Hydroxypropylmethylcellulose

Txheej txheem cej luam: hu ua HPMC, dawb los yog tawm-dawb fibrous los yog granular hmoov. Muaj ntau ntau hom cellulose thiab tau siv dav, tab sis peb tsuas yog tiv tauj nrog cov neeg siv khoom hauv kev lag luam cov khoom siv hmoov qhuav qhuav. Feem ntau cov cellulose yog hais txog hypromellose.

Cov txheej txheem ntau lawm: Cov ntaub ntawv tseem ceeb ntawm HPMC: refined paj rwb, methyl chloride, propylene oxide, lwm yam raw cov ntaub ntawv xws li flake alkali, acid, toluene, isopropanol, thiab lwm yam. Kho cov refined paj rwb cellulose nrog alkali tov ntawm 35-40 ℃ rau ib nrab ib teev, nias, pulverize cellulose 35 lub hnub nyoog ntawm cov polymerization ntawm lub hnub nyoog li ntawd. yog nyob rau hauv qhov yuav tsum tau muaj. Muab cov alkali fibers tso rau hauv etherification kettle, ntxiv propylene oxide thiab methyl chloride nyob rau hauv lem, thiab etherify ntawm 50-80 ° C rau 5 teev, nrog rau siab tshaj plaws ntawm txog 1.8 MPa. Tom qab ntawd ntxiv qhov tsim nyog ntawm hydrochloric acid thiab oxalic acid rau hauv dej kub ntawm 90 ° C los ntxuav cov khoom kom nthuav dav. Dehydrate nrog lub centrifuge. Ntxuav kom txog thaum nruab nrab, thiab thaum cov dej noo hauv cov khoom tsawg dua 60%, ziab nws nrog cua kub ntws ntawm 130 ° C mus rau tsawg dua 5%. Muaj nuj nqi: dej tuav, thickening, thixotropic anti-sag, huab cua-entraining workability, retarding chaw.

Kev tuav dej: Kev tuav dej yog qhov tseem ceeb tshaj plaws ntawm cellulose ether! Hauv kev tsim cov gypsum mortar thiab lwm yam ntaub ntawv, daim ntawv thov cellulose ether yog qhov tseem ceeb. Kev tuav dej siab tuaj yeem ua rau cov cement tshauv thiab calcium gypsum tag nrho (qhov ntau dua cov tshuaj tiv thaiv, lub zog ntau dua). Nyob rau tib lub sijhawm, qhov siab dua ntawm cov viscosity ntawm cellulose ether, qhov dej tuav tau zoo dua (qhov sib txawv ntawm 100,000 viscosity yog nqaim); qhov ntau npaum li cas, qhov zoo dua cov dej tuav, feem ntau me me ntawm cellulose ether tuaj yeem txhim kho cov mortar kev ua tau zoo. Tus nqi tuav dej, thaum cov ntsiab lus nce mus txog ib theem, qhov sib txawv ntawm cov dej tuav tau qeeb qeeb; Cov dej tuav tus nqi ntawm cellulose ether feem ntau yuav txo qis thaum lub ambient kub nce, tab sis qee cov high-gel cellulose ethers kuj muaj kev ua tau zoo dua nyob rau hauv qhov kub thiab txias. Kev tuav dej. Kev sib cuam tshuam ntawm cov dej molecules thiab cellulose ether molecular chains ua rau cov dej molecules nkag mus rau sab hauv ntawm cellulose ether macromolecular chains thiab tau txais kev sib khi muaj zog, yog li tsim cov dej dawb, dej entangling, thiab txhim kho cov dej tuav ntawm cov cement slurry.

