Cellulose ether muzinthu za simenti

Cellulose ether ndi mtundu wa zowonjezera zomwe zimagwiritsidwa ntchito pazinthu za simenti. Pepalali likuwonetsa mankhwala a methyl cellulose (MC) ndi hydroxypropyl methyl cellulose (HPMC /) omwe amagwiritsidwa ntchito kwambiri popanga simenti, njira ndi mfundo za yankho la ukonde ndi mawonekedwe akulu a yankho. Kutsika kwa kutentha kwa gel osakaniza ndi kukhuthala kwa zinthu za simenti kunakambidwa potengera zomwe zidachitika popanga.

Mawu ofunikira:cellulose ether; methyl cellulose;Hydroxypropyl methyl cellulose; Kutentha kwa gel osakaniza; mamasukidwe akayendedwe

1. Mwachidule

Cellulose ether (CE mwachidule) amapangidwa ndi mapadi kudzera mu etherification reaction ya imodzi kapena zingapo zopangira etherifying ndi kugaya youma. CE ikhoza kugawidwa mu mitundu ya ionic ndi yosakhala ya ionic, yomwe siionic mtundu wa CE chifukwa cha mawonekedwe ake apadera a gel osakaniza ndi kusungunuka, kukana mchere, kukana kutentha, ndipo imakhala ndi ntchito yoyenera pamwamba. Itha kugwiritsidwa ntchito ngati chosungira madzi, kuyimitsidwa, emulsifier, kupanga filimu, mafuta, zomatira ndi rheological improver. Malo akuluakulu ogwiritsira ntchito kunja ndi zokutira latex, zomangira, kubowola mafuta ndi zina zotero. Poyerekeza ndi mayiko akunja, kupanga ndi kugwiritsa ntchito makina osungunuka m'madzi a CE akadali achichepere. Ndi kusintha kwa thanzi la anthu komanso chidziwitso cha chilengedwe. CE wosungunuka m'madzi, womwe ulibe vuto ku physiology ndipo suipitsa chilengedwe, udzakhala ndi chitukuko chachikulu.

Pazinthu zomangira zomwe nthawi zambiri zimasankhidwa CE ndi methyl cellulose (MC) ndi hydroxypropyl methyl cellulose (HPMC), zitha kugwiritsidwa ntchito ngati utoto, pulasitala, matope ndi zinthu za simenti, plasticizer, viscosifier, posungira madzi, wothandizira mpweya komanso wochepetsa. Ambiri mwa makampani zomangira ntchito pa kutentha yachibadwa, ntchito zinthu ndi youma Kusakaniza ufa ndi madzi, zochepa zokhudza makhalidwe Kusungunuka ndi makhalidwe otentha gel osakaniza CE, koma kupanga makina simenti mankhwala ndi zina zapadera kutentha, makhalidwe amenewa CE itenga gawo lathunthu.

2. Chemical katundu wa CE

CE imapezeka pochiza cellulose kudzera m'njira zingapo zamankhwala komanso zakuthupi. Malinga ndi kapangidwe kake ka m'malo ka mankhwala, nthawi zambiri amatha kugawidwa kukhala: MC, HPMC, hydroxyethyl cellulose (HEC), ndi zina: CE iliyonse imakhala ndi kapangidwe ka cellulose - shuga wopanda madzi. Popanga CE, ulusi wa cellulose umayamba kutenthedwa mu njira ya alkaline kenako ndikuthiridwa ndi etherifying agents. The fibrous reaction mankhwala amayeretsedwa ndi pulverized kupanga yunifolomu ufa wa fineness inayake.

Njira yopangira MC imangogwiritsa ntchito methane chloride ngati etherifying agent. Kuphatikiza pa kugwiritsa ntchito methane chloride, kupanga kwa HPMC kumagwiritsanso ntchito propylene oxide kupeza magulu olowa m'malo a hydroxypropyl. Zosiyanasiyana za CE zimakhala ndi ma methyl ndi hydroxypropyl m'malo osiyanasiyana, zomwe zimakhudza kuyanjana kwa organic ndi kutentha kwa gel osakaniza yankho la CE.

