I-Cellulose ether yipolymer yokwenziwa eyenziwe ngeselulosi yendalo njengemathiriyeli ekrwada ngokuguqulwa kweekhemikhali. I-ether ye-cellulose iphuma kwi-cellulose yendalo, imveliso ye-cellulose ether kunye ne-polymer yokwenziwa yahlukile, eyona nto isisiseko se-cellulose, i-polymer compounds yendalo. Ngenxa yobungcali besakhiwo se-cellulose yendalo, i-cellulose ngokwayo ayinakho ukusabela nge-etherifying agent. Kodwa emva kokunyangwa kwe-ejenti yokudumba, iibhondi ze-hydrogen ezomeleleyo phakathi kwamatyathanga emolekyuli kunye namatyathanga atshatyalaliswa, kwaye umsebenzi weqela le-hydroxyl wakhutshelwa kwi-alkali cellulose kunye nekhono lokuphendula, kunye ne-cellulose ether yafunyanwa ngokusabela kwe-etherifying agent-OH iqela kwi - OKANYE iqela.
Iimpawu ze-cellulose ethers zixhomekeke kuhlobo, inani kunye nokuhanjiswa kwezinto ezithatha indawo. Ukuhlelwa kwe-ether ye-cellulose nayo isekelwe kuhlobo lwabaxumi, i-degree of etherification, i-solubility kunye nesicelo esihambelanayo sinokuhlelwa. Ngokohlobo lwababambeleyo kwitsheyini yemolekyuli, inokwahlulwa ibe yi-ether enye kunye ne-ether edibeneyo. I-MC iqhele ukusetyenziswa njenge-ether enye, ngelixa i-HPmc iyi-ether exutywe. I-Methyl cellulose ether MC yiyunithi yeglucose yeseli yendalo kwi-hydroxyl yi-methoxide endaweni yefomyula yesakhiwo semveliso [CO H7O2 (OH) 3-H (OCH3) H] X, i-hydroxypropyl methyl cellulose ether HPmc yinxalenye ye-hydroxyl yinxalenye yemethoxide endaweni, enye inxalenye yehydroxypropyl endaweni yemveliso, Ifomula yolwakhiwo [C6H7O2 (OH) 3-MN (OCH3) M [OCH2CH (OH) CH3] N] I-X kunye ne-hydroxyethyl methyl cellulose ether HEmc, esetyenziswa kakhulu kwaye ithengiswa kwimarike.
Ukusuka kwi-solubility inokwahlulwa ibe yintlobo ye-ionic kunye nohlobo lwe-non-ionic. Amanzi-anyibilikayo non-ionic cellulose ether ikakhulu yenziwe alkyl ether kunye hydroxyl alkyl ether ezimbini iintlobo ezahlukeneyo. I-Ionic Cmc isetyenziswa ikakhulu kwi-synthetic detergent, textile, printing, food and petroleum exploitation. I-non-ionic MC, i-HPmc, i-HEmc kunye nezinye ezisetyenziswa kakhulu kwizinto zokwakha, iingubo ze-latex, amayeza, i-chemistry yemihla ngemihla kunye neminye imiba. Njenge-ejenti yokuqina, i-arhente yokugcina amanzi, i-stabilizer, i-dispersant, i-agent eyenza ifilimu.
Ukugcinwa kwamanzi kwi-ether cellulose
Kwimveliso yezinto zokwakha, ngakumbi udaka oluxubeneyo olomileyo, i-cellulose ether idlala indima engenakuphinda ithathelwe indawo, ngakumbi kwimveliso yodaka olukhethekileyo (udaka olulungisiweyo), luyinxalenye eyimfuneko.
Indima ebalulekileyo ye-ether ye-cellulose e-soluble water-soluble kwi-mortar ikakhulu inemiba emithathu, enye inamandla okugcina amanzi, okwesibini yimpembelelo yodaka kunye ne-thixotropy, kwaye okwesithathu kukusebenzisana nesamente.
