A na-edozi ihe ngwọta ngwakọta nke poly-L-lactic acid na ethyl cellulose na chloroform na ngwọta ngwakọta nke PLLA na methyl cellulose na trifluoroacetic acid, a kwadebere ngwakọta PLLA / cellulose ether site na nkedo; Ejikọtara ngwakọta ndị enwetara site na akwụkwọ mgbanwe infrared spectroscopy (FT-IR), calorimetry scanning dị iche (DSC) na diffraction X-ray (XRD). Enwere njikọ hydrogen n'etiti PLLA na cellulose ether, akụkụ abụọ ahụ dakọtara n'otu akụkụ. Site na mmụba nke cellulose ether ọdịnaya na ngwakọta, ebe mgbaze, crystallinity na kristal iguzosi ike n'ezi ihe nke ngwakọta ga-ebelata. Mgbe ọdịnaya MC dị elu karịa 30%, enwere ike ịnweta ngwakọta amorphous. Ya mere, ether cellulose nwere ike iji gbanwee poly-L-lactic acid iji kwadebe ihe polymer na-emebi emebi nwere ihe dị iche iche.
isiokwu: poly-L-lactic acid, ethyl cellulose,methyl cellulose, ngwakọta, cellulose ether
Mmepe na ntinye nke polymers eke na ihe polymer synthetic na-emebi emebi ga-enyere aka dozie nsogbu gburugburu ebe obibi na nsogbu akụ na ụba nke ụmụ mmadụ chere ihu. N'afọ ndị na-adịbeghị anya, nchọpụta banyere njikọ nke ihe ndị na-emepụta ihe na-emepụta ihe na-emepụta ihe na-emepụta ihe na-eji ihe ndị a na-emegharị emeghari dị ka ihe ndị na-emepụta polymer adọtala nlebara anya zuru ụwa ọnụ. Polylactic acid bụ otu n'ime polyester aliphatic dị mkpa na-emebi emebi. Enwere ike imepụta lactic acid site na gbaa ụka nke ihe ọkụkụ (dịka ọka, poteto, sucrose, wdg), yana microorganisms nwekwara ike mebie ya. Ọ bụ akụrụngwa enwere ike imeghari. A na-akwado polylactic acid site na lactic acid site na polycondensation kpọmkwem ma ọ bụ polymerization na-emepe mgbanaka. Ngwaahịa ikpeazụ nke mmebi ya bụ lactic acid, nke na-agaghị emetọ gburugburu ebe obibi. PIA nwere ezigbo ihe eji arụ ọrụ, nhazi nhazi, biodegradability na biocompatibility. Ya mere, PLA ọ bụghị nanị na ọ nwere ọtụtụ ngwa dị iche iche n'ọhịa nke injinia biomedical, kamakwa ọ nwere nnukwu ahịa nwere ike ime n'ọhịa nke mkpuchi, plastik, na textiles.
Ọnụ ego dị elu nke poly-L-lactic acid na ntụpọ arụmọrụ ya dị ka hydrophobicity na brittleness na-amachi oke ngwa ya. Iji belata ọnụ ahịa ya ma melite arụmọrụ PLLA, nkwadebe, ndakọrịta, morphology, biodegradability, mechanical properties, hydrophilic / hydrophobic itule na ngwa ngwa nke polylactic acid copolymers na ngwakọta amụwo nke ọma. N'ime ha, PLLA na-etolite ngwakọta dakọtara na poly DL-lactic acid, polyethylene oxide, polyvinyl acetate, polyethylene glycol, wdg. na okike. Ihe ndị na-emepụta cellulose bụ ihe mbụ polymer eke sitere n'okike nke mmadụ mepụtara, nke kachasị mkpa bụ cellulose ethers na cellulose esters. M. Nagata et al. mụọ usoro ngwakọta PLLA/cellulose wee chọpụta na akụkụ abụọ ahụ adabaghị, mana kristal na-emebi emebi nke PLLA nwere mmetụta dị ukwuu site na akụkụ cellulose. N. Ogata et al mụọ ọrụ na nhazi nke PLLA na cellulose acetate mix system. Patent ndị Japan mụọkwara biodegradability nke PLLA na ngwakọta nitrocellulose. Y. Teramoto et al mụrụ nkwadebe, ihe ọkụ na akụrụngwa nke PLLA na cellulose diacetate graft copolymers. Ka ọ dị ugbu a, enwere ọmụmụ ole na ole gbasara usoro ngwakọta nke polylactic acid na cellulose ether.
