熱重排聚合物的研究文獻綜述熱重排（TR）聚合物是含鄰位羥基的PI受到熱誘導(dǎo)的情況下，酰亞胺環(huán)與鄰位羥基發(fā)生重排反應(yīng)轉(zhuǎn)化而來的聚合物,也稱為聚苯并噁唑（PBO）聚合物[[]WOOCKT,BJORGAARDS,TANDEB,etal.Purificationofnaturalgasusingthermallyrearrangedpolybenzoxazoleandpolyimidemembranes-areview:part1[J].MembraneTechnology,2016,9:7-12.,[]WOOCKT,BJORGAARDS,TANDEB,etal.Purificationofnaturalgasusingthermallyrearrangedpolybenzoxazoleandpolyimidemembranes-areview:part2[J].MembraneTechnology,2016,10:7-12.]。聚酰亞胺在發(fā)生熱重排反應(yīng)的過程中會在形成的高剛性聚合物鏈之間產(chǎn)生微孔和沙漏狀雙峰分布的微腔，其中微孔和微腔的尺寸大約分別為3-4?和9-10?[[]HANSH,KWONHJ,KIMKY,etal.TuningmicrocavitiesinthermallyrearrangedpolymermembranesforCO2capture[J].PhysicalChemistryChemicalPhysics,2012,14(13):4365-4373.]。TR聚合物氣體分離膜一般情況下都具有較高的氣體滲透性和良好的氣體選擇性。研究人員對TR聚合物在TR化學(xué)反應(yīng)機理[[]DONGG,LEEYM.Microporouspolymericmembranesinspiredbyadsorbentforgasseparation[J].JournalofMaterialsChemistryA,2017,5:13294-13319.[]WOOCKT,BJORGAARDS,TANDEB,etal.Purificationofnaturalgasusingthermallyrearrangedpolybenzoxazoleandpolyimidemembranes-areview:part1[J].MembraneTechnology,2016,9:7-12.[]WOOCKT,BJORGAARDS,TANDEB,etal.Purificationofnaturalgasusingthermallyrearrangedpolybenzoxazoleandpolyimidemembranes-areview:part2[J].MembraneTechnology,2016,10:7-12.[]HANSH,KWONHJ,KIMKY,etal.TuningmicrocavitiesinthermallyrearrangedpolymermembranesforCO2capture[J].PhysicalChemistryChemicalPhysics,2012,14(13):4365-4373.[]DONGG,LEEYM.Microporouspolymericmembranesinspiredbyadsorbentforgasseparation[J].JournalofMaterialsChemistryA,2017,5:13294-13319.[]LIUW,XIEW.Acetate-FunctionalThermallyRearrangedPolyimidesBasedon2,2-Bis(3-amino-4-hydroxyphenyl)hexafluoropropaneandVariousDianhydridesforGasSeparations[J].Industrial&EngineeringChemistryResearch,2014,53(2):871-879.[]SMITHS,HOURJ,LAUCH,etal.HighlypermeableThermallyRearrangedMixedMatrixMembranes(TR-MMM)[J].JournalofMembraneScience,2019,585:260-270.[]DOYS,SEONGJG,KIMS,etal.Thermallyrearranged(TR)poly(benzoxazole-co-amide)membranesforhydrogenseparationderivedfrom3,3′-dihydroxy-4,4′-diamino-biphenyl(HAB),4,4′-oxydianiline(ODA)andisophthaloylchloride(IPCI)[J].JournalofMembraneScience,2013,446:294-302.[]LIUQ,BORJIGINH,PAULDR,etal.Gaspermeationpropertiesofthermallyrearranged(TR)isomersandtheiraromaticpolyimideprecursors[J].JournalofMembraneScience,2016,518:88-99.[]ZHUANGYB,SEONGJG,LEEWH,etal.MechanicallyTough,ThermallyRearranged(TR)Random/BlockPoly(benzoxazole-co-imide)GasSeparationMembranes[J].Macromolecules,2015,48(15):5286-5299.