I-cellulose ether yiklasi ebalulekileyo ye-polymer compounds, esetyenziswa ngokubanzi ekwakheni, amayeza, ukutya kunye nezinye iindawo. Phakathi kwabo, i-HPMC (i-hydroxypropyl methylcellulose), i-MC (i-methylcellulose), i-HEC (i-hydroxyethyl cellulose) kunye ne-CMC (i-carboxymethyl cellulose) zine-ethers ze-cellulose eziqhelekileyo.
I-Methyl cellulose (MC):
I-MC iyanyibilika emanzini abandayo kwaye kunzima ukuyinyibilika emanzini ashushu. Isisombululo samanzi sizinzile kakhulu kwi-pH = 3 ~ 12, sinokuhambelana kakuhle, kwaye sinokuxutywa kunye neentlobo ezahlukeneyo ze-surfactants ezifana nesitashi kunye ne-guar gum. Xa iqondo lokushisa lifikelela kwiqondo lokushisa, i-gelation iyenzeka.
Ukugcinwa kwamanzi kwe-MC kuxhomekeke kwisixa sokongeza, i-viscosity, i-particle fineness kunye nesantya sokuchithwa. Ngokuqhelekileyo, izinga lokugcinwa kwamanzi liphezulu xa inani elongezelelweyo likhulu, iinqununu zilungile kwaye i-viscosity iphezulu. Phakathi kwabo, isixa esongezelelweyo sinempembelelo enkulu kwizinga lokugcinwa kwamanzi, kwaye inqanaba le-viscosity alihambisani nesantya sokugcinwa kwamanzi. Isantya sokuchithwa sixhomekeke ikakhulu kwiqondo lokuguqulwa komphezulu kunye ne-particle fineness ye-cellulose particleness.
Utshintsho lobushushu luyakuchaphazela ngokumandla ugcino lwamanzi lweMC. Ngokuqhelekileyo, okukhona ubushushu buphezulu, kokukhona ukugcinwa kwamanzi kubi. Ukuba ubushushu bomdaka budlula i-40 ° C, ukugcinwa kwamanzi kwe-MC kuya kuncitshiswa kakhulu, kuchaphazela kakhulu ukusebenza kokwakhiwa kodaka.
I-MC inempembelelo ebalulekileyo ekusebenzeni kokwakhiwa kunye nokunamathela kodaka. Apha, "ukunamathela" kubhekisela ekunamatheleni phakathi kwezixhobo zokwakha zabasebenzi kunye ne-substrate eludongeni, oko kukuthi, ukuchasana kwe-shear yodaka. Okukhona ukuncamathela okukhulu, kokukhona ukuchetywa kodaka, amandla amakhulu afunwa ngumsebenzi ngexesha lokusetyenziswa, kunye nokusebenza kakubi kokwakhiwa kodaka. Ukunamathela kwe-MC kukwinqanaba eliphakathi phakathi kweemveliso ze-cellulose ether.
IHydroxypropyl methylcellulose (HPMC):
I-HPMC inyibilika ngokulula emanzini, kodwa kunokuba nzima ukuyinyibilikisa emanzini ashushu. Nangona kunjalo, ubushushu bayo be-gelation emanzini ashushu buphezulu kakhulu kune-MC, kwaye ukunyibilika kwayo kumanzi abandayo kukwangcono kune-MC.
I-viscosity ye-HPMC inxulumene nobunzima be-molecular, kwaye i-viscosity iphezulu xa ubunzima be-molecular bukhulu. Ubushushu buchaphazela i-viscosity yayo, kwaye i-viscosity iyancipha njengoko iqondo lokushisa lisanda, kodwa iqondo lokushisa apho i-viscosity yayo iyancipha ingaphantsi kune-MC. Isisombululo saso sizinzile kwiqondo lokushisa.
Ukugcinwa kwamanzi kwe-HPMC kuxhomekeke kwisixa esongezelelweyo kunye ne-viscosity, njl.
