Focus on Cellulose ethers

Cellulose ether mu matope osakaniza okonzeka

Udindo wofunikira wa cellulose ether mumatope osakanikirana:

Mu matope okonzeka osakaniza, kuchuluka kwa cellulose ether ndikochepa kwambiri, koma kumatha kusintha kwambiri magwiridwe antchito a matope onyowa, ntchito yomanga matope ndi chowonjezera chachikulu.Kusankhidwa koyenera kwamitundu yosiyanasiyana, kukhuthala kosiyanasiyana, kukula kwa tinthu tosiyanasiyana, digiri yamakayendedwe osiyanasiyana ndikuwonjezera kuchuluka kwa cellulose ether.

Mu matope okonzeka osakanikirana, kuchuluka kwa cellulose ether ndikochepa kwambiri, koma kumatha kusintha kwambiri magwiridwe antchito amatope onyowa, ntchito yomanga matope ndiyowonjezera kwambiri.Kusankhidwa koyenera kwa cellulose ether ndi mitundu yosiyanasiyana, kukhuthala kosiyanasiyana, kukula kwa tinthu tating'onoting'ono, digiri ya kukhuthala kosiyanasiyana komanso kuchuluka kwake kumakhudza kuwongolera kwamatope owuma.Pakalipano, matope ambiri omanga ndi pulasitala sakhala ndi ntchito yabwino yosungira madzi, ndipo kulekanitsa kwamadzi slurry kudzachitika pakangopita mphindi zochepa.

Kusungirako madzi ndi ntchito yofunika kwambiri ya methyl cellulose ether, komanso ambiri opanga matope owuma m'nyumba, makamaka kum'mwera kwa omwe amapanga kutentha kwambiri omwe amakhudzidwa ndi ntchitoyi.Zomwe zimakhudza momwe madzi amasungiramo matope owuma ndi monga kuchuluka kwa MC, MC viscosity, fineness ya tinthu ndi kutentha kozungulira.

Cellulose ether ndi polima wopangidwa ndi cellulose wachilengedwe monga zopangira posintha mankhwala.Ma cellulose ether amachokera ku cellulose yachilengedwe, kupanga cellulose ether ndi polima yopanga ndi yosiyana, zinthu zake zofunika kwambiri ndi cellulose, mankhwala achilengedwe a polima.Chifukwa cha mawonekedwe achilengedwe a cellulose, mapadi pawokha sangathe kuchitapo kanthu ndi etherifying agent.Komabe, pambuyo mankhwala a wothandizila kutupa, amphamvu haidrojeni zomangira pakati unyolo maselo ndi unyolo anawonongedwa, ndi ntchito ya hydroxyl gulu anamasulidwa mu alkali mapadi ndi mphamvu anachita, ndi mapadi etero analandira mwa anachita ETHERifying wothandizila - OH gulu mu -OR gulu.

Makhalidwe a cellulose ethers amadalira mtundu, chiwerengero ndi kugawa kwa zolowa m'malo.Magulu a cellulose ether amatengeranso mtundu wa zolowa m'malo, digiri ya etherification, solubility ndi ntchito yofananira imatha kugawidwa.Malinga ndi mtundu wa zolowa m'malo mwa unyolo wa mamolekyulu, imatha kugawidwa kukhala ether imodzi ndi ether yosakanikirana.MC nthawi zambiri imagwiritsidwa ntchito ngati etha imodzi, pomwe HPMC ndi ether yosakanikirana.Methyl cellulose ether MC ndi gawo lachilengedwe la cellulose glucose pa hydroxyl methoxide m'malo mwa kapangidwe kazinthu kachitidwe ndi [COH7O2 (OH) 3-H (OCH3) H] X, hydroxypropyl methyl cellulose ether HPMC ndi gawo pa gawo la hydroxyl la methoxide m'malo ndi hydroxypropyl, gawo lina la mankhwalawa limasinthidwa ndi hydroxypropyl, The structural formula ndi [C6H7O2 (OH) 3-MN (OCH3) M [OCH2CH (OH) CH3] N] X ndi hydroxyethyl methyl cellulose ether HEMC, yomwe ili amagwiritsidwa ntchito kwambiri ndikugulitsidwa pamsika.

Kuchokera ku solubility akhoza kugawidwa mu mtundu wa ionic ndi mtundu womwe si wa ionic.Madzi osungunuka omwe si a ionic cellulose ether amapangidwa makamaka ndi alkyl ether ndi hydroxyl alkyl ether mitundu iwiri ya mitundu.Ionic CMC imagwiritsidwa ntchito kwambiri popangira zotsukira, nsalu, kusindikiza, chakudya ndi kugwiritsa ntchito mafuta.Non-ionic MC, HPMC, HEMC ndi zina zomwe zimagwiritsidwa ntchito makamaka pomanga, zokutira latex, mankhwala, chemistry tsiku ndi tsiku ndi zina.Monga thickening wothandizira, madzi posungira wothandizira, stabilizer, dispersant, filimu kupanga wothandizira.

