Ukulungiswa kwe-hydroxyethyl cellulose

I-Hydroxyethyl cellulose (HEC) i-non-ionic, i-polymer e-soluble yamanzi ephuma kwi-cellulose, i-polymer yendalo efumaneka kwiindonga zeeseli zezityalo. Isetyenziswa kakhulu kumashishini ahlukeneyo, kubandakanya amayeza, izinto zokuthambisa, iipeyinti, kunye nezinto zokuncamathelisa, ngenxa yokuqina kwayo okugqwesileyo, ukwenza ifilim, kunye neempawu zerheological. Ukulungiswa kwe-hydroxyethyl cellulose kubandakanya i-etherification ye-cellulose kunye ne-ethylene oxide phantsi kweemeko ze-alkaline. Le nkqubo inokwahlulwa ibe ngamanyathelo abalulekileyo: ukucocwa kwe-cellulose, i-alkalization, i-etherification, i-neutralization, ukuhlamba kunye nokomisa.

1. Ukucoca iSelulosi
Isinyathelo sokuqala ekulungiseleleni i-hydroxyethyl cellulose kukucocwa kwe-cellulose, ngokuqhelekileyo ifunyenwe kwi-pulp yomthi okanye i-cotton linters. I-cellulose eluhlaza iqulethe ukungcola okufana ne-lignin, i-hemicellulose, kunye nezinye izinto ezicatshulwayo ekufuneka zisuswe ukuze kufumaneke i-high-purity cellulose efanelekileyo ukuguqulwa kweekhemikhali.

Amanyathelo abandakanyekayo:

I-Mechanical Processing: I-cellulose ekrwada icutshungulwa ngoomatshini ukunciphisa ubungakanani bayo kwaye yandise indawo yayo, iququzelele unyango lwamachiza olulandelayo.
Unyango lweMichiza: I-cellulose iphathwa ngeekhemikhali ezifana ne-sodium hydroxide (NaOH) kunye ne-sodium sulfite (Na2SO3) ukudiliza i-lignin kunye ne-hemicellulose, ilandelwa kukuhlamba kunye ne-bleaching ukususa ukungcola okushiyekileyo kunye nokufumana i-cellulose emhlophe, ene-fibrous.

2. Ialkalization
Iselulosi esulungekileyo iye ifakwe ialkali ukuze isebenze ukwenzela ukusabela kwe-etherification. Oku kubandakanya ukunyanga i-cellulose ngesisombululo esimanzi se-sodium hydroxide.

Impendulo:
ISelulosi+NaOH→Iselulosi yeAlkali

Inkqubo:

I-cellulose imisiwe emanzini, kwaye isisombululo se-sodium hydroxide siyongezwa. I-concentration ye-NaOH ngokuqhelekileyo isuka kwi-10-30%, kwaye impendulo iqhutyelwa kumaqondo okushisa phakathi kwe-20-40 ° C.
Umxube uxutywe ukuqinisekisa ukufunxa okufanayo kwe-alkali, okukhokelela ekubunjweni kwe-alkali cellulose. Oku kuphakathi kuyasebenza ngakumbi kwi-ethylene oxide, iququzelela inkqubo ye-etherification.

3. Etherification
Isinyathelo esibalulekileyo ekulungiseleleni i-hydroxyethyl cellulose yi-etherification ye-alkali cellulose kunye ne-ethylene oxide. Le mpendulo yazisa amaqela e-hydroxyethyl (-CH2CH2OH) kwi-cellulose backbone, eyenza i-soluble yamanzi.

Impendulo:
I-alkali cellulose+Ethylene oxide→I-Hydroxyethyl cellulose+NaOH

Inkqubo:

I-ethylene oxide yongezwa kwi-cellulose ye-alkali, mhlawumbi kwi-batch okanye inkqubo eqhubekayo. Ukusabela ngokuqhelekileyo kuqhutyelwa kwi-autoclave okanye i-reactor yoxinzelelo.
Iimeko zokusabela, kubandakanywa ubushushu (50-100 ° C) kunye noxinzelelo (1-5 atm), zilawulwa ngononophelo ukuze kuqinisekiswe ukutshintshwa ngokufanelekileyo kwamaqela e-hydroxyethyl. Iqondo lokutshintshwa (DS) kunye ne-molar substitution (MS) ziiparamitha ezibalulekileyo ezichaphazela iimpawu zemveliso yokugqibela.

4. Ukungathathi hlangothi
Emva kokusabela kwe-etherification, umxube uqulethe i-cellulose ye-hydroxyethyl kunye ne-residual sodium hydroxide. Isinyathelo esilandelayo si-neutralization, apho i-alkali engaphezulu iyancipha ngokusebenzisa i-asidi, ngokuqhelekileyo i-acetic acid (CH3COOH) okanye i-hydrochloric acid (HCl).

