Focus on Cellulose ethers

Mmekọrịta dị n'etiti àgwà cellulose na àgwà ngwa agha

N'ime ngwa agha agwakọtara agwakọta, mgbakwunye nke cellulose ether dị ntakịrị, mana ọ nwere ike imeziwanye arụmọrụ nke ngwa agha mmiri, ọ bụkwa ihe mgbakwunye bụ isi nke na-emetụta arụmọrụ nke ngwa agha. Nhọrọ ezi uche dị na ya nke cellulose ethers nke ụdị dị iche iche, viscosities dị iche iche, nha nha dị iche iche, ọkwa dị iche iche nke viscosity na ego agbakwunyere ga-enwe mmetụta dị mma na nkwalite arụmọrụ nke ngwa ngwa ntụ ntụ. Ka ọ dị ugbu a, ọtụtụ ngwa agha masonry na plasta adịghị arụ ọrụ njide mmiri na-adịghị mma, na slurry mmiri ga-ekewa mgbe nkeji ole na ole guzoro. Njide mmiri bụ ọrụ dị mkpa nke methyl cellulose ether, ọ bụkwa arụmọrụ nke ọtụtụ ndị na-emepụta ihe ọkụkụ na-ekpo ọkụ na-ekpo ọkụ, karịsịa ndị nọ na mpaghara ndịda nke nwere okpomọkụ dị elu, na-aṅa ntị. Ihe ndị na-emetụta mmetụta njigide mmiri nke ngwakọta ngwakọta akọrọ gụnyere ọnụọgụ MC agbakwunyere, viscosity nke MC, ịdị mma nke ihe na okpomọkụ nke gburugburu ebe obibi.

1. Echiche
Cellulose ether bụ polymer sịntetik nke sitere na cellulose eke sitere na mgbanwe kemịkalụ. Cellulose ether bụ ihe sitere na cellulose eke. Ihe mmepụta nke cellulose ether dị iche na polymers sịntetik. Ihe kachasị mkpa ya bụ cellulose, ngwakọta polymer eke. N'ihi ihe dị iche iche nke usoro cellulose eke, cellulose n'onwe ya enweghị ike imeghachi omume na ndị ọrụ etherification. Otú ọ dị, mgbe ọgwụgwọ nke onye na-amụba ihe, a na-ebibi njikọ siri ike hydrogen n'etiti ụdọ molecular na agbụ, na ntọhapụ na-arụ ọrụ nke hydroxyl otu na-aghọ cellulose alkali na-emeghachi omume. Nweta cellulose ether.

Njirimara nke cellulose ethers na-adabere n'ụdị, ọnụ ọgụgụ na nkesa nke ndị nọchiri anya ya. Nkewa nke cellulose ethers na-adaberekwa n'ụdị ihe ngbanwe, ogo nke etherification, solubility na ngwa ngwa metụtara ya. Dị ka ụdị ihe ndị na-anọchi anya na eriri molecular, enwere ike kewaa ya na monoether na ngwakọta ether. MC anyị na-ejikarị bụ monoether, na HPMC bụ ngwakọta ether. Methyl cellulose ether MC bụ ngwaahịa mgbe hydroxyl otu na glucose unit nke eke cellulose dochie methoxy. Ọ bụ ngwaahịa enwetara site na iji otu methoxy dochie akụkụ nke hydroxypropyl na otu akụkụ nke otu hydroxypropyl. Usoro nhazi bụ [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)CH3]n]x Hydroxyethyl methyl cellulose ether HEMC, ndị a bụ ụdị ndị a na-ejikarị na-ere n'ahịa.

