Hydroxypropyl methylcelluloseyog ib hom non-ionic cellulose sib xyaw ether. Tsis zoo li ionic methyl carboxymethyl cellulose sib xyaw ether, nws tsis cuam tshuam nrog cov hlau hnyav. Vim yog qhov sib txawv ntawm methoxyl cov ntsiab lus thiab hydroxypropyl cov ntsiab lus hauv hydroxypropyl methylcellulose thiab viscosities sib txawv, muaj ntau yam nrog cov khoom sib txawv, piv txwv li, cov ntsiab lus methoxyl siab thiab cov ntsiab lus hydroxypropyl qis Nws cov kev ua tau zoo yog ze rau qhov ntawm methyl cellulose, thaum qhov kev ua tau zoo ntawm cov ntsiab lus methoxyl qis thiab cov ntsiab lus hydroxypropyl siab yog ze rau qhov ntawm hydroxypropyl methyl cellulose. Txawm li cas los xij, hauv txhua hom, txawm hais tias tsuas yog me me ntawm hydroxypropyl pawg lossis me me ntawm methoxyl pawg muaj, muaj qhov sib txawv loj hauv solubility hauv cov organic solvents lossis qhov kub flocculation hauv cov kua dej.
(1) Cov khoom yaj ntawm hydroxypropyl methylcellulose
① Kev yaj ntawm hydroxypropyl methylcellulose hauv dejHydroxypropyl methylcelluloseQhov tseeb, nws yog ib hom methylcellulose uas tau hloov kho los ntawm propylene oxide (methoxy-propylene), yog li nws tseem muaj cov khoom zoo ib yam li methyl cellulose. Nws muaj cov yam ntxwv zoo sib xws ntawm kev yaj hauv dej txias thiab kev yaj hauv dej kub. Txawm li cas los xij, vim yog pawg hydroxypropyl hloov kho, nws qhov kub gelation hauv dej kub siab dua li ntawm methyl cellulose. Piv txwv li, qhov viscosity ntawm hydroxypropyl methylcellulose aqueous solution nrog 2% methoxy cov ntsiab lus hloov chaw degree DS = 0.73 thiab hydroxypropyl cov ntsiab lus MS = 0.46 yog 500 mpa · s ntawm 20 ° C, thiab nws qhov kub gel Nws tuaj yeem ncav cuag ze li ntawm 100 ° C, thaum methyl cellulose ntawm tib qhov kub tsuas yog li 55 ° C. Raws li nws cov solubility hauv dej, nws kuj tau txhim kho zoo heev. Piv txwv li, cov hydroxypropyl methylcellulose uas raug pulverized (cov duab granular 0.2 ~ 0.5 hli ntawm 20 ° C nrog 4% aqueous solution viscosity ntawm 2 pa • s tuaj yeem yuav tau ntawm chav tsev kub, nws yooj yim soluble hauv dej yam tsis tau txias.
② Kev yaj ntawm hydroxypropyl methylcellulose hauv cov kuab tshuaj organic, kev yaj ntawm hydroxypropyl methylcellulose hauv cov kuab tshuaj organic kuj zoo dua li ntawm methylcellulose. Methylcellulose yuav tsum muaj qib hloov methoxyl ntawm 2.1 Cov khoom saum toj no, tab sis muaj hydroxypropyl MS = 1.5 ~ 1.8 thiab methoxy DS = 0.2 ~ 1.0, cov hydroxypropyl methylcellulose uas muaj viscosity siab nrog tag nrho qib hloov siab tshaj 1.8 yog yaj hauv anhydrous methanol thiab ethanol daws, thiab muaj thermos-plasticity thiab dej solubility. Nws kuj yaj hauv chlorinated hydrocarbons xws li methylene chloride thiab chloroform, thiab cov kuab tshuaj organic xws li acetone, isopropanol thiab diacetone cawv. Nws solubility hauv cov kuab tshuaj organic zoo dua li dej solubility.
