简介：WiththedecreaseofpHvaluefrom8.45to–1.0,theUV-Visabsorptionandfluorescentspectraof1,2-bis(4-pyridyl)ethylene(BPE)tookonthesamechangingtrendatfourdifferentsuccessivepHstages:8.45―7.20,7.20―5.62,5.62―2.60,and2.60―-1.0,namely,nochange,decrease,increase,anddecreaseagain.Amongthese,inarangeof7.20―5.62,thefluorescencewavelengthblueshiftedfrom418to359nm,buttheUV-Visabsorptionwavelength,incontrast,redshiftedfrom285to298nm.ThefluorescenceintensityofBPEhadadropeventoquenchuponadeclineinthepHvaluefrom2.60to–1.0probablyowingtoitscation-πinteractiontoreducetheπelectronclouddensityofBPE.Twodissociationconstants,pKa1(4.30±0.01)andpKa2(5.65±0.04),wereobtainedbasedonfluorescencedata.ThechangesoffluorescencespectraindicatethatBPEhas'off-on-off'switchbehavior.ThefluorescentspectraofBPEwerenearlyindependentonthepresenceofα-andβ-cyclodextrins.

简介：Agreenprocessfortheoxygen-freeconversionofmethanetohigh-concentrationethyleneandhydrogeninaplasina-followed-by-catalyst(PFC)reactorispresented.Withoutanycatalystsandwithpuremethaneusedasthefeedgas,astablekilohertzsparkdischargeleadstoanacetyleneyieldof64.1%,ethyleneyieldof2.5%andhydrogenyieldof59.0%with80.0%ofmethaneconversionatamethaneflowrateof50cm~3/minandaspecificinputenergyof38.4kJ/L.Intheeffluentgasfromastablekilohertzsparkdischargereactor,theconcentrationsofacetylene,ethyleneandhydrogenwere18.1%,0.7%and66.9%,respectively.WhencatalystsPd-Ag/Si02wereemployedinthesecondstagewithdischargeconditionssameasinthecaseofplasmaalone,thePFCreactorprovidesanethyleneyieldof52.1%andhydrogenyieldof43.4%.TheconcentrationsofethyleneandhydrogenintheeffluentgasfromthePFCreactorwerefoundtobeashighas17.1%and62.6%,respectively.Moreover,noacetylenewasdetectedintheeffluentgas.Thismeansthatahighconcentrationofethyleneandoxygen-freehydrogencanbeco-produceddirectlyfrommethaneinthePFCreactor.

简介：HighlyactiveandselectiveCu/SiO2catalystsforhydrogenationofdimethyloxalate(DMO)toethyleneglycol(EG)weresuccessfullypreparedbymeansofaconvenientone-potsyntheticmethodwithtetraethoxysilane(TEOS)asthesourceofsilica.XRD,H2-TPR,SEM,TEM,XRFandN2physisorptionmeasurementswereperformedtocharacterizethetextureandstructureofCu/SiO2catalystswithdifferentcopperloadings.TheactivecomponentswerehighlydispersedonSiO2supports.Furthermore,thecoexistenceofCu0andCu+contributedalottotheexcellentperformanceofCu-TEOScatalysts.TheDMOconversionreached100%andtheEGselectivityreached95%at498Kand2MPawithahighliquidhourlyspacevelocityoverthe27-Cu-TEOScatalystwithanactualcopperloadingof19.0%(massfraction).

简介：TheStateDevelopmentandReformCommissionhasrecentlyapprovedtheconstructionofa1.0Mt/aclassethyleneunitatZhenhaiRefiningandChemicalCompany.Thisprojectwillcover12unitsincludinga1.0Mt/aethyleneplant,a500kt/aethyleneglycolunit,a450kt/aPEunit,andotherunitswithtotalinvestmentamountingtoaround22.38billionRMB.

