Hydroxypropyl methylcellulosendi mtundu wa ether wosakaniza wa cellulose wosakhala ionic. Mosiyana ndi ether wosakaniza wa ionic methyl carboxymethyl cellulose, suchitapo kanthu ndi zitsulo zolemera. Chifukwa cha kusiyana kosiyana kwa kuchuluka kwa methoxyl ndi kuchuluka kwa hydroxypropyl mu hydroxypropyl methylcellulose ndi kukhuthala kosiyanasiyana, pali mitundu yambiri yokhala ndi makhalidwe osiyanasiyana, mwachitsanzo, kuchuluka kwa methoxyl ndi kuchuluka kwa hydroxypropyl. Kuchita kwake kuli pafupi ndi kwa methyl cellulose, pomwe kugwira ntchito kwa kuchuluka kwa methoxyl ndi kuchuluka kwa hydroxypropyl kuli pafupi ndi kwa hydroxypropyl methyl cellulose. Komabe, mu mtundu uliwonse, ngakhale kuti ndi gulu laling'ono la hydroxypropyl kapena gulu laling'ono la methoxyl lomwe lili, pali kusiyana kwakukulu pakusungunuka kwa organic solvents kapena kutentha kwa flocculation mumadzi.
(1) Kapangidwe ka kusungunuka kwa hydroxypropyl methylcellulose
① Kusungunuka kwa hydroxypropyl methylcellulose m'madziHydroxypropyl methylcelluloseNdi mtundu wa methylcellulose wosinthidwa ndi propylene oxide (methoxy-propylene), kotero udakali ndi makhalidwe ofanana ndi methyl cellulose uli ndi makhalidwe ofanana ndi kusungunuka kwa madzi ozizira komanso kusasungunuka kwa madzi otentha. Komabe, chifukwa cha gulu la hydroxypropyl losinthidwa, kutentha kwake kwa gelation m'madzi otentha kumakhala kokwera kwambiri kuposa kwa methyl cellulose. Mwachitsanzo, kukhuthala kwa hydroxypropyl methylcellulose aqueous solution yokhala ndi 2% methoxy content substitution degree DS=0.73 ndi hydroxypropyl content MS=0.46 ndi 500 mpa·s pa 20°C, ndipo kutentha kwake kwa gel kumatha kufika pafupi ndi 100°C, pomwe methyl cellulose pa kutentha komweko ndi pafupifupi 55°C yokha. Ponena za kusungunuka kwake m'madzi, kwasinthidwanso kwambiri. Mwachitsanzo, hydroxypropyl methylcellulose yophwanyidwa (yokhala ndi mawonekedwe a granular 0.2 ~ 0.5mm pa 20°C yokhala ndi kukhuthala kwa 4% kwa yankho lamadzi la 2pa•s itha kugulidwa kutentha kwa chipinda, imasungunuka mosavuta m'madzi popanda kuzizira.
② Kusungunuka kwa hydroxypropyl methylcellulose mu zosungunulira zachilengedwe, kusungunuka kwa hydroxypropyl methylcellulose mu zosungunulira zachilengedwe ndikwabwino kuposa kwa methylcellulose. Methylcellulose iyenera kukhala ndi digiri yosinthira methoxyl ya 2.1. Zopangidwa pamwambapa, koma zokhala ndi hydroxypropyl MS = 1.5 ~ 1.8 ndi methoxy DS = 0.2 ~ 1.0, hydroxypropyl methylcellulose yokhala ndi kukhuthala kwakukulu yokhala ndi digiri yonse yosinthira pamwamba pa 1.8 imasungunuka mu yankho la anhydrous methanol ndi ethanol, ndipo ili ndi thermos-plasticity ndi madzi osungunuka. Imasungunukanso mu ma hydrocarbons a chlorine monga methylene chloride ndi chloroform, ndi zosungunulira zachilengedwe monga acetone, isopropanol ndi diacetone alcohol. Kusungunuka kwake mu zosungunulira zachilengedwe ndikwabwino kuposa kusungunuka kwa madzi.
