I-Hydroxypropyl methylcellulose (HPMC) yi-polymer enyibilikayo emanzini engeyiyo i-ionic efunyenwe ngokuguqulwa kweekhemikhali ze-cellulose yendalo. Isetyenziswa kakhulu kumashishini okutya, amayeza, izinto zokuthambisa kunye nokwakha, ngakumbi njenge-adhesive, i-thickener, i-emulsifier kunye ne-suspending agent kumalungiselelo amayeza. Kwinkqubo yokufaka, iimpawu ze-viscosity zesisombululo samanzi se-HPMC zibalulekile ekusebenzeni kwaso kwiinkalo ezahlukeneyo.
1. Ulwakhiwo kunye neempawu ze-hydroxypropyl methylcellulose
Ulwakhiwo lwemolekyuli ye-HPMC luqulathe amaqela amabini athatha indawo, i-hydroxypropyl (-CH2)₂I-CHOHCH₃kunye ne-methyl (-OCH₃), nto leyo eyenza ukuba ibe nokunyibilika kakuhle kwamanzi kunye nokukwazi ukuguqula. Ikhonkco le-molecular ye-HPMC linesakhiwo esithile esiqinileyo, kodwa linokwenza nesakhiwo senethiwekhi esinemilinganiselo emithathu kwisisombululo samanzi, nto leyo ebangela ukwanda kwe-viscosity. Ubunzima bayo be-molecular, uhlobo lwe-substituent kunye nenqanaba lokutshintsha (oko kukuthi, inqanaba le-hydroxypropyl kunye ne-methyl substitution yeyunithi nganye) zinempembelelo ebalulekileyo kwi-viscosity yesisombululo.
2. Iimpawu zokuxinana kwesisombululo samanzi
Iimpawu ze-viscosity zesisombululo samanzi se-HPMC zinxulumene kakhulu nezinto ezifana noxinzelelo, ubunzima beemolekyuli, ubushushu kunye nexabiso le-pH yesinyibilikisi. Ngokubanzi, i-viscosity yesisombululo samanzi se-HPMC iyanda ngokunyuka koxinzelelo lwayo. I-viscosity yayo ibonisa ukuziphatha kwe-rheological okungengokwaseNewtonian, oko kukuthi, njengoko izinga lokucheba lisanda, i-viscosity yesisombululo iyancipha kancinci kancinci, ibonisa into yokuba i-shear thinning.
(1) Isiphumo sokugxila
Kukho ubudlelwane obuthile phakathi kwe-viscosity yesisombululo samanzi se-HPMC kunye noxinzelelo lwayo. Njengoko uxinzelelo lwe-HPMC lusanda, ukusebenzisana kweemolekyuli kwisisombululo samanzi kuyaphucuka, kwaye ukuxinana kunye nokudibanisa ii-molecular chains kuyanda, okubangela ukwanda kwe-viscosity yesisombululo. Kwi-concentrations ephantsi, i-viscosity yesisombululo samanzi se-HPMC iyanda ngokuthe ngqo ngokunyuka kwe-concentration, kodwa kwi-concentrations ephezulu, ukukhula kwe-viscosity yesisombululo kudla ngokuba tyaba kwaye kufikelele kwixabiso elizinzileyo.
(2) Isiphumo sobunzima bemolekyuli
Ubunzima bemolekyuli ye-HPMC buchaphazela ngokuthe ngqo i-viscosity yesisombululo sayo samanzi. I-HPMC enobunzima bemolekyuli obuphezulu ineemixokelelwane zemolekyuli ezinde kwaye inokwenza isakhiwo senethiwekhi esintsonkothileyo esinemilinganiselo emithathu kwisisombululo samanzi, nto leyo ebangela i-viscosity ephezulu. Ngokwahlukileyo koko, i-HPMC enobunzima bemolekyuli obuphantsi inesakhiwo senethiwekhi esikhululekileyo kunye ne-viscosity ephantsi ngenxa yeemixokelelwane zayo zemolekyuli ezimfutshane. Ke ngoko, xa ufaka, kubaluleke kakhulu ukukhetha i-HPMC enobunzima bemolekyuli obufanelekileyo ukuze ufezekise isiphumo se-viscosity esifanelekileyo.
(3) Isiphumo sobushushu
Ubushushu buyinto ebalulekileyo echaphazela ukuxinana kwesisombululo samanzi se-HPMC. Njengoko ubushushu busanda, intshukumo yeemolekyuli zamanzi iyaqina kwaye ukuxinana kwesisombululo kudla ngokuncipha. Oku kungenxa yokuba xa ubushushu bunyuka, inkululeko yetsheyini yeemolekyuli ze-HPMC iyanda kwaye ukusebenzisana phakathi kweemolekyuli kuyabuthathaka, ngaloo ndlela kunciphisa ukuxinana kwesisombululo. Nangona kunjalo, impendulo ye-HPMC evela kwiibhetshi ezahlukeneyo okanye kwiimpawu zobushushu nayo inokwahluka, ngoko ke iimeko zobushushu kufuneka zilungiswe ngokweemfuno ezithile zokusetyenziswa.
