RDP Kev Tso Kho thiab Kev Qhuas Ntawv: Tswi tsis cov lwm thiab tswi tsis qhov sib xws

Ua paub txog kev qhuas ntawv RDP tshwj xeeb

Kev qhuas ntawv thiab nws kev puas qhia rau kev qhuas ntawv zoo

Cov txoj hauv kev uas cov khoom tshuaj polymer (RDP) yuav qhia cov dej yog qhov tseem ceeb rau kev sib tw ntawm kev qhia cov khoom. Yog tias kev qhia dej yog li ntev, nws yuav ua rau cov ntaub ntawv hauv qab nkaus los ntawm cov dej thiab ua rau muaj qhov khaub ncua uas tsis pub cov ntaub ntawv polymer uas tsis tau qhia dej nyob hauv qab. Rau kev ua tau zoo tshaj plaws, cov ntaub ntawv uas muaj qhov loj ntawm 20 microns lossis ntev dua yog raug los siv thaum siv cov dej uas tau muab sib tshuam kom muaj qhov rov qhia, thiab yuav tsum muaj qhov siab ntawm 5 degrees Celsius mus rau 40 degrees Celsius. Qhov no yuav pab cov polymer chains kom rov qhia cov ntaub ntawv tau zoo. Tsis tas li ntawd, yog tias kev qhia dej yog li ntev dua 90 seconds, nws yuav muaj qhov zoo: cov ntaub ntawv uas tsis tau qhia dej yuav ntev dua li 60% vim tias muaj kev qhia dej raws li qhov tseem ceeb. Qhov no yuav pab tshem tawm cov "fish eyes" uas peb pom nyob rau hauv kev siv cement, uas yog cov ntaub ntawv uas tsis tau qhia dej zoo thiab yuav pab tshem tawm cov kev nyab xeeb ntawm kev siv cement.

Yus li cas uas kev ua ntaub ntawv tshiab ua ntej thaum lub cim no yog qhov tseem ceeb—tab sis tsis yog txhua yam

Kuam soj RDP hauv ethanol lossis plasticizers yuav pab txhawj qhia cov ntsiab lus uas tsis muaj ntaub ntawv nyob rau hauv dej, vim tias nws yuav pab txhawj qhia cov kev tshuaj ntsuas ntawm cov ntsiab lus sib txawv, thiab nws yuav pab txhawj qhia cov teeb meem uas cov ntsiab lus ua ke. Qhov kev pab tshuaj ntsuas no yog qhov txaus siab heev thaum siv cov polymer loj uas muaj viscosity zoo li 50,000 mPa·s, cov powder cuj uas tau npaj lawm ntev dua lwm hnub rau 6 lub hlis thiab muaj dej nyob hauv nws ntev dua 0.8%, thiab thaum muaj qhov kev tshuaj ntsuas tsis loj rau hauv qhov kev sib npaj. Qhov zoo tshaj plaws yog tias cov technology pab kuam tshuaj ntsuas tshiab yuav pab cov powder no kuam tshuaj ntsuas raws li ntawd hauv cov alkaline solutions uas muaj pH zoo li 12 los sis dua, thiab cov salt concentration zoo li no yuav pab txhawj qhia cov particles tshuaj ntsuas ntev dua. Cov RDP uas tau kuam tshuaj ntsuas hauv qhov freezing yuav pab txhawj qhia cov structure uas muaj qhov tshuaj ntsuas zoo li no, thiab cov no yuav pab txhawj qhia cov dispersion rates zoo li 98% tsis xav tau kev pab tshuaj ntsuas ntxiv. Qhov no qhia tias tsis muaj kev pab tshuaj ntsuas ib yam uas tuaj yeem siv rau txhua yam, vim tias kev pab tshuaj ntsuas yuav tsum sib thag nrog cov formula uas peb siv thiab nws yuav siv rau qhov twg.

Tshuaj xyuam rau RDP khoob tshuaj kom zoo los ntawm kev tswj hwm qhov kev txuas dua

Khoob tshuaj zoo ntawm Redispersible Polymer Powder (RDP) yog qhov tseem ceeb rau kev txuas dua zoo thiab sib tw. Yog tias khoob tshuaj tsis zoo, nws yuav pab cuam rau kev puas tsuaj ntawm cov khoom tshuaj, uas ua rau cov khoom tshuaj muaj kev puas tsuaj thiab tsis tuaj yeem txuas dua tau, thiab ua rau tsis tuaj yeem siv tau hauv qhov siv nyob rau thaum kawg.