Thickening, thixotropic thiab anti-sag: imparts zoo heev viscosity rau ntub mortar! Nws tuaj yeem ua rau kom muaj qhov adhesion ntawm cov khib nyiab ntub dej thiab cov txheej txheej, thiab txhim kho cov kev ua haujlwm ntawm cov tshuaj khib nyiab. Cov nyhuv thickening ntawm cellulose ethers kuj nce dispersion kuj thiab homogeneity ntawm cov khoom sib xyaw tshiab, tiv thaiv cov khoom delamination, cais thiab los ntshav. Cov nyhuv thickening ntawm cellulose ethers ntawm cement-based cov ntaub ntawv los ntawm viscosity ntawm cellulose ether daws. Nyob rau tib lub sijhawm, qhov viscosity ntawm cellulose ether ntau dua, qhov viscosity zoo dua ntawm cov khoom siv cement-based, tab sis yog tias cov viscosity loj dhau, nws yuav cuam tshuam rau cov dej ntws thiab kev ua haujlwm ntawm cov khoom siv (xws li nplaum nplaum thiab batch scraper). ua hauj lwm). Self-leveling mortar thiab self-compacting qhob uas yuav tsum tau muaj fluidity yuav tsum tsis muaj viscosity ntawm cellulose ether. Tsis tas li ntawd, cov nyhuv thickening ntawm cellulose ether yuav ua rau kom cov dej xav tau ntawm cov ntaub ntawv cement-based thiab ua kom cov qoob loo ntau ntxiv. High viscosity cellulose ether aqueous tov muaj siab thixotropy, uas kuj yog ib tug tseem ceeb yam ntxwv ntawm cellulose ether. Aqueous kev daws teeb meem ntawm cellulose feem ntau muaj pseudoplastic, uas tsis yog-thixotropic ndlwg zog hauv qab lawv gel kub, tab sis Newtonian ndlwg zog ntawm tsawg shear tus nqi. Pseudoplasticity nce nrog nce molecular hnyav lossis concentration ntawm cellulose ether. Cov txheej txheem gels yog tsim thaum kub nce, thiab siab thixotropic ntws tshwm sim. Cellulose ethers nrog high concentrations thiab tsawg viscosity qhia thixotropy txawm nyob rau hauv lub gel kub. Cov cuab yeej no muaj txiaj ntsig zoo rau kev tsim vaj tsev mortar los kho nws cov qib thiab sag. Nws yuav tsum raug sau tseg ntawm no tias qhov siab dua ntawm cov viscosity ntawm cellulose ether, qhov dej tuav tau zoo dua, tab sis qhov siab dua qhov viscosity, qhov siab dua qhov txheeb ze molecular hnyav ntawm cellulose ether, thiab qhov sib thooj hauv nws cov solubility, uas muaj kev cuam tshuam tsis zoo rau cov mortar concentration thiab workability.

Ua rau: Cellulose ether muaj qhov pom tseeb huab cua nkag mus rau cov khoom siv cement-based tshiab. Cellulose ether muaj ob pawg hydrophilic (piv txwv li hydroxyl, ether pawg) thiab pawg hydrophobic (methyl pab pawg, qabzib lub nplhaib), yog ib qho surfactant, muaj kev ua haujlwm saum npoo av, thiab yog li muaj huab cua nkag mus. Cov huab cua-entraining nyhuv ntawm cellulose ether yuav tsim ib tug "pob" nyhuv, uas yuav txhim khu kev ua hauj lwm ntawm cov khoom sib xyaw tshiab, xws li ua kom cov yas thiab smoothness ntawm lub mortar thaum lub sij hawm ua hauj lwm, uas yog zoo rau cov paving ntawm lub mortar; nws kuj yuav ua rau kom cov zis ntawm mortar. , txo tus nqi ntawm mortar ntau lawm; tab sis nws yuav ua rau kom cov porosity ntawm cov khoom hardened thiab txo nws cov khoom siv xws li lub zog thiab elastic modulus. Raws li ib tug surfactant, cellulose ether kuj muaj ib tug ntub dej los yog lubricating nyhuv ntawm cov cement hais, uas ua ke nrog nws cov huab cua-entraining nyhuv tsub kom lub fluidity ntawm cement-based cov ntaub ntawv, tab sis nws thickening nyhuv yuav txo cov fluidity. Cov nyhuv ntawm ntws yog ib qho kev sib xyaw ntawm plasticizing thiab thickening teebmeem. Thaum cov ntsiab lus ntawm cellulose ether tsawg heev, nws yog tsuas yog manifested li plasticizing los yog dej-txo nyhuv; Thaum cov ntsiab lus siab, cov nyhuv thickening ntawm cellulose ether nce sai, thiab nws cov huab cua-entraining nyhuv nyhav saturated, yog li ntawd qhov kev ua tau zoo yog nce. Thickening nyhuv los yog nce dej thov.

