Nonionic cellulose ether a cikin siminti polymer

A matsayin ƙari mai mahimmanci a cikin simintin polymer, nonionic cellulose ether ya sami kulawa mai yawa da bincike. Dangane da wallafe-wallafen da suka dace a gida da kuma waje, an tattauna doka da tsarin da ba na ionic cellulose ether gyare-gyaren turmi na ciminti daga sassa na nau'o'in da zaɓi na ether wanda ba na ionic cellulose ba, tasirinsa akan kaddarorin jiki na ciminti polymer, tasirinsa akan micromorphology da kaddarorin injiniya, kuma an gabatar da gazawar binciken da ake yi yanzu. Wannan aikin zai inganta aikace-aikacen ether cellulose a cikin simintin polymer.

Mabuɗin kalmomi: nonionic cellulose ether, polymer ciminti, jiki Properties, inji Properties, microstructure

1. Bayani

Tare da karuwar buƙatu da buƙatun aikin simintin polymer a cikin masana'antar gine-gine, ƙara abubuwan haɓakawa zuwa gyare-gyarensa ya zama wurin bincike, daga cikinsu, ether cellulose an yi amfani da shi sosai saboda tasirin sa akan ciminti turmi ruwa, kauri, retarding, iska. da sauransu. A cikin wannan takarda, an kwatanta nau'ikan ether na cellulose, abubuwan da ke tattare da kayan aikin jiki da na injiniya na simintin polymer da micromorphology na ciminti polymer, wanda ke ba da ma'anar ka'idar aikace-aikacen ether na cellulose a cikin ciminti na polymer.

2. Nau'in nonionic cellulose ether

Cellulose ether wani nau'i ne na fili na polymer tare da tsarin ether wanda aka yi daga cellulose. Akwai nau'ikan ether na cellulose da yawa, wanda ke da babban tasiri a kan kaddarorin kayan da ke da siminti kuma yana da wuya a zaɓa. Bisa ga tsarin sinadarai na maye gurbin, ana iya raba su zuwa anionic, cationic da nonionic ethers. Nonionic cellulose ether tare da gefen sarkar maye gurbin na H, cH3, c2H5, (cH2cH20) nH, [cH2cH (cH3) 0] nH da sauran wadanda ba dissociable kungiyoyin ne mafi yadu amfani da sumunti, hankula wakilan su ne methyl cellulose ether, hydroxypropyl methyl. cellulose ether, hydroxyethyl methyl cellulose ether, hydroxyethyl cellulose ether da sauransu. Daban-daban nau'ikan ethers cellulose suna da tasiri daban-daban akan saita lokacin siminti. Bisa ga rahotannin wallafe-wallafen da suka gabata, HEC yana da ƙarfin jinkirta ciminti, wanda HPMc da HEMc suka biyo baya, kuma Mc yana da mafi muni. Ga irin wannan nau'in cellulose ether, kwayoyin nauyi ko danko, methyl, hydroxyethyl, hydroxypropyl abun ciki na wadannan kungiyoyin ne daban-daban, ta retarding sakamako ma daban-daban. Gabaɗaya magana, mafi girman danko kuma mafi girman abun ciki na ƙungiyoyin da ba za a raba su ba, mafi munin iyawar jinkiri. Sabili da haka, a cikin ainihin tsari na samarwa, bisa ga bukatun kasuwancin turmi coagulation, za a iya zaɓar abun ciki na ƙungiyar da ya dace na ether cellulose. Ko kuma a cikin samar da ether cellulose a lokaci guda, daidaita abubuwan da ke cikin ƙungiyoyi masu aiki, sa ya dace da bukatun daban-daban turmi.

3,tasiri na nonionic cellulose ether a kan kayan jiki na simintin polymer

3.1 Sannu a hankali coagulation

Domin tsawaita lokacin hardening hydration na ciminti, sabõda haka, sabon gauraye turmi a cikin dogon lokaci ya zama filastik, don daidaita saitin lokaci na sabon gauraye turmi, inganta ta operability, yawanci ƙara retarder a turmi, ba- ionic cellulose ether dace da polymer ciminti ne na kowa retarder.

