I-Cellulose ether yipolymer yokwenziwa eyenziwe kwi-cellulose yendalo ngokuguqulwa kweekhemikhali. I-ether ye-cellulose iphuma kwi-cellulose yendalo. Ukuveliswa kwe-cellulose ether kuyahluka kwiipolymers zokwenziwa. Izinto zayo ezisisiseko ziyi-cellulose, i-polymer compound yendalo. Ngenxa yobungcali besakhiwo se-cellulose yendalo, i-cellulose ngokwayo ayinakho ukusabela kunye nee-etherification agents. Nangona kunjalo, emva kokunyangwa kwe-ejenti yokuvuvukala, iibhondi ze-hydrogen ezomeleleyo phakathi kwamatyathanga e-molecular kunye namatyathanga atshatyalaliswa, kwaye ukukhutshwa okusebenzayo kweqela le-hydroxyl kuba yi-alkali cellulose esebenzayo. Fumana i-cellulose ether.
Iimpawu ze-cellulose ethers zixhomekeke kuhlobo, inani kunye nokuhanjiswa kwezinto ezithatha indawo. Ulwahlulo lwe-cellulose ethers lukwasekelwe kuhlobo lwabaxumi, i-degree of etherification, i-solubility kunye neepropati ezinxulumene nesicelo. Ngokohlobo lwababambeleyo kwitsheyini yemolekyuli, inokwahlulwa ibe yi-monoether kunye ne-ether edibeneyo. I-MC esiqhele ukuyisebenzisa yi-monoether, kwaye i-HPMC ixutywe i-ether. I-Methyl cellulose ether MC yimveliso emva kweqela le-hydroxyl kwiyunithi ye-glucose ye-cellulose yendalo ifakwe endaweni ye-methoxy. Yimveliso efunyenwe ngokutshintsha inxalenye yeqela le-hydroxyl kwiyunithi kunye neqela le-methoxy kunye nenye inxalenye kunye neqela le-hydroxypropyl. Ifomula yolwakhiwo ithi [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)CH3]n]x Hydroxyethyl methyl cellulose ether HEMC, ezi zezona ntlobo zisetyenziswa kakhulu kwaye zithengiswa kwimarike.
Ngokubhekiselele kwi-solubility, inokwahlulwa ibe yi-ionic kunye ne-non-ionic. Ii-ether ze-cellulose ezingenayo i-ionic ezinyibilikayo zamanzi zenziwa ikakhulu ngamacandelo amabini e-alkyl ethers kunye ne-hydroxyalkyl ethers. I-Ionic CMC isetyenziswa ikakhulu kwizicoci zokwenziwa, ushicilelo lwelaphu kunye nokudaya, ukutya kunye nokuhlola ioli. I-non-ionic MC, i-HPMC, i-HEMC, njl njl. zisetyenziswa kakhulu kwizinto zokwakha, iingubo ze-latex, amayeza, iikhemikhali zemihla ngemihla, njl njl. Isetyenziswe njenge-thickener, i-agent egcina amanzi, i-stabilizer, i-dispersant kunye ne-agent eyenza ifilimu.
Ukugcinwa kwamanzi kwe-cellulose ether
Ekuvelisweni kwezinto zokwakha, ngakumbi udaka oluxubeneyo olomileyo, i-cellulose ether idlala indima engenakuphinda ithathelwe indawo, ngakumbi kwimveliso yodaka olukhethekileyo (udaka olulungisiweyo), luyinto eyimfuneko kwaye ibalulekileyo.
Indima ebalulekileyo ye-ether ye-cellulose e-soluble yamanzi kwi-mortar ikakhulu inemiba emithathu, enye inamandla okugcina amanzi, enye yimpembelelo ehambelanayo kunye ne-thixotropy yodaka, kwaye okwesithathu kukusebenzisana nesamente.
Ukugcinwa kwamanzi kwi-ether ye-cellulose kuxhomekeke ekufunjweni kwamanzi kwinqanaba lesiseko, ukubunjwa kodaka, ubukhulu bodaka lodaka, imfuno yamanzi yodaka, kunye nexesha lokumisela izinto zokumisela. Ukugcinwa kwamanzi kwe-cellulose ether ngokwayo kuvela kwi-solubility kunye nokuphelelwa ngamanzi kwe-cellulose ether ngokwayo. Njengoko sonke sisazi, nangona i-cellulose i-molecular chain iqulethe inani elikhulu lamaqela e-OH anamandla, ayinyibiliki emanzini, kuba isakhiwo se-cellulose sinezinga eliphezulu le-crystallinity. Isakhono se-hydration samaqela e-hydroxyl iyodwa akwanelanga ukugubungela iibhondi ze-hydrogen ezomeleleyo kunye ne-van der Waals phakathi kwee-molecule. Ngoko ke, idumba kuphela kodwa ayinyibiliki emanzini. Xa i-substituent ingeniswa kwitsheyina le-molecular, kungekhona nje i-substituent etshabalalisa ikhonkco le-hydrogen, kodwa kunye ne-interchain ye-hydrogen bond iyatshatyalaliswa ngenxa yokutshatyalaliswa kwe-substituent phakathi kwamatyathanga akufutshane. Ubukhulu be-substitute, umgama omkhulu phakathi kweemolekyuli. Umgama mkhulu. Umphumo omkhulu wokutshabalalisa iibhondi ze-hydrogen, i-ether ye-cellulose iba yi-soluble yamanzi emva kokuba i-cellulose lattice yanda kwaye isisombululo singena, senza isisombululo esiphezulu se-viscosity. Xa izinga lokushisa liphakama, i-hydration ye-polymer iyancipha, kwaye amanzi phakathi kwamaketanga akhutshwa ngaphandle. Xa isiphumo sokuchithwa kwamanzi sanele, iamolekyu ziqala ukudibanisa, zenza i-gel yesakhiwo senethiwekhi ye-dimensional emithathu kwaye ihlanganiswe ngaphandle. Izinto ezichaphazela ukugcinwa kwamanzi kwi-mortar ziquka i-viscosity ye-cellulose ether, inani elongezelelweyo, ukucocwa kweengqungquthela kunye nokushisa kokusetyenziswa.
