Isisombululo esixubileyo se-poly-L-lactic acid kunye ne-ethyl cellulose kwi-chloroform kunye nesisombululo esixubileyo se-PLLA kunye ne-methyl cellulose kwi-trifluoroacetic acid yalungiswa, kwaye i-PLLA / cellulose ether blend yalungiswa ngokuphosa; Imixube efunyenweyo ibonakaliswe nge-leaf transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) kunye ne-X-ray diffraction (XRD). Kukho ibhondi ye-hydrogen phakathi kwe-PLLA kunye ne-cellulose ether, kwaye la macandelo mabini ahambelana ngokuyinxenye. Ngokunyuka komxholo we-cellulose ether kwi-blend, indawo yokuncibilika, i-crystallinity kunye ne-crystal integrity ye-blend yonke iya kuncipha. Xa umxholo we-MC uphezulu kune-30%, phantse imixube ye-amorphous inokufumaneka. Ngoko ke, i-cellulose ether ingasetyenziselwa ukuguqula i-poly-L-lactic acid ukulungiselela izinto ezichithwayo zepolymer ezineempawu ezahlukeneyo.
Amagama angundoqo: i-poly-L-lactic acid, i-ethyl cellulose,i-methyl cellulose, ukudibanisa, i-cellulose ether
Uphuhliso kunye nokusetyenziswa kweepolymers zendalo kunye nemathiriyeli yokwenziwa kwepolymer eyonakalisayo kuya kunceda ukusombulula ingxaki yokusingqongileyo kunye nengxaki yemithombo ejongene nabantu. Kwiminyaka yakutshanje, uphando malunga nokudityaniswa kwezixhobo zepolymer ezinokuthi zihlaziywe kusetyenziswa izixhobo ezivuselelwayo njengemathiriyeli ekrwada yepolymer itsale ingqalelo ebanzi. I-Polylactic acid yenye yezona zinto zibalulekileyo ze-aliphatic polyesters. I-asidi ye-lactic inokuveliswa ngokuvundiswa kwezityalo (ezifana nombona, iitapile, i-sucrose, njl.), kwaye inokubola nge-microorganisms. Ngumthombo ohlaziyekayo. I-Polylactic acid ilungiswa ukusuka kwi-lactic acid nge-polycondensation ngqo okanye i-polymerization yokuvula i-ring. Imveliso yokugqibela yokuthotywa kwayo yi-lactic acid, engayi kungcolisa indalo. I-PIA ineepropathi ezigqwesileyo zoomatshini, ukuqhubekeka, ukuguquguquka kwezinto eziphilayo kunye ne-biocompatibility. Ke ngoko, i-PLA ayinayo kuphela uluhlu olubanzi lwezicelo kwinkalo yobunjineli bebhayoloji, kodwa ikwaneemarike ezinkulu ezinokubakho kwimimandla yeengubo, iiplastiki, kunye nelaphu.
Iindleko eziphezulu ze-poly-L-lactic acid kunye neziphene zayo zokusebenza ezifana ne-hydrophobicity kunye ne-brittleness umda wokusetyenziswa kwayo. Ukuze kuncitshiswe iindleko zayo kunye nokuphucula ukusebenza kwe-PLLA, ukulungiswa, ukuhambelana, i-morphology, i-biodegradability, i-mechanical properties, i-hydrophilic / hydrophobic balance kunye neendawo zokusebenzisa i-polylactic acid copolymers kunye nokudibanisa kuye kwafundwa ngokunzulu. Phakathi kwabo, i-PLLA yenza umxube ohambelanayo kunye ne-poly DL-lactic acid, i-polyethylene oxide, i-polyvinyl acetate, i-polyethylene glycol, njl. kwindalo. I-Cellulose derivatives zezona zinto zakuqala zepolymer zendalo ezenziwe ngabantu, ezona zibalulekileyo kuzo zii-cellulose ethers kunye ne-cellulose esters. M. Nagata et al. wafunda inkqubo yokudibanisa i-PLLA / cellulose kwaye wafumanisa ukuba amacandelo amabini awahambelani, kodwa i-crystallization kunye ne-degradation properties ze-PLLA zachaphazeleka kakhulu yi-cellulose component. N. U-Ogata et al wafunda ukusebenza kunye nesakhiwo se-PLLA kunye ne-cellulose acetate blend system. Ilungelo elilodwa lomenzi wechiza laseJapan liphinde lafunda ukonakaliswa kwe-biodegradability ye-PLLA kunye nemixube ye-nitrocellulose. Y. UTeramoto et al wafunda ukulungiswa, iipropathi ezishushu kunye nezomatshini zePLLA kunye ne-cellulose diacetate graft copolymers. Ukuza kuthi ga ngoku, kukho izifundo ezimbalwa kakhulu kwinkqubo yokuxuba i-polylactic acid kunye ne-cellulose ether.
