Cov tshuaj sib xyaw ntawm poly-L-lactic acid thiab ethyl cellulose hauv chloroform thiab cov tshuaj sib xyaw ntawm PLLA thiab methyl cellulose hauv trifluoroacetic acid tau npaj, thiab PLLA / cellulose ether blend tau npaj los ntawm casting;Cov kev sib xyaw tau txais yog cov yam ntxwv ntawm nplooj hloov pauv infrared spectroscopy (FT-IR), qhov sib txawv scanning calorimetry (DSC) thiab X-ray diffraction (XRD).Muaj hydrogen daim ntawv cog lus ntawm PLLA thiab cellulose ether, thiab ob qho tib si yog ib feem sib xws.Nrog rau qhov nce ntawm cellulose ether cov ntsiab lus nyob rau hauv qhov sib tov, lub melting point, crystallinity thiab siv lead ua kev ncaj ncees ntawm kev sib tov yuav txo.Thaum MC cov ntsiab lus siab dua 30%, yuav luag amorphous blends tau.Yog li, cellulose ether tuaj yeem siv los hloov kho poly-L-lactic acid los npaj cov khoom siv polymer degradable nrog cov khoom sib txawv.
Hot Tags: poly-L-lactic acid, ethyl cellulose,methyl cellulose, blending, cellulose ether
Kev txhim kho thiab siv cov khoom siv hluav taws xob ntuj thiab cov khoom siv hluav taws xob tsis zoo yuav pab daws cov teeb meem ib puag ncig thiab cov peev txheej cuam tshuam los ntawm tib neeg.Nyob rau hauv xyoo tas los no, kev tshawb fawb txog kev sib txuas ntawm biodegradable polymer cov ntaub ntawv siv cov khoom siv txuas ntxiv dua li cov khoom siv polymer tau nyiam ntau yam.Polylactic acid yog ib qho tseem ceeb degradable aliphatic polyesters.Lactic acid tuaj yeem tsim los ntawm fermentation ntawm cov qoob loo (xws li pob kws, qos yaj ywm, sucrose, thiab lwm yam), thiab tuaj yeem decomposed los ntawm cov kab mob.Nws yog ib qho khoom siv txuas ntxiv.Polylactic acid yog npaj los ntawm lactic acid los ntawm ncaj qha polycondensation los yog lub nplhaib-qhib polymerization.Cov khoom kawg ntawm nws cov degradation yog lactic acid, uas yuav tsis ua phem rau ib puag ncig.PIA muaj cov khoom siv zoo heev, kev ua tau zoo, biodegradability thiab biocompatibility.Yog li ntawd, PLA tsis tsuas yog muaj ntau yam kev siv hauv kev lag luam biomedical engineering, tab sis kuj tseem muaj kev lag luam loj loj hauv kev lag luam txheej, plastics, thiab textiles.
Tus nqi siab ntawm poly-L-lactic acid thiab nws cov kev ua haujlwm tsis zoo xws li hydrophobicity thiab brittleness txwv nws daim ntawv thov ntau yam.Txhawm rau txo nws cov nqi thiab txhim kho kev ua haujlwm ntawm PLLA, kev npaj, kev sib raug zoo, morphology, biodegradability, mechanical zog, hydrophilic / hydrophobic tshuav nyiaj li cas thiab daim ntawv thov teb ntawm polylactic acid copolymers thiab blends tau kawm tob.Ntawm lawv, PLLA tsim ib qho kev sib xyaw ua ke nrog poly DL-lactic acid, polyethylene oxide, polyvinyl acetate, polyethylene glycol, thiab lwm yam Cellulose yog lub ntuj polymer compound tsim los ntawm condensation ntawm β-glucose, thiab yog ib qho ntawm cov khoom siv txuas ntxiv dua qub. nyob rau hauv qhov.Cellulose derivatives yog cov khoom siv ntuj qub tshaj plaws uas tsim los ntawm tib neeg, qhov tseem ceeb tshaj plaws yog cellulose ethers thiab cellulose esters.M.Nagata et al.tau kawm PLLA / cellulose blend system thiab pom tias ob lub ntsiab lus tsis sib xws, tab sis cov crystallization thiab degradation ntawm PLLA tau cuam tshuam zoo heev los ntawm cov khoom siv cellulose.N.Ogata thiab al tau kawm txog kev ua haujlwm thiab cov qauv ntawm PLLA thiab cellulose acetate blend system.Cov Japanese patent kuj tau kawm txog biodegradability ntawm PLLA thiab nitrocellulose blends.Y.Teramoto thiab al kawm txog kev npaj, thermal thiab mechanical zog ntawm PLLA thiab cellulose diacetate graft copolymer.Txog tam sim no, muaj kev tshawb fawb tsawg heev ntawm kev sib xyaw ntawm polylactic acid thiab cellulose ether.