Sakamakon retarding na nonionic cellulose ether a kan ciminti ya fi shafar nau'in kansa, danko, sashi, daban-daban abun da ke ciki na ma'adinan ciminti da sauran dalilai. Pourchez J et al. ya nuna cewa mafi girma matakin cellulose ether methylation, mafi muni da retarding sakamako, yayin da kwayoyin nauyi na cellulose ether da hydroxypropoxy abun ciki yana da rauni tasiri a kan retarding na ciminti hydration. Tare da karuwa da danko da doping adadin wadanda ba ionic cellulose ether, adsorption Layer a kan saman simintin barbashi ne thickened, da farko da na karshe saitin lokaci na ciminti an kara tsawo, da kuma retarding sakamako ne mafi bayyane. Nazarin ya nuna cewa farkon zafin da aka saki na siminti tare da abun ciki na HEMC daban-daban yana da kusan 15% ƙasa da na siminti mai tsabta, amma babu wani bambanci mai mahimmanci a cikin tsarin samar da ruwa na baya. Singh NK et al. ya nuna cewa tare da karuwar adadin HEc doping, hydration zafi saki na gyare-gyaren turmi siminti ya nuna yanayin karuwa na farko sannan kuma raguwa, kuma abun ciki na HEC lokacin da ya kai matsakaicin matsakaicin zafi na hydration yana da alaƙa da shekarun warkewa.

Bugu da ƙari, an gano cewa sakamakon retarding na nonionic cellulose ether yana da alaƙa da haɗin gwiwar siminti. Peschard et al. gano cewa ƙananan abun ciki na tricalcium aluminate (C3A) a cikin siminti, mafi bayyananniyar tasirin ether na cellulose. Schmitz L et al. yi imani da cewa wannan ya faru ta hanyoyi daban-daban na cellulose ether zuwa hydration kinetics na tricalcium silicate (C3S) da tricalcium aluminate (C3A). Cellulose ether zai iya rage yawan amsawa a cikin lokacin haɓakawa na C3S, yayin da C3A, zai iya tsawaita lokacin ƙaddamarwa, kuma a ƙarshe jinkirta tsarin ƙarfafawa da taurin turmi.