Chiwerengero cha magulu olowa m'malo pamagulu a cellulose omwe alibe madzi am'thupi amatha kuwonetsedwa ndi kuchuluka kwa misa kapena kuchuluka kwamagulu olowa m'malo (ie, DS - Degree of Substitution). Kuchuluka kwa magulu olowa m'malo kumatsimikizira zomwe zili muzogulitsa za CE. Zotsatira za gawo lapakati pa kusungunuka kwa zinthu za etherification ndi motere:

(1) digirii yotsika m'malo yosungunuka mu lye;

(2) mlingo wapamwamba pang'ono wa m'malo wosungunuka m'madzi;

(3) mkulu mlingo wa m'malo kusungunuka mu polar organic solvents;

(4) Mlingo wapamwamba m'malo kusungunuka mu sanali polar organic solvents.

3. Njira yothetsera CE

CE ili ndi katundu wapadera wosungunuka, pamene kutentha kumakwera kutentha kwina, sikusungunuka m'madzi, koma pansi pa kutentha kumeneku, kusungunuka kwake kudzawonjezeka ndi kuchepa kwa kutentha. CE imasungunuka m'madzi ozizira (ndipo nthawi zina m'madzi osungunulira organic) kudzera mu kutupa ndi hydration. Mayankho a CE alibe malire osungunuka omwe amawonekera pakusungunuka kwa mchere wa ionic. Kuchuluka kwa CE nthawi zambiri kumangokhala ndi mamasukidwe akayendedwe omwe amatha kuwongoleredwa ndi zida zopangira, komanso amasiyana malinga ndi kukhuthala ndi mitundu yamankhwala yomwe wogwiritsa ntchito amafunikira. Njira yothetsera kukhuthala kotsika kwa CE nthawi zambiri imakhala 10% ~ 15%, ndipo kukhuthala kwakukulu CE nthawi zambiri kumakhala 2% ~ 3%. Mitundu yosiyanasiyana ya CE (monga ufa kapena ufa wothira pamwamba kapena granular) imatha kukhudza momwe yankho limakonzedwera.

3.1 CE popanda chithandizo chapamwamba

Ngakhale CE imasungunuka m'madzi ozizira, iyenera kubalalitsidwa kwathunthu m'madzi kuti isagwe. Nthawi zina, chosakanizira chothamanga kwambiri kapena chophatikizira chingagwiritsidwe ntchito m'madzi ozizira kuti abalalitse ufa wa CE. Komabe, ngati ufa wosayeretsedwawo uwonjezedwa m'madzi ozizira popanda kugwedezeka mokwanira, zotupa zazikulu zimapangika. Chifukwa chachikulu chopangira makeke ndikuti tinthu tating'ono ta CE sizonyowa kwathunthu. Pamene gawo limodzi la ufa litasungunuka, filimu ya gel idzapangidwa, yomwe imalepheretsa ufa wotsalawo kuti usapitirize kusungunuka. Chifukwa chake, tisanawonongeke, tinthu tating'ono ta CE tikuyenera kubalalitsidwa mokwanira momwe tingathere. Njira ziwiri zotsatirazi zobalalitsira zimagwiritsidwa ntchito kwambiri.

3.1.1 Njira yobalalitsira yowuma

Njira imeneyi imagwiritsidwa ntchito kwambiri popanga simenti. Musanawonjezere madzi, sakanizani ufa wina ndi ufa wa CE mofanana, kuti tinthu tating'ono ta CE timwazike. Kusakaniza kocheperako: ufa wina: CE ufa =(3 ~ 7): 1.

Mwanjira iyi, kubalalitsidwa kwa CE kumatsirizika pamalo owuma, pogwiritsa ntchito ufa wina ngati sing'anga kufalitsa tinthu tating'onoting'ono tomwe titha kupewetsa kulumikizana kwa tinthu tating'onoting'ono ta CE tikamawonjezera madzi ndikusintha kusungunuka kwina. Choncho, madzi otentha si chofunika kubalalitsidwa, koma kuvunda mlingo zimadalira ufa particles ndi yoyambitsa zinthu.

3.1.2 Njira yobalalitsira madzi otentha

(1) Yoyamba 1/5 ~ 1/3 yofunikira yotenthetsera madzi mpaka 90C pamwamba, onjezerani CE, ndiyeno yambitsani mpaka tinthu tating'ono ting'onoting'ono tanyowa, ndiyeno madzi otsalawo m'madzi ozizira kapena oundana amawonjezeredwa kuti muchepetse kutentha kwa yankho, kamodzi anafika kutentha kutentha kutentha, ufa anayamba hydrate, mamasukidwe akayendedwe anawonjezeka.

