Hydroxypropylmethylcellulose

Txheej txheem cej luam: hu ua HPMC, dawb lossis dawb tawm-dawb fibrous lossis granular hmoov. Muaj ntau hom cellulose thiab siv dav, tab sis peb feem ntau tiv tauj nrog cov neeg siv khoom hauv kev lag luam hmoov qhuav tsev. Cov cellulose feem ntau yog hypromellose.

Cov txheej txheem tsim khoom: Cov khoom siv tseem ceeb ntawm HPMC: paj rwb zoo, methyl chloride, propylene oxide, lwm yam khoom siv raw suav nrog flake alkali, acid, toluene, isopropanol, thiab lwm yam. Kho cov paj rwb zoo nrog cov kua alkali ntawm 35-40 ℃ rau ib nrab teev, nias, pulverize cov cellulose, thiab laus kom raug ntawm 35 ℃, yog li qhov nruab nrab ntawm polymerization ntawm cov alkali fiber tau txais yog nyob rau hauv qhov xav tau. Muab cov alkali fibers rau hauv lub lauj kaub etherification, ntxiv propylene oxide thiab methyl chloride ua ke, thiab etherify ntawm 50-80 ° C rau 5 teev, nrog lub siab tshaj plaws ntawm kwv yees li 1.8 MPa. Tom qab ntawd ntxiv cov hydrochloric acid thiab oxalic acid rau hauv dej kub ntawm 90 ° C kom ntxuav cov khoom kom nthuav qhov ntim. 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: khaws dej, ua kom tuab, thixotropic tiv thaiv kev qaug zog, ua haujlwm tau los ntawm huab cua, qeeb qhov chaw.

Kev Khaws Dej: Kev khaws dej yog qhov tseem ceeb tshaj plaws ntawm cellulose ether! Hauv kev tsim cov putty gypsum mortar thiab lwm yam khoom siv, kev siv cellulose ether yog qhov tseem ceeb. Kev khaws dej ntau tuaj yeem ua rau cov tshauv cement thiab calcium gypsum ua haujlwm tau zoo (qhov ua kom tiav ntau npaum li cas, qhov muaj zog ntau dua). Nyob rau hauv tib qho xwm txheej, qhov viscosity ntawm cellulose ether siab dua, qhov khaws dej zoo dua (qhov sib txawv saum toj no 100,000 viscosity yog nqaim); qhov ntau dua ntawm cov koob tshuaj, qhov khaws dej zoo dua, feem ntau me me ntawm cellulose ether tuaj yeem txhim kho qhov kev ua tau zoo ntawm mortar. Tus nqi khaws dej, thaum cov ntsiab lus mus txog qee qib, qhov sib txawv ntawm kev nce tus nqi khaws dej qeeb dua; tus nqi khaws dej ntawm cellulose ether feem ntau txo qis thaum qhov kub thiab txias nce, tab sis qee cov cellulose ethers gel siab kuj muaj kev ua tau zoo dua nyob rau hauv qhov kub thiab txias. Kev khaws dej. Kev sib xyaw ntawm cov dej molecules thiab cellulose ether molecular saw hlau ua rau cov dej molecules nkag mus rau sab hauv ntawm cellulose ether macromolecular saw hlau thiab tau txais lub zog khi muaj zog, yog li tsim cov dej dawb, entangling dej, thiab txhim kho kev khaws dej ntawm cov cement slurry.

