Nonionic cellulose ether na polymer ciment

Dị ka ihe mgbakwunye dị mkpa na ciment polymer, nonionic cellulose ether enwetawo nlebara anya na nyocha dị ukwuu. Dabere na akwụkwọ ndị dị mkpa n'ụlọ na ná mba ọzọ, a na-atụle iwu na usoro nke na-abụghị ionic cellulose ether ether modified ciment mortar si akụkụ nke ụdị na nhọrọ nke na-abụghị ionic cellulose ether, mmetụta ya na anụ ahụ Njirimara nke polymer ciment, mmetụta ya na micromorphology na akụrụngwa akụrụngwa, na adịghị ike nke nyocha ugbu a ka etinyere n'ihu. Ọrụ a ga-akwalite ntinye nke cellulose ether na ciment polymer.

Isi okwu: nonionic cellulose ether, polymer ciment, anụ ahụ Njirimara, n'ibu Njirimara, microstructure

1. Nchịkọta

N'ịbawanye ọchịchọ na ịrụ ọrụ chọrọ nke ciment polymer na ụlọ ọrụ mmepụta ihe, ịgbakwunye ihe mgbakwunye na mgbanwe ya aghọwo ebe a na-eme nchọpụta, n'etiti nke a na-eji cellulose ether eme ihe n'ihi mmetụta ya na ciment mortar mmiri njide, ndim, retarding, ikuku. were gabazie. N'akwụkwọ a, a na-akọwa ụdị cellulose ether, mmetụta dị na anụ ahụ na ihe arụ ọrụ nke ciment polymer na micromorphology nke ciment polymer, nke na-enye ntụaka usoro maka ntinye nke cellulose ether na ciment polymer.

2. Ụdị nonionic cellulose ether

Cellulose ether bụ ụdị ngwakọta polymer nwere usoro ether nke sitere na cellulose. E nwere ọtụtụ ụdị cellulose ether, nke nwere mmetụta dị ukwuu na njirimara nke ihe ndị dabeere na ciment ma sie ike ịhọrọ. Dị ka usoro kemịkalụ nke ndị nnọchi anya, enwere ike kewaa ha n'ime anionic, cationic na nonionic ethers. Nonionic cellulose ether na n'akụkụ yinye nnọchi nke H, cH3, c2H5, (cH2cH20) nH, [cH2cH (cH3) 0] nH na ndị ọzọ na-abụghị dissociable otu bụ nke a na-ejikarị na ciment, ndị nnọchiteanya na-ahụkarị bụ methyl cellulose ether, hydroxypropyl methyl. cellulose ether, hydroxyethyl methyl cellulose ether, hydroxyethyl cellulose ether na na. Ụdị dị iche iche nke cellulose ethers nwere mmetụta dị iche iche na nhazi oge ciment. Dị ka akwụkwọ akụkọ ndị gara aga si kwuo, HEC nwere ikike nkwụsịtụ siri ike maka ciment, HPMc na HEMc sochiri ya, Mc nwere nke kachasị njọ. Maka otu ụdị cellulose ether, molecular arọ ma ọ bụ viscosity, methyl, hydroxyethyl, hydroxypropyl ọdịnaya nke ndị a dị iche iche, ya retarding mmetụta dịkwa iche iche. N'ikwu okwu n'ozuzu, ka viscosity na-abawanye na ọdịnaya nke ndị na-adịghị ekewapụ, na-akawanye njọ ike igbu oge. Ya mere, n'ime usoro mmepụta ihe n'ezie, dị ka ihe achọrọ nke coagulation ngwa agha azụmahịa, enwere ike ịhọrọ ọdịnaya otu kwesịrị ekwesị nke cellulose ether. Ma ọ bụ na mmepụta nke cellulose ether n'otu oge ahụ, gbanwee ọdịnaya nke otu ndị na-arụ ọrụ, mee ka ọ mezuo ihe achọrọ nke ngwa agha dị iche iche.

3,mmetụta nke nonionic cellulose ether na ihe anụ ahụ nke ciment polymer

3.1 Obere coagulation

Iji gbatịa hydration hardening oge simenti, nke mere na ọhụrụ mbuaha ngwa agha na ogologo oge na-anọgide na plastic, nke mere ka ịgbanwe ntọala oge nke ọhụrụ agwakọta ngwa agha, mma ya operability, na-emekarị tinye retarder na ngwa agha, na-abụghị- ionic cellulose ether adabara polymer ciment bụ nkịtị retarder.

