I-Cellulose ether yi-polymer eyenziwe nge-cellulose yendalo njengezinto eziluhlaza ngokuguqulwa kweekhemikhali. I-Cellulose ether ivela kwi-cellulose yendalo, ukuveliswa kwe-cellulose ether kunye ne-polymer eyenziweyo yahlukile, eyona nto iphambili yi-cellulose, iikhompawundi ze-polymer yendalo. Ngenxa yobuchule besakhiwo se-cellulose yendalo, i-cellulose ngokwayo ayinakho ukusabela kunye ne-etherifying agent. Kodwa emva konyango lwe-ejenti yokudumba, iibhondi ze-hydrogen ezinamandla phakathi kwee-molecular chains kunye nee-chains zatshatyalaliswa, kwaye umsebenzi weqela le-hydroxyl wakhululwa kwi-alkali cellulose enekhono lokuphendula, kwaye i-cellulose ether yafunyanwa nge-reaction ye-etherifying agent — iqela le-OH kwiqela le-OR.
Iimpawu zee-ether ze-cellulose zixhomekeke kuhlobo, inani kunye nokusasazwa kwezinto ezithatha indawo. Uhlu lwe-ether ye-cellulose lukwasekelwe kuhlobo lwezinto ezithatha indawo, inqanaba le-etherification, ukunyibilika kunye nokusetyenziswa okunxulumene noko kunokuhlelwa. Ngokweentlobo zezinto ezithatha indawo kwi-molecular chain, inokwahlulwa ibe yi-ether enye kunye ne-ether exutyiweyo. I-MC idla ngokusetyenziswa njenge-ether enye, ngelixa i-HPmc iyi-ether exutyiweyo. I-Methyl cellulose ether MC yiyunithi yendalo ye-cellulose glucose kwi-hydroxyl yi-methoxide ethathelwe indawo yifomyula yesakhiwo semveliso [CO H7O2 (OH) 3-H (OCH3) H] X, i-hydroxypropyl methyl cellulose ether HPmc yiyunithi kwi-hydroxyl yinxalenye ye-methoxide ethathelwe indawo, enye inxalenye yemveliso ethathelwe indawo yi-hydroxypropyl, Ifomyula yesakhiwo yi [C6H7O2 (OH) 3-MN (OCH3) M [OCH2CH (OH) CH3] N] X kunye ne-hydroxyethyl methyl cellulose ether HEmc, esetyenziswa kakhulu kwaye ithengiswa kwimarike.
Ukusuka ekunyibilikeni, kunokwahlulwahlulwa lube loluhlobo lwe-ionic nohlobo olungelulo lwe-ionic. I-ether ye-cellulose engaseluliyo emanzini yenziwe ikakhulu yi-alkyl ether kunye ne-hydroxyl alkyl ether, uluhlu lweentlobo ezimbini. I-Cmc ye-Ionic isetyenziswa kakhulu kwisepha yokwenziwa, kwilaphu, ekuprinteni, ekutyeni nasekusetyenzisweni kwepetroleum. I-MC engelulo lwe-ionic, i-HPmc, i-HEmc kunye nezinye ezisetyenziswa kakhulu kwizixhobo zokwakha, kwiingubo ze-latex, kumayeza, kwikhemistri yemihla ngemihla nakwezinye izinto. Njenge-arhente yokutyeba, i-arhente yokugcina amanzi, i-stabilizer, i-dispersant, i-arhente yokwenza ifilimu.
Ukugcinwa kwamanzi kwi-cellulose ether
Kwimveliso yezinto zokwakha, ingakumbi udaka oluxutyiweyo olomileyo, i-cellulose ether idlala indima engenakutshintshwa, ingakumbi kwimveliso yodaka olukhethekileyo (udaka oluguquliweyo), yinxalenye ebalulekileyo.
Indima ebalulekileyo ye-ether ye-cellulose enyibilikayo emanzini kwi-mortar ikakhulu inemiba emithathu, enye kukwazi ukugcina amanzi kakuhle, eyesibini yimpembelelo yokuhambelana kwe-mortar kunye ne-thixotropy, kwaye eyesithathu kukusebenzisana nesamente.
