Hydroxypropyl methylcellulose HPMC yog ib hom non-ionic cellulose tov ether. Sib txawv ntawm ionic methyl carboxymethyl cellulose sib xyaw ether, nws tsis hnov mob nrog cov hlau hnyav. Vim muaj qhov sib txawv ntawm cov ntsiab lus methoxyl thiab hydroxypropyl cov ntsiab lus hauv hydroxypropyl methylcellulose thiab cov viscosities sib txawv, muaj ntau ntau yam nrog cov khoom sib txawv, piv txwv li, cov ntsiab lus methoxyl siab thiab cov ntsiab lus tsis tshua muaj hydroxypropyl Nws qhov kev ua tau zoo yog ze rau ntawm methyl cellulose, thaum ua haujlwm ntawm Cov ntsiab lus methoxy qis thiab cov ntsiab lus siab hydroxypropyl yog ze rau ntawm hydroxypropyl methyl cellulose. Txawm li cas los xij, nyob rau hauv txhua yam, txawm hais tias tsuas yog ib qho me me ntawm pawg hydroxypropyl lossis ib qho me me ntawm pawg methoxyl muaj, qhov solubility hauv cov kuab tshuaj organic lossis qhov kub ntawm flocculation hauv cov kua dej sib txawv heev.
1. Lub solubility ntawm hydroxypropyl methylcellulose
① Solubility ntawm hydroxypropyl methylcellulose hauv dej Hydroxypropyl methylcellulose yog ib hom methylcellulose hloov los ntawm propylene oxide (methoxypropylene), yog li nws tseem muaj cov khoom zoo ib yam li methyl cellulose Cellulose muaj cov yam ntxwv zoo sib xws ntawm cov dej txias solubility thiab dej kub insolubility. Txawm li cas los xij, vim yog hloov kho hydroxypropyl pawg, nws qhov kub thiab txias hauv dej kub yog siab dua li ntawm methyl cellulose. Piv txwv li, viscosity ntawm hydroxypropyl methylcellulose aqueous tov nrog 2% methoxy cov ntsiab lus hloov pauv degree DS = 0.73 thiab hydroxypropyl cov ntsiab lus MS = 0.46 yog cov khoom ntawm 500 mpa?s ntawm 20 ° C, thiab nws cov gel kub Nws tuaj yeem ncav cuag ze li 100 °. C, thaum methyl cellulose ntawm tib qhov kub tsuas yog li 55 ° C. Raws li rau nws cov kev sib cais hauv dej, nws kuj tau zoo heev. Piv txwv li, pulverized hydroxypropyl methylcellulose (ib yam khoom uas muaj qhov loj me ntawm 0.2 ~ 0.5mm thiab 4% aqueous tov viscosity ntawm 2pa?s ntawm 20 ° C tuaj yeem muas ntawm chav tsev kub, nws yooj yim soluble hauv dej tsis txias. .
② Solubility ntawm hydroxypropyl methylcellulose hauv cov kuab tshuaj organic Lub solubility ntawm hydroxypropyl methylcellulose hauv cov kuab tshuaj organic kuj zoo dua li ntawm methylcellulose. Rau cov khoom siab tshaj 2.1,High-viscosity hydroxypropyl methylcellulosemuaj hydroxypropyl MS = 1.5 ~ 1.8 thiab methoxy DS = 0.2 ~ 1.0, nrog rau tag nrho cov kev hloov pauv saum toj no 1.8, yog soluble hauv anhydrous methanol thiab ethanol daws nruab nrab, thiab thermoplastic thiab dej-soluble. Nws kuj yog soluble hauv chlorinated hydrocarbons xws li methylene chloride thiab chloroform, thiab cov organic solvents xws li acetone, isopropanol thiab diacetone cawv. Nws solubility hauv cov kuab tshuaj organic zoo dua li dej solubility.
2. Cov yam ntxwv cuam tshuam rau viscosity ntawm hydroxypropyl methylcellulose
Cov yam ntxwv cuam tshuam rau viscosity ntawm Hydroxypropyl Methyl Cellulose Tus qauv viscosity kev txiav txim siab ntawm hydroxypropyl methyl cellulose yog tib yam li lwm cov cellulose ethers. Nws yog ntsuas ntawm 20 ° C nrog 2% aqueous tov raws li tus qauv. Lub viscosity ntawm tib cov khoom nce nrog qhov nce ntawm cov concentration. Rau cov khoom uas muaj qhov sib txawv molecular hnyav ntawm tib qhov concentration, cov khoom uas muaj qhov hnyav dua molecular muaj viscosity ntau dua. Nws txoj kev sib raug zoo nrog kub yog zoo ib yam li cov methyl cellulose. Thaum kub nce, viscosity pib txo, tab sis thaum nws nce mus txog qhov kub thiab txias, qhov viscosity dheev nce thiab gelation tshwm sim. Lub gel kub ntawm cov khoom uas tsis muaj viscosity yog siab dua. yog siab. Nws cov ntsiab lus gel tsis yog tsuas yog cuam tshuam nrog viscosity ntawm ether, tab sis kuj muaj feem xyuam rau qhov sib piv ntawm methoxyl pawg thiab hydroxypropyl pawg hauv ether thiab qhov loj ntawm tag nrho cov kev hloov pauv. Nws yuav tsum tau muab sau tseg tias hydroxypropyl methylcellulose kuj yog pseudoplastic, thiab nws cov tshuaj yog ruaj khov nyob rau hauv chav tsev kub yam tsis muaj degradation nyob rau hauv viscosity tsuas yog muaj peev xwm ntawm enzymatic degradation.