Ma cellulose etha kusungirako madzi: popanga zida zomangira, makamaka matope owuma, etha ya cellulose imagwira ntchito yosasinthika, makamaka popanga matope apadera (matope osinthidwa), komanso gawo lofunika kwambiri.Ntchito yofunika kwambiri ya madzi sungunuka mapadi etero mu matope makamaka ali mbali zitatu, mmodzi ndi kwambiri madzi posungira luso, chachiwiri ndi chikoka cha matope kusasinthasintha ndi thixotropy, ndipo chachitatu ndi mogwirizana ndi simenti.Kusungidwa kwa madzi a cellulose ether, kumadalira maziko a hydroscopicity, kapangidwe ka matope, makulidwe a matope, kufunikira kwa madzi amatope, nthawi yothira madzi.Kusungidwa kwamadzi kwa cellulose ether kumachokera ku kusungunuka ndi kutha kwa cellulose ether komweko.Ndizodziwika bwino kuti maunyolo a cellulose a cellulose, ngakhale ali ndi magulu ambiri a OH omwe ali ndi hydrated kwambiri, sasungunuka m'madzi chifukwa cha mawonekedwe awo a crystalline kwambiri.Mphamvu ya hydration ya magulu a hydroxyl okha sikokwanira kulipira ma intermolecular hydrogen bond ndi mphamvu za van der Waals.Pamene zolowa m'malo anadzetsa mu unyolo maselo, osati m'malo kuwononga unyolo haidrojeni, komanso interchain wa haidrojeni nsinga chifukwa wedging wa m'malo pakati moyandikana unyolo.Kukula kwa zolowa m'malo ndikokulirakulira kwa mtunda pakati pa mamolekyu.The kwambiri chiwonongeko cha haidrojeni chomangira kwenikweni, mapadi latisi kukula, njira mu mapadi efa amakhala madzi sungunuka, mapangidwe mkulu mamasukidwe akayendedwe njira.Pamene kutentha kumakwera, hydration ya polima imachepa ndipo madzi pakati pa maunyolo amatulutsidwa.Pamene kuchepa kwa madzi m'thupi kumakhala kokwanira, mamolekyu amayamba kusonkhanitsa ndipo gel osakaniza amapindika mumagulu atatu.

Zomwe zimakhudza kusungidwa kwamadzi mumatope ndi monga cellulose ether viscosity, mlingo, fineness wa tinthu ndi kutentha kwa utumiki.

Kuchuluka kwa kukhuthala kwa cellulose ether, kumapangitsa kuti madzi asungidwe bwino.Viscosity ndi gawo lofunikira la magwiridwe antchito a MC.Pakadali pano, opanga ma MC osiyanasiyana amagwiritsa ntchito njira ndi zida zosiyanasiyana kuyeza kukhuthala kwa MC.Njira zazikuluzikulu zikuphatikizapo Haake Rotovisko, Hoppler, Ubbelohde ndi Brookfield.Kwa mankhwala omwewo, zotsatira za viscosity zoyesedwa ndi njira zosiyanasiyana ndizosiyana kwambiri, zina zimakhala zosiyana.Chifukwa chake, poyerekeza mamasukidwe akayendedwe, ayenera kuchitidwa pakati pa njira yoyesera yofananira, kuphatikiza kutentha, rotor, ndi zina.

Nthawi zambiri, kukwezeka kwa mamachulukidwe kumapangitsa kuti madzi asungidwe bwino.Komabe, kukhuthala kwake kukakhala kokwezeka, kulemera kwa mamolekyu a MC ndikokwera kwambiri, ndipo kusungunuka kumachepa mofanana, zomwe zimakhudza mphamvu ndi ntchito yomanga yamatope.The apamwamba mamasukidwe akayendedwe, zoonekeratu kwambiri thickening zotsatira za matope, koma si wofanana ubale.Kukwezeka kwa viscosity, matope onyowa adzakhala omata kwambiri, zomangamanga zonse, ntchito ya scraper yomata komanso kumamatira kwambiri kuzinthu zoyambira.Koma sizothandiza kuwonjezera mphamvu zamapangidwe amatope onyowa.Pakumanga, ntchito yotsutsa-sag sizowonekera.M'malo mwake, ma viscosity ena otsika koma osinthidwa a methyl cellulose ether ali ndi ntchito yabwino kwambiri pakuwongolera mphamvu zamapangidwe amatope onyowa.

