Isixazululo esixubile se-poly-L-lactic acid ne-ethyl cellulose ku-chloroform kanye nesisombululo esixubile se-PLLA ne-methyl cellulose ku-trifluoroacetic acid salungiswa, futhi inhlanganisela ye-PLLA/cellulose ether yalungiswa ngokusakazwa;Imixube etholiwe ibonakale nge-leaf transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) kanye ne-X-ray diffraction (XRD).Kukhona ibhondi ye-hydrogen phakathi kwe-PLLA ne-cellulose ether, futhi izingxenye ezimbili zihambisana ngokwengxenye.Ngokukhula kokuqukethwe kwe-cellulose ether ekuhlanganisweni, indawo encibilikayo, icrystallinity kanye nobuqotho bekristalu benhlanganisela kuzokwehla konke.Uma okuqukethwe kwe-MC kungaphezulu kuka-30%, cishe izingxube ze-amorphous zingatholakala.Ngakho-ke, i-cellulose ether ingasetshenziswa ukuguqula i-poly-L-lactic acid ukuze kulungiswe izinto ze-polymer ezonakele ezinezakhiwo ezahlukene.
Amagama angukhiye: i-poly-L-lactic acid, i-ethyl cellulose,i-methyl cellulose, ukuxuba, i-cellulose ether
Ukuthuthukiswa kanye nokusetshenziswa kwama-polymers emvelo kanye nezinto zokwenziwa ze-polymer ezonakele kuzosiza ukuxazulula inkinga yezemvelo kanye nenkinga yezinsiza abantu ababhekene nazo.Eminyakeni yamuva nje, ucwaningo mayelana nokuhlanganiswa kwezinto ze-polymer ezibolayo zisebenzisa izinsiza ezivuselelekayo njengezinto zokusetshenziswa ze-polymer ludonse ukunaka okubanzi.I-Polylactic acid ingenye ye-aliphatic polyester ebalulekile ewohlokayo.I-lactic acid ingakhiqizwa ngokuvutshelwa kwezitshalo (njengommbila, amazambane, i-sucrose, njll.), futhi ingaboliswa yizinambuzane.Iwumthombo ovuselelekayo.I-Polylactic acid ilungiswa nge-lactic acid nge-polycondensation eqondile noma i-polymerization yokuvula indandatho.Umkhiqizo wokugcina wokuwohloka kwayo yi-lactic acid, engeke ingcolise imvelo.I-PIA inezakhiwo ezinhle kakhulu zemishini, ukucutshungulwa, ukubola kwe-biodegradability kanye ne-biocompatibility.Ngakho-ke, i-PLA ayinakho nje kuphela uhlelo olubanzi lwezinhlelo zokusebenza emkhakheni wobunjiniyela bezinto eziphilayo, kodwa futhi inezimakethe ezinkulu ezingase zibe khona emkhakheni wezingubo zokumboza, amapulasitiki, nezindwangu.
Izindleko eziphezulu ze-poly-L-lactic acid kanye nokukhubazeka kwayo kokusebenza okufana ne-hydrophobicity kanye ne-brittleness kukhawulela ububanzi bokusebenza kwayo.Ukuze kuncishiswe izindleko zayo futhi kuthuthukiswe ukusebenza kwe-PLLA, ukulungiswa, ukuhambisana, i-morphology, i-biodegradability, izakhiwo zemishini, ibhalansi ye-hydrophilic / hydrophobic kanye nezinkambu zokusetshenziswa kwe-polylactic acid copolymers kanye nezingxube ziye zacutshungulwa ngokujulile.Phakathi kwazo, i-PLLA yakha inhlanganisela ehambisanayo ne-poly DL-lactic acid, i-polyethylene oxide, i-polyvinyl acetate, i-polyethylene glycol, njll. emvelweni.Okuphuma ku-cellulose yizinto zokuqala ze-polymer zemvelo ezakhiwa abantu, okubaluleke kakhulu okuyi-cellulose ethers kanye ne-cellulose esters.M.Nagata et al.wafunda uhlelo lwe-PLLA/cellulose blend system futhi wathola ukuthi lezi zingxenye ezimbili azihambisani, kodwa izakhiwo ze-crystallization kanye nokuwohloka kwe-PLLA zathinteka kakhulu ingxenye ye-cellulose.N.U-Ogata et al wafunda ukusebenza nokwakheka kwe-PLLA kanye nesistimu yokuhlanganisa i-cellulose acetate.Ilungelo lobunikazi laseJapan liphinde lafunda ukubola kwe-PLLA nezingxube ze-nitrocellulose.Y.UTeramoto et al wafunda ukulungiswa, izakhiwo ezishisayo nemishini ye-PLLA kanye ne-cellulose diacetate graft copolymers.Kuze kube manje, kukhona izifundo ezimbalwa kakhulu ohlelweni lokuhlanganisa i-polylactic acid ne-cellulose ether.
