Ibyo bitapolyurethaneni impfunyapfunyo ya polyurethane, ikorwa nigikorwa cya polyisocyanates na polyol, kandi ikubiyemo amatsinda menshi asubiramo amine ester (- NH-CO-O -) kumurongo wa molekile.Mubisumizi nyabyo bya polyurethane bisigara, usibye itsinda rya amino ester, hariho kandi amatsinda nka urea na biuret.Polyol ni iy'iminyururu miremire ifite amatsinda ya hydroxyl ku musozo, ibyo bita "urunigi rworoshye", naho polyisocyanates yitwa "ibice bikomeye".
Mubisigarira bya polyurethane byakozwe nibice byoroshye kandi bikomeye, ijanisha rito ni est est aside amine, kubwibyo ntibikwiye ko tubita polyurethane.Muburyo bwagutse, polyurethane ninyongera ya isocyanate.
Ubwoko butandukanye bwa isocyanates bifata hamwe na polyhydroxy kugirango bibyare ibintu bitandukanye bya polyurethane, bityo ubone ibikoresho bya polymer bifite imitungo itandukanye, nka plastiki, reberi, ibifuniko, fibre, ibifunga, nibindi.
Ibikoresho bya polyurethane ni ubwoko bwihariye bwa reberi, bikozwe mugukora polyether cyangwa polyester hamwe na isocyanate.Hariho ubwoko bwinshi bitewe nubwoko butandukanye bwibikoresho fatizo, imiterere yimikorere, nuburyo bwo guhuza.Uhereye ku miterere yimiti, hariho ubwoko bwa polyester na polyether, kandi duhereye kuburyo bwo gutunganya, hari ubwoko butatu: kuvanga ubwoko, ubwoko bwa casting, nubwoko bwa thermoplastique.
Rubber ya syntetique polyurethane isanzwe ikomatanyirizwa mugukora polyester yumurongo cyangwa polyether hamwe na diisocyanate kugirango habeho uburemere buke bwa prepolymer, hanyuma bigakorerwa kwaguka kumurongo kugirango habeho polimeri iremereye cyane.Noneho, ibikoresho bikwiye byo guhuza byongeweho kandi bishyushye kugirango bikire, bihinduke reberi yibirunga.Ubu buryo bwitwa prepolymerisation cyangwa inzira ebyiri.
Birashoboka kandi gukoresha uburyo bwintambwe imwe - kuvanga umurongo wa polyester cyangwa polyether hamwe na diisocyanates, kwagura urunigi, hamwe no guhuza imiyoboro kugirango utangire reaction kandi ubyare reberi ya polyurethane.
A-agace muri molekile ya TPU ituma iminyururu ya macromolecular yoroha kuzunguruka, igaha reberi ya polyurethane hamwe na elastique nziza, kugabanya aho koroshya hamwe ninzibacyuho ya kabiri ya polymer, no kugabanya ubukana bwimbaraga nimbaraga za mashini.B-igice kizahuza kuzenguruka iminyururu ya macromolekulaire, itume ingingo yoroshye hamwe ninzibacyuho ya kabiri ya polymer yiyongera, bikavamo kwiyongera gukomera nimbaraga za mashini, no kugabanuka kwa elastique.Muguhindura igipimo cya mara hagati ya A na B, TPU ifite imiterere itandukanye irashobora kubyara.Imiterere ihuza imiterere ya TPU ntigomba gutekereza gusa guhuza ibice byambere, ahubwo igomba no guhuza ibice byombi byatewe na hydrogen ihuza molekile.Ihuriro ryibanze ryihuza polyurethane ritandukanye nuburyo bwa volcanisation ya rubber ya hydroxyl.Itsinda ryayo rya amino ester, itsinda rya biuret, urea ikora itsinda hamwe nandi matsinda akora atunganijwe mugice gisanzwe kandi gitandukanijwe cyumunyururu, bikavamo imiterere isanzwe y'urusobekerane rwa reberi, ifite imbaraga zo kwihanganira kwambara nibindi byiza byiza.Icya kabiri, bitewe nuko hariho amatsinda menshi akora cyane nka urea cyangwa karbamate mumashanyarazi ya polyurethane, imigozi ya hydrogène ikorwa hagati yiminyururu ya molekile ifite imbaraga nyinshi, kandi isano ya kabiri ihuza ibice byakozwe na hydrogène nayo igira ingaruka zikomeye kumiterere ya rubber.Secondary cross-ihuza ituma reberi ya polyurethane kugira ibiranga elastomers ya thermosetting kuruhande rumwe, kurundi ruhande, uku guhuza ntiguhuza rwose, bigatuma bihuza rwose.Imiterere-ihuza imiterere biterwa nubushyuhe.Mugihe ubushyuhe bwiyongereye, uku guhuza buhoro buhoro gucika intege.Polimeri ifite amazi menshi kandi irashobora gukorerwa thermoplastique.Iyo ubushyuhe bugabanutse, uku guhuza guhuza gukira buhoro buhoro.Kwiyongera kwinshi kwuzuza byongera intera iri hagati ya molekile, bigabanya ubushobozi bwo gukora hydrogène ihuza molekile, kandi biganisha ku kugabanuka gukabije kwimbaraga.Ubushakashatsi bwerekanye ko gahunda yo gutuza mumatsinda atandukanye akora muri reberi ya polyurethane kuva hejuru kugeza hasi ni: ester, ether, urea, karbamate, na biuret.Mugihe cyo gusaza kwa reberi ya polyurethane, intambwe yambere nukuvunika guhuza imiyoboro ihuza biuret na urea, hagakurikiraho kumena karbamate na urea, ni ukuvuga kumena urunigi nyamukuru.