Ukuphakama kwe-viscosity ye-cellulose ether, ngcono ukusebenza kokugcinwa kwamanzi, kunye nokuphakama kwe-viscosity yesisombululo se-polymer. Ngokuxhomekeke kubunzima bemolekyuli (i-polymerization degree) yepolymer, iphinda igqitywe ngobude be-chain yesakhiwo se-molecular kunye nokumila kwekhonkco, kunye nokuhanjiswa kweentlobo kunye nobuninzi bezinto ezithintekayo nazo zichaphazela ngokuthe ngqo uluhlu lwe-viscosity. [η]=Kmα
[η] I-viscosity yangaphakathi yesisombululo sepolymer
m polymer ubunzima bemolekyuli
α ipholima yophawu olungaguqukiyo
K i-viscosity isisombululo se-coefficient
I-viscosity yesisombululo sepolymer ixhomekeke kubunzima be-molecular of polymer. I-viscosity kunye nokuxinwa kwesisombululo se-cellulose ether ihambelana nesicelo kwiinkalo ezahlukeneyo. Ke ngoko, i-ether yeselulosi nganye ineenkcazo ezininzi ezahlukeneyo ze-viscosity, kwaye uhlengahlengiso lwe-viscosity lubonakaliswa ikakhulu ngokuthotywa kwe-alkali cellulose, oko kukuthi, ukuqhawuka kwamakhonkco e-cellulose.
Ubuninzi be-ether ye-cellulose eyongeziweyo kwidaka, ngcono ukugcinwa kwamanzi, kunye nokuphakama kwe-viscosity, ngcono ukugcinwa kwamanzi.
Ubungakanani be-particle, i-fineral particle, ngcono ukugcinwa kwamanzi. Jonga umzobo 3. Emva kokuba i-particle enkulu ye-cellulose ether idibanisa namanzi, i-surface iyancibilika ngokukhawuleza kwaye yenza i-gel ukugubungela izinto zokukhusela iimolekyuli zamanzi ukuba ziqhubeke nokungena. Ngaphantsi kokusasazwa okufanayo kuyanyibilika, yenze isisombululo esinamafu okanye i-agglomerates. Ichaphazela kakhulu ukugcinwa kwamanzi kwe-cellulose ether, kwaye ukunyibilika yenye yezinto zokukhetha i-cellulose ether.
Ukutyeba kunye Thixotropy yeCellulose Etere
Umsebenzi wesibini we-cellulose ether - ukuqina, kuxhomekeke kwi: iqondo le-polymerization ye-cellulose ether, i-concentration concentration, i-shear rate, iqondo lokushisa 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. Kwiimveliso eziguqulweyo ze-hydroxyalkyl, iipropati zejeli nazo zihambelana neqondo 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 Ukuhlelwa kwe-viscosity ye-cellulose ether iphinda ihlelwe kunye ne-1% -2% isisombululo. Ubunzima bemolekyuli ephezulu ye-cellulose ether inokuqina okuphezulu. Kwisisombululo esifanayo soxinaniso, iipolymers ezinobunzima beemolekyuli ezahlukeneyo zinee-viscosities ezahlukeneyo. Iqondo eliphezulu. I-viscosity ekujoliswe kuyo inokufezekiswa kuphela ngokongeza inani elikhulu le-ether ye-cellulose ephantsi ye-molecular weight. I-viscosity yayo inokuxhomekeka okuncinci kwireyithi yokucheba, kwaye 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-cellulose ethers esetyenziswe kwizinto zokwakha ezinomgubo kufuneka ichithe ngokukhawuleza emanzini abandayo kwaye inike ukuhambelana okufanelekileyo kwesistim. Ukuba kunikwe umlinganiselo othile wokucheba, isuka ibe yibloko ejikelezayo kunye ne-colloidal, eyimveliso ekumgangatho ophantsi okanye ekumgangatho ophantsi.
Kukwakho nobudlelwane obuhle bomgca phakathi kokungaguquguquki kwentlama yesamente kunye nedosi ye-cellulose ether. I-ether ye-cellulose inokunyusa kakhulu i-viscosity yodaka. Ubukhulu bedosi, kokukhona isiphumo esicacileyo.
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 ye-cellulose, ngcono ukugcinwa kwamanzi, kodwa ukuphakama kwe-viscosity, ukuphakama kwe-molecular weight ye-cellulose ether, kunye nokuncipha okuhambelanayo kwi-solubility yayo, enefuthe elibi. kugxininiso lodaka kunye nokusebenza kolwakhiwo. Ukuphakama kwe-viscosity, kuyabonakala ngakumbi umphumo wokuqina kumdaka, kodwa awulingani ngokupheleleyo. I-viscosity ethile 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: Nov-22-2022