(2) Zinthu Zomwe Zimakhudza Kukhuthala kwa Hydroxypropyl Methyl Cellulose Kuzindikira kukhuthala kwa hydroxypropyl methyl cellulose ndi kofanana ndi kwa ma ether ena a cellulose. Kumayesedwa pa 20°C ndi yankho lamadzi la 2% monga muyezo. Kukhuthala kwa chinthu chomwecho kumawonjezeka ndi kuwonjezeka kwa kuchuluka. Kwa zinthu zomwe zimakhala ndi kulemera kosiyanasiyana kwa mamolekyulu pamlingo womwewo, chinthu chomwe chili ndi kulemera kwakukulu kwa mamolekyulu chimakhala ndi kukhuthala kwakukulu. Ubale wake ndi kutentha ndi wofanana ndi wa methyl cellulose. Kutentha kukakwera, kukhuthala kumayamba kutsika, koma kukafika kutentha kwina, kukhuthala kumayamba kukwera mwadzidzidzi ndipo gelation imachitika. Kutentha kwa gel kwa zinthu zokhuthala zochepa kumakhala kwakukulu. Mfundo yake ya gel sikuti imangogwirizana ndi kukhuthala kwa ether, komanso imagwirizana ndi chiŵerengero cha kapangidwe ka gulu la methoxyl ndi gulu la hydroxypropyl mu ether ndi kukula kwa digiri yonse yosinthira. Tiyenera kudziwa kuti hydroxypropyl methylcellulose ndi chinthu chopangidwa ndi pseudoplastic, ndipo yankho lake ndi lokhazikika kutentha kwa chipinda popanda kuwonongeka kwa viscosity kupatula kuthekera kwa kuwonongeka kwa enzymatic.
(3) Kulekerera mchere kwa hydroxypropyl methylcellulose Popeza hydroxypropyl methylcellulose ndi ether yosakhala ionic, siiyikidwa mumadzi, mosiyana ndi ma ether ena a ionic cellulose, monga carboxymethyl Base cellulose, mu yankho kuti igwirizane ndi ma ions achitsulo cholemera ndi precipitate. Mchere wamba monga chloride, bromide, phosphate, nitrate, ndi zina zotero sizingagwedezeke ikawonjezedwa ku yankho lake lamadzi. Komabe, kuwonjezera mchere kumakhudza kutentha kwa flocculation kwa yankho lake lamadzi. Pamene kuchuluka kwa mchere kukukwera, kutentha kwa gel kumachepa. Pamene kuchuluka kwa mchere kuli pansi pa flocculation point, viscosity ya yankho imakonda kuwonjezeka. Chifukwa chake, kuchuluka kwa mchere kumawonjezedwa, pogwiritsira ntchito, kumatha kukulitsa mphamvu. Chifukwa chake, mu ntchito zina, ndi bwino kugwiritsa ntchito chisakanizo cha ether ya cellulose ndi mchere kuposa kuchuluka kwa ether kuti mukwaniritse mphamvu yokhuthala.
(4) Hydroxypropyl methylcellulose acid ndi alkali resistance Hydroxypropyl methylcellulose nthawi zambiri imakhala yokhazikika ku ma acid ndi alkali, ndipo sikhudzidwa ndi pH 2 ~ 12. Imatha kupirira kuchuluka kwa asidi wopepuka, monga formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, ndi zina zotero. Koma asidi wokhuthala umachepetsa kukhuthala. Ma alkali monga caustic soda, caustic potash ndi madzi a laimu sagwira ntchito pa iyo, koma amatha kuwonjezera kukhuthala kwa yankho, kenako nkuchepetsa pang'onopang'ono.
