Kukonzekera kwa hydroxyethyl cellulose

Hydroxyethyl cellulose (HEC) ndi polima yosasungunuka m'madzi yochokera ku cellulose, polima yachilengedwe yomwe imapezeka m'makoma a maselo a zomera. Imagwiritsidwa ntchito kwambiri m'mafakitale osiyanasiyana, kuphatikizapo mankhwala, zodzoladzola, utoto, ndi zomatira, chifukwa cha kukhuthala kwake kwabwino, kupanga filimu, komanso mphamvu zake zolumikizirana ndi rheological. Kukonzekera kwa hydroxyethyl cellulose kumaphatikizapo kusungunuka kwa cellulose ndi ethylene oxide pansi pa mikhalidwe ya alkaline. Njirayi ikhoza kugawidwa m'magawo angapo ofunikira: kuyeretsa cellulose, alkalizing, etherification, neutralization, kutsuka, ndi kuumitsa.

1. Kuyeretsa Cellulose
Gawo loyamba pokonzekera hydroxyethyl cellulose ndikuyeretsa cellulose, yomwe nthawi zambiri imachokera ku matabwa kapena thonje. Cellulose yosaphika imakhala ndi zinthu zosafunika monga lignin, hemicellulose, ndi zina zochotsera zomwe ziyenera kuchotsedwa kuti pakhale cellulose yoyera kwambiri yoyenera kusintha mankhwala.

Masitepe okhudzidwa:

Kukonza Makina: Celulose yosaphika imakonzedwa ndi makina kuti ichepetse kukula kwake ndikuwonjezera malo ake pamwamba, zomwe zimapangitsa kuti mankhwala azigwiritsidwa ntchito pambuyo pake.
Chithandizo cha Mankhwala: Cellulose imachiritsidwa ndi mankhwala monga sodium hydroxide (NaOH) ndi sodium sulfite (Na2SO3) kuti iwononge lignin ndi hemicellulose, kenako imatsukidwa ndi kutsukidwa kuti ichotse zotsalira ndikupeza cellulose yoyera, yopyapyala.

2. Kusakaniza kwa alkalization
Kenako cellulose yoyeretsedwa imasinthidwa kukhala alkali kuti iyambe kugwira ntchito kuti igwire bwino ntchito. Izi zimaphatikizapo kuchiza cellulose ndi sodium hydroxide yamadzi.

Zimene anachita:
Selulosi + NaOH → Alkali cellulose

Ndondomeko:

Maselo amaikidwa m'madzi, ndipo sodium hydroxide solution imawonjezeredwa. Kuchuluka kwa NaOH nthawi zambiri kumakhala pakati pa 10-30%, ndipo zimachitika kutentha pakati pa 20-40°C.
Chosakanizacho chimasakanizidwa kuti chitsimikizire kuti alkali imayamwa mofanana, zomwe zimapangitsa kuti alkali cellulose ipangidwe. Chosakaniza ichi chimakhudzidwa kwambiri ndi ethylene oxide, zomwe zimathandiza kuti etherification ichitike.

3. Kusinthasintha kwa kutentha
Gawo lofunika kwambiri pakukonzekera hydroxyethyl cellulose ndi kusungunuka kwa alkali cellulose ndi ethylene oxide. Izi zimapangitsa kuti magulu a hydroxyethyl (-CH2CH2OH) akhale m'mbuyo mwa cellulose, zomwe zimapangitsa kuti asungunuke m'madzi.

Zimene anachita:
Alkali cellulose+Ethylene oxide→Hydroxyethyl cellulose+NaOH

Ndondomeko:

Ethylene oxide imawonjezeredwa ku alkali cellulose, kaya mu gulu limodzi kapena mosalekeza. Nthawi zambiri zimachitika mu autoclave kapena pressure reactor.
Mikhalidwe ya momwe zinthu zimachitikira, kuphatikizapo kutentha (50-100°C) ndi kupanikizika (1-5 atm), zimawongoleredwa mosamala kuti zitsimikizire kuti magulu a hydroxyethyl asinthidwa bwino. Mlingo wa kusintha (DS) ndi kusintha kwa molar (MS) ndi zinthu zofunika kwambiri zomwe zimakhudza mawonekedwe a chinthu chomaliza.

4. Kusalowererapo
Pambuyo pa etherification reaction, chisakanizocho chimakhala ndi hydroxyethyl cellulose ndi sodium hydroxide yotsalira. Gawo lotsatira ndi neutralization, pomwe alkali yochulukirapo imachepetsedwa pogwiritsa ntchito asidi, yomwe nthawi zambiri imakhala acetic acid (CH3COOH) kapena hydrochloric acid (HCl).

