Cellulose ether chinhu chakakosha chekuvaka chinowedzera chinowedzera, chinoshandiswa zvakanyanya mukuvaka dhaka, putty poda, coating uye zvimwe zvigadzirwa kuvandudza zvimiro zvemuviri uye kuita kwekuvaka kwechinhu. Izvo zvikamu zvikuru zve cellulose ether zvinosanganisira cellulose basic chimiro uye zvinotsiva zvinounzwa nekugadziriswa kwemakemikari, izvo zvinopa iyo yakasarudzika solubility, thickening, kuchengetedza mvura uye rheological properties.
1. Cellulose basic structure
Cellulose ndeimwe yemapolysaccharides akajairika muchisikigo, anonyanya kutorwa kubva mumiti yemiti. Icho chikamu chepakati che cellulose ether uye chinotarisa chimiro chayo uye zvimiro. Cellulose molecules inoumbwa neglucose units yakabatana ne β-1,4-glycosidic bond kuti iite cheni refu chimiro. Ichi mutsara chimiro chinopa cellulose simba rakawanda uye yakakwira molecular uremu, asi kunyungudika kwayo mumvura hakuna kunaka. Kuti uvandudze kunyungudika kwemvura kweselulosi uye kuenderana nezvinodiwa zvezvinhu zvekuvaka, cellulose inoda kugadziridzwa kemikari.
2. Zvinotsiva-zvinokosha zvinoumba etherification reaction
Izvo zvakasiyana-siyana zve cellulose ether zvinonyanya kuwanikwa nezvinotsiva zvinounzwa ne etherification reaction pakati peboka re hydroxyl (-OH) ye cellulose uye ether makomisheni. Zvakajairika zvinotsiva zvinosanganisira methoxy (-OCH₃), ethoxy (-OC₂H₅) uye hydroxypropyl (-CH₂CHOHCH₃). Kuunzwa kweizvi zvinotsiva kunoshandura kunyungudika, kukora uye kuchengetwa kwemvura kweselulosi. Zvinoenderana neakasiyana akaunzwa anotsiva, cellulose ethers inogona kukamurwa kuita methyl cellulose (MC), hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC) uye mamwe marudzi.
Methyl cellulose (MC): Methyl cellulose inoumbwa nekuunza methyl substituents (-OCH₃) mumapoka ehydroxyl mune cellulose molecule. Iyi cellulose ether ine mvura yakanaka yekunyungudika uye kukora zvivakwa uye inoshandiswa zvakanyanya mudhaka rakaoma, zvinonamira uye machira. MC ine yakanakisa kuchengetedza kwemvura uye inobatsira kuderedza kurasikirwa kwemvura mune zvekuvaka, kuve nechokwadi chekunamatira uye kusimba kwedhaka uye putty poda.
Hydroxyethyl cellulose (HEC): Hydroxyethyl cellulose inoumbwa nekuunza hydroxyethyl substituents (-OC₂H₅), iyo inoita kuti iwedzere kunyungudika nemvura uye munyu. HEC inowanzoshandiswa mumvura-based coatings, latex pendi uye kuvaka additives. Iyo ine yakanakisa thickening uye firimu-inogadzira zvivakwa uye inogona zvakanyanya kuvandudza mashandiro ekuvaka kwezvinhu.
Hydroxypropyl methylcellulose (HPMC): Hydroxypropyl methylcellulose inoumbwa nekuiswa panguva imwechete yehydroxypropyl (-CH₂CHOHCH₃) uye methyl substituents. Rudzi urwu rweselulosi ether runoratidza kuchengetwa kwemvura kwakanakisa, lubricity uye kushanda muzvinhu zvekuvaka senge dhaka rakaoma, zvinonamira mataira, uye ekunze emadziro ekudzivirira masisitimu. HPMC zvakare ine yakanaka tembiricha kuramba uye chando kuramba, saka inogona zvinobudirira kuvandudza mashandiro ezvivakwa zvekuvaka pasi pemamiriro ekunze akanyanya.
