Cellulose ether polymer roba ce da aka yi daga cellulose na halitta ta hanyar gyara sinadarai. Cellulose ether wani abu ne na cellulose na halitta. Samar da ether cellulose ya bambanta da polymers na roba. Mafi mahimmancin kayan sa shine cellulose, fili na polymer na halitta. Saboda ƙayyadaddun tsarin tsarin cellulose na halitta, cellulose kanta ba ta da ikon amsawa tare da ma'aikatan etherification. Koyaya, bayan maganin kumburin wakili, haɗin gwiwar hydrogen mai ƙarfi tsakanin sarƙoƙi na ƙwayoyin cuta da sarƙoƙi sun lalace, kuma sakin aiki na ƙungiyar hydroxyl ya zama alkali cellulose mai amsawa. Samun cellulose ether.
Abubuwan da ke cikin ethers cellulose sun dogara da nau'in, lamba da rarraba abubuwan maye. Rarraba ethers cellulose kuma yana dogara ne akan nau'in maye gurbin, digiri na etherification, solubility da abubuwan aikace-aikacen da suka danganci. Dangane da nau'in maye gurbin akan sarkar kwayoyin halitta, ana iya raba shi zuwa monoether da ether mai gauraye. Mu yawanci amfani da mc a matsayin monoether, da HPmc a matsayin gauraye ether. Methyl cellulose ether mc shine samfurin bayan ƙungiyar hydroxyl akan rukunin glucose na cellulose na halitta ya maye gurbin ƙungiyar methoxy. Samfuri ne da aka samu ta musanya wani ɓangare na ƙungiyar hydroxyl akan naúrar tare da ƙungiyar methoxy da wani ɓangaren tare da ƙungiyar hydroxypropyl. Tsarin tsari shine [C6H7O2 (OH) 3-mn (OCH3) m [OCH2CH (OH) CH3] n] x Hydroxyethyl methyl cellulose ether HEmc, waɗannan sune manyan nau'ikan da ake amfani da su kuma ana siyarwa a kasuwa.
Dangane da solubility, ana iya raba shi zuwa ionic da wadanda ba ionic ba. Ethers masu narkewar ruwa marasa ionic cellulose ethers galibi sun ƙunshi jerin ethers guda biyu na alkyl da ethers hydroxyalky. Ana amfani da Ionic Cmc galibi a cikin kayan wanka na roba, bugu da rini, abinci da binciken mai. Non-ionic mc, HPmc, HEmc, da dai sauransu ana amfani da su a cikin kayan gini, kayan kwalliyar latex, magani, sinadarai na yau da kullun, da sauransu. Ana amfani da su azaman thickener, mai riƙe ruwa, stabilizer, dispersant da wakili na samar da fim.
Riƙewar ruwa na ether cellulose
A cikin samar da kayan gini, musamman busassun turmi, ether cellulose yana taka rawar da ba za a iya maye gurbinsa ba, musamman wajen samar da turmi na musamman (turmi da aka gyaggyara), abu ne da ba dole ba ne kuma mai mahimmanci.
Muhimmin rawar da ruwa mai narkewa cellulose ether a turmi yafi yana da uku al'amurran, daya ne mai kyau ruwa rike iya aiki, da sauran shi ne tasiri a kan daidaito da thixotropy na turmi, kuma na uku shi ne hulda da ciminti.