Yankho:NaOH+HCl→NaCl+H2O

Ndondomeko:

Asidi amawonjezeredwa pang'onopang'ono ku chisakanizo cha reaction pansi pa mikhalidwe yolamulidwa kuti apewe kutentha kwambiri ndikuletsa kuwonongeka kwa hydroxyethyl cellulose.
Kenako chisakanizo chosasunthika chimasinthidwa pH kuti chitsimikizire kuti chili mkati mwa mulingo womwe mukufuna, nthawi zambiri mozungulira pH yopanda mbali (6-8).
5. Kusamba
Pambuyo pochotsa mchere ndi zinthu zina zotsala, mankhwalawa ayenera kutsukidwa kuti achotse mchere ndi zinthu zina zotsala. Gawo ili ndi lofunika kwambiri kuti mupeze hydroxyethyl cellulose yoyera.

Ndondomeko:

Kusakaniza kwa reaction kumachepetsedwa ndi madzi, ndipo hydroxyethyl cellulose imalekanitsidwa ndi kusefa kapena centrifugation.
Hydroxyethyl cellulose yolekanitsidwa imatsukidwa mobwerezabwereza ndi madzi oyeretsedwa kuti ichotse mchere wotsala ndi zinyalala. Kutsukaku kumapitirira mpaka madzi otsukidwawo afike pamlingo winawake, zomwe zimasonyeza kuti zinyalala zosungunuka zimachotsedwa.
6. Kuuma
Gawo lomaliza pakukonzekera hydroxyethyl cellulose ndikuwumitsa. Gawoli limachotsa madzi ochulukirapo, zomwe zimapangitsa kuti pakhale ufa wouma komanso woyenera kugwiritsidwa ntchito m'njira zosiyanasiyana.

Ndondomeko:

Hydxyethyl cellulose yotsukidwa imayikidwa pa thireyi zoumitsira kapena kutumizidwa kudzera mu ngalande youmitsira. Kutentha kwa kuumitsa kumayendetsedwa mosamala kuti kutentha kusawonongeke, nthawi zambiri kuyambira 50-80°C.
Kapenanso, kuumitsa kwa spray kungagwiritsidwe ntchito poumitsa mwachangu komanso moyenera. Poumitsa kwa spray, madzi a hydroxyethyl cellulose solution amasanduka madontho ang'onoang'ono ndikuumitsidwa mumtsinje wotentha, zomwe zimapangitsa kuti ufa ukhale wabwino.
Kenako chinthu chouma chimaphwanyidwa mpaka kukula kwa tinthu tomwe tikufuna ndikupakidwa kuti chisungidwe ndikugawidwa.
Kuwongolera Ubwino ndi Mapulogalamu
Munthawi yonse yokonzekera, njira zowongolera bwino zaubwino zimagwiritsidwa ntchito kuti zitsimikizire kuti hydroxyethyl cellulose ndi yofanana komanso yabwino. Zinthu zofunika monga kukhuthala, kuchuluka kwa kusintha, kuchuluka kwa chinyezi, ndi kukula kwa tinthu timeneti zimawunikidwa nthawi zonse.

Mapulogalamu:

Mankhwala: Amagwiritsidwa ntchito ngati chowonjezera kukhuthala, chomangira, komanso chokhazikika m'mapiritsi monga mapiritsi, zosungunulira, ndi mafuta odzola.
Zodzoladzola: Zimapereka kukhuthala ndi kapangidwe kake ku zinthu monga mafuta, mafuta odzola, ndi shampu.
Utoto ndi Zophimba: Zimagwira ntchito ngati chowonjezera komanso chosinthira rheology, kukonza mawonekedwe ogwiritsira ntchito komanso kukhazikika kwa utoto.
Makampani Ogulitsa Chakudya: Amagwira ntchito ngati chokhuthala, chokhazikika, komanso chosakaniza zinthu zosiyanasiyana muzakudya.

Kukonzekera kwa hydroxyethyl cellulose kumaphatikizapo njira zingapo zamakemikolo ndi zamakaniko zomwe cholinga chake ndi kusintha cellulose kuti ipange magulu a hydroxyethyl. Gawo lililonse, kuyambira pakuyeretsa cellulose mpaka kuumitsa, ndilofunika kwambiri pakuzindikira mtundu ndi magwiridwe antchito a chinthu chomaliza. Kapangidwe ka hydroxyethyl cellulose kamapangitsa kuti ikhale chinthu chofunikira kwambiri m'mafakitale ambiri, zomwe zikuwonetsa kufunika kwa njira zodziwikiratu zopangira kuti zikwaniritse zofunikira za ntchito zosiyanasiyana.