Ukuguqulwa kwe-cellulose etherification

01. Ukuqaliswa kwe-cellulose

I-cellulose yi-macromolecular polysaccharide eyenziwe yiglucose. I-insoluble emanzini kunye nezinyibilikisi eziqhelekileyo eziphilayo. Yeyona nxalenye iphambili yodonga lweseli yesityalo, kwaye ikwayeyona isasazwe kakhulu kwaye ininzi i-polysaccharide kwindalo.

I-Cellulose sesona sixhobo sininzi esinokuphinda sihlaziyeke emhlabeni, kwaye ikwayipolymer yendalo enoqokelelo olukhulu. Ineengenelo zokuhlaziya, ukubola ngokupheleleyo, kunye nokuhambelana kwebhayoloji elungileyo.

02. Izizathu zokuguqula i-cellulose

I-cellulose macromolecules iqulethe inani elikhulu lamaqela -OH. Ngenxa yempembelelo yeebhondi zehydrogen, amandla phakathi kweemacromolecules mkhulu, nto leyo eya kukhokelela kwi-enthalpy enkulu yokunyibilika △H; kwelinye icala, kukho imisesane kwi cellulose macromolecules. Njengesakhiwo, ukuqina kwekhonkco le-molecular kukhulu, okuya kukhokelela kutshintsho oluncinci lwe-entropy entropy ΔS. Ezi zizathu zibini zenza ubushushu be-cellulose enyibilikisiweyo (= △H / △S ) buya kuba phezulu, kwaye iqondo lokushisa lokubola kweselulosi liphantsi. Ngoko ke, xa i-cellulose ifudumala kwiqondo lokushisa elithile, iifibers ziya kubonakala Isiganeko sokuba i-cellulose iye yachithwa ngaphambi kokuba iqale ukunyibilika, ngoko ke, ukuqhutyelwa kwezinto ze-cellulose akukwazi ukufumana indlela yokuqala yokunyibilika kunye nokubumba.

03. Ukubaluleka kokuguqulwa kwe-cellulose

Ngokuphela kancinci kwemithombo yefosili kunye neengxaki eziya zisanda zezendalo ezibangelwa yinkunkuma yamalaphu eekhemikhali zefayibha, uphuhliso nokusetyenziswa kwemathiriyeli yefiber ehlaziyekayo yendalo iye yaba yenye yeendawo ezishushu eziqwalaselwa ngabantu. I-Cellulose ngowona mthombo wendalo uhlaziyekayo kwindalo. Ineempawu ezigqwesileyo ezifana ne-hygroscopicity elungileyo, i-antistatic, i-air permeability eyomeleleyo, ukudaya okulungileyo, ukunxiba kakuhle, ukusetyenzwa lula kwelaphu, kunye nokubola kwezinto eziphilayo. Ineempawu ezingenakuthelekiswa neentambo zekhemikhali. .

Iimolekyuli ze-cellulose ziqulethe inani elikhulu lamaqela e-hydroxyl, ekulula ukwenza i-intramolecular kunye ne-intermolecular hydrogen bond, kwaye ibole kumaqondo aphezulu ngaphandle kokunyibilika. Nangona kunjalo, i-cellulose ine-reactivity enhle, kwaye ibhondi yayo ye-hydrogen inokutshatyalaliswa ngokuguqulwa kweekhemikhali okanye ukuxutywa kwe-grafting, enokunciphisa ngokufanelekileyo indawo yokunyibilika. Njengeemveliso ezahlukeneyo zemizi-mveliso, isetyenziswa kakhulu kwilaphu, ukwahlula inwebu, iiplastiki, icuba kunye neengubo.

04. Ukuguqulwa kwe-cellulose etherification

I-ether ye-cellulose luhlobo lwe-cellulose derivative efunyenwe ngokuguqulwa kwe-etherification ye-cellulose. Isetyenziswa ngokubanzi ngenxa yokuqina kwayo okugqwesileyo, i-emulsification, ukumiswa, ukubunjwa kwefilimu, i-colloid ekhuselayo, ukugcinwa komswakama, kunye neempawu zokubambelela. Isetyenziselwa ukutya, amayeza, ukwenza iphepha, ipeyinti, izinto zokwakha, njl.

I-Etherification ye-cellulose luhlu lwee-derivatives eziveliswa yi-reaction yamaqela e-hydroxyl kwi-cellulose ye-molecular chain kunye ne-alkylating agents phantsi kweemeko ze-alkaline. Ukusetyenziswa kwamaqela e-hydroxyl kunciphisa inani le-intermolecular hydrogen bonds ukunciphisa amandla e-intermolecular, ngaloo ndlela Ukuphucula ukuzinza kwe-thermal ye-cellulose, ukuphucula ukusebenza kokusebenza kwezinto, kwaye kwangaxeshanye ukunciphisa i-melting point of cellulose.

Imizekelo yeziphumo zokuguqulwa kwe-etherification kweminye imisebenzi ye-cellulose:

Ukusebenzisa ikotoni esulungekileyo njengesiseko sezinto ezisisiseko, abaphandi basebenzise inkqubo ye-etherification yenyathelo elinye ukulungiselela i-carboxymethyl hydroxypropyl cellulose ether eyinkimbinkimbi kunye ne-react reaction, i-viscosity ephezulu, ukuxhathisa okulungileyo kwe-asidi kunye nokuxhathisa ityuwa ngokusebenzisa i-alkalization kunye ne-etherification reactions. Isebenzisa inkqubo ye-etherification enenyathelo elinye, i-carboxymethyl hydroxypropyl cellulose eveliswayo inokumelana netyuwa elungileyo, ukuxhathisa kweasidi kunye nokunyibilika. Ngokutshintsha izixa ezihambelanayo zepropylene oxide kunye ne-chloroacetic acid, iimveliso ezine-carboxymethyl ezahlukeneyo kunye neziqulatho ze-hydroxypropyl zinokulungiswa. Iziphumo zovavanyo zibonisa ukuba i-carboxymethyl hydroxypropyl cellulose eveliswe yindlela enenyathelo elinye inomjikelezo omfutshane wokuvelisa, ukusetyenziswa kwe-solvent ephantsi, kwaye imveliso inokumelana okugqwesileyo kwi-monovalent kunye ne-divalent salts kunye nokuchasana okuhle kwe-asidi.

05. Ithemba lokuguqulwa kwe-cellulose etherification

I-Cellulose yinto ebalulekileyo yeekhemikhali kunye neekhemikhali zezinto eziluhlaza ezityebileyo kwizibonelelo, eziluhlaza kunye nokusingqongileyo, kunye nokuhlaziywa. Izinto eziphuma kwi-cellulose etherification modification zinentsebenzo egqwesileyo, uluhlu olubanzi losetyenziso kunye neziphumo ezigqwesileyo zokusetyenziswa, kwaye zihlangabezana neemfuno zoqoqosho lwesizwe kakhulu. Kwaye iimfuno zophuhliso lwentlalo, kunye nenkqubela phambili yetekhnoloji kunye nokufezekiswa korhwebo kwixa elizayo, ukuba izinto zokwenziwa ekrwada kunye neendlela zokwenziwa kwe-cellulose derivatives zinokuba nemveliso ngakumbi, ziya kusetyenziswa ngokupheleleyo kwaye ziqonde uluhlu olubanzi lwezicelo. . Ixabiso