Cellulose ether shine kalma na gaba ɗaya don jerin samfurori da aka samar ta hanyar amsawar alkali cellulose da etherifying wakili a ƙarƙashin wasu yanayi.Alkali cellulose an maye gurbinsu da daban-daban etherifying jamiái don samun daban-daban cellulose ethers.Dangane da kaddarorin ionization na masu maye, ana iya raba ethers cellulose zuwa kashi biyu: ionic (kamar carboxymethyl cellulose) da nonionic (kamar methyl cellulose).Dangane da nau'in maye gurbin, ana iya raba ether cellulose zuwa monoether (kamar methyl cellulose) da ether gauraye (kamar hydroxypropyl methyl cellulose).A cewar daban-daban solubility, shi za a iya raba zuwa ruwa solubility (kamar hydroxyethyl cellulose) da Organic sauran ƙarfi solubility (kamar ethyl cellulose).Turmi-busasshen da aka haɗe shine cellulose mai narkewa da ruwa, kuma cellulose mai narkewar ruwa ya kasu zuwa nau'in nan take da nau'in jinkiri-nau'i mai jinkiri.
Hanyar aikin ether cellulose a cikin turmi shine kamar haka:
(1) Bayan da cellulose ether a cikin turmi aka narkar da a cikin ruwa, da tasiri da kuma uniform rarraba siminti abu a cikin tsarin da aka tabbatar saboda da surface aiki, da kuma cellulose ether, a matsayin m colloid, "nannade" m. barbashi da kuma wani Layer na fim mai shafawa yana samuwa a samansa na waje, wanda ke sa tsarin turmi ya zama mafi kwanciyar hankali, kuma yana inganta yawan ruwa na turmi yayin aikin hadawa da kuma santsin ginin.
(2) Saboda halayensa na tsarin kwayoyin halitta, maganin cellulose ether yana sa danshi a cikin turmi ba shi da sauƙi a rasa, kuma a hankali ya sake shi na dogon lokaci, yana ba da turmi tare da kyakkyawan ruwa da aiki.
1. Methylcellulose: (MC)
Bayan an yi amfani da auduga mai ladabi tare da alkali, ana samar da ether cellulose ta hanyar jerin halayen da methane chloride a matsayin wakili na etherification.Gabaɗaya, matakin maye gurbin shine 1.6 ~ 2.0, kuma solubility shima ya bambanta da digiri daban-daban na maye gurbin.Nasa ne ga wadanda ba ionic cellulose ether.
(1) Methylcellulose yana narkewa a cikin ruwan sanyi, kuma zai yi wuya a narke cikin ruwan zafi.Maganin ruwan sa yana da ƙarfi sosai a cikin kewayon pH = 3 ~ 12.Yana da kyau dacewa tare da sitaci, guar danko, da dai sauransu da yawa surfactants.Lokacin da zafin jiki ya kai ga zafin jiki na gelation, gelation yana faruwa.
(2) Riƙewar ruwa na methyl cellulose ya dogara da adadin adadinsa, danko, fineness barbashi da rushewar kudi.Gabaɗaya, idan adadin ƙari yana da girma, ƙarancin ƙarancin ƙanƙara ne, kuma danko yana da girma, yawan riƙe ruwa yana da girma.Daga cikin su, adadin ƙarawa yana da tasiri mafi girma a kan yawan ajiyar ruwa, kuma matakin danko ba daidai ba ne kai tsaye zuwa matakin yawan ruwa.A rushe kudi yafi dogara a kan mataki na surface gyara na cellulose barbashi da barbashi fineness.Daga cikin ethers cellulose da ke sama, methyl cellulose da hydroxypropyl methyl cellulose suna da ƙimar riƙe ruwa mafi girma.
(3) Canje-canje a cikin zafin jiki zai yi tasiri sosai akan ƙimar riƙe ruwa na methyl cellulose.Gabaɗaya, mafi girman zafin jiki, mafi munin riƙewar ruwa.Idan yawan zafin jiki na turmi ya wuce 40 ° C, riƙewar ruwa na methyl cellulose zai ragu sosai, yana tasiri sosai ga ginin turmi.
(4) Methyl cellulose yana da tasiri mai mahimmanci akan ginawa da haɗin kai na turmi.“Mannewa” a nan yana nufin ƙarfin haɗin gwiwa da ake ji tsakanin kayan aikin ma’aikaci da katangar bango, wato, juriyar juriyar turmi.Manne yana da girma, juriya na juriya na turmi yana da girma, kuma ƙarfin da ma'aikata ke bukata a cikin aikin da ake amfani da su yana da girma, kuma aikin ginin turmi ba shi da kyau.Haɗin kai na methyl cellulose yana a matsakaicin matakin a cikin samfuran ether cellulose.
2. Hydroxypropyl methyl cellulose (HPMC):
Hydroxypropyl methylcellulose wani nau'in cellulose ne wanda kayan aiki da amfaninsa ke karuwa cikin sauri a cikin 'yan shekarun nan.Yana da ether wanda ba na ionic cellulose ba wanda aka yi daga auduga mai ladabi bayan alkalization, ta amfani da propylene oxide da methyl chloride a matsayin wakili na etherification, ta hanyar jerin halayen.Matsakaicin maye gaba ɗaya shine 1.2 ~ 2.0.Kaddarorinsa sun bambanta dangane da rabon abun ciki na methoxyl zuwa abun ciki na hydroxypropyl.