01 Kworoshya
Polyurethane elastomers, nkibikoresho byinshi bya polymer, byoroha mubushyuhe bwinshi no kuva mumiterere ya elastike ikajya mumiterere yimitsi, bigatuma imbaraga za mashini zigabanuka vuba.Urebye imiti, ubushyuhe bworoheje bwa elastique buterwa ahanini nibintu nkibigize imiti, uburemere bwa molekile, hamwe nubucucike.
Muri rusange, kongera uburemere bwa molekile ugereranije, kongera ubukana bwigice gikomeye (nko kwinjiza impeta ya benzene muri molekile) hamwe nibiri mu gice gikomeye, no kongera ubucucike bwambukiranya byose ni ingirakamaro mu kongera ubushyuhe bworoshye.Kuri elastomers ya thermoplastique, imiterere ya molekuline iba igizwe cyane cyane, kandi ubushyuhe bworoshye bwa elastomer nabwo bwiyongera mugihe uburemere bwa molekile bugereranije bwiyongereye.
Kuri elastomers ihuza polyurethane, ubucucike bwambukiranya bugira ingaruka zikomeye kurenza uburemere bwa molekile.Kubwibyo, mugihe ukora elastomers, kongera imikorere ya isocyanates cyangwa polyole birashobora gukora imiterere ihamye yumuriro wa chimique ihuza imiterere ya molekile zimwe na zimwe za elastique, cyangwa ugakoresha ibipimo bya isocyanate bikabije kugirango ube urwego ruhamye rwa isocyanate ruhuza umubiri wa elastique ni uburyo bukomeye bwo kunoza ubushyuhe, kurwanya solvent, nimbaraga za mashini za elastomer.
Iyo PPDI (p-phenyldiisocyanate) ikoreshwa nkibikoresho fatizo, kubera guhuza mu buryo butaziguye amatsinda abiri ya isocyanate nimpeta ya benzene, igice gikomeye cyakozwe gifite impeta ndende ya benzene, itezimbere ubukana bwigice gikomeye bityo ikazamura ubushyuhe bwo guhangana na elastomer.
Urebye kumubiri, ubushyuhe bworoheje bwa elastomers biterwa nurwego rwo gutandukana kwa microphase.Nk’uko amakuru abitangaza, ubushyuhe bworoshe bwa elastomers butarimo gutandukana na microphase buri hasi cyane, hamwe nubushyuhe bwo gutunganya hafi 70 only, mugihe elastomers ihura na microphase ishobora kugera kuri 130-150 ℃.Kubwibyo, kongera urwego rwo gutandukanya microphase muri elastomers nimwe muburyo bwiza bwo kunoza ubushyuhe bwabo.
Urwego rwa microphase itandukanya elastomers irashobora kunozwa muguhindura ugereranije uburemere bwa molekuline igabanije ibice byurunigi hamwe nibice bigize urunigi rukomeye, bityo bikazamura ubushyuhe bwabyo.Abashakashatsi benshi bemeza ko impamvu yo gutandukana kwa microphase muri polyurethane ari thermodynamic idahuye hagati yoroheje kandi ikomeye.Ubwoko bwurunigi rwagutse, igice gikomeye nibirimo, ubwoko bworoshye bwubwoko, hamwe na hydrogen ihuza byose bigira ingaruka zikomeye kuri yo.
