Hydroxypropyl methylcellulosewani nau'in ether ne na gaurayen cellulose wanda ba ionic ba. Ba kamar ionic methyl carboxymethyl cellulose gauraye ether ba, ba ya amsawa da ƙarfe masu nauyi. Saboda bambancin rabo na abun ciki na methoxyl da abun ciki na hydroxypropyl a cikin hydroxypropyl methylcellulose da kuma bambance-bambancen viscosities, akwai nau'ikan iri da yawa waɗanda ke da halaye daban-daban, misali, babban abun ciki na methoxyl da ƙarancin abun ciki na hydroxypropyl Aikinsa yana kusa da na methyl cellulose, yayin da aikin ƙarancin abun ciki na methoxyl da babban abun ciki na hydroxypropyl yana kusa da na hydroxypropyl methyl cellulose. Duk da haka, a cikin kowane iri, kodayake ƙaramin adadin rukunin hydroxypropyl ko ƙaramin adadin rukunin methoxyl ne kawai aka ƙunsa, akwai manyan bambance-bambance a cikin narkewar abubuwa masu narkewa a cikin sinadarai na halitta ko zafin flocculation a cikin ruwan.
(1) Sifofin narkewar hydroxypropyl methylcellulose
① Narkewar hydroxypropyl methylcellulose a cikin ruwaHydroxypropyl methylcelluloseA zahiri wani nau'in methylcellulose ne da aka gyara ta hanyar propylene oxide (methoxy-propylene), don haka har yanzu yana da irin waɗannan halaye kamar methyl cellulose yana da halaye iri ɗaya na narkewar ruwan sanyi da rashin narkewar ruwan zafi. Duk da haka, saboda ƙungiyar hydroxypropyl da aka gyara, zafin gelation ɗinsa a cikin ruwan zafi ya fi na methyl cellulose girma. Misali, ɗankowar ruwan hydroxypropyl methylcellulose tare da digiri na maye gurbin abun ciki na methoxy 2% DS=0.73 da hydroxypropyl abun ciki MS=0.46 shine 500 mpa·s a 20°C, kuma zafin gel ɗinsa Yana iya kaiwa kusa da 100°C, yayin da methyl cellulose a zafin iri ɗaya yake kusan 55°C kawai. Dangane da narkewar sa a cikin ruwa, an kuma inganta shi sosai. Misali, ana iya siyan hydroxypropyl methylcellulose mai narkewa (siffar granular 0.2 ~ 0.5mm a 20°C tare da danko na ruwa 4% na 2pa•s a zafin ɗaki, yana narkewa cikin sauƙi a cikin ruwa ba tare da sanyaya ba.
② Narkewar hydroxypropyl methylcellulose a cikin sinadaran sinadarai na halitta, narkewar hydroxypropyl methylcellulose a cikin sinadaran sinadarai na halitta shi ma ya fi na methylcellulose kyau. Methylcellulose yana buƙatar samun matakin maye gurbin methoxyl na 2.1 Kayayyakin da ke sama, amma suna ɗauke da hydroxypropyl MS=1.5~1.8 da methoxy DS=0.2~1.0, hydroxypropyl methylcellulose mai yawan danko tare da cikakken matakin maye gurbin sama da 1.8 yana narkewa a cikin methanol da ethanol mai hana ruwa, kuma yana da thermos-plasticity da kuma narkewar ruwa. Hakanan yana narkewa a cikin hydrocarbons masu chlorine kamar methylene chloride da chloroform, da kuma sinadaran sinadarai na halitta kamar acetone, isopropanol da diacetone alcohol. Narkewar sa a cikin sinadaran sinadarai na halitta ya fi narkewar ruwa kyau.
(2) Abubuwan da ke Tasirin Dankowar Hydroxypropyl Methyl Cellulose. Daidaita dankowar hydroxypropyl methyl cellulose iri ɗaya ne da na sauran cellulose ethers. Ana auna shi a 20°C da ruwan da aka tace kashi 2% a matsayin ma'auni. Dankowar samfurin iri ɗaya yana ƙaruwa tare da ƙaruwar maida hankali. Ga samfuran da ke da nauyin kwayoyin halitta daban-daban a daidai wannan maida hankali, samfurin da ke da nauyin kwayoyin halitta mafi girma yana da dankowa mafi girma. Alaƙarsa da zafin jiki yayi kama da na methyl cellulose. Lokacin da zafin jiki ya tashi, dankowa ya fara raguwa, amma lokacin da ya kai wani zafin jiki, dankowa ya tashi kwatsam kuma ya faru. Zafin gel na samfuran ƙarancin dankowa ya fi girma. Yana da yawa. Batun gel ɗinsa ba wai kawai yana da alaƙa da dankowar ether ba, har ma yana da alaƙa da rabon abun da ke ciki na ƙungiyar methoxyl da ƙungiyar hydroxypropyl a cikin ether da girman matakin maye gurbin gabaɗaya. Dole ne a lura cewa hydroxypropyl methylcellulose shima pseudoplastic ne, kuma maganinsa yana da karko a zafin ɗaki ba tare da wani lalacewar danko ba sai dai yiwuwar lalacewar enzymatic.