Ukugcinwa kwamanzi kwi-ether cellulose, kuxhomekeke kwisiseko se-hydroscopicity, ukubunjwa kodaka, ubuninzi be-mortar layer, imfuno yamanzi yodaka, ixesha lokujiya kwe-condensation. Ukugcinwa kwamanzi kwe-cellulose ether kuvela ekunyibilikeni kunye nokuphelelwa ngamanzi emzimbeni we-cellulose ether ngokwayo. Kuyaziwa ukuba i-cellulose molecular chain chain, nangona iqulethe inani elikhulu lamaqela e-OH ane-hydrated kakhulu, ayinyibiliki emanzini ngenxa yesakhiwo sayo se-crystalline. Isakhono sokugalela amanzi samaqela e-hydroxyl sisodwa akwanelanga ukuhlawulela i-intermolecular bond ye-hydrogen eyomeleleyo kunye nemikhosi ye-van der Waals. Xa i-substituents zingeniswa kwitsheyina le-molecular, kungekhona nje abathintekayo abatshabalalisa ikhonkco le-hydrogen, kodwa kunye neebhondi ze-hydrogen ze-interchain ziyaphulwa ngenxa yokudityaniswa kwezinto ezihambelanayo phakathi kwamatyathanga akufutshane. Izikhulu ezithatha indawo, kokukhona umgama omkhulu phakathi kweeathom. Ukutshatyalaliswa okukhulu kwesiphumo se-hydrogen bond, ukwanda kwe-cellulose lattice, isisombululo kwi-ether cellulose iba yi-soluble water-soluble, ukusekwa kwesisombululo esiphezulu se-viscosity. Njengoko iqondo lokushisa liphakama, i-hydration ye-polymer iyancipha kwaye amanzi phakathi kwamaketanga akhutshelwa ngaphandle. Xa i-dehydrating effect yanele, iamolekyu ziqala ukudibanisa kwaye i-gel igoqa kwi-network-dimensional network. Izinto ezichaphazela ukugcinwa kwamanzi kwi-mortar ziquka i-cellulose ether viscosity, i-dosage, i-particle fineness kunye nobushushu benkonzo.
Inkulu i-viscosity ye-cellulose ether, ngcono ukugcinwa kwamanzi, i-viscosity yesisombululo se-polymer. Ubunzima be-molecular (i-degree of polymerization) ye-polymer iphinda inqunywe ngubude kunye ne-morphology yesakhiwo se-molecular of the chain, kwaye ukuhanjiswa kwenani lee-substituents kuchaphazela ngokuthe ngqo uluhlu lwe-viscosity. [eta] = Km alpha
I-viscosity yangaphakathi yezisombululo zepolymer
Ubunzima bemolekyuli ye-polymer
α ipholima yophawu olungaguqukiyo
K i-viscosity isisombululo se-coefficient
I-viscosity yesisombululo sepolymer ixhomekeke kubunzima be-molecular of polymer. I-viscosity kunye noxinzelelo lwezisombululo ze-cellulose ether zihambelana nezicelo ezahlukeneyo. Ke ngoko, i-ether yeselulosi nganye ineenkcazo ezininzi ezahlukeneyo ze-viscosity, ukulawulwa kwe-viscosity kwakhona ikakhulu ngokuthotywa kwe-alkali cellulose, oko kukuthi ukwaphuka kwekhonkco le-cellulose yemolekyuli ukufikelela.
Ubungakanani besuntswana, incinci incinci, ngcono ukugcinwa kwamanzi. Amasuntswana amakhulu e-cellulose ether yokunxibelelana namanzi, umphezulu ngokukhawuleza unyibilike kwaye wenze ijeli ukusonga izinto zokuthintela iimolekyuli zamanzi ukuba zingaqhubeki nokungena, ngamanye amaxesha ixesha elide lixhokonxa alinakuhlakazwa ngokulinganayo, ukubunjwa kwesisombululo esinodaka okanye iagglomerate. Ukunyibilika kwe-ether ye-cellulose yenye yezinto zokukhetha i-ether ye-cellulose.
Ukutyeba kunye ne-thixotropy ye-cellulose ether
Isiphumo sesibini se-cellulose ether - ukutyeba kuxhomekeke kwi: i-cellulose ether polymerization degree, i-concentration concentration, i-shear rate, iqondo lokushisa kunye nezinye iimeko. Ipropati ye-gelation yesisombululo iyingqayizivele kwi-alkyl cellulose kunye ne-derivatives yayo eguqulwayo. Iimpawu zeGelation zihambelana neqondo lokutshintshwa, ukugxilwa kwesisombululo kunye nezongezo. Kwizinto ze-hydroxyl alkyl modified derivatives, iipropati zejeli nazo zihambelana neqondo lokuguqulwa kwe-hydroxyl alkyl. Kuba isisombululo soxinaniso lwe-viscosity ephantsi ye-MC kunye ne-HPmc inokulungiswa 10% -15% isisombululo soxinaniso, i-viscosity ephakathi kwe-MC kunye ne-HPmc inokulungiswa 5% -10% isisombululo kunye ne-viscosity ephezulu ye-MC kunye ne-HPmc inokulungiswa kuphela 2% -3% isisombululo, kwaye ngokuqhelekileyo i-viscosity ye-cellulose ether iphinda ihlelwe nge-1% -2% isisombululo. Ubunzima obuphezulu be-cellulose ye-ether thickener ukusebenza kakuhle, ukuxinwa okufanayo kwesisombululo, iipolymers ze-molecular weight ezahlukeneyo zine-viscosity eyahlukileyo, i-viscosity kunye ne-molecular weight ingabonakaliswa ngolu hlobo lulandelayo, [η] = 2.92 × 10-2 (DPn) 0.905, i-DPn yi-avareji iqondo eliphezulu lepolymerization. I-ether ye-molecular weight low cellulose ukongeza ngakumbi ukuphumeza i-viscosity ekujoliswe kuyo. I-viscosity yayo ixhomekeke kancinci kwireyithi yokucheba, i-viscosity ephezulu ukufezekisa i-viscosity ekujoliswe kuyo, isixa esifunekayo ukongeza ngaphantsi, i-viscosity ixhomekeke ekusebenzeni kokuqina. Ngoko ke, ukufezekisa ukuhambelana okuthile, umlinganiselo othile we-cellulose ether (ukugxilwa kwesisombululo) kunye ne-viscosity yesisombululo kufuneka iqinisekiswe. Ukushisa kwe-gelation yesisombululo kuncipha ngokuhambelana nokunyuka koxinzelelo lwesisombululo, kwaye i-gelation yenzeke kwindawo yokushisa emva kokufikelela kugxininiso oluthile. I-HPmc inoxinzelelo oluphezulu lwe-gelation kwiqondo lobushushu begumbi.
