Focus on Cellulose ethers

Bambanci tsakanin HPMC da MC, HEC, CMC

Cellulose yafi taka rawa uku na kauri, riƙe ruwa da gini a turmi da fenti.

Kauri: Za a iya kauri cellulose don dakatarwa da kuma kiyaye maganin daidai sama da ƙasa, da tsayayya da sagging.

Riƙewar ruwa: sanya turmi da fenti ya bushe a hankali, kuma suna taimakawa kayan kamar toka da alli don amsawa ƙarƙashin aikin ruwa.

Gina: Cellulose yana da tasirin mai, wanda zai iya yin turmi da sutura suna da kyawawan kayan gini.

1. Methyl cellulose (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 adadin 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 aikin aiki da adhesion na turmi.“Maɗaukaki” a nan yana nufin ƙarfin mannewa 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.Methyl cellulose adhesion yana a matsakaicin matakin a cikin samfuran ether cellulose.

2. Hydroxypropylmethylcellulose (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 saboda bambancin rabo na abun ciki na methoxyl da 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) Dankin 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, babban danko yana da tasirin zafi fiye da 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 ya tsaya tsayin daka ga acid da alkali, kuma maganinsa mai ruwa ya tsaya 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 yana 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.Adhesion na hydroxypropyl methylcellulose zuwa turmi gini 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.Matsakaicin 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 an bi da shi tare da alkali kuma an yi amfani da shi azaman wakili na etherification ta hanyar jiyya na amsawa.Matsakaicin maye gaba ɗaya 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 baya samar da gel, kuma danko yana raguwa tare da karuwar zafin jiki.Lokacin da zafin jiki ya wuce 50 ° C, danko ba zai iya jurewa ba.

(3) kwanciyar hankali yana tasiri sosai ta pH.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, yana 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

Matsayin hydroxypropyl methylcellulose a cikin masana'antar sutura: Saboda HPMC yana da kaddarorin kama da sauran ethers masu narkewa na ruwa, ana iya amfani da shi azaman wakili na fim, thickener, emulsifier da stabilizer a cikin fenti na emulsion da abubuwan fenti mai narkewa mai narkewa.wakili, da dai sauransu, don haka rufin yana da juriya mai kyau.Leveling da adhesion, da ingantacciyar tashin hankali na sama, kwanciyar hankali ga acid da alkali, da dacewa da launuka na ƙarfe.Saboda ma'aunin gel na HPMC ya fi na MC, juriya ga yashwar kwayan cuta shima ya fi sauran ethers cellulose ƙarfi, don haka ana iya amfani da shi azaman mai kauri don fenti na ruwa-emulsion.HPMC yana da kyau danko ajiya kwanciyar hankali, kuma yana da kyau kwarai dispersibility, don haka shi ne musamman dace a matsayin dispersant a emulsified coatings.


Lokacin aikawa: Maris-04-2023
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