1. Intshayelelo
Okwangoku, eyona nto iphambili ekrwada esetyenziswa ekulungiselelenii-cellulose etherngumqhaphu, kwaye imveliso yawo iyehla, kwaye ixabiso nalo liyenyuka;
Ngaphezu koko, i-etherifying agents ezisetyenziswa ngokuqhelekileyo ezifana ne-chloroacetic acid (ityhefu ephezulu) kunye ne-ethylene oxide (i-carcinogenic) nazo ziyingozi kakhulu kumzimba womntu kunye nokusingqongileyo. Incwadi
Kwesi sahluko, i-pine cellulose kunye nokuhlambuluka okungaphezulu kwe-90% ekhutshwe kwisahluko sesibini isetyenziswe njengento eluhlaza, kunye ne-sodium chloroacetate kunye ne-2-chloroethanol isetyenziswa njengeendawo.
Ukusebenzisa i-chloroacetic acid enetyhefu kakhulu njenge-etherifying agent, i-anionicI-carboxymethyl cellulose (CMC), i-cellulose engekho ionic ye-hydroxyethyl yalungiswa.
I-Cellulose (HEC) kunye ne-hydroxyethyl carboxymethyl cellulose (HECMC) ezintathu ze-cellulose ethers. into enye
Ubuchule bokulungiselela ii-ethers ezintathu ze-cellulose zaphuculwa ngokusetyenziswa kovavanyo kunye novavanyo lwe-orthogonal, kunye ne-synthesized cellulose ethers zibonakaliswe yi-FT-IR, XRD, H-NMR, njl.
Izinto ezisisiseko ze-cellulose etherification
Umgaqo we-cellulose etherification unokwahlulwa ube ngamacandelo amabini. Inxalenye yokuqala yinkqubo ye-alkalization, oko kukuthi, ngexesha le-alkalization reaction of cellulose,
Ihlakazekile ngokulinganayo kwisisombululo se-NaOH, i-pine cellulose idumba ngamandla phantsi kwesenzo sokuvuselela oomatshini, kunye nokwandiswa kwamanzi.
Isixa esikhulu seemolekyuli ezincinci ze-NaOH zangena ngaphakathi kwi-pine cellulose, kwaye zasabela kunye namaqela e-hydroxyl kwiringi yeyunithi yesakhiwo seglucose,
Ivelisa i-alkali cellulose, iziko elisebenzayo le-etherification reaction.
Inxalenye yesibini yinkqubo ye-etherification, oko kukuthi, ukusabela phakathi kweziko elisebenzayo kunye ne-sodium chloroacetate okanye i-2-chloroethanol phantsi kweemeko ze-alkaline, okukhokelela ekubeni
Ngelo xesha, i-etherifying agent sodium chloroacetate kunye ne-2-chloroethanol iya kuvelisa iqondo elithile lamanzi phantsi kweemeko ze-alkaline.
Iimpendulo zecala zisonjululwe ukuvelisa i-sodium glycolate kunye ne-ethylene glycol, ngokulandelelanayo.
2 I-alkali egxininisiweyo ye-decrystallization pretreatment yepine cellulose
Okokuqala, lungiselela ingqungquthela ethile yesisombululo se-NaOH ngamanzi adibeneyo. Emva koko, kwiqondo lokushisa elithile, i-2g ye-pine fiber
I-vitamin ichithwa kumthamo othile wesisombululo se-NaOH, ixutywe ixesha elithile, ize ihlulwe ukuze isetyenziswe.
Umenzi woMfanekiso weSixhobo
Ukuchaneka kwe-pH Meter
Umqokeleli uhlobo lobushushu rhoqo ukufudumeza magnetic stirrer
I-oven yokucoca i-vacuum
Ibhalansi ye-elektroniki
Uhlobo lwamanzi olujikelezayo lwempompo yevacuum eneenjongo ezininzi
I-Fourier Transform Infrared Spectrometer
X-reyi diffractometer
I-Nuclear Magnetic Resonance Spectrometer
Hangzhou Aolilong Instrument Co., Ltd.
IHangzhou Huichuang Instrument Equipment Co., Ltd.
Shanghai Jinghong Experimental Equipment Co., Ltd.
METTLER TOLEDO Instruments (Shanghai) Co., Ltd.
IHangzhou David Science and Education Instrument Co., Ltd.
IAmerican Thermo Fisher Co., Ltd.
