Okuthiwa okubizwa ngokuthiPolyurethaneIngabe isifinyezo se-polyurethane, esakhiwa ukusabela kwama-polysocyates nama-polyols, futhi sinamaqembu amaningi aphindaphindwayo (- NH-CO-O -) ku-chain molecular. Kuma-poltherethane resins angokoqobo, ngaphezu kweqembu le-Amino Ester, kukhona namaqembu anjenge-urea ne-biuret. Ama-polyol angowama-molecule amade anama-hydroxyl ngamaqembu e-hydroxyl ekugcineni, abizwa ngokuthi "izingxenye ezithambile ze-chain", kanti ama-polyisocyanates abizwa ngokuthi "izingxenye ezinzima".
Phakathi kwama-polyurethane resen akhiqizwa izingxenye ezithambile nezilukhuni, amaphesenti amancane kuphela ama-amino acid esters, ngakho-ke kungahle kungafanele ukubabiza nge-polyurethane. Ngomqondo obanzi, i-polyurethane isengezo se-isocyanate.
Izinhlobo ezahlukene ze-isocyanates ziphendule ngamakhompiyutha e-polyhydroxy ukukhiqiza izakhiwo ezahlukahlukene ze-polyurethane, ngaleyo ndlela zithola izinto ze-polymer ezinezinto ezahlukene, njengamapulasitiki, ama-adhesing, njll.
I-Polyurethane rubber ingeyaluhlobo olukhethekile lwenjoloba, elenziwa ngokuphendula ama-polythelekile noma i-polyester nge-isocyanate. Kunezinhlobo eziningi ngenxa yezinhlobo ezahlukahlukene zezinto zokusetshenziswa, izimo zokuphendula, nezindlela zokuwela. Ngokombono wesakhiwo samakhemikhali, kunezinhlobo ze-polyester kanye ne-polyther, futhi kusuka ekuhlolweni kwendlela yokusebenza, kunezinhlobo ezintathu: uhlobo lokuxuba, uhlobo lwe-thermoplastic, nohlobo lwe-thermoplastic.
I-Synthetic Polyurethane i-rubber ngokuvamile ihlanganiswe ngokuphendula i-polyerter noma i-polythelekile nge-diisocyate ukwakha i-molecular isisindo esiphakeme sokuphendula i-polymer ukukhiqiza i-polymer ephezulu ye-molecular. Ngemuva kwalokho, kufakwa ama-ejenti afanelekile awela futhi afudumele ukuze akwephule, abe irabha elivuselelayo. Le ndlela ibizwa nge-prefermerization noma indlela yezinyathelo ezimbili.
Kungenzeka futhi ukusebenzisa indlela yesinyathelo esisodwa - ngokuqondile ukuxuba okuqondile i-polyester noma ama-polyther nama-diisocyanates, abangenisi bama-chain, kanye nama-ejenti wokuwela ukuqalisa ukusabela futhi akhiqize i-polyurethane rubber.
Ingxenye ye-A-e-TPU Molekyuli yenza amaketanga we-macromolecular alula ukujikeleza, enikeza i-polyurethane irabha ngokunwebeka okuhle kanye nephuzu lokuthambisa kwesibili kanye nokunciphisa ubulukhuni bawo namandla emishini. Ingxenye ye-B izobopha ukujikeleza kwamaketanga ama-macromolecular, okwenza iphuzu lokuthambisa kanye nephuzu lokuguqulwa kwesibili le-polymer ukuze likhuphuke, okuphumela ekubukeni kobulukhuni namandla emishini, kanye nokuncipha kokuqina. Ngokushintsha isilinganiso se-molar phakathi kwe-A no-B, i-TPUS enezakhiwo ezahlukahlukene zemishini zingakhiqizwa. Ukwakheka okuxhumanisayo kwe-TPU akumele kubhekwe ngokuxhumanisa okuyisisekelo, kepha futhi nokuxhumeka kwesikhashana okwakhiwe ngama-hydrogen bond phakathi kwama-molecule. Isibopho sokuqala esixhumayo se-polyurethane sihlukile kwisakhiwo se-vulcanization yenjoloba ye-hydroxyl. Iqembu layo le-Amino Ester, iqembu le-urea, iqembu elisebenzayo namanye amaqembu asebenzayo ahlelwe ngengxenye ejwayelekile ye-Curid Chain, okuholela esakhiweni esijwayelekile se-Rubber, esinokumelana kahle nezakhiwo ezinhle kakhulu. Okwesibili, ngenxa yokuba khona kwamaqembu amaningi asebenzayo abumbene afana ne-Urea noma ama-carbamate enjoloba, izibopho zesibili ze-hydrogen zakhiwa ngama-hydrogen bond anamandla aphezulu anamandla