Mmetụta retarding nke nonionic cellulose ether na ciment na-emetụtakarị ụdị nke ya, viscosity, usoro onunu ogwu, ihe dị iche iche nke ciment mineral na ihe ndị ọzọ. Pourchez J et al. gosiri na ọkwa dị elu nke cellulose ether methylation dị elu, na-akawanye njọ mmetụta retarding, ebe ịdị arọ nke cellulose ether na hydroxypropoxy ọdịnaya nwere mmetụta na-adịghị ike na retarding nke ciment hydration. Na mmụba nke viscosity na doping ego nke na-abụghị ionic cellulose ether, adsorption oyi akwa n'elu nke simenti irighiri na-agbatịa, na mbụ na ikpeazụ ntọala oge nke ciment na-agbatị, na retarding mmetụta bụ ihe doro anya. Nnyocha egosiwo na ntọhapụ okpomọkụ mbụ nke ciment slurries nwere ihe dị iche iche HEMC dị ihe dịka 15% dị ala karịa nke ciment slurries dị ọcha, ma ọ dịghị ihe dị iche iche dị ịrịba ama na usoro hydration na-esote. Singh NK et al. gosiri na na mmụba nke HEc doping ego, hydration okpomọkụ ntọhapụ nke gbanwetụrụ simenti ngwa agha gosiri a na-emekarị nke mbụ na-amụba na mgbe ahụ ibelata, na HEC ọdịnaya mgbe eru kacha hydration okpomọkụ ntọhapụ metụtara ọgwụgwọ afọ.

Tụkwasị na nke ahụ, a chọpụtara na mmetụta nkwụsị nke nonionic cellulose ether nwere njikọ chiri anya na nchịkọta ciment. Peschard et al. chọpụtara na ka ọdịnaya nke tricalcium aluminate (C3A) dị na simenti dị ala, ka a na-apụtawanye ìhè mmetụta azụ azụ nke cellulose ether. schmitz L et al. kwenyere na nke a sitere na ụzọ dị iche iche nke cellulose ether na hydration kinetics nke tricalcium silicate (C3S) na tricalcium aluminate (C3A). Cellulose ether nwere ike ibelata mmeghachi omume mmeghachi omume na oge osooso nke C3S, ebe maka C3A, ọ nwere ike ịgbatị oge ntinye, ma mesịa gbuo oge siri ike na usoro siri ike nke ngwa agha.

E nwere echiche dị iche iche na usoro nke na-abụghị ionic cellulose ether na-egbu oge ciment hydration. Silva et al. Liu kwenyere na iwebata cellulose ether ga-eme ka viscosity nke ngwọta pore na-abawanye, si otú a na-egbochi mmegharị nke ion ma na-egbu oge condensation. Agbanyeghị, Pourchez et al. kwenyere na enwere mmekọrịta doro anya n'etiti igbu oge nke cellulose ether na hydration ciment na viscosity nke ciment slurry. Ozizi ọzọ bụ na mmetụta azụ azụ nke cellulose ether nwere njikọ chiri anya na mmebi alkali. Polysaccharides na-agbada ngwa ngwa iji mepụta hydroxyl carboxylic acid nke nwere ike igbu oge hydration nke ciment n'okpuru ọnọdụ alkaline. Otú ọ dị, ọmụmụ achọpụtala na cellulose ether dị nnọọ kwụsiri ike n'okpuru ọnọdụ alkaline ma na-eweda ya ntakịrị, na mmebi ahụ na-enwe mmetụta dị nta na igbu oge nke ciment hydration. Ka ọ dị ugbu a, echiche na-agbanwe agbanwe bụ na ọ bụ mgbasa ozi na-ebute mmetụta azụ azụ. Kpọmkwem, otu hydroxyl dị n'elu molekụla cellulose ether bụ acidic, ca (0H) na usoro ciment hydration, na akụkụ ndị ọzọ ịnweta bụ alkaline. N'okpuru ọrụ synergistic nke hydrogen bonding, complexing na hydrophobic, acidic cellulose ether molecule ga-adsorbed n'elu nke alkaline ciment irighiri na hydration ngwaahịa. Tụkwasị na nke ahụ, a na-emepụta ihe nkiri dị mkpa n'elu ya, nke na-egbochi ọganihu nke ịnweta akụkụ kristal a ma na-egbu oge hydration na ntọala nke ciment. Ka ikike mgbasa ozi siri ike dị n'etiti ngwaahịa hydration ciment na cellulose ether, otú ahụ ka ọ na-apụta ìhè karị n'egbughị oge hydration nke ciment. N'otu aka ahụ, nha nke mgbochi stric na-arụ ọrụ dị mkpa na ikike mgbasa ozi, dị ka obere mgbochi stric nke hydroxyl otu, acidity ya siri ike, adsorption dịkwa ike. N'aka nke ọzọ, ikike adsorption na-adaberekwa n'ihe mejupụtara ngwaahịa hydration nke ciment. Pourchez et al. chọpụtara na cellulose ether na-adị mfe adsorbed n'elu nke hydration ngwaahịa dị ka ca (0H) 2, csH gel na calcium aluminate hydrate, ma ọ dịghị mfe adsorbed site ettringite na unhydrated oge. Ọmụmụ Mullert gosikwara na cellulose ether nwere mgbasa ozi siri ike na c3s na ngwaahịa hydration ya, ya mere hydration nke usoro silicate na-egbu oge nke ukwuu. Mgbasa ozi nke ettringite dị obere, mana nhazi ettringite egbuola oge nke ukwuu. Nke a bụ n'ihi na igbu oge na ettringite na-emetụta ca2 + itule na ngwọta, nke bụ n'ihu nke igbu oge nke cellulose ether na silicate hydration.

