Diyaarinta hydroxyethyl cellulose

Hydroxyethyl cellulose (HEC) waa polymer aan-ionic ahayn, oo biyo-milmi leh oo laga soo qaatay cellulose, polymer dabiici ah oo laga helo gidaarada unugyada dhirta. Waxaa si weyn loogu isticmaalaa warshado kala duwan, oo ay ku jiraan dawooyinka, waxyaalaha la isku qurxiyo, rinjiga, iyo xabagta, sababtoo ah dhumucdeeda aad u fiican, sameynta filimada, iyo sifooyinka rheological. Diyaarinta hydroxyethyl cellulose waxay ku lug leedahay etherification ee cellulose leh ethylene oxide hoos xaaladaha alkaline. Nidaamkan waxaa loo kala qaybin karaa dhowr tillaabo oo muhiim ah: nadiifinta cellulose, alkalization, etherification, dhexdhexaadin, dhaqid, iyo qallajin.

1. Sifaynta Cellulose
Talaabada ugu horeysa ee diyaarinta hydroxyethyl cellulose waa nadiifinta cellulose, oo sida caadiga ah laga helo saxarka alwaax ama suufka. cellulose ceeriin waxaa ku jira wasakh sida lignin, hemicellulose, iyo wax-soosaar kale oo ay tahay in laga saaro si loo helo cellulose saafi ah oo sarreeya oo ku habboon wax ka beddelka kiimikada.

Talaabooyinka ku lug leh:

Farsamaynta Farsamada: cellulose-ka ceeriin si farsamaysan ayaa loo farsameeyaa si loo dhimo cabbirkiisa oo loo kordhiyo bedkiisa, fududaynta daawaynta kiimikaad ee xiga.
Daaweynta Kiimikada: cellulose-ka waxaa lagu daaweeyaa kiimikooyin ay ka mid yihiin sodium hydroxide (NaOH) iyo sodium sulfite (Na2SO3) si loo burburiyo lignin iyo hemicellulose, oo ay ku xigto dhaqid iyo bleaching si looga saaro wasakhda haraaga ah oo loo helo cellulose cad, fibrous.

2. Alkalisation
cellulose-ka la safeeyey ayaa markaa alkalized si loo dhaqaajiyo falcelinta etherification. Tani waxay ku lug leedahay in cellulose lagu daweeyo xal aqueous ah ee sodium hydroxide.

Falcelinta:
Cellulose+NaOH→Alkali cellulose

Habka:

Cellulose-ku wuxuu ku xiran yahay biyaha, waxaana lagu daraa xalalka sodium hydroxide. Heerkulka NaOH wuxuu caadi ahaan u dhexeeyaa 10-30%, falcelinta waxa lagu sameeyaa heerkul u dhexeeya 20-40°C.
Isku dar ah ayaa la kiciyay si loo hubiyo in nuugista la midka ah ee alkali, taasoo horseedaysa sameynta alkali cellulose. Dhexdhexaadkani waxa uu aad uga falcelinayaa ethylene oxide, iyada oo fududaynaysa habka etherification.

3. Etherification
Tallaabada ugu muhiimsan ee diyaarinta hydroxyethyl cellulose waa etherification of cellulose alkali leh ethylene oxide. Dareen-celintani waxay soo bandhigaysaa kooxaha hydroxyethyl (-CH2CH2OH) ee laf dhabarta cellulose, taasoo ka dhigaysa mid biyo-milmi leh.

Falcelinta:
Alkali cellulose+Ethylene oxide→Hydroxyethyl cellulose+NaOH

Habka:

Ethylene oxide waxaa lagu daraa cellulose alkali, ha ahaato dufc ama habsocod joogto ah. Dareen-celinta waxaa sida caadiga ah lagu sameeyaa autoclave ama reactor cadaadis.
Xaaladaha falcelinta, oo ay ku jiraan heerkulka (50-100 ° C) iyo cadaadiska (1-5 atm), ayaa si taxadar leh loo xakameeyaa si loo hubiyo beddelka ugu wanaagsan ee kooxaha hydroxyethyl. Heerarka beddelka (DS) iyo beddelka molarka (MS) waa cabbirro muhiim ah oo saameeya sifooyinka alaabta ugu dambeysa.

4. Dhexdhexaadin
Ka dib falcelinta etherification, isku dar ah ayaa ka kooban hydroxyethyl cellulose iyo haraaga sodium hydroxide. Talaabada xigta waa dhexdhexaadin, halkaasoo alkali-ka xad-dhaafka ah lagu dabar-goynayo iyadoo la isticmaalayo asiidh, sida caadiga ah acetic acid (CH3COOH) ama hydrochloric acid (HCl).