[]COMESANA-GáNDARAB,CALLEM,JOHJ,etal.Thermallyrearrangedpolybenzoxazolesmembraneswithbiphenylmoieties:Monomerisomericeffect[J].JournalofMembraneScience,2014,450:369-379.[]CALLEM,LEEYM.ThermallyRearranged(TR)Poly(etherbenzoxazole)MembranesforGasSeparation[J].Macromolecules,2011,44(5):1156-1165.Park等在2007年對熱重排反應(yīng)機理做了解釋[[]PARKHB,JUNGCH,LEEYM,etal.Polymerswithcavitiestunedforfastselectivetransportofsmallmoleculesandions[J].Science,2007,318(5848):254-258.]，即含有鄰位官能團（-OH和-SH等）的聚酰亞胺在350-450℃的溫度范圍下發(fā)生分子重排，如圖1-8所示。在發(fā)生反應(yīng)的過程中鏈結(jié)構(gòu)的重排改變膜內(nèi)鏈的堆積方式，主鏈上亞苯基和苯并噁唑環(huán)之間的旋轉(zhuǎn)具有高的扭轉(zhuǎn)能壘。這些高度扭曲的剛性鏈不但可以增加膜內(nèi)微孔的形成數(shù)量，而且還可以防止孔塌陷。Scholes等研究了TR結(jié)構(gòu)的比例對共聚聚酰亞胺的影響[[][]PARKHB,JUNGCH,LEEYM,etal.Polymerswithcavitiestunedforfastselectivetransportofsmallmoleculesandions[J].Science,2007,318(5848):254-258.[]SCHOLESCA,RIBEIROCP,KENTISHSE,etal.Thermalrearrangedpoly(benzoxazole-co-imide)membranesforCO2separation[J].JournalofMembraneScience,2014,450:72-80.圖1-8熱重排反應(yīng)的反應(yīng)機理Fig.1-8Themechanismofthermalrearrangementreaction對于熱重排聚合物，在酰亞胺環(huán)轉(zhuǎn)化為苯并噁唑環(huán)時必須要有一定的轉(zhuǎn)化率才能保證TR聚合物膜擁有較高的氣體滲透性。但是對于聚合物膜而言，較高的結(jié)構(gòu)轉(zhuǎn)化率需要在較高的溫度下實現(xiàn)，而高溫容易導(dǎo)致機械性能和選擇性下降[[]PARKHB,HANSH,JUNGCH,etal.Thermallyrearranged(TR)polymermembranesforCO2separation[J].JournalofMembraneScience,2010,359(1-2):11-24.-[]SANDERSDF,GUOR,SMITHZP,etal.Influenceofpolyimideprecursorsynthesisrouteandortho-positionfunctionalgrouponthermallyrearranged(TR)polymerproperties:Conversionandfreevolume[J].Polymer,2014,55:1636-1647.[]CALLEM,JOHJ,DOHERTYCM,etal.Cross-LinkedThermallyRearrangedPoly(benzoxazole-co-imide)MembranesPreparedfromortho-HydroxycopolyimidesContainingPendantCarboxylGroupsandGasSeparationProperties[J].Macromolecules,2015,48(8):2603-2613.]。Guo等對TR轉(zhuǎn)化率的影響因素進行研究[[]GUOR,SANDERSDF,SMITHZP,etal.Synthesisandcharacterizationofthermallyrearranged(TR)polymers:effectofglasstransitiontemperatureofaromaticpoly(hydroxyimide)precursorsonTRprocessandgaspermeationproperties[J].JournalofMaterialsChemistryA,2013,1(19):6063.]，發(fā)現(xiàn)熱重排的反應(yīng)開始發(fā)生的溫度取決于聚酰亞胺前驅(qū)體的Tg。通過在聚酰亞胺的合成過程中使用雙酚A二酐作為單體降低了PI的T[]PARKHB,HANSH,JUNGCH,etal.Thermallyrearranged(TR)polymermembranesforCO2separation[J].JournalofMembraneScience,2010,359(1-2):11-24.[]SANDERSDF,GUOR,SMITHZP,etal.Influenceofpolyimideprecursorsynthesisrouteandortho-positionfunctionalgrouponthermallyrearranged(TR)polymerproperties:Conversionandfreevolume[J].Polymer,2014,55:1636-1647.