3. Hydroxypropyl methylcellulose tiv taus cov kua qaub thiab alkali
Hydroxypropyl methylcellulose acid thiab alkali tsis kam Hydroxypropyl methylcellulose feem ntau ruaj khov rau cov kua qaub thiab alkalis, thiab tsis cuam tshuam rau thaj tsam ntawm pH 2 ~ 12. Nws tuaj yeem tiv taus qee yam ntawm lub teeb acid, xws li formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, thiab lwm yam. Tab sis concentrated acid muaj cov nyhuv ntawm kev txo viscosity. Alkalis xws li caustic soda, caustic potash thiab txiv qaub dej tsis muaj kev cuam tshuam rau nws, tab sis lawv tuaj yeem ua rau me ntsis viscosity ntawm cov tshuaj, thiab maj mam txo nws.
4. Lub miscibility ntawm hydroxypropyl methylcellulose
Miscibility ntawm hydroxypropyl methylcellulose Hydroxypropyl methylcellulose tov tuaj yeem tov nrog dej-soluble polymer tebchaw los ua ib qho kev sib xws thiab pob tshab nrog cov viscosity siab dua. Cov khoom siv polymer no suav nrog polyethylene glycol, polyvinyl acetate, polysilicone, polymethylvinylsiloxane, hydroxyethyl cellulose, thiab methyl cellulose. Ntuj siab molecular tebchaw xws li cov pos hniav arabic, locust taum gum, karaya gum, thiab lwm yam kuj muaj zoo compatibility nrog nws cov tshuaj. Hydroxypropyl methylcellulose kuj tuaj yeem tov nrog mannitol ester lossis sorbitol ester ntawm stearic acid lossis palmitic acid, thiab tseem tuaj yeem tov nrog glycerin, sorbitol thiab mannitol, thiab cov tshuaj no tuaj yeem siv los ua hydroxypropyl methylcellulose Plasticizer rau cellulose.
5. Insolubilization thiab dej solubility ntawm hydroxypropyl methylcellulose
Cov dej-soluble cellulose ethers ntawm hydroxypropyl methylcellulose tuaj yeem txuas nrog aldehydes ntawm qhov chaw, kom cov dej-soluble ethers no precipitated hauv cov tshuaj thiab ua insoluble hauv dej. Cov aldehydes uas ua rau hydroxypropyl methylcellulose insoluble muaj xws li formaldehyde, glyoxal, succinic aldehyde, adipaldehyde, thiab lwm yam. Thaum siv formaldehyde, tshwj xeeb yuav tsum tau them rau tus nqi pH ntawm cov tshuaj, ntawm cov glyoxal reacts sai, yog li glyoxal feem ntau siv raws li ib tug crosslinking. tus neeg sawv cev hauv industrial ntau lawm. Tus nqi ntawm qhov sib txuas ntawm tus neeg sawv cev hauv cov tshuaj no yog 0.2% ~ 10% ntawm qhov loj ntawm ether, nyiam dua 7% ~ 10%, piv txwv li, 3.3% ~ 6% ntawm glyoxal yog qhov tsim nyog tshaj. Qhov kev kho mob dav dav yog 0 ~ 30 ℃, thiab lub sijhawm yog 1 ~ 120min. Cov tshuaj tiv thaiv kev sib txuas yuav tsum tau ua nyob rau hauv acidic tej yam kev mob. Feem ntau, cov tshuaj yog thawj zaug ntxiv nrog inorganic muaj zog acid lossis organic carboxylic acid los kho cov pH ntawm cov tshuaj mus txog 2 ~ 6, nyiam dua ntawm 4 ~ 6, thiab tom qab ntawd ntxiv aldehydes los ua cov tshuaj tiv thaiv kev sib txuas. Cov kua qaub uas siv tau muaj hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxyacetic acid, succinic acid los yog citric acid thiab lwm yam, nyob rau hauv uas nrog formic acid los yog acetic acid yog advisable, thiab formic acid yog pom zoo. Cov kua qaub thiab aldehyde kuj tseem tuaj yeem ntxiv ib txhij kom tso cai rau kev daws kom muaj kev sib txuas sib txuas hauv qhov xav tau pH ntau. Cov tshuaj tiv thaiv no feem ntau yog siv rau hauv cov txheej txheem kho zaum kawg hauv kev npaj ntawm cellulose ethers. Tom qab cov cellulose ether yog insoluble, nws yog yooj yim los ntxuav thiab ntxuav nrog dej ntawm 20 ~ 25 ° C. Thaum cov khoom siv, cov tshuaj alkaline tuaj yeem muab ntxiv rau hauv cov tshuaj ntawm cov khoom los kho cov pH ntawm cov tshuaj kom alkaline, thiab cov khoom yuav yaj hauv cov tshuaj sai sai. Txoj kev no kuj tseem siv tau rau kev kho cov yeeb yaj kiab tom qab cov tshuaj cellulose ether tau ua rau hauv cov yeeb yaj kiab kom nws ua ib zaj duab xis insoluble.
