Kukonzekera kwa hydroxyethyl cellulose

Hydroxyethyl cellulose (HEC) ndi polima yopanda ionic, yosungunuka m'madzi yochokera ku cellulose, polima yachilengedwe yomwe imapezeka m'makoma a zomera. Amagwiritsidwa ntchito kwambiri m'mafakitale osiyanasiyana, kuphatikizapo mankhwala, zodzoladzola, utoto, ndi zomatira, chifukwa cha kukhuthala kwake, kupanga mafilimu, ndi rheological properties. Kukonzekera kwa hydroxyethyl cellulose kumaphatikizapo etherification wa cellulose ndi ethylene oxide pansi pa zinthu zamchere. Izi zitha kugawidwa m'magulu angapo: kuyeretsa cellulose, alkalization, etherification, neutralization, kutsuka, ndi kuyanika.

1. Kuyeretsa Ma cellulose
Gawo loyamba pokonzekera hydroxyethyl cellulose ndikuyeretsa mapadi, omwe amapangidwa kuchokera ku zamkati zamatabwa kapena ma linter a thonje. Selulosi yaiwisi imakhala ndi zonyansa monga lignin, hemicellulose, ndi zina zowonjezera zomwe ziyenera kuchotsedwa kuti zipeze cellulose yoyera kwambiri yoyenera kusinthidwa kwa mankhwala.

Masitepe okhudzidwa:

Mechanical Processing: Selulosi yaiwisi yaiwisi imakonzedwa mwamakina kuti ichepetse kukula kwake ndikuwonjezera malo ake, ndikupangitsa chithandizo chamankhwala chotsatira.
Mankhwala Ochizira Mankhwala: Ma cellulose amapangidwa ndi mankhwala monga sodium hydroxide (NaOH) ndi sodium sulfite (Na2SO3) kuti aphwanye lignin ndi hemicellulose, kenako kuchapa ndi kuyeretsa kuchotsa zonyansa zotsalira ndikupeza cellulose yoyera, ya fibrous.

2. Alkalization
Ma cellulose oyeretsedwa amapangidwa ndi alkali kuti ayambitse kuti achitepo kanthu. Izi zimaphatikizapo kuchiza cellulose ndi yankho lamadzi la sodium hydroxide.

Zochita:
Ma cellulose+NaOH→Ma cellulose a Alkali

Kachitidwe:

Ma cellulose amayimitsidwa m'madzi, ndipo yankho la sodium hydroxide limawonjezeredwa. Kuchuluka kwa NaOH nthawi zambiri kumachokera ku 10-30%, ndipo zomwe zimachitika zimachitika pa kutentha pakati pa 20-40 ° C.
Kusakaniza kumalimbikitsidwa kuti zitsimikizire kuyamwa kwa alkali, zomwe zimapangitsa kupanga alkali cellulose. Izi zapakatikati zimakhala zotakasuka kwambiri ku ethylene oxide, zomwe zimathandizira kuti etherification ichitike.

3. Etherification
Chinthu chofunika kwambiri pakukonzekera hydroxyethyl cellulose ndi etherification ya cellulose ya alkali ndi ethylene oxide. Izi zimabweretsa magulu a hydroxyethyl (-CH2CH2OH) mumsana wa cellulose, ndikupangitsa kuti sungunuka m'madzi.

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

Kachitidwe:

Ethylene oxide imawonjezeredwa ku cellulose ya alkali, mwina mu batch kapena mosalekeza. Zomwe zimachitika nthawi zambiri zimachitika mu autoclave kapena pressure reactor.
Zomwe zimachitika, kuphatikizapo kutentha (50-100 ° C) ndi kuthamanga (1-5 atm), zimayendetsedwa mosamala kuti zitsimikizire kuti m'malo mwa magulu a hydroxyethyl. Digiri ya kusintha (DS) ndi molar substitution (MS) ndi magawo ofunikira omwe amakhudza mawonekedwe a chinthu chomaliza.

4. Kusalowerera ndale
Pambuyo anachita etherification, osakaniza lili hydroxyethyl mapadi ndi otsalira sodium hydroxide. Chotsatira ndicho kusalowerera ndale, pomwe alkali wochulukirapo amachotsedwa pogwiritsa ntchito asidi, nthawi zambiri acetic acid (CH3COOH) kapena hydrochloric acid (HCl).