N'ime afọ ndị na-adịbeghị anya, ndị otu anyị etinyela aka na nyocha nke copolymerization ozugbo na mgbanwe mgbanwe nke polylactic acid na polymers ndị ọzọ. Iji jikọta ihe ndị dị mma nke polylactic acid na ọnụ ala dị ala nke cellulose na ihe ndị na-emepụta ya iji kwadebe ihe ndị na-emepụta ihe na-emepụta ihe na-emepụta ihe na-emepụta ihe, anyị na-ahọrọ cellulose (ether) dị ka ihe a gbanwere maka mgbanwe mgbanwe. Ethyl cellulose na methyl cellulose bụ ihe abụọ dị mkpa cellulose ethers. Ethyl cellulose bụ mmiri na-adịghị edozi mmiri na-abụghị ionic cellulose alkyl ether, nke a pụrụ iji mee ihe dị ka ihe ahụike, plastik, nrapado na ndị na-emecha akwa ákwà. Methyl cellulose bụ mmiri soluble, nwere ezigbo mmiri mmiri, ịdị n'otu, njide mmiri na ihe ndị na-emepụta ihe nkiri, a na-ejikwa ya n'ọhịa nke ihe owuwu ụlọ, mkpuchi, ihe ịchọ mma, ọgwụ na akwụkwọ. N'ebe a, a kwadebere ngwakọta PLLA / EC na PLLA / MC site na usoro nkedo ngwọta, na ndakọrịta, ihe ọkụ ọkụ na njirimara crystallization nke PLLA / cellulose ether ngwakọta a tụlere.
1. Akụkụ nnwale
1.1 Akụrụngwa
Ethyl cellulose (AR, Tianjin Huazhen Special Chemical Reagent Factory); methyl cellulose (MC450), sodium dihydrogen phosphate, disodium hydrogen phosphate, ethyl acetate, stannous isooctanoate, chloroform (nke dị n'elu bụ niile ngwaahịa nke Shanghai Chemical Reagent Co., Ltd., na ịdị ọcha bụ AR ọkwa); L-lactic acid (ọkwa ọgwụ, ụlọ ọrụ PURAC).
1.2 Nkwadebe nke ngwakọta
1.2.1 Nkwadebe nke polylactic acid
A kwadebere Poly-L-lactic acid site na usoro polycondensation kpọmkwem. Tulee ngwọta mmiri L-lactic acid nke nwere akụkụ dị nta nke 90% wee gbakwunye ya na flask olu atọ, dehydrate na 150 ° C maka awa 2 n'okpuru nrụgide nkịtị, wee meghachi omume maka awa 2 n'okpuru nrụgide agụụ nke 13300Pa, n'ikpeazụkwa. meghachi omume maka awa 4 n'okpuru oghere nke 3900Pa iji nweta ihe prepolymer akpọnwụwo nkụ. Ngụkọta ego nke mmiri mmiri lactic acid na-ewepụ ihe mmepụta mmiri bụ mkpokọta prepolymer. Gbakwunye chloride stannous (obere akụkụ bụ 0.4%) na p-toluenesulfonic acid (oke nke stannous chloride na p-toluenesulfonic acid bụ 1/1 molar ratio) usoro ihe na-akpata na prepolymer enwetara, na na condensation, etinyere sieves molecular na tube. iji nweta obere mmiri, a na-echekwa ihe na-akpali akpali. A na-emeghachi usoro ahụ dum na oghere nke 1300 Pa na okpomọkụ nke 150 ° C. maka awa 16 iji nweta polymer. Gbanyụọ polymer enwetara na chloroform iji dozie ngwọta 5%, nzacha ma wụsa ya na ether anhydrous maka awa 24, kpochaa ntụ ntụ, tinye ya na oven -0.1MPa na-ekpo ọkụ na 60 ° C maka awa 10 ruo 20 iji nweta Ọcha akọrọ. PLLA polymer. Achọpụtara ịdị arọ molekụla nke PLLA nwetara ka ọ bụrụ 45000-58000 Daltons site na chromatography mmiri na-arụ ọrụ dị elu (GPC). A na-edobe ihe nlele n'ime ihe nchacha nwere phosphorus pentoxide.
