A na-emepụta ihe ndị na-emepụta cellulose site na esterification ma ọ bụ etherification nke otu hydroxyl na cellulose polymers na reagents.Dabere na njirimara nhazi nke ngwaahịa mmeghachi omume, enwere ike kewaa ihe ndị na-emepụta cellulose n'ime ụzọ atọ: cellulose ethers, cellulose esters, na cellulose ether esters.Esters cellulose nke a na-eji eme ihe n'ezie bụ: cellulose nitrate, cellulose acetate, cellulose acetate butyrate na cellulose xanthate.Cellulose ethers gụnyere: methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, cyanoethyl cellulose, hydroxypropyl cellulose na hydroxypropyl methyl cellulose.Tụkwasị na nke ahụ, e nwere ester ether ngwakọta.
Njirimara na ojiji Site na nhọrọ nke nnọchi reagents na nhazi usoro, ngwaahịa nwere ike agbaze na mmiri, itughari alkali ngwọta ma ọ bụ organic mgbaze, ma ọ bụ nwere thermoplastic Njirimara, na ike ga-eji na-emepụta chemical eriri, ihe nkiri, film bases, plastics, insulating. ihe, mkpuchi, slurry, polymeric dispersant, nri mgbakwunye na ngwaahịa kemikal kwa ụbọchị.Njirimara nke ihe ndị na-emepụta cellulose na-ejikọta na ọdịdị nke ihe ndị na-anọchi anya ya, ogo DS nke otu hydroxyl atọ dị na otu glucose na-anọchi anya, na nkesa nke ihe ndị na-anọchi anya ya na agbụ macromolecular.N'ihi mmeghachi omume nke enweghị usoro, ewezuga ngwaahịa edochiri n'otu mgbe edochiri otu atọ hydroxyl (DS bụ 3), n'ọnọdụ ndị ọzọ (mmeghachi omume n'otu n'otu ma ọ bụ mmeghachi omume dị iche iche), a na-enweta ọnọdụ ngbanwe atọ dị iche iche: ngwaahịa agwakọta na Otu glucosyl ndị na-edochighị anya: ① monosubstituted (DS bụ 1, C, C ma ọ bụ C na-anọchi anya, usoro nhazi hụ cellulose);② gbanwere (DS bụ 2, C, C, C, C ma ọ bụ C, ọnọdụ C na-anọchi anya);③ nnọchi zuru oke (DS bụ 3).Ya mere, njirimara nke otu cellulose sitere na otu uru nnọchi nwere ike ịdị nnọọ iche.Dịka ọmụmaatụ, cellulose diacetate ozugbo esterified na DS nke 2 bụ ihe a na-adịghị ahụkebe na acetone, ma cellulose diacetate nwetara site na saponification nke cellulose triacetate zuru ezu nwere ike gbazee kpamkpam na acetone.Ọdịiche dị iche iche nke nnọchi a metụtara iwu ndị bụ isi nke cellulose ester na mmeghachi omume etherification.
Iwu bụ isi nke cellulose esterification na etherification mmeghachi omume na cellulose molekul, ọnọdụ nke atọ hydroxyl otu n'ime glucose otu dị iche iche, na mmetụta nke n'akụkụ n'akụkụ na steric mgbochi dịkwa iche iche.Acidity ikwu na ogo nke dissociation nke otu hydroxyl atọ bụ: C>C>C.Mgbe mmeghachi omume etherification na-eme na ọkara alkaline, otu C hydroxyl na-emeghachi omume mbụ, mgbe ahụ, otu C hydroxyl, na n'ikpeazụ, otu C primary hydroxyl.Mgbe mmeghachi omume esterification na-eme na usoro acidic, ihe isi ike nke mmeghachi omume nke otu hydroxyl ọ bụla na-emegide usoro mmeghachi omume etherification.Mgbe ị na-emeghachi omume na reagent buru ibu, mmetụta mgbochi siri ike nwere mmetụta dị mkpa, yana otu C hydroxyl nwere obere mmetụta mgbochi steetị dị mfe ime karịa otu C na C hydroxyl.