(1) Hydroxypropyl methylcellulose yana da sauƙin narkewa a cikin ruwan sanyi, kuma zai gamu da matsaloli wajen narkewa cikin ruwan zafi.Amma zafinsa na gelation a cikin ruwan zafi yana da girma fiye da na methyl cellulose.Solubility a cikin ruwan sanyi kuma yana inganta sosai idan aka kwatanta da methyl cellulose.
(2) Dankowar hydroxypropyl methylcellulose yana da alaƙa da nauyin kwayoyin halitta, kuma mafi girman nauyin kwayoyin halitta, mafi girman danko.Hakanan yanayin zafi yana rinjayar danko, yayin da zafin jiki ya karu, danko yana raguwa.Duk da haka, tasirin babban danko da zafinsa ya yi ƙasa da na methyl cellulose.Maganin sa yana da ƙarfi idan an adana shi a cikin zafin jiki.
(3) Riƙewar ruwa na hydroxypropyl methylcellulose ya dogara ne akan ƙarin adadinsa, danko, da dai sauransu, kuma yawan ajiyar ruwa a ƙarƙashin adadin adadin adadin ya fi na methyl cellulose.
(4) Hydroxypropyl methylcellulose yana da kwanciyar hankali ga acid da alkali, kuma maganinsa na ruwa yana da tsayi sosai a cikin kewayon pH = 2 ~ 12.Caustic soda da ruwan lemun tsami suna da ɗan tasiri akan aikin sa, amma alkali na iya hanzarta rushewar kuma ya ɗan ƙara danko.Hydroxypropyl methylcellulose ya tsaya tsayin daka ga gishiri na kowa, amma lokacin da maida hankali na maganin gishiri ya yi girma, dankowar maganin hydroxypropyl methylcellulose yana kula da karuwa.
(5) Hydroxypropyl methylcellulose za a iya haxa shi da ruwa mai narkewa polymer mahadi don samar da uniform da mafi girma danko bayani.Kamar polyvinyl barasa, sitaci ether, kayan lambu danko, da dai sauransu.
(6) Hydroxypropyl methylcellulose yana da mafi kyawun juriya na enzyme fiye da methylcellulose, kuma yiwuwar lalatawar enzymatic na maganin sa yana ƙasa da na methylcellulose.
(7) Mannewar hydroxypropyl methylcellulose zuwa ginin turmi ya fi na methylcellulose girma.
3. Hydroxyethyl cellulose (HEC):
An yi shi daga auduga mai ladabi da aka yi da alkali, kuma an yi shi da ethylene oxide a matsayin wakili na etherification a gaban acetone.Matsayinsa na maye gaba ɗaya shine 1.5 ~ 2.0.Yana da karfi hydrophilicity kuma yana da sauƙin sha danshi.
(1) Hydroxyethyl cellulose yana narkewa a cikin ruwan sanyi, amma yana da wuya a narke cikin ruwan zafi.Maganin sa yana da ƙarfi a babban zafin jiki ba tare da gelling ba.Ana iya amfani da shi na dogon lokaci a ƙarƙashin babban zafin jiki a cikin turmi, amma riƙewar ruwa ya yi ƙasa da na methyl cellulose.
(2) Hydroxyethyl cellulose barga ga janar acid da alkali.Alkaki na iya hanzarta narkarwarsa kuma ya dan kara danko.Rarrabuwar sa a cikin ruwa ya ɗan yi muni fiye da na methyl cellulose da hydroxypropyl methyl cellulose..
(3) Hydroxyethyl cellulose yana da kyakkyawan aikin anti-sag don turmi, amma yana da lokaci mai tsawo don ciminti.
(4) Ayyukan hydroxyethyl cellulose da wasu kamfanoni na cikin gida ke samarwa ya yi ƙasa da na methyl cellulose saboda yawan ruwa da yawan toka.
4. Carboxymethyl cellulose (CMC):
Ionic cellulose ether an yi shi ne daga filaye na halitta (auduga, da dai sauransu) bayan maganin alkali, ta yin amfani da sodium monochloroacetate a matsayin wakili na etherification, da kuma jurewa jerin jiyya.Matsayin musanyawa gabaɗaya shine 0.4 ~ 1.4, kuma aikin sa yana tasiri sosai ta matakin maye gurbin.
(1) Carboxymethyl cellulose ya fi hygroscopic, kuma zai ƙunshi ƙarin ruwa lokacin da aka adana shi a ƙarƙashin yanayi na yau da kullum.
(2) Maganin ruwa na Carboxymethyl cellulose ba zai samar da gel ba, kuma danko zai ragu tare da karuwar zafin jiki.Lokacin da zafin jiki ya wuce 50 ° C, danko ba zai iya jurewa ba.
(3) Kwanciyar PH yana tasiri sosai.Gabaɗaya, ana iya amfani da shi a cikin turmi na tushen gypsum, amma ba a cikin turmi na tushen siminti ba.Lokacin da alkaline sosai, zai rasa danko.
(4) Riƙewar ruwansa yayi ƙasa da na methyl cellulose.Yana da tasiri mai tasiri akan turmi na tushen gypsum kuma yana rage ƙarfinsa.Duk da haka, farashin carboxymethyl cellulose yana da ƙasa sosai fiye da na methyl cellulose.
Lokacin aikawa: Fabrairu-27-2023