Kev teeb tsa retardation: Cellulose ether tuaj yeem ncua cov txheej txheem dej ntawm cov cement. Cellulose ethers endow lub mortar nrog ntau yam khoom muaj txiaj ntsig, thiab tseem txo qis cov dej kub thaum ntxov ntawm cov cement thiab ncua cov txheej txheem hydration kinetic ntawm cov cement. Qhov no tsis zoo rau kev siv tshuaj khib nyiab hauv thaj chaw txias. Qhov no retardation yog tshwm sim los ntawm adsorption ntawm cellulose ether molecules ntawm hydration khoom xws li CSH thiab ca(OH)2. Vim qhov nce hauv qhov viscosity ntawm cov pore tov, cellulose ether txo qhov kev txav ntawm ions hauv cov tshuaj, yog li ncua cov txheej txheem hydration. Qhov siab dua qhov concentration ntawm cellulose ether nyob rau hauv cov ntxhia gel cov ntaub ntawv, ntau pronounced cov nyhuv ntawm hydration ncua. Cellulose ethers tsis tsuas yog retard qhov chaw, tab sis kuj retard cov txheej txheem hardening ntawm cov cement mortar system. Cov nyhuv retardation ntawm cellulose ether tsis yog nyob ntawm nws cov concentration hauv cov ntxhia gel, tab sis kuj nyob ntawm cov qauv tshuaj. Qhov siab dua qib ntawm methylation ntawm HEMC, qhov zoo dua cov nyhuv retardation ntawm cellulose ether. Cov nyhuv retardation muaj zog dua. Txawm li cas los xij, viscosity ntawm cellulose ether tsis tshua muaj txiaj ntsig rau hydration kinetics ntawm cement. Nrog rau qhov nce ntawm cellulose ether cov ntsiab lus, lub sij hawm teem ntawm mortar nce ho. Muaj kev sib raug zoo tsis zoo nyob nruab nrab ntawm lub sijhawm pib ntawm mortar thiab cov ntsiab lus ntawm cellulose ether, thiab lub sijhawm teem sijhawm kawg muaj kev sib raug zoo nrog cov ntsiab lus ntawm cellulose ether. Peb tuaj yeem tswj lub sijhawm ua haujlwm ntawm cov tshuaj khib los ntawm kev hloov cov ntsiab lus ntawm cellulose ether. Nyob rau hauv cov khoom, nws plays lub luag hauj lwm ntawm dej tuav, thickening, ncua lub cement hydration zog, thiab txhim kho kev tsim kho kev ua tau zoo. Cov dej tuav tau zoo ua rau cov cement gypsum tshauv calcium reacts ntau dua, ua rau kom ntub dej viscosity, txhim kho cov ntawv cog lus lub zog ntawm mortar, thiab tib lub sij hawm tuaj yeem txhim kho tensile lub zog thiab shear lub zog zoo, txhim kho kev tsim kho thiab kev ua haujlwm zoo. Kho lub sij hawm. Txhim kho cov tshuaj tsuag los yog twj tso kua mis ntawm mortar, nrog rau lub zog ntawm cov qauv. Nyob rau hauv txoj kev thov tiag tiag, nws yog ib qho tsim nyog los txiav txim seb hom, viscosity, thiab pes tsawg ntawm cellulose raws li cov khoom sib txawv, kev tsim qauv, thiab ib puag ncig.