Kuchuluka kwa cellulose ether kumawonjezeredwa kumatope, kusungirako madzi kwabwinoko, kumapangitsa kuti ma viscosity akhale apamwamba, ntchito yabwino yosungira madzi.

Pa kukula kwa tinthu tating'onoting'ono, tinthu tating'onoting'ono timasunga bwino madzi.Large particles wa mapadi etere kukhudzana ndi madzi, pamwamba yomweyo kupasuka ndi kupanga gel osakaniza kukulunga zinthu kuteteza madzi mamolekyu kupitiriza kudutsa, nthawi zina yaitali yogwira ntchito sangathe wogawana omwazika kusungunuka, mapangidwe matope flocculent njira kapena agglomerate.Kusungunuka kwa cellulose ether ndi chimodzi mwazinthu zomwe mungasankhe cellulose ether.Fineness ndiwonso index yofunikira ya methyl cellulose ether.MC kwa matope youma amafuna ufa, otsika madzi okhutira, ndi fineness wa 20% ~ 60% tinthu kukula zosakwana 63um.Fineness imakhudza kusungunuka kwa methyl cellulose ether.Coarse MC kawirikawiri granular ndipo mosavuta kusungunuka m'madzi popanda agglomerating, koma Kutha liwiro ndi pang'onopang'ono, kotero si oyenera ntchito youma matope.Mu matope owuma, MC imamwazikana pakati pa zophatikiza, zodzaza bwino ndi zopangira simenti monga simenti, ndi ufa wokha womwe uli wokwanira ungapewe kuphatikizika kwa methyl cellulose ether posakanikirana ndi madzi.Pamene MC akuwonjezera madzi kupasuka agglomerate, ndi kovuta kumwazikana ndi kupasuka izo.MC ndi coarse fineness osati zinyalala, komanso amachepetsa m'deralo mphamvu ya matope.Pamene matope owuma otere amangidwa m'dera lalikulu, liwiro la kuchiritsa la matope owuma a m'deralo limachepetsedwa kwambiri, zomwe zimabweretsa kusweka chifukwa cha nthawi yochiritsa yosiyana.Kwa makina opopera matope, chifukwa cha nthawi yochepa yosakaniza, ubwino ndi wapamwamba.

Ubwino wa MC umakhalanso ndi chikoka pa kusunga madzi.Nthawi zambiri, methyl cellulose ether yokhala ndi mamasukidwe ofanana koma fineness yosiyana, momwe madzi amasungira bwino amakhala bwino pakuwonjezera komweko.

Kusungidwa kwa madzi kwa MC kumagwirizananso ndi kutentha komwe kumagwiritsidwa ntchito, ndipo kusungidwa kwa madzi kwa methyl cellulose ether kumachepa ndi kukwera kwa kutentha.Koma muzogwiritsidwa ntchito zenizeni, malo ambiri amatope owuma nthawi zambiri amakhala otentha kwambiri (opitilira madigiri 40) pansi pamikhalidwe yomanga mu gawo lapansi lotentha, monga chilimwe insolation ya kunja khoma putty pulasitala, amene nthawi zambiri imathandizira kulimba kwa simenti ndi kuumitsa matope.Kuchepa kwa kuchuluka kwa kusungirako madzi kumabweretsa kumverera koonekeratu kuti zonse zomanga ndi kukana kusweka zimakhudzidwa.Mu chikhalidwe ichi, kuchepetsa mphamvu ya kutentha zinthu kumakhala kovuta kwambiri.Ngakhale kuti chowonjezera cha methyl hydroxyethyl cellulose ether chimaonedwa kuti chili patsogolo pa chitukuko cha zamakono, kudalira kwake kutentha kudzachititsabe kufowoka kwa matope owuma.Ngakhale kuchuluka kwa mlingo wa methyl hydroxyethyl cellulose (chilinganizo cha chilimwe), kumanga ndi kukana kusweka sikungakwaniritse zosowa zogwiritsidwa ntchito.Kupyolera mu chithandizo chapadera cha MC, monga kuonjezera mlingo wa etherification, mphamvu yosungira madzi ya MC ikhoza kukhala ndi zotsatira zabwino pa kutentha kwakukulu, kotero kuti ikhoza kupereka ntchito yabwino pansi pa zovuta.