(2) Yam Uas Cuam Tshuam Rau Qhov Viscosity Ntawm Hydroxypropyl Methyl Cellulose Kev txiav txim siab txog qhov viscosity ntawm hydroxypropyl methyl cellulose zoo ib yam li lwm cov cellulose ethers. Nws ntsuas ntawm 20 ° C nrog 2% aqueous kua ua tus qauv. Qhov viscosity ntawm tib yam khoom nce nrog qhov nce ntawm concentration. Rau cov khoom uas muaj qhov hnyav molecular sib txawv ntawm tib qhov concentration, cov khoom uas muaj qhov hnyav molecular loj dua muaj viscosity siab dua. Nws txoj kev sib raug zoo nrog qhov kub thiab txias zoo ib yam li methyl cellulose. Thaum qhov kub nce, qhov viscosity pib poob, tab sis thaum nws mus txog qee qhov kub, qhov viscosity nce siab thiab gelation tshwm sim. Qhov kub gel ntawm cov khoom viscosity qis dua. yog siab. Nws cov gel point tsis yog tsuas yog cuam tshuam nrog viscosity ntawm ether, tab sis kuj cuam tshuam nrog qhov sib piv ntawm methoxyl pawg thiab hydroxypropyl pawg hauv ether thiab qhov loj ntawm tag nrho cov degree hloov chaw. Nws yuav tsum tau sau tseg tias hydroxypropyl methylcellulose kuj yog pseudoplastic, thiab nws cov tshuaj ruaj khov ntawm chav tsev kub yam tsis muaj kev puas tsuaj ntawm viscosity tsuas yog qhov ua tau ntawm enzymatic degradation.
(3) Kev kam rau ntsev ntawm hydroxypropyl methylcellulose Vim tias hydroxypropyl methylcellulose yog cov ether tsis-ionic, nws tsis yog ionized hauv dej media, tsis zoo li lwm cov ionic cellulose ethers, xws li carboxymethyl Base cellulose, hauv cov tshuaj kom cuam tshuam nrog cov hlau hnyav ions thiab precipitate. Cov ntsev dav dav xws li chloride, bromide, phosphate, nitrate, thiab lwm yam yuav tsis precipitate thaum ntxiv rau nws cov kua aqueous. Txawm li cas los xij, qhov ntxiv ntsev muaj qee qhov cuam tshuam rau qhov kub flocculation ntawm nws cov kua aqueous. Thaum cov ntsev concentration nce, qhov kub gel txo qis. Thaum cov ntsev concentration qis dua qhov flocculation point, qhov viscosity ntawm cov tshuaj feem ntau nce. Yog li ntawd, ib qho nyiaj ntawm ntsev ntxiv, hauv daim ntawv thov, nws tuaj yeem ua tiav cov nyhuv thickening ntau dua. Yog li ntawd, hauv qee qhov kev siv, nws zoo dua los siv cov sib xyaw ntawm cellulose ether thiab ntsev dua li qhov concentration siab dua ntawm ether kua kom ua tiav cov nyhuv thickening.
(4) Hydroxypropyl methylcellulose acid thiab alkali tsis kam Hydroxypropyl methylcellulose feem ntau ruaj khov rau cov kua qaub thiab alkalis, thiab tsis cuam tshuam rau hauv qhov ntau ntawm pH 2 ~ 12. Nws tuaj yeem tiv taus qee qhov ntawm cov kua qaub teeb, Xws li formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, thiab lwm yam. Tab sis cov kua qaub concentrated muaj cov nyhuv ntawm kev txo cov viscosity. Cov alkalis xws li caustic soda, caustic potash thiab cov dej txiv qaub tsis muaj cov nyhuv rau nws, tab sis lawv tuaj yeem ua rau me ntsis nce qhov viscosity ntawm cov tshuaj, thiab tom qab ntawd maj mam txo nws.