1.2.2 Nkwadebe nke ngwakọta polylactic acid-ethyl cellulose (PLLA-EC)
Tulee ego a chọrọ nke poly-L-lactic acid na ethyl cellulose iji mee 1% chloroform ngwọta n'otu n'otu, wee dozie ngwọta agwakọta PLLA-EC. Oke PLLA-EC agwakọta ngwọta bụ: 100/0, 80/20, 60/40, 40/60, 20/80, 0/l00, nke mbụ nọmba na-anọchi anya ọnụ ọgụgụ dị nta nke PLLA, na nke ikpeazụ nọmba na-anọchi anya oke nke EC Fraction. A na-eji igwe magnetik kpalie ihe ngwọta ndị a kwadebere maka awa 1-2, wee wụsa ya n'ime efere iko iji mee ka chloroform pụta n'onwe ya iji mepụta ihe nkiri. Mgbe emechara ihe nkiri ahụ, a na-etinye ya na oven na-ekpo ọkụ ka ọ kpọọ nkụ na obere okpomọkụ maka awa 10 iji wepụ chloroform kpamkpam na fim ahụ. . Ngwọta ngwakọta na-enweghị agba na nke doro anya, na ihe nkiri ngwakọta na-enweghịkwa ụcha na nghọta. A kpochara ngwakọta a ma chekwaa ya n'ebe a na-ekpochapụ ihe maka iji mechaa.
1.2.3 Nkwadebe nke ngwakọta polylactic acid-methylcellulose (PLLA-MC)
Tulee ego achọrọ nke poly-L-lactic acid na methyl cellulose iji mee 1% trifluoroacetic acid ngwọta n'otu n'otu. A kwadebere ihe nkiri ngwakọta PLLA-MC site n'otu usoro dị ka ihe nkiri ngwakọta PLLA-EC. A kpochara ngwakọta a ma chekwaa ya n'ebe a na-ekpochapụ ihe maka iji mechaa.
1.3 Nnwale arụmọrụ
MANMNA IR-550 infrared spectrometer (Nicolet.Corp) tụrụ ụdịdị dị iche iche infrared nke polymer (mbadamba KBr). A na-eji DSC2901 di iche iche scanning calorimeter (TA ụlọ ọrụ) tụọ akụkụ DSC nke ihe nlele ahụ, ọnụego kpo oku bụ 5 Celsius C / min, a na-atụkwa iko mgbanwe okpomọkụ, ebe mgbaze na crystallinity nke polymer. Jiri Rigaku. A na-eji D-MAX/Rb diffractometer nwalee usoro mgbasa ozi X-ray nke polymer iji mụọ njirimara crystallization nke sample.
2. Nsonaazụ na mkparịta ụka
2.1 Nnyocha spectroscopy infrared
Fourier transform infrared spectroscopy (FT-IR) nwere ike mụọ mmekọrịta dị n'etiti ihe ngwakọta nke ngwakọta site n'echiche nke ọkwa molekụla. Ọ bụrụ na abụọ homopolymers dakọtara, mgbanwe na ugboro ugboro, mgbanwe na ike, na ọbụna ọdịdị ma ọ bụ na-apụ n'anya nke elu àgwà nke components nwere ike ịhụ. Ọ bụrụ na abụọ homopolymers adịghị dakọtara, ụdịdị dị iche iche nke ngwakọta bụ nnọọ superposition nke homopolymer abụọ. Na ụdịdị dị iche iche PLLA, enwere oke ịma jijiji na-agbatị C = 0 na 1755cm-1, ọnụ ọgụgụ na-adịghị ike na 2880cm-1 kpatara C-H na-agbatị vibration nke methine otu, yana nnukwu band na 3500 cm-1 bụ. kpatara site na njedebe hydroxyl otu. Na EC ụdịdị dị iche iche, njirimara ọnụ ọgụgụ dị na 3483 cm-1 bụ OH na-agbatị elu vibration elu, na-egosi na e nwere O-H otu fọdụrụ na molekụla yinye, ebe 2876-2978 cm-1 bụ C2H5 na-agbatị elu vibration elu, na 1637 cm-1 bụ HOH na-ehulata ọnụ ọgụgụ kacha elu (nke mere na mmiri na-amịpụta ihe). Mgbe agwakọta PLLA na EC, na ụdị IR nke mpaghara hydroxyl nke ngwakọta PLLA-EC, ọnụ ọgụgụ O-H na-agbanwe gaa na ọnụọgụ ebili mmiri dị ala yana mmụba nke ọdịnaya EC, wee rute nke kacha nta mgbe PLLA/EC bụ 40/60 wavenumber, wee gbanwee gaa na ebili mmiri dị elu, na-egosi na mmekọrịta dị n'etiti PUA na 0-H nke EC dị mgbagwoju anya. Na mpaghara C = O vibration nke 1758cm-1, C = 0 ọnụ ọgụgụ kasị elu nke PLLA-EC gbanwetụrụ na ọnụ ọgụgụ ebili mmiri dị ala na mmụba nke EC, nke gosipụtara na mmekọrịta dị n'etiti C = O na OH nke EC adịghị ike.