Akwai ra'ayoyi daban-daban game da tsarin da ba ionic cellulose ether jinkirta ciminti hydration. Silva et al. Liu ya yi imanin cewa shigar da ether na cellulose zai haifar da dankowar maganin pore ya karu, don haka ya toshe motsi na ions da jinkirta damfara. Koyaya, Pourchez et al. yi imani da cewa akwai wata alaƙa da ke tsakanin jinkirin ether cellulose zuwa ciminti hydration da danko na siminti slurry. Wata ka'idar ita ce cewa sakamakon retarding na cellulose ether yana da alaƙa da lalata alkali. Polysaccharides yakan ƙasƙanci sauƙi don samar da hydroxyl carboxylic acid wanda zai iya jinkirta hydration na siminti a ƙarƙashin yanayin alkaline. Duk da haka, binciken ya gano cewa ether cellulose yana da kwanciyar hankali a ƙarƙashin yanayin alkaline kuma kawai ya rage kadan, kuma raguwa yana da tasiri kadan akan jinkirta ciminti hydration. A halin yanzu, mafi daidaiton ra'ayi shine cewa tasirin retarding yafi faruwa ta hanyar tallatawa. Musamman, ƙungiyar hydroxyl a kan kwayoyin halitta na cellulose ether shine acidic, ca (0H) a cikin tsarin simintin hydration, da sauran matakan ma'adinai sune alkaline. A ƙarƙashin aikin haɗin gwiwar haɗin gwiwar hydrogen, hadaddun abubuwa da hydrophobic, kwayoyin acidic cellulose ether za a tallata su a saman sassan siminti na alkaline da samfuran hydration. Bugu da kari, an samar da wani siriri fim a samansa, wanda ke hana ci gaban ci gaban wadannan ma'adinai lokaci crystal nuclei da jinkirta hydration da saitin siminti. Ƙarfin ƙarfin adsorption tsakanin samfuran hydration na siminti da ether cellulose, mafi mahimmancin jinkirin hydration na siminti. A gefe guda, girman ƙwanƙwasa ƙwanƙwasa yana taka muhimmiyar rawa a cikin ƙarfin adsorption, irin su ƙananan ƙwanƙwasawa na ƙungiyar hydroxyl, ƙaƙƙarfan acidity, adsorption kuma yana da ƙarfi. A daya hannun, da adsorption iya aiki kuma ya dogara da abun da ke ciki na hydration kayayyakin na siminti. Pourchez et al. An gano cewa ether cellulose yana da sauƙi a sauƙaƙe zuwa saman samfuran hydration irin su ca (0H) 2, csH gel da calcium aluminate hydrate, amma ba shi da sauƙi a yi amfani da shi ta hanyar ettringite da lokacin rashin ruwa. Har ila yau, binciken Mullert ya nuna cewa ether cellulose yana da tasiri mai karfi akan c3s da kayan aikin sa na ruwa, don haka hydration na silicate lokaci ya jinkirta sosai. Adsorption na ettringite ya yi ƙasa kaɗan, amma samuwar ettringite ya yi jinkiri sosai. Wannan shi ne saboda jinkirin samuwar ettringite ya shafi ca2 + ma'auni a cikin bayani, wanda shine ci gaba da jinkirin ether cellulose a cikin silicate hydration.

3.2 Tsarewar Ruwa

Wani muhimmin tasiri na gyare-gyare na cellulose ether a cikin turmi siminti shine bayyana a matsayin wakili mai riƙe da ruwa, wanda zai iya hana danshi a cikin rigar turmi daga evaporating da wuri ko kuma a shayar da shi ta tushe, kuma yana jinkirta hydration na siminti yayin da yake tsawaita lokacin aiki. jika turmi, don tabbatar da cewa za a iya tsefe siraran turmi, za a iya yada turmi mai laushi, kuma mai sauƙin tsotse turmi baya buƙatar rigar rigar.

Ƙarfin riƙon ruwa na ether cellulose yana da alaƙa da ɗanko, sashi, nau'in da zafin jiki na yanayi. Sauran yanayi iri ɗaya ne, mafi girman danko na ether cellulose, mafi kyawun sakamako na riƙewar ruwa, ƙaramin adadin ether na cellulose zai iya sa yawan adadin ruwa na turmi ya inganta sosai; Don ether cellulose guda ɗaya, mafi girman adadin da aka ƙara, mafi girman adadin ajiyar ruwa na turmi da aka gyara, amma akwai darajar mafi kyau, bayan abin da adadin ruwa ya karu a hankali. Ga nau'ikan ether na cellulose daban-daban, akwai kuma bambance-bambance a cikin riƙe ruwa, kamar HPMc a ƙarƙashin yanayi iri ɗaya fiye da Mc mafi kyawun riƙe ruwa. Bugu da ƙari, aikin riƙewar ruwa na ether cellulose yana raguwa tare da karuwar zafin jiki.

