Focus on Cellulose ethers

Kakaretso ea Lihlahisoa tsa Hydroxypropyl Methyl Cellulose HPMC

Hydroxypropyl methylcellulose HPMC ke mofuta oa non-ionic cellulose motsoako oa ether. E fapane le ionic methyl carboxymethyl cellulose e tsoakiloeng ether, ha e sebetsane le litšepe tse boima. Ka lebaka la likarohano tse fapaneng tsa dikahare tsa methoxyl le dikahare tsa hydroxypropyl ho hydroxypropyl methylcellulose le viscosities tse fapaneng, ho na le mefuta e mengata e nang le thepa e fapaneng, mohlala, litaba tse phahameng tsa methoxyl le litaba tse tlase tsa hydroxypropyl Ts'ebetso ea eona e haufi le ea methyl cellulose, ha ts'ebetso ea dikahare tse tlase tsa methoxy le dikahare tse phahameng tsa hydroxypropyl li haufi le tsa hydroxypropyl methyl cellulose. Leha ho le joalo, mofuteng o mong le o mong, le hoja ho na le palo e nyenyane feela ea sehlopha sa hydroxypropyl kapa sehlopha se senyenyane sa methoxyl, ho qhibiliha ha metsoako ea lintho tse phelang kapa mocheso oa flocculation ka tharollo ea metsi e fapane haholo.

1. Ho qhibiliha ha hydroxypropyl methylcellulose

①Solubility ea hydroxypropyl methylcellulose ka metsing Hydroxypropyl methylcellulose ha e le hantle ke mofuta oa methylcellulose e fetotsoeng ke propylene oxide (methoxypropylene), kahoo e ntse e na le thepa e tšoanang le ea methyl cellulose Cellulose e na le litšobotsi tse ts'oanang tsa ho qhibiliha ha metsi a batang le ho se qhibilihe ha metsi a chesang. Leha ho le joalo, ka lebaka la sehlopha se fetotsoeng sa hydroxypropyl, mocheso oa eona oa gelation metsing a chesang o phahame haholo ho feta oa methyl cellulose. Mohlala, viscosity ea hydroxypropyl methylcellulose aqueous solution with 2% methoxy content substitution degree DS=0.73 le hydroxypropyl content MS=0.46 ke sehlahisoa sa 500 mpa?s ho 20°C, le mocheso oa gel ea eona E ka fihla haufi le 100° C, athe methyl cellulose mochesong o tšoanang o ka ba 55°C feela. Ha e le ho qhalana ha eona metsing, le eona e ntlafalitsoe haholo. Ka mohlala, pulverized hydroxypropyl methylcellulose (sehlahisoa se nang le boholo ba karolo ea 0.2 ~ 0.5mm le 4% ea viscosity ea 4% ea metsi a 2pa ka 20 ° C e ka rekoa Mocheng oa kamore, e qhibiliha habonolo metsing ntle le ho pholile. .

②Solubility ea hydroxypropyl methylcellulose in organic solvents Ho qhibiliha ha hydroxypropyl methylcellulose ka har'a metsoako ea lintho tse phelang le hona ho molemo ho feta ea methylcellulose. Bakeng sa lihlahisoa tse ka holimo ho 2.1, high-viscosity hydroxypropyl methylcellulose e nang le hydroxypropyl MS = 1.5 ~ 1.8 le methoxy DS=0.2 ~ 1.0, e nang le tekanyo e feletseng ea sebaka se ka holimo ho 1.8, e qhibiliha ka methanol ea anhydrous le ethanol Medium, le metsi a thermoluble. . E boetse e qhibiliha ka har'a hydrocarbons ea chlorine joalo ka methylene chloride le chloroform, le lihlapolli tsa tlhaho tse kang acetone, isopropanol le diacetone joala. Ho qhibiliha ha eona ka har'a metsoako ea tlhaho ho molemo ho feta ho qhibiliha ha metsi.

2. Lintho tse amang viscosity ea hydroxypropyl methylcellulose

Lintlha tse Susumetsang Viscosity ea Hydroxypropyl Methyl Cellulose Boikemisetso bo tloaelehileng ba viscosity ea hydroxypropyl methyl cellulose bo tšoana le ba li-cellulose ethers tse ling. E lekanyetsoa ho 20 ° C ka 2% ea tharollo e nang le metsi e le maemo. Viscosity ea sehlahisoa se tšoanang e eketseha ka ho eketseha ha mahloriso. Bakeng sa lihlahisoa tse nang le litekanyo tse fapaneng tsa limolek'hule sebakeng se le seng, sehlahisoa se nang le boima bo boholo ba limolek'hule se na le viscosity e phahameng. Kamano ea eona le mocheso e tšoana le ea methyl cellulose. Ha mocheso o phahama, viscosity e qala ho fokotseha, empa ha e fihla mocheso o itseng, viscosity e phahama ka tšohanyetso 'me gelation e etsahala. Mocheso oa gel oa lihlahisoa tse tlaase-viscosity o phahame. e phahame. Ntlha ea eona ea gel ha e amane feela le viscosity ea ether, empa hape e amana le karolelano ea motsoako oa sehlopha sa methoxyl le sehlopha sa hydroxypropyl ka ether le boholo ba tekanyo ea kakaretso ea ho fetola. Hoa lokela ho hlokomeloa hore hydroxypropyl methylcellulose le eona ke pseudoplastic, 'me tharollo ea eona e tsitsitse mocheso oa kamore ntle le ho senyeha ha viscosity ntle le monyetla oa ho senyeha ha enzymatic.