(5) Kusakanikirana kwa hydroxypropyl methylcellulose. Mankhwala a hydroxypropyl methylcellulose amatha kusakanikirana ndi mankhwala a polymer osungunuka m'madzi kuti akhale yankho lofanana komanso lowonekera bwino komanso lokhuthala kwambiri. Mankhwala a polymer awa akuphatikizapo polyethylene glycol, polyvinyl acetate, polysilicone, polymethylvinyl siloxane, hydroxyethyl cellulose, ndi methyl cellulose. Mankhwala achilengedwe okhala ndi mamolekyulu ambiri monga gum arabic, locustbean gum, karaya gum, ndi zina zotero amagwirizananso bwino ndi yankho lake. Hydroxypropyl methylcellulose imatha kusakanikirananso ndi mannitol ester kapena sorbitol ester ya stearic acid kapena palmitic acid, ndipo imatha kusakanikirananso ndi glycerin, sorbitol ndi mannitol, ndipo mankhwalawa angagwiritsidwe ntchito ngati hydroxypropyl methylcellulose Plasticizer ya cellulose.
(6) Chosungunuka m'madzi chosasungunukaethers a celluloseMa hydroxypropyl methylcellulose amatha kugwira ntchito yolumikiza pamwamba ndi aldehydes, kotero kuti ma ether osungunuka m'madzi awa amalowa mu yankho ndikusasungunuka m'madzi. Ma aldehydes omwe amachititsa kuti hydroxypropyl methylcellulose isasungunuke ndi monga formaldehyde, glyoxal, succinic aldehyde, adipaldehyde, ndi zina zotero. Pogwiritsa ntchito formaldehyde, chisamaliro chapadera chiyenera kuperekedwa ku pH ya yankho, lomwe glyoxal imachitapo kanthu mwachangu, kotero glyoxal imagwiritsidwa ntchito kwambiri ngati wothandizira wolumikizirana m'mafakitale. Mlingo wa mtundu uwu wa wothandizira wolumikizirana m'njira ndi 0.2% ~ 10% ya kulemera kwa ether, makamaka 7% ~ 10%, mwachitsanzo, 3.3% ~ 6% ya glyoxal ndiyo yoyenera kwambiri. Nthawi zambiri, kutentha kwa mankhwala ndi 0 ~ 30℃, ndipo nthawi ndi 1 ~ 120min. Kuyanjana kwa crosslinking kuyenera kuchitika pansi pa acidity. Kawirikawiri, pH ya yankho imasinthidwa kufika pa 2~6 powonjezera asidi wamphamvu kapena organic carboxylic acid ku yankho, makamaka pakati pa 4~6, kenako ma aldehydes amawonjezedwa kuti achite crosslinking reaction. Asidi wogwiritsidwa ntchito ali ndi hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxy-acetic acid, succinic acid kapena citric acid etc., pomwe ndi formic acid kapena acetic acid ndibwino, ndipo formic acid ndi yabwino kwambiri. Asidi ndi aldehyde zitha kuwonjezedwanso nthawi imodzi kuti yankho lidutse crosslinking reaction mkati mwa pH yomwe mukufuna. Izi nthawi zambiri zimagwiritsidwa ntchito pomaliza kukonza ma cellulose ethers. Cellulose ether ikatha kusungunuka, ndi bwino kugwiritsa ntchito.
Madzi okwana 20~25℃ otsukira ndi kuyeretsa. Pamene mankhwalawa akugwiritsidwa ntchito, zinthu zamchere zitha kuwonjezeredwa ku yankho la mankhwalawa kuti asinthe pH ya yankholo kuti ikhale yamchere, ndipo mankhwalawa adzasungunuka mwachangu mu yankholo. Njirayi imagwiritsidwanso ntchito pochiza filimuyo pambuyo poti yankho la cellulose ether lapangidwa kukhala filimu kuti likhale filimu yosasungunuka.