(4) Isiphumo sexabiso le-pH
I-HPMC ngokwayo yikhompawundi engeyiyo i-ionic, kwaye i-viscosity yesisombululo sayo samanzi inovelwano kutshintsho kwi-pH. Nangona i-HPMC ibonisa iimpawu ze-viscosity ezizinzileyo kwiindawo ezine-acid okanye ezingathathi cala, ukunyibilika kunye ne-viscosity ye-HPMC kuya kuchaphazela kwiindawo ezine-acid okanye ezine-alkaline kakhulu. Umzekelo, phantsi kweemeko ze-acid enamandla okanye ezine-alkaline enamandla, iimolekyuli ze-HPMC zinokonakala kancinci, ngaloo ndlela zinciphisa i-viscosity yesisombululo sayo samanzi.
3. Uhlalutyo lwe-Rheological lweempawu ze-viscosity zesisombululo samanzi se-HPMC
Indlela esebenza ngayo i-rheological yesisombululo samanzi se-HPMC idla ngokubonisa iimpawu zolwelo olungelulo lwe-Newtonian, nto leyo ethetha ukuba i-viscosity yayo ayinxulunyaniswanga nje kuphela nezinto ezifana noxinzelelo lwesisombululo kunye nobunzima be-molecular, kodwa ikwanxulumene nesantya sokucheba. Ngokubanzi, kwizinga eliphantsi lokucheba, isisombululo samanzi se-HPMC sibonisa i-viscosity ephezulu, ngelixa njengoko izinga lokucheba lisanda, i-viscosity iyancipha. Le ndlela yokuziphatha ibizwa ngokuba yi-"shear thinning" okanye "shear thinning" kwaye ibaluleke kakhulu kwizicelo ezininzi ezisebenzayo. Umzekelo, kwicandelo lokugquma, amalungiselelo amayeza, ukucutshungulwa kokutya, njl.njl., iimpawu ze-shear thinning ze-HPMC zinokuqinisekisa ukuba i-viscosity ephezulu igcinwa ngexesha lokusetyenziswa kwesantya esiphantsi, kwaye inokugeleza lula phantsi kweemeko ze-shear yesantya esiphezulu.
4. Ezinye izinto ezichaphazela i-viscosity yesisombululo samanzi se-HPMC
(1) Isiphumo setyuwa
Ukongezwa kwezinto ezinyibilikisa ityuwa (ezifana ne-sodium chloride) kunokunyusa i-viscosity yesisombululo samanzi se-HPMC. Oku kungenxa yokuba ityuwa inokuphucula ukusebenzisana phakathi kwee-molecules ngokutshintsha amandla e-ionic esisombululo, ukuze ii-molecules ze-HPMC zenze isakhiwo senethiwekhi esincinci ngakumbi, ngaloo ndlela sandisa i-viscosity. Nangona kunjalo, impembelelo yohlobo lwetyuwa kunye noxinzelelo kwi-viscosity nayo kufuneka ilungiswe ngokweemeko ezithile.
(2) Isiphumo sezinye izongezo
Ukongeza ezinye izongezo (ezifana nee-surfactants, ii-polymers, njl.njl.) kwisisombululo samanzi se-HPMC kuya kuchaphazela i-viscosity. Umzekelo, ii-surfactants zinokunciphisa i-viscosity ye-HPMC, ingakumbi xa uxinzelelo lwe-surfactant luphezulu. Ukongeza, ii-polymers okanye amasuntswana athile anokusebenzisana ne-HPMC kwaye atshintshe iimpawu ze-rheological zesisombululo sayo.
Iimpawu ze-viscosityi-hydroxypropyl methylcellulose Isisombululo samanzi sichaphazeleka zizinto ezininzi, kuquka uxinaniso, ubunzima beemolekyuli, ubushushu, ixabiso le-pH, njl. Isisombululo samanzi se-HPMC sidla ngokubonisa iipropati ze-rheological ezingezizo eze-Newtonian, sineempawu ezilungileyo zokutyeba kunye nokucheba, kwaye sisetyenziswa kakhulu kwiindawo ezahlukeneyo zoshishino kunye nezamayeza. Ukuqonda kunye nokuqonda ezi mpawu ze-viscosity kuya kunceda ukuphucula ukusetyenziswa kwe-HPMC kwizicelo ezahlukeneyo. Kwizicelo ezisebenzayo, uhlobo olufanelekileyo lwe-HPMC kunye neemeko zenkqubo kufuneka zikhethwe ngokweemfuno ezithile ukuze kufunyanwe iipropati ze-viscosity kunye ne-rheological ezifanelekileyo.
Ixesha leposi: Matshi-01-2025