okusebenza nge-polyurethane rabber. Ukuxhumanisa kwesikhashana kwe-polyurethane kunika amandla ama-polyurethane enjoloba ukuze athole ama-elastomers aphezulu ngakolunye uhlangothi, ngakolunye uhlangothi, lokhu kuxhumeka okuphambanisayo akuxhunyaniswa ngokweqiniso, okwenza kube nokuxhumeka ngokuxhumeka ngokweqiniso. Isimo esixhumanisayo sincike ekushiseni. Njengoba izinga lokushisa lenyuka, lokhu kuxhumanisa kancane kancane kancane kuyaba buthaka futhi kunyamalale. I-polymer inokwibizi oluthile futhi ingabekwa ngaphansi kokulungiswa kwe-thermoplastic. Lapho amazinga okushisa encipha, lokhu kuxhuma kancane kancane kuthola kabusha futhi kuphinde kuphinde kuphinde kuphinde kuphinde kuphinde kubuye amafomu namafomu. Ukungezwa kwenani elincane le-filler kukhulisa ibanga phakathi kwama-molecule, kwenza buthaka amandla okwenza izibopho ze-hydrogen phakathi kwama-molecule, futhi kuholele ekunciphiseni okukhulu ngamandla. Ucwaningo selukhombisile ukuthi ukuhleleka kwamaqembu ahlukahlukene asebenza e-polyurethane enjoloba kusuka phezulu kuya phansi: ester, ether, u-urea, carbamate, kanye ne-bieret. Ngesikhathi senqubo yokuguga ye-polyurethane rabber, isinyathelo sokuqala ukwephulwa kwezibopho ezixhumanisa phakathi kwe-biuret ne-urea, kulandelwa ukwephulwa kwe-carbamate kanye ne-urea bond, okungukuthi, ukuqhekeka kwe-urea.
01 ukuthambisa
Ama-Polyurethane lastomers, njengezinto eziningi ze-polymer, ethambisa amazinga okushisa aphezulu kanye noshintsho kusuka esimweni sokunwebeka esimweni sokugeleza esisezingeni eliphakeme, okuholela ekunciphiseni okusheshayo kumandla emishini. Ngokombono wamakhemikhali, izinga lokushisa elithambisa lobuciko ikakhulukazi lincike ezintweni ezifana nokwakheka kwamakhemikhali, isisindo se-molecular esilinganayo, kanye nobuningi bokuwela.
Ngokuvamile, okwandisa isisindo se-molecular esihlobene, okwandisa ukuqina kwengxenye enzima (njengokungenisa i-benzene ring ku-molecule) kanye nokuqukethwe kwengxenye enzima, nokwandisa ubuningi be-crosslinking konke kuzuzisa izinga lokushisa lokushisa. Kwama-thermoplastic elastomers, isakhiwo samangqamuzana ikakhulukazi silayini, futhi izinga lokushisa elithambisa le-elastomer libuye likhuphuke lapho isisindo se-molecular sikhuphukile.
Okwe-polyurethane exhumene nalawo maastomers, ukuncipha kwabantu kunomthelela omkhulu kunesisindo esilinganayo se-molecular. Ngakho-ke, lapho ukhiqiza ama-lastomers, ukwanda ukusebenza kwama-isocyanates noma ama-polyols angakha isakhiwo esizinzile senethiwekhi yamakhemikhali angenamandla, noma ukusebenzisa izilinganiso ze-isocyanate ze-isocyanate ukuze kuthuthukiswe ukumelana nokushisa okunamandla, ukumelana nomoya kanye namandla emishini e-elastomer.
Lapho i-PPDI (P-PhenyLylliocyate) isetshenziswa njengento eluhlaza, ngenxa yokuxhumana okuqondile kwamaqembu amabili we-isocyanate kwi-benzene ring, i-hard arving inokuqukethwe kwe-benzene ephakeme, okuthuthukisa ukumelana kwengxenye enzima futhi kuthuthukisa ukumelana nokushisa kwe-elastomer.
Ngokombono womzimba, izinga lokushisa elithambisa lakwa-elastomers lincike ekuhlukanisweni kwemakrofasi. Ngokusho kwemibiko, izinga lokushisa elithambisa ama-lastomers angaphansi kwe-micropase liphansi kakhulu, linokushisa okungama-70 ℃ kuphela, kanti ama-elastomers ahlukaniswa ngemakrophasi angafinyelela ku-130-150 ℃. Ngakho-ke, ukwandisa izinga lokuhlukaniswa kwemakrophasizise kuma-elastomers kungenye yezindlela ezisebenzayo zokuthuthukisa ukumelana kwazo kokushisa.