Ua kom tuab, thixotropic thiab tiv thaiv kev qaug zog: muab cov viscosity zoo heev rau cov mortar ntub! Nws tuaj yeem ua rau kom muaj kev sib txuas ntawm cov mortar ntub thiab cov txheej hauv paus, thiab txhim kho kev ua haujlwm tiv thaiv kev qaug zog ntawm cov mortar. Cov nyhuv thickening ntawm cellulose ethers kuj ua rau muaj kev tiv thaiv kev sib kis thiab kev sib xws ntawm cov khoom sib xyaw tshiab, tiv thaiv cov khoom delamination, sib cais thiab los ntshav. Cov nyhuv thickening ntawm cellulose ethers ntawm cov khoom siv cement los ntawm cov viscosity ntawm cellulose ether solutions. Nyob rau hauv tib lub xeev, qhov siab dua viscosity ntawm cellulose ether, qhov zoo dua viscosity ntawm cov khoom siv cement hloov kho, tab sis yog tias viscosity loj dhau, nws yuav cuam tshuam rau qhov fluidity thiab kev ua haujlwm ntawm cov khoom siv (xws li nplaum trowel thiab batch scraper). laborious). Self-leveling mortar thiab self-compacting concrete uas xav tau kev fluidity siab xav tau viscosity qis ntawm cellulose ether. Tsis tas li ntawd, cov nyhuv thickening ntawm cellulose ether yuav ua rau kom muaj dej ntau ntawm cov khoom siv cement thiab ua rau cov mortar ntau dua. Cov kua dej cellulose ether uas muaj viscosity siab muaj thixotropy siab, uas kuj yog ib qho tseem ceeb ntawm cellulose ether. Cov kua dej ntawm cellulose feem ntau muaj cov khoom ntws pseudoplastic, tsis yog thixotropic qis dua lawv qhov kub gel, tab sis cov khoom ntws Newtonian ntawm qhov nrawm qis. Pseudoplasticity nce nrog qhov hnyav molecular lossis concentration ntawm cellulose ether nce. Cov gels qauv tsim thaum qhov kub nce, thiab qhov ntws thixotropic siab tshwm sim. Cellulose ethers nrog cov concentration siab thiab viscosity qis qhia thixotropy txawm tias qis dua qhov kub gel. Cov khoom no muaj txiaj ntsig zoo rau kev tsim kho ntawm cov mortar tsev kom kho nws qhov leveling thiab sag. Nws yuav tsum tau sau tseg ntawm no tias qhov siab dua ntawm viscosity ntawm cellulose ether, qhov zoo dua qhov khaws cia dej, tab sis qhov siab dua ntawm viscosity, qhov siab dua ntawm qhov hnyav molecular ntawm cellulose ether, thiab qhov sib xws txo qis hauv nws cov solubility, uas muaj qhov cuam tshuam tsis zoo rau qhov concentration ntawm mortar thiab workability.

Ua rau: Cellulose ether muaj qhov cuam tshuam rau huab cua rau cov khoom siv cement tshiab. Cellulose ether muaj ob qho tib si hydrophilic pawg (hydroxyl pawg, ether pawg) thiab hydrophobic pawg (methyl pawg, glucose nplhaib), yog ib qho surfactant, muaj kev ua haujlwm ntawm qhov chaw, thiab yog li muaj qhov cuam tshuam rau huab cua. Qhov cuam tshuam rau huab cua ntawm cellulose ether yuav tsim cov nyhuv "pob", uas tuaj yeem txhim kho kev ua haujlwm ntawm cov khoom sib xyaw tshiab, xws li kev ua kom cov yas thiab du ntawm cov mortar thaum lub sijhawm ua haujlwm, uas yog qhov zoo rau kev paving ntawm cov mortar; nws tseem yuav ua rau cov zis ntawm cov mortar ntau ntxiv. , txo tus nqi ntawm kev tsim cov mortar; tab sis nws yuav ua rau cov porosity ntawm cov khoom tawv thiab txo nws cov khoom siv kho tshuab xws li lub zog thiab elastic modulus. Raws li ib tug surfactant, cellulose ether kuj muaj cov nyhuv ntub lossis lubricating rau cov cement, uas ua ke nrog nws cov nyhuv cua-entraining ua rau cov kua ntawm cov khoom siv cement ntau ntxiv, tab sis nws cov nyhuv thickening yuav txo qhov fluidity. Cov nyhuv ntawm kev ntws yog kev sib xyaw ua ke ntawm cov yas thiab cov nyhuv thickening. Thaum cov ntsiab lus ntawm cellulose ether qis heev, nws feem ntau yog pom tias yog cov yas lossis cov dej txo cov nyhuv; thaum cov ntsiab lus siab, cov nyhuv thickening ntawm cellulose ether nce sai, thiab nws cov nyhuv entraining feem ntau yuav saturated, yog li qhov kev ua tau zoo nce. Cov nyhuv thickening lossis kev thov dej ntau ntxiv.