(3) Juriyar gishirin hydroxypropyl methylcellulose Tunda hydroxypropyl methylcellulose ba ionic ba ne, ba a yin ionized a cikin ruwa, ba kamar sauran ionic cellulose ethers ba, kamar carboxymethyl Base cellulose, a cikin maganin don yin amsawa da ions na ƙarfe masu nauyi da precipitate. Gishiri na gabaɗaya kamar chloride, bromide, phosphate, nitrate, da sauransu ba za su zube ba lokacin da aka ƙara su a cikin maganin ruwa. Duk da haka, ƙarin gishiri yana da ɗan tasiri akan zafin flocculation na maganin ruwa. Lokacin da yawan gishirin ya ƙaru, zafin gel ɗin yana raguwa. Lokacin da yawan gishirin ya kasance ƙasa da wurin flocculation, ɗanko na maganin yana ƙaruwa. Saboda haka, ana ƙara wani adadin gishiri, a cikin aikace-aikacen, yana iya samun tasirin kauri cikin tattalin arziki. Saboda haka, a wasu aikace-aikacen, ya fi kyau a yi amfani da cakuda cellulose ether da gishiri fiye da babban yawan maganin ether don cimma tasirin kauri.
(4) Hydroxypropyl methylcellulose acid da juriyar alkali Hydroxypropyl methylcellulose gabaɗaya yana da daidaito ga acid da alkalis, kuma ba ya shafar pH 2~12. Yana iya jure wa wani adadin acid mai sauƙi, Kamar formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, da sauransu. Amma acid mai ƙarfi yana da tasirin rage danko. Alkalis kamar caustic soda, caustic potash da ruwan lemun tsami ba su da wani tasiri a kansa, amma suna iya ƙara danko na maganin, sannan a hankali su rage shi.
(5) Rashin daidaituwar sinadarin hydroxypropyl methylcellulose Ana iya haɗa sinadarin Hydroxypropyl methylcellulose da sinadaran polymer masu narkewa cikin ruwa don su zama mafita iri ɗaya da haske tare da ɗanko mai yawa. Waɗannan sinadaran polymer sun haɗa da polyethylene glycol, polyvinyl acetate, polysilicone, polymethylvinyl siloxane, hydroxyethyl cellulose, da methyl cellulose. Hakanan akwai sinadarai masu ƙarfi na halitta kamar gum arabic, locust bean gum, karaya gum, da sauransu. Hakanan ana iya haɗa Hydroxypropyl methylcellulose 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.
(6) Ruwan da ba ya narkewa cikin ruwa mai narkewaƙwayoyin cellulosena hydroxypropyl methylcellulose na iya yin haɗin saman da aldehydes, ta yadda waɗannan ethers masu narkewa cikin ruwa za su shiga cikin maganin kuma su zama ba sa narkewa a cikin ruwa. Aldehydes da ke yin hydroxypropyl methylcellulose wanda ba ya narkewa sun haɗa da formaldehyde, glyoxal, succinic aldehyde, adipaldehyde, da sauransu. Lokacin amfani da formaldehyde, ya kamata a ba da kulawa ta musamman ga ƙimar pH na maganin, daga cikinsu glyoxal yana amsawa da sauri, don haka ana amfani da glyoxal a matsayin wakili mai haɗa haɗin gwiwa a cikin masana'antu. Yawan wannan nau'in wakili mai haɗa haɗin gwiwa a cikin maganin shine 0.2% ~ 10% na nauyin ether, zai fi dacewa 7% ~ 10%, misali, 3.3% ~ 6% na glyoxal shine mafi dacewa. Gabaɗaya, zafin magani shine 0 ~ 30℃, kuma lokacin shine minti 1 ~ 120. Ana buƙatar aiwatar da haɗin haɗin gwiwa a ƙarƙashin yanayin acidic. Gabaɗaya, ana daidaita pH na maganin zuwa kimanin 2-6 ta hanyar ƙara acid mai ƙarfi ko kuma acid carboxylic na halitta a cikin maganin, zai fi dacewa tsakanin 4-6, sannan a ƙara aldehydes don aiwatar da haɗin gwiwa. Acid ɗin da aka yi amfani da shi yana da hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxy-acetic acid, succinic acid ko citric acid da sauransu, inda ake ba da shawarar yin amfani da formic acid ko acetic acid, kuma formic acid shine mafi kyau. Haka kuma ana iya ƙara acid da aldehyde a lokaci guda don ba da damar maganin ya sami haɗin gwiwa a cikin kewayon pH da ake so. Sau da yawa ana amfani da wannan haɗin gwiwa a cikin tsarin magani na ƙarshe a cikin tsarin shirya cellulose ethers. Bayan cellulose ether ya zama ba ya narkewa, yana da sauƙin amfani.