Eminyakeni yamuva nje, iqembu lethu liye lahlanganyela ocwaningweni lwe-copolymerization eqondile kanye nokuguqulwa kokuxutshwa kwe-polylactic acid namanye ama-polymers.Ukuze kuhlanganiswe izici ezinhle kakhulu ze-polylactic acid nezindleko eziphansi ze-cellulose kanye nokuphuma kwayo ukuze kulungiswe izinto ze-polymer ezibolayo ngokuphelele, sikhetha i-cellulose (i-ether) njengengxenye eguquliwe yokuguqulwa kokuxutshwa.I-Ethyl cellulose ne-methyl cellulose zingama-ether amabili abalulekile e-cellulose.I-Ethyl cellulose iyi-alkyl ether engancibiliki emanzini engeyona ionic cellulose, engasetshenziswa njengezinto zokwelapha, amapulasitiki, izinto zokunamathisela kanye nama-textile finishing agents.I-Methyl cellulose iyancibilika emanzini, inokumanzisa okuhle kakhulu, ukubumbana, ukugcinwa kwamanzi kanye nezakhiwo zefilimu, futhi isetshenziswa kabanzi emkhakheni wezinto zokwakha, izambatho, izimonyo, imithi kanye nokwenza amaphepha.Lapha, izingxube ze-PLLA/EC kanye ne-PLLA/MC zalungiswa ngendlela yokukhipha isixazululo, futhi kwaxoxwa ngokuhambisana, izakhiwo ezishisayo kanye ne-crystallization ye-PLLA/cellulose ether blends.
1. Ingxenye yokuhlola
1.1 Izinto ezisetshenziswayo
I-Ethyl cellulose (AR, i-Tianjin Huazhen Special Chemical Reagent Factory);i-methyl cellulose (MC450), i-sodium dihydrogen phosphate, i-disodium hydrogen phosphate, i-ethyl acetate, i-stannous isooctanoate, i-chloroform (okungenhla yonke imikhiqizo ye-Shanghai Chemical Reagent Co., Ltd., futhi ukuhlanzeka kuyibanga le-AR);I-L-lactic acid (ibanga lezemithi, inkampani ye-PURAC).
1.2 Ukulungiswa kwezingxube
1.2.1 Ukulungiswa kwe-polylactic acid
I-Poly-L-lactic acid yalungiswa ngendlela eqondile ye-polycondensation.Kala isixazululo samanzi se-L-lactic acid ngengxenye enkulu engu-90% bese uyifaka eflaskini enezintamo ezintathu, dehydrate ku-150 ° C amahora angu-2 ngaphansi kwengcindezi evamile, bese usabela amahora angu-2 ngaphansi kwengcindezi ye-vacuum engu-13300Pa, futhi ekugcineni. sabela amahora angu-4 ngaphansi kwe-vacuum ye-3900Pa ukuze uthole izinto ze-prepolymer ezingenamanzi.Isamba senani lesixazululo se-lactic acid esimanzi uma kukhishwe okukhiphayo kwamanzi yisamba senani le-prepolymer.Faka i-stannous chloride (ingxenyana yobuningi ingu-0.4%) kanye ne-p-toluenesulfoonic acid (isilinganiso se-stannous chloride ne-p-toluenesulfoonic acid yi-1/1 ye-molar ratio) isistimu ye-catalyst ku-prepolymer etholiwe, futhi ekuhlanganiseni izisefo ze-molecular zafakwa eshubhuni. ukumunca amanzi amancane, futhi ukunyakaziswa komshini kwagcinwa.Lonke uhlelo lwasabela ku-vacuum ye-1300 Pa kanye nezinga lokushisa lika-150 ° C. amahora angu-16 ukuthola i-polymer.Chaza i-polymer etholiwe ku-chloroform ukuze ulungise isixazululo esingu-5%, ukuhlunga kanye nemvula nge-ether engenamanzi amahora angu-24, uhlunge imvula, futhi uyibeke kuhhavini yokuhlanza engu-0.1MPa ku-60 ° C amahora angu-10 kuya kwangu-20 ukuze uthole I-Pure dry. I-PLA polymer.Isisindo samangqamuzana esihlobene se-PLLA etholiwe sinqunywe ukuthi singama-45000-58000 Daltons nge-high-performance liquid chromatography (GPC).Amasampula agcinwe ku-deiccator equkethe i-phosphorus pentoxide.
