Ci gaban Bincike Kan Polyurethanes Marasa Isocyanate
Tun lokacin da aka fara amfani da su a shekarar 1937, kayan polyurethane (PU) sun sami aikace-aikace masu yawa a fannoni daban-daban, ciki har da sufuri, gini, sinadarai masu amfani da man fetur, yadi, injiniyan injiniya da lantarki, sararin samaniya, kiwon lafiya, da noma. Ana amfani da waɗannan kayan a cikin nau'ikan kamar filastik kumfa, zare, elastomers, masu hana ruwa shiga, fata ta roba, shafa, manne, kayan shimfidawa da kayan likita. PU na gargajiya galibi ana haɗa shi ne daga isocyanates biyu ko fiye tare da polyols na macromolecular da ƙananan masu faɗaɗa sarkar kwayoyin halitta. Duk da haka, gubar da ke tattare da isocyanates tana haifar da haɗari mai yawa ga lafiyar ɗan adam da muhalli; ƙari ga haka, galibi ana samun su ne daga phosgene - wani abu mai guba sosai - da kuma kayan amine masu dacewa.
Dangane da yadda masana'antar sinadarai ta zamani ke bin diddigin ayyukan ci gaba masu dorewa da kore, masu bincike suna ƙara mai da hankali kan maye gurbin isocyanates da albarkatun da ba su da illa ga muhalli yayin da suke bincika sabbin hanyoyin haɗa sinadarai don polyurethanes marasa isocyanate (NIPU). Wannan takarda ta gabatar da hanyoyin shiryawa don NIPU yayin da take duba ci gaba a nau'ikan NIPU daban-daban da kuma tattauna makomarsu ta gaba don samar da ma'ana don ƙarin bincike.
1 Haɗakar Polyurethanes marasa Isocyanate
Haɗakar farko ta mahaɗan carbamate masu ƙarancin nauyin ƙwayoyin halitta ta amfani da monocyclic carbonates tare da aliphatic diamines ta faru a ƙasashen waje a cikin shekarun 1950 - wanda ke nuna muhimmin lokaci ga haɗakar polyurethane mara isocyanate. A halin yanzu akwai manyan hanyoyi guda biyu don samar da NIPU: Na farko ya ƙunshi halayen ƙari na mataki-mataki tsakanin binary cyclic carbonates da binary amines; na biyu ya ƙunshi halayen polycondensation wanda ya haɗa da tsaka-tsakin diurethane tare da diols waɗanda ke sauƙaƙe musayar tsari a cikin carbamates. Ana iya samun tsaka-tsakin diarboxylate ta hanyar ko dai hanyoyin cyclic carbonate ko dimethyl carbonate (DMC); ainihin dukkan hanyoyin suna amsawa ta hanyar ƙungiyoyin carbonic acid waɗanda ke samar da ayyukan carbamate.
Sassan da ke ƙasa suna bayani dalla-dalla kan hanyoyi guda uku daban-daban na haɗa polyurethane ba tare da amfani da isocyanate ba.
1.1 Hanyar Binary Cyclic Carbonate
Ana iya haɗa NIPU ta hanyar ƙarawa mataki-mataki wanda ya haɗa da binary cyclic carbonate tare da binary amine kamar yadda aka nuna a Hoto na 1.
Saboda ƙungiyoyin hydroxyl da yawa da ke cikin raka'o'in da ke maimaitawa tare da babban tsarin sarkar sa, wannan hanyar gabaɗaya tana samar da abin da ake kira polyβ-hydroxyl polyurethane (PHU). Leitsch et al., sun ƙirƙiro jerin PHUs na polyether waɗanda ke amfani da polyethers masu ƙarewa na carbonate tare da amines binary da ƙananan ƙwayoyin halitta da aka samo daga binary cyclic carbonates - suna kwatanta waɗannan da hanyoyin gargajiya da ake amfani da su don shirya polyether PUs. Bincikensu ya nuna cewa ƙungiyoyin hydroxyl a cikin PHUs suna samar da haɗin hydrogen cikin sauƙi tare da atom ɗin nitrogen/oxygen waɗanda ke cikin sassa masu laushi/tauri; bambance-bambance tsakanin sassa masu laushi kuma suna tasiri ga halayen haɗin hydrogen da kuma digirin rabuwa na microphase wanda daga baya ke shafar halayen aiki gaba ɗaya.