Kwiminyaka yakutshanje, iqela lethu liye labandakanyeka kuphando lwe-copolymerization ngokuthe ngqo kunye nokudibanisa ukuguqulwa kwe-polylactic acid kunye nezinye iipolymers. Ukuze udibanise iimpawu ezigqwesileyo ze-polylactic acid kunye nexabiso eliphantsi le-cellulose kunye ne-derivatives yalo ukulungiselela izixhobo ze-polymer ngokupheleleyo ze-biodegradable, sikhetha i-cellulose (i-ether) njengenxalenye elungisiweyo yokuguqulwa kokudibanisa. I-Ethyl cellulose kunye ne-methyl cellulose zimbini ezibalulekileyo ze-cellulose ethers. I-Ethyl cellulose yi-alkyl ether engenamanzi engenamanzi, engasetyenziswa njengezinto zonyango, iiplastiki, i-adhesives kunye ne-textile finishing agents. I-Methyl cellulose i-soluble yamanzi, ine-wettability egqwesileyo, ukubambisana, ukugcinwa kwamanzi kunye neepropati zokwenza ifilimu, kwaye isetyenziswa ngokubanzi kwiindawo zokwakha, iingubo, izimonyo, i-pharmaceuticals kunye ne-papermaking. Apha, i-PLLA / EC kunye ne-PLLA / MC iingxube zalungiswa ngendlela yokuphosa isisombululo, kunye nokuhambelana, iimpawu ze-thermal kunye ne-crystallization ye-PLLA / i-cellulose ether blends yaxoxwa.
1. Inxalenye yovavanyo
1.1 Iimathiriyeli ekrwada
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 (ezi ngasentla zizo zonke iimveliso ze-Shanghai Chemical Reagent Co., Ltd., kunye nococeko libakala le-AR); I-L-lactic acid (ibakala leyeza, inkampani ye-PURAC).
1.2 Ukulungiswa kwemixube
1.2.1 Ukulungiswa kwe-polylactic acid
I-Poly-L-lactic acid yalungiswa ngendlela ye-polycondensation ngqo. Ukulinganisa i-L-lactic acid isisombululo se-aqueous kunye neqhekeza elikhulu le-90% kwaye uyongeze kwi-flask enentamo ezintathu, dehydrate kwi-150 ° C kwiiyure ze-2 phantsi koxinzelelo oluqhelekileyo, uze uphendule iiyure ze-2 phantsi koxinzelelo lwe-vacuum ye-13300Pa, kwaye ekugqibeleni. ukusabela kwiiyure ezi-4 phantsi kwe-vacuum ye-3900Pa ukufumana izinto ze-prepolymer ezingenamanzi. Isixa sisonke se-lactic acid yesisombululo esinamanzi thabatha imveliso yamanzi sisixa esipheleleyo se-prepolymer. Yongeza i-stannous chloride (iqhezu lobunzima yi-0.4%) kunye ne-p-toluenesulfonic acid (umlinganiselo we-stannous chloride kunye ne-p-toluenesulfonic acid yi-1/1 ye-molar ratio) inkqubo ye-catalyst kwi-prepolymer efunyenweyo, kwaye kwi-condensation iisefu ze-Molecular zafakwa kwi-tube. ukufunxa umlinganiselo omncinci wamanzi, kwaye ukuvuselela oomatshini kwagcinwa. Yonke inkqubo yaphendulwa kwi-vacuum ye-1300 Pa kunye nokushisa kwe-150 ° C. kwiiyure ze-16 ukufumana i-polymer. Yinyibilikise i-polymer efunyenwe kwi-chloroform ukulungisa isisombululo se-5%, ihluzo kunye ne-ether e-anhydrous iiyure ezingama-24, hluza i-precipitate, kwaye uyibeke kwi-oven vacuum -0.1MPa kwi-60 ° C kwiiyure ezili-10 ukuya kwezingama-20 ukufumana i-Pure dry. I-PLA polymer. Ubunzima be-molecular ye-PLLA efunyenweyo yamiselwa ukuba yi-45000-58000 Daltons nge-high-performance liquid chromatography (GPC). Iisampulu zagcinwa kwi-desiccator ene-phosphorus pentoxide.