N'ihe gbasara solubility, enwere ike kewaa ya na ionic na ndị na-abụghị ionic. Mmiri-soluble na-abụghị ionic cellulose ethers bụ tumadi mejupụtara abụọ usoro nke alkyl ethers na hydroxyalkyl ethers. A na-ejikarị Ionic CMC eme ihe n'ihe ndị sịntetịt, mbipụta textile na akwa akwa, nchọpụta nri na mmanụ. Ndị na-abụghị ionic MC, HPMC, HEMC, wdg bụ ndị a na-ejikarị na ihe owuwu, mkpuchi latex, ọgwụ, kemịkalụ kwa ụbọchị, wdg A na-eji dị ka thickener, mmiri na-ejide mmiri, stabilizer, dispersant na film forming agent.

2. Njide mmiri nke cellulose ether
Njide mmiri nke cellulose ether: Na mmepụta nke ihe owuwu ụlọ, karịsịa akọrọ ntụ ntụ ntụ ntụ, cellulose ether na-arụ ọrụ na-enweghị ike dochie ya, karịsịa na mmepụta nke ngwa agha pụrụ iche (ngwa agha gbanwere), ọ bụ ihe dị mkpa na ihe dị mkpa .

Ọrụ dị mkpa nke mmiri-soluble cellulose ether na ngwa agha tumadi nwere akụkụ atọ, otu bụ magburu onwe mmiri njigide ikike, nke ọzọ bụ mmetụta na agbanwe agbanwe na thixotropy nke ngwa agha, na nke atọ bụ mmekọrịta na ciment. Mmetụta njide mmiri nke cellulose ether na-adabere na mmịpụta mmiri nke oyi akwa nke isi, ihe mejupụtara nke ngwa agha ahụ, ọkpụrụkpụ nke akwa akwa akwa akwa akwa akwa akwa akwa akwa akwa akwa akwa, mmiri chọrọ ngwa ngwa, na oge nhazi nke ihe nhazi. Njide mmiri nke cellulose ether n'onwe ya sitere na solubility na akpịrị ịkpọ nkụ nke cellulose ether n'onwe ya. Dị ka anyị niile maara, ọ bụ ezie na cellulose molecular chain nwere ọnụ ọgụgụ buru ibu nke ukwuu hydratable OH otu, ọ bụghị soluble na mmiri, n'ihi na cellulose Ọdịdị nwere nnukwu ogo nke crystallinity.

Ike hydration nke otu hydroxyl naanị ezughị iji kpuchie njikọ njikọ hydrogen siri ike na ndị agha van der Waals n'etiti ụmụ irighiri ihe. Ya mere, ọ na-aza naanị ma ọ naghị agbaze na mmiri. Mgbe a na-ewebata ihe ngbanwe n'ime agbụ molekụla, ọ bụghị naanị ihe mgbakwunye na-emebi yinye hydrogen, kamakwa a na-emebi njikọ interchain hydrogen n'ihi ịgbanye ihe nọchiri anya n'etiti ụdọ ndị dị n'akụkụ. Ka nnukwu ihe nọchiri anya ya, ka ebe dị anya n'etiti ụmụ irighiri ihe. Nke ka ukwuu na anya. Mmetụta dị ukwuu nke ibibi njikọ hydrogen, cellulose ether na-aghọ mmiri na-agbaze mgbe cellulose lattice gbasaa na ngwọta na-abanye, na-eme ka ngwọta dị elu nke viscosity. Mgbe okpomọkụ na-ebili, hydration nke polymer na-ada mbà, a na-achụpụkwa mmiri n'etiti agbụ. Mgbe mmetụta akpịrị ịkpọ nkụ zuru ezu, ụmụ irighiri ihe ndị ahụ na-amalite ịgbakọta, na-akpụ ihe nhazi netwọk akụkụ atọ wee tụgharịa.

Ihe ndị na-emetụta njide mmiri nke ngwa agha gụnyere viscosity nke cellulose ether, ego a gbakwunyere, ịdị mma nke ihe na okpomọkụ eji eme ihe.

