Focus on Cellulose ethers

Hydroxypropyl Methyl Cellulose HPMC Properties

Hydroxypropyl methylcellulose HPMC wani nau'in ether ne wanda ba na ionic cellulose ba. Ya bambanta da ionic methyl carboxymethyl cellulose gauraye ether, ba ya amsa da nauyi karafa. Saboda daban-daban rabo na methoxyl abun ciki da hydroxypropyl abun ciki a hydroxypropyl methylcellulose da daban-daban viscosities, akwai da yawa iri da daban-daban kaddarorin, misali, high methoxyl abun ciki da low hydroxypropyl abun ciki Ayyukansa yana kusa da na methyl cellulose, yayin da aikin na ƙananan abun ciki na methoxy da babban abun ciki na hydroxypropyl yana kusa da na hydroxypropyl methyl cellulose. Koyaya, a cikin kowane iri-iri, kodayake ƙaramin rukunin hydroxypropyl ko ƙaramin rukunin methoxyl yana ƙunshe, solubility a cikin abubuwan kaushi na ƙwayoyin cuta ko zafin flocculation a cikin maganin ruwa ya bambanta sosai.
 
1. Solubility na hydroxypropyl methylcellulose
① Solubility na hydroxypropyl methylcellulose a cikin ruwa Hydroxypropyl methylcellulose ne ainihin wani irin methylcellulose modified da propylene oxide (methoxypropylene), don haka shi har yanzu yana da guda Properties kamar yadda methyl cellulose Cellulose yana da irin wannan halaye na ruwan sanyi solubility da ruwan zafi insolubility. Duk da haka, saboda ƙungiyar hydroxypropyl da aka gyara, yawan zafin jiki na gelation a cikin ruwan zafi ya fi girma fiye da na methyl cellulose. Misali, danko na hydroxypropyl methylcellulose mai ruwa bayani tare da 2% methoxy abun ciki maye digiri DS=0.73 da hydroxypropyl abun ciki MS=0.46 samfur ne na 500mpa?s a 20°C, da gel zafin jiki Zai iya kaiwa kusa da 100° C, yayin da methyl cellulose a cikin zafin jiki guda yana da kusan 55 ° C. Dangane da narkar da shi a cikin ruwa, shi ma an inganta shi sosai. Alal misali, da pulverized hydroxypropyl methylcellulose (samfurin da wani barbashi size of 0.2 ~ 0.5mm da 4% mai ruwa bayani danko na 2pa?s a 20 ° C za a iya saya a dakin zafin jiki, shi ne sauƙi mai narkewa a cikin ruwa ba tare da sanyaya. .
 
②Solubility na hydroxypropyl methylcellulose a cikin kwayoyin kaushi Narkewar hydroxypropyl methylcellulose a cikin kwayoyin kaushi kuma ya fi na methylcellulose kyau. Don samfuran sama da 2.1,high danko hydroxypropyl methylcellulosedauke da hydroxypropyl MS = 1.5 ~ 1.8 da methoxy DS = 0.2 ~ 1.0, tare da jimlar digiri na maye gurbin sama da 1.8, yana narkewa a cikin anhydrous methanol da ethanol mafita Medium, da thermoplastic da ruwa mai narkewa. Hakanan yana narkewa a cikin chlorinated hydrocarbons kamar methylene chloride da chloroform, da sauran kaushi kamar acetone, isopropanol da diacetone barasa. Solubility a cikin kwayoyin kaushi yana da kyau fiye da solubility na ruwa.
 
2. Abubuwan da ke shafar danko na hydroxypropyl methylcellulose
Abubuwan Da Ke Tasirin Dankowar Hydroxypropyl Methyl Cellulose Daidaitaccen ƙayyadaddun danko na hydroxypropyl methyl cellulose daidai yake da na sauran ethers cellulose. Ana auna shi a 20 ° C tare da maganin ruwa na 2% a matsayin ma'auni. Danko na samfurin iri ɗaya yana ƙaruwa tare da haɓaka haɓaka. Don samfurori tare da sikelin kwayoyin halitta daban-daban a daidai maida hankali, samfurin tare da babban nauyin kwayoyin yana da danko. Alakarsa da zafin jiki yayi kama da na methyl cellulose. Lokacin da zafin jiki ya tashi, danko ya fara raguwa, amma lokacin da ya kai wani zafin jiki, danko ya tashi ba zato ba tsammani kuma gelation yana faruwa. Zazzabi gel na samfuran ƙarancin danko ya fi girma. yana da girma. Ma'anar gel ɗin sa ba wai kawai yana da alaƙa da danko na ether ba, har ma yana da alaƙa da rabon abun ciki na ƙungiyar metoxyl da ƙungiyar hydroxypropyl a cikin ether da girman jimlar digirin maye gurbin. Dole ne a lura cewa hydroxypropyl methylcellulose shima pseudoplastic ne, kuma maganin sa yana da ƙarfi a cikin zafin jiki ba tare da wani lalacewa a cikin danko ba sai don yuwuwar lalatawar enzymatic.
 