3.2 Nchekwa mmiri

Mmetụta ọzọ dị mkpa mgbanwe nke cellulose ether na ngwa ngwa ciment bụ ịpụta dị ka onye na-ejigide mmiri, nke nwere ike igbochi mmiri mmiri dị na ngwa ngwa mmiri na-esi na ya pụta n'oge na-adịghị anya ma ọ bụ na-etinye uche ya na isi, na-egbu oge hydration nke ciment mgbe ọ na-agbatị oge ọrụ. ngwa ngwa mmiri dị mmiri, ka e wee hụ na e nwere ike ịsụ ngwa ngwa ndị dị gịrịgịrị, a pụrụ ịgbasa ngwa ngwa a kpụrụ akpụ, ma dị mfe ịmịkọrọ ngwa agha, ọ dịghị mkpa ka ọ bụrụ tupu mmiri.

Ikike ijide mmiri nke cellulose ether nwere njikọ chiri anya na viscosity, usoro onunu ogwu, ụdị na ọnọdụ okpomọkụ. Ọnọdụ ndị ọzọ bụ otu ihe ahụ, ka viscosity nke cellulose ether dịkwuo mma, ka mma na-eme ka mmiri na-ejide mmiri, obere ihe nke cellulose ether nwere ike ime ka mmiri na-ejide mmiri nke ngwa agha ka mma; Maka otu cellulose ether, ọnụ ọgụgụ dị elu nke agbakwunyere, na-eme ka ọnụ ọgụgụ dị elu nke mmiri na-eme ka mmiri gbanwee, ma enwere uru dị mma, karịa nke njide mmiri na-abawanye nwayọọ nwayọọ. Maka ụdị cellulose ether dị iche iche, e nwekwara ọdịiche dị na njide mmiri, dị ka HPMc n'okpuru otu ọnọdụ karịa Mc ka mma nke mmiri. Tụkwasị na nke ahụ, ọrụ njigide mmiri nke cellulose ether na-ebelata na mmụba nke ọnọdụ okpomọkụ.