Ukuhambelana kungalungiswa kwakhona ngokukhetha ubungakanani be-particle kunye ne-cellulose ethers kunye nemigangatho eyahlukeneyo yokuguqulwa. Oku kuthiwa ukuguqulwa kukuqaliswa kweqela le-hydroxyl alkyl kwinqanaba elithile lokutshintshwa 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-hydroxyl. Iipropati ezahlukeneyo ze-cellulose ether ziyafuneka ngokuguqula amaxabiso ahambelanayo ahambelanayo weentlobo ezimbini zezinto ezibambeleyo.
ubudlelwane phakathi kokungaguquguquki kunye nokuguqulwa. Kwi-Figure 5, ukongezwa kwe-cellulose ether kuchaphazela ukusetyenziswa kwamanzi omdaka kunye nokutshintsha umlinganiselo we-water-binder yamanzi kunye ne-samente, okuyimpembelelo yokuqina. Ukuphakama kwedosi, kokukhona ukusetyenziswa kwamanzi.
I-cellulose ethers esetyenziswe kwizinto zokwakha ze powdery kufuneka ichithe ngokukhawuleza emanzini abandayo kwaye inike inkqubo ngokuhambelana okufanelekileyo. Ukuba umlinganiselo wokucheba onikiweyo usagungxuleka kwaye i-colloidal yimveliso ekumgangatho ophantsi okanye ekumgangatho ophantsi.
Kukwakho unxulumano oluhle lomgca phakathi kokungaguquguquki kodaka lwesamente kunye nethamo leselulosi etha, i-ether eselulosi inokunyusa kakhulu i-viscosity yodaka, okukhona idosi iphezulu, kokukhona isiphumo sicace ngakumbi.
I-cellulose ether isisombululo samanzi kunye ne-viscosity ephezulu ine-thixotropy ephezulu, enye yeempawu ze-cellulose ether. Izisombululo ezinamanzi zohlobo lwe-Mc iipolima zihlala zine-pseudoplastic, non-thixotropic fluidity ngaphantsi kobushushu bejeli yazo, kodwa iipropathi zokugeleza kwe-Newtonian kumazinga aphantsi okucheba. I-Pseudoplasticity iyanda ngokunyuka kobunzima bemolekyuli okanye ukuxinwa kwe-cellulose ether kwaye izimeleyo kuhlobo olubambekayo kunye nesidanga. Ngoko ke, i-cellulose ethers yebakala elifanayo le-viscosity, nokuba i-MC, i-HPmc okanye i-HEmc, ihlala ibonisa iimpawu ezifanayo ze-rheological nje ukuba ugxininiso kunye nobushushu buhlala buhleli. Xa izinga lokushisa linyuka, i-gel yesakhiwo yenziwa kwaye ukuhamba okuphezulu kwe-thixotropic kwenzeka. I-cellulose ethers ene-concentration ephezulu kunye ne-viscosity ephantsi ibonisa i-thixotropy nangaphantsi kobushushu be-gel. Lo mhlaba unenzuzo enkulu kulwakhiwo lodaka lwesakhiwo ukulungisa ukuhamba nokuhamba kwepropati ejingayo. 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, ukunciphisa okuhambelanayo kokunyibilika kwayo, okunempembelelo embi Ugxininiso lodaka kunye nokusebenza kolwakhiwo. Okukhona i-viscosity iphezulu, kokukhona kucaca ngakumbi ukutyeba kodaka, kodwa ayilulo ubudlelwane obupheleleyo. Enye i-viscosity ephantsi, kodwa i-ether cellulose eguqulwayo ekuphuculeni amandla esakhiwo sodaka olumanzi lunomsebenzi ogqwesileyo ngakumbi, ngokunyuka kwe-viscosity, ukugcinwa kwamanzi kwe-cellulose ether kuphuculwe.
Ixesha lokuposa: Mar-30-2022