3. Hydroxypropyl methylcellulose e hanyetsana le acid le alkali

Hydroxypropyl methylcellulose acid le alkali resistance Hydroxypropyl methylcellulose ka kakaretso e tsitsitse ho li-acids le alkalis, 'me ha e amehe ka mefuta ea pH 2 ~ 12. E ka mamella palo e itseng ea acid e khanyang, Tse kang formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, joalo-joalo Empa acid e concentrated e na le phello ea ho fokotsa viscosity. Li-alkali tse kang caustic soda, potash ea caustic le metsi a lime ha li na phello ho eona, empa li ka eketsa viscosity ea tharollo hanyenyane, ebe li fokotsa butle-butle.

4. The miscibility ea hydroxypropyl methylcellulose

Miscibility ea hydroxypropyl methylcellulose Hydroxypropyl methylcellulose solution e ka kopanngoa le metsoako ea polymer e qhibilihang ka metsing hore e be tharollo e ts'oanang le e hlakileng e nang le viscosity e phahameng. Metsoako ena ea polymer e kenyelletsa polyethylene glycol, polyvinyl acetate, polysilicone, polymethylvinylsiloxane, hydroxyethyl cellulose, le methyl cellulose. Metsoako ea tlhaho e phahameng ea limolek'hule joalo ka gum arabic, tsie bean gum, karaya gum, joalo-joalo le eona e na le tumellano e ntle le tharollo ea eona. Hydroxypropyl methylcellulose e ka boela ea tsoakoa le mannitol ester kapa sorbitol ester ea stearic acid kapa palmitic acid, hape e ka tsoakoa le glycerin, sorbitol le mannitol, 'me metsoako ena e ka sebelisoa e le hydroxypropyl methylcellulose Plasticizer bakeng sa selulose.

5. Insolubilization le solubility ea metsi ea hydroxypropyl methylcellulose

Li-cellulose ethers tse sa qhibilihang ka metsing tsa hydroxypropyl methylcellulose li ka hokahanngoa le aldehyde holim'a metsi, e le hore li-ether tsena tse qhibilihang ka metsing li kenelle ka har'a tharollo 'me li se ke tsa qhibiliha metsing. Li-aldehyde tse etsang hore hydroxypropyl methylcellulose e se ke ea qhibiliha li kenyelletsa formaldehyde, glyoxal, succinic aldehyde, adipaldehyde, joalo-joalo Ha u sebelisa formaldehyde, tlhokomelo e khethehileng e lokela ho lefshoa ho boleng ba pH ba tharollo, eo glyoxal e arabelang ka potlako ka eona, kahoo glyoxal e atisa ho sebelisoa e le crosslink. moemeli tlhahiso ea indasteri. Palo ea mofuta ona oa li-cross-linking agent ka tharollo ke 0.2% ~ 10% ea boima ba ether, haholo-holo 7% ~ 10%, mohlala, 3.3% ~ 6% ea glyoxal ke eona e loketseng ka ho fetisisa. Kakaretso ea mocheso oa phekolo ke 0 ~ 30 ℃, 'me nako ke 1 ~ 120min. Karabelo ea li-cross-linking e lokela ho etsoa tlas'a maemo a acidic. Ka kakaretso, tharollo e qala ka ho eketsoa ka asiti e matla ea inorganic kapa organic carboxylic acid ho lokisa pH ea tharollo ho hoo e ka bang 2 ~ 6, haholo-holo pakeng tsa 4 ~ 6, ebe o eketsa aldehydes ho phethahatsa karabelo e kopanyang. Asiti e sebelisitsoeng e na le hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxyacetic acid, succinic acid kapa citric acid joalo-joalo, moo ka acid ea formic kapa acetic acid e leng bohlale, le formic acid e nepahetse. Asiti le aldehyde le tsona li ka eketsoa ka nako e le 'ngoe ho lumella tharollo hore e be le karabelo e hokahanyang ka har'a mofuta o lakatsehang oa pH. Hangata karabelo ena e sebelisoa ts'ebetsong ea ho qetela ea phekolo nakong ea ho lokisoa ha cellulose ethers. Ka mor'a hore cellulose ether e se ke ea qhibiliha, ho bonolo ho hlatsoa le ho hloekisa ka metsi ka 20 ~ 25 ° C. Ha sehlahisoa se sebelisoa, lintho tsa alkaline li ka kenngoa tharollong ea sehlahisoa ho fetola pH ea tharollo hore e be alkaline, 'me sehlahisoa se tla qhibiliha ka tharollo kapele. Mokhoa ona o boetse o sebetsa ho phekola filimi ka mor'a hore tharollo ea cellulose ether e etsoe filimi ho e etsa filimi e sa tsitsang.