Tasirin riƙewar ruwa na ether cellulose ya dogara ne akan shayar da ruwa na tushe mai tushe, abun da ke cikin turmi, kauri na turmi, buƙatar ruwa na turmi, da lokacin saitin kayan saiti. Riƙewar ruwa na ether cellulose kanta ya fito ne daga solubility da dehydration na cellulose ether kanta. Kamar yadda muka sani, duk da cewa sarkar kwayar halitta ta cellulose ta ƙunshi adadi mai yawa na ƙungiyoyin OH masu ɗorewa, ba mai narkewa cikin ruwa ba, saboda tsarin cellulose yana da babban matakin crystallinity. Ƙarfin hydration na ƙungiyoyin hydroxyl kadai bai isa ya rufe ƙaƙƙarfan haɗin hydrogen da van der Waals ba tsakanin kwayoyin halitta. Don haka sai kawai ta kumbura amma ba ta narke cikin ruwa. Lokacin da aka shigar da wanda zai maye gurbinsa a cikin sarkar kwayoyin halitta, ba kawai abin da zai maye gurbinsa yana lalata sarkar hydrogen ba, har ma da haɗin gwiwar hydrogen ɗin yana lalata saboda ƙulla abin da zai maye gurbin tsakanin sarƙoƙi da ke kusa. Girman abin da zai maye gurbin, mafi girman nisa tsakanin kwayoyin halitta. Mafi girman nisa. Mafi girman tasirin lalata haɗin gwiwar hydrogen, ether cellulose ya zama mai narkewar ruwa bayan ɗigon cellulose ya faɗaɗa kuma maganin ya shiga, yana samar da mafita mai zurfi. Lokacin da zafin jiki ya tashi, hydration na polymer ya raunana, kuma ana fitar da ruwa tsakanin sarƙoƙi. Lokacin da sakamakon rashin ruwa ya isa, kwayoyin sun fara haɗuwa, suna samar da gel ɗin tsarin cibiyar sadarwa mai girma uku kuma suna nannade waje. Abubuwan da suka shafi riƙewar ruwa na turmi sun haɗa da danko na ether cellulose, adadin da aka kara, da kyau na barbashi da yawan zafin jiki na amfani.
Mafi girman danko na ether cellulose, mafi kyawun aikin riƙewar ruwa, kuma mafi girman danko na maganin polymer. Dangane da nauyin kwayoyin halitta (digiri na polymerization) na polymer, an kuma ƙaddara shi ta hanyar tsayin sarkar tsarin kwayoyin halitta da siffar sarkar, kuma rarraba nau'o'in da yawa na masu maye gurbin shi ma yana tasiri kai tsaye ta danko. [η] = kmα
[η] Danko na ciki na maganin polymer
m polymer kwayoyin nauyi
α-polymer halayyar akai-akai
K danko bayani coefficient
Dankowar maganin polymer ya dogara da nauyin kwayoyin halitta na polymer. Danko da maida hankali na ether cellulose yana da alaƙa da aikace-aikacen a fannoni daban-daban. Saboda haka, kowane cellulose ether yana da yawa daban-daban danko bayani dalla-dalla, da kuma daidaita danko da aka yafi gane ta lalatar alkali cellulose, wato, karya na cellulose kwayoyin sarƙoƙi.
Mafi girman adadin ether cellulose da aka ƙara zuwa turmi, mafi kyawun aikin riƙewar ruwa, kuma mafi girman danko, mafi kyawun aikin riƙewar ruwa.
Don girman barbashi, mafi kyawun barbashi, mafi kyawun riƙewar ruwa (duba hoto 3). Bayan manyan barbashi na cellulose ether sun hadu da ruwa, nan da nan saman ya narke kuma ya samar da gel don kunsa kayan don hana kwayoyin ruwa daga ci gaba da shiga. Wani lokaci ba za a iya tarwatsewa da narkar da shi daidai ba ko da bayan dogon lokaci yana motsawa, yana samar da maganin flocculent mai hadari ko agglomeration. Yana tasiri sosai akan riƙe ruwa na ether cellulose, kuma solubility yana daya daga cikin abubuwan da za a zabi ether cellulose.
Thickening da Thixotropy na Cellulose Ether
Ayyukan na biyu na ether cellulose - thickening ya dogara da: digiri na polymerization na ether cellulose, maida hankali bayani, raguwa, zafin jiki da sauran yanayi. Kayan gelling na maganin ya keɓanta ga alkyl cellulose da abubuwan da aka gyara. Abubuwan gelation suna da alaƙa da matakin maye gurbin, ƙaddamar da bayani da ƙari. Don abubuwan da aka gyara na hydroxyalkyl, abubuwan gel ɗin kuma suna da alaƙa da canjin canjin hydroxyalkyl. Don mc da HPmc tare da ƙananan danko, 10% -15% maida hankali bayani za a iya shirya, 5% -10% bayani za a iya shirya don matsakaici danko mc da HPmc, da 2% -3% bayani za a iya shirya don high danko mc da HPmc, kuma yawanci Rabe-raben danko na cellulose ether shima ana yin sa da 1% -2% bayani. Maɗaukakin nauyin ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar cuta. A cikin bayani guda ɗaya, polymers tare da ma'aunin kwayoyin halitta daban-daban suna da danko daban-daban. Babban digiri. Maƙasudin danko kawai za a iya samu ta ƙara babban adadin ƙananan nauyin kwayar halitta ether. Dankowar sa yana da ɗan dogaro akan ƙimar juzu'i, kuma babban danko ya kai ga dankowar manufa, kuma adadin adadin da ake buƙata yana da ƙarami, kuma danko ya dogara da ƙimar girma. Sabili da haka, don cimma wani daidaituwa, dole ne a ba da garantin wani adadin ether cellulose (mahimmancin bayani) da danko bayani. Gel zafin jiki na maganin kuma yana raguwa a layi tare da karuwa da ƙaddamar da maganin, da gels a dakin da zafin jiki bayan kai wani taro. Matsakaicin gelation na HPmc ya fi girma a zafin jiki.