Nyob rau hauv xyoo tas los no, peb pab pawg tau koom nrog hauv kev tshawb fawb ntawm cov khoom siv hluav taws xob ncaj qha thiab sib xyaw hloov pauv ntawm polylactic acid thiab lwm yam polymers.Txhawm rau muab cov khoom zoo tshaj plaws ntawm polylactic acid nrog tus nqi qis ntawm cellulose thiab nws cov derivatives los npaj cov ntaub ntawv biodegradable polymer, peb xaiv cellulose (ether) raws li cov kev hloov kho rau kev hloov kho.Ethyl cellulose thiab methyl cellulose yog ob qho tseem ceeb cellulose ethers.Ethyl cellulose yog cov dej-insoluble uas tsis yog-ionic cellulose alkyl ether, uas tuaj yeem siv los ua cov ntaub ntawv kho mob, plastics, adhesives thiab textile finishing agents.Methyl cellulose yog dej-soluble, muaj zoo wettability, cohesiveness, dej tuav thiab film-forming zog, thiab yog dav siv nyob rau hauv lub teb ntawm lub tsev cov ntaub ntawv, coatings, tshuaj pleev ib ce, tshuaj thiab papermaking.Ntawm no, PLLA / EC thiab PLLA / MC blends tau npaj los ntawm kev daws cov txheej txheem casting, thiab kev sib raug zoo, thermal zog thiab crystallization zog ntawm PLLA / cellulose ether blends tau tham.
1. Kev sim ib feem
1.1 Cov khoom siv raw
Ethyl cellulose (AR, Tianjin Huazhen Tshwj Xeeb Chemical Reagent Factory);methyl cellulose (MC450), sodium dihydrogen phosphate, disodium hydrogen phosphate, ethyl acetate, stannous isooctanoate, chloroform (cov saum toj no yog tag nrho cov khoom ntawm Shanghai Chemical Reagent Co., Ltd., thiab purity yog AR qib);L-lactic acid ( qib tshuaj, PURAC tuam txhab).
1.2 Kev npaj cov khoom sib xyaw
1.2.1 Kev npaj ntawm polylactic acid
Poly-L-lactic acid tau npaj los ntawm txoj kev ncaj qha polycondensation.Ntsuas L-lactic acid aqueous tov nrog ib pawg loj ntawm 90% thiab ntxiv rau lub khob peb-caj dab, lub cev qhuav dej ntawm 150 ° C rau 2 teev nyob rau hauv lub siab ib txwm, tom qab ntawd hnov mob rau 2 teev nyob rau hauv lub tshuab nqus tsev siab ntawm 13300Pa, thiab thaum kawg. react rau 4 teev nyob rau hauv lub tshuab nqus tsev ntawm 3900Pa kom tau ib tug dehydrated prepolymer yam.Tag nrho cov nyiaj ntawm lactic acid aqueous daws rho tawm cov dej tawm yog tag nrho cov nyiaj prepolymer.Ntxiv stannous chloride (feem ntau yog 0.4%) thiab p-toluenesulfonic acid (tus piv ntawm stannous chloride thiab p-toluenesulfonic acid yog 1/1 molar ratio) catalyst system nyob rau hauv lub tau prepolymer, thiab nyob rau hauv condensation Molecular sieves tau ntsia rau hauv lub raj. kom nqus tau me me ntawm cov dej, thiab cov neeg kho tshuab stirring tau khaws cia.Tag nrho cov txheej txheem tau tshwm sim ntawm lub tshuab nqus tsev ntawm 1300 Pa thiab qhov kub ntawm 150 ° C. rau 16 teev kom tau txais cov polymer.Dissolve cov polymer uas tau txais hauv chloroform los npaj ib 5% tov, lim thiab precipitate nrog anhydrous ether rau 24 teev, lim cov precipitate, thiab muab tso rau hauv ib tug -0.1MPa lub tshuab nqus tsev qhov cub ntawm 60 ° C rau 10 mus rau 20 teev kom tau ntshiab qhuav. PLLA polymer.Tus txheeb ze molecular hnyav ntawm PLLA tau txiav txim siab yog 45000-58000 Daltons los ntawm high-performance kua chromatography (GPC).Cov qauv tau khaws cia rau hauv lub tshuab desiccator uas muaj phosphorus pentoxide.
