Focus on Cellulose ethers

I-Cellulose ether ibuyisela ukuqina kukasimende

I-Cellulose ether iwuhlobo lwenhlanganisela ye-organic polymer esetshenziswa kakhulu ezintweni zokwakha, ikakhulukazi ezintweni ezisekelwe kusimende. I-Cellulose ether ingabambezela inqubo ye-hydration kasimende, ngaleyo ndlela ilungise ukusebenza, ukusetha isikhathi kanye nokuthuthukiswa kwamandla okuqala okunamathiselwe kukasimende.

(1). Ukusabela okubambezelekile kwe-hydration
I-Cellulose ether ingabambezela ukusabela kwe-hydration kasimende, okutholakala kakhulu ngokusebenzisa lezi zindlela ezilandelayo:

1.1 I-Adsorption nemiphumela yokuvikela
Isixazululo se-viscosity esiphezulu esakhiwe ngokuncibilikisa i-cellulose ether esixazululweni samanzi singakha ifilimu ye-adsorption ebusweni bezinhlayiya zikasimende. Ukwakheka kwale filimu kubangelwa ikakhulukazi ukukhangiswa ngokomzimba kwamaqembu e-hydroxyl kuma-molecule e-cellulose ether nama-ion ebusweni bezinhlayiya zikasimende, okuholela ekutheni izinhlayiya zikasimende zivikeleke, kunciphisa ukuthintana phakathi kwezinhlayiya zikasimende nama-molecule amanzi, ngaleyo ndlela. ukubambezela ukusabela kwe-hydration.

1.2 Ukwakhiwa kwefilimu
Ezigabeni zokuqala ze-cement hydration, i-cellulose ether ingakha ifilimu eliminyene ebusweni bezinhlayiya zikasimende. Ukuba khona kwale filimu kuvimbela ngempumelelo ukusakazeka kwama-molecule amanzi ngaphakathi kwezinhlayiya zikasimende, ngaleyo ndlela kubambezeleka izinga lokugeleza kukasimende. Ngaphezu kwalokho, ukwakheka kwale filimu kunganciphisa nokuhlakazeka nokusabalalisa kwe-calcium ions, kubambezeleke nakakhulu ukwakheka kwemikhiqizo ye-hydration.

1.3 Ukuhlakazeka nokudedelwa kwamanzi
I-cellulose ether inokumunca amanzi okuqinile, ingakwazi ukumunca umswakama futhi iwukhulule kancane. Le nqubo yokukhishwa kwamanzi ingalungisa uketshezi nokusebenza kwe-cement slurry ngokwezinga elithile, futhi ibambezele izinga lokusabela kwe-hydration ngokunciphisa ukugxila okusebenzayo kwamanzi ngesikhathi senqubo ye-hydration.

(2). Umthelela wokwakheka kwesigaba sikasimende
Ama-cellulose ethers anemiphumela ehlukene ku-hydration yezigaba ezahlukene zikasimende. Ngokuvamile, i-cellulose ether inomphumela osobala kakhudlwana ku-hydration ye-tricalcium silicate (C₃S). Ukuba khona kwe-cellulose ether kuzobambezela ukugeleza kwe-C₃S futhi kunciphise izinga lokukhululwa kokushisa kwe-hydration kwangaphambi kwesikhathi kwe-C₃S, ngaleyo ndlela kubambezele ukuthuthukiswa kwamandla okuqala. Ukwengeza, i-cellulose ethers ingaphinde ithinte ukugeleza kwezinye izingxenye zamaminerali ezifana ne-dicalcium silicate (C₂S) ne-tricalcium aluminate (C₃A), kodwa le miphumela mincane kakhulu.

(3). I-Rheology nemiphumela yesakhiwo
I-Cellulose ether ingakhuphula i-viscosity ye-cement slurry futhi ithinte i-rheology yayo. I-viscosity slurry ephezulu isiza ukunciphisa ukumisa kanye nokuhlelwa kwezinhlayiya zikasimende, okuvumela udaka lukasimende ukuthi lugcine ukufana okuhle ngaphambi kokumiswa. Lesi sici se-viscosity esiphezulu asigcini nje ukubambezela inqubo ye-hydration kasimende, kodwa futhi sithuthukisa ukusebenza kwe-fluidity nokwakhiwa kwe-cement slurry.

(4). Imiphumela yohlelo lokusebenza nezinyathelo zokuphepha
Ama-cellulose ethers anomphumela obalulekile ekubambezeleni ukugeleza kukasimende futhi ngakho-ke avame ukusetshenziselwa ukulungisa isikhathi sokumisa kanye noketshezi lwezinto ezisekelwe kusimende. Kodwa-ke, umthamo kanye nohlobo lwe-cellulose ether kudingeka kulawulwe ngokunembile, ngoba i-cellulose ether eyeqile ingase ibangele izinkinga ezifana nokunganeli kwamandla okuqala kanye nokwenyuka kokuncipha kwezinto ezisekelwe kusimende. Ukwengeza, izinhlobo ezahlukene ze-cellulose ethers (ezifana ne-methylcellulose, i-hydroxypropylmethylcellulose, njll.) zinezinqubo nemiphumela ehlukene kuma-slurries kasimende, futhi zidinga ukukhethwa ngokuvumelana nezidingo ezithile zohlelo lokusebenza.

Ukusetshenziswa kwe-cellulose ether ezintweni ezisekelwe kusimende akukwazi nje ukubambezela ngokuphumelelayo ukusabela kwe-hydration kasimende, kodwa futhi kuthuthukise ukusebenza kokwakhiwa nokuqina kwempahla. Ngokukhetha okunengqondo nokusetshenziswa kwama-cellulose ethers, ikhwalithi nomphumela wokwakha wezinto ezisekelwe kusimende zingathuthukiswa kakhulu.


Isikhathi sokuthumela: Aug-03-2024
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