3. Hydroxypropyl methylcellulose yana da tsayayya ga acid da alkali
Hydroxypropyl methylcellulose acid da juriya na alkali Hydroxypropyl methylcellulose gabaɗaya sun tsaya tsayin daka ga acid da alkalis, kuma ba a shafa a cikin kewayon pH 2 ~ 12. Yana iya jure wani adadin haske, Irin su formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, da sauransu. Alkalai irin su caustic soda, caustic potash da ruwan lemun tsami ba su da wani tasiri a kai, amma suna iya kara dankowar maganin, sannan a rage shi a hankali.
 
4. Rashin daidaituwa na hydroxypropyl methylcellulose
Rashin rashin daidaituwa na hydroxypropyl methylcellulose Hydroxypropyl methylcellulose bayani za a iya haɗe shi da mahaɗin polymer mai narkewa da ruwa don zama daidaitaccen bayani kuma bayyananne tare da danko mafi girma. Wadannan mahadi na polymer sun hada da polyethylene glycol, polyvinyl acetate, polysilicon, polymethylvinylsiloxane, hydroxyethyl cellulose, da methyl cellulose. Haɗaɗɗen maɗaukakin ƙwayoyin halitta irin su gumakan arabic, ɗan waken fari, karaya danko, da dai sauransu suma suna da dacewa sosai tare da maganin sa. Hydroxypropyl methylcellulose kuma ana iya haɗa shi da mannitol ester ko sorbitol ester na stearic acid ko palmitic acid, kuma ana iya haɗa shi da glycerin, sorbitol da mannitol, kuma ana iya amfani da waɗannan mahadi azaman hydroxypropyl methylcellulose Plasticizer don cellulose.
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5. Insolubilization da ruwa solubility na hydroxypropyl methylcellulose
Ethers cellulose mai narkewa da ba za a iya narkewa ba na hydroxypropyl methylcellulose za a iya haɗe shi da aldehydes a saman, ta yadda waɗannan ethers masu narkewar ruwa suna haɗe a cikin maganin kuma su zama marasa narkewa a cikin ruwa. Aldehydes da ke yin hydroxypropyl methylcellulose insoluble sun hada da formaldehyde, glioxal, succinic aldehyde, adipaldehyde, da dai sauransu Lokacin amfani da formaldehyde, ya kamata a biya kulawa ta musamman ga darajar pH na maganin, daga cikinsu glioxal yana amsawa da sauri , don haka ana amfani da glioxal a matsayin giciye. wakili a cikin samar da masana'antu. Adadin irin wannan nau'in wakili mai haɗin kai a cikin bayani shine 0.2% ~ 10% na yawan adadin ether, zai fi dacewa 7% ~ 10%, misali, 3.3% ~ 6% na glioxal shine mafi dacewa. Yawan zafin jiki na gabaɗaya shine 0 ~ 30 ℃, kuma lokacin shine 1 ~ 120min. Ana buƙatar ɗaukar matakin haɗin kai a ƙarƙashin yanayin acidic. Gabaɗaya, an fara ƙara maganin tare da acid mai ƙarfi na inorganic ko Organic carboxylic acid don daidaita pH na maganin zuwa kusan 2 ~ 6, zai fi dacewa tsakanin 4 ~ 6, sannan ƙara aldehydes don aiwatar da halayen haɗin kai. Acid da aka yi amfani da shi yana da hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxyacetic acid, succinic acid ko citric acid da dai sauransu, inda tare da formic acid ko acetic acid yana da kyau, kuma formic acid shine mafi kyau. Hakanan za'a iya ƙara acid da aldehyde a lokaci guda don ba da damar maganin ya sami hanyar haɗin kai a cikin kewayon pH da ake so. Ana amfani da wannan amsa sau da yawa a cikin tsarin jiyya na ƙarshe a cikin tsarin shirye-shiryen ethers cellulose. Bayan ether cellulose ba shi da narkewa, ya dace don wankewa da tsaftacewa da ruwa a 20 ~ 25 ° C. Lokacin da ake amfani da samfurin, ana iya ƙara abubuwan alkaline zuwa maganin samfurin don daidaita pH na maganin ya zama alkaline, kuma samfurin zai narke a cikin bayani da sauri. Hakanan ana amfani da wannan hanyar don maganin fim ɗin bayan an yi maganin ether cellulose a cikin fim don sanya shi fim ɗin da ba zai iya narkewa ba.
 