1.2.2 Ukulungiswa kwe-polylactic acid-ethyl cellulose blend (PLLA-EC)
Yenza umlinganiselo ofunekayo we-poly-L-lactic acid kunye ne-ethyl cellulose ukwenza isisombululo se-chloroform ye-1% ngokulandelelana, kwaye ulungiselele isisombululo esixutywe se-PLLA-EC. Umlinganiselo we-PLLA-EC isisombululo esixubileyo ngu: 100/0, 80/20, 60/40, 40/60, 20/80, 0/l00, inani lokuqala limele ubuninzi beqhekeza le-PLLA, kwaye inani lokugqibela limele ubunzima be-EC Fraction. Izisombululo ezilungiselelwe zixutywe nge-stirrer magnetic kwiiyure ze-1-2, kwaye zithululelwe kwisitya seglasi ukuvumela ukuba i-chloroform iqhume ngokwemvelo ukwenza ifilimu. Emva kokuba ifilimu yenziwe, ifakwe kwi-oven vacuum ukuze yome kwiqondo lokushisa eliphantsi kwiiyure ezili-10 ukususa ngokupheleleyo i-chloroform kwifilimu. . Isisombululo somxube asinambala kwaye sicacile, kwaye ifilimu yokudibanisa nayo ayinambala kwaye ibonakala. Umxube womisiwe kwaye ugcinwe kwi-desiccator ukuze isetyenziswe kamva.
1.2.3 Ukulungiswa kwe-polylactic acid-methylcellulose blend (PLLA-MC)
Yenza umlinganiselo ofunekayo we-poly-L-lactic acid kunye ne-methyl cellulose ukwenza i-1% yesisombululo se-trifluoroacetic acid ngokulandelelanayo. Ifilimu yokudibanisa i-PLLA-MC yalungiswa ngendlela efanayo nefilimu yokudibanisa i-PLLA-EC. Umxube womisiwe kwaye ugcinwe kwi-desiccator ukuze isetyenziswe kamva.
1.3 Uvavanyo lwentsebenzo
I-MANMNA IR-550 i-infrared spectrometer (Nicolet.Corp) ilinganisa i-infrared spectrum ye-polymer (ithebhulethi ye-KBr). I-DSC2901 i-calorimeter ye-different scanning (inkampani ye-TA) yayisetyenziselwa ukulinganisa ijika le-DSC yesampuli, izinga lokufudumeza laliyi-5 ° C / min, kunye nokushisa kweglasi yokutshintsha, indawo yokunyibilika kunye ne-crystallinity ye-polymer yalinganiswa. Sebenzisa Rigaku. I-D-MAX / Rb diffractometer yayisetyenziselwa ukuvavanya i-X-ray ye-diffraction pattern ye-polymer ukufunda iimpawu ze-crystallization zesampuli.
2. Iziphumo kunye nengxoxo
2.1 Uphando lwe-infrared spectroscopy
I-Fourier transform infrared spectroscopy (FT-IR) inokufunda intsebenziswano phakathi kwamalungu omxube ngokwembono yenqanaba lemolekyuli. Ukuba i-homopolymers ezimbini ziyahambelana, utshintsho kwi-frequency, utshintsho kwi-intensitest, kunye nokubonakala okanye ukunyamalala kweencopho zeempawu zamacandelo kunokubonwa. Ukuba i-homopolymers ezimbini azihambelani, i-spectrum yomxube yi-superposition nje ye-homopolymers ezimbini. Kwi-spectrum ye-PLLA, kukho ukuphakama kwe-vibration ye-C = 0 kwi-1755cm-1, i-peak ebuthakathaka kwi-2880cm-1 ebangelwa yi-C-H yokwelula i-vibration yeqela le-methine, kunye nebhendi ebanzi kwi-3500 cm-1. ebangelwa ngamaqela e-terminal hydroxyl. Kwi-spectrum ye-EC, i-peak yeempawu kwi-3483 cm-1 yi-OH yokwelula i-vibration peak, ebonisa ukuba kukho amaqela e-O-H asele kwikhonkco le-molecular, ngelixa i-2876-2978 cm-1 yi-C2H5 yokwelula i-vibration peak, kunye ne-1637 cm-1 yi HOH Ukugoba incopho yokungcangcazela (okubangelwa yisampuli efunxa amanzi). Xa i-PLLA ixutywe kunye ne-EC, kwi-IR spectrum ye-hydroxyl yengingqi ye-PLLA-EC yokuxuba, i-O-H i-peak itshintshela kwi-wavenumber ephantsi kunye nokunyuka komxholo we-EC, kwaye ifikelele kuncinci xa i-PLLA / Ec i-40/60 wavenumber, kwaye emva koko itshintshelwe kumanani amaza aphezulu, ebonisa ukuba intsebenziswano phakathi kwe-PUA kunye ne-0-H ye-EC inzima. Kwingingqi ye-C = O ye-vibration ye-1758cm-1, i-C = 0 i-peak ye-PLLA-EC itshintshile kancinci ukuya kwinani eliphantsi lamaza kunye nokunyuka kwe-EC, ebonisa ukuba intsebenziswano phakathi kwe-C = O kunye ne-OH ye-EC yayibuthathaka.