Ka viscosity nke cellulose ether dị ukwuu, otú ahụ ka ọrụ njigide mmiri dị mma. Viscosity bụ oke dị mkpa nke arụmọrụ MC. Ka ọ dị ugbu a, ndị na-emepụta MC dị iche iche na-eji ụzọ na ngwa dị iche iche tụọ viscosity nke MC. Ụzọ ndị bụ isi bụ Haake Rotovisko, Hoppler, Ubbelohde na Brookfield. Maka otu ngwaahịa ahụ, nsonaazụ viscosity a tụrụ site na ụzọ dị iche iche dị nnọọ iche, ụfọdụ nwere ọbụna okpukpu abụọ. Ya mere, mgbe ị na-atụnyere viscosity, a ghaghị ime ya n'etiti otu ụzọ ule, gụnyere okpomọkụ, rotor, wdg.

N'ikwu okwu n'ozuzu, ka viscosity dị elu, ka mma na-ejide mmiri. Otú ọ dị, ka viscosity dị elu na ịdị elu nke ịdị arọ molekụla nke MC, mbelata kwekọrọ na solubility ya ga-enwe mmetụta na-adịghị mma na ike na ịrụ ọrụ nke ngwa agha. Ihe dị elu nke viscosity, otú ahụ ka ọ na-apụta ìhè nke ọma mmetụta na ngwa ngwa, ma ọ bụghị kpọmkwem. Nke dị elu nke viscosity, otú ahụ ka ngwa ngwa mmiri ga-adịkwu viscous, ya bụ, n'oge a na-ewu ihe, a na-egosipụta ya dị ka ịrapara na scraper na nnukwu adhesion na mkpụrụ. Mana ọ naghị enye aka ịbawanye ike nhazi nke ngwa agha mmiri n'onwe ya. N'oge a na-ewu ụlọ, arụ ọrụ mgbochi sag abụghị ihe doro anya. N'ụzọ megidere nke ahụ, ụfọdụ viscosity ọkara na obere viscosity mana methyl cellulose ethers gbanwere nwere ọmarịcha arụmọrụ n'ịkwalite ike nhazi nke ngwa agha mmiri.

Ọnụ ọgụgụ dị ukwuu nke cellulose ether agbakwunyere na ngwa agha ahụ, ka mma na-arụ ọrụ njide mmiri, na elu viscosity, ka mma na-arụ ọrụ njide mmiri.

N'ihe gbasara nha urughuru, ka mma nke urughuru, mma na-ejigide mmiri. Mgbe nnukwu akụkụ nke cellulose ether batara na mmiri, elu ahụ na-agbaze ozugbo ma mepụta gel iji kechie ihe ahụ iji gbochie ụmụ irighiri mmiri na-aga n'ihu na-abanye. Mgbe ụfọdụ, a pụghị ịgbasa ya n'otu n'otu ma gbazee ọbụlagodi mgbe ọ kpalitere ogologo oge, na-akpụ ihe ngwọta flocculent na urukpuru ma ọ bụ agglomeration. Ọ na-emetụta oke mmiri nke cellulose ether, na solubility bụ otu n'ime ihe ndị na-ahọrọ cellulose ether.

Ịdị mma bụkwa ihe ngosi arụmọrụ dị mkpa nke methyl cellulose ether. The MC eji maka akọrọ ntụ ntụ ngwa agha chọrọ ka ntụ ntụ, na obere mmiri ọdịnaya, na fineness na-achọkwa 20% ~ 60% nke urughuru size na-erughị 63um. Ịdị mma na-emetụta solubility nke methyl cellulose ether. Oke MC na-abụkarị granular, ọ dịkwa mfe igbari n'ime mmiri na-enweghị agglomeration, mana ọnụego mgbasa na-adị ngwa ngwa, n'ihi ya, ọ naghị adabara iji mee ihe na ntụ ntụ ntụ. N'ime ngwa ngwa ntụ ntụ akọrọ, MC na-agbasasị n'etiti ihe simenti dị ka nchịkọta, ezigbo filler na ciment, na naanị ezigbo ntụ ntụ nwere ike izere methyl cellulose ether agglomeration mgbe ị na-agwakọta mmiri. Mgbe MC na-agbakwunyere mmiri iji gbazee agglomerates, ọ na-esiri ike ịgbasa na igbari.