An yi imani da cewa dalilin da ya sa cellulose ether yana da aikin riƙe ruwa shine yafi saboda 0H akan kwayoyin halitta kuma 0 atom akan ether bond za a hade shi da kwayoyin ruwa don hada haɗin hydrogen, ta yadda ruwan kyauta ya zama mai ɗaure. ruwa, ta yadda za a taka rawa mai kyau na rike ruwa; Haka kuma an yi imani da cewa cellulose ether macromolecular sarkar taka taka rawa a cikin watsar da ruwa kwayoyin, ta yadda yadda ya kamata sarrafa ruwa evaporation, don cimma high ruwa riƙewa; Pourchez J ya bayar da hujjar cewa ether cellulose ya sami tasirin riƙewar ruwa ta hanyar inganta rheological Properties na sabon gauraye siminti slurry, tsarin porous cibiyar sadarwa da samuwar cellulose ether fim wanda ya hana yaduwar ruwa. Laetitia P et al. Har ila yau, yi imani da cewa rheological dukiya na turmi ne key factor, amma kuma yi imani da cewa danko ne ba kawai factor kayyade kyau kwarai riƙon ruwa yi na turmi. Shi ne ya kamata a lura da cewa ko da yake cellulose ether yana da kyau ruwa rike yi, amma ta modified taurare ciminti turmi ruwa sha za a rage, dalilin shi ne cewa cellulose ether a cikin turmi film, kuma a cikin turmi babban adadin kananan rufaffiyar pores, tarewa. turmi a cikin capillary.

3.3 Kauri

Daidaiton turmi ɗaya ne daga cikin mahimman bayanai don auna aikin sa. Ana gabatar da ether cellulose sau da yawa don ƙara daidaito. “Daidaitawa” yana wakiltar ikon sabon turmi mai gauraya don gudana da lalacewa ƙarƙashin aikin ƙarfi ko ƙarfin waje. Abubuwan biyu na kauri da riƙewar ruwa suna haɗa juna. Ƙara adadin da ya dace na ether cellulose ba zai iya kawai inganta aikin riƙe ruwa na turmi ba, tabbatar da gina jiki mai santsi, amma kuma ƙara daidaituwa na turmi, ƙara haɓaka ƙarfin siminti, haɓaka aikin haɗin gwiwa tsakanin turmi da matrix, kuma rage ɓacin rai na turmi.

A thickening sakamako na cellulose ether yafi fitowa daga nasa danko, mafi girma danko, mafi kyau da thickening sakamako, amma idan danko ya yi yawa girma, zai rage fluidity na turmi, shafi ginin. Abubuwan da ke shafar canjin danko, irin su nauyin kwayoyin halitta (ko digiri na polymerization) da kuma maida hankali na ether cellulose, zafin bayani, ƙimar ƙarfi, zai shafi sakamako mai girma na ƙarshe.

Tsarin kauri na ether cellulose ya fito ne daga hydration da ƙullawa tsakanin kwayoyin halitta. A gefe guda, sarkar polymer na cellulose ether yana da sauƙi don samar da haɗin hydrogen tare da ruwa a cikin ruwa, haɗin hydrogen ya sa ya sami babban hydration; A daya bangaren kuma, lokacin da aka hada ether cellulose a cikin turmi, zai sha ruwa mai yawa, ta yadda girmansa ya kara fadada sosai, yana rage sararin sarari na barbashi, a lokaci guda kuma sassan kwayoyin ether na cellulose suna haɗuwa da juna. don samar da tsarin cibiyar sadarwa mai girma uku, ƙwayoyin turmi suna kewaye da su, ba kyauta ba. A wasu kalmomi, a ƙarƙashin waɗannan ayyuka guda biyu, an inganta danko na tsarin, don haka samun sakamako mai girma da ake so.