Kev tswj hwm qhov dej, kev tswj hwm qhov khoob tshuaj, thiab qhov sijhawm uas tuaj yeem siv tau

Kuam ntsuas ntawm cov dej hauv qhov no yuav tsum tsis txog 0.5% yog qhov tseem ceeb heev rau qhov uas peb xav tshem tawm qhov kev ua cov ntaub ntawv tshiab uas muaj nyob hauv qhov kev sib sau ntawm cov ntaub ntawv. Qhov kev tswj hwm ntawm qhov stability no tau raug qhia tias yog qhov tseeb los ntawm kev kho mob uas tau pub tseg los ntawm Journal of Coatings Technology nyob rau hauv xyoo 2023. Rau qhov kev kuaj xyuas, cov khoom uas muaj cov kab laug uas muaj cov ntaub ntawv aluminum uas muaj ntau daim thiab tau khawv tshwj xeeb yog qhov tseem ceeb heev rau qhov uas tshem tawm qhov dej ntawm lub ciaj ntawm qhov ntim. Qhov no yuav tshwj xeeb dua li thaum peb siv cov khoom uas tau ntim rau hauv qhov chaw uas muaj dej thiab ntev, xws li qhov chaw tropic uas lub ciaj tuaj yeem muaj dej ntau dua 80%. Qhov sijhawm uas cov ntaub ntawv no yuav nyob tau yuav nyob ntawm qhov ntaub ntawv polymer uas muaj hauv no. Cov ntaub ntawv vinyl acetate ethylene copolymers yuav tso cia tau zoo rau qhov kev sib sau dua rau nyob ib puag ncig 12 hlis thaum muaj qhov ciaj ntawm 25 degrees Celsius thiab 60% relative humidity. Thaum muaj los ntawm qhov sijhawm no, qhov kev lag luam yuav pib nce siab uas yuav pab cuam rau qhov kev sib sau tsis zoo thiab yuav pab cuam rau qhov kev ua cov mortar strength tsis zoo thaum siv.

Yam li cas uas kev hloov ntawm qhov ceev yuav cuam tshuam rau lub zog ntawm cov khoom tawg

Thaum qhov ceev txuas ntau dua 35 degrees Celsius, qhov uas los ntawm kev hloov ntawm cov khoom tawg (plasticizer migration) yuav pib dhau. Qhov no ua rau muaj cov ntawv hauv qhov chaw uas tsis nyob ib leeg rau dej, thiab ua rau cov khoom tsis tau txais dej raws li yuav tsum tau. Cov kev sim hauv tsev sim (lab) uas qhov ceev hloov ntawm 15 thiab 40 degrees Celsius yog qhov sib thag rau qhov ceev hloov hauv cov tsev kho khoom hauv qhov xyoj. Cov kev sim no xwb tias cov ntawv tsaus rau cov khoom tawg yuav hloov ntau dua 18 percent thaum muaj qhov ceev hloov. Qhov uas puas lawm yuav tshwm ntau dua thiab yuav tshwm ntau dua thiab yuav tshwm ntau dua. Qhov hloov ntawm cov ntawv yuav ua rau kev tswb cov khoom tawg yuav tsum siv ntau dua. Thaum siv cov khoom tswb uas muaj qhov siab thiab siv ntau dua, qhov ua rau cov khoom tawg tshwm ntau dua yuav tshwm ntau dua 40 percent ntau dua thaum qhov ceev tsis hloov.

Tsim cov xwm txheej uas nyob hauv 30°C thiab nyob ib txwm yog qhov tseem ceeb rau kev tswj qhov polymer’s glass transition temperature (Tg), uas pab tshem tsoom rau kev nkag mus rau hauv dej raws li kev tswj lub cev.