Ịdị mma nke MC abụghị naanị ihe efu, kamakwa ọ na-ebelata ike mpaghara nke ngwa agha ahụ. Mgbe a na-etinye ụrọ ntụ ntụ dị otú ahụ n'ebe buru ibu, a ga-ebelata ọsọ ọsọ nke ntụ ntụ ntụ ntụ dị n'ógbè ahụ, na mgbawa ga-apụta n'ihi oge ọgwụgwọ dị iche iche. Maka ngwa agha a na-efesa na-arụ ọrụ, ihe a chọrọ maka ịdị mma dị elu n'ihi oge ngwakọta dị mkpụmkpụ.

Ịdị mma nke MC nwekwara mmetụta ụfọdụ na njide mmiri ya. N'ikwu okwu n'ozuzu, maka methyl cellulose ethers nwere otu viscosity mana ịdị mma dị iche iche, n'okpuru otu ego agbakwunyere, nke kachasị mma na-eme ka mmetụta njide mmiri dịkwuo mma.

Njide mmiri nke MC na-ejikọta ya na okpomọkụ ejiri mee ihe, na njide mmiri nke methyl cellulose ether na-ebelata na mmụba nke okpomọkụ. Otú ọ dị, n'ezie ngwa ngwa, akọrọ ntụ ntụ ngwa agha na-ejikarị na-ekpo ọkụ substrates na elu okpomọkụ (elu 40 degrees) n'ọtụtụ gburugburu ebe obibi, dị ka mpụta mgbidi putty plasta n'okpuru anyanwụ n'oge okpomọkụ, nke na-emekarị accelerates Ịgwọ ciment na hardening. ngwa ngwa ntụ ntụ akọrọ. Mbelata nke njide mmiri na-eduga na mmetụta doro anya na ma arụmọrụ na nkwụsị mgbawa na-emetụta, ọ dịkwa oke mkpa iji belata mmetụta nke ihe okpomọkụ n'okpuru ọnọdụ a.

Ọ bụ ezie na a na-ewere ihe mgbakwunye methyl hydroxyethyl cellulose ether ugbu a dị ka ndị na-ebute ụzọ na mmepe nkà na ụzụ, ndabere ha na okpomọkụ ka ga-eduga n'ịda mbà nke arụmọrụ nke akọrọ ntụ ntụ ntụ. Ọ bụ ezie na ọnụ ọgụgụ nke methyl hydroxyethyl cellulose na-abawanye (usoro okpomọkụ), arụ ọrụ na nkwụsị mgbawa ka enweghị ike igbo mkpa nke iji. Site na ụfọdụ ọgwụgwọ pụrụ iche na MC, dị ka ịba ụba nke etherification, wdg, enwere ike ịnọgide na-enwe mmetụta njigide mmiri na okpomọkụ dị elu, ka o wee nwee ike inye ọrụ ka mma n'okpuru ọnọdụ siri ike.

3. Thickening na thixotropy nke cellulose ether
Thickening na thixotropy nke cellulose ether: Ọrụ nke abụọ nke cellulose ether-thickening mmetụta na-adabere na: ogo nke polymerization nke cellulose ether, ngwọta ngwọta, shiee ọnụego, okpomọkụ na ọnọdụ ndị ọzọ. Ngwongwo gelling nke ihe ngwọta bụ ihe pụrụ iche na alkyl cellulose na ihe ndị gbanwetụrụ. Njirimara gelation metụtara ogo ngbanwe, ntinye ngwọta na ihe mgbakwunye. Maka ihe nrụpụta hydroxyalkyl gbanwetụrụ, njirimara gel na-emetụtakwa ogo mgbanwe nke hydroxyalkyl. N'ihi na ala viscosity MC na HPMC, 10% -15% ngwọta nwere ike kwadebere, ọkara viscosity MC na HPMC nwere ike kwadebere 5% -10% ngwọta, mgbe elu viscosity MC na HPMC nwere ike na-akwadebe 2% -3% ngwọta, na-emekarị. A na-edozikwa nhazi nke viscosity nke cellulose ether site na 1%-2% ngwọta.