(2) Mukhozanso kutentha madzi onse, ndiyeno onjezerani CE kusonkhezera pamene mukuzizira mpaka hydration itatha. Kuziziritsa kokwanira ndikofunikira kwambiri kuti hydrate yathunthu ya CE ipangike komanso kupanga mamasukidwe akayendedwe. Pakukhuthala koyenera, yankho la MC liyenera kukhazikika mpaka 0 ~ 5 ℃, pomwe HPMC imangofunika kuzizidwa mpaka 20 ~ 25 ℃ kapena pansi. Popeza kuti hydration yathunthu imafuna kuziziritsa kokwanira, njira za HPMC zimagwiritsidwa ntchito pomwe madzi ozizira sangagwiritsidwe ntchito: malinga ndi chidziwitso, HPMC imakhala ndi kuchepetsa kutentha pang'ono kuposa MC pa kutentha kochepa kuti ikwaniritse kukhuthala komweku. Ndizofunikira kudziwa kuti njira yobalalitsira madzi otentha imangopangitsa kuti tinthu tating'onoting'ono ta CE tizibalalika mofanana pa kutentha kwakukulu, koma palibe yankho lomwe limapangidwa panthawiyi. Kuti mupeze yankho ndi viscosity inayake, iyenera kukhazikikanso.

3.2 Pamwamba amathandizidwa ndi dispersible CE ufa

Nthawi zambiri, CE imayenera kukhala ndi mawonekedwe otayika komanso othamanga (kupanga mamasukidwe) m'madzi ozizira. Pamwamba pothandizidwa ndi CE sisungunuka kwakanthawi m'madzi ozizira pambuyo pa mankhwala apadera, omwe amawonetsetsa kuti CE ikawonjezedwa m'madzi, sipanga mawonekedwe owoneka bwino ndipo imatha kubalalitsidwa pansi pamikhalidwe yaying'ono yometa ubweya. "Nthawi yochedwa" ya hydration kapena viscosity mapangidwe ndi zotsatira za kuphatikiza kwa mlingo wa mankhwala pamwamba, kutentha, pH ya dongosolo, ndi CE yankho ndende. Kuchedwa kwa hydration nthawi zambiri kumachepetsedwa pamlingo wokwera, kutentha, ndi pH milingo. Mwambiri, komabe, kuchuluka kwa CE sikuganiziridwa mpaka kukafika 5% (chiwerengero chamadzi).

Pazotsatira zabwino kwambiri komanso hydration yathunthu, malo omwe amathandizidwa ndi CE ayenera kugwedezeka kwa mphindi zingapo osalowerera ndale, pH ya 8.5 mpaka 9.0, mpaka kukhuthala kwakukulu kufikire (nthawi zambiri mphindi 10-30). Pamene pH ikusintha kukhala yofunikira (pH 8.5 mpaka 9.0), pamwamba amathandizidwa ndi CE amasungunuka kwathunthu komanso mofulumira, ndipo yankho likhoza kukhala lokhazikika pa pH 3 mpaka 11. Komabe, nkofunika kuzindikira kuti kusintha pH ya slurry yapamwamba. zidzapangitsa mamasukidwe akayendedwe kukhala okwera kwambiri popopa ndi kuthira. PH iyenera kusinthidwa pambuyo poti slurry yachepetsedwa mpaka ndende yomwe mukufuna.

Mwachidule, kusungunuka kwa CE kumaphatikizapo njira ziwiri: kubalalitsidwa kwathupi ndi kusungunuka kwa mankhwala. Chinsinsi ndi kumwazikana CE particles wina ndi mzake pamaso kuvunda, kuti kupewa agglomeration chifukwa mkulu mamasukidwe akayendedwe pa otsika kutentha kuvunda, zimene zingakhudze zina kuvunda.

4. Katundu wa CE yankho

Mitundu yosiyanasiyana yamayankho amadzi a CE idzasungunuka pa kutentha kwake. Gelisiyo imasinthika kwathunthu ndipo imapanga yankho ikakhazikikanso. Thermal gelation ya CE ndi yapadera. Mu mankhwala ambiri simenti, ntchito yaikulu mamasukidwe akayendedwe a CE ndi lolingana madzi posungira ndi kondomu katundu, ndi mamasukidwe akayendedwe ndi gel osakaniza kutentha ali ndi ubale wachindunji, pansi pa kutentha gel osakaniza, m'munsi kutentha, ndi apamwamba mamasukidwe akayendedwe a CE, kumapangitsanso kuti madzi asungidwe bwino.

Kufotokozera kwapano kwa zochitika za gel ndi izi: pakutha, izi ndizofanana.

