简介：Cobaltandnickelcomplexes(1a-1dand2a-2d,respectively)supportedby2-imidate-pyridineligandsweresynthesizedandusedfor1,3-butadienepolymerization.ThecomplexeswerecharacterizedbyIRandelementanalysis,andcomplex1awasfurthercharacterizedbysingle-crystalX-raydiffraction.Thesolidstatestructureofcomplex1adisplayedadistortedtetrahedralgeometry.Uponactivationwithethylaluminumsesquichloride(EASC),allthecomplexesshowedhighactivitiestoward1,3-butadienepolymerization.Thecobaltcomplexesproducedpolymerswithhighcis-1,4contentsandhighmolecularweights,whilethenickelcomplexesdisplayedlowcis-1,4selectivityandtheresultingpolymershadlowmolecularweights.Thecatalyticactivitiesofthecomplexeshighlydependedontheligandstructure.Withtheincrementofpolymerizationtemperature,thecis-1,4contentandthemolecularweightoftheresultingpolymerdecreased.

简介：Inordertoimprovetheflexibilityofpoly(propylenecarbonate)(PPC),poly(1,2-propylenesuccinate)(PPSu)wasusedtoplasticizePPCinabatchmixer.TheeffectsofPPSuonthemiscibility,thermalstability,mechanicalandrheologicalpropertiesoftheblendswereinvestigated.PPCwaspartiallymisciblewithPPSu.ItwasdemonstratedthatPPSudecreasedtheglasstransitiontemperatureandmeltviscosityofPPC,asshownintheDSCandrheologicalcurves.WiththeincreaseinPPSucontent,thePPC/PPSublendsshoweddecreasedtensilestrength,however,theelongationatbreakwasincreasedto1100%forthe70/30PPC/PPSublend.TheintroductionofPPSuprovidedanefficientandnovelplasticizationmethodtoextendtheapplicationareaofPPC.

简介：Fivenewopticallyactivepolyamides(PAs)6a-6ewerepreparedbydirectpolycondensationreactionof2-(1,3-isoindolinedione-2-yl)-glutaricacid4asanewchiraldiacidwithvariousaromaticdiamines5a-5einamediumconsistingoftriphenylphosphite(TPP),calciumchloride,pyridine(Py)andN-methyl-2-pyrrolidone(NMP).Thepolycondensationreactionproducedaseriesofpolyamids6a-6einquantitativeyieldswithinherentviscositiesof0.26-0.39dL/g.Theresultingpolymerswerefullycharacterizedbymeansof~1H-NMR,FT-IRspectroscopy,elementalanalysis,inherentviscosityandspecificrotation.Thermalpropertiesofthesepolymerswereinvestigatedusingthermalgravimetricanalysis(TGA)anddifferentialthermalgravimetry(DTG).PhthalimideringsasabulkypendentgroupinthepolymerchainsdisturbtheinterchainandintrachaininteractionsandmakethesePAsreadilysolubleinpolar,aproticsolventssuchasN,N-dimethylacetamide(DMAc),N,N-dimethylformamide(DMF),dimethylsulfoxide(DMSO),N-methyl-2-pyrrolidone(NMP)andsulfuricacid.

简介：Usingsupportedmulti-componentzincdicarboxylatecatalyst,poly(1,2-propylenecarbonate-co-1,2-cyclohexylenecarbonate)(PPCHC)wassuccessfullysynthesizedfromcarbondioxide(CO_2)withpropyleneoxide(PO)andcyclohexeneoxide(CHO).Theconversionofepoxidesdramaticallyincreasedupto89.7%(yield:384.2gofpolymerpergofZn)withincreasingreactiontemperaturefrom60℃to80℃.Theoptimizedreactiontemperatureis80℃.Thechemicalstructure,themolecularweight,aswellasthermalandmechanicalpropertiesoftheresultingterpolymerswereinvestigatedextensively.WhenCHOfeedcontent(mol%)islowerthan10%,thePPCHCterpolymershavenumberaveragemolecularweight(M_n)rangingfrom102×10~3to202×10~3andmolecularweightdistribution(MWD)valuesrangingfrom2.8to3.5.Incontrasttopoly(propylenecarbonate)(PPC),theintroductionofsmallamountofCHOleadstoincreaseintheglasstransitiontemperaturefrom38.0℃to42.6℃.Similarly,themechanicalstrengthofthesynthesizedterpolymerisgreatlyenhancedduetotheincorporationofCHO.TheseimprovementsinmechanicalandthermalpropertiesareofimportanceforthepracticalapplicationofPPC.