A na-ekwenyekarị na ihe kpatara cellulose ether ji arụ ọrụ nke njide mmiri bụ n'ihi na 0H na molecule na 0 atom na ether bond ga-ejikọta ya na mkpụrụ ndụ mmiri iji mepụta njikọ hydrogen, nke mere na mmiri efu na-ejikọta ya. mmiri, ka o wee rụọ ọrụ dị mma nke njide mmiri; A na-ekwenyekwa na cellulose ether macromolecular chain na-arụ ọrụ mgbochi na mgbasa nke mkpụrụ ndụ mmiri, ka o wee nwee ike ịchịkwa evaporation mmiri nke ọma, iji nweta njigide mmiri dị elu; Pourchez J rụrụ ụka na cellulose ether nwetara mmetụta njide mmiri site na melite rheological Njirimara nke ọhụrụ agwakọta ciment slurry, Ọdịdị nke porous netwọk na e guzobere cellulose ether film nke gbochiri mgbasa nke mmiri. Laetitia P et al. kwenyekwara na rheological onwunwe nke ngwa agha bụ isi ihe, ma kwenye na viscosity abụghị naanị ihe na-ekpebi ezigbo njigide mmiri nke ngwa agha. Ọ bụ ihe kwesịrị ịrịba ama na ọ bụ ezie na ether cellulose nwere ezigbo njigide mmiri, ma ya gbanwetụrụ ike ciment ngwa agha mmiri absorption ga-ebelata, ihe kpatara ya bụ na cellulose ether na ngwa agha film, na na ngwa agha ọnụ ọgụgụ buru ibu nke obere mechiri emechi pores, igbochi. ngwa agha dị n'ime capillary.

3.3 Na-agba ọsọ

Nkwekọrịta nke ngwa agha bụ otu n'ime ndenye dị mkpa iji tụọ arụmọrụ ya. A na-ebutekarị cellulose ether iji mee ka ọ dịkwuo mma. “Nkwenye” na-anọchi anya ikike nke ngwa agha agwakọtara ọhụrụ ịfe na nrụrụ n'okpuru ọrụ ike ndọda ma ọ bụ ike mpụga. Ngwongwo abuo nke ndina na njigide mmiri na-akwado ibe ha. Ịgbakwunye ihe kwesịrị ekwesị ego nke cellulose ether nwere ike ọ bụghị nanị melite mmiri njigide arụmọrụ nke ngwa agha, hụ na-eji ire ụtọ ewu, ma na-amụba agbanwe agbanwe nke ngwa agha, budata dịkwuo mgbochi dispersion ikike nke ciment, melite nkekọ arụmọrụ n'etiti ngwa agha na matrix, na belata mkpọda ngwa ngwa.

The ndim mmetụta nke cellulose ether tumadi sitere na ya viscosity, ukwuu na viscosity, mma ndị ndim mmetụta, ma ọ bụrụ na viscosity bụ oke ibu, ọ ga-ebelata fluidity nke ngwa agha, na-emetụta ewu. Ihe ndị na-emetụta mgbanwe viscosity, dị ka ịdị arọ molecular (ma ọ bụ ogo nke polymerization) na ntinye nke cellulose ether, ngwọta ngwọta, ọnụ ọgụgụ shear, ga-emetụta njedebe ikpeazụ.

Usoro ihe na-eme ka cellulose ether na-esiwanye ike na-esite na hydration na njikọ dị n'etiti ụmụ irighiri ihe. N'otu aka ahụ, ụdọ polymer nke cellulose ether dị mfe ịmepụta njikọ hydrogen na mmiri na mmiri, njikọ hydrogen na-eme ka ọ nwee nnukwu hydration; N'aka nke ọzọ, mgbe cellulose ether na-agbakwunyere na ngwa agha ahụ, ọ ga-amịkọrọ mmiri dị ukwuu, nke mere na ụda nke ya na-agbasawanye nke ukwuu, na-ebelata ohere nke ihe ndị dị n'efu, n'otu oge cellulose ether molecular chains na-ejikọta ibe ha. iji mepụta usoro netwọk dị n'akụkụ atọ, a na-agbakọta akụkụ ngwa agha nke, ọ bụghị n'efu. N'ikwu ya n'ụzọ ọzọ, n'okpuru omume abụọ a, a na-eme ka viscosity nke usoro ahụ dịkwuo mma, si otú a na-enweta mmetụta siri ike chọrọ.

