1. Chidule cha cellulose ether (HPMC)
Hydroxypropyl methylcellulose (HPMC) ndi chinthu chomwe chimagwiritsidwa ntchito kwambiri pa cellulose ether, chomwe chimasinthidwa kuchokera ku cellulose yachilengedwe. Ili ndi madzi abwino kwambiri osungunuka, kupanga mafilimu, kukhuthala ndi zomatira, choncho amagwiritsidwa ntchito kwambiri pomanga zipangizo. Kugwiritsiridwa ntchito kwa HPMC pazida zopangira simenti makamaka kumapangitsa kuti madzi azisungunuka, kusunga madzi ndikusintha nthawi yokhazikitsa.
2.Basic ndondomeko yoyika simenti
Njira yochitira simenti ndi madzi kuti ipange ma hydrates imatchedwa hydration reaction. Njirayi imagawidwa m'magawo angapo:
Nthawi yopangira simenti: Tinthu tating'ono ta simenti timayamba kusungunuka, kupanga ayoni a calcium ndi ayoni a silicate, kuwonetsa kutsika kwakanthawi kochepa.
Nthawi yofulumizitsa: Zogulitsa zamagetsi zimachulukirachulukira ndipo njira yokhazikitsira imayamba.
Nthawi yochepetsera: Kuchuluka kwa hydration kumachepa, simenti imayamba kuuma, ndipo mwala wolimba wa simenti umapangidwa.
Nthawi yokhazikika: Zinthu za hydration zimakhwima pang'onopang'ono ndipo mphamvu zimawonjezeka pang'onopang'ono.
Nthawi yoyika nthawi zambiri imagawidwa kukhala nthawi yoikika yoyambira ndi nthawi yomaliza. Nthawi yoyika koyamba imatanthawuza nthawi yomwe phala la simenti limayamba kutaya pulasitiki, ndipo nthawi yomaliza yoyika imatanthawuza nthawi yomwe phala la simenti limataya pulasitiki ndikulowa mu siteji yowumitsa.
3. Njira ya chikoka cha HPMC pa nthawi yoyika simenti
3.1 Kukulitsa zotsatira
HPMC ali kwambiri thickening kwenikweni. Zitha kuonjezera mamasukidwe akayendedwe a simenti phala ndi kupanga mkulu-kukhuthala dongosolo. Izi thickening zotsatira zidzakhudza kubalalitsidwa ndi sedimentation wa simenti particles, motero zimakhudza patsogolo hydration anachita. The thickening zotsatira amachepetsa mafunsidwe mlingo wa mankhwala hydration padziko simenti particles, potero kuchedwetsa kuika nthawi.
3.2 Kusunga madzi
HPMC ili ndi mphamvu yosungira madzi yabwino. Kuonjezera HPMC ku phala la simenti kungathandize kwambiri kusunga madzi kwa phala. Kusunga madzi ochulukirapo kumatha kulepheretsa madzi pamwamba pa simenti kuti asasunthike mwachangu, kuti asunge madzi omwe ali mu phala la simenti ndikutalikitsa nthawi ya hydration. Kuphatikiza apo, kusungirako madzi kumathandizira phala la simenti kukhalabe ndi chinyezi choyenera panthawi yochiritsa komanso kuchepetsa chiopsezo chosweka chifukwa cha kutaya madzi koyambirira.
3.3 Kuchepetsa kwa hydration
HPMC akhoza kupanga filimu zoteteza kuphimba pamwamba pa simenti particles, amene angalepheretse hydration anachita. Filimu yotetezayi imalepheretsa kukhudzana kwachindunji pakati pa tinthu tating'ono ta simenti ndi madzi, potero kuchedwetsa njira ya hydration ya simenti ndikutalikitsa nthawi yokhazikitsa. Kuchedwa kumeneku kumawonekera makamaka mu HPMC yolemera kwambiri.
3.4 Kupititsa patsogolo thixotropy
Kuwonjezera kwa HPMC kungathandizenso thixotropy wa simenti slurry (ie, fluidity ukuwonjezeka pansi pa zochita za kunja mphamvu ndi kubwerera ku chiyambi boma pambuyo kunja mphamvu kuchotsedwa). Izi thixotropic katundu kumathandiza kusintha workability wa simenti slurry, koma mawu a kuika nthawi, izi kumatheka thixotropy zingachititse slurry redistribute pansi kukameta ubweya mphamvu, zina kutalikitsa kuika nthawi.
4. Kugwiritsa ntchito bwino kwa HPMC kukhudza nthawi yoyika simenti
4.1 Zida zodziyimira pawokha
Pazida zodziyimira pawokha, simenti imafuna nthawi yayitali yokhazikitsa kuti isamalire ndi kupukuta. Kuwonjezera HPMC kumatha kutalikitsa nthawi yoyambira simenti, kulola kuti zida zodzipangira zokha zikhale ndi nthawi yayitali yogwira ntchito pomanga, kupeŵa vuto lomwe limabwera chifukwa cha slurry ya simenti nthawi yomanga.