(5) Kev sib xyaw ua ke ntawm hydroxypropyl methylcellulose Hydroxypropyl methylcellulose kua tuaj yeem sib xyaw nrog cov tshuaj polymer uas yaj tau hauv dej kom ua ib qho kev daws teeb meem sib xws thiab pob tshab nrog viscosity siab dua. Cov tshuaj polymer no suav nrog polyethylene glycol, polyvinyl acetate, polysilicone, polymethylvinyl siloxane, hydroxyethyl cellulose, thiab methyl cellulose. Cov tshuaj molecular siab ntuj xws li gum arabic, locust bean gum, karaya gum, thiab lwm yam kuj muaj kev sib raug zoo nrog nws cov kua. Hydroxypropyl methylcellulose kuj tuaj yeem sib xyaw nrog mannitol ester lossis sorbitol ester ntawm stearic acid lossis palmitic acid, thiab kuj tuaj yeem sib xyaw nrog glycerin, sorbitol thiab mannitol, thiab cov tshuaj no tuaj yeem siv ua hydroxypropyl methylcellulose Plasticizer rau cellulose.
(6) Cov dej uas tsis yaj taucov cellulose ethersntawm hydroxypropyl methylcellulose tuaj yeem nqa tawm ntawm qhov chaw hla-linking nrog aldehydes, yog li cov dej-soluble ethers no precipitated nyob rau hauv cov tshuaj thiab ua insoluble nyob rau hauv dej. Cov aldehydes uas ua rau hydroxypropyl methylcellulose insoluble suav nrog formaldehyde, glyoxal, succinic aldehyde, adipaldehyde, thiab lwm yam. Thaum siv formaldehyde, tshwj xeeb mloog yuav tsum tau them rau tus nqi pH ntawm cov tshuaj, ntawm cov uas glyoxal reacts sai dua, yog li glyoxal feem ntau yog siv ua tus neeg sawv cev crosslinking hauv kev tsim khoom lag luam. Cov koob tshuaj ntawm hom cross-linking tus neeg sawv cev no hauv cov tshuaj 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 plaws. Feem ntau, qhov kub kho mob yog 0 ~ 30 ℃, thiab lub sijhawm yog 1 ~ 120 feeb. Qhov kev sib txuas lus crosslinking yuav tsum tau ua nyob rau hauv cov xwm txheej acidic. Feem ntau, pH ntawm cov tshuaj raug kho kom txog li 2 ~ 6 los ntawm kev ntxiv cov inorganic strong acid lossis organic carboxylic acid rau hauv cov tshuaj, zoo dua ntawm 4 ~ 6, thiab tom qab ntawd aldehydes raug ntxiv los ua qhov kev sib txuas. Cov kua qaub siv muaj hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxy-acetic acid, succinic acid lossis citric acid thiab lwm yam, qhov twg nrog formic acid lossis acetic acid yog qhov zoo tshaj plaws, thiab formic acid yog qhov zoo tshaj plaws. Cov kua qaub thiab aldehyde kuj tseem tuaj yeem ntxiv tib lub sijhawm kom tso cai rau cov tshuaj kom dhau los ua qhov kev sib txuas hauv pH xav tau. Cov tshuaj tiv thaiv no feem ntau siv rau hauv cov txheej txheem kho zaum kawg hauv cov txheej txheem npaj ntawm cellulose ethers. Tom qab cellulose ether tsis yaj, nws yooj yim siv.
20 ~ 25 ℃ dej rau ntxuav thiab ntxuav. Thaum cov khoom siv, cov tshuaj alkaline tuaj yeem ntxiv rau hauv cov tshuaj ntawm cov khoom kom kho qhov pH ntawm cov tshuaj kom ua alkaline, thiab cov khoom yuav yaj sai sai hauv cov tshuaj. Txoj kev no kuj siv tau rau kev kho cov zaj duab xis tom qab cov tshuaj cellulose ether ua rau hauv zaj duab xis kom ua rau nws ua zaj duab xis tsis yaj.
