Ukulungiswa kwe-hydroxyethyl cellulose

I-Hydroxyethyl cellulose (HEC) yi-polymer engeyiyo ionic, enyibilikayo emanzini ephuma kwi-cellulose, i-polymer yendalo efumaneka kwiindonga zeeseli zezityalo. Isetyenziswa kakhulu kumashishini ahlukeneyo, kubandakanya amayeza, izinto zokuthambisa, iipeyinti, kunye nezincamathelisi, ngenxa yeempawu zayo ezibalaseleyo zokutyeba, ukwenza ifilimu, kunye neempawu ze-rheological. Ukulungiswa kwe-hydroxyethyl cellulose kubandakanya ukufakelwa kwe-cellulose nge-ethylene oxide phantsi kweemeko ze-alkaline. Le nkqubo inokwahlulwa ibe ngamanyathelo aliqela abalulekileyo: ukucocwa kwe-cellulose, ukufakelwa kwe-alkalization, ukufakelwa kwe-etherification, ukuthamba, ukuhlamba, kunye nokomisa.

1. Ukucocwa kweCellulose
Inyathelo lokuqala ekulungiseleleni i-hydroxyethyl cellulose kukucocwa kwe-cellulose, edla ngokuvela kwi-pulp yomthi okanye kwi-cotton linters. I-cellulose eluhlaza iqulethe ukungcola okufana ne-lignin, i-hemicellulose, kunye nezinye izinto ezikhuphayo ekufuneka zisuswe ukuze kufunyanwe i-cellulose ecocekileyo kakhulu efanelekileyo yokuguqulwa kweekhemikhali.

Amanyathelo abandakanyekayo:

Ukucubungula ngoomatshini: I-cellulose eluhlaza icutshungulwa ngoomatshini ukuze inciphise ubukhulu bayo kwaye yonyuse indawo yayo engaphezulu, nto leyo eququzelela unyango lweekhemikhali olulandelayo.
Unyango lweeKhemikhali: I-cellulose inyangwa ngeekhemikhali ezifana ne-sodium hydroxide (NaOH) kunye ne-sodium sulfite (Na2SO3) ukuze kuqhekeke i-lignin kunye ne-hemicellulose, kulandele ukuhlamba kunye noku-bleach ukususa ukungcola okuseleyo kunye nokufumana i-cellulose emhlophe, ene-fibrous.

2. Ukwenziwa kwe-Alkalization
Emva koko i-cellulose ecociweyo iyalungiswa ukuze isebenze kwi-etherification reaction. Oku kuquka ukunyanga i-cellulose ngesisombululo samanzi se-sodium hydroxide.

Impendulo:
I-Cellulose+NaOH→I-Alkali cellulose

Inkqubo:

I-cellulose ifakwa emanzini, kwaye kongezwa isisombululo se-sodium hydroxide. Uxinzelelo lwe-NaOH ludla ngokuba phakathi kwe-10-30%, kwaye impendulo yenziwa kumaqondo obushushu aphakathi kwama-20-40°C.
Umxube uyaxutywa ukuqinisekisa ukufunxwa okufanayo kwe-alkali, nto leyo ekhokelela ekwakhiweni kwe-alkali cellulose. Le intermediate isabela ngakumbi kwi-ethylene oxide, nto leyo enceda inkqubo ye-etherification.

3. Ukufakelwa kwe-Ether
Inyathelo elibalulekileyo ekulungiseleleni i-hydroxyethyl cellulose kukufakelwa kwe-alkali cellulose nge-ethylene oxide. Le mpendulo ingenisa amaqela e-hydroxyethyl (-CH2CH2OH) kwi-cellulose backbone, nto leyo eyenza ukuba inyibilike emanzini.

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

Inkqubo:

I-ethylene oxide yongezwa kwi-alkali cellulose, nokuba yi-batch okanye inkqubo eqhubekayo. I-reaction idla ngokuqhutywa kwi-autoclave okanye kwi-pressure reactor.
Iimeko zokusabela, kuquka ubushushu (50-100°C) kunye noxinzelelo (1-5 atm), zilawulwa ngononophelo ukuqinisekisa ukutshintshwa okufanelekileyo kwamaqela e-hydroxyethyl. Iqondo lokutshintshwa (DS) kunye nokutshintshwa kwe-molar (MS) ziiparameter ezibalulekileyo ezichaphazela iimpawu zemveliso yokugqibela.

4. Ukungathathi cala
Emva kwe-etherification reaction, umxube uqulethe i-hydroxyethyl cellulose kunye ne-residual sodium hydroxide. Inyathelo elilandelayo kukunciphisa i-alkali, apho i-alkali egqithisileyo isuswa kusetyenziswa i-asidi, edla ngokuba yi-acetic acid (CH3COOH) okanye i-hydrochloric acid (HCl).

