Cellulose ether bụ polymer sịntetik mere nke cellulose eke dị ka akụrụngwa site na mgbanwe kemịkalụ. Cellulose ether bụ ihe sitere na cellulose eke, mmepụta cellulose ether na polymer sịntetik dị iche, ihe kachasị mkpa bụ cellulose, ogige polymer eke. N'ihi ihe dị iche iche nke usoro cellulose eke, cellulose n'onwe ya enweghị ike imeghachi omume na onye na-emepụta ihe. Ma mgbe ọgwụgwọ nke ọzịza gị n'ụlọnga, ike hydrogen agbụ n'etiti molekụla agbụ na agbụ e bibiri, na ọrụ nke hydroxyl otu wepụtara n'ime alkali cellulose na mmeghachi omume ike, na cellulose ether nwetara site mmeghachi omume nke etherifying gị n'ụlọnga - OH otu n'ime. - MA ọ bụ otu.
Njirimara nke cellulose ethers na-adabere n'ụdị, ọnụ ọgụgụ na nkesa nke ndị nọchiri anya ya. Nkewa nke cellulose ether na-adaberekwa n'ụdị ihe ngbanwe, ogo nke etherification, solubility na ngwa metụtara ya nwere ike nkewa. Dị ka ụdị ihe ndị na-anọchi anya na agbụ molecular, enwere ike kewaa ya n'ime otu ether na ngwakọta ether. A na-ejikarị MC eme ihe dị ka otu ether, ebe HPmc bụ ether agwakọta. Methyl cellulose ether MC bụ eke cellulose glucose unit na hydroxyl bụ methoxide dochie anya ngwaahịa Ọdịdị usoro [CO H7O2 (OH) 3-H (OCH3) H] X, hydroxypropyl methyl cellulose ether HPmc bụ a unit na hydroxyl bụ akụkụ. nke methoxide dochie, akụkụ ọzọ nke hydroxypropyl dochie ngwaahịa, Usoro nhazi bụ [C6H7O2. (OH) 3-MN (OCH3) M [OCH2CH (OH) CH3] N] X na hydroxyethyl methyl cellulose ether HEmc, nke a na-ejikarị ma na-ere n'ahịa.
Site na solubility nwere ike kewaa n'ime ụdị ionic na ndị na-abụghị ionic. Mmiri-soluble na-abụghị ionic cellulose ether bụ tumadi mejupụtara alkyl ether na hydroxyl alkyl ether abụọ usoro iche iche. A na-eji Ionic Cmc eme ihe n'ụzọ bụ isi na ncha sịntetik, textile, mbipụta, nri na nrigbu mmanụ ala. Ndị na-abụghị ionic MC, HPmc, HEmc na ndị ọzọ a na-ejikarị eme ihe ụlọ, mkpuchi latex, ọgwụ, kemistri kwa ụbọchị na akụkụ ndị ọzọ. Dị ka ihe na-eme ka ihe na-eme ka ọ sie ike, onye na-ejide mmiri, stabilizer, dispersant, onye na-emepụta ihe nkiri.
Cellulose ether njide mmiri
Na mmepụta nke ihe owuwu ụlọ, karịsịa akọrọ agwakọta ngwa agha, cellulose ether na-arụ ọrụ na-apụghị dochie anya, karịsịa na mmepụta nke pụrụ iche ngwa agha (modified ngwa agha), bụ ihe dị mkpa akụkụ.
Ọrụ dị mkpa nke mmiri-soluble cellulose ether na ngwa agha tumadi nwere akụkụ atọ, otu bụ magburu onwe njigide mmiri ike, nke abụọ bụ mmetụta nke ngwa agha agbanwe agbanwe na thixotropy, na nke atọ bụ mmekọrịta na ciment.
