IHydroxypropylmethylcellulose (HPMC) yikhompawundi ethe yaba sisiseko semathiriyeli ekrwada kumashishini amaninzi ngenxa yeempawu zayo ezininzi. Idla ngokusetyenziswa njengesongezo sokutya, isithambiso kwizinto zokuthambisa, kwaneseza zonyango kumayeza amaninzi. Ipropati ekhethekileyo ye-HPMC yindlela yokuziphatha ye-thixotropic, evumela ukuba iguqule i-viscosity kunye neempawu zokuhamba phantsi kweemeko ezithile. Ukongeza, zombini i-high-viscosity kunye ne-low-viscosity HPMC inale propati, ibonisa i-thixotropy nangaphantsi kobushushu bejeli.
Thixotropy yenzeka kwi-HPMC xa isisombululo siba yi-chear-thinning xa uxinzelelo lusetyenziswa okanye lushukunyiswa, okukhokelela ekunciphiseni kwe-viscosity. Oku kuziphatha nako kunokuguqulwa; xa uxinzelelo lususiwe kwaye isisombululo sishiywe ukuba siphumle, i-viscosity ibuyela ngokukhawuleza kwindawo yayo ephezulu. Le propati yahlukileyo yenza i-HPMC ibe licandelo elixabisekileyo kumashishini amaninzi njengoko ivumela usetyenziso olugudileyo kunye nokusebenza lula.
Njenge-nonionic hydrocolloid, i-HPMC idumba emanzini ukwenza ijeli. Iqondo lokuvuvukala kunye ne-gelling kuxhomekeke kubunzima be-molecular kunye nokugxininiswa kwepolymer, i-pH kunye nokushisa kwesisombululo. I-viscosity ephezulu ye-HPMC idla ngokuba nobunzima obuphezulu bemolekyuli kwaye ivelisa ijeli ye-viscosity ephezulu, ngelixa i-viscosity ephantsi i-HPMC inobunzima obuphantsi bemolekyuli kwaye ivelisa ijeli engabonakaliyo. Nangona kunjalo, ngaphandle kwalo mahluko ekusebenzeni, zombini iintlobo ze-HPMCs zibonisa i-thixotropy ngenxa yotshintsho lwesakhiwo olwenzeka kwinqanaba le-molecular.
Ukuziphatha kwe-thixotropic ye-HPMC sisiphumo sokulungelelaniswa kwamakhonkco e-polymer ngenxa yoxinzelelo lwe-shear. Xa uxinzelelo lwe-shear lusetyenziswa kwi-HPMC, iintambo ze-polymer zilungelelanisa kwicala loxinzelelo olusetyenzisiweyo, okukhokelela ekutshatyalalisweni kwesakhiwo sothungelwano lwe-dimensional emithathu ekhoyo ngokungabikho koxinzelelo. Ukuphazamiseka kwenethiwekhi kubangela ukuhla kwe-viscosity yesisombululo. Xa uxinzelelo lususiwe, amakhonkco e-polymer alungelelanisa ngokutsha kunye nokuqhelaniswa kwawo kwasekuqaleni, ukwakha kwakhona inethiwekhi kunye nokubuyisela i-viscosity.
I-HPMC iphinda ibonise i-thixotropy engaphantsi kobushushu be-gelling. Iqondo lobushushu lejeli liqondo lobushushu apho amatyathanga epolymer awela khona ukuze enze uthungelwano olunamacala amathathu, enze ijeli. Kuxhomekeke kugxininiso, ubunzima bemolekyuli kunye ne-pH yesisombululo sepolymer. I-gel ephumelayo ine-viscosity ephezulu kwaye ayitshintshi ngokukhawuleza phantsi koxinzelelo. Nangona kunjalo, ngaphantsi kobushushu be-gelation, isisombululo se-HPMC sahlala simanzi, kodwa sabonisa ukuziphatha kwe-thixotropic ngenxa yobukho besakhiwo sothungelwano esakhiwe ngokuyinxenye. Umnatha owenziwe ngala macandelo udiliza phantsi koxinzelelo, okubangela ukuhla kwe-viscosity. Oku kuziphatha kunenzuzo kwizicelo ezininzi apho izisombululo zifuna ukuhamba ngokulula xa zishukunyiswa.
I-HPMC yikhemikhali eguquguqukayo eneempawu ezininzi ezizodwa, enye yazo kukuziphatha kwayo kothixotropic. Zombini i-high-viscosity kunye ne-low-viscosity HPMCs zinale ndawo, ebonisa i-thixotropy nangaphantsi kobushushu bejeli. Olu phawu lwenza i-HPMC ibe licandelo elixabisekileyo kumashishini amaninzi afuna izisombululo ezibamba ukuhamba okulula ukuqinisekisa ukusetyenziswa okugudileyo. Nangona kukho umahluko kwiipropati phakathi kwe-high-viscosity kunye ne-low-viscosity HPMCs, ukuziphatha kwabo kwe-thixotropic kwenzeka ngenxa yokulungelelaniswa kunye nokuphazamiseka kwesakhiwo sothungelwano. Ngenxa yeempawu zayo ezizodwa, abaphandi bahlala bephonononga izicelo ezahlukeneyo ze-HPMC, benethemba lokudala iimveliso ezintsha kunye nokubonelela ngezisombululo ezingcono kubathengi kwihlabathi liphela.
Ixesha lokuposa: Aug-23-2023