Komanso, mapadi efa thickening ndi thixotropy: mapadi etere chachiwiri kanthu - thickening zimadalira: mapadi etere polymerization digiri, njira ndende, kukameta ubweya mlingo, kutentha ndi zina.Katundu wa gelation wa yankho ndi wapadera kwa alkyl cellulose ndi zotuluka zake zosinthidwa.Makhalidwe a gelation amakhudzana ndi kuchuluka kwa kusintha, ndende ya yankho ndi zowonjezera.Pazinthu zosinthidwa za hydroxyl alkyl, katundu wa gel amalumikizananso ndi kuchuluka kwa kusinthidwa kwa hydroxyl alkyl.Pakuti yankho ndende ya otsika mamasukidwe akayendedwe MC ndi HPMC akhoza kukonzekera 10% -15% ndende njira, sing'anga mamasukidwe akayendedwe MC ndi HPMC akhoza kukonzekera 5% -10% njira, ndi mkulu mamasukidwe akayendedwe MC ndi HPMC akhoza kukhala okonzeka 2% -3 % yankho, ndipo kawirikawiri mapadi etere mamasukidwe masanjidwe kutengera ndi 1% -2% njira kalasi.Maselo apamwamba a cellulose ether thickener dzuwa, ndende yofanana ya yankho, ma polima osiyanasiyana olemera a maselo ali ndi kukhuthala kosiyana, kukhuthala kwa ma cell ndi kulemera kwa maselo kumatha kufotokozedwa motere, [η] = 2.92 × 10-2 (DPn) 0.905, DPn ndi avareji. polymerization digiri yapamwamba.Otsika maselo olemera mapadi efa kuwonjezera zambiri kukwaniritsa chandamale mamasukidwe akayendedwe.Kukhuthala kwake sikudalira kumeta ubweya wa ubweya, kukhuthala kwakukulu kuti akwaniritse kukhuthala kwa chandamale, kuchuluka komwe kumafunikira kuwonjezera pang'ono, kukhuthala kumadalira kukhuthala kwamphamvu.Chifukwa chake, kuti mukwaniritse kusasinthika kwina, kuchuluka kwa cellulose ether (concentration of solution) ndi ma viscosity yankho ziyenera kutsimikiziridwa.Kutentha kwa gelation kwa yankho kunachepa mofanana ndi kuwonjezeka kwa ndende ya yankho, ndipo gelation inachitika kutentha kwa firiji itatha kufika pamtundu wina.HPMC ali mkulu gelation ndende kutentha firiji.

Kusasinthasintha kungasinthidwenso posankha kukula kwa tinthu ndi ma cellulose ethers ndi magawo osiyanasiyana a kusinthidwa.Zomwe zimatchedwa kusinthidwa ndikuyambitsa gulu la hydroxyl alkyl mumlingo wina wolowa m'malo mwa mafupa a MC.Posintha zikhalidwe zolowa m'malo mwazolowa m'malo awiri, ndiko kuti, DS ndi MS m'malo mwa magulu a methoxy ndi hydroxyl.Makhalidwe osiyanasiyana a cellulose ether amafunikira posintha kusintha kwamitundu iwiri ya zolowa m'malo.

Ubale pakati pa kusasinthasintha ndi kusinthidwa: kuwonjezeredwa kwa cellulose ether kumakhudza kumwa madzi kwa matope, ndikusintha chiŵerengero cha madzi-binder cha madzi ndi simenti, chomwe chiri chowonjezera.Mlingo wokwera kwambiri, m'pamenenso amamwa madzi ambiri.

Ma cellulose ether omwe amagwiritsidwa ntchito muzomangamanga zaufa ayenera kusungunuka mwachangu m'madzi ozizira ndikupereka kusasinthika koyenera kudongosolo.Ngati kumeta ubweya wopatsidwa kukadali kosunthika komanso kosalala ndi chinthu chotsika kwambiri kapena chosawoneka bwino.

