Cellulose ether ndi polima wopangidwa kuchokera ku cellulose wachilengedwe kudzera mukusintha kwamankhwala. Cellulose ether ndi chochokera ku cellulose yachilengedwe. Kupanga kwa cellulose ether ndikosiyana ndi ma polima opangira. Zinthu zake zofunika kwambiri ndi cellulose, gulu lachilengedwe la polima. Chifukwa cha mawonekedwe achilengedwe a cellulose, cellulose palokha sangathe kuchitapo kanthu ndi etherification agents. Komabe, pambuyo pochiza chotupa chotupa, zomangira zamphamvu za haidrojeni pakati pa unyolo wa maselo ndi unyolo zimawonongeka, ndipo kutulutsidwa kogwira kwa gulu la hydroxyl kumakhala cellulose yotakata. Pezani cellulose ether.
Makhalidwe a cellulose ethers amadalira mtundu, chiwerengero ndi kugawa kwa zolowa m'malo. Magulu a cellulose ethers amatengeranso mtundu wa zolowa m'malo, digiri ya etherification, solubility ndi mawonekedwe ogwiritsira ntchito. Malinga ndi mtundu wa zolowa m'malo pa unyolo wa maselo, imatha kugawidwa kukhala monoether ndi ether wosakanikirana. Nthawi zambiri timagwiritsa ntchito mc ngati monoether, ndi HPmc ngati ether yosakanikirana. Methyl cellulose ether mc ndi chinthu chopangidwa pambuyo pa gulu la hydroxyl pagawo la shuga wa cellulose wachilengedwe m'malo mwa methoxy gulu. Ndi chinthu chopezedwa polowa m'malo mwa gulu la hydroxyl pagawo ndi gulu la methoxy ndi gawo lina ndi gulu la hydroxypropyl. Mapangidwe ake ndi [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)CH3]n]x Hydroxyethyl methyl cellulose ether HEmc, iyi ndi mitundu ikuluikulu yomwe imagwiritsidwa ntchito kwambiri ndikugulitsidwa pamsika.
Pankhani ya solubility, imatha kugawidwa kukhala ionic ndi non-ionic. Ma etha osungunuka m'madzi omwe si a ionic cellulose amapangidwa makamaka ndi ma alkyl ethers ndi ma hydroxyalkyl ethers. Ionic Cmc imagwiritsidwa ntchito makamaka mu zotsukira zopangira, kusindikiza nsalu ndi utoto, kufufuza zakudya ndi mafuta. Non-ionic mc, HPmc, HEmc, etc. amagwiritsidwa ntchito makamaka muzomangamanga, zokutira latex, mankhwala, mankhwala tsiku ndi tsiku, etc. Ntchito ngati thickener, madzi kusunga wothandizila, stabilizer, dispersant ndi filimu kupanga wothandizira.
Kusungirako madzi kwa cellulose ether
Popanga zida zomangira, makamaka matope osakanikirana owuma, ether ya cellulose imagwira ntchito yosasinthika, makamaka popanga matope apadera (matope osinthidwa), ndi gawo lofunikira komanso lofunikira.
Ntchito yofunika kwambiri ya madzi sungunuka mapadi etero mu matope makamaka ali mbali zitatu, mmodzi kwambiri madzi posungira mphamvu, wina ndi chikoka pa kusasinthasintha ndi thixotropy wa matope, ndipo chachitatu ndi mogwirizana ndi simenti.
Mphamvu yosungira madzi ya cellulose ether imadalira kuyamwa kwamadzi kwa gawo loyambira, kapangidwe ka matope, makulidwe a matope, kuchuluka kwa madzi kwa matope, komanso nthawi yoyika zinthu. Kusungidwa kwamadzi kwa cellulose ether komweko kumachokera ku kusungunuka ndi kutaya madzi m'thupi kwa cellulose ether yokha. Monga ife tonse tikudziwa, ngakhale cellulose maselo unyolo muli ambiri hydratable OH magulu kwambiri hydratable, si sungunuka m'madzi, chifukwa mapadi kapangidwe ndi mkulu digiri crystallinity. Mphamvu ya hydration yamagulu a hydroxyl yokha sikokwanira kuphimba zomangira zamphamvu za haidrojeni ndi mphamvu za van der Waals pakati pa mamolekyu. Choncho, zimangotupa koma sizisungunuka m'madzi. Pamene cholowa m'malo anadzetsa mu unyolo maselo, osati m'malo kuwononga unyolo wa haidrojeni, komanso interchain wa haidrojeni chomangira anawonongedwa chifukwa wedging wa m'malo pakati moyandikana unyolo. Cholowa m'malo chimakhala chachikulu, ndiye kuti mtunda pakati pa mamolekyu ndi waukulu. Kuchuluka kwa mtunda. Zotsatira zazikulu za kuwononga zomangira za haidrojeni, cellulose ether imakhala yosungunuka m'madzi pambuyo poti latisi ya cellulose ikuchulukira ndipo yankho limalowa, ndikupanga yankho lapamwamba kwambiri. Kutentha kukakwera, hydration ya polima imafooka, ndipo madzi pakati pa maunyolo amathamangitsidwa. Pamene kuchepa madzi m'thupi zotsatira zokwanira, mamolekyu amayamba aggregate, kupanga atatu azithunzithunzi maukonde dongosolo gel osakaniza ndi apangidwe kunja. Zomwe zimakhudza kusungidwa kwamadzi mumatope zimaphatikizapo kukhuthala kwa cellulose ether, kuchuluka kwake, kununkhira kwa tinthu tating'ono komanso kutentha kwa ntchito.