Ugereranije no kwagura urunigi rwa diol, kwagura urunigi rwa diamine nka MOCA (3,3-dichloro-4,4-diaminodiphenylmethane) na DCB (3,3-dichloro-biphenylenediamine) bagize amatsinda menshi ya polar amino ester muri elastomers, kandi imigozi myinshi ya hydrogen irashobora gushirwaho hagati yingingo zikomeye, kongera imikoranire hagati yingingo zikomeye no kuzamura urwego rwo gutandukanya microphase muri elastomers;Ikwirakwizwa rya aromatic urunigi nka p, p-dihydroquinone, na hydroquinone ni ingirakamaro kubisanzwe no gupakira neza ibice bikomeye, bityo bigatuma microphase itandukanya ibicuruzwa.
Ibice bya amino ester byakozwe na aliphatic isocyanates bifite aho bihurira nibice byoroshye, bigatuma ibice byinshi bigoye gushonga mubice byoroshye, bikagabanya urugero rwo gutandukana kwa microphase.Ibice bya amino ester byakozwe na aromatic isocyanates bifite aho bihurira nibice byoroshye, mugihe urwego rwo gutandukanya microphase ruri hejuru.Polyolefin polyurethane ifite imiterere yo gutandukanya microphase hafi yuzuye bitewe nuko igice cyoroshye kidakora imigozi ya hydrogène kandi imigozi ya hydrogène ishobora kugaragara mugice gikomeye.
Ingaruka zo guhuza hydrogène ku ngingo yoroshye ya elastomers nayo irahambaye.Nubwo polyeter na karubone mubice byoroshye bishobora gukora umubare munini wa hydrogène hamwe na NH mugice gikomeye, byongera ubushyuhe bworoheje bwa elastomers.Byemejwe ko imigozi ya hydrogen ikomeza kugumana 40% kuri 200 ℃.
02 Kubora
Amatsinda ya ester ya Amino ahura nibi bikurikira kubushyuhe bwinshi:
- RNHCOOR - RNC0 HO-R
- RNHCOOR - RNH2 CO2 ene
- RNHCOOR - RNHR CO2 ene
Hariho uburyo butatu bwingenzi bwo kubora ubushyuhe bwibikoresho bishingiye kuri polyurethane:
Gukora isocyanates yumwimerere na polyoli;
.Acide Amino ibora muri amine imwe y'ibanze na dioxyde de carbone:
③ Shiraho 1 amine ya kabiri na dioxyde de carbone.
Kubora k'ubushyuhe bwa karbamate:
Aryl NHCO Aryl, ~ 120 ℃;
N-alkyl-NHCO-aryl, ~ 180 ℃;
Aryl NHCO n-alkyl, ~ 200 ℃;
N-alkyl-NHCO-n-alkyl, ~ 250 ℃.
Ubushyuhe bwumuriro wa aminide acide ifitanye isano nubwoko bwibikoresho byo gutangira nka isocyanates na polyol.Aliphatic isocyanates iruta isocyanates ya aromatic, mugihe alcool ibinure iruta alcool.Nyamara, ubuvanganzo buvuga ko ubushyuhe bwangirika bwumuriro wa alifatique amino acide iri hagati ya 160-180 and, naho iyitwa acide aminide acide iri hagati ya 180-200 ℃, ibyo bikaba bidahuye namakuru yavuzwe haruguru.Impamvu irashobora kuba ifitanye isano nuburyo bwo kwipimisha.
Mubyukuri, alifatique CHDI (1,4-cyclohexane diisocyanate) na HDI (hexamethylene diisocyanate) ifite ubushyuhe bwiza kuruta ubukana bwa MDI na TDI.Cyane cyane trans CHDI ifite imiterere ihuriweho yamenyekanye nka isocyanate irwanya ubushyuhe cyane.Polyurethane elastomers yateguwe muri yo ifite uburyo bwiza bwo gukora neza, irwanya hydrolysis nziza, ubushyuhe bworoshe cyane, ubushyuhe buke bwikirahure, hystereze nkeya yumuriro, hamwe na UV irwanya cyane.