Palinso liniya ubale wabwino pakati pa simenti slurry kusasinthasintha ndi mlingo wa mapadi etere, mapadi ether akhoza kwambiri kuonjezera mamasukidwe akayendedwe matope, waukulu mlingo, ndi zoonekeratu zotsatira.Ma cellulose etere amadzimadzi njira ndi mkulu mamasukidwe akayendedwe ali mkulu thixotropy, amene ndi chimodzi mwa makhalidwe a mapadi efa.Amadzimadzi njira za MC mtundu ma polima zambiri pseudoplastic, sanali thixotropic fluidity m'munsimu awo gel osakaniza kutentha, koma Newtonian otaya katundu pa otsika kukameta ubweya mitengo.Pseudoplasticity imawonjezeka ndi kuchuluka kwa kulemera kwa maselo kapena kuchuluka kwa cellulose ether ndipo sizidalira mtundu ndi digiri.Choncho, ma cellulose ethers a kalasi yofanana ya viscosity, kaya MC, HPMC kapena HEMC, nthawi zonse amasonyeza zofanana za rheological malinga ngati ndende ndi kutentha kumakhalabe kosalekeza.Kutentha kumawonjezeka, gel osakaniza amapangidwa ndipo kuthamanga kwa thixotropic kumachitika.Ma cellulose ether okhala ndi ndende yayikulu komanso mawonekedwe otsika amawonetsa thixotropy ngakhale pansi pa kutentha kwa gel osakaniza.Katunduyu ndiwopindulitsa kwambiri pakumanga matope omangira kuti asinthe mayendedwe ake ndi kutuluka kwake komwe kumapachikidwa.Payenera kufotokozedwa apa kuti kukwezeka kwa kukhuthala kwa cellulose ether, kusungika kwamadzi kwabwinoko, koma kukhuthala kwamphamvu, kumapangitsa kuti maselo a cellulose ether achuluke, kuchepetsedwa kofananira kwa kusungunuka kwake, komwe kumakhudza kwambiri kuchuluka kwa matope ndi ntchito yomanga.The apamwamba mamasukidwe akayendedwe, zoonekeratu kwambiri thickening zotsatira za matope, koma si wathunthu kufanana ubale.Ena otsika mamasukidwe akayendedwe, koma kusinthidwa mapadi etero kuwongolera structural mphamvu ya chonyowa matope ali ndi ntchito yabwino kwambiri, ndi kuwonjezeka mamasukidwe akayendedwe, mapadi etere madzi posungira bwino.

Ma cellulose ether retardation: cellulose ether ntchito yachitatu ndikuchedwetsa njira ya hydration ya simenti.Cellulose etha endows matope ndi katundu osiyanasiyana opindulitsa, komanso amachepetsa oyambirira hydration kutentha kumasulidwa kwa simenti, kuchedwetsa hydration zamphamvu ndondomeko simenti.Izi sizothandiza kugwiritsa ntchito matope m'malo ozizira.Mtundu wa retarding zotsatira ndi mapadi etere molekyulu adsorption pa CSH ndi Ca (OH) 2 hydration mankhwala chifukwa, chifukwa cha kuchulukira kwa pore njira mamasukidwe akayendedwe, mapadi efa amachepetsa ntchito ayoni mu yankho, motero kuchedwa ndondomeko hydration.Kuchulukirachulukira kwa cellulose ether mu mineral gel zakuthupi, m'pamenenso zimawonekera kwambiri kuchedwa kwa hydration.Ma cellulose ether sikuti amangochedwetsa kukhazikitsa, komanso kuuma kwa dongosolo la matope a simenti.The retarding zotsatira za cellulose ether zimadalira ndende yake mu mchere gel osakaniza dongosolo, komanso dongosolo mankhwala.Kukwezeka kwa digiri ya HEMC methylation, kumapangitsanso kuchepa kwa cellulose ether.Kuchepetsa mphamvu ya hydrophilic m'malo ndi yamphamvu kuposa m'malo owonjezera madzi.Koma mamasukidwe akayendedwe a cellulose ether alibe mphamvu pa hydration kinetics ya simenti.

Ndi kuwonjezeka kwa cellulose ether okhutira, kuika nthawi ya matope kumawonjezeka kwambiri.Nthawi yoyamba yoyika matope imakhala ndi mgwirizano wabwino wa mzere ndi zomwe zili mu cellulose ether, ndipo nthawi yomaliza yokonzekera imakhala ndi mgwirizano wabwino wa mzere ndi zomwe zili mu cellulose ether.Titha kuwongolera nthawi yogwiritsira ntchito matope mwa kusintha mlingo wa cellulose ether.

Mwachidule, mumatope osakaniza okonzeka, cellulose ether imagwira ntchito posungira madzi, kukhuthala, kuchepetsa mphamvu ya simenti ya simenti, kupititsa patsogolo ntchito yomanga.Kutha kwabwino kusunga madzi kumapangitsa kuti simenti ikhale yokwanira, imatha kusintha kukhuthala konyowa kwa matope, kupititsa patsogolo mphamvu yomangira yamatope, nthawi yosinthika.Kuonjezera cellulose ether ku makina kupopera matope matope amatha kupititsa patsogolo kupopera kapena kupopera ntchito ndi mphamvu zamapangidwe amatope.Choncho, ether ya cellulose imagwiritsidwa ntchito kwambiri ngati chowonjezera chofunikira mumatope osakaniza okonzeka.


Nthawi yotumiza: Dec-17-2021
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