Diyaarinta hydroxyethyl cellulose

Hydroxyethyl cellulose (HEC) waa polymer aan ionic ahayn, oo biyaha ku milma oo laga soo qaatay cellulose, oo ah polymer dabiici ah oo laga helo derbiyada unugyada dhirta. Waxaa si weyn loogu isticmaalaa warshado kala duwan, oo ay ku jiraan daawooyinka, qurxinta, rinjiyeynta, iyo dhejisyada, sababtoo ah dhumucdeeda aadka u fiican, sameynta filimada, iyo sifooyinka rheological. Diyaarinta hydroxyethyl cellulose waxay ku lug leedahay etherification of cellulose oo leh ethylene oxide xaaladaha alkaline. Habkan waxaa loo qaybin karaa dhowr tallaabo oo muhiim ah: nadiifinta cellulose, alkalization, etherification, dhexdhexaadinta, dhaqidda, iyo qalajinta.

1. Nadiifinta Cellulose
Tallaabada ugu horreysa ee diyaarinta hydroxyethyl cellulose waa nadiifinta cellulose, oo badanaa laga helo saxarka alwaaxa ama suufka. Cellulose-ka cayriin wuxuu ka kooban yahay wasakh sida lignin, hemicellulose, iyo waxyaabo kale oo soo saara oo ay tahay in laga saaro si loo helo cellulose saafi ah oo ku habboon wax ka beddelka kiimikada.

Tallaabooyinka ku lug leh:

Habaynta Farsamada: Cellulose-ka cayriin waxaa si farsamo ahaan loo farsameeyaa si loo yareeyo cabbirkiisa loona kordhiyo baaxadda dusha sare, taasoo sahlaysa daawaynta kiimikada ee xigta.
Daawaynta Kiimikada: Cellulose-ka waxaa lagu daaweeyaa kiimikooyin sida sodium hydroxide (NaOH) iyo sodium sulfite (Na2SO3) si loo burburiyo lignin iyo hemicellulose, ka dibna la dhaqo oo la caddeeyo si looga saaro wasakhda hartay loona helo cellulose cad oo fibre ah.

2. Alkalisaynta
Cellulose-ka la nadiifiyey ayaa markaa la alkaliyaa si loogu hawlgeliyo fal-celinta etherification-ka. Tani waxay ku lug leedahay daawaynta cellulose-ka xal biyood ah oo sodium hydroxide ah.

Falcelinta:
Cellulose+NaOH→Cellulose-ka Alkaalka ah

Habka:

Cellulose-ka waxaa lagu dahaadhaa biyaha, waxaana lagu daraa xalka sodium hydroxide. Xoogga NaOH wuxuu caadi ahaan u dhexeeyaa 10-30%, falgalkana waxaa lagu sameeyaa heerkul u dhexeeya 20-40°C.
Isku darka ayaa la walaaqayaa si loo hubiyo nuugista alkali ee isku mid ah, taasoo horseedaysa sameynta alkali cellulose. Dhexdhexaadkani wuxuu si aad ah uga falceliyaa oksaydhka ethylene, taasoo sahlaysa habka etherification.

3. Kala-soocidda
Tallaabada ugu muhiimsan ee diyaarinta hydroxyethyl cellulose waa etherification-ka alkali cellulose oo leh ethylene oxide. Falgalkani wuxuu kooxaha hydroxyethyl (-CH2CH2OH) ku soo daraa laf-dhabarta cellulose, taasoo ka dhigaysa mid biyo ku milma.

Falcelinta:
Cellulose Alkali+Oksayd Ethylene→Hydroxyethyl cellulose+NaOH

Habka:

Ethylene oxide waxaa lagu daraa cellulose-ka alkali, ha ahaato mid dufcad ah ama mid joogto ah. Falcelinta waxaa badanaa lagu sameeyaa autoclave ama reactor cadaadis.
Xaaladaha falgalka, oo ay ku jiraan heerkulka (50-100°C) iyo cadaadiska (1-5 atm), si taxaddar leh ayaa loo xakameeyaa si loo hubiyo beddelka ugu habboon ee kooxaha hydroxyethyl. Heerka beddelka (DS) iyo beddelka molar (MS) waa halbeegyo muhiim ah oo saameeya sifooyinka badeecada ugu dambeysa.

4. Dhexdhexaadin
Ka dib falgalka etherification, isku darka waxaa ku jira hydroxyethyl cellulose iyo sodium hydroxide haray. Tallaabada xigta waa dhexdhexaadin, halkaas oo alkali xad-dhaafka ah lagu dhexdhexaadiyo iyadoo la isticmaalayo asiidh, caadi ahaan acetic acid (CH3COOH) ama hydrochloric acid (HCl).