4. Mmetụta nke nonionic cellulose ether na morphology na pore Ọdịdị nke polymer ciment.

Dị ka a na-ahụ n'elu, ether cellulose na-abụghị ionic na-arụ ọrụ dị mkpa na ciment polymer, na mgbakwunye ya ga-emetụta microstructure nke ciment dum. Nsonaazụ na-egosi na ndị na-abụghị ionic cellulose ether na-emekarị ka porosity nke ciment ngwa agha, na ọnụ ọgụgụ nke pores na size nke 3nm ~ 350um na-abawanye, n'etiti nke ọnụ ọgụgụ nke pores na nso nke 100nm ~ 500nm na-abawanye. Mmetụta dị na nhazi pore nke ụrọ ciment nwere njikọ chiri anya na ụdị na viscosity nke na-abụghị ionic cellulose ether agbakwunyere. Ou Zhihua et al. kwenyere na mgbe viscosity bụ otu ihe ahụ, porosity nke ciment mortar nke HEC gbanwere dị ntakịrị karịa nke HPMc na Mc gbakwunyere dị ka ndị na-agbanwe agbanwe. Maka otu cellulose ether, nke nta nke viscosity, na-ebelata porosity nke ciment simenti gbanwere. Site n'ịmụ mmetụta nke HPMc na oghere nke bọọdụ mkpuchi ciment, Wang Yanru et al. chọpụtara na mgbakwunye nke HPMC anaghị agbanwe porosity nke ukwuu, mana ọ nwere ike belata oghere nke ukwuu. Agbanyeghị, Zhang Guodian et al. chọpụtara na ka ọdịnaya HEMc na-abawanye, otú ahụ ka ọ na-apụta ìhè na mmetụta nke pore nhazi nke ciment slurry. Mgbakwunye nke HEMc nwere ike ịbawanye porosity nke ukwuu, mkpokọta pore olu na nkezi pore radius nke ciment slurry, ma kpọmkwem n'elu ebe nke pore na-ebelata, na ọnụ ọgụgụ nke nnukwu capillary pores ibu karịa 50nm na dayameta na-abawanye nke ukwuu, na pores ewepụtara. bụ tumadi mechiri emechi pores.

A tụlere mmetụta nke nonionic cellulose ether na nhazi usoro nke cement slurry pore structure. Achọpụtara na mgbakwunye nke cellulose ether bụ isi gbanwere njirimara nke usoro mmiri mmiri. N'otu aka ahụ, mmiri mmiri frasi elu esemokwu mbelata, na-eme ka ọ dị mfe na-etolite egosipụta na ciment ngwa agha, na ga-ebelata mmiri mmiri na-adọ drainage na afụ mgbasa, nke mere na obere egosipụta na-esi ike ikpokọta n'ime nnukwu egosipụta na mwepu, otú efu. na-abawanye nke ukwuu; N'aka nke ọzọ, viscosity nke mmiri mmiri mmiri na-abawanye, nke na-egbochikwa drainage, mgbasa nke afụ na afụ ọnụ, na-eme ka ikike ịkwado egosipụta. Ya mere, mmetụta mode nke cellulose ether na pore size nkesa nke ciment ngwa agha nwere ike nweta: na pore size nso nke ihe karịrị 100nm, afụ nwere ike ewebata site ibelata elu esemokwu nke mmiri mmiri na-adọ, na afụ mgbasa nwere ike igbochi site. ịba ụba viscosity mmiri; na mpaghara 30nm ~ 60nm, ọnụ ọgụgụ nke pores na mpaghara nwere ike imetụta site na igbochi njikọ nke obere egosipụta.

5. Mmetụta nke nonionic cellulose ether na-arụ ọrụ nke simenti polymer

Ihe eji arụ ọrụ nke ciment polymer nwere njikọ chiri anya na morphology ya. Na mgbakwunye nke nonionic cellulose ether, porosity na-abawanye, bụ nke ga-enwe mmetụta ọjọọ na ike ya, karịsịa ike mkpakọ na ike mgbanwe. Mbelata ike mkpakọ nke ụrọ ciment dị nnọọ ukwuu karịa ike mgbanwe. Ou Zhihua et al. mụrụ mmetụta nke ụdị dị iche iche nke na-abụghị ionic cellulose ether na n'ibu Njirimara nke simenti ngwa agha, na chọpụtara na ike nke cellulose ether gbanwetụrụ siment ngwa agha dị ala karịa nke dị ọcha ciment ngwa agha, na kasị ala 28d mkpakọ ike bụ naanị 44.3% nke dị ọcha ciment slurry. The compressive ike na mgbanwe ike nke HPMc, HEMC na MC cellulose ether gbanwetụrụ yiri, mgbe ike mkpakọ na ike mgbanwe nke HEc gbanwetụrụ ciment slurry n'afọ ọ bụla dị nnọọ elu. Nke a nwere njikọ chiri anya na viscosity ha ma ọ bụ ịdị arọ molekụla, ka viscosity ma ọ bụ ịdị arọ nke cellulose ether dị elu, ma ọ bụ ka ọrụ elu dị elu, na-ebelata ike nke ngwa ngwa ciment a gbanwere.

