IHydroxypropyl Methylcellulose (HPMC) iwukuphuma kwe-cellulose ether okubalulekile osekusetshenziswe kabanzi emikhakheni eminingi yezimboni ngenxa yezakhiwo zayo eziyingqayizivele zomzimba namakhemikhali. Izakhiwo zayo ze-viscosity zingenye yezakhiwo ezibaluleke kakhulu ze-HPMC, ezithinta ngqo ukusebenza kwayo ezinhlelweni ezihlukahlukene.
1. Izakhiwo eziyisisekelo ze-HPMC
I-HPMC i-nonionic cellulose ether etholwe ngokufaka esikhundleni ingxenye yamaqembu e-hydroxyl (–OH) ku-molecule ye-cellulose ngamaqembu e-methoxy (–OCH3) namaqembu e-hydroxypropyl (–OCH2CH(OH) CH3). Inoncibilika kahle emanzini nakwezinye izincibilikisi eziphilayo, zakha izixazululo ze-colloidal ezisobala. I-viscosity ye-HPMC inqunywa ikakhulukazi isisindo sayo se-molecular, degree of substitution (DS, Degree of Substitution) kanye nokusatshalaliswa okuhlukile.
2. Ukunqunywa kwe-viscosity ye-HPMC
I-viscosity yezixazululo ze-HPMC ngokuvamile ikalwa kusetshenziswa i-viscometer ejikelezayo noma i-capillary viscometer. Lapho ukala, ukunakwa kufanele kukhokhwe ekugxilweni, izinga lokushisa kanye nesilinganiso se-shear sesisombululo, njengoba lezi zici zingathinta kakhulu inani le-viscosity.
Ukugxila kwesixazululo: I-viscosity ye-HPMC iyanda ngokukhula kokugxila kwesixazululo. Uma ukugxila kwesisombululo se-HPMC kuphansi, ukusebenzisana phakathi kwama-molecule kuba buthakathaka futhi i-viscosity iphansi. Njengoba ukugxila kukhula, ukubopha nokusebenzisana phakathi kwama-molecule kuyanda, okubangela ukwanda okukhulu kwe-viscosity.
Izinga lokushisa: I-viscosity yezixazululo ze-HPMC izwela kakhulu izinga lokushisa. Ngokuvamile, njengoba izinga lokushisa likhuphuka, i-viscosity yesisombululo se-HPMC izokwehla. Lokhu kungenxa yokwanda kwezinga lokushisa okuholela ekwandeni kokunyakaza kwamangqamuzana kanye nokwenza buthaka ukusebenzisana kwama-intermolecular. Kumele kuqashelwe ukuthi i-HPMC enamazinga ahlukene wokushintsha kanye nesisindo samangqamuzana anokuzwela okuhlukile ekushiseni.
Izinga le-Shear: Izixazululo ze-HPMC zibonisa ukuziphatha kwe-pseudoplastic (shear thinning), okungukuthi i-viscosity iphezulu ngamazinga aphansi okugunda futhi yehla ngamanani aphezulu okugunda. Lokhu kuziphatha kungenxa yamandla okugunda aqondanisa amaketanga amangqamuzana eduze kokuqondisa kwe-shear, ngaleyo ndlela anciphise ukubopha kanye nokusebenzisana phakathi kwama-molecule.
3. Izinto ezithinta i-HPMC viscosity
Isisindo samangqamuzana: Isisindo samangqamuzana e-HPMC singenye yezinto ezibalulekile ezinquma i-viscosity yayo. Ngokuvamile, lapho isisindo samangqamuzana sikhulu, siphakamisa i-viscosity yesisombululo. Lokhu kungenxa yokuthi ama-molecule e-HPMC anesisindo samangqamuzana aphezulu maningi amathuba okuthi enze amanethiwekhi abambene, ngaleyo ndlela andise ukungqubuzana kwangaphakathi kwesixazululo.
Izinga lokushintshwa kanye nokusatshalaliswa okuhlukile: Inombolo nokusatshalaliswa kwama-methoxy kanye ne-hydroxypropyl esikhundleni ku-HPMC nakho kuthinta i-viscosity yayo. Ngokuvamile, ukuphakama kwedigri ye-methoxy substitution (DS), i-viscosity ye-HPMC yehla, ngoba ukwethulwa kwama-substituent e-methoxy kuzonciphisa amandla okubopha i-hydrogen phakathi kwama-molecule. Ukwethulwa kwama-substituents e-hydroxypropyl kuzokwandisa ukusebenzisana kwama-intermolecular, ngaleyo ndlela kwandise i-viscosity. Ngaphezu kwalokho, ukusatshalaliswa okufanayo kwama-substituents kusiza ukwakha uhlelo oluzinzile lwesisombululo nokwandisa i-viscosity yesisombululo.
Inani le-pH lesixazululo: Nakuba i-HPMC iyi-polymer engeyona i-ionic futhi i-viscosity yayo ayizwani nezinguquko zenani le-pH yesisombululo, amanani e-pH edlulele (ane-acidic kakhulu noma ane-alkaline kakhulu) angase abangele ukuwohloka kwesakhiwo samangqamuzana egazi. I-HPMC, ngaleyo ndlela ithinta i-viscosity.
4. Izinkambu zokufaka izicelo ze-HPMC
Ngenxa yezici zayo ezinhle kakhulu ze-viscosity, i-HPMC isetshenziswa kabanzi emikhakheni eminingi:
Izinto zokwakha: Ezintweni zokwakha, i-HPMC isetshenziswa njenge-ejenti yokuqina kanye ne-ejenti yokugcina amanzi ukuze kuthuthukiswe ukusebenza komsebenzi wokwakha nokwandisa ukumelana nokuqhekeka.
Imboni yezemithi: Embonini yezemithi, i-HPMC isetshenziswa njengesihlanganisi samaphilisi, i-ejenti eyenza ifilimu yamaphilisi kanye nesithwali semithi ekhishwa isikhathi eside.
Imboni yokudla: I-HPMC isetshenziswa njenge-thickener ne-stabilizer embonini yokudla ukuze kukhiqizwe u-ayisikhilimu, ujeli kanye nemikhiqizo yobisi.
Imikhiqizo yamakhemikhali yansuku zonke: Emikhiqizweni yamakhemikhali yansuku zonke, i-HPMC isetshenziswa njenge-thickener ne-stabilizer ukukhiqizwa kwe-shampoo, ijeli yokugeza, umuthi wokuxubha, njll.
Izici ze-viscosity ze-HPMC ziyisisekelo sokusebenza kwayo okuhle kakhulu ezinhlelweni ezahlukahlukene. Ngokulawula isisindo samangqamuzana, izinga lokushintsha, nezimo zesixazululo ze-HPMC, i-viscosity yayo ingalungiswa ukuze ihlangabezane nezidingo ezihlukene zohlelo lokusebenza. Ngokuzayo, ucwaningo olujulile ngobudlelwano phakathi kwesakhiwo samangqamuzana e-HPMC kanye ne-viscosity luzosiza ukuthuthukisa imikhiqizo ye-HPMC ngokusebenza okungcono futhi kwandise izinkambu zayo zokusebenza.
Isikhathi sokuthumela: Jul-20-2024