Impendulo:NaOH+HCl→NaCl+H2O

Inkqubo:

I-asidi yongezwa kancinci kancinci kumxube we-reaction phantsi kweemeko ezilawulwayo ukuze kuthintelwe ubushushu obugqithisileyo kwaye kuthintelwe ukuwohloka kwe-hydroxyethyl cellulose.
Umxube onganyangekiyo emva koko ulungiswa i-pH ukuqinisekisa ukuba ingaphakathi koluhlu olufunekayo, ngesiqhelo ijikeleze i-pH enganyangekiyo (6-8).
5. Ukuhlamba
Emva kokungashukumi, imveliso kufuneka ihlanjwe ukuze kususwe iityuwa kunye nezinye izinto eziphuma kuyo. Eli nyathelo libalulekile ekufumaneni i-hydroxyethyl cellulose ecocekileyo.

Inkqubo:

Umxube wempendulo uxutywa ngamanzi, kwaye i-hydroxyethyl cellulose yahlulwe ngokuhluzwa okanye ngokucocwa.
I-hydroxyethyl cellulose ehlukanisiweyo ihlanjwa ngokuphindaphindiweyo ngamanzi acocekileyo ukuze kususwe iityuwa eziseleyo kunye nokungcola. Inkqubo yokuhlamba iyaqhubeka ide amanzi okuhlamba afikelele kwi-conductivity ethile, ebonisa ukususwa kokungcola okunyibilikayo.
6. Ukomisa
Inyathelo lokugqibela ekulungiseleleni i-hydroxyethyl cellulose kukomisa. Eli nyathelo lisusa amanzi angaphezulu, nto leyo evelisa imveliso eyomileyo neyimpuphu efanelekileyo kwiindlela ezahlukeneyo zokusetyenziswa.

Inkqubo:

I-hydroxyethyl cellulose ehlanjiweyo isasazwa kwiitreyi zokomisa okanye ihanjiswe ngetonela yokomisa. Ubushushu bokomisa bulawulwa ngononophelo ukuze kuthintelwe ukubola kobushushu, ngokuqhelekileyo ukusuka kwi-50-80°C.
Okanye, ukomisa ngesitshizi kungasetyenziselwa ukomisa ngokukhawuleza nangokufanelekileyo. Xa ukomisa ngesitshizi, isisombululo se-hydroxyethyl cellulose esimanzi siyaguqulwa sibe ngamaconsi amancinci size somiswe kumlambo womoya oshushu, nto leyo ephumela kwimpuphu ecolekileyo.
Imveliso eyomileyo emva koko iyasilwa ibe nkulu kangangoko ifunekayo ize ipakishwe ukuze igcinwe kwaye isasazwe.
Ulawulo loMgangatho kunye nezicelo
Kuyo yonke inkqubo yokulungiselela, amanyathelo okulawula umgangatho aqatha ayasetyenziswa ukuqinisekisa ukuhambelana kunye nomgangatho we-hydroxyethyl cellulose. Iiparameter eziphambili ezifana ne-viscosity, ubungakanani bokutshintshwa, umxholo womswakama, kunye nobukhulu bezinto ezincinci zijongwa rhoqo.

Izicelo:

Amayeza: Asetyenziswa njenge-arhente yokutyeba, i-binder, kunye ne-stabilizer kwiifomyula ezifana neepilisi, ii-suspensions, kunye ne-ointments.
Izinto zokuthambisa: Inika uburhabaxa kunye nokuthungwa kwiimveliso ezinje ngeekhrimu, iiloshini, kunye neeshampu.
Iipeyinti kunye neengubo: Zisebenza njengesithambisi-ndlela sokwandisa nokuguqula i-rheology, ziphucula iimpawu zokusetyenziswa kunye nozinzo lweepeyinti.
Ishishini Lokutya: Lisebenza njengesithambisi-zinzisi, njengesiqinisi, kunye nesixubisisi kwiimveliso ezahlukeneyo zokutya.

Ukulungiswa kwe-hydroxyethyl cellulose kubandakanya uthotho lweenkqubo zeekhemikhali kunye nezoomatshini ezichazwe kakuhle ezijolise ekuguquleni i-cellulose ukuze kungeniswe amaqela e-hydroxyethyl. Inyathelo ngalinye, ukusuka ekucoceni i-cellulose ukuya ekomiseni, libalulekile ekumiseleni umgangatho kunye nokusebenza kwemveliso yokugqibela. Iimpawu ze-Hydroxyethyl cellulose eziguquguqukayo zenza ukuba ibe sisithako esixabisekileyo kumashishini amaninzi, nto leyo egxininisa ukubaluleka kweendlela zokwenza imveliso ngokuchanekileyo ukuze kuhlangatyezwane neemfuno ezithile zezicelo ezahlukeneyo.