Ether cellulose dị arọ nke dị elu nwere arụmọrụ njupụta dị elu. N'otu ngwọta ntinye uche ahụ, polymers nwere ịdị arọ dị iche iche nwere viscosities dị iche iche. Ọkwa dị elu. Enwere ike nweta viscosity ebumnuche naanị site n'ịgbakwụnye nnukwu ether cellulose dị arọ dị ala. Viscosity ya nwere ntakịrị ịdabere na ọnụ ọgụgụ shear, na viscosity dị elu na-erute viscosity lekwasịrị anya, na ihe mgbakwunye a chọrọ dị ntakịrị, na viscosity na-adabere na nrụpụta ọrụ. Ya mere, iji nweta ihe na-agbanwe agbanwe, a ghaghị ijide n'aka na ether cellulose ether (ntụkwasị uche nke ngwọta) na viscosity ngwọta ga-ekwe nkwa. The gel okpomọkụ nke ngwọta na-ebelata linearly na-abawanye nke ịta nke ihe ngwọta, na gels na ụlọ okpomọkụ mgbe eru a ụfọdụ ịta. The gelling ịta ahụhụ nke HPMC dịtụ elu na ụlọ okpomọkụ.

Enwere ike ịhazi nkwekọ site na ịhọrọ nha nha na ịhọrọ cellulose ethers nwere ogo mgbanwe dị iche iche. Ihe a na-akpọ mgbanwe bụ iwebata ụfọdụ ngbanwe nke otu hydroxyalkyl na nhazi ọkpụkpụ nke MC. Site n'ịgbanwe ụkpụrụ ngbanwe nke ndị nnọchi anya abụọ ahụ, ya bụ, ụkpụrụ nnọchi DS na ms nke ndị otu methoxy na hydroxyalky nke anyị na-ekwukarị. Enwere ike nweta ihe dị iche iche chọrọ ịrụ ọrụ nke cellulose ether site n'ịgbanwe ụkpụrụ nnọchi anya nke ihe abụọ a nọchiri anya ya.

Mmekọrịta dị n'etiti nkwụsi ike na mgbanwe: mgbakwunye cellulose ether na-emetụta mmiri oriri nke ngwa agha, na-agbanwe mmiri na-ejikọta mmiri na ciment bụ mmetụta na-eme ka ọ dịkwuo elu, nke dị elu nke usoro onunu ogwu, na-abawanye oriri mmiri.

Cellulose ethers nke a na-eji na ihe owuwu ụlọ ntụ ntụ ga-agbaze ngwa ngwa na mmiri oyi ma nye usoro kwesịrị ekwesị maka usoro ahụ. Ọ bụrụ na enyere ya ọnụ ọgụgụ shear, ọ ka na-aghọ flocculent na colloidal block, nke bụ ngwaahịa na-adịghị mma ma ọ bụ na-adịghị mma.

Enwekwara mmekọrịta dị mma n'ahịrị n'etiti nkwụsi ike nke cement ciment na usoro nke cellulose ether. Cellulose ether nwere ike ịbawanye viscosity nke ngwa agha. Ka usoro onunu ogwu buru ibu, ka mmetụta ya pụta ìhè. Nnukwu viscosity cellulose ether aqueous ngwọta nwere thixotropy dị elu, nke bụkwa isi njirimara cellulose ether. Aqueous ngwọta nke MC 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 ịdị arọ molekụla ma ọ bụ itinye uche nke cellulose ether, n'agbanyeghị ụdị nnọchi na ogo nke nnọchi. Ya mere, cellulose ethers nke otu viscosity ọkwa, n'agbanyeghị MC, HPMC, HEMC, ga-mgbe niile na-egosi otu rheological Njirimara ma ọ bụrụhaala na ịta na okpomọkụ na-na-anọgide na-adịgide adịgide.

