I-Methylcellulose (MC)
Ifomula yemolekyuli ye-methylcellulose (MC) yile:
[C6H7O2(OH)3-h(OCH3)n\]x
Inkqubo yemveliso kukwenza i-cellulose ether ngokulandelelana kweempendulo emva kokuba umqhaphu ocociweyo uphathwe nge-alkali, kwaye i-methyl chloride isetyenziswa njenge-etherification agent. Ngokubanzi, inqanaba lokutshintshwa yi-1.6 ~ 2.0, kwaye ukunyibilika nako kwahlukile ngeqondo lokutshintshwa. Yeye-non-ionic cellulose ether.
I-Methylcellulose iyanyibilika emanzini abandayo, kwaye kuya kuba nzima ukuyinyibilikisa emanzini ashushu. Isisombululo sayo samanzi sizinzile kakhulu kuluhlu lwe-pH=3~12.
Ihambelana kakuhle nesitatshi, i-guar gum, njl.njl. kunye nezinye izinto ezininzi ezibangela ukuba i-surfactants ifikelele kubushushu be-gelation, i-gelation iyenzeka.
Ukugcinwa kwamanzi kwe-methylcellulose kuxhomekeke kubungakanani bayo bokongeza, i-viscosity, ubuncinci bee-particles kunye nesantya sokunyibilika.
Ngokubanzi, ukuba ubungakanani bokongeza bukhulu, ubuncinci bokutyeba, kwaye ubuncinci bokutyeba, izinga lokugcina amanzi liphezulu. Phakathi kwazo, ubungakanani bokongeza bunempembelelo enkulu kwizinga lokugcina amanzi, kwaye inqanaba lobuncinci alihambelani ngokuthe ngqo nenqanaba lokugcinwa kwamanzi. Inqanaba lokunyibilika lixhomekeke kakhulu kwinqanaba lokuguqulwa komphezulu wee-cellulose particles kunye nobuncinci be-particles.
Phakathi kwee-ethers ze-cellulose ezingentla, i-methyl cellulose kunye ne-hydroxypropyl methyl cellulose zinamazinga aphezulu okugcinwa kwamanzi.
I-Carboxymethylcellulose (CMC)
I-Carboxymethyl cellulose, ekwaziwa ngokuba yi-sodium carboxymethyl cellulose, eyaziwa ngokuba yi-cellulose, cmc, njl.njl., yi-anionic linear polymer, ityuwa yesodium ye-cellulose carboxylate, kwaye ihlaziyeka kwaye ayitshi. Izinto ezikrwada zekhemikhali.
Isetyenziswa kakhulu kwishishini lesepha, kwishishini lokutya nakwi-oyile, kwaye isixa esisetyenziswa kwizithambiso simalunga ne-1% kuphela.
I-ether ye-ionic cellulose yenziwe ngeefayibha zendalo (ikotoni, njl.njl.) emva konyango lwe-alkali, kusetyenziswa i-sodium monochloroacetate njenge-etherification agent, kwaye ifumana uthotho lweendlela zonyango lokuphendula.
Iqondo lokutshintshwa ngokubanzi liyi-0.4 ~ 1.4, kwaye ukusebenza kwayo kuchaphazeleka kakhulu liqondo lokutshintshwa.
I-CMC inamandla okubopha kakuhle, kwaye isisombululo sayo samanzi sinamandla okuxhoma, kodwa akukho xabiso lokwenyani lokuguqulwa kweplastiki.
Xa i-CMC inyibilika, i-depolymerization iyenzeka ngokwenene. I-viscosity iqala ukunyuka ngexesha lokunyibilika, idlule kwi-maximum, ize yehle iye kwi-plateau. I-viscosity ephumayo inxulumene ne-depolymerization.
Ubungakanani bokunyibilika kwe-polymerization bunxulumene ngokusondeleyo nobungakanani be-solvent engalunganga (amanzi) kwifomyula. Kwinkqubo yokunyibilika engalunganga, njenge-toothpaste equlethe i-glycerin namanzi, i-CMC ayizukunyibilika ngokupheleleyo kwaye iya kufikelela kwinqanaba lokulingana.
Kwimeko yoxinzelelo lwamanzi oluthile, i-CMC ethatyathwe kakhulu ngamanzi kulula ukuyisusa ipolymeri kune-CMC ethatyathwe kancinci.
