Focus on Cellulose ethers

Indlela yokulawula ukuqina kunye ne-thixotropy ye-cellulose ether?

Isiphumo sokutyeba se-cellulose ether sixhomekeke kwi: iqondo lepolymerization ye-cellulose ether, i-concentration yesisombululo, izinga le-shear, ubushushu kunye nezinye iimeko. Ipropati ye-gelling yesisombululo iyingqayizivele kwi-alkyl cellulose kunye ne-derivatives yayo eguqulwayo. Iimpawu ze-gelation zihambelana neqondo lokutshintshwa, ukugxininiswa kwesisombululo kunye nezongezo. Kwizinto ze-hydroxyalkyl eziguqulweyo, iipropathi zejeli zikwanxulumene nenqanaba lokuguqulwa kwe-hydroxyalkyl. Kwi-viscosity ephantsi ye-MC kunye ne-HPMC, isisombululo se-10% -15% sinokulungiswa, i-viscosity ephakathi MC kunye ne-HPMC ingalungiswa isisombululo se-5% -10%, kunye ne-viscosity ephezulu ye-MC kunye ne-HPMC inokulungiselela kuphela isisombululo se-2% -3%, kwaye ngokuqhelekileyo i-viscosity classification ye-cellulose ether iphinda ihlelwe kunye ne-1% -2% isisombululo.
I-high-molecular-weight cellulose ether ine-high thickening efficient, kwaye iipolymers ezinobunzima be-molecular ezahlukeneyo zine-viscosity ezahlukeneyo kwisisombululo esifanayo soxinaniso. I-viscosity ekujoliswe kuyo inokufezekiswa kuphela ngokongeza inani elikhulu le-ether ye-cellulose ephantsi ye-molecular weight. I-viscosity yayo inokuxhomekeka okuncinci kwireyithi yokucheba, i-viscosity ephezulu ifikelela kwi-viscosity ekujoliswe kuyo, kwaye inani elifunekayo lokongeza lincinci, kwaye i-viscosity ixhomekeke ekusebenzeni kakuhle. Ngoko ke, ukufezekisa ukuhambelana okuthile, inani elithile le-cellulose ether (ukugxilwa kwesisombululo) kunye ne-viscosity yesisombululo kufuneka kuqinisekiswe. Iqondo lokushisa le-gel yesisombululo liyancipha ngokuhambelana nokunyuka koxinzelelo lwesisombululo, kunye neegels kwiqondo lokushisa emva kokufikelela kwinqanaba elithile. Uxinzelelo lwe-gelling lwe-HPMC luphezulu ngokwentelekiso kwiqondo lobushushu begumbi.
Ukuhambelana kungalungiswa ngokukhetha ubungakanani besuntswana kunye nokukhetha i-cellulose ethers ngeedigri ezahlukeneyo zokuguqulwa. Into ebizwa ngokuba yinguquko kukwazisa iqondo elithile lokutshintshwa kwamaqela e-hydroxyalkyl kwisakhiwo samathambo e-MC. Ngokuguqula amaxabiso ahambelanayo atshintshileyo atshintshiweyo amabini, oko kukuthi, i-DS kunye ne-MS imilinganiselo ehambelanayo yokutshintshwa kwamaqela e-methoxy kunye ne-hydroxyalkyl esihlala siyithetha. Iimfuno ezahlukeneyo zokusebenza ze-cellulose ether zinokufunyanwa ngokutshintsha amaxabiso ahambelanayo ahambelanayo amabini abambeleyo.
I-high-viscosity cellulose ether isisombululo samanzi sine-thixotropy ephezulu, ekwayimpawu enkulu ye-cellulose ether. Izisombululo ezimanzi ze-MC polymers zihlala zine-pseudoplastic kunye ne-non-thixotropic fluidity ngaphantsi kobushushu bejeli yazo, kodwa iipropathi ezihamba ngeNewtonian kumazinga aphantsi okucheba. I-Pseudoplasticity iyanda kunye nobunzima be-molecular okanye i-concentration ye-cellulose ether, kungakhathaliseki ukuba luhlobo luni lwe-substitute kunye neqondo lokutshintshwa. Ngoko ke, i-cellulose ethers yebakala elifanayo le-viscosity, kungakhathaliseki ukuba i-MC, i-HPMC, i-HEMC, iya kuhlala ibonisa iimpawu ezifanayo ze-rheological nje ngokuba ugxininiso kunye nobushushu bugcinwa rhoqo. Iigels zesakhiwo zenziwe xa ubushushu buphakanyisiwe, kwaye ukuhamba okuphezulu kwe-thixotropic kwenzeka. Uxinzelelo oluphezulu kunye ne-viscosity ephantsi ye-cellulose ethers ibonisa i-thixotropy nangaphantsi kweqondo lokushisa le-gel. Lo mhlaba unenzuzo enkulu kuhlengahlengiso lomgangatho kunye nokuncipha kulwakhiwo lodaka lwesakhiwo.
Kufuneka kucaciswe apha ukuba i-viscosity ephezulu ye-ether cellulose, ngcono ukugcinwa kwamanzi, kodwa ukuphakama kwe-viscosity, ukuphakama kwe-molecular weight ye-cellulose ether, kunye nokuncipha okuhambelanayo kwi-solubility yayo, enempembelelo embi. kugxininiso lodaka kunye nokusebenza kolwakhiwo. Ukuphakama kwe-viscosity, kuyabonakala ngakumbi umphumo wokuqina kumdaka, kodwa awulingani ngokupheleleyo. Enye i-viscosity ephakathi kunye nephantsi, kodwa i-ether ye-cellulose eguqulwayo inomsebenzi ongcono ekuphuculeni amandla okwakhiwa kodaka olumanzi. Ngokunyuka kwe-viscosity, ukugcinwa kwamanzi kwe-cellulose ether kuphucula.


Ixesha lokuposa: Mar-20-2023
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