Izinga le-microphase ahlukaniswe ama-lastomers angathuthukiswa ngokushintsha ukusatshalaliswa kwesisindo okuhlobene nama-chain izingxenye zokucwaninga nokuqukethwe kwezingxenye zamaketanga aqinile, ngaleyo ndlela kuthuthukise ukumelana nokushisa kwazo. Abaphenyi abaningi bakholelwa ukuthi isizathu sokuhlukaniswa kwemakrophase ePolyurethane ukungahambelani kwe-thermodynanom phakathi kwezingxenye ezithambile nezinzima. Uhlobo lwe-Chain Extender, ingxenye eqinile nokuqukethwe kwayo, uhlobo lwengxenye ethambile, kanye ne-hydrogen bonding bonke banomthelela omkhulu kukho.
Uma kuqhathaniswa nabanweli be-Diol Chain, abanweli bamakhethini we-Diamene afana neMoca (3,3-Dichloro-4,4-DiadinoRo-Biphenysenethane) ne-DCB (3,3-Dichloro-BiphenYenimine)) Kwakha ama-Hard izingxenye ezinzima nokuthuthukisa izinga lokuhlukaniswa kwemakromase ema-elastomers; Abakwa-Symmetric Anomatic Chain Extenders afana ne-P, P-Dihydroquone, futhi i-hydroquinone inenzuzo evamile nokupakishwa okuqinile kwezingxenye ezinzima, ngaleyo ndlela kuthuthukise ukuhlukaniswa kwemayrophase kwemikhiqizo.
Izingxenye ze-Amino Ester ezakhiwe ngama-aliphatic isocyanates zinokuhambisana okuhle nezingxenye ezithambile, okuholela ezingxenyeni ezinzima ngokwengeziwe ezihlukaniswe ezingxenyeni ezithambile, zinciphisa izinga lokuhlukaniswa kwemakrofoni. Izingxenye ze-Amino Ester ezakhiwe ngama-aromatic asocyanates zinokuhambisana okumpofu nezingxenye ezithambile, kanti izinga lokuhlukaniswa kwemakrophasi liphezulu. I-Polyolof Polyurethane inesakhiwo esicishe sahlukaniswa ngemakrophasizise esiphelele ngenxa yokuthi ingxenye ethambile ayibunzi izibopho ze-hydrogen kanye namabhondi we-hydrogen angenzeka kuphela engxenyeni enzima.
Umphumela we-hydrogen bonding endaweni ethambile yama-elastomers nayo ibalulekile. Yize ama-polyethers kanye nama-carbonyls engxenyeni ethambile angakha inani elikhulu lama-hydrogen bond nge-NH engxenyeni enzima, futhi kukhulisa izinga lokushisa elithambile lama-elatomers. Kuqinisekisiwe ukuthi izibopho ze-hydrogen zisagcina ama-40% ku-200 ℃.
02 ukubola okushisayo
Amaqembu e-Amino Ester abhekana nokuwohloka okulandelayo emazingeni okushisa aphezulu:
- rnhcoor - rnc0 ho-r
- RNHCOOR - RNH2 CO2 ENE
- RNHCOOR - RNHR CO2 ENE
Kunezindlela ezintathu eziphambili zokuwohloka okushisayo kwezinto zokwenziwa ezisekelwe kwePolyurethane:
① Ukwakha ama-isocyanates asekuqaleni nama-polyols;
②- I-oxygen bond ku-CH2 Base Breaks futhi ihlanganise ngesibopho esisodwa se-hydrogen ku-CH2 yesibili ukwakha ama-amino acid kanye nama-alkene. Ama-Amino acid abola abe yingxenye eyodwa ye-Amine eyinhloko ne-carbon dioxide:
③ Fomula i-Amine Esezingeni eliphakeme ne-Carbon Dioxide.
Ukubola okushisayo kwesakhiwo se-carbamate:
URely Nhco Arel, ~ 120 ℃;
I-N-ALKYL-NHCO-ArYL, ~ 180 ℃;
U-Ary Nhco N-Alkyl, ~ 200 ℃;
I-N-ALKYL-NHCO-N-ALKYL, ~ 250 ℃.
Ukuqina okushisayo kwama-amino acid espers kuhlobene nezinhlobo zezinto zokuqala njenge-isocyanates nama-polyols. I-Aliphatic isocyanates iphakeme kune-aromatic asocyanates, ngenkathi amafutha anolaka aphakeme kunokuphuza amakha. Kodwa-ke, izincwadi zibika ukuthi amazinga okushisa athembekile we-Aliphatic Amino Acid espers aphakathi kuka-160-180 ℃, nokuthi ama-Aromatic Amino Acid Esters aphakathi kuka-180-200 ℃, ongahambisani nedatha engenhla. Isizathu singahle sihlobene nendlela yokuhlola.