Mamolekyu a polima a ulusiwo amalumikizana ndi gawo la madzi, zomwe zimapangitsa kutupa. Mamolekyu amadzi amakhala ngati mafuta opaka mafuta, omwe amatha kutulutsa unyolo wautali wa mamolekyu a polima, kotero kuti yankho limakhala ndi mawonekedwe amadzimadzi owoneka bwino omwe ndi osavuta kutaya. Pamene kutentha kwa yankho kumawonjezeka, cellulose polima pang'onopang'ono amataya madzi ndipo kukhuthala kwa yankho kumachepa. Gel point ikafika, polima imakhala yopanda madzi okwanira, zomwe zimapangitsa kuti pakhale mgwirizano pakati pa ma polima ndi mapangidwe a gel: mphamvu ya gel ikupitirizabe kuwonjezeka pamene kutentha kumakhala pamwamba pa gel osakaniza.

Pamene yankho likuzizira, gel osakaniza amayamba kusintha ndipo kukhuthala kumachepa. Potsirizira pake, kukhuthala kwa njira yozizirira kumabwereranso kumalo oyambirira a kutentha kwa kutentha ndikuwonjezeka ndi kuchepa kwa kutentha. Njira yothetsera vutoli ikhoza kukhazikika pamtengo wake woyamba wa viscosity. Chifukwa chake, njira yotenthetsera ya gel ya CE imasinthidwa.

Udindo waukulu wa CE muzinthu za simenti ndi monga viscosifier, plasticizer ndi wosungira madzi, kotero momwe mungasamalire mamasukidwe akayendedwe ndi kutentha kwa gel osakaniza kwakhala chinthu chofunikira kwambiri pazinthu za simenti nthawi zambiri zimagwiritsa ntchito kutentha kwake koyambirira kwa gel pansi pa gawo la mphira, kotero kutsika kwa kutentha, kukwezeka kwa viscosity, kumakhalanso koonekeratu zotsatira za kusunga madzi kwa viscosifier. Zotsatira zoyeserera za mzere wopangira simenti wa extrusion zikuwonetsanso kuti kutsika kwa kutentha kwa zinthu kumakhala pansi pa zomwe zili mu CE, m'pamenenso kukhathamiritsa kwa ma viscosification ndi kusunga madzi kumakhala bwino. Popeza simenti ndi njira yovuta kwambiri yakuthupi ndi mankhwala, pali zinthu zambiri zomwe zimakhudza kusintha kwa kutentha kwa gelisi ya CE ndi kukhuthala. Ndipo chikoka cha mitundu yosiyanasiyana ya Taianin ndi digiri sizofanana, kotero ntchito yothandiza idapezanso kuti pambuyo posakaniza simenti, kutentha kwenikweni kwa gel osakaniza ndi CE (ndiko kuti, guluu ndi kusunga madzi kutsika kumawonekera kwambiri pakutentha uku. ) ndi otsika kuposa kutentha kwa gel opangidwa ndi mankhwala, choncho, posankha zinthu za CE kuti aganizire zomwe zimayambitsa kutentha kwa gel osakaniza. Zotsatirazi ndizinthu zazikulu zomwe timakhulupirira kuti zimakhudza kukhuthala ndi kutentha kwa gel osakaniza a CE solution muzinthu za simenti.

4.1 Chikoka cha pH mtengo pa viscosity

MC ndi HPMC ndizopanda ma ionic, kotero kukhuthala kwa yankho kuposa kukhuthala kwa guluu wachilengedwe wa ionic kuli ndi kukhazikika kwa DH, koma ngati pH mtengo upitilira 3 ~ 11, pang'onopang'ono amachepetsa kukhuthala kwa ma viscosity. kutentha kwambiri kapena kusungirako kwa nthawi yayitali, makamaka yankho la viscosity. Kukhuthala kwa mankhwala a CE kumachepetsa mu asidi amphamvu kapena njira yolimba yoyambira, yomwe imachitika makamaka chifukwa cha kuchepa kwa madzi m'thupi kwa CE chifukwa cha maziko ndi asidi. Chifukwa chake, kukhuthala kwa CE nthawi zambiri kumatsika pang'onopang'ono m'malo amchere azinthu za simenti.

4.2 Mphamvu ya kutentha kwa kutentha ndi kusonkhezera pa ndondomeko ya gel osakaniza

Kutentha kwa gel point kumakhudzidwa ndi kuphatikizika kwa kutentha kwa kutentha ndi kumeta ubweya wa ubweya. Kuthamanga kwambiri komanso kutentha kwachangu kumawonjezera kutentha kwa gel osakaniza, komwe kumakhala kothandiza pazinthu za simenti zopangidwa ndi kusanganikirana kwamakina.