简介：Lamellarcrystalsofdiblock,triblockandfour-armpoly(ethyleneglycol)-b-poly(ε-caprolactone)(PEG-b-PCL)crystalline-crystallinecopolymersweresuccessfullyobtainedfromtheirsolution.Morphologyandstructureoflamellarcrystalsofcrystalline-crystallinecopolymerswereinvestigatedusingtapping-modeatomicforcemicroscopy(AFM)andselectedareaelectrondiffraction(SAED).Allofthesesamplesshowedthetruncated-lozengemultilayerbasalshapeswithcentralscrewdislocationorcentralstack,whichwereallobtainedsimultaneouslyfromtheoilbath.ThediffractionpatternofPEGblocklamellarcrystalisattributedtothe(120)diffractingplanesandthepatternofPCLblocklamellarcrystalisattributedtothe(110)diffractingplanesand(200)diffractingplanesaccordingtotheSAEDresults.Four(110)crystalgrowthplanesandtwo(200)crystalgrowthplanesarediscoveredforthePCLblocks,butthe(120)crystalgrowthplanesofPEGblocksarehidedinthefigureofAFM.Thecrystallinestructureofthefour-armcopolymers(FA)ismoredisorderandconfusedthanthatofthediblock(DI)copolymerandthestriatedfoldsurfacestructuresoflamellarcrystalsoffour-armcopolymers(FA)aresmootherthantheseoflinearanalogues,owingtotheconfusedcrystallizationofblockscausedbythemutualrestrictionofblocksandthehindranceofthedendriticcores.Inaddition,theaspectratioofFAisgreaterthanthatoftheothers.Itishypothesizedthattherearetworeasonsforthechangeofaspectratios.First,the(200)diffractingplanesofPCLcrystalsgrewslowlycomparedtotheir(110)diffractingplanesbecauseofdifferenceintheenergybarrier.Secondly,edgedislocationsonthe(200)diffractingplanesarealsoresponsibleforthevariationoftheaspectratio.Consequently,thecrystallinedefectsareaugmentedbythecompetingblockscrystallizedsimultaneouslyandthehindranceofthedendriticcores.

简介：

简介：Anovelclassofsegmentedcopolymers,dimethyldiphenylpolysiloxane/poly(oxytetramethylene)-polyurea(PSPEU),wassynthesizedfromα,ω-bis(γ-aminopropyl)dimethyldiphenylpolysiloxane(APMPS),whichwaspreparedbymeansofbasicring-openingcopolymerizationofoctamethylcyclotetrasiloxane,hexaphenylcyclotrisiloxaneand1,3-bis(γ-aminopropyl)tetramethyldisiloxane.TherelationshipsbetweenthediphenylsiloxycontentsandthepropertiesofAPMPS,includingrefractiveindex,glasstransitiontemperature,solubilityparameteraswellasthermalstability,wereinvestigated;meanwhile,thethermalstability,dynamicmechanicalproperties,mechanicalproperiesaswellastheantithrombogenicityinvitroofthePSPEUwerealsorevealed.

简介：Thecopolymerizationsofethylenewith10-undecen-1-olhavebeeninvestigatedusingvanadiumprecatalysts,bis(imino)pyrrolylvanadium(III)complexes1-3,2,5-C4H2N(CH=NR)2VCl2(THF)2[R=C6H5(1),2,6-iPr2C6H3(2),C6F5(3)],andtheiminopyrrolylandβ-diketiminateonesforcomparison.Thepolarmonomerwaspretreatedbydiethylaluminiumchloride(presentalsoasthecocatalyst)beforethecopolymerization.ThemonomerreactivityratioswereevaluatedusingtheFineman-Rossmethod.Theligandstructureconsiderablyinfluencedthecatalyticactivityandtolerancetowardsthepolarmonomer,thepolarmonomerincorporationandthemolecularweightsoftheresultantcopolymers.Thebis(imino)pyrrolylvanadiumcomplexesexhibitedpromisingcatalyticperformanceforthecopolymerization,andahighcatalyticactivityupto3.84kg/mmolv·hwithahighcomonomerincorporationof14.0mol%wasachievedbycomplex3undermildconditions.

简介：One-stepreactioncompatibilizedmicrofibrillarreinforcediPP/PETblends(CMRB)weresuccessfullypreparedthrougha'slitextrusion-hotstretching-quenching'process.CrystallizationbehaviorandmorphologyofCMRBweresystematicallyinvestigated.Scanningelectronicmicroscopy(SEM)observationsshowedblurryinterfaceofcompatibilizedcommonblend(CCB).ThecrystallizationbehaviorofneatiPP,CCB,microfibrillarreinforcediPP/PETblend(MRB)andCMRBwasinvestigatedbydifferentialscanningcalorimetry(DSC)andpolarizedopticalmicroscopy(POM).TheincreaseofcrystallizationtemperatureandcrystallizationrateduringnonisothermalcrystallizationprocessindicatedbothPETparticlesandmicrofibrilscouldserveasnucleatingagentsandPETmicrofibrilsexhibitedhigherheterogeneousnucleationability,whichwerealsovividlyrevealedbyresultsofPOM.ComparedwithMRBsample,CMRBsamplehaslowercrystallizationtemperatureduetoexistenceofPETmicrofibrilswithsmalleraspectratioandwiderdistribution.Inaddition,sinceinsitucompatibilizertendstostayintheinterphase,itcouldalsohinderthediffusionofiPPmoleculestothesurfaceofPETphase,leadingtodecreaseofcrystallizationrate.Two-dimensionalwide-angleX-raydiffraction(2D-WAXD)waspreformedtocharacterizethecrystallinestructureofthesamplesbyinjectionmolding,anditwasfoundthatwell-developedPETmicrofibrilscontainedinMRBsamplepromotedformationofβ-phaseofiPP.

