HPMC (HydroxyPropyyl methyl cellulose) yog cov khoom siv polymer feem ntau siv nyob rau hauv cov ntaub ntawv hauv tsev, tshwj xeeb yog cov khoom noj thiab cov khoom siv gypsum. Nws muaj cov dej ua kom zoo, cov dej nplaum, ua kom muaj zog, yog li nws tau siv dav hauv cov hmoov sib tov, putty hmoov, nplais nplaum thiab lwm yam khoom.
1. Cov teeb meem ntawm shrinkage thiab tawg ntawm cov ntaub ntawv tsim tsev
Thaum lub sij hawm ua kom tawv nqaij tawv, cov khoom siv hauv tsev feem ntau yuav tawg, tshuaj lom neeg cov kev siv tshuaj thiab hloov pauv hauv kev nyuaj siab ib puag ncig thiab tawg tsim. Lub ntsiab ntawm shrinkage xws li:
Yas Shrinkage: Thaum cov khoom siv xas-raws li cov khoom siv tsis tau, lub ntim shrined, lub ntim shrinks vim yog dej evaporation sai sai.
Qhuav shrinkage: tom qab cov khoom tawv, nws raug rau huab cua ntev ntev, thiab cov dej maj mam, uas ua rau ntim shrinkage.
Qhov kub txav: ntim hloov vim los ntawm qhov kub hloov, tshwj xeeb tshaj yog nyob hauv ib puag ncig nrog qhov sib txawv loj ntawm nruab nrab hnub thiab hmo ntuj.
Autoogenous Shrinkage: Thaum lub tshuab ua kom cov txiv duaj txoj kev noj qab haus huv, cov ntim sab hauv vim kev siv dej los ntawm cov tshuaj tsw qab.
Cov shrinkages feem ntau ua rau kev ntxhov siab ntxiv sab hauv cov khoom, thaum kawg ua rau cov micrmacks lossis cov kab nrib pleb, uas cuam tshuam rau lub tsev qauv. Txhawm rau zam dhau qhov tshwm sim no, ntxiv feem ntau xav tau los txhim kho kev ua haujlwm ntawm cov khoom, thiab HPMC yog ib qho ntawm lawv.
2. Mechanism ntawm kev ua ntawm HPMC
HPMC ua si lub luag haujlwm tseem ceeb hauv kev txo cov ntaub ntawv pov tseg thiab tawg ntawm cov ntaub ntawv hauv tsev, uas yog ua tiav los ntawm cov txheej txheem hauv qab no:
Dej khaws cia: HPMC muaj lub zog ua kom muaj zog Txij li thaum cov dej evaporation so hauv cov khoom yuav ua rau cov khoom siv tsis zoo, yog li kev txhawb nqa cov tshuaj tsw qab thaum ntxov, yog li txo cov shrinkage tawg los ntawm dej poob thaum lub sijhawm ua kom qhuav. Tsis tas li ntawd, HPMC tuaj yeem txhim kho kev ua tau zoo ntawm cov khoom siv nyob rau hauv av ntub thiab qhuav thiab txo cov kev tawg los ntawm dej poob.
Thickening thiab ntxiv dag zog rau cov nyhuv: HPMC yog qhov tuab uas tuaj yeem ua kom zoo sib xws thiab viscoity ntawm cov nplaum tag nrho thiab txhim kho cov nplaum tag nrho ntawm cov khoom siv. Thaum lub sij hawm tsim kho, yog tias cov khoom siv yog qhov yooj yim dhau, nws yog qhov yooj yim rau Delaminate lossis Sag, ua rau muaj kev sib tsoo ntawm qhov chaw tsis ncaj lossis tawg. Los ntawm kev siv HPMC, cug lub cap tuaj yeem tswj cov viscosity tsim nyog, txhim kho lub zog thiab qhov ntom ntom ntawm cov khoom siv tom qab kev tsim kho, thiab txo cov peev txheej ntawm kev tawg. Tsis tas li ntawd, HPMC kuj tseem tuaj yeem txhim kho cov shear tsis kam ntawm cov khoom thiab txhim kho nws cov kev tawg tawm.
Txhim kho qhov yooj yim ntawm cov khoom siv: HPMC Molecules tuaj yeem ua lub luag haujlwm hauv kev txhim kho cov khoom siv lossis cov khoom siv tau zoo dua thiab khoov tsis zoo tom qab kho tau. Txij li thaum cov ntaub ntawv hauv tsev feem ntau yog ua rau tensile lossis bending kev ntxhov siab nyob rau hauv huab cua kub hloov, tom qab ntxiv cov kev ntxhov siab sab nraud thiab zam kev sib tsoo.