Ukugcinwa kwamanzi e-cellulose ether, kuxhomekeke kwisiseko se-hydroscopicity, ukwakheka kwe-mortar, ubukhulu be-mortar layer, imfuno yamanzi e-mortar, ixesha lokufuma kwezinto ezifumileyo. Ukugcinwa kwamanzi e-cellulose ether kuvela ekunyibilikeni nasekuphelelweni yi-cellulose ether ngokwayo. Kuyaziwa ukuba ii-cellulose molecular chains, nangona ziqulathe inani elikhulu lamaqela e-OH anamanzi amaninzi, azinyibiliki emanzini ngenxa yesakhiwo sazo esiqinileyo. Amandla okufuthumala kwamanzi amaqela e-hydroxyl kuphela awanelanga ukuhlawulela ii-hydrogen bonds ezinamandla ze-intermolecular kunye ne-van der Waals force. Xa ii-substituents zingeniswa kwi-molecular chain, ayizizo kuphela ii-substituents ezitshabalalisa i-hydrogen chain, kodwa nee-interchain hydrogen bonds ziyaqhekeka ngenxa yokudibana kwee-substituents phakathi kwee-chain ezikufutshane. Okukhona ii-substituents zinkulu, kokukhona umgama phakathi kwee-molecules umkhulu. Okukhona ukutshatyalaliswa kwe-hydrogen bond effect kukhulu, ukwanda kwe-cellulose lattice, isisombululo kwi-cellulose ether siba ngamanzi anyibilikayo, ukwakheka kwesisombululo se-viscosity ephezulu. Njengoko ubushushu bunyuka, ukufuma kwepolymer kuyancipha kwaye amanzi phakathi kweetyathanga ayaphuma. Xa isiphumo sokufuma sanele, iimolekyuli ziqala ukuhlangana kwaye ijeli igoqeka kwinethiwekhi enamacala amathathu. Izinto ezichaphazela ukugcinwa kwamanzi kwi-mortar ziquka i-cellulose ether viscosity, idosi, ubuncinci be-particle kunye nobushushu benkonzo.
Okukhona i-viscosity ye-cellulose ether inkulu, kokukhona ukusebenza kokugcinwa kwamanzi kuphucuka, i-viscosity yesisombululo se-polymer. Ubunzima be-molecular (i-degree of polymerization) ye-polymer bukwamiselwa bubude kunye ne-morphology yesakhiwo se-molecular se-chain, kwaye ukusasazwa kwenani lezinto ezithatha indawo kuchaphazela ngokuthe ngqo uluhlu lwe-viscosity. [eta] = Km alpha
Ubunzulu obungaphakathi bezisombululo zepolymer
Ubunzima be-molecular ye-polymer ye-M
uphawu lwe-α polymer olungaguqukiyo
Isisombululo se-K viscosity coefficient
Ubunzima besisombululo sepolymer buxhomekeke kubunzima bemolekyuli yepolymer. Ubunzima kunye noxinzelelo lwezisombululo ze-cellulose ether zinxulumene nezicelo ezahlukeneyo. Ke ngoko, i-cellulose ether nganye ineenkcazo ezahlukeneyo ze-viscosity, ukulawulwa kwe-viscosity kukwakho ngokugqithisileyo ngokuwohloka kwe-alkali cellulose, oko kukuthi ukwaphuka kwe-cellulose molecular chain ukuze kufezekiswe.
Ngobungakanani besuntswana, okukhona isuntswana licolekile, kokukhona ukugcinwa kwamanzi kubhetele. Amasuntswana amakhulu e-cellulose ether adibana namanzi, umphezulu uyanyibilika ngoko nangoko uze wenze ijeli yokusonga izinto ukuze kuthintelwe ukuba iimolekyuli zamanzi zingaqhubeki zingena, ngamanye amaxesha ukuxutywa ixesha elide akunakusasazeka ngokulinganayo, ukwenziwa kwesisombululo esinodaka okanye i-agglomerate. Ukunyibilika kwe-cellulose ether yenye yezinto ezibangela ukuba ukhethe i-cellulose ether.
Ukuqina kunye ne-thixotropy ye-cellulose ether
Isiphumo sesibini se-cellulose ether – ukuqina kuxhomekeke kwi: i-cellulose ether polymerization degree, i-solution concentration, i-shear rate, i-temperature kunye nezinye iimeko. I-gelation property yesisombululo ikhethekile kwi-alkyl cellulose kunye ne-modified derivatives zayo. Iimpawu ze-gelation zinxulumene ne-degree yokutshintshwa, i-solution concentration kunye ne-additives. Kwi-hydroxyl alkyl modified derivatives, ii-gel properties zikwanxulumene ne-hydroxyl alkyl modification degree. Kwi-solution concentration ye-low viscosity MC kunye ne-HPmc ingalungiswa isisombululo se-10%-15% concentration, i-medium viscosity MC kunye ne-HPmc zingalungiswa isisombululo se-5%-10% kunye ne-high viscosity MC kunye ne-HPmc zingalungiswa isisombululo se-2%-3% kuphela, kwaye ngesiqhelo i-viscosity ye-cellulose ether nayo ihlelwa ngesisombululo se-1%-2%. Ukusebenza kakuhle kwe-cellulose ether enobunzima obuphezulu be-cellulose ether, uxinzelelo olufanayo lwesisombululo, iipolymers ezahlukeneyo ezinobunzima be-molecular zine-viscosity eyahlukileyo, i-viscosity kunye nobunzima be-molecular zingabonakaliswa ngolu hlobo lulandelayo, [η]=2.92×10-2 (DPn) 0.905, i-DPn liqondo eliphakathi le-polymerization eliphezulu. I-cellulose ether enobunzima obuphantsi be-molecular yokongeza ngaphezulu ukuze kufezekiswe i-viscosity ekujoliswe kuyo. I-viscosity yayo ayixhomekekanga kakhulu kwisantya sokucheba, i-viscosity ephezulu ukuze kufezekiswe i-viscosity ekujoliswe kuyo, ubungakanani obufunekayo ukuze kongezwe kancinci, i-viscosity ixhomekeke ekusebenzeni kakuhle kokuqina. Ke ngoko, ukuze kufezekiswe ukuhambelana okuthile, ubungakanani obuthile be-cellulose ether (uxinzelelo lwesisombululo) kunye ne-viscosity yesisombululo kufuneka kuqinisekiswe. Ubushushu be-gel yesisombululo bunciphe ngokuthe ngqo ngokonyuka koxinzelelo lwesisombululo, kwaye i-gelation yenzeka kubushushu begumbi emva kokufikelela kuxinzelelo oluthile. I-HPmc inoxinzelelo lwe-gel ephezulu kubushushu begumbi.