6. Ho hanyetsa ha enzyme ea hydroxypropyl methylcellulose

Khanyetso ea enzyme ea hydroxypropyl methylcellulose ke theoretically cellulose derivatives, joalo ka sehlopha se seng le se seng sa anhydroglucose, haeba ho na le sehlopha se nkang sebaka se tiileng, ha ho bonolo ho tšoaetsoa ke likokoana-hloko, empa ha e le hantle sehlahisoa se felileng Ha boleng ba phapanyetso bo feta 1, e tla boela e fokotsoe ke li-enzyme, e leng se bolelang hore tekanyo ea ho kenya sebaka sa sehlopha ka seng ka ketane ea cellulose ha e tšoane ka ho lekaneng, 'me likokoana-hloko li ka senyeha ho sehlopha se sa nkeng sebaka sa anhydroglucose ho theha tsoekere , e le limatlafatsi bakeng sa likokoana-hloko ho monya. Ka hona, haeba tekanyo ea etherification substitution ea selulose e eketseha, ho hanyetsa khoholeho ea enzymatic ea cellulose ether le eona e tla eketseha. Ho ea ka litlaleho, tlas'a maemo a laoloang, liphello tsa hydrolysis tsa li-enzyme, viscosity e setseng ea hydroxypropyl methylcellulose (DS = 1.9) ke 13.2%, methylcellulose (DS = 1.83) ke 7.3%, methylcellulose (DS = 1.66) ke 3.8%. le selulose ea hydroxyethyl ke 1.7%. Ho ka bonoa hore hydroxypropyl methylcellulose e na le matla a matla a anti-enzyme. Ka hona, khanyetso e ntle ea enzyme ea hydroxypropyl methylcellulose, e kopantsoeng le thepa ea eona e ntle ea dispersibility, thickening le filimi-forming, e sebelisoa ka liphahlo tsa metsi-emulsion, joalo-joalo, 'me ka kakaretso ha ho hlokahale ho eketsa li-preservatives. Leha ho le joalo, bakeng sa polokelo ea nako e telele ea tharollo kapa tšilafalo e ka 'nang ea e-ba teng ka ntle, li-preservatives li ka eketsoa e le tšireletso,' me khetho e ka khethoa ho ea ka litlhoko tsa ho qetela tsa tharollo. Phenylmercuric acetate le manganese fluorosilicate ke li-preservatives tse sebetsang hantle, empa kaofela li na le Chefo, tlhokomelo e tlameha ho lefshoa ts'ebetsong. Ka kakaretso, 1 ~ 5mg ea phenylmercury acetate e ka ekeletsoa ho tharollo ka litha e le nngwe ea tekanyo.

7. Ts'ebetso ea hydroxypropyl methylcellulose membrane

Ts'ebetso ea filimi ea hydroxypropyl methylcellulose Hydroxypropyl methylcellulose e na le thepa e ntle haholo ea ho etsa lifilimi. Tharollo ea eona e nang le metsi kapa motsoako oa motsoako oa tlhaho o koahetsoe holim'a poleiti ea khalase, 'me e fetoha e se nang mebala le e hlakileng ka mor'a ho omisa. Le filimi e thata. E na le khanyetso e ntle ea mongobo 'me e lula e tiile mocheso o phahameng. Haeba hygroscopic plasticizer e eketsoa, ​​bolelele ba eona le ho tenyetseha ha eona ho ka ntlafatsoa. Mabapi le ho ntlafatsa ho feto-fetoha ha maemo, li-plasticizers tse kang glycerin le sorbitol ke tsona tse loketseng ka ho fetisisa. Ka kakaretso, mahloriso a tharollo ke 2% ~ 3%, 'me palo ea plasticizer ke 10% ~ 20% ea cellulose ether. Haeba litaba tsa plasticizer li phahame haholo, ho fokotseha ha colloidal dehydration ho tla etsahala ka mongobo o phahameng. Matla a thata a filimi e kentsoeng ka plasticizer e kholoanyane ho feta ntle le ho eketsa polasetiki, 'me e eketseha ka ho eketseha ha chelete e eketsehileng. Ha e le hygroscopicity ea filimi, e boetse e eketseha ka keketseho ea palo ea plasticizer.


Nako ea poso: Apr-01-2023
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