Twothermally-inducedcross-linkingmechanisms:(a)Decarboxylationcrosslinking(b)ThermaloxidativecrosslinkingZhang等合成了两种含内酯环侧基的6FDA-MPP与6FDA-PP聚酰亚胺[[]ZHANGC,CAOB,LIP.Thermaloxidativecrosslinkingofphenolphthalein-basedcardopolyimideswithenhancedgaspermeabilityandselectivity[J].J