(7) Kukana kwa enzyme ya hydroxypropyl methylcellulose mwachiphunzitso ndi zinthu zochokera ku cellulose, monga gulu lililonse la anhydroglucose, ngati pali gulu logwirizana bwino, sizophweka kudwala ndi tizilombo toyambitsa matenda, koma kwenikweni chinthu chomalizidwacho chikapitirira 1, chidzawonongekanso ndi ma enzyme, zomwe zikutanthauza kuti kuchuluka kwa kusintha kwa gulu lililonse pa unyolo wa cellulose sikokwanira, ndipo tizilombo toyambitsa matenda tikhoza kuwonongeka pa gulu la anhydroglucose losasinthidwa kuti lipange shuga, monga zakudya zomwe tizilombo toyambitsa matenda timatha kuyamwa. Chifukwa chake, ngati kuchuluka kwa etherification m'malo mwa cellulose kukuwonjezeka, kukana kwa enzyme est ya cellulose ether kudzawonjezekanso. Malinga ndi malipoti, pansi pa mikhalidwe yolamulidwa, zotsatira za hydrolysis ya ma enzymes opangidwa, kukhuthala kotsalira kwa hydroxypropyl methylcellulose (DS=1.9) ndi 13.2%, methylcellulose (DS=1.83) ndi 7.3%, methylcellulose (DS=1.66) ndi 3.8%, ndipo hydroxyethyl cellulose ndi 1.7%. Zikuoneka kuti hydroxypropyl methylcellulose ili ndi mphamvu yolimbana ndi ma enzyme amphamvu. Chifukwa chake, kukana kwabwino kwa enzyme ya hydroxypropyl methylcellulose, kuphatikiza ndi mphamvu zake zabwino zobalalika, kukhuthala ndi kupanga filimu, imagwiritsidwa ntchito mu zokutira zamadzi-emulsion, ndi zina zotero, ndipo nthawi zambiri sikufunika kuwonjezera zosungira. Komabe, kuti yankho lisungidwe kwa nthawi yayitali kapena kuipitsidwa komwe kungachitike kuchokera kunja, zosungira zitha kuwonjezeredwa ngati njira yodzitetezera, ndipo kusankha kungadziwike malinga ndi zofunikira zomaliza za yankho. Phenylmercuric acetate ndi manganese fluorosilicate ndi zosungira zothandiza, koma zonse zili ndi poizoni, chisamaliro chiyenera kuperekedwa pa ntchitoyo. Kawirikawiri, 1-5mg ya phenylmercury acetate ikhoza kuwonjezeredwa ku yankho pa lita imodzi ya mlingo.
(8) Kuchita bwino kwahydroxypropyl methylcelluloseFilimu ya Hydroxypropyl methylcellulose ili ndi mphamvu zabwino kwambiri zopangira filimu. Yankho lake lamadzi kapena yankho la organic solvent limakutidwa pa mbale yagalasi, ndipo limakhala lopanda utoto komanso lowonekera likauma. Ndipo filimu yolimba. Lili ndi kukana chinyezi bwino ndipo limakhala lolimba kutentha kwambiri. Ngati pulasitiki ya hygroscopic yawonjezeredwa, kutalika kwake ndi kusinthasintha kwake zitha kuwonjezeka. Ponena za kusintha kusinthasintha, mapulasitiki monga glycerin ndi sorbitol ndi oyenera kwambiri. Kawirikawiri, kuchuluka kwa yankho ndi 2% ~ 3%, ndipo kuchuluka kwa pulasitiki ndi 10% ~ 20% ya ether ya cellulose. Ngati kuchuluka kwa pulasitiki kuli kokwera kwambiri, kuchepa kwa madzi m'thupi kumachitika pa chinyezi chambiri. Mphamvu yolimba ya filimu yokhala ndi pulasitiki yowonjezera ndi yayikulu kwambiri kuposa yopanda pulasitiki, ndipo imawonjezeka ndi kuchuluka kwa kuchuluka kowonjezera. Ponena za hygroscopicity ya filimuyo, imawonjezekanso ndi kuchuluka kwa pulasitiki.
Nthawi yotumizira: Epulo-25-2024