Falcelinta:NaOH+HCl→NaCl+H2O

Habka:

Aashitada ayaa si tartiib ah loogu daraa isku dhafka falcelinta ee xaaladaha la xakameeyey si looga fogaado kulaylka xad dhaafka ah loogana hortago xaalufka hydroxyethyl cellulose.
Isku darka dhexdhexaadka ah ayaa markaa lagu hagaajin doonaa pH si loo hubiyo inay ku jirto xadka la rabo, sida caadiga ah agagaarka pH dhexdhexaad ah (6-8).
5. dhaqid
Dhexdhexaadinta ka dib, alaabta waa in la dhaqaa si meesha looga saaro milixda iyo alaabta kale. Tallaabadani waxay muhiim u tahay helitaanka cellulose hydroxyethyl saafi ah.

Habka:

Isku darka falcelinta waxaa lagu qasi jiray biyo, iyo hydroxyethyl cellulose waxaa lagu kala saaraa sifeynta ama centrifugation.
Unugyada hydroxyethyl cellulose ee kala go'ay ayaa si isdaba joog ah loogu dhaqaa biyo fuuqsaday si meesha looga saaro cusbada iyo wasakhda haraaga ah. Habka dhaqidu wuu sii socdaa ilaa biyaha dhaqida ay ka gaarayaan koronto cayiman, taasoo muujineysa ka saarida wasakhda milmaya.
6. Qalajinta
Tallaabada ugu dambeysa ee diyaarinta hydroxyethyl cellulose waa qalajin. Talaabadani waxay meesha ka saaraysaa biyaha xad-dhaafka ah, taasoo keenaysa qalalan, alaab budo ah oo ku habboon codsiyada kala duwan.

Habka:

Hydroxyethyl cellulose-ka la dhaqay wuxuu ku faafaa saxarada qalajinta ama waxaa la mariyaa tunnel-ka qalajinta. Heerkulka qalajinta si taxadar leh ayaa loo xakameeyaa si looga fogaado xaalufka kulaylka, sida caadiga ah wuxuu u dhexeeyaa 50-80 ° C.
Haddii kale, qalajinta buufinta waxaa loo isticmaali karaa qalajinta degdegga ah oo hufan. Qalajinta buufinta, dareeraha hydroxyethyl cellulose ee aqueous waxaa lagu atomeeyaa dhibco fiican waxaana lagu qallajiyaa qulqulka hawo kulul, taasoo keenta budo fiican.
Alaabta engegan ayaa markaa la shiiday ilaa cabbirka walxaha la rabo waxaana lagu shubaa kaydinta iyo qaybinta.
Xakamaynta Tayada iyo Codsiyada
Inta lagu jiro habka diyaarinta, tallaabooyin adag oo lagu xakameynayo tayada ayaa la hirgeliyaa si loo hubiyo joogteynta iyo tayada hydroxyethyl cellulose. Halbeegyada muhiimka ah sida viscosity, heerka beddelka, waxa ku jira qoyaanka, iyo cabbirka walxaha si joogto ah ayaa loola socdaa.

Codsiyada:

Daawooyinka: Waxa loo isticmaalaa sida wakiilka dhumuc, xidhe, iyo xasiliye qaabaynta sida kiniiniyada, ganaaxyada, iyo boomaatada.
Waxyaalaha la isku qurxiyo: Waxay siisaa viscosity iyo texture alaabta sida kiriimyada, loshinka, iyo shaambooyinka.
Rinjiyeynta iyo Dahaarka: Waxay u dhaqmaan sidii dhumuc iyo beddele rheology, hagaajinta sifooyinka codsiga iyo xasilloonida rinji.
Warshadaha Cuntada: Waxay u shaqeysaa sidii dhumuc, dejiye, iyo emulsifier ee badeecadaha kala duwan ee cuntada.

Diyaarinta hydroxyethyl cellulose waxay ku lug leedahay taxane si fiican loo qeexay kiimiko iyo habab farsamo oo loogu talagalay in lagu beddelo cellulose si loo soo bandhigo kooxaha hydroxyethyl. Tallaabo kasta, laga bilaabo nadiifinta cellulose ilaa qalajinta, ayaa muhiim u ah go'aaminta tayada iyo shaqeynta alaabta ugu dambeysa. Guryaha kala duwan ee Hydroxyethyl cellulose waxay ka dhigaan shay qiimo leh oo ku jira warshado badan, taas oo muujinaysa muhiimada hababka wax soo saarka saxda ah si loo buuxiyo shuruudaha gaarka ah ee codsiyada kala duwan.