1.2.2 Kev npaj ntawm polylactic acid-ethyl cellulose blend (PLLA-EC)
Ntsuas qhov xav tau ntawm poly-L-lactic acid thiab ethyl cellulose los ua 1% chloroform tov, thiab tom qab ntawd npaj PLLA-EC tov tov.Qhov piv ntawm PLLA-EC tov tov yog: 100/0, 80/20, 60/40, 40/60, 20/80, 0/l00, thawj tus lej sawv cev rau pawg loj ntawm PLLA, thiab tus lej tom qab sawv cev rau loj ntawm EC Fraction.Cov txheej txheem npaj tau nplawm nrog cov hlau nplaum sib nqus rau 1-2 teev, thiab tom qab ntawd nchuav rau hauv lub khob tais kom cia cov chloroform evaporate ib txwm ua rau cov yeeb yaj kiab.Tom qab cov zaj duab xis tau tsim, nws tau muab tso rau hauv lub tshuab nqus tsev qhov cub kom qhuav ntawm qhov kub thiab txias rau 10 teev kom tshem tawm cov chloroform hauv zaj duab xis kom tiav..Cov tshuaj tov yog xim tsis muaj xim thiab pob tshab, thiab cov yeeb yaj kiab sib xyaw kuj tsis muaj xim thiab pob tshab.Cov sib tov tau qhuav thiab khaws cia rau hauv lub tshuab desiccator rau kev siv tom qab.
1.2.3 Kev npaj ntawm polylactic acid-methylcellulose blend (PLLA-MC)
Ntsuas qhov xav tau ntawm poly-L-lactic acid thiab methyl cellulose los ua 1% trifluoroacetic acid daws raws li.PLLA-MC muab zaj duab xis tau npaj los ntawm tib txoj kev raws li PLLA-EC blend film.Cov sib tov tau qhuav thiab khaws cia rau hauv lub tshuab desiccator rau kev siv tom qab.
1.3 Kev xeem ua haujlwm
MANMNA IR-550 infrared spectrometer (Nicolet.Corp) ntsuas qhov infrared spectrum ntawm polymer (KBr ntsiav tshuaj).DSC2901 sib txawv scanning calorimeter (TA tuam txhab) tau siv los ntsuas qhov DSC nkhaus ntawm cov qauv, cov cua kub yog 5 ° C / min, thiab cov iav hloov kub, melting point thiab crystallinity ntawm cov polymer raug ntsuas.Siv Rigaku.Lub D-MAX / Rb diffractometer tau siv los kuaj X-ray diffraction qauv ntawm cov polymer los kawm txog crystallization zog ntawm cov qauv.
2. Cov txiaj ntsig thiab kev sib tham
2.1 Infrared spectroscopy tshawb fawb
Fourier transform infrared spectroscopy (FT-IR) tuaj yeem kawm txog kev cuam tshuam ntawm cov khoom sib xyaw los ntawm kev xav ntawm qib molecular.Yog hais tias ob homopolymers sib xws, hloov ntawm zaus, kev hloov hauv kev siv, thiab txawm tias qhov tsos lossis ploj ntawm cov yam ntxwv ntawm cov khoom tuaj yeem pom.Yog hais tias ob homopolymer tsis sib xws, qhov spectrum ntawm kev sib xyaw yog tsuas yog superposition ntawm ob homopolymers.Nyob rau hauv PLLA spectrum, muaj ib tug stretching vibration ncov ntawm C = 0 ntawm 1755cm-1, lub ncov tsis muaj zog ntawm 2880cm-1 tshwm sim los ntawm C-H stretching vibration ntawm pawg methine, thiab ib tug dav band ntawm 3500 cm-1 yog tshwm sim los ntawm terminal hydroxyl pawg.Nyob rau hauv EC spectrum, tus yam ntxwv ncov ntawm 3483 cm-1 yog lub OH stretching vibration ncov, qhia tias muaj O-H pawg nyob rau hauv molecular saw, thaum 2876-2978 cm-1 yog lub C2H5 stretching vibration ncov, thiab 1637 cm-1 yog HOH Bending vibration ncov (ua los ntawm cov qauv nqus dej).Thaum PLLA sib xyaw nrog EC, nyob rau hauv IR spectrum ntawm hydroxyl cheeb tsam ntawm PLLA-EC blend, O-H ncov hloov mus rau qis wavenumber nrog qhov nce ntawm EC cov ntsiab lus, thiab mus txog qhov tsawg kawg nkaus thaum PLLA / Ec yog 40/60 wavenumber, thiab tom qab ntawd hloov mus rau ntau dua wavenumbers, qhia tias kev sib cuam tshuam ntawm PUA thiab 0-H ntawm EC yog complex.Hauv thaj tsam C = O kev vibration ntawm 1758cm-1, C = 0 ncov ntawm PLLA-EC me ntsis hloov mus rau qis nthwv dej nrog qhov nce ntawm EC, uas qhia tias kev sib cuam tshuam ntawm C = O thiab OH ntawm EC tsis muaj zog.