1.2.2 Ukulungiswa kwe-polylactic acid-ethyl cellulose blend (PLLA-EC)
Kala inani elidingekayo le-poly-L-lactic acid ne-ethyl cellulose ukuze wenze isixazululo se-chloroform esingu-1% ngokulandelana, bese ulungiselela isisombululo esixubile se-PLLA-EC.Isilinganiso sesixazululo esixubile se-PLLA-EC sithi: 100/0, 80/20, 60/40, 40/60, 20/80, 0/l00, inombolo yokuqala imele ingxenye enkulu ye-PLLA, kanti inombolo yokugcina imele Ubuningi be-EC Fraction.Izixazululo ezilungisiwe zashukunyiswa nge-stirrer magnetic amahora angu-1-2, bese zithululelwa endishini yengilazi ukuze i-chloroform iqhume ngokwemvelo ukuze yenze ifilimu.Ngemuva kokuthi ifilimu yenziwe, ifakwe kuhhavini ye-vacuum ukuze yome ekushiseni okuphansi amahora angu-10 ukuze isuse ngokuphelele i-chloroform efilimu..Isixazululo senhlanganisela asinambala futhi sisobala, futhi ifilimu ehlanganisiwe nayo ayinambala futhi isobala.Inhlanganisela yomiswa futhi yagcinwa ku-desiccator ukuze isetshenziswe kamuva.
1.2.3 Ukulungiswa kwe-polylactic acid-methylcellulose blend (PLLA-MC)
Kala inani elidingekayo le-poly-L-lactic acid ne-methyl cellulose ukwenza isixazululo se-trifluoroacetic acid esingu-1% ngokulandelana.Ifilimu yenhlanganisela ye-PLLA-MC ilungiswe ngendlela efanayo neyefilimu yenhlanganisela ye-PLLA-EC.Inhlanganisela yomiswa futhi yagcinwa ku-desiccator ukuze isetshenziswe kamuva.
1.3 Ukuhlolwa kokusebenza
I-MANMNA IR-550 i-infrared spectrometer (Nicolet.Corp) ilinganise i-spectrum ye-infrared ye-polymer (ithebhulethi ye-KBr).I-DSC2901 differential scanning calorimeter (inkampani ye-TA) yasetshenziswa ukukala ijika le-DSC lesampula, izinga lokushisa lalingu-5°C/min, kanye nezinga lokushisa lokushintsha kwengilazi, indawo yokuncibilika kanye nobukristalu be-polymer kukalwa.Sebenzisa i-Rigaku.I-D-MAX/Rb diffractometer isetshenziselwe ukuhlola iphethini ye-X-ray diffraction ye-polymer ukuze kufundwe izici ze-crystallization zesampula.
2. Imiphumela kanye nengxoxo
2.1 Ucwaningo lwe-infrared spectroscopy
I-Fourier transform infrared spectroscopy (FT-IR) ingafunda ukusebenzisana phakathi kwezingxenye zenhlanganisela ngokombono weleveli yamangqamuzana.Uma ama-homopolymers amabili ehambisana, ukuguquguquka kwemvamisa, izinguquko zokuqina, ngisho nokubukeka noma ukunyamalala kweziqongo zophawu lwezingxenye kungabonwa.Uma ama-homopolymer amabili engahambisani, i-spectrum ye-blend imane iwukugxumela phezulu kwama-homopolymer amabili.Ku-spectrum ye-PLLA, kukhona ukuphakama kokudlidliza okunwebekayo okungu-C=0 ku-1755cm-1, ukuphakama okubuthakathaka ku-2880cm-1 okubangelwa ukudlidliza okwelula kwe-C—H kweqembu le-methine, kanye nebhendi ebanzi ku-3500 cm-1 okubangelwa amaqembu e-terminal hydroxyl.Ku-EC spectrum, isiqongo sesici esingu-3483 cm-1 siyisiqongo sokudlidliza se-OH esinwebekayo, okubonisa ukuthi kunamaqembu e-O—H asele kuchungechunge lwamangqamuzana, kuyilapho u-2876-2978 cm-1 kuyi-C2H5 enwebekayo yokudlidliza, kanye no-1637. I-cm-1 i-HOH Ukugoba ukuphakama kokudlidliza (okubangelwa isampula elimunca amanzi).Lapho i-PLLA ixutshwa ne-EC, ku-IR spectrum ye-hydroxyl esifundeni se-PLLA-EC ehlanganisiwe, inani eliphakeme le-O—H lishintshela kunombolo yegagasi eliphansi ngokunyuka kokuqukethwe kwe-EC, futhi lifinyelele ubuncane lapho i-PLLA/Ec iyinombolo yegagasi engu-40/60, bese ishintshelwa kuzinombolo zamagagasi aphezulu, okubonisa ukuthi ukusebenzisana phakathi kwe-PUA no-0-H ye-EC kuyinkimbinkimbi.Esifundeni sokudlidliza se-C=O esingu-1758cm-1, isiqongo se-C=0 se-PLLA-EC sishintshe kancane siye kwinombolo yegagasi ephansi ngokunyuka kwe-EC, okubonise ukuthi ukusebenzisana phakathi kwe-C=O ne-OH ye-EC bekubuthakathaka.