Usibye itsinda rya amino ester, polyurethane elastomers ifite andi matsinda akora nka urea formate, biuret, urea, nibindi. Aya matsinda arashobora kwangirika kwubushyuhe mubushyuhe bwinshi:
NHCONCOO - (alifatique urea formate), 85-105 ℃;
- NHCONCOO - (formati ya urea ya aromatic), ku bushyuhe bwa 1-120 ℃;
- NHCONCONH - (alifatique biuret), ku bushyuhe buri hagati ya 10 ° C na 110 ° C;
NHCONCONH - (biuret aromatic), 115-125 ℃;
NHCONH - (alifatique urea), 140-180 ℃;
- NHCONH - (urea aromatic urea), 160-200 ℃;
Impeta ya Isocyanurate> 270 ℃.
Ubushyuhe bwo kubora bwa biuret na urea bushingiye kumiterere ni munsi cyane ugereranije na aminoformate na urea, mugihe isocyanurate ifite ubushyuhe bwiza bwumuriro.Mu musaruro wa elastomers, isocyanates irenze irashobora gukomeza kwitwara hamwe na aminoformate na urea byakozwe kugirango habeho urea ishingiye kuri biuret hamwe na biuret ihuza imiterere.Nubwo zishobora kunoza imiterere ya elastomers, ntizihinduka cyane kubushyuhe.
Kugirango ugabanye amatsinda adahinduka yumuriro nka biuret na urea bigizwe na elastomers, birakenewe ko dusuzuma igipimo cyibikoresho fatizo nibikorwa byakozwe.Ikigereranyo kirenze urugero cya isocyanate kigomba gukoreshwa, kandi ubundi buryo bugomba gukoreshwa uko bishoboka kwose kugirango ubanze ugire impeta ya isocyanate igice cyibikoresho fatizo (cyane cyane isocyanates, polyol, hamwe niyagura urunigi), hanyuma ubyinjize muri elastomer ukurikije inzira zisanzwe.Ubu bwahindutse uburyo bukoreshwa cyane mukubyara ubushyuhe bwumuriro na polyurethane elastomers.
03 Hydrolysis hamwe na okiside yumuriro
Polyurethane elastomers ikunda kwangirika kwubushyuhe mubice byabo bikomeye hamwe nimpinduka zijyanye nimiti mubice byoroheje kubushyuhe bwinshi.Polyester elastomers ifite amazi mabi kandi ikunda hydrolyze kubushyuhe bwinshi.Ubuzima bwa serivisi ya polyester / TDI / diamine irashobora kugera kumezi 4-5 kuri 50 ℃, ibyumweru bibiri gusa kuri 70 ℃, niminsi mike hejuru ya 100 ℃.Imigozi ya Ester irashobora kubora muri acide na alcool ihuye nigihe ihuye namazi ashyushye hamwe na parike, kandi amatsinda ya urea na amino ester muri elastomers nayo ashobora guhura na hydrolysis:
ICYUMWERU H20- → ICYUBAHIRO CYIZA
Inzoga
RNHCONHR imwe H20- → RXHCOOH H2NR -
Ureamide
Imwe muri RNHCOOR-H20- → INYUMA ya RNCOOH -
Amino ikora ester Amino ikora inzoga
Elastomers ishingiye kuri polyether ifite umutekano muke wa okiside yumuriro, hamwe na elastomers ishingiye kuri ether α- hydrogène kuri atome ya karubone iba okiside byoroshye, ikora hydrogen peroxide.Nyuma yo kubora no gutobora, ibyara okiside ya okiside na hydroxyl radicals, amaherezo ikabora ibimera cyangwa aldehydes.
Poliester zitandukanye ntizifite ingaruka nke kubirwanya ubushyuhe bwa elastomers, mugihe polyeter zitandukanye zigira ingaruka runaka.Ugereranije na TDI-MOCA-PTMEG, TDI-MOCA-PTMEG ifite imbaraga zingana zingana na 44% na 60% mugihe ufite imyaka 121 ℃ muminsi 7, iyanyuma ikaba nziza cyane kurenza iyambere.Impamvu irashobora kuba nuko molekile ya PPG ifite iminyururu yamashami, idafasha gahunda isanzwe ya molekile ya elastique kandi igabanya ubushyuhe bwumubiri wumubiri.Itondekanya ryumuriro wa polyeter ni: PTMEG> PEG> PPG.
