Cov tshuaj phom sij thiab kev tiv thaiv siv hauv Kev Tsim Cov Polycarboxylic Acid Superplasticizers

Nyob rau hauv cov txheej txheem synthesis ntawm polycarboxylate superplasticizers, cov khoom siv raw siv suav nrog cov neeg pib, cov monomers me me, cov saw hloov cov neeg ua haujlwm, thiab caustic soda flakes. Cov neeg pib yog cov persulfates thiab peroxides, feem ntau siv cov hydrogen peroxide (H2O2) thiab ammonium persulfate [(NH4) 2S2O8]. Feem ntau siv me me monomers yog acrylic acid thiab hydroxyethyl acrylate. Cov saw hlau hloov pauv uas muaj xws li mercaptoethanol thiab mercaptoacetic acid.

3.1 Cov Thawj Coj

Cov neeg pib siv cov tshuaj tiv thaiv polymerization ntawm polycarboxylate superplasticizers feem ntau yog peroxides thiab persulfates, feem ntau hydrogen peroxide (H2O2) thiab ammonium persulfate [(NH4) 2S2O8], uas yog cov muaj zog oxidizing cov neeg ua haujlwm uas decompose yooj yim thaum rhuab. Lawv yog siv nyob rau hauv lub polymerization thiab copolymerization ntawm vinyl radicals nyob rau hauv polycarboxylate superplasticizers. Tus pib yog ib qho tseem ceeb raw khoom nyob rau hauv synthesis ntawm cov dej-txo cov neeg ua hauj. Nws qhov ntau npaum li cas cuam tshuam cov saw ntev thiab qhov hnyav molecular ntawm superplasticizer, thiab cov saw hlau ntev yog tsim nyog rau kev ua haujlwm zoo tshaj plaws ntawm superplasticizer.

Txij li thaum ob qho tib si hydrogen peroxide thiab ammonium persulfate yog corrosive, kev nyab xeeb yuav tsum tau ua kom ntseeg tau thaum lub sij hawm tsim khoom thaum tau txais cov khoom zoo polycarboxylate superplasticizers.

Hydrogen peroxide yog ib qho oxidizer heev. Nws yog non-flammable tab sis reacts nrog combustible cov ntaub ntawv, tso ib tug loj npaum li cas ntawm tshav kub thiab oxygen, uas yuav ua rau hluav taws kub los yog tawg. Nws yog qhov ruaj khov tshaj plaws ntawm pH ntawm 3.

Ammonium persulfate yog corrosive thiab irritating thiab tuaj yeem ua rau hlawv rau tib neeg lub cev. Nws tuaj yeem tawg thaum raug tshav kub lossis cuam tshuam thiab tsim cov khoom tawg nrog cov neeg ua haujlwm txo qis, cov khoom siv organic, lossis cov khoom tawg yooj yim. Ammonium persulfate kuj tseem siv tau los tsim hydrogen peroxide. Hauv kev tsim cov polycarboxylate superplasticizers, ammonium persulfate los yog hydrogen peroxide yog siv los ua ib qho kev pab cuam rau induce lub polymerization ntawm me me monomers. Hauv kev kuaj sim, pub mis, thiab khaws cia, cov khoom siv tiv thaiv tus kheej yuav tsum hnav, nrog rau cov hnab looj tes roj hmab, tsom iav tiv thaiv tshuaj lom neeg, thiab hnav khaub ncaws ua haujlwm tiv thaiv kom tsis txhob raug mob. Yog tias nws cuam tshuam rau ntawm daim tawv nqaij, nws yuav tsum tau yaug tam sim ntawd nrog dej.

3.2 Me Monomers

Ntau hom me me monomers yog siv los tsim cov polycarboxylate superplasticizers, uas feem ntau siv yog acrylic acid thiab hydroxyethyl acrylate. Acrylic acid yog cov khoom siv tseem ceeb rau polycarboxylate superplasticizers. Nws yog ib qho ceev-polymerizing vinyl monomer thiab yooj yim tshaj unsaturated carboxylic acid. Raws li ib tug me me molecule monomer, nws reacts nrog loj monomers, tsim ib tug comb-zoo li molecular qauv nyob rau hauv lub cuam tshuam ntawm cov saw hloov neeg sawv cev.

Acrylic acid muaj zog acidic thiab corrosive, nrog cov tshuaj muaj zog heev. Nws cov vapors ua rau tawg sib xyaw nrog huab cua, uas tuaj yeem ua rau tawg lossis tawg thaum raug nplaim taws lossis kub kub. Nws reacts hnyav nrog oxidizing tus neeg sawv cev. Qhov kub thiab txias tuaj yeem ua rau cov tshuaj tiv thaiv polymerization, tso tawm ntau cov cua sov, ua rau lub thawv ntim khoom tawg thiab tawg tawg [4].

Hydroxyethyl acrylate tuaj yeem npaj los ntawm acrylic acid thiab ethylene oxide nyob rau hauv qhov kev txiav txim ntawm catalyst. Nws lub luag haujlwm hauv polycarboxylate superplasticizers zoo ib yam li cov acrylic acid, tab sis siv acrylic acid ncaj qha tuaj yeem txo cov qib ntau lawm, thiab nws feem ntau ua tau zoo dua rau cov chaw tsim tshuaj lom neeg xaiv acrylic acid rau kev lag luam zoo dua.