Yawanci ana yin wannan hanyar a ƙasa da zafin jiki da ya wuce digiri 100 na Celsius, wanda hakan ke haifar da rashin jin daɗi ga danshi, yayin da yake samar da samfuran da ba su da matsala wajen canzawa, amma yana buƙatar sinadarai masu narkewa waɗanda ke da alaƙa da ƙarfi kamar dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), da sauransu. Bugu da ƙari, tsawaita lokutan amsawa tsakanin kwana ɗaya zuwa kwana biyar galibi suna haifar da ƙarancin nauyin kwayoyin halitta, wanda ke raguwa a ƙasa da iyaka kusan 30kg/mol, wanda ke haifar da babban samarwa mai ƙalubale saboda babban farashin da ke tattare da shi, tare da ƙarancin ƙarfi da aka nuna ta hanyar PHUs masu zuwa duk da cewa aikace-aikacen da aka yi alƙawarin yi sun haɗa da sassan kayan da ke danshi, ƙirar ƙwaƙwalwar ajiya, hanyoyin manne, kumfa da sauransu.
1.2 Hanyar Monocylic Carbonate
Monocylic carbonate yana amsawa kai tsaye tare da dicarbamate wanda ya samo asali daga diamine wanda ke da ƙungiyoyin ƙarshen hydroxyl waɗanda daga nan suka shiga hulɗa ta musamman ta transesterification/polycondensation tare da diols daga ƙarshe suna samar da NIPU mai kama da na gargajiya wanda aka nuna a gani ta hanyar Hoto na 2.
Bambance-bambancen monocylic da aka saba amfani da su sun haɗa da ethylene & propylene carbonated substrates inda ƙungiyar Zhao Jingbo a Jami'ar Fasaha ta Sinadarai ta Beijing ta yi amfani da diamines daban-daban don mayar da martani ga waɗannan halittu masu zagaye, inda suka fara samun nau'ikan masu shiga tsakani na tsarin dicarbamate daban-daban kafin su ci gaba zuwa matakan daskarewa ta amfani da ko dai polytetrahydrofuranediol/polyether-diols, wanda ya haifar da nasarar samuwar layukan samfura daban-daban, waɗanda ke nuna kyawawan halaye na zafi/injini waɗanda suka kai sama da maki na narkewa suna shawagi a kusa da kewayon da ke tsakanin kusan 125 ~ 161°C ƙarfin tururin iska, wanda ke kusa da 24MPa, ƙimar tsawaitawa kusan 1476%. Wang da abokan aikinsa, irin waɗannan haɗuwa da aka yi amfani da su waɗanda suka haɗa da DMC an haɗa su bi da bi tare da hexamethylenediamine/cyclocarbonated precursors waɗanda ke haɗa abubuwan da aka samo daga hydroxy-endated derivatives daga baya waɗanda aka yi amfani da su azaman dibasic acid na halitta kamar oxalic/sebacic/acids adipic-acid-terephthalics waɗanda suka cimma sakamako na ƙarshe waɗanda ke nuna kewayon da ya ƙunshi ƙarfin tensile 13k ~ 28k g/mol yana canzawa 9 ~ 17 MPa elongations bambanta 35% ~ 235%.
Cyclocarbonic esters suna aiki yadda ya kamata ba tare da buƙatar masu kara kuzari a ƙarƙashin yanayi na yau da kullun ba, suna kiyaye yanayin zafi kusan 80° zuwa 120°C, bayan haka, transesterifications yawanci suna amfani da tsarin catalytic na tushen organotin don tabbatar da ingantaccen aiki ba ya wuce 200°. Bayan ƙoƙarin danshi kawai, wanda ke niyya ga shigarwar diolic, abubuwan da ke haifar da haɓakar kai-tsaye/deglycolysis, wanda ke sauƙaƙe samar da sakamakon da ake so, yana sa hanyar ta zama mai dacewa ga muhalli, wanda galibi ke samar da ragowar methanol/ƙananan ƙwayoyin halitta-diolic, don haka yana gabatar da madadin masana'antu masu inganci a nan gaba.