6. Enzyme juriya na hydroxypropyl methylcellulose
Enzyme juriya na hydroxypropyl methylcellulose ne a ka'idar cellulose abubuwan, kamar kowane anhydroglucose kungiyar, idan akwai da tabbaci bonded kungiyar musanya, ba sauki kamuwa da cuta ta microorganisms, amma a gaskiya da ƙãre samfurin Lokacin da maye gurbin darajar ya wuce 1, shi. Hakanan za a lalata su ta hanyar enzymes, wanda ke nufin cewa matakin maye gurbin kowane rukuni akan sarkar cellulose bai isa ba, kuma ƙwayoyin cuta na iya lalata ƙungiyar anhydroglucose da ba a maye gurbin su ba don samar da sukari, azaman abubuwan gina jiki don ƙwayoyin cuta su sha. Saboda haka, idan matakin etherification maye gurbin cellulose ya karu, juriya ga enzymatic yashwa na cellulose ether kuma zai karu. Dangane da rahotanni, a ƙarƙashin yanayin sarrafawa, sakamakon hydrolysis na enzymes, ragowar danko na hydroxypropyl methylcellulose (DS=1.9) shine 13.2%, methylcellulose (DS=1.83) shine 7.3%, methylcellulose (DS=1.66) shine 3.8%, kuma hydroxyethyl cellulose shine 1.7%. Ana iya ganin cewa hydroxypropyl methylcellulose yana da ƙarfin anti-enzyme mai ƙarfi. Saboda haka, mafi kyaun enzyme juriya na hydroxypropyl methylcellulose, haɗe tare da mai kyau dispersibility, thickening da film-forming Properties, ana amfani da ruwa-emulsion coatings, da dai sauransu, kuma kullum ba ya bukatar ƙara preservatives. Duk da haka, don adana dogon lokaci na bayani ko yiwuwar gurɓata daga waje, za'a iya ƙara abubuwan kiyayewa a matsayin kariya, kuma za'a iya ƙayyade zaɓin bisa ga bukatun ƙarshe na bayani. Phenylmercuric acetate da manganese fluorosilicate suna da tasiri masu mahimmanci, amma duk suna da guba, dole ne a biya hankali ga aikin. Gabaɗaya, ana iya ƙara 1 ~ 5mg na phenylmercury acetate zuwa maganin kowace lita na sashi.
 
7. Ayyukan hydroxypropyl methylcellulose membrane
Ayyukan fim ɗin hydroxypropyl methylcellulose Hydroxypropyl methylcellulose yana da kyawawan abubuwan ƙirƙirar fim. Maganin ruwan sa ko maganin kaushi na halitta ana lullube shi akan farantin gilashi, kuma ya zama mara launi da bayyane bayan bushewa. Kuma fim mai tauri. Yana da juriya mai kyau da danshi kuma ya kasance mai ƙarfi a yanayin zafi mai yawa. Idan an ƙara hygroscopic plasticizer, za a iya inganta elongation da sassauci. Dangane da inganta sassauci, masu yin filastik irin su glycerin da sorbitol sun fi dacewa. Gabaɗaya, ƙaddamarwar maganin shine 2% ~ 3%, kuma adadin filastik shine 10% ~ 20% na ether cellulose. Idan abun ciki na plasticizer ya yi yawa, raguwar bushewar colloidal zai faru a babban zafi. Ƙarfin ƙarfin fim ɗin da aka ƙara tare da filastik ya fi girma fiye da haka ba tare da ƙari ba, kuma yana ƙaruwa tare da ƙara yawan adadin da aka ƙara, kuma hygroscopicity na fim din yana ƙaruwa tare da ƙara yawan adadin filastik.


Lokacin aikawa: Dec-19-2022
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