I-HPMC izinzile kwi-acids kunye ne-alkali, kwaye isisombululo sayo samanzi sizinzile kakhulu kwi-pH ye-2 ~ 12. I-Caustic soda kunye namanzi e-lime anempembelelo encinci ekusebenzeni kwayo, kodwa i-alkali inokukhawulezisa izinga lokuchithwa kwayo kunye nokwandisa i-viscosity. I-HPMC izinzile kwiityuwa ngokubanzi, kodwa xa uxinaniso lwesisombululo setyuwa luphezulu, i-viscosity yesisombululo se-HPMC ithande ukwanda.
I-HPMC inokuxutywa kunye neekhompawundi ze-polymer ezinyibilikayo emanzini ukwenza iyunifomu, isisombululo esiphezulu se-viscosity, njenge-polyvinyl alcohol, i-ether yesitatshi, i-gum yemifuno, njl.
I-HPMC inokumelana ne-enzayim engcono kune-MC, kwaye isisombululo sayo asichaphazeleki kancinci kukuwohloka kwe-enzymatic kune-MC. I-HPMC inoncanyathiso olungcono kudaka kune-MC.
Iselulosi yeHydroxyethyl (HEC):
I-HEC iyanyibilika emanzini abandayo kwaye kunzima ukuyinyibilika emanzini ashushu. Isisombululo sizinzile kwiqondo lokushisa eliphezulu kwaye asinazo iimpawu ze-gel. Ingasetyenziselwa udaka ixesha elide kwiqondo lokushisa eliphezulu, kodwa ukugcinwa kwayo kwamanzi kuphantsi kune-MC.
I-HEC izinzile kwi-acids jikelele kunye ne-alkali, i-alkali inokukhawulezisa ukuchithwa kwayo kunye nokunyusa kancinane i-viscosity, kunye ne-dispersibility yayo emanzini ingaphantsi kancinane kwi-MC kunye ne-HPMC.
I-HEC inokusebenza kakuhle kokunqunyanyiswa kodaka, kodwa isamente inexesha elide lokurhoxisa.
I-HEC eveliswe ngamanye amashishini asekhaya inokusebenza okuphantsi kune-MC ngenxa yomthamo wayo ophezulu wamanzi kunye nomxholo wothuthu.
Carboxymethyl cellulose (CMC):
I-CMC yi-ionic cellulose ether elungiswe luluhlu lwezonyango zokusabela emva kokuba imicu yendalo (efana nomqhaphu) iphathwe nge-alkali kunye ne-chloroacetic acid isetyenziswa njenge-etherifying agent. Iqondo lokutshintshwa ngokubanzi liphakathi kwe-0.4 kunye ne-1.4, kwaye ukusebenza kwayo kuchatshazelwa kakhulu ngumgangatho wokutshintshwa.
I-CMC ineempembelelo zokuqiniswa kunye ne-emulsification yokuzinzisa, kwaye ingasetyenziselwa iziselo eziqulethe ioli kunye neprotheni ukudlala indima yokuqinisa i-emulsification.
I-CMC inesiphumo sokugcina amanzi. Kwiimveliso zenyama, isonka, iibhanzi eziqhunyiweyo kunye nokunye ukutya, kunokudlala indima ekuphuculeni iithishu, kwaye kunokwenza amanzi angabinaguquguquki, anyuse isivuno semveliso, kwaye anyuse incasa.
I-CMC inefuthe le-gelling kwaye ingasetyenziselwa ukwenza ijeli kunye nejam.
I-CMC inokwenza ifilimu phezu kokutya, enempembelelo ethile yokukhusela kwiziqhamo kunye nemifuno kwaye yandisa ixesha leshelufu leziqhamo kunye nemifuno.
Ezi cellulose ethers nganye ineempawu zayo ezizodwa kunye neendawo zokusebenzisa. Ukukhethwa kweemveliso ezifanelekileyo kufuneka kumiselwe ngokweemfuno ezithile zesicelo kunye neemeko zokusingqongileyo.
Ixesha lokuposa: Oct-29-2024