(7) Qhov kev tiv thaiv enzyme ntawm hydroxypropyl methylcellulose yog theoretically cellulose derivatives, xws li txhua pawg anhydroglucose, yog tias muaj ib pawg substituent sib txuas ruaj khov, nws tsis yooj yim rau kev kis tus kab mob los ntawm cov kab mob me me, tab sis qhov tseeb cov khoom tiav Thaum tus nqi hloov pauv tshaj 1, nws kuj tseem yuav raug rhuav tshem los ntawm cov enzymes, uas txhais tau tias qib ntawm kev hloov pauv ntawm txhua pawg ntawm cov saw cellulose tsis sib xws txaus, thiab cov kab mob me me tuaj yeem tawg ntawm pawg anhydroglucose tsis hloov pauv los ua cov suab thaj, ua cov as-ham rau cov kab mob me me kom nqus tau. Yog li ntawd, yog tias qib ntawm etherification hloov pauv ntawm cellulose nce ntxiv, qhov kev tiv thaiv rau enzymatic erosion ntawm cellulose ether kuj tseem yuav nce ntxiv. Raws li cov ntawv ceeb toom, nyob rau hauv cov xwm txheej tswj hwm, cov txiaj ntsig hydrolysis ntawm cov enzymes ua, 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 muaj zog. Yog li ntawd, qhov kev tiv thaiv enzyme zoo heev ntawm hydroxypropyl methylcellulose, ua ke nrog nws cov khoom dispersibility zoo, thickening thiab zaj duab xis-tsim cov khoom, yog siv rau hauv dej-emulsion coatings, thiab lwm yam, thiab feem ntau tsis tas yuav ntxiv preservatives. Txawm li cas los xij, rau lub sijhawm ntev khaws cia ntawm cov tshuaj lossis ua tau los ntawm sab nraud, preservatives tuaj yeem ntxiv ua kev ceev faj, thiab kev xaiv tuaj yeem txiav txim siab raws li qhov kawg xav tau ntawm cov tshuaj. Phenylmercuric acetate thiab manganese fluorosilicate yog cov preservatives zoo, tab sis lawv txhua tus muaj Toxicity, yuav tsum tau them sai sai rau kev ua haujlwm. Feem ntau, 1 ~ 5mg ntawm phenylmercury acetate tuaj yeem ntxiv rau hauv cov tshuaj rau ib liter ntawm cov tshuaj.
(8) Kev ua tau zoo ntawmhydroxypropyl methylcelluloseZaj duab xis Hydroxypropyl methylcellulose muaj cov khoom zoo heev rau kev tsim zaj duab xis. Nws cov kua dej lossis cov kua organic solvent yog coated rau ntawm lub phaj iav, thiab nws ua tsis muaj xim thiab pob tshab tom qab ziab. Thiab zaj duab xis tawv. Nws muaj kev tiv thaiv dej noo zoo thiab tseem khov kho ntawm qhov kub siab. Yog tias ntxiv hygroscopic plasticizer, nws elongation thiab elasticity tuaj yeem txhim kho. Hauv cov nqe lus ntawm kev txhim kho kev ywj pheej, cov plasticizers xws li glycerin thiab sorbitol yog qhov tsim nyog tshaj plaws. Feem ntau, qhov concentration ntawm cov tshuaj yog 2% ~ 3%, thiab qhov ntau ntawm plasticizer yog 10% ~ 20% ntawm cellulose ether. Yog tias cov ntsiab lus ntawm plasticizer siab dhau, colloidal dehydration shrinkage yuav tshwm sim ntawm qhov av noo siab. Lub zog tensile ntawm zaj duab xis nrog plasticizer ntxiv yog loj dua li tsis muaj plasticizer, thiab nws nce nrog qhov nce ntawm qhov ntxiv. Raws li rau hygroscopicity ntawm zaj duab xis, nws kuj nce nrog qhov nce ntawm qhov ntau ntawm plasticizer.
Lub sijhawm tshaj tawm: Plaub Hlis-25-2024