A na-emepụta gels ihe owuwu mgbe a na-ebuli okpomọkụ elu, na oke thixotropic na-eme. Nnukwu ntinye uche na obere viscosity cellulose ethers na-egosi thixotropy ọbụna n'okpuru gel okpomọkụ. Ngwongwo a bara uru nke ukwuu maka ngbanwe nke larịị na sagging na-ewu ụlọ mgbidi. Ọ dị mkpa ka a kọwaa ebe a na elu viscosity nke cellulose ether, mma njigide mmiri, ma elu nke viscosity, elu nke ikwu molekụla arọ nke cellulose ether, na kwekọrọ ekwekọ mbelata ya solubility, nke nwere mmetụta ọjọọ. na ngwa agha ịta na ịrụ ọrụ ihe owuwu. Nke dị elu nke viscosity, otú ahụ ka ọ na-apụta ìhè nke ọma mmetụta na ngwa agha ahụ, ma ọ bụghị kpamkpam. Ụfọdụ ọkara na viscosity dị ala, mana cellulose ether gbanwetụrụ nwere arụmọrụ ka mma n'ịkwalite ike nhazi nke ngwa agha mmiri. Site na mmụba nke viscosity, njigide mmiri nke cellulose ether na-akawanye mma.

4. Nkwụghachi azụ nke cellulose ether
Mbelata nke cellulose ether: Ọrụ nke atọ nke cellulose ether bụ igbu oge usoro hydration nke ciment. Cellulose ether na-enye ngwa agha nwere ihe bara uru dị iche iche, ma na-ebelata okpomọkụ nke mbụ nke ciment ma na-egbu oge usoro hydration ike nke ciment. Nke a adịghị mma maka iji ngwa agha na mpaghara oyi. A na-akpata mmetụta nkwụghachi azụ a site na ntinye nke cellulose ether molecules na ngwaahịa hydration dị ka CSH na ca (OH) 2. N'ihi mmụba nke viscosity nke ngwọta pore, cellulose ether na-ebelata mmegharị nke ion na ngwọta, si otú ahụ na-egbu oge usoro hydration.

N'ịdị elu nke cellulose ether na ihe gel ịnweta, ka mmetụta nke igbu oge hydration na-apụtawanye ìhè. Cellulose ether ọ bụghị nanị na-egbu oge nhazi, kamakwa ọ na-egbu oge usoro siri ike nke usoro ciment mortar. Mmetụta retarding nke cellulose ether na-adabere ọ bụghị nanị na ntinye ya na sistemụ ịnweta gel, kamakwa na usoro kemịkal. N'ịdị elu nke methylation nke HEMC, ka mma na-ebelata mmetụta nke cellulose ether. Oke nke nnọchi hydrophilic na nnọchi na-abawanye mmiri Mmetụta azụ azụ ka siri ike. Otú ọ dị, viscosity nke cellulose ether enwechaghị mmetụta na ciment hydration kinetics.

Site na mmụba nke cellulose ether ọdịnaya, nhazi oge nke ngwa agha na-abawanye nke ukwuu. Enwere ezigbo mmekọrịta na-adịghị n'ịntanetị n'etiti mmalite mmalite oge nke ngwa agha na ọdịnaya nke cellulose ether, yana ezigbo njikọ dị n'etiti oge nhazi ikpeazụ na ọdịnaya nke cellulose ether. Anyị nwere ike ijikwa oge arụ ọrụ nke ngwa agha ahụ site n'ịgbanwe ọnụọgụ cellulose ether.


Oge nzipu: Mar-22-2023
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