Hydroxypropyl methylcellulose (HPMC)ndi etha yosakanizidwa ya cellulose yosungunuka m'madzi yopanda ionic. Mawonekedwe ake ndi oyera mpaka achikasu pang'ono kapena zinthu zopyapyala, zopanda kukoma, zopanda fungo, zopanda poizoni, zokhazikika m'mankhwala, ndipo zimasungunuka m'madzi kuti zipange yankho losalala, lowonekera komanso lokhuthala. Chimodzi mwazinthu zofunika kwambiri za hydroxypropyl methylcellulose pogwiritsidwa ntchito ndikuti imawonjezera kukhuthala kwa madzi. Kukhuthala kwake kumadalira kuchuluka kwa polymerization (DP) ya chinthucho, kuchuluka kwa cellulose ether mu yankho lamadzi, kuchuluka kwa shear rate, ndi kutentha kwa yankho. Ndi zina.
01
Mtundu wamadzimadzi wa yankho la HPMC lamadzimadzi
Kawirikawiri, kupsinjika kwa madzi mu kayendedwe ka shear kungafotokozedwe ngati chifukwa cha kuchuluka kwa shear ƒ(γ) kokha, bola ngati sikudalira nthawi. Kutengera ndi mawonekedwe a ƒ(γ), madzi amatha kugawidwa m'mitundu yosiyanasiyana, yomwe ndi: madzi a Newtonian, madzi otambasuka, madzi a pseudoplastic ndi madzi apulasitiki a Bingham.
Ma ether a cellulose amagawidwa m'magulu awiri: limodzi ndi ether ya cellulose yosakhala ionic ndipo lina ndi ether ya ionic cellulose. Pa rheology ya mitundu iwiriyi ya ma ether a cellulose. SC Naik et al. adachita kafukufuku wofananiza bwino komanso wolinganiza bwino pa mayankho a hydroxyethyl cellulose ndi sodium carboxymethyl cellulose. Zotsatira zake zidawonetsa kuti mayankho onse a non-ionic cellulose ether ndi mayankho a ionic cellulose ether anali pseudoplastic. Ma flow, mwachitsanzo omwe si a Newtonian flows, amafikira madzi a Newtonian okha pamlingo wotsika kwambiri. Pseudoplasticity ya yankho la hydroxypropyl methylcellulose imagwira ntchito yofunika kwambiri pakugwiritsa ntchito. Mwachitsanzo, ikagwiritsidwa ntchito mu zokutira, chifukwa cha mawonekedwe a shear thinning a aqueous solutions, viscosity ya yankho imachepa ndi kuwonjezeka kwa shear rate, zomwe zimapangitsa kuti tinthu ta pigment tifalikire mofanana, komanso kumawonjezera kusinthasintha kwa zokutira. Zotsatira zake zimakhala zazikulu kwambiri; pomwe zili zopumula, viscosity ya yankho ndi yayikulu, zomwe zimalepheretsa bwino kuyika kwa tinthu ta pigment mu zokutira.
02
Njira Yoyesera ya HPMC Viscosity
Chizindikiro chofunikira poyesa kuchuluka kwa hydroxypropyl methylcellulose ndi kukhuthala koonekera kwa yankho lamadzi. Njira zoyezera kukhuthala koonekera nthawi zambiri zimaphatikizapo njira ya kukhuthala kwa capillary, njira ya kukhuthala kozungulira ndi njira ya kukhuthala kwa mpira wogwa.
komwe: ndi kukhuthala koonekera, mPa s; K ndi viscometer yosasinthika; d ndi kuchuluka kwa chitsanzo cha yankho pa 20/20°C; t ndi nthawi yoti yankho lidutse pamwamba pa viscometer kupita pansi, s; Nthawi yomwe mafuta wamba amadutsa mu viscometer imayesedwa.
Komabe, njira yoyezera pogwiritsa ntchito capillary viscometer ndi yovuta kwambiri. Kukhuthala kwa ambiriethers a celluloseN'zovuta kuzifufuza pogwiritsa ntchito capillary viscometer chifukwa njirazi zili ndi zinthu zochepa zomwe sizisungunuka zomwe zimangopezeka pamene capillary viscometer yatsekedwa. Chifukwa chake, opanga ambiri amagwiritsa ntchito rotational viscometers kuti azitha kuwongolera mtundu wa hydroxypropyl methylcellulose. Brookfield viscometers nthawi zambiri amagwiritsidwa ntchito m'maiko akunja, ndipo NDJ viscometers zimagwiritsidwa ntchito ku China.
03
Zinthu zomwe zimakhudza kukhuthala kwa HPMC
3.1 Ubale ndi kuchuluka kwa kusonkhana
Ngati magawo ena sakusintha, kukhuthala kwa yankho la hydroxypropyl methylcellulose kumakhala kofanana ndi kuchuluka kwa polymerization (DP) kapena kulemera kwa molekyulu kapena kutalika kwa unyolo wa molekyulu, ndipo kumawonjezeka ndi kuchuluka kwa kuchuluka kwa polymerization. Zotsatirazi zimakhala zomveka bwino pankhani ya polymerization yochepa kuposa pankhani ya polymerization yayikulu.