Ku-spectrogram ye-methylcellulose, isiqongo esiyisici esingu-3480cm-1 siyisiqongo sokudlidliza esinwebekayo se-O—H, okungukuthi, kunamaqembu asele e-O—H ochungechungeni lwamangqamuzana e-MC, futhi inani eliphakeme lokudlidliza le-HOH liku-1637cm-1, futhi isilinganiso se-MC EC sine-hygroscopic.Ngokufana nesistimu yokuhlanganisa ye-PLLA-EC, ku-spectra ye-infrared yesifunda se-hydroxyl yenhlanganisela ye-PLLA-EC, isiqongo se-O—H siyashintsha ngokukhula kokuqukethwe kwe-MC, futhi sinenombolo yegagasi elincane lapho i-PLLA/MC 70/30.Esifundeni sokudlidliza se-C=O (1758 cm-1), isiqongo se-C=O sishintsha kancane siye kuzinombolo zamagagasi aphansi ngokungezwa kwe-MC.Njengoba sishilo ekuqaleni, kunamaqembu amaningi ku-PLA angakha ukusebenzisana okukhethekile namanye ama-polymer, futhi imiphumela ye-spectrum ye-infrared ingase ibe umphumela ohlangene wokusebenzisana okuningi okukhethekile okungenzeka.Kuhlelo lokuhlanganisa lwe-PLLA ne-cellulose ether, kungase kube amafomu ahlukahlukene ebhondi ye-hydrogen phakathi kweqembu le-ester le-PLLA, iqembu le-terminal hydroxyl kanye neqembu le-ether le-cellulose ether (EC noma MG), kanye namaqembu e-hydroxyl asele.I-PLLA ne-EC noma i-MCs ingase ihambisane kancane.Kungase kube ngenxa yobukhona namandla amabhondi e-hydrogen amaningi, ngakho-ke izinguquko endaweni ye-O—H zibaluleke kakhulu.Nokho, ngenxa yesithiyo esiqinile seqembu le-cellulose, isibopho se-hydrogen phakathi kweqembu le-C=O le-PLLA neqembu le-O—H le-cellulose ether libuthakathaka.
2.2 Ucwaningo lwe-DSC
Amajika e-DSC enhlanganisela ye-PLLA, EC kanye ne-PLLA-EC.Izinga lokushisa lokushintsha kwengilazi Tg of PLLA lingu-56.2 ° C, izinga lokushisa elincibilikayo le-crystal Tm lingu-174.3 ° C, futhi icrystallinity ingu-55.7%.I-EC i-amorphous polymer ene-Tg engu-43°C futhi ayinakho izinga lokushisa elincibilikayo.I-Tg yezingxenye ezimbili ze-PLLA ne-EC zisondelene kakhulu, futhi izifunda ezimbili zoguquko ziyagqagqana futhi azikwazi ukuhlukaniswa, ngakho-ke kunzima ukuyisebenzisa njengendlela yokunquma ukuhambisana kwesistimu.Ngokukhula kwe-EC, i-Tm ye-PLLA-EC izingxube zehla kancane, futhi i-crystallinity yehla (i-crystallinity yesampula nge-PLLA/EC 20/80 yayingu-21.3%).I-TM yama-blends yehla ngokunyuka kokuqukethwe kwe-MC.Uma i-PLLA/MC ingaphansi kuka-70/30, i-Tm yenhlanganisela kunzima ukuyikala, okungukuthi, cishe ukuhlanganiswa kwe-amorphous kungatholakala.Ukwehliswa kwephuzu lokuncibilika kwezingxube ze-crystalline polymers nama-polymers amorphous ngokuvamile kungenxa yezizathu ezimbili, esinye siwumphumela wokuhlanjululwa kwengxenye ye-amorphous;okunye kungase kube imiphumela yesakhiwo njengokunciphisa ukuphelela kwe-crystallization noma usayizi wekristalu we-polymer ye-crystalline.Imiphumela ye-DSC ibonise ukuthi ohlelweni lokuhlanganisa lwe-PLLA ne-cellulose ether, izingxenye ezimbili zazihambisana kancane, futhi inqubo ye-crystallization ye-PLLA engxubeni yavinjelwa, okuholele ekunciphiseni kwe-Tm, i-crystallinity kanye nosayizi wekristalu we-PLA.Lokhu kubonisa ukuthi ukuhambisana kwezingxenye ezimbili zohlelo lwe-PLLA-MC kungase kube ngcono kunohlelo lwe-PLLA-EC.