American Thermoelectric Switzerland ARL Inkampani
Inkampani yaseSwitzerland iBRUKER
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Ukulungiswa kwee-CMCs
Ukusebenzisa i-alkali wood cellulose eyenziwe yi-alkali decrystallization egxininisiweyo njengezinto ezikrwada, kusetyenziswa i-ethanol njengesinyibilikisi kunye nokusetyenziswa kwe-sodium chloroacetate njenge-etherification.
I-CMC ene-DS ephezulu yalungiswa ngokudibanisa i-alkali kabini kunye ne-agent etherifying kabini. Yongeza i-2g yomthi we-alkali cellulose kwi-flask enentamo ezine, uze wongeze umthamo othile we-ethanol solvent, kwaye uvuselele kakuhle i-30min.
malunga, ukuze i-alkali cellulose ihlakazwe ngokupheleleyo. Emva koko yongeza inani elithile le-alkali ye-alkali kunye ne-sodium chloroacetate ukusabela ixesha elithile kwiqondo lokushisa elithile le-etherification.
Emva kwexesha, ukongezwa kwesibini kwe-alkaline agent kunye ne-sodium chloroacetate elandelwa yi-etherification ixesha elithile. Emva kokuba impendulo iphelile, pholisa kwaye upholise, ngoko
Ungathathi hlangothi ngesixa esifanelekileyo se-acetic acid, emva koko isihluzo sokufunxa, hlamba kwaye womise.
Ukulungiswa kwee-HECs
Ukusebenzisa i-alkali wood cellulose pretreated ne-alkali decrystallization egxininiswe njengezinto eziluhlaza, i-ethanol njengesinyibilikisi kunye ne-2-chloroethanol njenge-etherification.
I-HEC ene-MS ephezulu yalungiswa ngokongeza i-alkali kabini kunye ne-etherifying agent kabini. Yongeza i-2g yomthi we-alkali cellulose kwi-flask enentamo ezine, kwaye wongeze umthamo othile we-90% (iqhekeza levolumu) i-ethanol,
Gxuma ixesha elithile ukuze usasaze ngokupheleleyo, emva koko wongeze inani elithile le-alkali, kwaye ushushu ngokukhawuleza, yongeza umthamo othile we-2-
I-Chloroethanol, i-etherified kwiqondo lokushisa rhoqo ixesha elithile, kwaye yongeza i-sodium hydroxide eseleyo kunye ne-2-chloroethanol ukuze iqhube i-etherification ixesha elithile. phatha
Emva kokuba impendulo igqityiwe, nciphisa ngexabiso elithile le-acetic acid, kwaye ekugqibeleni ucofe ngesihluzo seglasi (G3), hlamba, kwaye wome.
Ukulungiswa kweHEMCC
Ukusebenzisa i-HEC elungiselelwe kwi-3.2.3.4 njengento eluhlaza, i-ethanol njenge-reaction medium, kunye ne-sodium chloroacetate njenge-ejenti etherifying ukulungiselela.
I-HECMC. Inkqubo ethile yile: thatha inani elithile le-HEC, uyibeke kwi-100 mL yeflask enentamo ezine, kwaye wongeze inani elithile lomthamo.
I-90% ye-ethanol, inyakaziswa ngoomatshini kangangexesha elithile ukuze isasazeke ngokupheleleyo, yongeza umlinganiselo othile wealkali emva kokufudumeza, kwaye kancinane wongeze.
I-sodium chloroacetate, i-etherification kwiqondo lokushisa elingaguqukiyo liphela emva kwexesha elithile. Emva kokuba impendulo igqityiwe, yinciphise nge glacial acetic acid ukuyinciphisa, emva koko sebenzisa isihluzo seglasi (G3)
Emva kokucoca ukufunxa, ukuhlamba kunye nokomisa.
Ukuhlanjululwa kwe-cellulose ethers
Kwinkqubo yokulungiswa kwe-cellulose ether, ezinye iimveliso zihlala ziveliswa, ngakumbi ityuwa ye-sodium chloride yetyuwa kunye nezinye.
ukungcola. Ukuze kuphuculwe umgangatho we-cellulose ether, ukucocwa okulula kwenziwa kwi-ether ye-cellulose efunyenweyo. ngokuba zisemanzini
Kukho ukunyibilika okwahlukileyo, ngoko ke uvavanyo lusebenzisa iqhezu elithile lomthamo we-ethanol enamanzi ukucoca ii-ethers ezintathu ezilungiselelwe i-cellulose.
utshintsho.