Kukwezeka kwa kukhuthala kwa cellulose ether, kumapangitsa kuti madzi asamasungidwe bwino, komanso kukulitsa kukhuthala kwa njira ya polima. Kutengera kulemera kwa maselo (digiri ya polymerization) ya polima, imatsimikiziridwanso ndi kutalika kwa unyolo wa kapangidwe ka maselo ndi mawonekedwe a unyolo, komanso kugawa kwamitundu ndi kuchuluka kwa zolowa m'malo kumakhudzanso kukhuthala kwake. [η]=Km
[η] Intrinsic viscosity ya polymer solution
m polima molekyulu kulemera
α polima khalidwe mosasintha
K kukhuthala kwamphamvu kokwanira
Kukhuthala kwa njira ya polima kumadalira kulemera kwa ma polima. The mamasukidwe akayendedwe ndi ndende ya cellulose ether njira zimagwirizana ndi ntchito m'madera osiyanasiyana. Choncho, aliyense mapadi efa ali zosiyanasiyana kukhuthala kwa kukhuthala kwa makulidwe, ndi kusintha mamasukidwe akayendedwe makamaka anazindikira ndi kuwonongeka kwa alkali mapadi, ndiko kuti, kusweka kwa mapadi unyolo maselo.
Kuchuluka kwa cellulose ether kuwonjezeredwa kumatope, kumapangitsa kuti madzi asamasungidwe bwino, komanso kukwezeka kwa viscosity, ndi bwino kusunga madzi.
Pa kukula kwa tinthu, tinthu tating'onoting'ono timakhala tomwe timasunga madzi bwino (onani Chithunzi 3). Pambuyo pa tinthu tating'ono ta cellulose ether takumana ndi madzi, pamwamba pake nthawi yomweyo amasungunuka ndikupanga gel osakaniza kuti ateteze mamolekyu amadzi kuti asapitirire kulowa. Nthawi zina sangathe kumwazikana mofanana ndi kusungunuka ngakhale atagwedezeka kwa nthawi yaitali, kupanga njira yothetsera mitambo kapena agglomeration. Zimakhudza kwambiri kusungidwa kwamadzi kwa cellulose ether, ndipo kusungunuka ndi chimodzi mwazinthu zomwe zimasankha cellulose ether.
Thickening ndi Thixotropy wa Cellulose Ether
Ntchito yachiwiri ya cellulose ether - thickening zimadalira: mlingo wa polymerization wa mapadi efa, njira ndende, kukameta ubweya mlingo, kutentha ndi zina. Katundu wa gelling wa yankho ndi wapadera kwa alkyl cellulose ndi zotuluka zake zosinthidwa. Makhalidwe a gelation amakhudzana ndi kuchuluka kwa m'malo, ndende ya yankho ndi zowonjezera. Kwa zotumphukira zosinthidwa za hydroxyalkyl, mawonekedwe a gel amalumikizananso ndi digiri yakusintha kwa hydroxyalkyl. Pakuti mc ndi HPmc ndi kukhuthala otsika, 10% -15% ndende njira akhoza kukonzekera, 5% -10% yankho akhoza kukonzekera sing'anga mamasukidwe akayendedwe kukhuthala mc ndi HPmc, ndi 2% -3% yankho akhoza kukonzekera mkulu mamasukidwe akayendedwe mc ndi HPmc, ndipo kawirikawiri Gulu la viscosity la cellulose ether limayikidwanso ndi 1% -2% yankho. High molecular kulemera cellulose ether ali mkulu thickening dzuwa. Munjira yofananira, ma polima okhala ndi zolemetsa zosiyanasiyana zama cell amakhala ndi ma viscosity osiyanasiyana. Madigiri apamwamba. Chandamale mamasukidwe akayendedwe angapezeke kokha ndi kuwonjezera kuchuluka otsika maselo kulemera cellulose ether. Kukhuthala kwake kumadalira pang'ono kumeta ubweya wa ubweya, ndipo kukhuthala kwapamwamba kumafika kukhuthala kwa chandamale, ndipo kuchuluka komwe kumafunikira kumakhala kochepa, ndipo kukhuthala kumadalira kukhuthala kwamphamvu. Choncho, kuti akwaniritse kusasinthasintha kwina, kuchuluka kwa cellulose ether (kukhazikika kwa yankho) ndi kukhuthala kwa yankho ziyenera kutsimikiziridwa. Kutentha kwa gel osakaniza kumachepetsanso mofanana ndi kuwonjezeka kwa ndende ya yankho, ndi gel osakaniza kutentha kwa firiji atatha kufika pamtundu wina. Kuchuluka kwa gelation kwa HPmc ndikokwera kwambiri kutentha.