I-Hydroxyethylcellulose (HEC)
I-HEC yenziwa ngokunyanga umqhaphu ocoliweyo nge-alkali, ize emva koko ixutywe ne-ethylene oxide njenge-etherification agent xa kukho i-acetone. Ubungakanani bokutshintshwa kwayo ngokubanzi yi-1.5 ~ 2.0. Inamandla okuthanda ukufuma kwaye kulula ukufunxa umswakama.
I-Hydroxyethyl cellulose iyanyibilika emanzini abandayo, kodwa kunzima ukuyinyibilikisa emanzini ashushu. Isisombululo sayo sizinzile kubushushu obuphezulu ngaphandle kokufaka ijeli.
Izinzile kwiiasidi eziqhelekileyo kunye neziseko. Ii-alkalis zinokukhawulezisa ukunyibilika kwayo kwaye zonyuse kancinci i-viscosity yayo. Ukusasazeka kwayo emanzini kubi kancinci kunokwe-methyl cellulose kunye ne-hydroxypropyl methyl cellulose.
IHydroxypropyl Methyl Cellulose (HPMC)
Ifomula yemolekyuli ye-HPMC yile:
\[C6H7O2(OH)3-mn(OCH3)m,OCH2CH(OH)CH3\]n\]x
I-Hydroxypropyl methylcellulose luhlobo lwe-cellulose oluphuma kuyo kwaye lusetyenziswa ngokukhawuleza.
Yi-ether exutyiweyo ye-non-ionic cellulose eyenziwe ngekotoni ecociweyo emva kokwenziwa kwe-alkali, isebenzisa i-propylene oxide kunye ne-methyl chloride njenge-etherification agent, ngokusebenzisa uthotho lweempendulo. Umlinganiselo wokutshintshwa ngokubanzi yi-1.2 ~ 2.0.
Iimpawu zayo zahlukile ngenxa yomlinganiselo owahlukileyo womxholo we-methoxyl kunye nomxholo we-hydroxypropyl.
I-hydroxypropyl methylcellulose inyibilika lula emanzini abandayo, kodwa iya kujongana nobunzima bokunyibilika emanzini ashushu. Kodwa ubushushu bayo be-gelation emanzini ashushu buphezulu kakhulu kunobo be-methyl cellulose. Ukunyibilika emanzini abandayo nako kuphucuke kakhulu xa kuthelekiswa ne-methyl cellulose.
Ubunzima be-hydroxypropyl methylcellulose bunxulumene nobunzima bayo beemolekyuli, kwaye okukhona ubunzima be-molekyuli bukhulu, kokukhona ubuninzi be-viscosity buphezulu. Ubushushu bukwachaphazela nobunzima bayo, njengoko ubushushu busanda, ubuninzi be-viscosity buyehla. Nangona kunjalo, ubuninzi be-viscosity yayo bunefuthe eliphantsi lobushushu kune-methyl cellulose. Isisombululo sayo sizinzile xa sigcinwe kubushushu begumbi.
Ukugcinwa kwamanzi kwe-hydroxypropyl methylcellulose kuxhomekeke kubungakanani bayo bokongeza, i-viscosity, njl.njl., kwaye izinga layo lokugcinwa kwamanzi kwinani elifanayo lokongeza liphezulu kunele-methyl cellulose.
I-Hydroxypropyl methylcellulose izinzile kwi-asidi kunye ne-alkali, kwaye isisombululo sayo samanzi sizinzile kakhulu kuluhlu lwe-pH=2~12. I-Caustic soda kunye namanzi ekalika azinampembelelo ingako ekusebenzeni kwayo, kodwa i-alkali inokukhawulezisa ukunyibilika kwayo kwaye yonyuse i-viscosity yayo.
I-hydroxypropyl methylcellulose izinzile kwiityuwa eziqhelekileyo, kodwa xa uxinzelelo lwesisombululo setyuwa luphezulu, i-viscosity yesisombululo se-hydroxypropyl methylcellulose idla ngokwanda.
I-hydroxypropyl methylcellulose ingaxutywa nee-polymer compounds ezinyibilikayo emanzini ukuze zenze isisombululo esifanayo nesinoburhabaxa obuphezulu. Ezifana ne-polyvinyl alcohol, i-starch ether, i-vegetable gum, njl.
I-hydroxypropyl methylcellulose inokumelana okungcono kwee-enzyme kune-methylcellulose, kwaye isisombululo sayo asinakwenzeka ukuba siwohloke ngokwe-enzyme kune-methylcellulose.
Ixesha lokuthumela: Februwari-14-2023