Kev Ntsuas Kev Ntsuas Ntawm Polycarboxylate Acid Superplasticizer

Polycarboxylate superplasticizers rau kev ua haujlwm siab ua haujlwm feem ntau ua haujlwm los ntawm copolymerization ntawm unsaturated monomers nyob rau hauv qhov kev txiav txim ntawm cov neeg pib, grafting sab chains nrog reactive pawg mus rau lub ntsiab saw ntawm polymers. Qhov no tso cai rau lawv nrog kev ua haujlwm siab, tswj kev poob qis thiab shrinkage tsis kam, thiab tsis muaj kev cuam tshuam rau cov cement qhov chaw thiab hardening. Polycarboxylate superplasticizers yog txawv kiag li ntawm naphthalene sulfonate formaldehyde condensates (NSF) thiab melamine sulfonate formaldehyde condensates (MSF) superplasticizers. Txawm tias tsawg npaum li cas, lawv tuaj yeem muab cov kua dej ntau rau cov pob zeb thiab tswj kom tsis muaj viscosity thiab slump tuav ntawm cov dej-cement ratios tsawg. Lawv muaj qhov zoo sib xws nrog cov cements sib txawv thiab yog cov khoom siv tsis tseem ceeb rau kev ua kom muaj zog, siab-fluidity pob zeb.

Dej txo mechanism

Polycarboxylic acid superplasticizer yog synthesized los ntawm grafting active pab pawg nrog sib txawv zog mus rau lub ntsiab saw raws li DLVO nqi repulsion txoj kev xav thiab steric hindrance nyhuv txoj kev xav siv molecular qauv tsim qauv. Cov saw tseem ceeb ntawm polycarboxylic acid ua haujlwm siab dej txo tus neeg sawv cev molecules yog ruaj khov adsorbed rau saum npoo ntawm cov cement hais, uas tuaj yeem cuam tshuam cov tshuaj tiv thaiv dej thiab txhim kho nws cov yas tuav, thaum cov ceg saw yog nyob ib puag ncig ntawm cov cement hais, ua si ob lub luag haujlwm ntawm steric. hindrance thiab electrostatic repulsion, uas yog txawv kiag li los ntawm cov txheej txheem ntawm tsoos dej txo tus neeg saib xyuas dispersing cement hais los ntawm electrostatic repulsion, yog li nws muaj peev xwm dispersion zoo dua thiab dej txo cov nyhuv. Thaum kawg, kev ua tau zoo ntawm cov khoom siv pob zeb tau ua qhov zoo tshaj plaws.

Homogeneity tsom xam

Table 1 Homogeneity Performance index ntawm polycarboxylic acid superplasticizer

Table 2 Uniformity Performance index ntawm naphthalene superplasticizer

Raws li tau pom los ntawm Table 1, polycarboxylic acid superplasticizer puag muaj cov ntsiab lus qis thiab tsis muaj cov tshuaj chloride ions, uas zoo heev txhim kho lub durability ntawm pob zeb thiab yog ib qho tseem ceeb hauv kev npaj cov pob zeb ua haujlwm ntsuab.

Khoom kom zoo dua

• Cov dej txo qis: polycarboxylic acid siab ua haujlwm dej txo cov dej txo tus nqi txog li 25-40%.
• High zog loj hlob tus nqi: siab zog loj hlob tus nqi, tshwj xeeb tshaj yog nyob rau hauv thaum ntxov lub zog loj hlob tus nqi.
• Kev tuav pov hwm zoo heev: kev ua haujlwm ruaj khov zoo heev, uas tuaj yeem ua kom lub sijhawm poob qis ntawm cov pob zeb.
• Zoo homogeneity: cov pob zeb muaj fluidity zoo heev, yooj yim rau cam khwb cia thiab compacted, haum rau tus kheej-leveling thiab nws tus kheej-compacting pob zeb.
• Kev tswj hwm ntau lawm: cov dej txo qis, cov yas tuav thiab cov cua nkag tau zoo ntawm cov dej reducer no tuaj yeem hloov kho los ntawm kev kho qhov hnyav molecular ntawm cov polymer, qhov ntev thiab qhov ntom ntom ntawm cov saw hlau sab thiab hom sab saw pawg.
• Kev hloov dav dav: txhua yam ntawm silicon ntshiab, silicon dav dav, slag Portland cement thiab ntau yam admixtures ua los ntawm pob zeb muaj qhov zoo dispersion thiab tuav yas.
• Tsawg shrinkage: nws tuaj yeem txhim kho qhov ntim ruaj khov ntawm cov pob zeb, thiab txo qis 28d shrinkage ntawm naphthalene superplasticizer pob zeb los ntawm 20%, zoo txo ​​qhov kev puas tsuaj los ntawm pob zeb tawg.
• Kev tiv thaiv ib puag ncig ntsuab: tsis muaj tshuaj lom, tsis muaj corrosive, tsis muaj formaldehyde thiab lwm yam khoom xyaw.