4. Tasirin nonionic cellulose ether akan ilimin halittar jiki da tsarin pore na ciminti polymer.

Kamar yadda ake iya gani daga sama, ether maras ionic cellulose yana taka muhimmiyar rawa a cikin simintin polymer, kuma ƙari da shi tabbas zai shafi ƙananan ƙananan ƙwayoyin simintin gaba ɗaya. Sakamakon ya nuna cewa ba-ionic cellulose ether yawanci ƙara porosity na siminti turmi, da kuma yawan pores a cikin girman 3nm ~ 350um yana ƙaruwa, daga cikinsu akwai adadin pores a cikin kewayon 100nm ~ 500nm yana ƙaruwa. Tasiri akan tsarin pore na turmi siminti yana da alaƙa da alaƙa da nau'in da danko na ether maras ionic cellulose. Ou Zhihua et al. yi imani da cewa lokacin da danko ne iri ɗaya, porosity na siminti turmi gyara ta HEC ne karami fiye da na HPMc da Mc kara a matsayin gyare-gyare. Don ether ɗin cellulose guda ɗaya, ƙarami da danko, ƙaramin porosity na turmi siminti da aka gyara. Ta hanyar nazarin tasirin HPMc akan buɗaɗɗen kumfa mai rufin siminti, Wang Yanru et al. gano cewa ƙari na HPMC ba ya canza porosity sosai, amma yana iya rage yawan buɗewar. Koyaya, Zhang Guodian et al. gano cewa mafi girman abun ciki na HEMc, mafi mahimmancin tasiri akan tsarin pore na siminti slurry. Bugu da ƙari na HEMc na iya ƙara yawan porosity, jimlar pore da matsakaicin radius na ciminti slurry, amma ƙayyadaddun yanki na pore yana raguwa, kuma adadin manyan pores na capillary ya fi girma fiye da 50nm a diamita yana ƙaruwa sosai, kuma pores da aka gabatar. sun fi rufe pores.

An yi nazarin tasirin nonionic cellulose ether akan tsarin samar da siminti slurry pore tsarin. An gano cewa ƙari na ether cellulose yafi canza kaddarorin lokaci na ruwa. A gefe guda, tashin hankali na lokacin ruwa yana raguwa, yana sauƙaƙa samar da kumfa a cikin turmi siminti, kuma zai rage saurin magudanar ruwa da yaduwar kumfa, ta yadda ƙananan kumfa suna da wahalar tattarawa cikin manyan kumfa da fitarwa, don haka ɓarna. yana ƙaruwa sosai; A daya hannun, danko na ruwa lokaci yana ƙaruwa, wanda kuma ya hana magudanar ruwa, kumfa kumfa da haɗuwa da kumfa, kuma yana haɓaka ikon daidaita kumfa. Sabili da haka, ana iya samun tasirin yanayin cellulose ether akan girman girman girman rarraba siminti: a cikin kewayon girman girman fiye da 100nm, ana iya gabatar da kumfa ta hanyar rage tashin hankali na lokaci na ruwa, kuma ana iya hana yaduwar kumfa. ƙara yawan danko; a cikin yanki na 30nm ~ 60nm, adadin pores a cikin yankin zai iya tasiri ta hanyar hana haɗuwa da ƙananan kumfa.

5. Tasirin nonionic cellulose ether akan kayan aikin injiniya na simintin polymer

Abubuwan injiniya na simintin polymer suna da alaƙa da alaƙa da ilimin halittar jiki. Tare da ƙari na nonionic cellulose ether, porosity yana ƙaruwa, wanda ke daure ya yi mummunan tasiri a kan ƙarfinsa, musamman ma ƙarfin matsawa da ƙarfin sassauci. Rage ƙarfin matsawa na turmi siminti yana da mahimmanci fiye da ƙarfin sassauƙa. Ou Zhihua et al. yayi nazarin tasirin nau'ikan nau'ikan nau'ikan cellulose da ba na ionic ba akan kayan injin siminti, kuma ya gano cewa ƙarfin cellulose ether wanda aka gyara turmi siminti ya yi ƙasa da na turmi siminti mai tsafta, kuma mafi ƙarancin 28d ƙarfin matsawa shine kawai 44.3% na tsaftataccen siminti slurry. Ƙarfin matsawa da ƙarfin motsi na HPMc, HEMC da MC cellulose ether gyare-gyare suna kama da haka, yayin da ƙarfin matsawa da ƙarfin ƙarfi na HEc wanda aka gyara siminti slurry a kowane zamani yana da mahimmanci mafi girma. Wannan yana da alaƙa ta kusa da danko ko nauyin kwayoyin halitta, mafi girman danko ko nauyin kwayoyin halitta na cellulose ether, ko mafi girman aikin saman, ƙananan ƙarfin turmi siminti da aka gyara.