Cellulose ether mmiri na-ejigide, dabere na isi nke hydroscopicity, mejupụtara nke ngwa agha, ngwa agha oyi akwa ọkpụrụkpụ, ngwa agha mmiri chọrọ, condensation ihe condensation oge. Njide mmiri nke cellulose ether sitere na solubility na akpịrị ịkpọ nkụ nke cellulose ether n'onwe ya. A maara nke ọma na agbụ mkpụrụ ndụ cellulose, n'agbanyeghị na ha nwere ọnụ ọgụgụ buru ibu nke otu OH nwere mmiri mmiri, na-adịghị edozi na mmiri n'ihi nhazi ha nke ukwuu. Ike hydration nke otu hydroxyl naanị ezughị iji kwụọ ụgwọ maka njikọ njikọ hydrogen intermolecular siri ike na ndị agha van der Waals. Mgbe a na-ewebata ihe ndị nọchiri anya n'ime agbụ molekụla, ọ bụghị naanị ihe ndị na-anọchi anya na-emebi yinye hydrogen, kamakwa a na-agbaji njikọ interchain hydrogen n'ihi ịgbanye ihe ndị nọchiri anya n'etiti agbụ ndị dị n'akụkụ. Ka ibu ihe ndị nọchiri anya ya, ka ebe dị anya n'etiti ụmụ irighiri ihe dị. Ka ukwuu mbibi nke hydrogen bond mmetụta, cellulose lattice mgbasa, ihe ngwọta n'ime cellulose ether na-aghọ mmiri soluble, e guzobere elu viscosity ngwọta. Ka okpomọkụ na-ebili, hydration nke polymer na-ebelata na mmiri dị n'etiti agbụ na-apụ apụ. Mgbe mmetụta mmiri na-ekpo ọkụ zuru ezu, ụmụ irighiri ihe ndị ahụ na-amalite ịgbakọta na gel na-apịaji na netwọk nke akụkụ atọ. Ihe ndị na-emetụta njide mmiri nke ngwa agha gụnyere cellulose ether viscosity, usoro onunu ogwu, urughuru mma na okpomọkụ ọrụ.
Ka viscosity nke cellulose ether dị ukwuu, ka mma na-arụ ọrụ njide mmiri, viscosity nke ngwọta polymer. A na-ekpebikwa ịdị arọ nke molekụla (ogo nke polymerization) nke polymer site na ogologo na morphology nke usoro molekụla nke yinye, na nkesa nke ọnụ ọgụgụ ndị na-anọchi anya na-emetụta kpọmkwem viscosity nso. [eta] = km alfa
Viscosity dị n'ime nke ngwọta polymer
M polymer arọ molekul
α polymer njirimara mgbe niile
K viscosity ngwọta ọnụọgụ
The viscosity nke polymer ngwọta na-adabere na molekụla arọ nke polima. Viscosity na ntinye nke ngwọta cellulose ether metụtara ngwa dị iche iche. Ya mere, onye ọ bụla cellulose ether nwere ọtụtụ dị iche iche viscosity nkọwa, viscosity iwu bụkwa tumadi site nbibi nke alkali cellulose, ya bụ mgbaji nke cellulose molekul yinye iji nweta.
N'ihi na urughuru size, mma urughuru, mma na mmiri njigide. Nnukwu ahụ nke cellulose ether kọntaktị na mmiri, n'elu ozugbo igbari na-etolite a jel kechie ihe iji gbochie mmiri ụmụ irighiri ịnọgide na-abanye n'ime, mgbe ụfọdụ ogologo oge na-akpali akpali enweghị ike evenly gbasasịrị etisasịwo, guzobe a apịtị flocculent ngwọta ma ọ bụ. agglomerate. Solubility nke cellulose ether bụ otu n'ime ihe ndị na-ahọrọ cellulose ether.
Thickening na thixotropy nke cellulose ether
Mmetụta nke abụọ nke cellulose ether - ndim na-adabere na: cellulose ether polymerization degree, ngwọta ngwọta, ọnụ ọgụgụ shear, okpomọkụ na ọnọdụ ndị ọzọ. Ngwongwo gelation nke ngwọta bụ ihe pụrụ iche na alkyl cellulose na ihe ndị gbanwetụrụ. Njirimara Gelation metụtara ogo nke nnọchi, ntinye ngwọta na mgbakwunye. Maka ihe nrụpụta hydroxyl alkyl gbanwetụrụ, ihe gel na-emetụtakwa ogo mgbanwe hydroxyl alkyl. N'ihi na ngwọta ịta nke ala viscosity MC na HPmc nwere ike kwadebere 10% -15% ịta ngwọta, ọkara viscosity MC na HPmc nwere ike kwadebere 5% -10% ngwọta na elu viscosity MC na HPmc nwere ike kwadebere 2% -3% Ngwọta, na-emekarị viscosity nke cellulose ether na-kwadokwa site 1%-2% ngwọta. Elu molecular arọ cellulose ether thickener arụmọrụ, otu ntinye nke ngwọta, dị iche iche molekul arọ polymers nwere dị iche iche viscosity, viscosity na molekụla arọ nwere ike igosipụta dị ka ndị a, [η] = 2.92 × 10-2 (DPn) 0.905, DPn bụ nkezi. polymerization ogo nke elu. Eter cellulose dị arọ dị ala iji gbakwunye ihe iji nweta viscosity ebumnuche. Ya viscosity bụ obere dabere na shiee ọnụego, elu viscosity iji nweta lekwasịrị viscosity, ego dị mkpa iji tinye obere, viscosity dabere na ndim arụmọrụ. Ya mere, iji nweta otu ihe na-agbanwe agbanwe, a ghaghị ijide n'aka na ether cellulose ether (ntụkwasị uche nke ngwọta) na viscosity ngwọta ga-ekwe nkwa. Okpomọkụ gelation nke ihe ngwọta na-ebelata n'ahịrị na mmụba nke ntinye nke ngwọta, na gelation mere na ụlọ okpomọkụ mgbe ọ ruru otu ntinye uche. HPmc nwere mkpokọta gelation dị elu na ụlọ okpomọkụ.
