Ukulungiswa kwe-hydroxyethyl cellulose

I-Hydroxyethyl cellulose (HEC) iyi-polymer engeyona i-ionic, encibilika emanzini etholakala ku-cellulose, i-polymer yemvelo etholakala ezindongeni zamaseli ezitshalo. Isetshenziswa kakhulu ezimbonini ezahlukahlukene, kufaka phakathi ezemithi, izimonyo, upende, nezinamatheliso, ngenxa yokuqina kwayo okuhle kakhulu, ukwakheka kwefilimu, kanye nezakhiwo ze-rheological. Ukulungiswa kwe-hydroxyethyl cellulose kuhilela ukufakwa kwe-cellulose nge-ethylene oxide ngaphansi kwezimo ze-alkali. Le nqubo ingahlukaniswa ngezinyathelo ezimbalwa ezibalulekile: ukuhlanzwa kwe-cellulose, i-alkalization, i-etherification, i-neutralization, ukugeza, nokomisa.

1. Ukuhlanzwa kweCellulose
Isinyathelo sokuqala sokulungiswa kwe-hydroxyethyl cellulose ukuhlanzwa kwe-cellulose, ngokuvamile etholakala ku-pulp yokhuni noma kumalitha kakotini. I-cellulose eluhlaza iqukethe ukungcola okufana ne-lignin, i-hemicellulose, nezinye izinto ezikhishwayo okufanele zisuswe ukuze kutholwe i-high-purity cellulose efanele ukuguqulwa kwamakhemikhali.

Izinyathelo ezihilelekile:

Ukucutshungulwa Kwemishini: I-cellulose eluhlaza icutshungulwa ngomshini ukuze kwehliswe usayizi wayo futhi kwandise indawo yayo, kube lula ukwelashwa kwamakhemikhali okulandelayo.
Ukwelashwa Ngamakhemikhali: I-cellulose iphathwa ngamakhemikhali afana ne-sodium hydroxide (NaOH) kanye ne-sodium sulfite (Na2SO3) ukuze ihlehlise i-lignin ne-hemicellulose, kulandelwa ukugeza nokugcoba ukuze kukhishwe ukungcola okusele futhi kutholakale i-cellulose emhlophe, ene-fibrous.

2. I-Alkalization
I-cellulose ehlanjululwe ibe isifakwa i-alkali ukuze isebenze ukuze kusabela i-etherification. Lokhu kuhilela ukwelapha i-cellulose ngesisombululo esinamanzi se-sodium hydroxide.

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

Inqubo:

I-cellulose imisiwe emanzini, futhi isisombululo se-sodium hydroxide siyengezwa. Ukuhlushwa kwe-NaOH kuvame ukusukela ku-10-30%, futhi ukusabela kwenziwa emazingeni okushisa aphakathi kuka-20-40°C.
Ingxube iyanyakaziswa ukuze kuqinisekiswe ukumuncwa okufanayo kwe-alkali, okuholela ekwakhekeni kwe-alkali cellulose. Lokhu okuphakathi kuyasebenza kakhulu ku-ethylene oxide, kwenza inqubo ye-etherification.

3. I-Etherification
Isinyathelo esibalulekile ekulungiseleleni i-hydroxyethyl cellulose ukufakwa kwe-alkali cellulose nge-ethylene oxide. Lokhu kusabela kwethula amaqembu e-hydroxyethyl (-CH2CH2OH) kumgogodla we-cellulose, okuwenza ancibilike emanzini.

Ukusabela:
I-Alkali cellulose+Ethylene oxide→I-Hydroxyethyl cellulose+NaOH

Inqubo:

I-ethylene oxide yengezwa ku-alkali cellulose, kungaba ngeqoqo noma inqubo eqhubekayo. Ukusabela ngokuvamile kwenziwa ku-autoclave noma ku-pressure reactor.
Izimo zokusabela, okuhlanganisa izinga lokushisa (50-100°C) nokucindezela (1-5 atm), zilawulwa ngokucophelela ukuze kuqinisekiswe ukushintshwa okufanelekile kwamaqembu e-hydroxyethyl. I-degree of substitution (DS) kanye ne-molar substitution (MS) amapharamitha abalulekile athonya izici zomkhiqizo wokugcina.

4. Ukungathathi hlangothi
Ngemuva kokusabela kwe-etherification, ingxube iqukethe i-hydroxyethyl cellulose ne-residual sodium hydroxide. Isinyathelo esilandelayo siwukungathathi hlangothi, lapho i-alkali eyeqile ichithwa kusetshenziswa i-asidi, ngokuvamile i-acetic acid (CH3COOH) noma i-hydrochloric acid (HCl).