Duk da haka, an kuma nuna cewa nonionic cellulose ether na iya haɓaka ƙarfin ƙarfi, sassauci da haɗin kai na simintin siminti. Huang Liangen et al. ya gano cewa, sabanin dokar canji na ƙarfin matsawa, ƙarfin ƙarfi da ƙarfi na slurry ya karu tare da karuwar abun ciki na ether cellulose a cikin turmi siminti. Analysis na dalilin, bayan Bugu da kari na cellulose ether, da kuma polymer emulsion tare da samar da wani babban adadin m polymer film, ƙwarai inganta sassauci na slurry, da kuma ciminti hydration kayayyakin, unhydrated ciminti, fillers da sauran kayan cika a cikin wannan fim. , don tabbatar da ƙarfin ƙarfi na tsarin sutura.

Domin inganta aikin da ba ionic cellulose ether modified polymer ciminti, inganta jiki Properties na ciminti turmi a lokaci guda, ba ya rage muhimmanci da inji Properties, da saba yi shi ne daidaita cellulose ether da sauran admixtures, kara da cewa. turmi siminti. Li Tao-wen et al. gano cewa hadadden ƙari hada da cellulose ether da polymer manne foda ba kawai dan kadan inganta da lankwasawa ƙarfi da compressive ƙarfi na turmi, sabõda haka, cohesiveness da danko na ciminti turmi ne mafi dace da shafi yi, amma kuma muhimmanci inganta ruwa riƙewa. iyawar turmi idan aka kwatanta da ether cellulose guda ɗaya. Xu Qi et al. ƙara slag foda, ruwa rage wakili da HEMc, da kuma gano cewa rage ruwa wakili da kuma ma'adinai foda iya kara yawa na turmi, rage yawan ramukan, don inganta ƙarfi da na roba modulus na turmi. HEMc na iya ƙara ƙarfin haɗin gwiwa na turmi, amma ba shi da kyau ga ƙarfin matsawa da na roba na turmi. Yang Xiaojie et al. gano cewa za a iya rage raguwar raguwar filastik na turmi siminti bayan haɗe HEMc da PP fiber.

6. Kammalawa

Nonionic cellulose ether yana taka muhimmiyar rawa a cikin ciminti na polymer, wanda zai iya inganta halayen jiki sosai (ciki har da retarding coagulation, riƙewar ruwa, thickening), ƙananan ƙwayoyin cuta da kayan aikin injiniya na siminti turmi. An yi ayyuka da yawa a kan gyare-gyaren kayan da aka yi da siminti ta hanyar cellulose ether, amma har yanzu akwai wasu matsalolin da ke buƙatar ƙarin nazari. Alal misali, a aikace-aikacen injiniya mai amfani, an ba da hankali sosai ga rheology, kaddarorin nakasa, kwanciyar hankali na girma da kuma dorewa na kayan da aka gyara na siminti, kuma ba a kafa dangantaka ta yau da kullum tare da ƙarin ether cellulose ba. Binciken kan hanyar ƙaura na cellulose ether polymer da samfuran hydration na siminti a cikin halayen hydration har yanzu bai isa ba. Tsarin aiki da tsarin abubuwan abubuwan da suka hada da cellulose ether da sauran addmixtures ba su da kyau sosai. Abubuwan da aka haɗa na ether cellulose da kayan ƙarfafa inorganic kamar fiber gilashin bai cika ba. Duk waɗannan za su zama abin da ake mayar da hankali ga bincike na gaba don samar da jagorar ka'idar don ƙara inganta aikin simintin polymer.