Cellulose bụ kristal eke polymer.Ọtụtụ n'ime mmeghachi omume esterification na etherification bụ mmeghachi omume dị iche iche mgbe cellulose nọgidere na-esi ike.Ọnọdụ mgbasa nke mmeghachi omume reagents n'ime eriri cellulose ka a na-akpọ iru eru.A na-ahazi nhazi intermolecular nke mpaghara kristal nke ọma, na reagent nwere ike gbasaa naanị n'elu kristal.Nhazi intermolecular na mpaghara amorphous na-atọ ụtọ, ma enwere ndị otu hydroxyl n'efu nke dị mfe ịkpọtụrụ ndị na-ahụ maka reagents, na-enwe ohere dị elu na mmeghachi omume dị mfe.N'ozuzu, akụrụngwa nwere nnukwu kristal na nnukwu kristal anaghị adị mfe ime dị ka akụrụngwa nwere obere kristal na obere kristal.Ma nke a abụghị eziokwu kpamkpam, dịka ọmụmaatụ, ọnụ ọgụgụ acetylation nke eriri viscose akọrọ na kristal dị ala na obere crystallinity dị ntakịrị karịa nke eriri owu nwere kristal dị elu na nnukwu crystallinity.Nke a bụ n'ihi na a na-emepụta ụfọdụ ihe njikọ hydrogen n'etiti polymers dị n'akụkụ n'oge usoro ihicha, nke na-egbochi mgbasa nke reagents.Ọ bụrụ na mmiri dị na cellulose raw material na-eji nnukwu ihe mgbaze organic (dị ka acetic acid, benzene, pyridine) dochie mmiri mmiri, mgbe ahụ, a ga-eme ka mmeghachi omume ya dịkwuo mma, n'ihi na ihicha enweghị ike ịchụpụ ihe mgbaze kpamkpam, na ụfọdụ buru ibu. A na-ejide ụmụ irighiri ihe n'ime "oghere" nke akụrụngwa cellulose, na-akpụ ihe a na-akpọ cellulose nwere.Ebe dị anya nke gbasaa site na ọzịza adịghị mfe iji nwetaghachi, nke na-eme ka mgbasa nke reagents, ma na-akwalite mmeghachi omume mmeghachi omume na ịdị n'otu nke mmeghachi omume.N'ihi nke a, n'ime usoro mmepụta nke cellulose dị iche iche, a ghaghị inwe ọgwụgwọ ọzịza kwekọrọ.A na-ejikarị mmiri, acid ma ọ bụ ụfọdụ ntinye nke ngwọta alkali eme ihe dị ka onye na-emepụta ọzịza.Tụkwasị na nke ahụ, ihe isi ike nke mmeghachi omume kemịkalụ nke mgbaze pulp nwere otu ihe ngosi anụ ahụ na nke kemịkalụ na-adịkarị iche, nke a na-akpata site na ihe morphological nke ụdị osisi dị iche iche ma ọ bụ sel nwere ọrụ biochemical na nhazi dị iche iche n'otu osisi.nke.The isi mgbidi nke elu oyi akwa nke osisi eriri egbochi penetration nke reagents na retards chemical Jeremaya mere, n'ihi ya, ọ na-adịkarị mkpa iji ọnọdụ kwekọrọ ekwekọ na pulping usoro ibibi isi mgbidi iji nweta dissolving pulp na mma reactivity.Ọmụmaatụ, bagasse pulp bụ akụrụngwa na-adịghị mma reactivity na mmepụta nke viscose pulp.Mgbe ị na-akwadebe viscose (cellulose xanthate alkali solution), a na-eri ọtụtụ carbon disulfide karịa owu linter pulp na osisi pulp.Ọnụego nzacha ahụ dị ala karịa nke viscose nke ejiri pulps ndị ọzọ kwadebere.Nke a bụ n'ihi na emebibeghị mgbidi bụ isi nke mkpụrụ ndụ okpete nke okpete nke ọma n'oge pulping na nkwadebe nke alkali cellulose site na usoro ọdịnala, na-ebute ihe isi ike na mmeghachi omume na-acha odo odo.
Pre-hydrolyzed alkaline bagasse pulp fibers] na Figure 2 [bagasse pulp fibers after alkali impregnation] bụ eletrọn microscope na-enyocha onyogho nke elu nke bagasse pulp fibers mgbe pre-hydrolyzed alkaline usoro na ot alkaline impregnation karị, nke mbụ ka nwere ike ịhụ ka olulu doro anya;na nke ikpeazụ, ọ bụ ezie na olulu na-apụ n'anya n'ihi ọzịza nke ngwọta alkali, mgbidi bụ isi ka na-ekpuchi eriri dum.Ọ bụrụ na "nke abụọ impregnation" (nkịtị impregnation sochiri nke abụọ impregnation na dilute alkali ngwọta na nnukwu ọzịza mmetụta) ma ọ bụ itinye-egweri (nkịtị impregnation jikọtara na n'ibu egweri) usoro, na yellowing mmeghachi omume nwere ike ịga n'ihu were were, na viscose filtration ọnụego. na-emeziwanye nke ọma.Nke a bụ n'ihi na ụzọ abụọ a dị n'elu nwere ike wepụ isi mgbidi ahụ, na-ekpughe oyi akwa dị n'ime nke mmeghachi omume dị mfe, nke na-eme ka ntinye nke reagents na-eme ka mmeghachi omume ahụ dịkwuo mma (Fig 3 [nke abụọ impregnation nke bagasse pulp fiber). ], Fig. Na-egweri Bagasse Pulp Fibers]).
N'ime afọ ndị na-adịbeghị anya, usoro ihe mgbaze na-abụghị mmiri nke nwere ike igbari cellulose ozugbo apụtala.Dị ka dimethylformamide na NO, dimethyl sulfoxide na paraformaldehyde, na ihe ndị ọzọ agwakọta ihe mgbaze, wdg, na-enyere cellulose aka ime a homogenous mmeghachi omume.Agbanyeghị, ụfọdụ iwu ndị a kpọtụrụ aha n'elu nke mmeghachi omume na-apụ apụ adịkwaghị emetụta.Dịka ọmụmaatụ, mgbe ị na-akwadebe cellulose diacetate soluble na acetone, ọ dịghị mkpa ka ị nweta hydrolysis nke cellulose triacetate, ma enwere ike ịme ya ozugbo ruo mgbe DS dị 2.
Oge nzipu: Feb-27-2023