简介：Thediblockcopolymersintercalatedlayeredsilicatewaspreparedviaameltdispersiontechnique.Thentheeffectofintercalatedhybridasfilleronacrylonitrile-butadiene-styreneresinwascharacterizedbyX-raydiffraction,transmissionelectronmicroscopy,stress-strainmeasurementsinelongation.

简介：Poly(etherurethane)s(PEU),includingPEUI15andPEUH15,werepreparedthroughchain-extensionreactionofpoly(ethyleneglycol)(PEG-1500)usingdiisocyanateasachainextender,includingisophoronediisocyanate(IPDI)andhexamethylenediisocyanate(HDI).ThesePEUswereusedtotoughenpolylactide(PLA)byphysicalandreactiveblending.Thermal,morphological,mechanicalandagingpropertiesoftheblendswereinvestigatedindetail.ThesePEUswerepartiallycompatiblewithPLA.Theelongationatbreakofthereactiveblendsinthepresenceoftriphenylphosphate(TPP)forPLAwithPEUH15orPEUI15wasmuchhigherthanthatofthephysicalblends.Theagingtestwascarriedoutat-20°Cfor50hinordertoacceleratethecrystallizationofPEUs.ThePEUsinthePLA/PEUblendsproducedcrystallizationandformednewphaseseparationwithPLA,resultinginthedeclinedtoughnessofblends.Fortunately,undertheagingcondition,althoughPEUH15inblendscouldalsoformcrystallization,thereactiveblendofPLA/PEUH15/TPP(80/20/2)hadhighertoughnessthantheotherblends.TheelongationatbreakofPLA/PEUH15/TPP(80/20/2)droppedto287%fortheagingblendfrom350%fortheoriginalblend.ThetensilestrengthandmodulusofPLA/PEUH15/TPPblenddidnotchangeobviouslybecauseofthecrystallizationofPEUH15.

简介：Inthiswork,theinfluenceofCO2onthestructuralvariationandcatalyticperformanceofNa2WO4/Mn/SiO2foroxidativecouplingofmethanetoethylenewasinvestigated.ThecatalystwaspreparedbyimpregnationmethodandcharacterizedbyXRD,RamanandXPStechniques.AppropriateamountofCO2inthereactantgasesenhancedtheformationofsurfacetetrahedralNa2WO4speciesandpromotedthemigrationofOinMOx,Na,Wfromthecatalystbulktosurface,whichwerefavorableforoxidativecouplingofmethane.WhenthemolarratioofCH4/O2/CO2was3/1/2,enrichedsurfacetetrahedralNa2WO4speciesandhighsurfaceconcentrationofOinMOx,Na,Wweredetected,andthenhighCH4conversionof33.1%andhighC2H4selectivityof56.2%wereobtained.WithfurtherincreaseofCO2inthereagentgases,thecontentofactivesurfacetetrahedralNa2WO4speciesandsurfaceconcentrationofOinMOx,Na,Wdecreased,whilethatofinactivespecies(MnWO4andMn2O3)increaseddramatically,leadingtolowCH4conversionandlowC2H4selectivity.ItcouldbespeculatedthatNa2WO4crystalwastransformedintoMnWO4crystalwithexcessiveCO2addedunderthereactionconditions.PretreatmentofNa2WO4/Mn/SiO2catalystbymoderateamountofCO2beforeOCMalsopromotedtheformationofNa2WO4species.

简介：中文摘要：通过对生产工艺的改进与调整达到对乙烯焦油和天然气最大化的利用，从而达到节约成本提高效能的作用。

简介：缩放Nano的氧化钇粒子基于含水的钇硝酸盐和乙二醇经由非水的sol-gelprocess被综合。到雏晶上的钇离子和锻烧温度的乙二醇的臼齿的比率的效果产品缩放我们再学习。为铵perehlorate(AP)的同样准备的氧化钇的催化表演分解被微分扫描调查热量测定(DSC)。结果显示有在平均雏晶尺寸的不到20nm的缩放nano的立方的氧化钇粒子能在70degC在2h倒流以后被获得，在90degC弄干，形成xerogel，并且由为2hxerogel退火列在后面，并且到AP的缩放nano的氧化钇的增加在温度合并AP的二座小发热的山峰，这310~变化350degC并且400-470degC进AP和增加的一座强壮的发热的山峰从515的明显的分解热到超过1110Jcentre点g~(-1)。发热的山峰减少和明显的分解AP加热的AP分解的温度随数量的增加增加缩放ofnano的氧化钇，也是清楚的。到AP的5%缩放nano的氧化钇的增加减少的事实到由114.6degC的减小的337.7degC的AP发热的山峰的温度，并且从515～1240J中心点g~增加明显的分解热(-1),揭示那缩放nano的氧化钇hows为AP的强壮的催化性质热分解。