Beka isampuli ye-cellulose ether elungiselelwe umgangatho othile kwibeaker, yongeza umlinganiselo othile we-80% ye-ethanol ethe yafudunyezwa yaya kutsho kuma-60 ℃ ~ 65 ℃, kwaye ugcine ukuvuselela ngoomatshini ku-60 ℃ ~ 65 ℃ kwiqondo lobushushu elingaguqukiyo lokufudumeza i-magnetic stirrer. nge 10 ℃. imiz. Thatha i-supernatant uyomise
Kwi-beaker ecocekileyo, sebenzisa i-nitrate yesilivere ukujonga i-ion chloride. Ukuba kukho imvula emhlophe, yihluze ngesihluzo seglasi kwaye uthathe okuqinileyo
Phinda kwakhona amanyathelo angaphambili kwinxalenye yomzimba, de kube i-filtrate emva kokongeza i-1 drop ye-AgNO3 isisombululo ayinayo i-precipitate emhlophe, oko kukuthi, ukuhlanjululwa kunye nokuhlamba kugqityiwe.
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kwi (ikakhulu ukususa i-reaction by-product NaCl). Emva kokucoca ukufunxa, ukomisa, ukupholisa kwiqondo lokushisa kunye nokulinganisa.
ubunzima, g.
Iindlela zoVavanyo kunye neempawu zeCellulose Ethers
Ukumiselwa kwesiDanga sokuTshintshela (DS) kunye nesiDanga seMolar sokuTshintsha (MS)
Ukumiselwa kwe-DS: Okokuqala, linganisa i-0.2 g (echanekile ukuya kwi-0.1 mg) yesampuli ye-ether ecocekileyo neyomisiweyo, yinyibilikise
I-80mL yamanzi adibeneyo, axutywe kwindawo yokuhlambela amanzi ashushu rhoqo kwi-30 ℃ ~ 40 ℃ ye-10min. Emva koko lungisa isisombululo se-sulfuric acid okanye isisombululo se-NaOH
i-pH yesisombululo de i-pH yesisombululo ibe yi-8. Emva koko kwi-beaker efakwe i-electrode yemitha ye-pH, sebenzisa isisombululo esiqhelekileyo se-asidi ye-sulfuric.
Ukuthoba, phantsi kweemeko ezikhuthazayo, jonga ukufundwa kwemitha ye-pH ngelixa i-titrating, xa ixabiso le-pH lesisombululo lihlengahlengiswa libe yi-3.74,
I-titration iyaphela. Qaphela umthamo wesisombululo esiqhelekileyo se-sulfuric acid esetyenziswayo ngeli xesha.
Isizukulwana:
Isixa samanani aphezulu eproton kunye neqela le-hydroxyethyl
Umlinganiselo wenani leeprotoni eziphezulu; I7 bubunzima beqela le-methylene kwiqela le-hydroxyethyl
Ubunzulu bencopho yeproton resonance; Ubunzulu beproton resonance peak yamaqela e-5 methine kunye neqela elinye le-methylene kwiyunithi ye-glucose ye-cellulose.
Isishwankathelo.
Iindlela zovavanyo ezichazwe kuvavanyo lwe-infrared ye-cellulose ethers CMC, HEC kunye ne-HEECMC
Umthetho
3.2.4.3 Uvavanyo lwe-XRD
I-X-ray Diffraction Analysis Testing Characterization Test of Three Cellulose Ethers CMC, HEC and HEECMC
indlela yovavanyo echaziweyo.
3.2.4.4 Uvavanyo lwe-H-NMR
I-spectrometer ye-H NMR ye-HEC ilinganiswe nge-Avance400 H NMR i-spectrometer eveliswe yi-BRUKER.
Ukusebenzisa i-deuterated dimethyl sulfoxide njenge-solvent, isisombululo savavanywa ngolwelo lwe-hydrogen NMR spectroscopy. Uvavanyo oluphindaphindiweyo lwaluyi-75.5MHz.
Ukufudumala, isisombululo ngu-0.5mL.
3.3 Iziphumo kunye noHlahlelo
3.3.1 Ukuphucula inkqubo yamalungiselelo eCMC
Ukusebenzisa i-pine cellulose ekhutshwe kwisahluko sesibini njengento ekrwada, kunye nokusetyenziswa kwe-sodium chloroacetate njenge-agent etherifying, indlela yokuvavanya into enye yamkelwa,
Inkqubo yokulungiselela i-CMC yaphuculwa, kwaye iinguqu zokuqala zovavanyo zibekwe njengoko kuboniswe kwiThebhile 3.3. Oku kulandelayo yinkqubo yokulungiselela i-HEC
Kubugcisa, uhlalutyo lwezinto ezahlukeneyo.