Hanyar Dimethyl Carbonate ta 1.3
DMC tana wakiltar madadin da ke da lafiya/mara guba ga muhalli wanda ke nuna sassa daban-daban na aiki, ciki har da tsarin methyl/methoxy/carbonyl, wanda ke haɓaka bayanan amsawa, wanda ke ba da damar yin hulɗa ta farko, wanda hakan ke ba da damar yin hulɗa kai tsaye tare da diamines, waɗanda ke samar da ƙananan masu shiga tsakani na methyl-carbamate, waɗanda aka dakatar daga aiki, sannan kuma ayyukan narkewar narkewa, waɗanda suka haɗa da ƙarin ƙananan abubuwan da ke ɗauke da sarkar-extender-diolics/manyan polyol, waɗanda ke haifar da fitowar tsarin polymer da aka nuna ta hanyar Hoto na 3.
Deepa et.al sun yi amfani da ƙarfin da aka ambata a baya wajen yin amfani da sinadarin sodium methoxide wajen tsara nau'ikan tsaka-tsaki daban-daban, daga baya suka shiga cikin faɗaɗa da aka yi niyya, wanda ya kai ga jerin abubuwan da suka kai ga nauyin kwayoyin halitta kimanin (3 ~20) x10^3g/mol yanayin zafi na canjin gilashin da ya ratsa (-30 ~120°C). Pan Dongdong ya zaɓi haɗin gwiwa na dabaru waɗanda suka haɗa da DMC hexamethylene-diaminopolycarbonate-polyalcohols, waɗanda suka gano sakamako masu kyau waɗanda ke nuna ma'aunin ƙarfi na tensile-strength oscillating 10-15MPa elongation ratio kusa da 1000%-1400%. Binciken da aka gudanar game da tasirin sarka daban-daban ya nuna fifikon da ya dace wajen daidaita zaɓin butanediol/hexanediol lokacin da daidaiton adadin atomic ya ci gaba da daidaita daidaiton haɓaka lu'ulu'u da aka tsara a cikin sarka. Ƙungiyar Sarazin ta shirya abubuwan haɗin gwiwa waɗanda suka haɗa lignin/DMC tare da hexahydroxyamine waɗanda ke nuna halayen injiniya masu gamsarwa bayan sarrafawa a 230℃. Ƙarin bincike da aka yi niyya don samar da waɗanda ba isocyante-polyureas ba ta amfani da haɗin diazomonomer ana tsammanin aikace-aikacen fenti masu yuwuwa suna fitowa da fa'idodi masu kwatantawa akan takwarorinsu na vinyl-carbonaceous waɗanda ke nuna ingancin farashi/faɗin hanyoyin samowa. Yin bincike mai kyau game da hanyoyin da aka haɗa da yawa yawanci yana buƙatar yanayin zafi mai yawa/vacuum wanda ke hana buƙatun narkewar abinci ta haka rage kwararar sharar da aka iyakance kawai ga methanol/ƙananan ƙwayoyin halitta-diolic waɗanda ke kafa tsarin haɗin kore gabaɗaya.
Sassan laushi guda biyu daban-daban na polyurethane marasa isocyanate
2.1 Polyether polyurethane
Ana amfani da polyurethane polyether (PEU) sosai saboda ƙarancin ƙarfin haɗin kai na haɗin ether a cikin raka'o'in maimaita sassa masu laushi, sauƙin juyawa, kyakkyawan sassaucin yanayin zafi da juriya ga hydrolysis.