Andi matsinda akora muri polyurethane elastomers, nka urea na karbamate, nayo ahura na okiside na hydrolysis.Nyamara, itsinda rya ether nitsinda ryoroshye okiside, mugihe ester groupe hydrolyzed byoroshye.Urutonde rwa anti -xydeant na hydrolysis irwanya ni:
Igikorwa cya Antioxidant: esters> urea> karbamate> ether;
Kurwanya Hydrolysis: ester
Kugirango tunonosore imbaraga za okiside ya polyurethane hamwe na hydrolysis irwanya polyester polyurethane, inyongeramusaruro nazo zongerwamo, nko kongeramo 1% antioxydants ya fenolike Irganox1010 kuri PTMEG polyether elastomer.Imbaraga zingana ziyi elastomer zirashobora kwiyongera inshuro 3-5 ugereranije na antioxydants (ibisubizo byikizamini nyuma yo gusaza kuri 1500C kumasaha 168).Ariko ntabwo antioxydeant yose igira ingaruka kuri elastomers ya polyurethane, gusa fenolike 1rganox 1010 na TopanOl051 (antioxydeant ya fenolike, ibangamira urumuri rwa amine, urwego rwa benzotriazole) igira ingaruka zikomeye, kandi iyambere niyo nziza, birashoboka kuko antioxydants ya fenolike ifitanye isano na elastomers.Ariko rero, kubera uruhare rukomeye rwamatsinda ya hydroxyl ya fenolike muburyo bwo gutuza antioxydants ya fenolike, kugirango hirindwe reaction n "gutsindwa" kwiri tsinda rya hydroxyl hydroxyl hamwe nitsinda rya isocyanate muri sisitemu, ikigereranyo cya isocyanate na polyol ntigikwiye kuba binini cyane, na antioxydants igomba kongerwaho prepolymers hamwe niyagura urunigi.Niba wongeyeho mugihe cyo gukora prepolymers, bizagira ingaruka cyane kumikorere.
Inyongeramusaruro zikoreshwa mu gukumira hydrolysis ya polyester polyurethane elastomers ahanini ni karbodiimide, ifata hamwe na acide karubike ya acide iterwa na ester hydrolysis muri molekile ya polyurethane elastomer kugirango ikore ibikomoka kuri acile urea, bikarinda hydrolysis.Kwiyongera kwa karbodiimide mugice kinini cya 2% kugeza 5% birashobora kongera amazi ya polyurethane inshuro 2-4.Mubyongeyeho, tert butyl catechol, hexamethylenetetramine, azodicarbonamide, nibindi nabyo bigira ingaruka zimwe na zimwe zo kurwanya hydrolysis.
04 Ibikorwa nyamukuru biranga
Polyurethane elastomers isanzwe ikora kopi nyinshi, hamwe numurongo wa molekile ugizwe nibice byoroshye hamwe nubushyuhe bwikirahure munsi yubushyuhe bwicyumba hamwe nibice bikaze hamwe nubushyuhe bwikirahure burenze ubushyuhe bwicyumba.Muri byo, oligomeric polyol ikora ibice byoroshye, mugihe diisocyanates hamwe nuduce duto twa molekile twagura ibice bikomeye.Imiterere yashyizwemo ibice byoroshye kandi bigoye byerekana imikorere yihariye:
.Polyurethane elastomers irashobora kugera munsi ya Shaoer A10 no hejuru nka Shaoer D85, bitabaye ngombwa ubufasha bwuzuye;
(2) Imbaraga nini na elastique birashobora gukomeza kubungabungwa muburyo butandukanye;
(3) Kurwanya kwambara neza, inshuro 2-10 za reberi karemano;
(4) Kurwanya cyane amazi, amavuta, n'imiti;
.
(6) Kurwanya ubushyuhe buke buke, hamwe n'ubushyuhe buke buri munsi -30 ℃ cyangwa -70 ℃;
.
(8) Ibyiza biocompatibilité nibintu birwanya anticoagulant;
(9) Gukoresha amashanyarazi meza cyane, kurwanya imashini, no gukomera kwa UV.
Polyurethane elastomers irashobora gushirwaho hakoreshejwe inzira imwe nka reberi isanzwe, nka plastike, kuvanga, hamwe n’ibirunga.Birashobora kandi kubumbwa muburyo bwa reberi y'amazi usuka, gushushanya hagati, cyangwa gutera.Birashobora kandi gukorwa mubikoresho bya granulaire hanyuma bigakorwa hakoreshejwe inshinge, gusohora, kuzunguruka, guhumeka, nibindi bikorwa.Muri ubu buryo, ntabwo itezimbere imikorere yakazi gusa, ahubwo inatezimbere uburinganire bwukuri nigaragara ryibicuruzwa
Igihe cyo kohereza: Ukuboza-05-2023