Itheyibhile 3.3 IiNqobo zeFactor yokuQala
Factor Ixabiso lokuqala
Unyango lwangaphambili lobushushu bealkalizing/℃ 40
Unyango lwangaphambili lwe-alkalizing ixesha/h 1
Pretreatment umlinganiselo oqinileyo-ulwelo/(g/mL) 1:25
Uxinzelelo lwe-lye yangaphambi konyango/% 40
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Inqanaba lokuqala lobushushu be-etherification/℃ 45
Ixesha lokuqala le-etherification/h 1
Inqanaba lesibini le-etherification lobushushu/℃ 70
Ixesha le-etherification yenqanaba lesibini/h 1
Isiseko sedosi kwinqanaba le-etherification/g 2
Isixa se-etherifying agent kwinqanaba le-etherification/g 4.3
I-Etherified solid-liquid ratio/(g/mL) 1:15
3.3.1.1 Impembelelo yeemeko ezahlukeneyo kwi-CMC substitution degree kwi-pretreatment alkalization stage.
1. Isiphumo sobushushu be-alkalization yangaphambi kokunyangwa kwiqondo lokuthatha indawo ye-CMC
Ukuze kuqwalaselwe isiphumo pretreatment alkalization lobushushu kwiqondo lokutshintshwa kwi CMC efunyenweyo, kwimeko yokulungisa ezinye izinto njengoko amaxabiso okuqala,
Phantsi kweemeko, isiphumo pretreatment alkalization lobushushu kwi CMC substitution degree kuxoxiwe, kwaye iziphumo ziboniswe Fig.
Unyango lwangaphambili lobushushu bealkalizing/℃
Isiphumo sokunyangwa kweqondo lobushushu lealkalizing kwidigri yeCMC endaweni
Ingabonwa ukuba iqondo lokutshintshwa kwe-CMC liyenyuka ngokunyuka kobushushu be-alkalization yangaphambi kokunyangwa, kunye nobushushu be-alkalization yi-30 °C.
Izidanga ezingentla zokutshintsha ziyancipha ngokunyuka kwamaqondo obushushu. Oku kungenxa yokuba ubushushu be-alkalizing buphantsi kakhulu, kwaye iimolekyuli zingasebenzi kwaye azikwazi
Ukutshabalalisa ngokufanelekileyo indawo ye-crystalline ye-cellulose, eyenza kube nzima kwi-ejenti ye-etherifying ukungena ngaphakathi kwe-cellulose kwinqanaba le-etherification, kwaye iqondo lokuphendula liphezulu.
ephantsi, ekhokelela kwiqondo eliphantsi lokutshintshwa kwemveliso. Nangona kunjalo, ubushushu be-alkalization akufanele bube phezulu kakhulu. Njengoko ubushushu bukhula, phantsi kwesenzo sobushushu obuphezulu kunye ne-alkali enamandla,
I-Cellulose ithanda ukuthotywa kwe-oxidative, kwaye iqondo lokutshintshwa kwemveliso ye-CMC liyehla.
2. Impembelelo yexesha lokunyangwa kwealkalinization kwiCMC substitution degree
Phantsi kwemeko yokuba iqondo lobushushu pretreatment alkalization 30 °C kunye nezinye izinto amaxabiso okuqala, isiphumo pretreatment alkalization ixesha kwi CMC kuxoxwe.
Isiphumo sokutshintshwa. Isidanga sokutshintsha
Unyango lwangaphambili lwe-alkalizing ixesha/h
Isiphumo sokunyangwa kwangaphambili kwexesha le-alkalinizationCMCisidanga
Inkqubo ye-bulking ngokwayo iyakhawuleza, kodwa isisombululo se-alkali sifuna ixesha elithile lokusabalalisa kwifiber.
Ingabonwa ukuba xa ixesha le-alkalization liyi-0.5-1.5h, idigri yokutshintshwa kwemveliso iyanda ngokunyuka kwexesha le-alkalization.
Iqondo lokutshintshwa kwemveliso efunyenweyo yayiphezulu xa ixesha liyi-1.5h, kwaye iqondo lokutshintshwa liyancipha ngokunyuka kwexesha emva kwe-1.5h. Oku kunako
Kungenzeka ukuba ekuqaleni kwe-alkalization, kunye nokwandiswa kwexesha le-alkalization, ukungena kwe-alkali kwi-cellulose kukwanele, ukwenzela ukuba i-fiber.
Isakhiwo esiphambili sikhululekile ngakumbi, ukwandisa i-agent etherifying kunye ne-medium medium
Ixesha lokuposa: Apr-26-2024