Kebir da abokan aikinsa sun haɗa polyether polyurethane tare da DMC, polyethylene glycol da butanediol a matsayin kayan masarufi, amma nauyin kwayoyin halitta bai yi ƙasa ba (7 500 ~ 14 800g/mol), Tg ya yi ƙasa da 0℃, kuma wurin narkewar shi ma ya yi ƙasa (38 ~ 48℃), kuma ƙarfi da sauran alamu sun yi wahalar biyan buƙatun amfani. Ƙungiyar bincike ta Zhao Jingbo ta yi amfani da ethylene carbonate, 1, 6-hexanediamine da polyethylene glycol don haɗa PEU, wanda ke da nauyin kwayoyin halitta na 31 000g/mol, ƙarfin juriya na 5 ~ 24MPa, da kuma tsawaitawa a lokacin karyewar 0.9% ~ 1 388%. Nauyin kwayoyin halitta na jerin sinadaran aromatic polyurethanes da aka haɗa shine 17 300 ~ 21 000g/mol, Tg shine -19 ~ 10℃, wurin narkewa shine 102 ~ 110℃, ƙarfin tensile shine 12 ~ 38MPa, kuma saurin dawo da roba na tsawon 200% akai-akai shine 69% ~ 89%.
Ƙungiyar bincike ta Zheng Liuchun da Li Chuncheng sun shirya matsakaicin 1, 6-hexamethylenediamine (BHC) tare da dimethyl carbonate da 1, 6-hexamethylenediamine, da kuma polycondensation tare da ƙananan ƙwayoyin halitta daban-daban madaidaiciya sarkar diols da polytetrahydrofuranediols (Mn=2 000). An shirya jerin polyether polyurethanes (NIPEU) tare da hanyar da ba ta isocyanate ba, kuma an warware matsalar haɗin gwiwa na tsaka-tsaki yayin amsawar. An kwatanta tsari da kaddarorin polyether polyurethane (HDIPU) na gargajiya da NIPEU da 1, 6-hexamethylene diisocyanate suka shirya, kamar yadda aka nuna a cikin Jadawali na 1.
| Samfuri | Jakar taro mai tauri/% | Nauyin kwayoyin halitta/(g)·mol^(-1)) | Ma'aunin rarraba nauyin kwayoyin halitta | Ƙarfin tauri/MPa | Tsawaitawa a lokacin hutu/% |
| NIPEU30 | 30 | 74000 | 1.9 | 12.5 | 1250 |
| NIPEU40 | 40 | 66000 | 2.2 | 8.0 | 550 |
| HDIPU30 | 30 | 46000 | 1.9 | 31.3 | 1440 |
| HDIPU40 | 40 | 54000 | 2.0 | 25.8 | 1360 |
Tebur 1
Sakamakon da aka samu a Jadawali na 1 ya nuna cewa bambance-bambancen tsari tsakanin NIPEU da HDIPU galibi sun faru ne saboda ɓangaren tauri. Ƙungiyar urea da aka samar ta hanyar amsawar gefe na NIPEU an saka ta bazuwar a cikin sarkar kwayoyin halitta mai tauri, yana karya ɓangaren tauri don samar da haɗin hydrogen da aka tsara, wanda ke haifar da raunin haɗin hydrogen tsakanin sarkar kwayoyin halitta na ɓangaren tauri da ƙarancin lu'ulu'u na ɓangaren tauri, wanda ke haifar da rabuwar NIPEU mai ƙarancin lokaci. Sakamakon haka, halayen injiniyansa sun fi HDIPU muni.
2.2 Polyester Polyurethane
Polyurethane polyester (PETU) tare da polyester diols a matsayin sassa masu laushi yana da kyawawan lalacewa ta halitta, jituwa ta halitta da kuma kaddarorin injiniya, kuma ana iya amfani da shi don shirya kayan aikin injiniya na nama, wanda kayan aikin likitanci ne mai kyawawan damar amfani. Polyester diols da aka saba amfani da su a cikin sassa masu laushi sune polybutylene adipate diol, polyglycol adipate diol da polycaprolactone diol.