Kwi-spectrogram ye-methylcellulose, incopho yeempawu kwi-3480cm-1 yi-O-H yokwelula i-vibration peak, oko kukuthi, kukho amaqela e-O-H ashiyekileyo kwi-MC chain chain, kunye ne-HOH bending vibration peak kwi-1637cm-1, kunye ne-MC ratio EC i-hygroscopic ngaphezulu. Ngokufana nenkqubo yokudibanisa i-PLLA-EC, kwi-infrared spectra yendawo ye-hydroxyl yomxube we-PLLA-EC, i-O-H i-peak itshintsha ngokunyuka komxholo we-MC, kwaye inenani elincinci le-wave wave xa i-PLLA / MC. 70/30. Kummandla we-C=O wokungcangcazela (1758 cm-1), incopho ye-C=O itshintsha kancinane ukuya kumanani amaza asezantsi kunye nokongezwa kwe-MC. Njengoko besesitshilo ngaphambili, kukho amaqela amaninzi kwi-PLA anokwenza unxibelelwano olukhethekileyo kunye nezinye iipolymers, kwaye iziphumo ze-infrared spectrum zinokuba yimpembelelo edibeneyo yokunxibelelana okukhethekileyo okunokwenzeka. Kwinkqubo yokudibanisa ye-PLLA kunye ne-cellulose ether, kunokubakho iifom ezahlukeneyo ze-hydrogen bond phakathi kweqela le-ester le-PLLA, iqela le-terminal hydroxyl kunye neqela le-ether ye-cellulose ether (EC okanye MG), kunye namaqela asele e-hydroxyl. I-PLLA kunye ne-EC okanye ii-MCs zinokuhambelana ngokuyinxenye. Kungenzeka ngenxa yobukho kunye namandla eebhondi ezininzi ze-hydrogen, ngoko ke utshintsho kummandla we-O-H lubaluleke kakhulu. Nangona kunjalo, ngenxa yesithintelo se-steric seqela le-cellulose, ibhondi ye-hydrogen phakathi kwe-C = O yeqela le-PLLA kunye ne-O-H yeqela le-cellulose ether ibuthathaka.
2.2 Uphando lweDSC
Iijika ze-DSC ze-PLLA, i-EC kunye ne-PLLA-EC idibanisa. Ukushisa kweglasi ye-glass Tg ye-PLLA yi-56.2 ° C, i-crystal melting ye-Tm yi-174.3 ° C, kwaye i-crystallinity yi-55.7%. I-EC yipolymer e-amorphous ene-Tg ye-43 ° C kwaye akukho bushushu obunyibilikayo. I-Tg yamacandelo amabini e-PLLA kunye ne-EC isondele kakhulu, kwaye imimandla emibini yenguqu idibanisa kwaye ayinakuhlukaniswa, ngoko kunzima ukuyisebenzisa njengenqobo yokuhambelana kwenkqubo. Ngokunyuka kwe-EC, i-Tm ye-PLLA-EC idibanisa iyancipha kancane, kwaye i-crystallinity yehla (i-crystallinity yesampuli kunye ne-PLLA / EC 20 / 80 yi-21.3%). I-TM yemixube yehla ngokunyuka komxholo we-MC. Xa i-PLLA / MC iphantsi kwe-70/30, i-Tm yomxube inzima ukulinganisa, oko kukuthi, phantse umxube we-amorphous unokufumaneka. Ukwehliswa kwendawo yokunyibilika kweengxube ze-crystalline polymers kunye ne-amorphous polymers ngokuqhelekileyo ngenxa yezizathu ezibini, enye yimpembelelo ye-dilution yecandelo le-amorphous; enye inokuba yimiphumo yesakhiwo njengokunciphisa ukugqibelela kwe-crystallization okanye ubukhulu be-crystal ye-polymer ye-crystalline. Iziphumo ze-DSC zibonise ukuba kwinkqubo yokudibanisa ye-PLLA kunye ne-cellulose ether, amacandelo amabini ayehambelana ngokuyinxalenye, kwaye inkqubo ye-crystallization ye-PLLA kumxube yayinqatshelwe, okubangelwa ukuhla kwe-Tm, i-crystallinity kunye nobukhulu be-crystal ye-PLLA. Oku kubonisa ukuba ukuhambelana kwamacandelo amabini enkqubo ye-PLLA-MC kunokuba ngcono kunenkqubo ye-PLLA-EC.