Nyob rau hauv spectrogram ntawm methylcellulose, tus yam ntxwv ncov ntawm 3480cm-1 yog O-H stretching vibration ncov, uas yog, muaj cov seem O-H pawg ntawm MC molecular saw, thiab HOH dabtsi yog khoov vibration ncov yog 1637cm-1, thiab MC ratio EC yog ntau hygroscopic.Zoo ib yam li PLLA-EC blend system, nyob rau hauv infrared spectra ntawm hydroxyl cheeb tsam ntawm PLLA-EC blend, O-H ncov hloov nrog qhov nce ntawm MC cov ntsiab lus, thiab muaj qhov tsawg kawg nkaus yoj tus naj npawb thaum PLLA / MC yog 70/30 ib.Hauv cheeb tsam C = O vibration (1758 cm-1), C = O ncov me ntsis hloov mus rau qis wavenumbers nrog ntxiv ntawm MC.Raws li peb tau hais ua ntej lawm, muaj ntau pawg hauv PLLA uas tuaj yeem tsim kev sib cuam tshuam tshwj xeeb nrog lwm cov polymers, thiab cov txiaj ntsig ntawm infrared spectrum tuaj yeem yog qhov sib xyaw ua ke ntawm ntau qhov kev sib cuam tshuam tshwj xeeb.Hauv kev sib xyaw ua ke ntawm PLLA thiab cellulose ether, tej zaum yuav muaj ntau hom hydrogen daim ntawv cog lus ntawm ester pawg PLLA, pawg davhlau ya nyob twg hydroxyl thiab pawg ether ntawm cellulose ether (EC lossis MG), thiab lwm pawg hydroxyl.PLLA thiab EC lossis MCs tuaj yeem ua tau ib feem.Tej zaum nws yuav yog vim muaj thiab muaj zog ntawm ntau daim ntawv cog lus hydrogen, yog li cov kev hloov hauv O-H cheeb tsam tseem ceeb dua.Txawm li cas los xij, vim muaj kev cuam tshuam tsis zoo ntawm pawg cellulose, hydrogen bond ntawm C = O pawg ntawm PLLA thiab O-H pawg ntawm cellulose ether tsis muaj zog.
2.2 DSC kev tshawb fawb
DSC nkhaus ntawm PLLA, EC thiab PLLA-EC sib xyaw.Cov iav hloov pauv kub Tg ntawm PLLA yog 56.2 ° C, cov crystal melting kub Tm yog 174.3 ° C, thiab crystallinity yog 55.7%.EC yog ib qho amorphous polymer nrog Tg ntawm 43 ° C thiab tsis muaj melting kub.Lub Tg ntawm ob lub Cheebtsam ntawm PLLA thiab EC yog ze heev, thiab ob qhov kev hloov pauv hauv cheeb tsam sib tshooj thiab tsis tuaj yeem sib txawv, yog li nws nyuaj rau siv los ua qhov kev ntsuas rau kev sib raug zoo.Nrog rau qhov nce ntawm EC, Tm ntawm PLLA-EC sib xyaw tau txo qis me ntsis, thiab cov crystallinity poob qis (qhov crystallinity ntawm cov qauv nrog PLLA / EC 20/80 yog 21.3%).Lub Tm ntawm kev sib tov tau txo qis nrog qhov nce ntawm MC cov ntsiab lus.Thaum PLLA / MC qis dua 70/30, Tm ntawm kev sib xyaw yog qhov nyuaj rau kev ntsuas, uas yog, yuav luag amorphous sib tov tuaj yeem tau txais.Kev txo qis ntawm cov ntsiab lus melting ntawm kev sib xyaw ntawm crystalline polymers nrog amorphous polymers feem ntau yog vim ob qho laj thawj, ib qho yog dilution nyhuv ntawm amorphous tivthaiv;lwm yam tej zaum yuav muaj teeb meem xws li ib tug txo nyob rau hauv crystallization perfection los yog siv lead ua loj ntawm crystalline polymer.Cov txiaj ntsig ntawm DSC tau qhia tias nyob rau hauv kev sib xyaw ua ke ntawm PLLA thiab cellulose ether, ob lub ntsiab lus yog ib feem sib xws, thiab cov txheej txheem crystallization ntawm PLLA nyob rau hauv qhov sib tov yog inhibited, ua rau txo qis ntawm Tm, crystallinity thiab siv lead ua loj ntawm PLLA.Qhov no qhia tau hais tias ob lub ntsiab lus sib raug zoo ntawm PLLA-MC system yuav zoo dua li ntawm PLLA-EC system.