Kev ncua sijhawm teeb tsa: Cellulose ether tuaj yeem ncua cov txheej txheem hydration ntawm cement. Cellulose ethers muab cov mortar nrog ntau yam khoom zoo, thiab tseem txo qhov tso tawm cua sov hydration thaum ntxov ntawm cov cement thiab ncua cov txheej txheem kinetic hydration ntawm cov cement. Qhov no tsis zoo rau kev siv mortar hauv thaj chaw txias. Qhov kev ncua sijhawm no yog tshwm sim los ntawm kev nqus ntawm cellulose ether molecules ntawm cov khoom hydration xws li CSH thiab ca (OH) 2. Vim yog qhov nce ntawm viscosity ntawm cov kua pore, cellulose ether txo qhov kev txav mus los ntawm cov ions hauv cov kua, yog li ncua cov txheej txheem hydration. Qhov siab dua qhov concentration ntawm cellulose ether hauv cov khoom siv mineral gel, qhov ntau dua qhov cuam tshuam ntawm hydration ncua sijhawm. Cellulose ethers tsis yog tsuas yog ncua kev teeb tsa, tab sis kuj tseem ncua cov txheej txheem hardening ntawm lub cev cement mortar. Qhov cuam tshuam retardation ntawm cellulose ether tsis yog nyob ntawm nws qhov concentration hauv lub cev mineral gel, tab sis kuj nyob ntawm cov qauv tshuaj. Qhov siab dua qib ntawm methylation ntawm HEMC, qhov zoo dua qhov cuam tshuam retardation ntawm cellulose ether. Qhov cuam tshuam retardation muaj zog dua. Txawm li cas los xij, qhov viscosity ntawm cellulose ether tsis muaj feem cuam tshuam rau qhov hydration kinetics ntawm cement. Nrog rau qhov nce ntawm cellulose ether cov ntsiab lus, lub sijhawm teeb tsa ntawm mortar nce ntxiv ntau heev. Muaj kev sib raug zoo nonlinear ntawm lub sijhawm teeb tsa thawj zaug ntawm mortar thiab cov ntsiab lus ntawm cellulose ether, thiab lub sijhawm teeb tsa kawg muaj kev sib raug zoo linear nrog cov ntsiab lus ntawm cellulose ether. Peb tuaj yeem tswj lub sijhawm ua haujlwm ntawm mortar los ntawm kev hloov cov ntsiab lus ntawm cellulose ether. Hauv cov khoom, nws ua lub luag haujlwm ntawm kev khaws dej, thickening, ncua lub zog cement hydration, thiab txhim kho kev ua haujlwm ntawm kev tsim kho. Lub peev xwm khaws dej zoo ua rau cement gypsum tshauv calcium teb tau zoo dua, ua rau cov viscosity ntub ntau ntxiv, txhim kho lub zog sib txuas ntawm mortar, thiab tib lub sijhawm tuaj yeem txhim kho lub zog tensile thiab shear zog, txhim kho kev tsim kho zoo heev thiab kev ua haujlwm zoo. Lub sijhawm hloov kho tau. Txhim kho kev tsuag lossis pumpability ntawm mortar, nrog rau lub zog ntawm cov qauv. Hauv cov txheej txheem thov tiag tiag, nws yog qhov tsim nyog los txiav txim siab hom, viscosity, thiab ntau npaum li cas ntawm cellulose raws li cov khoom sib txawv, kev coj ua hauv kev tsim kho, thiab ib puag ncig.