Tsim cov lus uas tsis tuaj yeem rov qab thaum rehydrating RDP

Nucleation-Driven Agglomeration nyob rau hauv qhov chaw dej—powder interface

Thaum RDP tau sib sau rau ntaub ntawv, nws yuav tshwm sim qhov kawm ntawv hauv qab ntsuas rau hauv qab ntsuas, ua rau muaj cov chaw uas muaj kev nyuaj siab thiab yog qhov cim rau cov ntawv los daws tawm mus rau lawv ib zaj. Qhov no yuav tshwm sim raws li qhov kev ua cov ntawv tshiab. Cov kab mob leej twg yuav tshwm sim ua rau cov ntawv tsis muaj kev nyuaj siab los ntawm kev nyuaj siab thiab kev nyuaj siab ntawm hydrogen, thiab yuav tshwm sim ua rau muaj cov kab mob loj dua li 5 cm. Cov kab mob no yuav tshwm sim ua rau muaj kev nyuaj siab rau kev daws tawm, thiab yuav tshwm sim ua rau muaj kev nyuaj siab rau kev daws tawm hauv qhov kev siv rau cov ntawv. Yog tias tsis muaj kev daws tawm, cov kab mob no yuav tshwm sim ua rau muaj kev nyuaj siab rau kev daws tawm hauv qhov kev siv rau cov ntawv.

Qhov kev siv kev nyuaj siab rau kev daws tawm cov kab mob thaum kawg

Kev sib thaj ntau hauv qhov sijhawm tseem ceeb ntawm 60 feeb thaum kawg tom qab sau dej rau hauv yuav ua rau cov chaw uas pom hauv qhov kawg thiab tsis tau ua cov cuab yeej uas muaj kev nyab xeeb. Lub tshuab tswv yim coob tuaj siab tias tswv yim ntawm kev sib thaj ntawm 500 rau 1500 rpm yuav ua rau cov khoom sib txuas nrog ib leeg raws li xav tau. Thaum sib thaj cov khoom uas muaj qhov zoo li dej thiab yuav tshwm sim rau kev sib thaj, cov neeg tsim khoom coob tuaj sib thaj RDP nrog cov khoom uas muaj qhov zoo li silica sand thaum kawg. Qhov kev sib thaj no yuav ua rau qhov ntsiab ntawm cov khoom tsis tau sib thaj nrog dej ntev dua. Dej yeeb yuav zoo dua. Tso cov khoom hauv qhov ntsiab uas tsis pheej 25 degrees Celsius yuav pab tshem tawm cov khoom uas muaj qhov zoo li dej thiab tsis tau ua rau cov polymer chains sib tshuas nrog ib leeg. Qhov tseem ceeb yog kev nrhiav qhov zoo tshaj plaws ntawm kev sib thaj. Yog tias muaj kev sib thaj ntau, nws yuav ua rau muaj dej ntxiv hauv cov khoom; tab sis yog tias muaj kev sib thaj tsawg, nws yuav tshem tawm cov khoom uas tsis tau sib thaj kom zoo thiab yuav ua rau muaj teeb meem ntau dua tom ntej.

Tshem tawm kev sib thaj ntawm cov khoom RDP

Kuam paub txog kev txiav txim siab tias yuav tau txais cov lus teb zoo tib yam los ntawm kev siv RDP tsis tuaj yeem nyob rau hauv kev kawm tshwj xeeb rau peb qhov chaw sib piv: cov khoom siv rau hauv qhov tseeb, kev siv dej rau hauv qhov tseeb, thiab kev ua kom paub tias peb kev ua haujlwm yog zoo. Qhov kawg ntawm qhov tseeb yog ua raws li cov polymer resins uas muaj kev tswj hwm, thiab ua raws li cov ratios ntawm cov colloid uas pab tshem tawm. Yog tias muaj kev sib txawv ntawm cov particle size distribution ntau dua 2%, ces qhov risk ntawm kev sib sau ntau dua 40% raws li cov kev kawm txog powder flow uas peb tau pom. Ntawd yog qhov tias nws yog qhov tseem ceeb heev. Peb kuj yuav tsum xyuam xyuam rau qhov moisture level thaum peb khoov cov khoom. Yog tias qhov humidity ntau dua 0.5%, ces nws yuav pab cuam kev ua film ntxiv lawm uas tsis muaj leej twg xav tau. Thiab thaum peb yuav tsum siv dej rau hauv qhov tseeb, muaj ntau yam uas peb yuav tsum xyuam xyuam rau...

