Abstract
Polypropylene oxide (PPO) and poly(9-(2,3-epoxypropyl) carbazole) (PEPK) di-block copolymers are prepared in one pot via sequential monomer addition by using i-PrONa/i-Bu3Al as an anionic catalytic system. An almost 100% monomer conversion is obtained, and the length of each block is controlled through the monomer/catalyst ratio used. Copolymer molecular weights are quite close to theoretical values calculated assuming the formation of one polymer chain per catalyst; therefore, it is hypothesized that the polymerization reaction proceeds with a living character. The synthesis appears to be particularly efficient and versatile. The calorimetric properties of copolymers obtained in this work are remarkable, since they show two distinct Tg values, corresponding to the PPO and PEPK blocks. The optical measurements of di-block copolymers show more analogous features than those of PEPK homopolymer. Copolymer solution emission spectra just exhibit isolated carbazole fluorescence, whereas in the solid state, film spectra show excimer fluorescence.
Highlights
The synthesis of polymers with pendant carbazolyl groups has attracted great academic and industrial interest thanks to the unique spectroscopic properties that they exhibit [1,2,3,4,5,6,7]
Toluene was refluxed over sodium for 48 h and distilled before use, propylene oxide was purified on CaH2 and distilled before use, and other reagents were used without further purification. i-PrONa was synthesized by reaction of i-PrOH with sodium dispersed in toluene
polypropylene oxide (PPO)-b-PEPK copolymers have been synthesized by using i-PrONa/i-Bu3Al as an initiating system in one pot via sequential monomer addition
Summary
The synthesis of polymers with pendant carbazolyl groups has attracted great academic and industrial interest thanks to the unique spectroscopic properties that they exhibit [1,2,3,4,5,6,7]. Block copolymers presenting polymeric blocks containing pendant carbazolyl groups have gained much attention because of their potential ability to form ordered structures through self-assembly processes, which makes them promising materials for applications in optoelectronics. They could be employed as light-emitting or organic photo-refractive materials. By tuning the chemical nature and length of each block, block copolymers with peculiar chemical, physical and optoelectronic properties can be suitably obtained To this aim, controlled polymerization techniques, i.e., controlled radical or living anionic methods, have to be employed. As a matter of fact, Deffieux et al reported a controlled anionic polymerization of btaaiatbvnhh-nncyePeetrdiseooEuyuarnrdPsA,iisemitiiKhwnctassiopgbcieatcrnaloeoetiwmPitiiacPoalir--dpnotothtsPpfPOPevibtaaiatviiaeoibanahhmltarapxOtrnnctayeteahltOtyrhOeepbttyllrdioaalvse-aeeiutoooueyyetbmNesuiravhNcerrhne[nrwd-rtssdA,itirsa3tuPeosaiemeitieaiihyhmwblan4t-ctan/sEssrftrutciaeio]ashapg,baioscfp-Pieaate.eniosrannnBhwalioexamnlTKrsuetsiegrmcacliriduoi-reetthodoeitctsuPpwepeacvirti3i,ttainbead-amAlrtipaxioolataDottPeasctOitbyinrpotptplllcconaleratseoreuieiuyldoebeeoNempiprOevlairfbcmlne[adrnsnsdlfyslea3oasvtyoesaiiNleeiidamrebloak4elenxa/atmfartiussciui[iir]fnadaahvpsltnnfp-oati3ae.teiure/slaxsBtitiezet4nlTirsoomysrteruaceioqcdirauehe]instmnhl-dtusiwmrg.uptacvtBap3,miieoasiesAlsiuTltioteDoaaocurea,sxirftieboetniaellchleanenplertpt3erna.yeuanoebcelogteAiaotfreclacgnmisiasdeatnsrfenssulroacaeottitullsaleydepmirhekhhegldnllabarrmsalsamwkauiroaeyevrcscutnssotabtisotorlxsrioeeeezeceetyiipfoolatnuxwinqnnednrgahoordreensmnlnoivmerutittdytctrdatdizeorlaiiasreem[katiiyeliaoaai,eoxails3ftinkttamdgstnllmanleoispttllP4aas.aeissPoueciogtte,]toreloauoaPlniesnpoPbnii.iienxwrnafcnatontrmtOanserOgTqmpirhphhgtiglednr,mcahtzitkuhsoeeieranrptmahebwtamnsitoooteoirroeceuctgr.aypttrfltigxrwnahoflghiaeiooamieIrstsleotoialslthtteeyecordhtdtfabnlayenelpaeem[kdhieoynkretlPlr3gsatsamtlnrorhemekioysohplPt4aramoyPaewtecceerolf,o]ntoaaPvf,lpOepoankom.yitasxooswlliPnoirsOloonrgwyTosed-irubrliPtcdnO,edblshetztmnmathepoeymrwpPmh-ehneari[idtceooPmmfrcsepc.3aOtastrgairheofulihEiPrin4Irtrwlen1puotabepailtiieenoe]PhEmufacz0onrgnoilsp.adieosdnnkhK.ra0PemPnsdlrrercTorfeyyeoet%IaKmeoPetnhewrpitlhrtcmolfhnooavct,pOrata,lvrPoieahfoeiianciPrimissoilwoenneoarpsPd-ynouerntoOvmreblrwslonigatoOhenymkinycn-pefhtiplrfzidlPdoihamvooeyslpcgte-yrcaeicPiuisrbaEmeeerolnhvrwmn1pltreeastOt-pdrdnoeiPpuih0hPierg,lobossinesoed,sduKe0-msais1hlEinperecrgPuaolfryneem%tt0eyosnhwrPrttanarrntcome0PoieccwmatolOivrKowelfdeiians%chtmtePtiiennsephhresPtnnoinNeeuaairOnrcheignteooarnrOsrrcinymothapalgezletl-ft-vohvpeilgcpyiamecninenaeefrhcvmoltrrtoirdrgovaiaaihnoilyospinend,syeri-aimglnnekergPaoirmcetvlsrsatltnaertoPtpoichitoebOawlionfhhstePeeiarldnhPtgnNeeesasaritOh,taOsrhaae-t-t a low-toxipchbao-nPtodEcPsooKnfdtcuomcpatoitvleyermipaerlorsspueacrrhteiaetsr.uPFlPyuOrinthwtreiirgtmhuoitnhrgeo,smtehaeotfePrPiaEOlPs-bKb-,PecwEaPhuKiscehctohspheooylwycmosmererbsmincaoeruktlhadebblpeeroalpseortaibelseof toafolorwm-otorxdiecreadndstsroufcttumraestetrhiarol usugchhsealsf-PaPssOemwbitlhy pthroosceesosfesP.ETPhKe,mwihcricohstrsuhcotwurser,epmhayrskicaob-le chemical and optical properties of the obtained di-block copolymers are reported in the paper
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