IHydroxyethylcellulose (HEC) iyi-polymer encibilika emanzini evame ukusetshenziswa embonini nasocwaningweni lwesayensi. Isetshenziswa kakhulu njenge-thickener, i-ejenti eyenza ifilimu, i-adhesive, emulsifier kanye ne-stabilizer.
Izakhiwo eziyisisekelo ze-HEC
I-HEC iyi-polymer engeyona i-ionic encibilika emanzini, i-hydroxyethylated derivative etholakala ku-cellulose ngokusabela kwe-ethylation. Ngenxa yemvelo yayo engeyona i-ionic, ukuziphatha kwe-HEC esixazululweni ngokuvamile akushintshwa kakhulu yi-pH yesisombululo. Ngokuphambene, ama-polymer amaningi e-ionic (afana ne-sodium polyacrylate noma ama-carbomers) azwela kakhulu ku-pH ngoba isimo sawo sokushaja siyashintsha ngokushintsha kwe-pH, okuthinta ukunyibilika nokujiya kwawo. ukusebenza nezinye izakhiwo.
Ukusebenza kwe-HEC ngamavelu e-pH ahlukene
I-HEC ngokuvamile inozinzo oluhle ngaphansi kwezimo ezine-asidi ne-alkaline. Ngokukhethekile, i-HEC ingagcina i-viscosity yayo kanye nezakhiwo ezishubile endaweni ebanzi ye-pH. Ucwaningo lubonisa ukuthi i-viscosity nekhono lokujiya le-HEC lizinzile ngokuqhathaniswa phakathi kwebanga le-pH lika-3 kuya ku-12. Lokhu kwenza i-HEC ibe ukuqina nezimo eziguquguqukayo ngokwedlulele ezinhlelweni eziningi zezimboni futhi ingasetshenziswa ngaphansi kwezimo ze-pH ezihlukene.
Nokho, ukuzinza kwe-HEC kungase kuthinteke ngamavelu e-pH eyeqisayo (njenge-pH engaphansi kuka-2 noma ngaphezulu kuka-13). Ngaphansi kwalezi zimo, amaketanga amangqamuzana e-HEC angase abhekane ne-hydrolysis noma ukuwohloka, okuholela ekunciphiseni kwe-viscosity yayo noma izinguquko ezindaweni zayo. Ngakho-ke, ukusetshenziswa kwe-HEC ngaphansi kwalezi zimo ezimbi kakhulu kudinga ukunakwa okukhethekile ekuzinzeni kwayo.
Ukucatshangelwa kwesicelo
Ezisetshenziswa ezingokoqobo, ukuzwela kwe-pH ye-HEC kuphinde kuhlobane nezinye izici, njengezinga lokushisa, amandla e-ionic, kanye ne-polarity ye-solvent. Kwezinye izinhlelo zokusebenza, nakuba izinguquko ze-pH zinomthelela omncane ku-HEC, ezinye izici zemvelo zingase zikhulise lo mphumela. Isibonelo, ngaphansi kwezimo zokushisa eziphakeme, amaketanga e-HEC amangqamuzana angase akhiqize i-hydrolyze ngokushesha, ngaleyo ndlela abe nomthelela omkhulu ekusebenzeni kwawo.
Ngaphezu kwalokho, kwezinye izimo, njengama-emulsions, ama-gel kanye nama-coatings, i-HEC ivame ukusetshenziswa kanye nezinye izithako (njengama-surfactants, usawoti noma izilawuli ze-acid-base). Kuleli qophelo, nakuba i-HEC ingazweli ku-pH ngokwayo, lezi ezinye izingxenye zingathinta ngokungaqondile ukusebenza kwe-HEC ngokushintsha i-pH. Isibonelo, isimo sokushaja samanye ama-surfactants siyashintsha ngamavelu e-pH ahlukene, angase athinte ukuxhumana phakathi kwe-HEC nama-surfactants, ngaleyo ndlela aguqule izakhiwo ze-rheological zesisombululo.
I-HEC iyi-polymer engeyona i-ionic engazweli ku-pH futhi inokusebenza okuhle nokuzinza phezu kwebanga le-pH elibanzi. Lokhu kuyenza isebenze kabanzi ezinhlelweni eziningi, ikakhulukazi lapho kudingeka khona ukusebenza okuzinzile kwama-thickeners nabadali befilimu. Noma kunjalo, kusabalulekile ukucabangela ukuthi ukuzinza nokusebenza kwe-HEC kungase kuthinteke kanjani ngaphansi kwezimo ze-pH ezimbi kakhulu noma uma kusetshenziswa nezinye izithako ezizwela i-pH. Ezindabeni zokuzwela kwe-pH ezinhlelweni ezithile, kutuswa ukuba kwenziwe ukuhlola nokuqinisekisa okuhambisanayo ngaphambi kokusetshenziswa kwangempela ukuze kuqinisekiswe ukuthi i-HEC ingenza kahle ngaphansi kwezimo ezilindelekile.
Isikhathi sokuthumela: Aug-19-2024