[]CALLEM,JOHJ,DOHERTYCM,etal.Cross-LinkedThermallyRearrangedPoly(benzoxazole-co-imide)MembranesPreparedfromortho-HydroxycopolyimidesContainingPendantCarboxylGroupsandGasSeparationProperties[J].Macromolecules,2015,48(8):2603-2613.[]GUOR,SANDERSDF,SMITHZP,etal.Synthesisandcharacterizationofthermallyrearranged(TR)polymers:effectofglasstransitiontemperatureofaromaticpoly(hydroxyimide)precursorsonTRprocessandgaspermeationproperties[J].JournalofMaterialsChemistryA,2013,1(19):6063.[]HANSH,MISDANN,KIMS,etal.ThermallyRearranged(TR)Polybenzoxazole:EffectsofDiverseimidizationRoutesonPhysicalPropertiesandGasTransportBehaviors[J].Macromolecules,2010,43(18):7657-7667.圖1-9TB基聚苯并噁唑的形成及其分子模型（灰球為C原子，藍球為N原子，黃球為F原子，紅球為O原子）Fig.1-9ThermalrearrangementreactionleadingtoaTB-basedpolybenzoxazoleandmolecularmodelof6FDA-TR-TB:Cgray,Nblue,Fyellow,Ored另外TR氣體分離膜在分離一些動力學(xué)直徑相差較小的氣體對時表現(xiàn)出了顯著的優(yōu)勢。Meckler等合成了一種含Tr?ger’sBase（TB）結(jié)構(gòu)的鄰羥基二胺[[]MECKLERSM,BACHMANJE,ROBERTSONBP,etal.ThermallyRearrangedPolymerMembranesContainingTroger’sBaseUnitswithExceptionalPerformanceforAirSeparations[J].AngewandteChemie-InternationalEdition,2018,57:4912-4916.]，將TB結(jié)構(gòu)引入到TR聚合物中。TB結(jié)構(gòu)作為TR聚合物骨架上的扭曲位點（如圖1-9所示），與傳統(tǒng)的含有大體積螺環(huán)中心的TR聚合物不同，TB結(jié)構(gòu)的二面角擾動會產(chǎn)生更高的能量損失。熱重排反應(yīng)發(fā)生之后內(nèi)部微孔網(wǎng)絡(luò)出現(xiàn)了顯著的重構(gòu)，導(dǎo)致聚合物膜具有非常優(yōu)異的氧氣滲透性和O2/N2選擇性，超過了2015年上限[NOTEREF_Ref72939169\h41]。Hu等合成一種高剛性的鄰羥基二胺TMBDA[[]HUXF,LEEWH,ZHAOJY,etal.Thermallyrearrangedpolymermembranescontaininghighlyrigidbiphenylortho-hydroxyldiamineforhydrogenseparation[J].JournalofMembraneScience,2020,604:1-12.]，與6FDA和PMDA反應(yīng)生成了具有扭曲聯(lián)苯結(jié)構(gòu)的聚酰亞胺前驅(qū)體。通過熱重排反應(yīng)得到的聚苯并噁唑聚合物膜具有三個不同的鏈間距，其中最小的鏈間距位于H2分子和CH4分子二者動力學(xué)直徑之間。因此，該TR聚合物在氫氣分離方面表現(xiàn)出色，其中425℃處理的TR聚合物的H2滲透性達到了325barrer，H2/CH4和H2/N2[]MECKLERSM,BACHMANJE,ROBERTSONBP,etal.ThermallyRearrangedPolymerMembranesContainingTroger’sBaseUnitswithExceptionalPerformanceforAirSeparations[J].AngewandteChemie-InternationalEdition,2018,57:4912-4916.[]HUXF,LEEWH,ZHAOJY,etal.Thermallyrearrangedpolymermembranescontaininghighlyrigidbiphenylortho-hydroxyldiamineforhydrogenseparation[J].JournalofMembraneScience,2020,604:1-12.相比于流延法制得的平板膜，中空纖維膜大約占工業(yè)應(yīng)用中氣體分離膜市場的80%[[]LID,WANGR,CHUNGTS.Fabricationoflab-scalehollowfibermembranemoduleswithhighpackingdensity[J].Separation&PurificationTechnology,2004,40(1):15-30.]，這是由于這一類型的膜的表面積與體積之比大約在41000m2/m3左右，比卷式膜組件還要高出兩個數(shù)量級[[]BERNARDOP,DRIOLIE,GOLEMMEG.MembraneGasSeparation:AReview/StateoftheArt[J].Industrial&En