6. Enzyme tsis kam ntawm hydroxypropyl methylcellulose
Lub enzyme tsis kam ntawm hydroxypropyl methylcellulose yog theoretically cellulose derivatives, xws li txhua pawg anhydroglucose, yog tias muaj ib pab pawg neeg sib koom ua ke, nws tsis yooj yim rau kev kis kab mob los ntawm cov kab mob, tab sis qhov tseeb cov khoom tiav thaum hloov pauv tus nqi ntau dua 1, nws Nws kuj tseem yuav degraded los ntawm enzymes, uas txhais tau hais tias qhov degree ntawm kev hloov ntawm txhua pab pawg ntawm cov cellulose saw tsis zoo txaus, thiab microorganisms yuav erode ntawm unsubstituted anhydroglucose pab pawg neeg los tsim cov suab thaj, raws li zoo raws li cov as-ham rau microorganisms nqus. Yog li, yog tias qib ntawm etherification hloov pauv ntawm cellulose nce, qhov kev tiv thaiv rau enzymatic yaig ntawm cellulose ether kuj yuav nce. Raws li cov lus ceeb toom, nyob rau hauv kev tswj hwm, cov txiaj ntsig ntawm hydrolysis ntawm cov enzymes, qhov seem viscosity ntawm hydroxypropyl methylcellulose (DS = 1.9) yog 13.2%, methylcellulose (DS = 1.83) yog 7.3%, methylcellulose (DS = 1.66) yog 3.8%, thiab hydroxyethyl cellulose yog 1.7%. Nws tuaj yeem pom tias hydroxypropyl methylcellulose muaj peev xwm tiv thaiv enzyme. Yog li ntawd, qhov zoo heev enzyme kuj ntawm hydroxypropyl methylcellulose, ua ke nrog nws zoo dispersibility, thickening thiab film-forming zog, yog siv nyob rau hauv dej-emulsion txheej, thiab lwm yam, thiab feem ntau tsis tas yuav ntxiv preservatives. Txawm li cas los xij, rau kev khaws cia ntev ntev ntawm kev daws teeb meem lossis tuaj yeem kis tau los ntawm sab nraud, cov tshuaj tua kab mob tuaj yeem raug ntxiv raws li kev ceev faj, thiab kev xaiv tuaj yeem txiav txim siab raws li qhov xav tau kawg ntawm kev daws. Phenylmercuric acetate thiab manganese fluorosilicate yog cov tshuaj tiv thaiv zoo, tab sis lawv txhua tus muaj Toxicity, yuav tsum tau them nyiaj rau kev ua haujlwm. Feem ntau, 1 ~ 5mg ntawm phenylmercury acetate tuaj yeem muab ntxiv rau cov tshuaj ib liter ntawm cov tshuaj.
7. Kev ua tau zoo ntawm hydroxypropyl methylcellulose membrane
Kev ua haujlwm ntawm hydroxypropyl methylcellulose zaj duab xis Hydroxypropyl methylcellulose muaj cov yeeb yaj kiab zoo heev. Nws cov tshuaj aqueous los yog cov kuab tshuaj organic yog coated rau ntawm iav phaj, thiab nws yuav tsis muaj xim thiab pob tshab tom qab ziab. Thiab tawv tawv. Nws muaj cov dej noo zoo thiab tseem nyob ruaj khov ntawm qhov kub thiab txias. Yog hais tias hygroscopic plasticizer ntxiv, nws elongation thiab yooj tuaj yeem txhim kho. Nyob rau hauv cov nqe lus ntawm kev txhim kho yooj, plasticizers xws li glycerin thiab sorbitol yog qhov tsim nyog tshaj plaws. Feem ntau, cov tshuaj concentration yog 2% ~ 3%, thiab cov yas yas yog 10% ~ 20% ntawm cellulose ether. Yog tias cov ntsiab lus ntawm plasticizer siab dhau lawm, colloidal dehydration shrinkage yuav tshwm sim ntawm cov av noo siab. Lub zog tensile ntawm zaj duab xis ntxiv nrog plasticizer yog loj dua li qhov tsis muaj qhov sib ntxiv, thiab nce nrog qhov nce ntawm cov nyiaj ntxiv, thiab hygroscopicity ntawm cov yeeb yaj kiab kuj nce ntxiv nrog qhov nce ntawm cov nyiaj ntawm plasticizer.
Post lub sij hawm: Dec-19-2022