3.2 Ubale pakati pa kukhuthala ndi kukhudzika
Kukhuthala kwa hydroxypropyl methylcellulose kumawonjezeka ndi kuchuluka kwa mankhwala mu yankho lamadzi. Ngakhale kusintha pang'ono kwa kuchuluka kungayambitse kusintha kwakukulu kwa kukhuthala. Ndi kukhuthala kodziwika bwino kwa hydroxypropyl methylcellulose Zotsatira za kusintha kwa kuchuluka kwa yankho pa kukhuthala kwa yankho zimakhala zoonekeratu.
3.3 Ubale pakati pa kukhuthala ndi kuchuluka kwa kumeta
Madzi a Hydroxypropyl methylcellulose ali ndi mphamvu yochepetsa kuuma kwa shear. Hydroxypropyl methylcellulose ya viscosity yosiyana imakonzedwa mu 2% yamadzi, ndipo viscosity yake pamlingo wosiyana wa shear imayesedwa motsatana. Zotsatira zake ndi izi Monga momwe zasonyezedwera pachithunzichi. Pamlingo wotsika wa shear, viscosity ya hydroxypropyl methylcellulose solution sinasinthe kwambiri. Ndi kuwonjezeka kwa shear rate, viscosity ya hydroxypropyl methylcellulose solution yokhala ndi viscosity yochuluka ya nominal inachepa moonekeratu, pomwe yankho lokhala ndi viscosity yotsika silinachepe moonekeratu.
3.4 Ubale pakati pa kukhuthala ndi kutentha
Kukhuthala kwa yankho la hydroxypropyl methylcellulose kumakhudzidwa kwambiri ndi kutentha. Pamene kutentha kukukwera, kukhuthala kwa yankho kumachepa. Monga momwe chithunzichi chikusonyezera, limakonzedwa kukhala yankho lamadzi lokhala ndi kuchuluka kwa 2%, ndipo kusintha kwa kukhuthala ndi kuwonjezeka kwa kutentha kumayesedwa.
3.5 Zinthu zina zomwe zimakhudza
Kukhuthala kwa yankho lamadzi la hydroxypropyl methylcellulose kumakhudzidwanso ndi zowonjezera mu yankho, pH ya yankho, ndi kuwonongeka kwa tizilombo toyambitsa matenda. Nthawi zambiri, kuti mupeze magwiridwe antchito abwino a kukhuthala kapena kuchepetsa mtengo wogwiritsira ntchito, ndikofunikira kuwonjezera zinthu zosinthira rheology, monga dongo, dongo losinthidwa, ufa wa polymer, starch ether ndi aliphatic copolymer, ku yankho lamadzi la hydroxypropyl methylcellulose., ndipo ma electrolyte monga chloride, bromide, phosphate, nitrate, ndi zina zotero amathanso kuwonjezeredwa ku yankho lamadzi. Zowonjezera izi sizingokhudza mphamvu ya kukhuthala kwa yankho lamadzi, komanso zimakhudzanso mphamvu zina zogwiritsira ntchito za hydroxypropyl methylcellulose monga kusunga madzi., kukana kutsika, ndi zina zotero.
Kukhuthala kwa madzi a hydroxypropyl methylcellulose sikukhudzidwa ndi asidi ndi alkali, ndipo nthawi zambiri kumakhala kokhazikika pakati pa 3 mpaka 11. Kumatha kupirira kuchuluka kwa ma asidi ofooka, monga formic acid, acetic acid, phosphoric acid, boric acid, citric acid, ndi zina zotero. Komabe, asidi wokhuthala amachepetsa kukhuthala. Koma caustic soda, potassium hydroxide, laimu water, ndi zina zotero sizimakhudza kwambiri. Poyerekeza ndi ma cellulose ether ena,hydroxypropyl methylcelluloseMadzi amadzi ali ndi kukhazikika kwabwino kwa maantibayotiki, chifukwa chachikulu ndichakuti hydroxypropyl methylcellulose ili ndi magulu osagwirizana ndi madzi okhala ndi digiri yayikulu yosinthira komanso choletsa cha steric cha magulu. Komabe, popeza kuti kusintha kwa zinthu nthawi zambiri sikofanana, gawo losasinthidwa la anhydroglucose limawonongeka mosavuta ndi tizilombo toyambitsa matenda, zomwe zimapangitsa kuti mamolekyu a cellulose ether awonongeke komanso kusweka kwa unyolo. Kuchita bwino kwake ndikuti kukhuthala kwa madzi amadzi kumachepa. Ngati kuli kofunikira kusunga madzi a hydroxypropyl methylcellulose kwa nthawi yayitali, tikulimbikitsidwa kuwonjezera kuchuluka kwa mankhwala ophera bowa kuti kukhuthala kusasinthe kwambiri. Mukasankha mankhwala ophera bowa, zosungira kapena fungicides, muyenera kusamala za chitetezo, ndikusankha zinthu zomwe si poizoni m'thupi la munthu, zomwe zili ndi mphamvu zokhazikika komanso zopanda fungo, monga DOW Chem's AMICAL fungicides, zosungira za CANGUARD64, zotetezera za FUELSAVER ndi zinthu zina. Zitha kukhala ndi gawo lofanana.
Nthawi yotumizira: Epulo-28-2024