A pụkwara imezi nkwụsi ike site n'ịhọrọ nha nha na cellulose ethers nwere ogo dị iche iche nke mgbanwe. Ihe a na-akpọ mgbanwe bụ iwebata hydroxyl alkyl otu n'ime ogo ụfọdụ nke nnọchi na nhazi ọkpụkpụ nke MC. Site n'ịgbanwe ụkpụrụ ngbanwe nke ndị nnọchi anya abụọ ahụ, ya bụ, ụkpụrụ nnọchi DS na MS nke methoxy na otu hydroxyl. Ngwongwo dị iche iche nke cellulose ether chọrọ site n'ịgbanwe ụkpụrụ ngbanwe nke ụdị abụọ nke nnọchi.
mmekọrịta dị n'etiti nkwụsi ike na mgbanwe. Na eserese 5, mgbakwunye nke cellulose ether na-emetụta oriri mmiri nke ngwa agha ma na-agbanwe oke mmiri na-ejikọta mmiri na ciment, nke bụ mmetụta na-egbuke egbuke. Nke dị elu nke usoro onunu ogwu, ka oriri mmiri na-abawanye.
Cellulose ethers nke a na-eji na ihe owuwu ụlọ ntụ ntụ ga-agbaze ngwa ngwa na mmiri oyi ma nye usoro ahụ n'ụzọ ziri ezi. Ọ bụrụ na ọnụ ọgụgụ shear enyere ka na-efegharị efegharị na colloidal ọ bụ ngwaahịa na-adighi mma ma ọ bụ na-adịghị mma.
Enwekwara mmekọrịta dị mma nke linear n'etiti ciment slurry anọgidesi na usoro onunu ogwu nke cellulose ether, cellulose ether nwere ike dịkwuo viscosity nke ngwa agha, ukwuu na onunu ogwu, pụta ìhè mmetụta.
Cellulose ether aqueous ngwọta na elu viscosity nwere elu thixotropy, nke bụ otu n'ime àgwà nke cellulose ether. Aqueous ngwọta nke ụdị Mc ụdị polymers na-enwekarị pseudoplastic, na-abụghị thixotropic fluidity n'okpuru ha gel okpomọkụ, ma Newtonian eruba Njirimara na ala shiee ọnụego. Pseudoplasticity na-abawanye site na mmụba nke ịdị arọ molekụla ma ọ bụ itinye uche nke ether cellulose ma nweere onwe ya n'ụdị na ogo ngbanwe. Ya mere, cellulose ethers nke otu viscosity ọkwa, ma MC, HPmc ma ọ bụ HEmc, mgbe niile na-egosi otu rheological Njirimara ma ọ bụrụhaala na ịta na okpomọkụ na-anọgide na-adịgide adịgide. Mgbe okpomọkụ na-abawanye, a na-emepụta gel nhazi na oke thixotropic na-eme. Cellulose ethers nwere nnukwu itinye uche na viscosity dị ala na-egosipụta thixotropy ọbụna n'okpuru okpomọkụ gel. Ngwongwo a na-aba uru dị ukwuu maka owuwu ihe owuwu ụlọ iji mezie ihe ọ na-asọ na ihe na-asọpụta. Ọ dị mkpa ka a kọwaa ebe a na elu viscosity nke cellulose ether, mma njigide mmiri, ma elu nke viscosity, nke dị elu ikwu molekụla arọ nke cellulose ether, kwekọrọ ekwekọ Mbelata ya solubility, nke nwere mmetụta ọjọọ na ya. na ngwa agha ịta na ịrụ ọrụ ihe owuwu. Nke dị elu nke viscosity, otú ahụ ka ọ na-apụta ìhè nke ọma mmetụta nke ngwa agha, ma ọ bụghị mmekọrịta zuru oke. Ụfọdụ obere viscosity, ma ether cellulose gbanwetụrụ na imeziwanye ike nhazi nke ngwa agha mmiri na-arụ ọrụ nke ọma karị, na mmụba nke viscosity, cellulose ether mmiri na-ejigide mma.
Oge nzipu: Mar-30-2022