Impendulo:NaOH+HCl→NaCl+H2O

Inkqubo:

Iasidi yongezwa kancinci kumxube wokusabela phantsi kweemeko ezilawulwayo ukuphepha ubushushu obugqithisileyo kunye nokuthintela ukuthotywa kwe-hydroxyethyl cellulose.
Umxube ongathathi hlangothi uphantsi kohlengahlengiso lwe-pH ukuqinisekisa ukuba ungaphakathi koluhlu olufunekayo, ngokuqhelekileyo malunga ne-pH engathathi hlangothi (6-8).
5. Ukuhlamba
Ukulandela ukungathathi hlangothi, imveliso kufuneka ihlanjwe ukuze isuse iityuwa kunye nezinye iimveliso. Eli nyathelo libalulekile ekufumaneni i-hydroxyethyl cellulose.

Inkqubo:

Umxube wokuphendula uhlanjululwe ngamanzi, kwaye i-cellulose ye-hydroxyethyl ihlukaniswe ngokucoca okanye i-centrifugation.
I-cellulose ye-hydroxyethyl ehlukeneyo ihlanjwa ngokuphindaphindiweyo ngamanzi adibeneyo ukususa iityuwa ezishiyekileyo kunye nokungcola. Inkqubo yokuhlamba iyaqhubeka de amanzi okuhlamba afikelele kwi-conductivity echaziweyo, ebonisa ukukhutshwa kokungcola okunyibilikayo.
6. Ukomisa
Inyathelo lokugqibela lokulungiselela i-hydroxyethyl cellulose kukumisa. Eli nyathelo lisusa amanzi angaphezulu, livelise imveliso eyomileyo, enomgubo ofanelekileyo kwizicelo ezahlukeneyo.

Inkqubo:

I-cellulose ye-hydroxyethyl ehlanjiweyo isasazwa kwiitreyi zokomisa okanye ihanjiswe ngetonela yokomisa. Ubushushu bokomisa bulawulwa ngononophelo ukuphepha ukuthotywa kwe-thermal, ngokuqhelekileyo ukusuka kwi-50-80 ° C.
Kungenjalo, ukomisa ngesitshizi kungasetyenziselwa ukomisa ngokukhawuleza nangokufanelekileyo. Ekomisweni kokutshiza, isisombululo se-cellulose se-aqueous hydroxyethyl se-atomized sibe ngamathontsi acolekileyo kwaye yomiswe kumlambo womoya oshushu, okukhokelela kumgubo ocolekileyo.
Imveliso eyomisiweyo igalelwa kwisayizi efunwayo kwaye ipakishwe ukugcinwa kunye nokuhanjiswa.
Ulawulo lomgangatho kunye nezicelo
Kuyo yonke inkqubo yamalungiselelo, amanyathelo angqongqo olawulo lomgangatho aphunyezwa ukuqinisekisa ukuhambelana kunye nomgangatho we-hydroxyethyl cellulose. Iiparamitha eziphambili ezifana ne-viscosity, i-degree of substitution, umxholo womswakama, kunye nobukhulu beengqungquthela zihlala zibekwe esweni.

Usetyenziso:

Pharmaceuticals: Isetyenziswa njenge-agent etyebisayo, i-binder, kunye ne-stabilizer kwimixube efana neepilisi, ukumiswa, kunye ne-ointments.
Izithambiso: Ibonelela nge-viscosity kunye noburhabaxa kwiimveliso ezifana neekhrimu, izinto zokuthambisa, kunye neshampu.
Ipeyinti kunye neengubo: Isebenza njenge-thickener kunye ne-rheology modifier, iphucula iimpawu zesicelo kunye nokuzinza kweepende.
Ishishini lokutya: Isebenza njengento etyebisayo, isizinzisi, kunye ne-emulsifier kwiimveliso ezahlukeneyo zokutya.

Ukulungiswa kwe-cellulose ye-hydroxyethyl kubandakanya uluhlu lweekhemikhali ezichazwe kakuhle kunye neenkqubo zemishini ezijoliswe ekuguquleni i-cellulose ukwazisa amaqela e-hydroxyethyl. Inyathelo ngalinye, ukusuka ekuhlanjululweni kwe-cellulose ukuya komiswe, libalulekile ekuqinisekiseni umgangatho kunye nokusebenza kwemveliso yokugqibela. Iipropathi eziguquguqukayo zeHydroxyethyl cellulose zenza ukuba ibe sisithako esixabiseke kakhulu kumashishini amaninzi, iqaqambisa ukubaluleka kweendlela zokwenziwa ezichanekileyo ukuhlangabezana neemfuno ezithile zezicelo ezahlukeneyo.