Tun da farko, Rokicki da abokan aikinsa sun yi amfani da ethylene carbonate tare da diamine da diols daban-daban (1, 6-hexanediol,1, 10-n-dodecanol) don samun NIPU daban-daban, amma NIPU da aka haɗa tana da ƙarancin nauyin kwayoyin halitta da ƙananan Tg. Farhadian da abokan aikinsa sun shirya polycyclic carbonate ta amfani da man sunflower iri a matsayin kayan da aka samar, sannan suka haɗa da bio-based polyamines, an shafa a kan faranti, sannan aka warke a 90 ℃ na tsawon awanni 24 don samun thermosetting polyester polyurethane film, wanda ya nuna kyakkyawan kwanciyar hankali na zafi. Ƙungiyar bincike ta Zhang Liqun daga Jami'ar Fasaha ta Kudancin China ta haɗa jerin diamines da cyclic carbonates, sannan aka haɗa su da biobased dibasic acid don samun biobased polyester polyurethane polyurethane. Ƙungiyar bincike ta Zhu Jin a Cibiyar Bincike ta Kayan Aiki ta Ningbo, Kwalejin Kimiyya ta Sin ta shirya ɓangaren diaminodiol mai tauri ta amfani da hexadiamine da vinyl carbonate, sannan aka haɗa polycondensation tare da bio-based unsaturated dibasic acid don samun jerin polyester polyurethane, wanda za'a iya amfani da shi azaman fenti bayan warkar da ultraviolet [23]. Ƙungiyar bincike ta Zheng Liuchun da Li Chuncheng sun yi amfani da adipic acid da kuma aliphatic diols guda huɗu (butanediol, hexadiol, octenediol da decanediol) tare da lambobin atom na carbon daban-daban don shirya polyester diols masu dacewa a matsayin sassa masu laushi; An samo ƙungiyar polyurethane polyester polyester marasa isocyanate (PETU), wacce aka sanya wa suna bayan adadin atom na carbon na aliphatic diols, ta hanyar narkar da polycondensation tare da prepolymer mai tauri na hydroxy-sealed hydroxy wanda BHC da diols suka shirya. An nuna halayen injiniya na PETU a cikin Jadawali na 2.
| Samfuri | Ƙarfin tauri/MPa | Modulus mai laushi/MPa | Tsawaitawa a lokacin hutu/% |
| PETU4 | 6.9±1.0 | 36±8 | 673±35 |
| PETU6 | 10.1±1.0 | 55±4 | 568±32 |
| PETU8 | 9.0±0.8 | 47±4 | 551±25 |
| PETU10 | 8.8±0.1 | 52±5 | 137±23 |
Tebur na 2
Sakamakon ya nuna cewa ɓangaren laushi na PETU4 yana da mafi girman yawan carbonyl, mafi ƙarfi haɗin hydrogen tare da ɓangaren tauri, da kuma mafi ƙarancin matakin rabuwar matakai. Ƙirgawar sassan laushi da tauri tana da iyaka, tana nuna ƙarancin wurin narkewa da ƙarfin tensile, amma mafi girman tsayi a lokacin karyewa.
2.3 Polycarbonate polyurethane
Polycarbonate polycarbonate (PCU), musamman aliphatic PCU, yana da kyakkyawan juriya ga hydrolysis, juriya ga iskar shaka, kyakkyawan kwanciyar hankali na halittu da kuma jituwa ta halitta, kuma yana da kyakkyawan damar amfani a fannin maganin halittu. A halin yanzu, yawancin NIPU da aka shirya suna amfani da polyether polyols da polyester polyols a matsayin sassa masu laushi, kuma akwai rahotannin bincike kaɗan kan polycarbonate polycarbonate.
Polyurethane polycarbonate mara isocyanate da ƙungiyar bincike ta Tian Hengshui ta Jami'ar Fasaha ta Kudancin China ta shirya yana da nauyin kwayoyin halitta sama da 50,000 g/mol. An yi nazarin tasirin yanayin amsawa akan nauyin kwayoyin halittar polymer, amma ba a bayar da rahoton halayen injiniyansa ba. Ƙungiyar bincike ta Zheng Liuchun da Li Chuncheng sun shirya PCU ta amfani da DMC, hexanediamine, hexadiol da polycarbonate diols, kuma sun sanya wa PCU suna bisa ga ƙashin taro na sashin maimaituwa mai tauri. An nuna halayen injiniya a cikin Jadawali na 3.