Kusasinthasintha kungasinthidwenso posankha kukula kwa tinthu ndikusankha ma cellulose ethers ndi magawo osiyanasiyana akusintha. Chomwe chimatchedwa kusinthidwa ndikuyambitsa njira ina yosinthira magulu a hydroxyalkyl pamapangidwe a mafupa a mc. Posintha zikhalidwe zolowa m'malo mwazolowa m'malo awiriwo, ndiye kuti, DS ndi ms m'malo mwa magulu a methoxy ndi hydroxyalkyl omwe timanena nthawi zambiri. Zofunikira zosiyanasiyana zogwirira ntchito za cellulose ether zitha kupezeka posintha kusintha kwazinthu ziwirizo.
Ma cellulose ethers omwe amagwiritsidwa ntchito muzomangamanga za ufa ayenera kusungunuka mwachangu m'madzi ozizira ndikupereka kusasinthika koyenera kwa dongosolo. Ngati atapatsidwa kumeta ubweya wina, amakhalabe wopindika komanso wamtundu wa colloidal, womwe ndi chinthu chotsikirapo kapena chosawoneka bwino.
Palinso ubale wabwino wa mzere pakati pa kusasinthika kwa phala la simenti ndi mlingo wa cellulose ether. Selulosi ether akhoza kwambiri kuonjezera mamasukidwe akayendedwe a matope. Mlingo wokulirapo, zotsatira zake zimawonekera, onani Chithunzi 6
High-viscosity cellulose ether amadzimadzi njira ali mkulu thixotropy, amenenso ndi khalidwe lalikulu la mapadi ether. Amadzimadzi njira za Mc-mtundu ma polima zambiri pseudoplastic ndi sanali thixotropic fluidity m'munsimu awo gel osakaniza kutentha, koma Newtonian otaya katundu pa otsika kukameta ubweya mitengo. Pseudoplasticity imawonjezeka ndi kulemera kwa maselo kapena kuchuluka kwa cellulose ether, mosasamala kanthu za mtundu wa cholowa m'malo ndi kuchuluka kwa m'malo. Choncho, ma cellulose ethers a kalasi yofanana ya viscosity, mosasamala kanthu za mc, HPmc, HEmc, nthawi zonse amawonetsa zofanana za rheological malinga ngati ndende ndi kutentha zimasungidwa nthawi zonse. Ma gels apangidwe amapangidwa pamene kutentha kumakwera, ndipo kutuluka kwa thixotropic kwambiri kumachitika. Mkulu ndende ndi otsika mamasukidwe akayendedwe mapadi ethers amasonyeza thixotropy ngakhale pansi pa kutentha gel osakaniza. Katunduyu ndiwopindulitsa kwambiri pakuwongolera kusanja ndi kugwa pakupanga matope omangira. Payenera kufotokozedwa apa kuti kukwezeka kwa kukhuthala kwa cellulose ether, kusungika kwamadzi kwabwino, koma kukhuthala kwamphamvu, kumapangitsanso kuchuluka kwa maselo a cellulose ether, komanso kuchepa kofananira ndi kusungunuka kwake, komwe kumakhala ndi zotsatira zoyipa. pa ndende yamatope ndi ntchito yomanga. The apamwamba mamasukidwe akayendedwe, zoonekeratu kwambiri thickening zotsatira pa matope, koma si kokwanira molingana. Kukhuthala kwina kwapakatikati ndi kotsika, koma ether yosinthidwa ya cellulose imakhala ndi magwiridwe antchito abwino pakuwongolera mphamvu zamapangidwe amatope onyowa. Ndi kuwonjezeka kwa mamasukidwe akayendedwe, kasungidwe kamadzi ka cellulose ether kumapita bwino.
Nthawi yotumiza: Nov-22-2022