Zomwe zimachitika:NaOH+HCl→NaCl+H2O

Kachitidwe:

The asidi pang`onopang`ono anawonjezera anachita osakaniza pansi ankalamulira kutentha kwambiri ndi kupewa kuwonongeka kwa hydroxyethyl mapadi.
Kusakaniza kosasunthika kumasinthidwa ndi pH kuti kuwonetsetse kuti kuli mkati mwazomwe mukufuna, nthawi zambiri mozungulira pH (6-8).
5. Kusamba
Kutsatira neutralization, mankhwala ayenera kutsukidwa kuchotsa mchere ndi zina zopangidwa. Gawo ili ndilofunika kuti mupeze hydroxyethyl cellulose.

Kachitidwe:

Zomwe zimasakanikirana zimachepetsedwa ndi madzi, ndipo cellulose ya hydroxyethyl imasiyanitsidwa ndi kusefera kapena centrifugation.
Ma cellulose olekanitsidwa a hydroxyethyl amatsukidwa mobwerezabwereza ndi madzi oyeretsedwa kuti achotse mchere wotsalira ndi zonyansa. Kutsuka kumapitirira mpaka madzi osamba afika pamtundu wina, kusonyeza kuchotsedwa kwa zonyansa zosungunuka.
6. Kuyanika
Chomaliza chokonzekera hydroxyethyl cellulose ndi kuyanika. Izi zimachotsa madzi ochulukirapo, kutulutsa mankhwala owuma, a ufa oyenera ntchito zosiyanasiyana.

Kachitidwe:

Ma cellulose otsukidwa a hydroxyethyl amayalidwa pa thireyi zowumitsa kapena kutumizidwa kudzera mumsewu wowumitsa. Kutentha kowumitsa kumayendetsedwa mosamala kuti zisawonongeke, nthawi zambiri kuyambira 50-80 ° C.
Kapenanso, kuyanika kopopera kumatha kugwiritsidwa ntchito poyanika mwachangu komanso moyenera. Poyanika utsi, madzi amadzimadzi a hydroxyethyl cellulose amasinthidwa kukhala madontho abwino ndikuwumitsa mumtsinje wotentha, zomwe zimapangitsa kuti pakhale ufa wabwino.
The zouma mankhwala ndiye mphero kwa ankafuna tinthu kukula ndi kunyamula kuti kusungidwa ndi kugawa.
Kuwongolera Ubwino ndi Ntchito
Panthawi yonse yokonzekera, njira zowongolera bwino zimakhazikitsidwa kuti zitsimikizire kusasinthika komanso mtundu wa hydroxyethyl cellulose. Zofunikira zazikulu monga viscosity, digiri ya m'malo, chinyezi, ndi kukula kwa tinthu timayang'aniridwa nthawi zonse.

Mapulogalamu:

Mankhwala: Amagwiritsidwa ntchito ngati thickening wothandizira, binder, ndi stabilizer mu formulations monga mapiritsi, suspensions, ndi mafuta.
Zodzoladzola: Zimapereka mamasukidwe akayendedwe ndi kapangidwe ka zinthu monga zonona, mafuta odzola, ndi ma shampoos.
Utoto ndi Zopaka: Zimagwira ntchito ngati zowonjezera komanso zosintha za rheology, kuwongolera magwiridwe antchito komanso kukhazikika kwa utoto.
Makampani a Chakudya: Amagwira ntchito ngati thickener, stabilizer, ndi emulsifier mu zakudya zosiyanasiyana.

Kukonzekera kwa cellulose ya hydroxyethyl kumaphatikizapo njira zodziwika bwino zamakina ndi makina omwe cholinga chake ndikusintha mapadi kuti adziwe magulu a hydroxyethyl. Gawo lililonse, kuyambira pakuyeretsa cellulose mpaka kuyanika, ndikofunikira kudziwa mtundu ndi magwiridwe antchito a chinthu chomaliza. Makhalidwe osunthika a Hydroxyethyl cellulose amapangitsa kuti ikhale yofunika kwambiri m'mafakitale ambiri, ndikuwunikira kufunikira kwa njira zopangira zolondola kuti zikwaniritse zofunikira pakugwiritsa ntchito zosiyanasiyana.