Falcelinta: NaOH+HCl→NaCl+H2O

Habka:

Asiidhka ayaa si tartiib tartiib ah loogu daraa isku darka falcelinta iyadoo la raacayo xaalado la xakameeyey si looga fogaado kulaylka xad-dhaafka ah iyo ka hortagga burburka hydroxyethyl cellulose.
Isku darka dhexdhexaadka ah ayaa markaa lagu sameeyaa hagaajinta pH si loo hubiyo inuu ku jiro xadka la rabo, badanaa qiyaastii pH dhexdhexaad ah (6-8).
5. Dhaqidda
Ka dib marka la dhexgeliyo, badeecada waa in la dhaqo si looga saaro milixda iyo waxyaabaha kale ee ka soo baxa. Tallaabadani waa mid muhiim u ah helitaanka hydroxyethyl cellulose saafi ah.

Habka:

Isku darka falgalka waxaa lagu qasi jiray biyo, cellulose-ka hydroxyethyl-kana waxaa lagu kala saaraa shaandhayn ama centrifugation.
Unugyada hydroxyethyl cellulose ee kala go'ay waxaa si isdaba joog ah loogu dhaqaa biyo la miiray si looga saaro cusbada iyo wasakhda hartay. Habka dhaqiddu wuxuu sii socdaa ilaa biyaha dhaqiddu ay gaaraan meel gaar ah oo la cayimay, taasoo muujinaysa in laga saarayo wasakhda milmi karta.
6. Qallajinta
Tallaabada ugu dambeysa ee diyaarinta hydroxyethyl cellulose waa qalajinta. Tallaabadani waxay ka saartaa biyaha xad-dhaafka ah, iyadoo soo saaraysa badeeco qalalan oo budo ah oo ku habboon isticmaalka kala duwan.

Habka:

Cellulose-ka hydroxyethyl ee la dhaqay waxaa lagu faafiyaa saxaaradaha qalajinta ama waxaa la mariyaa god qalajin ah. Heerkulka qalajinta si taxaddar leh ayaa loo xakameeyaa si looga fogaado burburka kulaylka, oo caadi ahaan u dhexeeya 50-80°C.
Haddii kale, qalajinta buufinta waxaa loo isticmaali karaa qalajinta degdega ah oo hufan. Qalajinta buufinta, xalka hydroxyethyl cellulose ee biyaha ku jira ayaa loo kala saaraa dhibco yaryar ka dibna lagu qalajiyaa biyo kulul, taasoo keenta budo fiican.
Badeecada la qalajiyey ayaa markaa la shiiday ilaa inta la rabo ee walxaha la rabo, ka dibna la xirxiray si loogu kaydiyo loona qaybiyo.
Xakamaynta Tayada iyo Codsiyada
Inta lagu jiro habka diyaarinta, tallaabooyin adag oo lagu xakameynayo tayada ayaa la hirgeliyaa si loo hubiyo isku dheelitirka iyo tayada hydroxyethyl cellulose. Qodobbada muhiimka ah sida dheellitirka, heerka beddelka, qoyaanka, iyo cabbirka walxaha ayaa si joogto ah loola socdaa.

Codsiyada:

Daawooyinka: Waxaa loo isticmaalaa sidii wakiil qaro weyn, xidhmo, iyo xasiliye qaab-dhismeedyo sida kiniinno, ganaaxyo, iyo boomaatooyin.
Qurxinta: Waxay siisaa dheqsi iyo qaab-dhismeed alaabada sida kareemada, looshinada, iyo shaambooyada.
Rinjiyeynta iyo Dahaarka: Waxay u shaqeysaa sidii wax ka beddele dhumuc iyo rheology ah, iyadoo hagaajineysa sifooyinka isticmaalka iyo xasilloonida rinjiga.
Warshadaha Cuntada: Waxay u shaqeeyaan sidii dhumuc-dhegeeye, xasiliye, iyo emulsifier badeecooyin cunto oo kala duwan.

Diyaarinta hydroxyethyl cellulose waxay ku lug leedahay taxane ah habab kiimiko iyo farsamo oo si fiican loo qeexay oo loogu talagalay in wax laga beddelo cellulose si loo soo bandhigo kooxaha hydroxyethyl. Tallaabo kasta, laga bilaabo nadiifinta cellulose ilaa qalajinta, waa mid muhiim u ah go'aaminta tayada iyo shaqeynta badeecada kama dambaysta ah. Astaamaha kala duwan ee hydroxyethyl cellulose waxay ka dhigayaan qayb qiimo leh warshado badan, iyagoo muujinaya muhiimadda dhaqamada wax soo saarka saxda ah si loo daboolo shuruudaha gaarka ah ee codsiyada kala duwan.