4.2 Mtondo wosakanikirana
Mu matope osakanikirana, HPMC sikuti imangowonjezera kusungidwa kwamadzi mumatope, komanso imatalikitsa nthawi yokhazikitsa. Izi ndizofunikira makamaka pazochitika zomwe zimakhala ndi nthawi yayitali ya mayendedwe ndi nthawi yomanga, kuwonetsetsa kuti matope akugwira ntchito bwino musanagwiritse ntchito komanso kupewa zovuta zomanga zomwe zimachitika chifukwa cha nthawi yochepa kwambiri.
4.3 Mtondo wosakanizika wowuma
HPMC nthawi zambiri imawonjezedwa kumatope osakanikirana kuti apititse patsogolo ntchito yake yomanga. Kukhuthala kwa HPMC kumawonjezera kukhuthala kwa matope, kupangitsa kuti ikhale yosavuta kugwiritsa ntchito komanso kusanja pakumanga, komanso kumatalikitsa nthawi yokhazikitsa, kupatsa ogwira ntchito yomanga nthawi yokwanira kuti asinthe.
5. Zomwe zimakhudza nthawi yoyika simenti ndi HPMC
5.1 HPMC yowonjezera ndalama
Kuchuluka kwa HPMC yowonjezeredwa ndi chinthu chofunikira chomwe chimakhudza nthawi yoyika simenti. Nthawi zambiri, kuchuluka kwa HPMC kuonjezeredwa, ndikodziwikiratu kukulitsa nthawi yoyika simenti. Izi ndichifukwa choti mamolekyu ochulukirapo a HPMC amatha kuphimba tinthu tambiri ta simenti ndikulepheretsa ma hydration.
5.2 Kulemera kwa molekyulu ya HPMC
HPMC ya zolemera zosiyanasiyana maselo ali ndi zotsatira zosiyana pa kuika nthawi simenti. HPMC yokhala ndi kulemera kwakukulu kwa maselo nthawi zambiri imakhala ndi kukhuthala kwamphamvu komanso mphamvu yosungira madzi, kotero imatha kutalikitsa nthawi yokhazikika kwambiri. Ngakhale HPMC yokhala ndi kulemera kochepa kwa maselo imathanso kutalikitsa nthawi yokhazikitsa, zotsatira zake zimakhala zofooka.
5.3 Mikhalidwe ya chilengedwe
Kutentha kozungulira ndi chinyezi kudzakhudzanso mphamvu ya HPMC pa nthawi yoyika simenti. M'malo otentha kwambiri, simenti ya hydration imachulukitsidwa, koma katundu wosungira madzi wa HPMC amachepetsa izi. M'malo otentha otsika, hydration reaction palokha imachedwa, ndipo kukhuthala ndi kusunga madzi kwa HPMC kungapangitse nthawi yoyika simenti kuti italike kwambiri.
5.4 Madzi a simenti
Kusintha kwa chiŵerengero cha simenti ya madzi kudzakhudzanso zotsatira za HPMC pa nthawi yoyika simenti. Pachiŵerengero chapamwamba cha simenti yamadzi, pali madzi ambiri mu phala la simenti, ndipo mphamvu yosungira madzi ya HPMC ikhoza kukhala ndi zotsatira zochepa pa nthawi yokhazikitsa. Pachiŵerengero chochepa cha simenti yamadzi, kuwonjezereka kwa HPMC kudzakhala koonekeratu, ndipo zotsatira za kukulitsa nthawi yokhazikika zidzakhala zofunikira kwambiri.
Monga chowonjezera chowonjezera cha simenti, HPMC imakhudza kwambiri nthawi yoyika simenti kudzera m'njira zosiyanasiyana monga kukhuthala, kusunga madzi, ndi kuchepa kwa hydration reaction. Kugwiritsa ntchito kwa HPMC kumatha kutalikitsa nthawi yoyambira komanso yomaliza ya simenti, kupereka nthawi yayitali yomanga, ndikuwongolera magwiridwe antchito a simenti. Muzochita zogwiritsidwa ntchito, zinthu monga kuchuluka kwa HPMC yowonjezeredwa, kulemera kwa maselo, ndi zochitika zachilengedwe pamodzi zimatsimikizira zotsatira zake pa nthawi yoyika simenti. Mwa kuwongolera zinthu izi moyenera, kuwongolera bwino nthawi yoyika simenti kungatheke kukwaniritsa zosowa zamitundu yosiyanasiyana yomanga.
Nthawi yotumiza: Jun-21-2024