2.3 I-X-ray diffraction
Ijika le-XRD le-PLLA linokuphakama okuqine kakhulu ku-2θ ka-16.64°, elihambisana nendiza yekristalu engu-020, kuyilapho iziqongo eziku-2θ ka-14.90°, 19.21° kanye no-22.45° zihambisana no-101, 023, kanye nekristalu engu-121 ngokulandelanayo.Ubuso, okungukuthi, i-PLA iyisakhiwo se-α-crystalline.Kodwa-ke, asikho isiqongo sesakhiwo sekristalu ejikeni le-diffraction ye-EC, ekhombisa ukuthi iyisakhiwo se-amorphous.Lapho i-PLLA ixutshwa ne-EC, inani eliphakeme elingu-16.64° lanwetshwa kancane kancane, ukuqina kwayo kwaba buthakathaka, futhi yanyakaza kancane yaya engeli ephansi.Lapho okuqukethwe kwe-EC kungu-60%, inani eliphakeme lokucwebezela lase lihlakazekile.Iziqongo ze-x-ray diffraction eziwumngcingo zibonisa ubucwebe obuphezulu kanye nosayizi omkhulu wokusanhlamvu.Ububanzi bokuphakama kwe-diffraction, buncane usayizi wokusanhlamvu.Ukushintsha kwe-diffraction peak ibe i-engeli ephansi kubonisa ukuthi ukuhlukana kokusanhlamvu kuyanda, okungukuthi, ubuqotho bekristalu buyancipha.Kukhona isibopho se-hydrogen phakathi kwe-PLLA ne-Ec, futhi usayizi wokusanhlamvu nokucwebezela kwe-PLLA kwehla, okungenzeka kungenxa yokuthi i-EC ihambisana ngokwengxenye ne-PLLA ukuze yakhe isakhiwo se-amorphous, ngaleyo ndlela yehlise ubuqotho besakhiwo sekristalu senhlanganisela.Imiphumela ye-X-ray diffraction ye-PLLA-MC nayo ibonisa imiphumela efanayo.Ijika le-X-ray diffraction libonisa umphumela wesilinganiso se-PLLA/cellulose ether esakhiweni senhlanganisela, futhi imiphumela ihambisana ngokuphelele nemiphumela ye-FT-IR ne-DSC.
3. Isiphetho
Uhlelo lwenhlanganisela ye-poly-L-lactic acid ne-cellulose ether (i-ethyl cellulose ne-methyl cellulose) yafundwa lapha.Ukuhambisana kwezingxenye ezimbili ohlelweni lwenhlanganisela kwacwaningwa nge-FT-IR, XRD kanye ne-DSC.Imiphumela yabonisa ukuthi i-hydrogen bonding yayikhona phakathi kwe-PLLA ne-cellulose ether, futhi izingxenye ezimbili ohlelweni zazihambisana ngokwengxenye.Ukuncipha kwesilinganiso se-PLLA/cellulose ether kubangela ukuncipha kwendawo encibilikayo, icrystallinity, kanye nobuqotho bekristalu be-PLLA enhlanganisela, okuholela ekulungiseleleni izingxube zekristalu ehlukene.Ngakho-ke, i-cellulose ether ingasetshenziselwa ukuguqula i-poly-L-lactic acid, ezohlanganisa ukusebenza okuhle kakhulu kwe-polylactic acid kanye nezindleko eziphansi ze-cellulose ether, okuhambisana nokulungiswa kwezinto ze-polymer ezibolayo ngokuphelele.
Isikhathi sokuthumela: Jan-13-2023