Ukusabela:NaOH+HCl→NaCl+H2O

Inqubo:

I-asidi yengezwa kancane kancane engxubeni yokusabela ngaphansi kwezimo ezilawulwayo ukuze kugwenywe ukushisa okukhulu futhi kuvimbele ukuwohloka kwe-hydroxyethyl cellulose.
Ingxube engathathi hlangothi ibe isingaphansi kokulungiswa kwe-pH ukuze kuqinisekiswe ukuthi ingaphakathi kwebanga elifunekayo, ngokuvamile elizungeze i-pH engathathi hlangothi (6-8).
5. Ukugeza
Ukulandela ukungathathi hlangothi, umkhiqizo kufanele ugezwe ukuze kukhishwe usawoti kanye neminye imikhiqizo. Lesi sinyathelo sibalulekile ekutholeni i-hydroxyethyl cellulose emsulwa.

Inqubo:

Ingxube yokusabela ihlanjululwa ngamanzi, futhi i-hydroxyethyl cellulose ihlukaniswa ngokuhlunga noma i-centrifugation.
I-hydroxyethyl cellulose ehlukanisiwe igezwa ngokuphindaphindiwe ngamanzi akhishwe ukuze kukhishwe usawoti osele kanye nokungcola. Inqubo yokugeza iyaqhubeka kuze kube yilapho amanzi okugeza efinyelela ku-conductivity ecacisiwe, okubonisa ukususwa kokungcola okuncibilikayo.
6. Ukomisa
Isinyathelo sokugcina sokulungiswa kwe-hydroxyethyl cellulose ukumisa. Lesi sinyathelo sisusa amanzi amaningi, sikhiqiza umkhiqizo owomile, oyimpuphu ofanele ukusetshenziswa okuhlukahlukene.

Inqubo:

I-hydroxyethyl cellulose egeziwe isakazwa kumathreyi okomisa noma idluliselwe emhubheni wokomisa. Izinga lokushisa lokumisa lilawulwa ngokucophelela ukuze kugwenywe ukuwohloka kokushisa, ngokuvamile okusukela ku-50-80°C.
Kungenjalo, ukomiswa kwesifutho kungasetshenziselwa ukomisa ngokushesha nangempumelelo. Ekomisweni kwesifutho, isixazululo se-aqueous hydroxyethyl cellulose sifakwa i-athomu sibe amaconsi amahle bese somiswa emoyeni oshisayo, okuholela ekubeni impushana ecolekile.
Umkhiqizo omisiwe ube usugaywa ube usayizi wezinhlayiyana oyifunayo bese upakishwa ukuze ugcinwe futhi usatshalaliswe.
Ukulawulwa Kwekhwalithi Nezicelo
Kuyo yonke inqubo yokulungiselela, izinyathelo eziqinile zokulawula ikhwalithi ziyasetshenziswa ukuze kuqinisekiswe ukuhambisana kanye nekhwalithi ye-hydroxyethyl cellulose. Imingcele ebalulekile efana ne-viscosity, izinga lokushintsha, okuqukethwe komswakama, nosayizi wezinhlayiyana zibhekwa njalo.

Izicelo:

Imithi: Isetshenziswa njenge-ejenti yokuqina, i-binder, kanye ne-stabilizer ekwenziweni njengamaphilisi, okokumiswa, namafutha okugcoba.
Izimonyo: Ihlinzeka nge-viscosity kanye nokuthungwa emikhiqizweni efana nokhilimu, izinto zokuthambisa, nama-shampoos.
Amapende nama-Coatings: Isebenza njenge-thickener ne-rheology modifier, ithuthukisa izakhiwo zokufaka kanye nokuzinza kwamapende.
Imboni Yokudla: Isebenza njenge-thickener, stabilizer, kanye ne-emulsifier emikhiqizweni ehlukahlukene yokudla.

Ukulungiswa kwe-hydroxyethyl cellulose kuhilela uchungechunge lwamakhemikhali achazwe kahle kanye nezinqubo zemishini okuhloswe ngazo ukuguqula i-cellulose ukwethula amaqembu e-hydroxyethyl. Isinyathelo ngasinye, ukusuka ekuhlanzweni kwe-cellulose kuya ekomisweni, sibalulekile ekunqumeni ikhwalithi nokusebenza komkhiqizo wokugcina. Izakhiwo ezihlukahlukene ze-Hydroxyethyl cellulose ziyenza ibe isithako esiyigugu ezimbonini eziningi, igqamisa ukubaluleka kwezinqubo zokukhiqiza ezinembayo ukuze kuhlangatshezwane nezidingo ezithile zezinhlelo zokusebenza ezihlukahlukene.