Cellulose ether ndi polima yopangidwa kuchokera ku cellulose yachilengedwe kudzera mu kusintha kwa mankhwala. Cellulose ether ndi yochokera ku cellulose yachilengedwe. Kupanga kwa cellulose ether ndi kosiyana ndi ma polima opangidwa. Zinthu zake zofunika kwambiri ndi cellulose, chinthu chachilengedwe cha polymer. Chifukwa cha kapangidwe ka cellulose yachilengedwe, cellulose yokha ilibe mphamvu yochitapo kanthu ndi zinthu zoyeretsera. Komabe, pambuyo pochiza chotupa, ma hydrogen amphamvu pakati pa unyolo wa mamolekyu ndi unyolo amawonongeka, ndipo kutulutsidwa kwa hydroxyl kumayamba kukhala reactive alkali cellulose. Pezani cellulose ether.
Mu matope osakaniza okonzeka, kuchuluka kwa ether ya cellulose kumakhala kochepa kwambiri, koma kumatha kusintha kwambiri magwiridwe antchito a matope onyowa, ndipo ndi chowonjezera chachikulu chomwe chimakhudza magwiridwe antchito a matope. Kusankha koyenera kwa ma ether a cellulose amitundu yosiyanasiyana, kukhuthala kosiyanasiyana, kukula kosiyanasiyana kwa tinthu tating'onoting'ono, madigiri osiyanasiyana a kukhuthala ndi kuchuluka kowonjezera kudzakhala ndi zotsatira zabwino pakuwongolera magwiridwe antchito a matope ouma. Pakadali pano, ma matope ambiri opangidwa ndi miyala ndi pulasitala ali ndi magwiridwe antchito osasunga madzi, ndipo matope amadzi amalekanitsidwa patatha mphindi zochepa atayima.
Kusunga madzi ndi ntchito yofunika kwambiri ya methyl cellulose ether, ndipo ndi ntchito yomwe opanga matope ambiri osakaniza madzi m'nyumba, makamaka omwe ali m'madera akum'mwera komwe kutentha kwambiri, amasamala. Zinthu zomwe zimakhudza momwe matope osakaniza madzi amasungira madzi ndi monga kuchuluka kwa MC yowonjezera, kukhuthala kwa MC, kusalala kwa tinthu tating'onoting'ono ndi kutentha kwa malo ogwiritsidwa ntchito.
Katundu wa ma ether a cellulose amadalira mtundu, chiwerengero ndi kufalikira kwa ma ether. Kugawidwa kwa ma ether a cellulose kumadaliranso mtundu wa ma ether, kuchuluka kwa ether, kusungunuka ndi mawonekedwe ogwirizana nawo. Malinga ndi mtundu wa ma ether omwe ali pa unyolo wa mamolekyu, amatha kugawidwa m'magulu awiri: monoether ndi mixed ether. MC yomwe timagwiritsa ntchito nthawi zambiri ndi monoether, ndipo HPMC ndi mixed ether. Methyl cellulose ether MC ndi chinthu chomwe chimachokera ku gulu la hydroxyl pa glucose unit ya natural cellulose yomwe imalowetsedwa m'malo mwa methoxy. Fomula yomangira ndi [COH7O2(OH)3-h(OCH3)h]x. Gawo la gulu la hydroxyl pa unit limalowetsedwa m'malo mwa gulu la methoxy, ndipo gawo lina limalowetsedwa ndi gulu la hydroxypropyl, kapangidwe kake ndi [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)CH3] n]x Ethyl methyl cellulose ether HEMC, awa ndi mitundu yayikulu yomwe imagwiritsidwa ntchito kwambiri komanso yogulitsidwa pamsika.
Ponena za kusungunuka, ikhoza kugawidwa m'magulu a ionic ndi non-ionic. Ma ether a cellulose osungunuka m'madzi amapangidwa makamaka ndi ma ether awiri a alkyl ndi ma ether a hydroxyalkyl. Ionic CMC imagwiritsidwa ntchito kwambiri mu sopo wopangira, kusindikiza ndi kupaka utoto nsalu, kufufuza chakudya ndi mafuta. Non-ionic MC, HPMC, HEMC, ndi zina zotero zimagwiritsidwa ntchito kwambiri mu zipangizo zomangira, zokutira za latex, mankhwala, mankhwala a tsiku ndi tsiku, ndi zina zotero. Amagwiritsidwa ntchito ngati chokhuthala, chosungira madzi, chokhazikika, chosungunula ndi chopangira filimu.
Kusunga madzi kwa etha ya cellulose: Pakupanga zipangizo zomangira, makamaka matope ouma, etha ya cellulose imagwira ntchito yosasinthika, makamaka pakupanga matope apadera (matope osinthidwa), ndi gawo lofunika kwambiri. Udindo wofunikira wa etha ya cellulose yosungunuka m'madzi mu matope uli ndi mbali zitatu:
1. Kusunga madzi bwino kwambiri
2. Zotsatira pa kusinthasintha kwa matope ndi thixotropy
3. Kuyanjana ndi simenti.
Mphamvu yosungira madzi ya cellulose ether imadalira kuyamwa kwa madzi kwa maziko a chitsulo, kapangidwe ka chitsulo, makulidwe a chitsulo, kufunika kwa madzi kwa chitsulo, ndi nthawi yoyika zinthuzo. Kusunga madzi kwa cellulose ether yokha kumachokera ku kusungunuka ndi kuchepa kwa madzi kwa cellulose ether yokha. Monga tonse tikudziwira, ngakhale kuti cellulose molecular chain ili ndi magulu ambiri a OH omwe amatha kusungunuka, siisungunuka m'madzi, chifukwa kapangidwe ka cellulose kali ndi kristalo wambiri. Mphamvu ya hydration ya magulu a hydroxyl yokha sikokwanira kuphimba ma hydrogen bonds amphamvu ndi mphamvu za van der Waals pakati pa mamolekyu. Chifukwa chake, imangotupa koma siisungunuka m'madzi. Pamene chosinthira chilowetsedwa mu molekyulu ya chitsulo, si chosinthira chokha chomwe chimawononga hydrogen chain, komanso cholumikizira cha hydrogen cholumikizirana chimawonongeka chifukwa cha kugawanika kwa chosinthira pakati pa ma chain oyandikana nawo. Chosinthira chikakhala chachikulu, mtunda pakati pa mamolekyu umakhala waukulu. Mtunda umakhala waukulu. Pamene kuwononga ma hydrogen bond kukukula, cellulose ether imasungunuka m'madzi pambuyo poti cellulose lattice yakula ndipo yankholo lalowa, ndikupanga yankho lolimba kwambiri. Kutentha kukakwera, madzi a polima amachepa, ndipo madzi pakati pa maunyolo amatuluka. Pamene madzi okwanira atuluka, mamolekyu amayamba kusonkhana, kupanga gel yokhala ndi mawonekedwe atatu ndikupindika.
Nthawi yotumizira: Dec-06-2022