2.3 I-X-reyi diffraction
I-XRD curve ye-PLLA ineyona nto inamandla kakhulu kwi-2θ ye-16.64 °, ehambelana ne-crystal plane ye-020, ngelixa i-2θ ye-14.90 °, i-19.21 ° kunye ne-22.45 ° ihambelana ne-101, i-023 kunye ne-121 ngokulandelanayo. Umphezulu, oko kukuthi, i-PLA yisakhiwo se-α-crystalline. Nangona kunjalo, akukho ngqungquthela ye-crystal structure kwi-curve ye-diffraction ye-EC, ebonisa ukuba i-amorphous structure. Xa i-PLLA ixutywe ne-EC, incopho ye-16.64 ° yanda ngokuthe ngcembe, ukuqina kwayo kuncipha, kwaye yahamba kancinane kwi-angle ephantsi. Xa umxholo we-EC wawuyi-60%, i-crystallization peak yayihlakazekile. Iincopho ze-x-reyi emxinwa zibonisa ubukhazikhazi obuphezulu kunye nobukhulu obuziinkozo. Ububanzi bencopho ye-diffraction, incinci isayizi yeenkozo. Ukutshintshwa kwe-diffraction peak ukuya kwi-angle ephantsi kubonisa ukuba ukuhlukana kweenkozo kuyanda, oko kukuthi, ingqibelelo ye-crystal iyancipha. Kukho ibhondi ye-hydrogen phakathi kwe-PLLA kunye ne-Ec, kunye nobukhulu beenkozo kunye ne-crystallinity ye-PLLA yehla, enokuthi ngenxa yokuba i-EC ihambelana ngokuyinxenye kunye ne-PLLA ukwenza i-amorphous structure, ngaloo ndlela inciphisa ingqibelelo ye-crystal structure yomxube. Iziphumo ze-X-ray diffraction ze-PLLA-MC nazo zibonisa iziphumo ezifanayo. I-X-ray diffraction curve ibonisa umphumo womlinganiselo we-PLLA / cellulose ether kwisakhiwo somxube, kwaye iziphumo zihambelana ngokupheleleyo neziphumo ze-FT-IR kunye ne-DSC.
3. Isiphelo
Inkqubo yokuxuba ye-poly-L-lactic acid kunye ne-cellulose ether (i-ethyl cellulose kunye ne-methyl cellulose) yafundwa apha. Ukuhambelana kwamacandelo amabini kwinkqubo yokuxuba kwafundwa nge-FT-IR, i-XRD kunye ne-DSC. Iziphumo zibonise ukuba i-hydrogen bonding ikhona phakathi kwe-PLLA kunye ne-cellulose ether, kwaye amacandelo amabini kwinkqubo ayehambelana ngokuyinxenye. Ukuncipha kwe-PLLA / i-cellulose ether ratio kubangela ukuhla kwe-melting point, i-crystallinity, kunye ne-crystal integrity ye-PLLA kwi-blend, okubangelwa ukulungiswa kweengxube ze-crystallinity ezahlukeneyo. Ngoko ke, i-cellulose ether ingasetyenziselwa ukuguqula i-poly-L-lactic acid, eya kudibanisa ukusebenza kakuhle kwe-polylactic acid kunye nexabiso eliphantsi le-cellulose ether, ehambelana nokulungiswa kwezinto ezichithwa ngokupheleleyo ze-polymer.
Ixesha lokuposa: Jan-13-2023