Otú ọ dị, egosiwokwa na nonionic cellulose ether nwere ike ime ka ike nkwụsị, mgbanwe na ịdị n'otu nke ciment mortar. Huang Liangen et al. chọpụtara na, n'ụzọ megidere iwu mgbanwe nke ike mkpakọ, ike ịkwa akwa na ike nkwụsị nke slurry mụbara na mmụba nke ọdịnaya nke cellulose ether na ngwa ngwa ciment. Nyocha nke ihe kpatara ya, mgbe mgbakwunye nke cellulose ether, na polymer emulsion ọnụ na-etolite a ọnụ ọgụgụ buru ibu nke ok polymer film, ukwuu mma mgbanwe nke slurry, na ciment hydration ngwaahịa, unhydrated ciment, fillers na ihe ndị ọzọ jupụtara na fim a. , iji hụ na ike nkwụsị nke usoro mkpuchi.

Iji melite arụmọrụ nke na-abụghị ionic cellulose ether gbanwetụrụ polymer ciment, melite anụ ahụ Njirimara nke ciment ngwa agha n'otu oge, adịghị budata ibelata ya n'ibu Njirimara, na-emebu omume bụ dakọtara cellulose ether na ndị ọzọ admixtures, gbakwunyere na. ngwa simenti. Li Tao-wen et al. chọpụtara na ihe mgbakwunye ngwakọta mejupụtara cellulose ether na polymer gluu ntụ ntụ ọ bụghị naanị na-eme ka ike na-ehulata na ike mkpakọ nke ngwa agha, nke mere na cohesiveness na viscosity nke ngwa ngwa ciment na-adabara maka ihe mkpuchi mkpuchi, ma mekwara ka njigide mmiri dịkwuo mma. ikike nke ngwa agha ma e jiri ya tụnyere otu cellulose ether. Xu Qi et al. agbakwunyere ntụ ntụ slag, onye na-ebelata mmiri na HEMc, wee chọpụta na mmiri na-ebelata mmiri na ntụ ntụ ịnweta nwere ike ime ka njupụta nke ngwa agha dị elu, belata ọnụ ọgụgụ nke oghere, ka ọ dịkwuo mma na ike na-agbanwe agbanwe nke ngwa agha. HEMc nwere ike ịbawanye ike njigide nke ngwa agha, mana ọ dịghị mma maka ike mkpakọ na modulus nke ngwa agha. Yang Xiaojie et al. chọpụtara na enwere ike ibelata mgbawa rọba plastik nke simenti ngwa ngwa mgbe agwakọta HEMc na PP fiber.

6. Nkwubi okwu

Nonionic cellulose ether na-arụ ọrụ dị mkpa na simenti polymer, nke nwere ike imeziwanye ihe anụ ahụ (gụnyere coagulation na-azụ azụ, njigide mmiri, ịgbara), morphology microscopic na ihe eji arụ ọrụ nke ngwa ngwa ciment. Emeela ọtụtụ ọrụ na ngbanwe nke ihe ndị sitere na ciment site na cellulose ether, ma a ka nwere nsogbu ụfọdụ chọrọ ọmụmụ ihe ọzọ. Dịka ọmụmaatụ, na ngwa injinia bara uru, a na-akwụ obere nlebara anya na rheology, njirimara deformation, nkwụsi ike olu na ịdịte aka nke ihe ndị sitere na ciment gbanwere, na enwebeghị mmekọrịta kwekọrọ na ya na cellulose ether agbakwunyere. Nnyocha na usoro mbugharị nke cellulose ether polymer na ngwaahịa hydration ciment na mmeghachi omume hydration ka ezughị oke. Usoro ihe omume na usoro nke ihe mgbakwunye ihe mejupụtara cellulose ether na admixtures ndị ọzọ adịghị edozi nke ọma. Ngwakọta ngwakọta nke cellulose ether na ihe ndị a na-emesi ike dị ka eriri iko emebeghị nke ọma. Ihe ndị a niile ga-abụ ebe a ga-elekwasị anya na nyocha n'ọdịnihu iji nye nduzi usoro iwu maka imeziwanye arụmọrụ nke ciment polymer.