Tswj lub Maas Ifized cov tshuaj tiv thaiv cov tshuaj tiv thaiv kab ke, qhov ceev ntawm cov dej qab ntawm tus nqi ncaj qha cuam tshuam rau cov khoom siv ntawm cov khoom siv. Yog tias cov tshuaj dej ntws nrawm nrawm dua, cov kev ntxhov siab sab hauv cov khoom siv tsis tuaj yeem tso tawm hauv lub sijhawm, ua rau muaj kev tawg. HPMC tuaj yeem hloov kho kom qeeb tus nqi ntawm kev ua yeeb yam ntawm kev ua yeeb yam ntawm kev ua yeeb yam ntawm kev ua yeeb yam ntawm kev poob qis thiab tawg thaum ntxov thaum lub sij hawm tawv ntawm cov txheej txheem tawv ntawm cov khoom.
Txhim kho kev tsim kho kev tsim kho: HPMC tuaj yeem txhim kho cov ntaub ntawv tsim kho hauv tsev, kev ua kom zoo, nce kev sib tw, thiab txo cov kab nrib pleb tshwm sim los ntawm kev tsim kho. Nws tuaj yeem ua tshuaj cug, ua kom muaj hmoov, ua kom yooj yim dua thiab muaj zog ntawm cov ntaub ntawv, thiab txo cov kev pheej hmoo ntawm cov khoom tawg hauv zos los ntawm kev tsim kho tsis sib xws.
3. Daim ntawv thov ntawm HPMC hauv cov ntaub ntawv hauv tsev tshwj xeeb
Pobzeb nplaum: HPMC muaj peev xwm txhim kho kev ua yeeb yam los tiv thaiv pobzeb Ib qho ntxiv, cov thickening thiab dej khaws cov teebmeem ntawm HPMC kuj pab tau cov khoom siv qhib, txhim kho kev ua haujlwm ntev dua, thiab txo cov kab nrib pleb los ntawm kev kho tsis ncaj.
Putty Hmoov: Hauv cov khoom siv putty, cov dej khaws cia ntawm HPMC tuaj yeem tiv thaiv kom tsis txhob muaj dej kom qhuav, thiab txo cov txheej txheem shrinkage thiab tawg tshwm sim los ntawm dej poob. Nyob rau tib lub sijhawm, cov nyhuv tuab ntawm HPMC tuaj yeem txhim kho kev tsim kho kev tsim kho ntawm putty, ua rau nws yooj yim dua rau covyees ntawm phab ntsa, thiab txo qhov chaw mos los ntawm qhov tsis sib xws.
Tshuaj khib: Ntxiv HPMC rau tshuaj khib yuav hloov tau nws txoj kev ua haujlwm zoo thiab kev ua haujlwm, thiab yog li txhim kho cov kev sib xyaw thiab cov nplaum ntawm lub tshuaj khib. Nyob rau tib lub sijhawm, cov dej khaws cia hauv HPMC tuaj yeem ua rau cov dej yaj ntawm cov txheej txheem tawv me me, zam kev ua kom tawv thiab tawg ua los ntawm cov dej ntxov.
4. Kev ceev faj rau kev siv HPMC
Kev tswj ntau npaum li cas: Tus nqi HPMC ntxiv muaj qhov cuam tshuam ncaj qha rau nws cov nyhuv, thiab nws feem ntau yuav tsum tau hloov kho raws li cov khoom sib piv thiab cov ntawv thov tshwj xeeb. Ntau HPMC yuav ua rau cov khoom siv kom muaj kev sib xws heev, cuam tshuam rau kev ua haujlwm; Thaum tsis txaus HPMC yuav tsis tuaj yeem ua lub luag haujlwm ntawm dej khaws cia thiab ua kom tuab li yuav tsum ua.
Siv nrog lwm cov tshuaj sib ntxiv: HPMC feem ntau yog siv rau hauv kev sib xyaw ua ke nrog lwm cov dej sib ntxiv (xws li cov dej txo qis, huab cua nkag, thiab lwm yam) kom ua tiav cov txiaj ntsig zoo dua. Thaum siv, nws yog ib qho tsim nyog los txiav txim siab txog kev sib txawv ntawm cov sib txawv sib txawv kom tsis txhob muaj kev sib raug zoo ntawm cov ntaub ntawv.
Raws li lub tsev tseem ceeb ntxiv, HPMC muaj qhov cuam tshuam tseem ceeb hauv kev txo cov vrinkage thiab tawg ntawm cov ntaub ntawv tsev. Nws ua tau zoo txo cov kab nrib pleb tshwm sim los ntawm cov dej poob thiab kev ntxhov siab los ntawm kev txhim kho cov dej khaws cia, kom yooj ntawm cov khoom noj thiab kev txhim kho cov khoom noj kom xis. Kev siv HPMC tsim nyog tsis tuaj yeem txhim kho kev tsim kho ntawm cov khoom siv, tab sis kuj txuas ntxiv kev pabcuam lub neej ntawm lub tsev qauv thiab txo tus nqi tom qab txij nkawm. Nrog rau kev nce qib nruam ntawm kev siv tshuab kev ua haujlwm, kev thov ntawm HPMC hauv kev tsim kho teb yuav muaj ntau ntau thiab tob tob.
Lub Sijhawm Post: Sep-21-2024