• Tso cia qhov dej muaj qhov teb ntsuas hauv ±2°C ntawm qhov Tg ntawm cov polymer
• Siv kev tshuaj ntxiv uas muaj qhov tshuaj ntxiv 800–1200 rpm rau 90 seconds thaum lub sijhawm uas siv cov powder
• Tshawb xyuas kev ntsuas qhov cua tsoo ntawm cov khoom siv los ntawm kev siv lub tshuab tswv yim kawg ua ntej txhawb cov khoom

Kev tshawb xyuas rau peb qhov tswv yim sib txawv thiab kev siv kev tshawb xyuas kev tsim kho (SPC) tuaj yeem pab paub txog cov teeb meem ua ntej thaum lawv tau dhau los rau qhov nyuaj heev. Cov tswv yim no puav leej yog: qhov pH hloov, qhov xwm txheej uas cov khoom yuav tsum rov qab mus rau hauv cov dej, thiab kev tshawb xyuas qhov ntxiv ntau ntawm cov khoom siv. Cov phab ntsa uas siv cov kev tshawb xyuas qhov tswv yim los ntawm qhov tswv yim rau qhov tswv yim no yuav muaj zaus 98% ntawm cov khoom uas tau txais qhov tswv yim, uas pab txo cov teeb meem hauv qhov tom qab uas peb tau paub zoo – piv txwv li: cov mortar uas muaj qhov tshuab lossis cov tile uas tsis tuaj yeem tsw ncaj ncaj. Thaum cov khoom siv tau tsw ncaj ncaj rau hauv qhov tsim kho, nws yuav ua rau cov polymer film uas muaj qhov tsw ncaj ncaj uas cov neeg tsim kho tau paub zoo tias yog qhov tswv yim rau cov khoom siv kom yuav nyuaj dua thiab tsis tau tshuab ua ntej thaum yuav nyuaj.

Lus nug tswv yim txog RDP rehydration

Qhov xwm txheej ntsuas qhov cua tsoo twg yog qhov zoo tshaj plaws rau RDP rehydration?

Qhov qhib ntawm cov cim tshuaj uas yuav tsum tau siv rau kev txuas dua RDP yog ntawm 5 degrees Celsius thiab 40 degrees Celsius. Thib ob qhov no pab tshem tau tias cov polymer chains yuav tsum txuas dua raws li txoj kev tseeb.

Puas yog kev ntxuav ntxiv yog qhov tseem ceeb rau RDP?

Kev ntxuav ntxiv nrog cov khoom zoo li ethanol lossis cov plasticizers pab txhawm rau txhawm rau tshem cov lwm tshuaj uas muaj qhov ntsuas tsis zoo, uas yog qhov tseem ceeb rau cov polymer zoo li qhov loj thiab cov lwm tshuaj uas muaj qhov ntsuas tsis zoo li qhov ntsuas ntau dua.

RDP yuav tsum tau sau ua kom zoo rau hantag puas li?

RDP yuav tsum tau sau ua kom zoo rau hantag 12 hlis thaum sau ua kom zoo rau hantag 25 degrees Celsius thiab 60% relative humidity. Thaum mus los ntawm qhov no, cov kev lag luam yuav tshwm sim ntau dua, uas yuav pab tshem tau kev ua haujlwm.

Cov kev hloov qhov cim tshuaj yuav tshwm sim li cas rau RDP?

Cov kev hloov qhov cim tshuaj, tshwj xeeb tias thaum hloov qhov cim tshuaj ntau dua 35 degrees Celsius, yuav pab tshem tau qhov ntsuas ntawm cov particles, uas pab tshem tau kev txuas dua thiab pab tshem tau kev siv hluav taws xob thaum txuas.

Koj yuav tsum ua li cas rau tshem tau cov lwm tshuaj thaum txuas dua RDP?

Thiab kom tsis muaj qhov tshuaj ntsuas, siv kev kho tshuaj ntsuas uas muaj qhov siab rau 60 feeb thaum kawg ntawm qhov ntaus ntawm dej thiab tso cia qhov hluav tais tsev yooj dua kom tsis tau txais qhov tshuaj ntsuas los ntawm qhov tshuaj ntsuas. Qhov kev kho tshuaj ntsuas zoo yog qhov tseem ceeb rau kom paub txog qhov tshuaj ntsuas uas muaj nyob hauv qhov kawg.