Hydroxypropyl methylcellulose ndi mtundu wa ether wosakaniza wa cellulose wosakhala ionic. Mosiyana ndi ether wosakaniza wa ionic methyl carboxymethyl cellulose, sichitapo 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 kuchuluka kwa methoxyl ndi kuchuluka kwa hydroxypropyl kuli pafupi ndi kwa hydroxypropyl methyl cellulose. Komabe, mu mtundu uliwonse, ngakhale kuti pali gulu laling'ono la hydroxypropyl kapena gulu laling'ono la methoxyl, pali kusiyana kwakukulu pakusungunuka mu organic solvents kapena kutentha kwa flocculation mumadzi.
(1) Kapangidwe ka kusungunuka kwa hydroxypropyl methylcellulose
①Kusungunuka kwa hydroxypropyl methylcellulose m'madzi Hydroxypropyl methylcellulose kwenikweni ndi mtundu wa methylcellulose wosinthidwa ndi propylene oxide (methoxypropylene), kotero ikadali ndi makhalidwe ofanana ndi methyl cellulose Cellulose ili 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 kwakukulu 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 pafupifupi 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 (yooneka ngati granular shape 0.2 ~ 0.5mm pa 20°C yokhala ndi 4% aqueous solution viscosity ya 2pa•s ingathe kugulidwa pa kutentha kwa chipinda, imasungunuka mosavuta m'madzi popanda kuzizira.
②Kusungunuka kwa hydroxypropyl methylcellulose mu zosungunulira zachilengedwe Kusungunuka kwa hydroxypropyl methylcellulose mu zosungunulira zachilengedwe ndikwabwino kuposa kwa methylcellulose. Pazinthu zomwe zili pamwambapa 2.1, hydroxypropyl methylcellulose yokhala ndi viscosity yayikulu yokhala ndi hydroxypropyl MS=1.5~1.8 ndi methoxy DS=0.2~1.0, yokhala ndi digiri yonse yosinthira pamwamba pa 1.8, imasungunuka mu anhydrous methanol ndi ethanol solutions Yapakatikati, komanso thermoplastic komanso yosungunuka m'madzi. Imasungunukanso mu chlorine hydrocarbons 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 methylcellulose Kuzindikira kukhuthala kwa hydroxypropyl methylcellulose kuli kofanana ndi ma ether ena a cellulose, ndipo kumayesedwa pa 20°C ndi yankho lamadzi la 2% monga muyezo. Kukhuthala kwa chinthu chomwecho kumawonjezeka ndi kuwonjezeka kwa kuchuluka. Pazinthu zomwe zili ndi kulemera kosiyanasiyana kwa mamolekyulu pamlingo womwewo, chinthucho chokhala ndi kulemera kwakukulu kwa mamolekyulu chimakhala ndi kukhuthala kwakukulu. Ubale wake ndi kutentha ndi wofanana ndi wa methyl cellulose. Kutentha kukakwera, kukhuthala kumayamba kuchepa, 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 methoxyl group ndi hydroxypropyl group mu ether ndi kukula kwa digiri yonse yosinthira. Tiyenera kudziwa kuti hydroxypropyl methylcellulose ndi pseudoplastic, ndipo yankho lake ndi lokhazikika kutentha kwa chipinda popanda kuwonongeka kulikonse mu kukhuthala kupatula kuthekera kwa kuwonongeka kwa enzymatic.
(3) Kulekerera mchere kwa hydroxypropyl methylcellulose Popeza hydroxypropyl methylcellulose ndi ether yosakhala ionic, siimasungunuka m'madzi, mosiyana ndi ma ether ena a ionic cellulose. Mwachitsanzo, carboxymethyl cellulose imagwira ntchito ndi ma ayoni achitsulo cholemera ndipo imatuluka mu yankho. Mchere wamba monga chloride, bromide, phosphate, nitrate, ndi zina zotero sizimasungunuka ikawonjezedwa ku yankho lake lamadzi. Komabe, kuwonjezera mchere kumakhudza kutentha kwa flocculation kwa yankho lake lamadzi. Pamene kuchuluka kwa mchere kumawonjezeka, kutentha kwa gel kumachepa. Pamene kuchuluka kwa mchere kuli pansi pa flocculation point, kukhuthala kwa yankho kumawonjezeka. Chifukwa chake, kuchuluka kwa mchere kumawonjezedwa. , pogwiritsira ntchito, kumatha kukhuthala kwambiri. Chifukwa chake, nthawi zina, ndi bwino kugwiritsa ntchito chisakanizo cha ether ya cellulose ndi mchere kuposa kuchuluka kwa ether kuti mukwaniritse kuchuluka kwa kukhuthala.