4.3 Mphamvu ya ndende pa gel osakaniza

Kuchulukitsa kuchuluka kwa yankho nthawi zambiri kumachepetsa kutentha kwa gel osakaniza, ndipo nsonga za gel otsika kukhuthala kwa CE ndizokwera kuposa za kukhuthala kwakukulu kwa CE. Monga DOW's METHOCEL A

Kutentha kwa gel osakaniza kumachepetsedwa ndi 10 ℃ pakuwonjezeka kulikonse kwa 2% pakupanga kwazinthu. Kuwonjezeka kwa 2% kwa zinthu zamtundu wa F kudzachepetsa kutentha kwa gel ndi 4 ℃.

4.4 Mphamvu zowonjezera pa matenthedwe a gelation

Pazinthu zomangira, zida zambiri ndi zamchere zamchere, zomwe zimakhudza kwambiri kutentha kwa gel osakaniza a CE yankho. Kutengera ngati chowonjezeracho chikugwira ntchito ngati coagulant kapena solubilizing agent, zowonjezera zina zimatha kukulitsa kutentha kwa gel osakaniza a CE, pomwe zina zimatha kuchepetsa kutentha kwa gel osakaniza a CE: mwachitsanzo, ethanol yowonjezera mosungunulira, PEG-400 (polyethylene glycol) , anediol, etc., akhoza kuwonjezera gel osakaniza. Mchere, glycerin, sorbitol ndi zinthu zina zimachepetsa gel osakaniza, omwe si-ionic CE nthawi zambiri sadzakhala mpweya chifukwa cha ayoni zitsulo za polyvalent, koma ngati ndende ya electrolyte kapena zinthu zina zosungunuka zidutsa malire, zinthu za CE zimatha kuthiridwa mchere. yankho, izi zimachitika chifukwa cha mpikisano wa ma electrolyte m'madzi, zomwe zimapangitsa kuchepa kwa hydration ya CE, Mchere wothira muzitsulo za CE nthawi zambiri umakhala wokwera pang'ono kuposa wa Mc, ndipo mcherewo ndi wosiyana pang'ono. mu HPMC zosiyanasiyana.

Zosakaniza zambiri muzinthu za simenti zimapangitsa kuti gel ole agwere ku CE, chifukwa chake kusankha zowonjezera ziyenera kuganizira kuti izi zitha kupangitsa kuti gel point ndi mamasukidwe a CE asinthe.

5.Mapeto

(1) cellulose ether ndi cellulose wachilengedwe kudzera mu etherification reaction, ali ndi gawo lofunikira la shuga wopanda madzi, malinga ndi mtundu ndi kuchuluka kwa magulu olowa m'malo ake ndipo ali ndi zinthu zosiyanasiyana. The non-ionic ether monga MC ndi HPMC angagwiritsidwe ntchito ngati viscosifier, wothandizila madzi posungira, mpweya intrainment wothandizila ndi zina ntchito kwambiri mu zomangira katundu.

(2) CE imakhala ndi kusungunuka kwapadera, kupanga yankho pa kutentha kwina (monga kutentha kwa gel), ndikupanga gel olimba kapena osakaniza tinthu tating'ono pa kutentha kwa gel. Njira zazikulu zowonongeka ndi njira yowuma yosakaniza yobalalitsira, njira yobalalitsira madzi otentha, ndi zina zotero, muzinthu za simenti zomwe zimagwiritsidwa ntchito kwambiri ndi njira yosakaniza yowuma yobalalitsa. Chofunikira ndikumwaza CE mofananamo isanasungunuke, kupanga yankho pakutentha kotsika.

(3) Solution ndende, kutentha, pH mtengo, mankhwala katundu wa zina ndi yogwira mlingo zingakhudze gel osakaniza kutentha ndi mamasukidwe akayendedwe a njira CE, makamaka mankhwala simenti ndi inorganic mchere njira mu zamchere chilengedwe, kawirikawiri kuchepetsa gel osakaniza kutentha ndi mamasukidwe akayendedwe a CE yankho. , kubweretsa zotsatira zoyipa. Choncho, molingana ndi makhalidwe a CE, choyamba, iyenera kugwiritsidwa ntchito pa kutentha kochepa (pansi pa kutentha kwa gel), ndipo kachiwiri, mphamvu ya zowonjezera ziyenera kuganiziridwa.