Na spectrogram nke methylcellulose, njirimara kacha elu na 3480cm-1 bụ O-H na-agbatị ọnụ ọnụ, ya bụ, e nwere ndị fọdụrụ O-H dị na MC molecular yinye, na HOH na-ehulata ọnụ elu elu dị na 1637cm-1. na MC ruru EC bụ ihe hygroscopic karịa. Dị ka usoro ngwakọta PLLA-EC, na infrared spectra nke mpaghara hydroxyl nke ngwakọta PLLA-EC, ọnụ ọgụgụ O-H na-agbanwe site na mmụba nke ọdịnaya MC, ma nwee ọnụ ọgụgụ kacha nta mgbe PLLA/MC dị. 70/30. Na mpaghara ịma jijiji C = O (1758 cm-1), ọnụ ọgụgụ C = O na-agbanwe ntakịrị na ọnụọgụ ebili mmiri na mgbakwunye nke MC. Dị ka anyị kwuru na mbụ, e nwere ọtụtụ ìgwè dị na PLLA nwere ike ịmepụta mmekọrịta pụrụ iche na ndị polymers ndị ọzọ, na nsonaazụ nke infrared spectrum nwere ike ịbụ mmetụta jikọtara ọnụ nke ọtụtụ mmekọrịta pụrụ iche nwere ike ime. N'ime usoro ngwakọta nke PLLA na cellulose ether, enwere ike ịnwe ụdị njikọ hydrogen dị iche iche n'etiti otu ester nke PLLA, otu njedebe hydroxyl na ether otu cellulose ether (EC ma ọ bụ MG), na ndị fọdụrụ hydroxyl otu. PLLA na EC ma ọ bụ MC nwere ike dakọtara akụkụ ụfọdụ. O nwere ike ịbụ n'ihi ịdị adị na ike nke ọtụtụ njikọ hydrogen, ya mere mgbanwe ndị dị na mpaghara O-H dị ịrịba ama karị. Otú ọ dị, n'ihi mgbochi siri ike nke otu cellulose, njikọ hydrogen n'etiti C = O otu nke PLLA na O-H otu cellulose ether adịghị ike.
2.2 nyocha DSC
Usoro DSC nke ngwakọta PLLA, EC na PLLA-EC. The iko mgbanwe okpomọkụ Tg nke PLLA bụ 56.2°C, kristal agbaze okpomọkụ Tm bụ 174.3°C, na crystallinity bụ 55.7%. EC bụ polymer amorphous nwere Tg nke 43 Celsius na enweghị okpomọkụ na-agbaze. Tg nke akụkụ abụọ nke PLLA na EC dị ezigbo nso, na mpaghara mgbanwe abụọ na-agafe na enweghị ike ịmata ya, n'ihi ya, ọ na-esiri ike iji ya dị ka njirimara maka ndakọrịta usoro. Site na mmụba nke EC, Tm nke ngwakọta PLLA-EC belatara ntakịrị, na crystallinity belatara (kristal nke sample na PLLA/EC 20/80 bụ 21.3%). Tm nke ngwakọta ahụ belatara site na mmụba nke ọdịnaya MC. Mgbe PLLA/MC dị ala karịa 70/30, Tm nke ngwakọta na-esiri ike ịlele, ya bụ, ihe fọrọ nke nta ka ọ bụrụ ngwakọta amorphous nwere ike nweta. Mbelata nke ebe mgbaze nke ngwakọta nke polymers crystalline na amorphous polymers na-abụkarị n'ihi ihe abụọ kpatara ya, otu bụ mmetụta dilution nke akụkụ amorphous; nke ọzọ nwere ike ịbụ mmetụta nhazi dị ka mbelata nke izu oke kristal ma ọ bụ nha kristal nke polymer crystalline. Nsonaazụ nke DSC gosiri na n'ime usoro ngwakọta nke PLLA na cellulose ether, akụkụ abụọ ahụ na-adaba n'otu akụkụ, a na-egbochi usoro crystallization nke PLLA na ngwakọta, na-eme ka mbelata nke Tm, crystallinity na crystal size nke PLLA. Nke a na-egosi na ndakọrịta akụkụ abụọ nke usoro PLLA-MC nwere ike ịdị mma karịa nke usoro PLLA-EC.