| Samfuri | Ƙarfin tauri/MPa | Modulus mai laushi/MPa | Tsawaitawa a lokacin hutu/% |
| PCU18 | 17±1 | 36±8 | 665±24 |
| PCU33 | 19±1 | 107±9 | 656±33 |
| PCU46 | 21±1 | 150±16 | 407±23 |
| PCU57 | 22±2 | 210±17 | 262±27 |
| PCU67 | 27±2 | 400±13 | 63±5 |
| PCU82 | 29±1 | 518±34 | 26±5 |
Tebur na 3
Sakamakon ya nuna cewa PCU tana da nauyin kwayoyin halitta mai yawa, har zuwa 6×104 ~ 9×104g/mol, wurin narkewa har zuwa 137 ℃, da kuma ƙarfin tensile har zuwa 29 MPa. Ana iya amfani da irin wannan PCU ko dai a matsayin filastik mai tauri ko kuma a matsayin elastomer, wanda ke da kyakkyawan damar amfani a fannin ilimin halittu (kamar su kayan aikin injiniyan nama na ɗan adam ko kayan dasa zuciya da jijiyoyin jini).
2.4 Polyurethane mara isocyanate mai hade
Polyurethane mai haɗakarwa wanda ba ya isocyanate ba (NIPU mai haɗakarwa) shine gabatar da ƙungiyar epoxy resin, acrylate, silica ko siloxane a cikin tsarin ƙwayoyin polyurethane don samar da hanyar sadarwa mai shiga tsakani, inganta aikin polyurethane ko ba wa polyurethane ayyuka daban-daban.
Feng Yuelan da abokan aikinsa sun mayar da martani ga man waken soya na epoxy mai tushen bio-based tare da CO2 don haɗa pentamonical cyclic carbonate (CSBO), kuma sun gabatar da bisphenol A diglycidyl ether (epoxy resin E51) tare da ƙarin sassan sarka masu tauri don ƙara inganta NIPU da CSBO ya samar wanda aka ƙarfafa da amine. Sarkar kwayoyin halitta ta ƙunshi dogon sashin sarka mai sassauƙa na oleic acid/linoleic acid. Hakanan ya ƙunshi ƙarin sassan sarka masu tauri, don haka yana da ƙarfi mai ƙarfi da ƙarfi mai yawa. Wasu masu bincike sun kuma haɗa nau'ikan prepolymers na NIPU guda uku tare da ƙungiyoyin ƙarshen furan ta hanyar amsawar buɗewa ta sauri na diethylene glycol bicyclic carbonate da diamine, sannan suka yi aiki da polyester mara cika don shirya polyurethane mai laushi tare da aikin warkar da kai, kuma sun sami nasarar gano ingantaccen aikin warkar da kai na NIPU mai laushi. NIPU mai haɗaka ba wai kawai yana da halayen NIPU gabaɗaya ba, har ma yana iya samun mafi kyawun mannewa, juriyar lalata acid da alkali, juriyar narkewa da ƙarfin injiniya.
3 Hasashen
Ana shirya NIPU ba tare da amfani da isocyanate mai guba ba, kuma a halin yanzu ana nazarinsa a cikin nau'in kumfa, shafi, manne, elastomer da sauran kayayyaki, kuma yana da fa'idodi da yawa na amfani. Duk da haka, yawancinsu har yanzu suna iyakance ga binciken dakin gwaje-gwaje, kuma babu wani babban samarwa. Bugu da ƙari, tare da inganta yanayin rayuwar mutane da ci gaba da ƙaruwar buƙata, NIPU mai aiki ɗaya ko ayyuka da yawa ya zama muhimmin alkiblar bincike, kamar maganin kashe ƙwayoyin cuta, gyaran kai, ƙwaƙwalwar siffa, hana harshen wuta, juriyar zafi mai yawa da sauransu. Saboda haka, binciken nan gaba ya kamata ya fahimci yadda za a shawo kan manyan matsalolin masana'antu kuma a ci gaba da bincika alkiblar shirya NIPU mai aiki.
Lokacin Saƙo: Agusta-29-2024