Inkomoko ya selile ikorwa na esterification cyangwa etherification ya hydroxyl mumatsinda ya selile ya polymer hamwe na reagent ya chimique.Ukurikije imiterere yimiterere yibicuruzwa byabyitwayemo, ibikomoka kuri selile birashobora kugabanywamo ibyiciro bitatu: ethers ya selile, est est selile, na selile ether esther.Esters ya selulose ikoreshwa mubucuruzi ni: selitose nitrate, selile selile, selile ya acetate butyrate na selile xanthate.Ether ya selile irimo: methyl selulose, carboxymethyl selulose, Ethyl selulose, hydroxyethyl selulose, cyanoethyl selulose, hydroxypropyl selulose na hydroxypropyl methyl selulose.Mubyongeyeho, hari ester ether ivanze ikomoka.
Ibyiza nibikoreshwa Binyuze mu guhitamo insimburangingo ya reagent hamwe nuburyo bwo gutunganya ibintu, ibicuruzwa birashobora gushonga mumazi, kuvanga alkali igisubizo cyangwa ibishishwa kama, cyangwa bikagira imiti ya termoplastique, kandi birashobora gukoreshwa mugukora fibre chimique, firime, base ya firime, plastike, insulasiyo ibikoresho, ibifuniko, ibishishwa, gukwirakwiza polymeriki, inyongeramusaruro n'ibicuruzwa bya shimi bya buri munsi.Imiterere yibikomoka kuri selile bifitanye isano nimiterere yabasimbuye, impamyabumenyi ya DS yitsinda rya hydroxyl itatu kumatsinda ya glucose isimburwa, hamwe no gukwirakwiza insimburangingo kumurongo wa macromolecular.Bitewe nubushake bwa reaction, usibye ibicuruzwa byasimbuwe kimwe mugihe amatsinda atatu ya hydroxyl asimbuwe (DS ni 3), mubindi bihe (reaction ya homogeneous reaction cyangwa heterogeneous reaction), habonetse imyanya itatu itandukanye yo gusimbuza: Ibicuruzwa bivanze hamwe amatsinda ya glucosyl adasimbuwe: ① monosubstituted (DS ni 1, C, C cyangwa C imyanya isimbuwe, formulaire yuburyo reba selile);Imyanya idahwitse (DS ni 2, C, C, C, C Cyangwa C, C imyanya isimburwa);Gusimbuza byuzuye (DS ni 3).Kubwibyo, imiterere ya selile imwe ikomoka hamwe nigiciro kimwe cyo gusimbuza nayo irashobora kuba itandukanye cyane.Kurugero, diacetate ya selulose igereranywa na DS ya 2 ntishobora gushonga muri acetone, ariko diacetate ya selile yabonetse kubwo saponification ya triacetate ya selile yuzuye irashobora gushonga rwose muri acetone.Ubu butandukane bwo gusimburana bujyanye namategeko shingiro ya selulose ester na etherification reaction.
Amategeko shingiro ya selulose esterification na etherification reaction muri molekile ya selile, imyanya yitsinda rya hydroxyl itatu mumatsinda ya glucose iratandukanye, kandi ingaruka zinsimburangingo hamwe nimbogamizi zidasanzwe nazo ziratandukanye.Ugereranije acide hamwe nurwego rwo gutandukana mumatsinda atatu hydroxyl ni: C> C> C.Iyo reaction ya etherification ikozwe muburyo bwa alkaline, itsinda rya hydroxyl C ryitwara mbere, hanyuma C hydroxyl, hanyuma amaherezo ya C yibanze ya hydroxyl.Iyo reaction ya esterification ikozwe muburyo bwa acide, ingorane zo kwitwara kwa buri tsinda rya hydroxyl zinyuranye na gahunda ya etherification.Iyo witabiriye reagent yo gusimbuza cyane, ingaruka zo guhagarika steric zifite ingaruka zikomeye, kandi C hydroxyl groupe ifite ingaruka ntoya ya steric inzitizi byoroshye kubyitwaramo kuruta amatsinda ya hydroxyl ya C na C.