Ob leeg yog cov kua tshuaj lom thiab corrosive, muaj cov tshuaj lom neeg ua haujlwm. Kev tiv thaiv yuav tsum tau ua thaum tsim cov polycarboxylate superplasticizers. Cov kev ceev faj tshwj xeeb muaj xws li:

1. Thaum cov concentration hauv huab cua tshaj qhov txwv, hnav lub npog ntsej muag roj; Thaum muaj xwm txheej ceev, siv lub tshuab ua pa rau tus kheej kom cawm lossis khiav tawm.
2. Hnav cov tsom iav tiv thaiv chemical.
3. Hnav cov khaub ncaws tiv thaiv ua los ntawm cov khoom siv tiv thaiv corrosion.
4. Hnav hnab looj tes roj hmab.
5. Tom qab ua haujlwm, da dej thiab hloov khaub ncaws, ua tib zoo saib xyuas tus kheej.

3.3 Chain Transfer Agents

Thiols feem ntau yog siv los ua cov saw hlau hloov pauv hauv kev sib txuas ntawm polycarboxylate superplasticizers, xws li mercaptoethanol thiab mercaptoacetic acid. Cov saw hlau hloov pauv tsis cuam tshuam rau cov tshuaj tiv thaiv ceev ntawm polycarboxylate superplasticizer synthesis tab sis tswj qhov ntev ntawm cov saw hlau polymer thiab tuaj yeem hloov cov dawb radicals zoo. Feem ntau, ua kom ntau npaum li cas ntawm cov saw hloov cov neeg sawv cev luv luv ntawm cov saw hlau polymer thiab txo cov viscosity.

Ob leeg mercaptoacetic acid thiab mercaptoethanol muaj thiol pawg thiab yog cov kua tshuaj lom heev nrog cov ntxhiab tsw ntxhiab. Lawv tuaj yeem ua rau tawg thaum raug hluav taws kub los yog kub kub thiab tsim cov pa phem sulfurous thaum decomposed los ntawm tshav kub. Lawv yog cov corrosive heev. Kev ntsuas kev nyab xeeb yuav tsum tau ua raws li nruj me ntsis, suav nrog hnav lub npog ntsej muag roj, tsom iav tiv thaiv, cov hnab looj tes acid- thiab alkali-resistant roj hmab, thiab cov khaub ncaws ua haujlwm acid-resistant.

1. Kev sib cuag ntawm daim tawv nqaij: Tshem cov khaub ncaws tsis huv thiab ntxuav daim tawv nqaij nrog dej txaus.
2. Kev sib cuag qhov muag: Tam sim ntawd rub daim tawv muag thiab yaug nrog dej los yog ntsev rau yam tsawg 15 feeb; nrhiav kev kho mob.
3. Inhalation: Txav mus rau huab cua ntshiab thiab xyuas kom lub ntsws tsis muaj kev cuam tshuam. Yog tias ua pa nyuaj, muab cov pa oxygen; yog tias ua tsis taus pa, ua pa ua pa thiab nrhiav kev kho mob.
4. Noj: Haus dej sov kom ntau, ua kom ntuav, thiab nrhiav kev kho mob.
5. Txoj kev tua hluav taws: Siv dej, pos huab, hmoov qhuav, lossis xuab zeb los tua hluav taws. Nyob rau hauv rooj plaub ntawm cov dej xau, tshem cov neeg ua haujlwm mus rau qhov chaw nyab xeeb.

3.4 Inorganic Alkali

Hauv kev tsim cov txheej txheem ntawm polycarboxylate superplasticizers, inorganic alkalis feem ntau yog siv los nruab nrab cov tshuaj tiv thaiv thiab txiav nws. Feem ntau siv inorganic alkali yog sodium hydroxide. Khoom flake sodium hydroxide, feem ntau hu ua caustic soda, yog cov khoom siv alkaline ntau tshaj plaws hauv kev lag luam carboxylic acid.

Caustic soda yog tsis-flammable, tab sis nws tso tawm ntau lub tshav kub thaum nws los rau hauv kev sib cuag nrog dej los yog dej vapor, tsim ib tug corrosive tov. Nws reacts nrog acids, tso cua sov. Nws yog heev corrosive thiab muaj zog irritating. Nws cov plua plav lossis pa taws tuaj yeem ua rau lub qhov muag thiab ua pa ua pa, ua rau lub qhov ntswg septum, thiab ua rau kub hnyiab thaum sib cuag nrog daim tawv nqaij thiab qhov muag. Kev noj tshuaj tsis haum tuaj yeem ua rau kub hnyiab hauv plab hnyuv, mucosal yaig, los ntshav, thiab poob siab.

Cov neeg ua haujlwm yuav tsum hnav khaub ncaws tiv thaiv, hnab looj tes, tsom iav, lossis qhov ncauj qhov ntswg ua ntej pib ua haujlwm. Lub Hoobkas yuav tsum muaj kev nyab xeeb da dej thiab qhov muag ntxuav. Yog hais tias nws nkag mus rau hauv lub qhov muag, yaug tam sim ntawd nrog dej los yog saline rau 15 feeb, ces thov 2% novocaine. Thaum mob hnyav, nrhiav kev kho mob.