2.3 X-ray diffraction
XRD nkhaus ntawm PLLA muaj qhov siab tshaj plaws ntawm 2θ ntawm 16.64 °, uas sib haum rau 020 siv lead ua dav hlau, thaum lub ncov ntawm 2θ ntawm 14.90 °, 19.21 ° thiab 22.45 ° sib haum rau 101, 023, thiab 121.Nto, uas yog, PLLA yog α-crystalline qauv.Txawm li cas los xij, tsis muaj cov qauv siv lead ua lub ncov hauv qhov nkhaus diffraction ntawm EC, uas qhia tau tias nws yog cov qauv amorphous.Thaum PLLA sib xyaw nrog EC, lub ncov ntawm 16.64 ° maj mam nthuav dav, nws qhov kev siv zog tsis muaj zog, thiab nws txav me ntsis mus rau lub kaum sab xis.Thaum EC cov ntsiab lus yog 60%, lub ncov crystallization tau tawg.Nqaim x-ray diffraction peaks qhia siab crystallinity thiab loj grain loj.Qhov dav qhov diffraction ncov, qhov me me ntawm cov nplej loj.Kev hloov pauv ntawm qhov sib txawv ntawm lub ncov mus rau lub kaum sab xis qhia tias qhov sib txawv ntawm cov nplej nce, uas yog, kev ncaj ncees ntawm cov siv lead ua txo qis.Muaj hydrogen daim ntawv cog lus ntawm PLLA thiab Ec, thiab cov qoob loo loj thiab crystallinity ntawm PLLA txo, uas tej zaum yuav yog vim EC yog ib feem sib xws nrog PLLA los tsim cov qauv amorphous, yog li txo qhov kev ncaj ncees ntawm cov qauv siv lead ua ntawm cov khoom sib xyaw.X-ray diffraction cov txiaj ntsig ntawm PLLA-MC kuj tseem cuam tshuam cov txiaj ntsig zoo sib xws.X-ray diffraction nkhaus qhia txog cov txiaj ntsig ntawm qhov piv ntawm PLLA / cellulose ether ntawm cov qauv ntawm kev sib xyaw, thiab cov txiaj ntsig tau zoo ib yam nrog cov txiaj ntsig ntawm FT-IR thiab DSC.
3. Cov lus xaus
Kev sib xyaw ua ke ntawm poly-L-lactic acid thiab cellulose ether (ethyl cellulose thiab methyl cellulose) tau kawm ntawm no.Kev sib raug zoo ntawm ob lub ntsiab lus hauv kev sib xyaw ua ke tau kawm los ntawm FT-IR, XRD thiab DSC.Cov txiaj ntsig tau pom tias kev sib txuas ntawm hydrogen muaj nyob nruab nrab ntawm PLLA thiab cellulose ether, thiab ob qho tib si hauv lub cev tau sib haum.Ib qho kev txo qis hauv PLLA / cellulose ether piv ua rau txo qis ntawm cov ntsiab lus melting, crystallinity, thiab siv lead ua kev ntseeg siab ntawm PLLA hauv kev sib xyaw, ua rau kev npaj sib xyaw ntawm cov crystallinity sib txawv.Yog li, cellulose ether tuaj yeem siv los hloov kho poly-L-lactic acid, uas yuav muab cov kev ua tau zoo ntawm polylactic acid thiab cov nqi qis ntawm cellulose ether, uas yog qhov tsim nyog rau kev npaj cov ntaub ntawv biodegradable polymer.
Post lub sij hawm: Jan-13-2023