IHydroxypropylmethylcellulose (HPMC) yikhompawundi eye yaba yinto eqhelekileyo kwimizi-mveliso emininzi ngenxa yeempawu zayo ezininzi zokusebenza. Isetyenziswa kakhulu njengesongezo sokutya, isithambisi kwizinto zokuthambisa, kwanesithako sezonyango kumayeza amaninzi. Ipropati eyahlukileyo yeHPMC yindlela yayo yokwenza izinto zethixotropic, evumela ukuba itshintshe iimpawu ze-viscosity kunye nokuhamba kwamanzi phantsi kweemeko ezithile. Ukongeza, zombini i-HPMC ene-viscosity ephezulu kunye ne-viscosity ephantsi inale propati, ibonisa i-thixotropy nangaphantsi kobushushu bejeli.
I-Thixotropy yenzeka kwi-HPMC xa isisombululo siba sincinci xa uxinzelelo lufakwa okanye luxutywa, nto leyo ebangela ukuncipha kwe-viscosity. Le ndlela yokuziphatha inokuguqulwa; xa uxinzelelo lususiwe kwaye isisombululo sishiywe ukuba siphumle, i-viscosity ibuyela kancinci kwimeko yayo ephezulu. Le propati ikhethekileyo yenza i-HPMC ibe yinxalenye ebalulekileyo kumashishini amaninzi njengoko ivumela ukusetyenziswa okuthambileyo kunye nokucutshungulwa okulula.
Njenge-hydrocolloid engeyiyo i-ionic, i-HPMC iyadumba emanzini ukuze yenze ijeli. Ubungakanani bokudumba kunye ne-gelling buxhomekeke kubunzima be-molecular kunye noxinzelelo lwe-polymer, i-pH kunye nobushushu besisombululo. I-HPMC ene-viscosity ephezulu idla ngokuba nobunzima be-molecular ephezulu kwaye ivelisa ijeli ene-viscosity ephezulu, ngelixa i-viscosity ephantsi i-HPMC inobunzima be-molecular obuphantsi kwaye ivelisa ijeli ene-viscous encinci. Nangona kunjalo, nangona la mahluko ekusebenzeni, zombini ezi ntlobo ze-HPMC zibonisa i-thixotropy ngenxa yotshintsho lwesakhiwo olwenzeka kwinqanaba le-molecular.
Ukuziphatha kwe-thixotropic kwe-HPMC kubangelwa kukulungelelaniswa kweetyathanga zepolymer ngenxa yoxinzelelo lwe-shear. Xa uxinzelelo lwe-shear lusetyenziswa kwi-HPMC, iityathanga zepolymer zihambelana kwicala loxinzelelo olusetyenzisiweyo, nto leyo ebangela ukutshatyalaliswa kwesakhiwo senethiwekhi esinemilinganiselo emithathu esasikho xa kungekho xinzelelo. Ukuphazamiseka kwenethiwekhi kubangela ukwehla kwe-viscosity yesisombululo. Xa uxinzelelo lususiwe, iityathanga zepolymer zihlengahlengiswa ngokwendlela ezaziqheleke ngayo ekuqaleni, zakha inethiwekhi kwaye zabuyisela i-viscosity.
I-HPMC ikwabonisa i-thixotropy ngaphantsi kobushushu be-gelling. Ubushushu be-gel bubushushu apho ii-polymer zidibana khona ukuze zenze inethiwekhi enemilinganiselo emithathu, zenze i-gel. Kuxhomekeke kuxinzelelo, ubunzima be-molecular kunye ne-pH yesisombululo se-polymer. I-gel ephumayo ine-viscosity ephezulu kwaye ayitshintshi ngokukhawuleza phantsi koxinzelelo. Nangona kunjalo, ngaphantsi kobushushu be-gelation, isisombululo se-HPMC sahlala singamanzi, kodwa sisabonisa ukuziphatha kwe-thixotropic ngenxa yokubakho kwesakhiwo senethiwekhi esakhiwe kancinci. Inethiwekhi eyenziwe ngala macandelo iyawohloka phantsi koxinzelelo, nto leyo ebangela ukwehla kwe-viscosity. Olu hlobo lokuziphatha luluncedo kwiindawo ezininzi apho izisombululo kufuneka zihambe ngokulula xa zixutywa.
I-HPMC yikhemikhali eguquguqukayo eneempawu ezahlukeneyo, enye yazo yindlela yayo yokwenza izinto ye-thixotropic. Zombini ii-HPMC ezinobukrakra obuphezulu kunye nobunzima obuphantsi zineempawu ezinjalo, zibonisa i-thixotropy nangaphantsi kobushushu bejeli. Olu phawu lwenza i-HPMC ibe yinxalenye ebalulekileyo kumashishini amaninzi afuna izisombululo ezisingatha ukuhamba okulula ukuqinisekisa ukusetyenziswa kakuhle. Nangona kukho umahluko kwiipropati phakathi kwee-HPMC ezinobukrakra obuphezulu kunye nobunzima obuphantsi, ukuziphatha kwazo kwe-thixotropic kwenzeka ngenxa yokulungelelaniswa kunye nokuphazamiseka kwesakhiwo senethiwekhi esakhiwe kancinci. Ngenxa yeempawu zayo ezizodwa, abaphandi bahlala behlola usetyenziso olwahlukeneyo lwe-HPMC, benethemba lokwenza iimveliso ezintsha kunye nokubonelela ngezisombululo ezingcono kubathengi kwihlabathi liphela.
Ixesha lokuthumela: Agasti-23-2023