Hakanan za'a iya daidaita daidaito ta zabar girman barbashi da zabar ethers cellulose tare da digiri daban-daban na gyare-gyare. Abin da ake kira gyare-gyare shine gabatar da wani mataki na maye gurbin kungiyoyin hydroxyalkyl akan tsarin kwarangwal na mc. Ta hanyar canza dabi'un musanyawa na madogara biyun, wato, DS da ms dangi maye dabi'u na methoxy da hydroxyalkyl wadanda muke yawan fada. Ana iya samun buƙatun ayyuka daban-daban na ether cellulose ta hanyar canza dabi'un maye gurbin dangi na madogara biyu.
Cellulose ethers da aka yi amfani da su a cikin kayan gini na foda dole ne su narke da sauri a cikin ruwan sanyi kuma su samar da daidaito mai dacewa ga tsarin. Idan aka ba shi ƙayyadaddun ƙimar juzu'i, har yanzu yana zama flocculent kuma toshe colloidal, wanda ba shi da inganci ko ingancin samfur.
Har ila yau, akwai kyakkyawar dangantaka ta layi tsakanin daidaituwar simintin siminti da kuma adadin ether cellulose. Cellulose ether na iya ƙara dankowar turmi sosai. Girman adadin, mafi girman tasirin tasirin, duba Hoto 6
High-danko cellulose ether ruwa bayani yana da high thixotropy, wanda kuma shi ne babban hali na cellulose ether. Maganganun ruwa na nau'in polymers na Mc-type yawanci suna da pseudoplastic da ruwa maras-thixotropic a ƙasa da zafin gel ɗin su, amma kaddarorin kwararar Newtonian a ƙananan ƙimar ƙarfi. Pseudoplasticity yana ƙaruwa tare da nauyin kwayoyin halitta ko tattarawar ether cellulose, ba tare da la'akari da nau'in maye gurbin da matakin maye gurbin ba. Saboda haka, cellulose ethers na wannan danko sa, ko da mc, HPmc, HEmc, za su kullum nuna iri rheological Properties idan dai da taro da kuma yawan zafin jiki suna kiyaye akai. Ana samar da gels na tsari lokacin da zafin jiki ya tashi, kuma ana samun kwararar thixotropic sosai. Babban maida hankali da ƙananan danko ethers cellulose suna nuna thixotropy ko da a ƙasa da zafin jiki na gel. Wannan kadarar tana da fa'ida mai yawa ga daidaitawar daidaitawa da sagging a cikin ginin ginin turmi. Ya kamata a bayyana a nan cewa mafi girman danko na ether cellulose, mafi kyawun riƙewar ruwa, amma mafi girma da danko, mafi girman nauyin kwayoyin halitta na cellulose ether, da kuma raguwa mai dacewa a cikin solubility, wanda yana da mummunan tasiri. a kan turmi maida hankali da aikin yi. Mafi girma da danko, mafi bayyananne sakamako mai kauri akan turmi, amma bai dace ba. Wasu matsakaici da ƙananan danko, amma gyaggyarawa ether cellulose yana da mafi kyawun aiki wajen inganta ƙarfin tsarin jika. Tare da haɓakar danko, riƙewar ruwa na ether cellulose yana inganta.
Lokacin aikawa: Nuwamba-22-2022