(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 ma Light acid, monga formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, ndi zina zotero. Koma concentrated acid imachepetsa kukhuthala. Ma alkali monga caustic soda, caustic potash ndi laimu water sagwira ntchito pa iyo, koma amatha kuwonjezera kukhuthala kwa yankho, kenako nkuchepetsa pang'onopang'ono.
(5) Kugwirizana kwa hydroxypropyl methylcellulose. Yankho la hydroxypropyl methylcellulose likhoza kusakanikirana ndi mankhwala a polymer osungunuka m'madzi kuti apange yankho lofanana komanso lowonekera bwino komanso lokhuthala kwambiri. Mankhwala a polymer awa akuphatikizapo polyethylene glycol, polyvinyl acetate, polysilicone, polymethylvinylsiloxane, 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 ingathenso kusakanikirana ndi mannitol ester kapena sorbitol ester ya stearic acid kapena palmitic acid, ndipo ingathenso kusakanikirana ndi glycerin, sorbitol ndi mannitol, ndipo mankhwalawa angagwiritsidwe ntchito ngati hydroxypropyl methylcellulose Plasticizer ya cellulose.
(6) Ma ether a cellulose osasungunuka m'madzi a hydroxypropyl methylcellulose amatha kuchita kulumikiza pamwamba ndi aldehydes, kotero kuti ma ether osungunuka m'madzi awa amalowetsedwa 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. Kuchuluka kwa mtundu uwu wa wothandizira wolumikizirana m'madzi 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, yankholo limawonjezeredwa koyamba ndi inorganic strong acid kapena organic carboxylic acid kuti lisinthe pH ya yankholo kufika pa 2 ~ 6, makamaka pakati pa 4 ~ 6, kenako limawonjezeredwa aldehydes kuti lichite cross-linking reaction. Asidi wogwiritsidwa ntchito ali ndi hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxyacetic 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 kuwonjezeredwanso nthawi imodzi kuti yankholo lichite cross-linking reaction mkati mwa pH yomwe mukufuna. Izi nthawi zambiri zimagwiritsidwa ntchito pomaliza njira yochizira pokonzekera 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 M'malingaliro, zinthu zochokera ku cellulose, monga gulu logwirizana bwino pa gulu lililonse la anhydroglucose, sizikhudzidwa ndi kuwonongeka kwa tizilombo toyambitsa matenda, koma kwenikweni, pamene mtengo wosinthira wa chinthu chomalizidwa upitirira 1, udzawonongekanso 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. Shuga amapangidwa ndi kuyamwa ngati michere ya tizilombo toyambitsa matenda. Chifukwa chake, ngati kuchuluka kwa etherification m'malo mwa cellulose kukuwonjezeka, kukana kwa ezymatic ester ya cellulose ether kudzawonjezekanso. Malinga ndi malipoti, pansi pa mikhalidwe yolamulidwa, zotsatira za hydrolysis ya ma enzyme, 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) Kagwiridwe ka ntchito ka filimu ya hydroxypropyl methylcellulose Hydroxypropyl methylcellulose ili ndi mphamvu zabwino kwambiri zopanga filimu. Yankho lake lamadzimadzi kapena yankho la organic solvent limakutidwa pa mbale yagalasi, ndipo limakhala lomasuka likauma. Filimu ya utoto, yowonekera bwino komanso yolimba. Ili ndi kukana chinyezi bwino ndipo imakhalabe yolimba 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 kowonjezeredwa. Ponena za hygroscopicity ya filimuyo, imawonjezekanso ndi kuchuluka kwa pulasitiki.
Nthawi yotumizira: Disembala-20-2022