Ukuhambelana kwayo kunokulungiswa ngokukhetha ubungakanani besuntswana kunye nee-ether ze-cellulose ezinezinga ezahlukeneyo zokuguqulwa. Oku kubizwa ngokuba kukuguqulwa kukungeniswa kweqela le-hydroxyl alkyl kwinqanaba elithile lokutshintshwa kwisakhiwo se-skeleton se-MC. Ngokutshintsha amaxabiso okutshintshwa okunxulumeneyo kwezi mbini ezithatha indawo, oko kukuthi, amaxabiso okutshintshwa okunxulumeneyo kwe-DS kunye ne-MS amaqela e-methoxy kunye ne-hydroxyl. Iipropati ezahlukeneyo ze-cellulose ether ziyafuneka ngokutshintsha amaxabiso okutshintshwa okunxulumeneyo kweentlobo ezimbini ze-substituents.
ulwalamano phakathi kokungqinelana nokuguqulwa. KuMfanekiso 5, ukongezwa kwe-cellulose ether kuchaphazela ukusetyenziswa kwamanzi kwi-mortar kwaye kutshintsha umlinganiselo wamanzi-wokubopha amanzi kunye nesamente, nto leyo ebangela ukuba kube nzima. Okukhona umthamo uphezulu, kokukhona ukusetyenziswa kwamanzi kuphezulu.
Ii-cellulose ethers ezisetyenziswa kwizixhobo zokwakha ezinjengomgubo kufuneka zinyibilike ngokukhawuleza emanzini abandayo kwaye zibonelele ngenkqubo ngendlela efanelekileyo. Ukuba izinga lokucheba elithile lisaguquguquka kwaye lihlala licolloidal, yimveliso engaphantsi komgangatho okanye ekumgangatho ophantsi.
Kukwakho nolwalamano oluhle oluhambelanayo phakathi kokungaguquguquki kodaka lwesamente kunye nomthamo we-cellulose ether, i-cellulose ether inokunyusa kakhulu i-viscosity yodaka, okukhona umthamo umkhulu, kokukhona umphumo ubonakala ngakumbi.
Isisombululo samanzi se-Cellulose ether esine-viscosity ephezulu sine-thixotropy ephezulu, enye yeempawu ze-cellulose ether. Izisombululo zamanzi ze-Mc type polymers zihlala zine-pseudoplastic, i-non-thixotropic fluidity engaphantsi kobushushu bazo be-gel, kodwa iipropati ze-Newtonian flow kwizinga eliphantsi lokucheba. I-Pseudoplasticity iyanda ngokunyuka kobunzima be-molecular okanye i-concentration ye-cellulose ether kwaye ayixhomekekanga kuhlobo kunye ne-degree ye-substituent. Ke ngoko, ii-cellulose ethers ze-viscosity grade efanayo, nokuba yi-MC, i-HPmc okanye i-HEmc, zihlala zibonisa iipropati ezifanayo ze-rheological logama nje i-concentration kunye ne-temperature zihlala zingaguquki. Xa ubushushu busanda, i-structural gel yenziwa kwaye kwenzeka i-hydrotropic flow ephezulu. Ii-Cellulose ethers ezine-concentration ephezulu kunye ne-viscosity ephantsi zibonisa i-thixotropy nangaphantsi kobushushu be-gel. Le propati iluncedo kakhulu ekwakhiweni kwe-building mortar ukulungisa i-flow and flow hanging property yayo. Kufuneka kuchazwe apha ukuba okukhona i-viscosity ye-cellulose ether iphezulu, kokukhona ukugcinwa kwamanzi kuphezulu, kodwa okukhona i-viscosity iphezulu, kokukhona ubunzima be-molecular ye-cellulose ether buphezulu, ukuncipha kokunyibilika kwayo okuhambelanayo, okunefuthe elibi kuxinzelelo lwe-mortar kunye nokusebenza kolwakhiwo. Okukhona i-viscosity iphezulu, kokukhona isiphumo sokutyeba se-mortar sibonakala ngokucacileyo, kodwa asilolwalamano olupheleleyo olulinganayo. I-viscosity ethile ephantsi, kodwa eguquliweyo ye-cellulose ether ekuphuculeni amandla olwakhiwo lwe-mortar emanzi inokusebenza okugqwesileyo ngakumbi, kunye nokwanda kwe-viscosity, ukugcinwa kwamanzi kwe-cellulose ether kuphuculwe.
Ixesha lokuthumela: Matshi-30-2022