Ruwa mai zafi 20-25℃ don wankewa da tsarkakewa. Lokacin da ake amfani da samfurin, ana iya ƙara abubuwan alkaline a cikin maganin samfurin don daidaita pH na maganin ya zama alkaline, kuma samfurin zai narke a cikin maganin da sauri. Wannan hanyar kuma tana aiki ga maganin fim ɗin bayan an yi maganin cellulose ether zuwa fim don ya zama fim mara narkewa.
(7) Juriyar enzyme na hydroxypropyl methylcellulose a ka'ida ta samo asali ne daga cellulose, kamar kowace ƙungiyar anhydroglucose, idan akwai ƙungiyar maye gurbin da ta haɗu sosai, ba abu ne mai sauƙi a kamu da ƙwayoyin cuta ba, amma a zahiri samfurin da aka gama. Lokacin da ƙimar maye gurbin ta wuce 1, enzymes kuma za su lalata shi, wanda ke nufin cewa matakin maye gurbin kowace ƙungiya akan sarkar cellulose bai yi daidai ba, kuma ƙwayoyin cuta na iya lalacewa akan ƙungiyar anhydroglucose da ba a maye gurbinta ba don samar da sukari, kamar yadda abubuwan gina jiki don ƙwayoyin cuta su sha. Saboda haka, idan matakin maye gurbin cellulose na etherification ya ƙaru, juriya ga lalacewar enzymatic na cellulose ether shima zai ƙaru. A cewar rahotanni, a ƙarƙashin yanayi mai sarrafawa, sakamakon hydrolysis na enzymes da aka yi, 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%. Za a iya ganin cewa hydroxypropyl methylcellulose yana da ƙarfin hana enzyme. Saboda haka, ana amfani da kyakkyawan juriyar enzyme na hydroxypropyl methylcellulose, tare da kyawawan halayensa na warwatsewa, kauri da samar da fim, a cikin murfin emulsion na ruwa, da sauransu, kuma gabaɗaya ba ya buƙatar ƙara abubuwan kiyayewa. Duk da haka, don adana maganin na dogon lokaci ko yiwuwar gurɓatawa daga waje, ana iya ƙara abubuwan kiyayewa a matsayin kariya, kuma ana iya tantance zaɓin bisa ga buƙatun ƙarshe na maganin. Phenylmercuric acetate da manganese fluorosilicate magunguna ne masu tasiri na kiyayewa, amma duk suna da Guba, dole ne a kula da aikin. Gabaɗaya, ana iya ƙara 1 ~ 5mg na phenylmercury acetate zuwa maganin a kowace lita na maganin.
(8) Aikinhydroxypropyl methylcellulosefim Hydroxypropyl methylcellulose yana da kyawawan halaye na samar da fim. Maganin ruwa ko maganin narkewar sinadarai na halitta an shafa shi a kan farantin gilashi, kuma yana zama mara launi da haske bayan bushewa. Kuma fim mai tauri. Yana da juriyar danshi mai kyau kuma yana da ƙarfi a yanayin zafi mai yawa. Idan aka ƙara plasticizer mai hygroscopic, ana iya ƙara tsayinsa da sassaucinsa. Dangane da inganta sassauci, plasticizers kamar glycerin da sorbitol sune mafi dacewa. Gabaɗaya, yawan maganin shine 2% ~ 3%, kuma adadin plasticizer shine 10% ~ 20% na cellulose ether. Idan abun da ke cikin plasticizer ya yi yawa, raguwar bushewar colloidal zai faru a lokacin zafi mai yawa. Ƙarfin juriya na fim ɗin tare da plasticizer ya fi girma fiye da wanda ba tare da plasticizer ba, kuma yana ƙaruwa tare da ƙaruwar adadin da aka ƙara. Dangane da hygroscopicity na fim ɗin, yana ƙaruwa tare da ƙaruwar adadin plasticizer.
Lokacin Saƙo: Afrilu-25-2024