2.3 X-ray diffraction
Usoro XRD nke PLLA nwere ọnụ ọgụgụ kachasị ike na 2θ nke 16.64 °, nke kwekọrọ na ụgbọ elu kristal 020, ebe elu na 2θ nke 14.90 °, 19.21 ° na 22.45 ° kwekọrọ na 101,023, na kristal 121. Elu, ya bụ, PLLA bụ nhazi α-crystalline. Otú ọ dị, ọ dịghị ihe owuwu ihe owuwu kristal dị n'akụkụ mgbagwoju anya nke EC, nke na-egosi na ọ bụ nhazi amorphous. Mgbe agwakọtara PLLA na EC, ọnụ ọgụgụ kasị elu dị na 16.64° ji nwayọọ nwayọọ gbasaa, ike ya na-esiwanye ike, ọ kwagara ntakịrị gaa n'akụkụ dị ala. Mgbe ọdịnaya EC bụ 60%, ọnụ ọgụgụ kristal agbasawo. Ọnụ ọgụgụ dị warara x-ray dị warara na-egosi ịdị elu kristal na oke ọka buru ibu. Ka ọnụ ọgụgụ kasị elu nke diffraction na-abawanye, ka nha ọka na-adị ntakịrị. Ngbanwe nke elu diffraction na nkuku dị ala na-egosi na oghere ọka na-abawanye, ya bụ, iguzosi ike n'ezi ihe nke kristal na-ebelata. Enwere njikọ hydrogen n'etiti PLLA na EC, na nha ọka na kristal nke PLLA na-ebelata, nke nwere ike ịbụ n'ihi na EC dakọtara na PLLA n'akụkụ ụfọdụ iji mepụta usoro amorphous, si otú ahụ na-ebelata iguzosi ike n'ezi ihe nke nhazi kristal nke ngwakọta. Nsonaazụ mgbasa ozi X-ray nke PLLA-MC na-egosipụtakwa nsonaazụ yiri ya. Usoro ntụgharị X-ray na-egosipụta mmetụta nke oke PLLA / cellulose ether na nhazi nke ngwakọta, na nsonaazụ ya na-adabere kpamkpam na nsonaazụ FT-IR na DSC.
3. Nkwubi okwu
A mụrụ usoro ngwakọta nke poly-L-lactic acid na cellulose ether (ethyl cellulose na methyl cellulose) ebe a. A mụrụ ndakọrịta nke ihe abụọ ahụ na usoro ngwakọta site na FT-IR, XRD na DSC. Nsonaazụ gosiri na njikọ hydrogen dị n'etiti PLLA na cellulose ether, na akụkụ abụọ dị na sistemụ ahụ dakọtara n'otu akụkụ. Mbelata nke PLLA/cellulose ether ratio na-ebute mbelata nke ebe mgbaze, kristal, na iguzosi ike n'ezi ihe nke PLLA na ngwakọta, na-ebute nkwadebe nke ngwakọta nke kristal dị iche iche. Ya mere, ether cellulose nwere ike iji gbanwee poly-L-lactic acid, nke ga-ejikọta ọrụ dị mma nke polylactic acid na ọnụ ala cellulose ether, nke na-eme ka nkwadebe nke ihe ndị na-emepụta ihe na-emepụta ihe na-emepụta ihe na-emepụta ihe.
Oge nzipu: Jan-13-2023