Cellulose ni polymer karemano.Ibyinshi muri esterification na etherification reaction ni reaction itandukanye iyo selile ikomeje gukomera.Ikwirakwizwa ryimiterere ya reaction igaruka muri fibre ya selile yitwa kugerwaho.Gahunda ya intermolecular yo mukarere ka kristaline itunganijwe neza, kandi reagent irashobora gukwirakwira gusa hejuru ya kristu.Gahunda ya intermolecular mukarere ka amorphous irekuye, kandi hariho andi matsinda ya hydroxyl yubusa byoroshye guhura na reagent, hamwe nuburyo bworoshye kandi bworoshye.Mubisanzwe, ibikoresho fatizo bifite kristu nini nubunini bwa kirisiti ntabwo byoroshye kubyitwaramo nkibikoresho fatizo bifite kristu ntoya hamwe nubunini bwa kristu.Ariko ibi ntabwo arukuri rwose, kurugero, igipimo cya acetylation ya fibre yumye ya viscose yumye hamwe na kristu yo hasi hamwe na kristu ntoya iri munsi cyane ugereranije na fibre ya pamba ifite kristu nini na kristu nini.Ni ukubera ko ingingo zimwe za hydrogène zihuza zitangwa hagati ya polymers yegeranye mugihe cyo kumisha, bikabuza ikwirakwizwa rya reagent.Niba ubuhehere buri mu bikoresho fatizo bya selulose bitose bisimbuzwa umusemburo munini (nka acide acetike, benzene, pyridine) hanyuma ukuma, reaction yacyo izatera imbere cyane, kuko gukama ntibishobora kwirukana burundu ibishishwa, na bimwe binini molekile zafatiwe mu “mwobo” w’ibikoresho fatizo bya selile, bikora ibyo bita selile.Intera yagutse no kubyimba ntabwo yoroshye gukira, ifasha ikwirakwizwa rya reagent, kandi iteza imbere igipimo cyibisubizo hamwe nuburinganire bwa reaction.Kubera iyo mpamvu, mubikorwa byo kubyara selile zitandukanye, hagomba kubaho kuvura kubyimba.Mubisanzwe amazi, aside cyangwa ubunini bwumuti wa alkali bikoreshwa nkibibyimba.Byongeye kandi, ingorane ziterwa na chimique yumuti ushonga hamwe nibipimo bimwe byumubiri na chimique akenshi usanga bitandukanye cyane, ibyo bikaba biterwa nimpamvu ziterwa na morphologique yubwoko butandukanye bwibimera cyangwa selile zifite imikorere ya biohimiki nuburyo butandukanye mubihingwa bimwe.Bya.Urukuta rwibanze rwurwego rwinyuma rwa fibre yibihingwa rutuma rwinjira muri reagent kandi rukarinda imiti y’imiti, bityo rero birakenewe ko hakoreshwa uburyo bujyanye na gahunda yo gusya kugirango dusenye urukuta rwibanze kugirango tubone ibishishwa bishonga hamwe nubushake bwiza.Kurugero, bagasse pulp ni ibikoresho bibisi bifite reaction nke mubikorwa bya viscose pulp.Mugihe utegura viscose (selulose xanthate alkali igisubizo), disulfide ikoreshwa cyane kuruta ipamba ya pamba na pome.Igipimo cyo kuyungurura kiri munsi ya viscose yateguwe hamwe nizindi pulps.Ni ukubera ko urukuta rwibanze rwa selile yibisheke rutigeze rwangirika neza mugihe cyo guterura no gutegura selile ya alkali selile muburyo busanzwe, bikaviramo ingorane mumyitwarire yumuhondo.
Imbere ya hydrolyzed alkaline bagasse pulp fibre] hamwe nishusho ya 2 ibyobo bisobanutse;mubihe byanyuma, nubwo ibyobo bizimira kubera kubyimba igisubizo cya alkali, urukuta rwibanze ruracyafite fibre yose.Niba "impregnation ya kabiri" (gusama bisanzwe bikurikirwa no gutera kabiri kwa kabiri hamwe nigisubizo cya alkali igisubizo hamwe ningaruka nini yo kubyimba) cyangwa gusya-gusya (gusama bisanzwe hamwe no gusya kwa mashini), reaction yumuhondo irashobora kugenda neza, igipimo cyo kuyungurura viscose ni Byateye imbere.Ni ukubera ko ubwo buryo bwombi bwavuzwe haruguru bushobora gukuramo urukuta rwibanze, bikagaragaza urwego rwimbere rwibintu byoroshye byoroshye, bikaba bifasha kwinjira muri reagent kandi bikanoza imikorere (reba ishusho ya 3 [kwinjiza kabiri kwa fibre ya bagasse pulp fibre) ], Igishushanyo cyo gusya Bagasse Pulp Fibre]).
Mu myaka ya vuba aha, sisitemu idafite amazi ashobora gushonga selile.Nka dimethylformamide na OYA, dimethyl sulfoxide na paraformaldehyde, hamwe nandi mashanyarazi avanze, nibindi, bituma selile ikora reaction imwe.Ariko, amwe mumategeko yavuzwe haruguru yimyitwarire itari mucyiciro ntagikurikizwa.Kurugero, mugihe utegura selile ya diacetate ya elegitoronike muri acetone, ntabwo ari ngombwa kunyura hydrolysis ya selile triacetate, ariko irashobora gutondekwa neza kugeza DS ifite 2.
Igihe cyo kohereza: Gashyantare-27-2023