Eter cellulose waa polymer synthetic oo laga sameeyay cellulose dabiiciga ah iyada oo loo marayo isbeddel kiimiko ah.Cellulose ether waa nooc ka mid ah cellulose dabiiciga ah.Wax soo saarka ether-ka cellulose wuu ka duwan yahay polymers-ka synthetic.Maaddada ugu badan ee aasaasiga ah waa cellulose, oo ah ka samaysan polymer dabiici ah.Sababtoo ah gaar ahaan qaab dhismeedka cellulose ee dabiiciga ah, cellulose lafteedu awood uma laha inay ka falceliyaan wakiilada etherification.Si kastaba ha ahaatee, ka dib daaweynta wakiilka bararka, bonds hydrogen xoog badan oo u dhexeeya silsiladaha molecular iyo silsiladaha waa la burburiyaa, iyo sii daayo firfircoon ee kooxda hydroxyl waxay noqotaa cellulose alkali fal-celin ah.Hel ether cellulose.
Madaafiicda diyaarka ah ee isku dhafka ah, qadarka dheeriga ah ee ether cellulose waa mid aad u hooseeya, laakiin waxay si weyn u wanaajin kartaa waxqabadka hoobiye qoyan, waana wax lagu daro ugu weyn oo saameeya waxqabadka dhismaha ee hoobiye.Xulashada macquulka ah ee ethers cellulose ee noocyo kala duwan, viscosities kala duwan, cabbirrada kala duwan ee qaybaha kala duwan, heerarka kala duwan ee viscosity iyo qadarka lagu daray waxay saameyn togan ku yeelan doontaa hagaajinta waxqabadka hoobiye boodhka qalalan.Waqtigan xaadirka ah, qaar badan oo ka mid ah hoobiyeyaal dhoobo ah iyo kuwo dhejis ah ayaa leh waxqabad biyo celin ah oo liita, iyo qulqulka biyuhu way kala tagi doonaan ka dib dhowr daqiiqo oo taagan.
Haysashada biyuhu waa waxqabadka muhiimka ah ee methyl cellulose ether, sidoo kale waa waxqabad in qaar badan oo ka mid ah warshadeeyayaasha qalalan ee qallalan ee gudaha, gaar ahaan kuwa gobollada koonfureed ee leh heerkul sare, ay fiiro gaar ah u yeeshaan.Waxyaabaha saameeya saamaynta haynta biyaha ee hoobiye isku dhafka qallalan waxaa ka mid ah qadarka MC ee lagu daray, viscosity of MC, ganaaxyada walxaha iyo heerkulka deegaanka la isticmaalo.
Astaamaha ether-yada cellulose waxay ku xiran yihiin nooca, tirada iyo qaybinta beddelka.Kala soocida ethers cellulose waxay sidoo kale ku saleysan tahay nooca beddelka, heerka etherification, milanka iyo sifooyinka codsiga ee la xiriira.Marka loo eego nooca beddelka ee silsiladda molecular, waxaa loo qaybin karaa monoether iyo ether isku dhafan.MC-ka aan inta badan isticmaalno waa monoether, HPMC-guna waa eter isku dhafan.Methyl cellulose ether MC waa badeecada ka dib markii kooxda hydroxyl ee unugga gulukooska ee cellulose dabiiciga ah lagu beddelay methoxy.Qaabka qaabdhismeedku waa [COH7O2(OH)3-h(OCH3)h ]x.Qayb ka mid ah kooxda hydroxyl ee unugga waxa lagu beddelaa kooxda methoxy, qaybta kalena waxa lagu beddelaa kooxda hydroxypropyl, qaacidada qaabdhismeedku waa [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)CH3] n] x Ethyl methyl cellulose ether HEMC, kuwani waa noocyada ugu muhiimsan ee si weyn loo isticmaalo loogana iibiyo suuqa.
Marka la eego milanka, waxa loo qaybin karaa ionic iyo non-ionic.Ether-yada cellulose-ka aan-ionic-ka ee biyaha-milmi kara waxay inta badan ka kooban yihiin laba taxane ah oo ethers alkyl ah iyo ethers hydroxyalkyl.Ionic CMC waxaa inta badan loo isticmaalaa saabuunta synthetic, daabacaadda dunta iyo midabaynta, sahaminta cuntada iyo saliidda.Non-ionic MC, HPMC, HEMC, iwm. ayaa inta badan loo isticmaalaa qalabka dhismaha, daahan cinjirka ah, daawada, kiimikooyinka maalinlaha ah, iwm. Waxa loo isticmaalaa dhumuc weyn, wakiilka biyaha haynta, xasilinta, kala firdhiso iyo wakiilka samaynta filimada.
Haysashada biyaha ee ether cellulose: In wax soo saarka qalabka dhismaha, gaar ahaan dhoobada budada qalalan, ether cellulose waxay ka ciyaaraan door aan la bedeli karin, gaar ahaan soo saarista hoobiye gaar ah (hoobiye la bedelay), waa lagama maarmaan iyo qayb muhiim ah.Doorka muhiimka ah ee ether-ka cellulose-ka biyaha ku milma ee hoobiye wuxuu inta badan leeyahay saddex dhinac:
1. Awood biyo-hayn heer sare ah
2. Saamaynta joogtaynta hoobiye iyo thixotropy
3. Isdhexgalka sibidhka.
Saamaynta haynta biyaha ee ether cellulose waxay kuxirantahay nuugista biyaha ee lakabka saldhiga, ka kooban yahay hoobiye, dhumucda lakabka hoobiye, baahida biyaha ee hoobiye, iyo wakhtiga dejinta ee alaabta dejinta.Haysashada biyaha ee etherka cellulose lafteedu waxay ka timaadaa milanka iyo fuuq-baxa etherka cellulose laftiisa.Sida aynu wada ognahay, inkasta oo silsiladda unugyadu ay ka kooban tahay tiro badan oo ah kooxaha OH oo aad u fuuq-baxsan, kuma milmayaan biyaha, sababtoo ah qaab-dhismeedka cellulose wuxuu leeyahay heer sare oo crystallinity ah.Awoodda fuuq-celinta ee kooxaha hydroxyl oo keliya kuma filna inay daboosho curaarta hydrogen ee xooggan iyo xoogagga van der Waals ee u dhexeeya molecules.Sidaa darteed, kaliya way bararaan laakiin kuma milmaan biyaha.Marka beddelka lagu soo bandhigo silsiladda molecular, ma aha oo kaliya beddelka wuxuu baabi'iyaa silsiladda hydrogen, laakiin sidoo kale isku-xidhka hydrogen-ka interchain waa la burburiyaa sababtoo ah gogosha beddelka ee u dhexeeya silsiladaha ku xiga.Inta uu sii weynaado beddelka, ayaa sii weynaan doonta masaafada u dhaxaysa molecules.Masaafada weyn.Saamaynta weyn ee burburinta curaarta hydrogen, ether-ka cellulose wuxuu noqdaa mid biyo-milmi kara ka dib markii lakabka cellulose uu balaadhiyo oo xalku galo, samaynta xal sare oo viscosity ah.Marka heerkulku kordho, fuuq-baxa polymer-ka ayaa daciifa, biyaha u dhexeeya silsiladaha ayaa la saaraa.Marka saamaynta fuuqbaxa ay ku filan tahay, molecules-yadu waxay bilaabaan inay isugeeyaan, iyagoo samaynaya jel qaab-dhismeedka shabakad saddex-geesood ah oo laalaaban.
Waqtiga post: Dec-06-2022