3. Kunyungudika kwemvura uye kukora
Kunyungudika kwemvura kwe cellulose ether kunoenderana nerudzi uye chiyero chekutsiviwa kweinotsiva (kureva, nhamba yemapoka ehydroxyl anotsiviwa pane yega yega glucose unit). Iyo yakafanira dhigirii yekutsiva inogonesa cellulose mamorekuru kuti aumbe yunifomu mhinduro mumvura, ichipa zvinhu zvakanaka kukora zvivakwa. Muzvivakwa zvekuvaka, cellulose ethers se thickeners inogona kuwedzera viscosity yedhaka, kudzivirira stratification uye kupatsanurwa kwezvinhu, uye nekudaro kunatsiridza mashandiro ekuvaka.
4. Kuchengeta mvura
Kuchengetwa kwemvura kwe cellulose ether kwakakosha kune kunaka kwezvinhu zvekuvaka. Muzvigadzirwa zvakaita sedhaka uye putty poda, cellulose ether inogona kuumba firimu remvura yakakora pamusoro pechinhu kudzivirira mvura kuti ibude nekukasira, nekudaro ichiwedzera nguva yakavhurika uye kushanda kwechinhu. Izvi zvinoita basa rakakosha pakuvandudza simba rekubatanidza uye kudzivirira kutsemuka.
5. Rheology uye kushanda kwekuvaka
Kuwedzerwa kwe cellulose ether kunonatsiridza zvakanyanya rheological maitiro ezvivakwa zvekuvaka, ndiko kuti, kuyerera uye deformation maitiro ezvigadzirwa pasi pesimba rekunze. Inogona kuvandudza kuchengetwa kwemvura uye lubricity yedhaka, kuwedzera kupomba uye kureruka kwekuvakwa kwezvinhu. Muchigadziro chekuvaka senge spraying, scraping uye masonry, cellulose ether inobatsira kuderedza kupikisa uye kuvandudza kushanda kwekushanda, nekuita kuti yunifomu ipfekedze pasina sagging.
6. Kuenderana uye kuchengetedzwa kwezvakatipoteredza
Cellulose ether inopindirana zvakanaka nezvinhu zvakasiyana-siyana zvekuvaka, kusanganisira simenti, gypsum, lime, etc. Munguva yekuvaka, hazvizoiti zvakashata nezvimwe zvikamu zvemakemikari kuti zvive nechokwadi chekugadzikana kwezvinhu. Uye zvakare, cellulose ether ndeye yakasvibira uye inoshamwaridzana nemamiriro ekunze, iyo inonyanya kutorwa kubva kune yakasikwa chirimwa fiber, haina kukuvadza kune zvakatipoteredza, uye inosangana nekuchengetedzwa kwezvakatipoteredza zvinodiwa zvemazuva ano zvekuvaka.
7. Zvimwe zvakagadziriswa zvigadzirwa
Kuti uwedzere kuvandudza kushanda kwe cellulose ether, zvimwe zvakagadziridzwa zvinoshandiswa zvinogona kuunzwa mukugadzirwa chaiko. Semuyenzaniso, vamwe vagadziri vanozowedzera kudzivirira kwemvura uye kusamira kwemamiriro ekunze kwe cellulose ether nekusanganisa nesilicone, parafini nezvimwe zvinhu. Kuwedzerwa kweizvi zvinongedzo zvakagadziridzwa kazhinji kuzadzisa zvinodiwa zvekushandisa, sekuwedzera anti-permeability uye kusimba mumachira ekunze emadziro kana madhaka asingapindi mvura.
Sechikamu chakakosha muzvigadzirwa zvekuvaka, cellulose ether ine multifunctional properties, kusanganisira kukora, kuchengetedza mvura, uye yakagadziridzwa rheological properties. Zvikamu zvaro zvikuru ndeye cellulose basic chimiro uye zvinotsiva zvakaunzwa ne etherification reaction. Mhando dzakasiyana dze cellulose ethers dzine mashandisirwo akasiyana uye maitiro muzvigadzirwa zvekuvaka nekuda kwekusiyana kwevanotsiva. Cellulose ethers haingogone kuvandudza mashandiro ekuvaka kwezvinhu, asi zvakare inovandudza huwandu hwese uye hupenyu hwebasa rezvivakwa. Naizvozvo, cellulose ethers vane tarisiro yakakura yekushandisa mune zvemazuva ano zvekuvaka.
Nguva yekutumira: Sep-18-2024