Eqinisweni, i-aliphatic CHDI (1,4-cyclohexane diisocyatate) ne-HDI (Hexamethylene Diisocyate) inokumelana okungcono kokushisa kunalokho okuvame ukusetshenziswa kwe-MDI ne-TDI. Ikakhulu i-Trans Chdi enesakhiwo esilinganiselwe sekwamukelwe njenge-isocyanate emelana ukushisa kakhulu. Ama-polyurethane lastomers alungiselelwe kusuka kuwo anokukhononda okuhle, ukumelana okuhle kwe-hydrolysis, izinga lokushisa eliphakeme, izinga lokushisa eliphansi le-glass, okushisa okushisayo, kanye nokuphikiswa okuphezulu kwe-UV.
Ngaphezu kweqembu le-Amino Ester, ama-polyurethane lastomers nawo anamanye amaqembu asebenzayo anjenge-urea ehlelekile, i-biuret, i-urea, njll. Lawa maqembu angakwazi ukuwohloka okuphezulu:
Nhconcoo - (i-aliphhatic urea yakha), 85-105 ℃;
- I-NHCONCOO - (I-Aromatic Urea ehle), ebangeni lokushisa le-1-120 ℃;
- NHCONCONCHH - (Aliphhatic Biuret), emazingeni okushisa asuka ku-10 ° C kuye ku-110 ° C;
Nhconconh - (I-Aromatic Biuret), 115-125 ℃;
NhConh - (i-aliphatic urea), 140-180 ℃;
- NHCONH - (Urea aromatic), 160-200 ℃;
I-Isocyanurate Ring> 270 ℃.
Ukushisa okuvumayo kwe-thermal ye-biuret kanye ne-urea esekelwe kuphansi kunalokho kwama-aminoformate kanye ne-urea, ngenkathi isocyanurate inokuqina okungcono kakhulu okushisayo. Ekwenziweni kwama-lastomers, ama-isocyates amaningi angaqhubeka nokuphendula nge-aminoformate eyakhiwe kanye ne-urea ukwakha e-Urea esuselwa ekwakhekeni kanye ne-biuret exhumene nezakhiwo ezixhumene ne-biuret. Yize zingathuthukisa izakhiwo zemishini zakwa-elastomers, azizinzi kakhulu ukushisa.
Ukunciphisa amaqembu angazinzile angenakuzinzizela anjenge-biuret ne-urea kwakheka kuma-elastomers, kuyadingeka ukucubungula isilinganiso sabo esibonakalayo kanye nenqubo yokukhiqiza. Izilinganiso ze-isocyanate ze-isocyanate kufanele zisetshenziselwe, futhi ezinye izindlela kufanele zisetshenziswe ngangokunokwenzeka ukuze ziqale zenzele izindandatho ze-isocyanate eziyingxenye ezintweni ezisetshenziswayo (ikakhulukazi isocyanates, ama-polyols, kanye ne-chain eledlule), bese ungenisa e-elastomer ngokuya ngezinqubo ezijwayelekile. Lokhu sekuyindlela esetshenziswa kakhulu yokukhiqiza ama-polyurethane larastomers amelana nokushisa.
I-03 hydrolysis kanye ne-themal oxidation
Ama-polyurethane lastomers athambekele ekuboleni okushisayo ezingxenyeni zawo ezinzima kanye nezinguquko ezihambelana namakhemikhali ezingxenyeni zawo ezithambile emazingeni okushisa aphezulu. Ama-polyester arastomers anokumelana kwamanzi ampofu nokuthambekela okunzima kakhulu kwe-hydrolyze emazingeni okushisa aphezulu. Impilo yenkonzo ye-polyester / TDI / i-diawoine ingafinyelela izinyanga ezingama-4-5 ku-50 ℃, amaviki amabili kuphela ngo-70 ℃, futhi izinsuku ezimbalwa ezingenhla kwe-100 ℃. Amabhondi e-Ester angabola abe ama-acid ahambisanayo kanye notshwala lapho kuvezwa ngamanzi ashisayo kanye nomusi, kanye namaqembu e-urea kanye ne-amino e-Ester e-elastomers nakho kungaphendula nge-hydrolys:
Rcoor H20- → RCOOH HOR
Utshwala be-Ester
Eyodwa rnhconhr one h20- → rxhcooh h2nr -
I-ereemide
I-RNHCOOR eyodwa-H20- → RNCOOH HOR -
I-Amino yakha u-Amino e-Amino yakha utshwala
Ama-allomers asuselwa ku-polythert anokuqina okungekho oxidation, nama-ether asuselwa ama-elastomers α- I-hydrogen ku-athomu yekhabhoni i-axidi exides kalula, yakha i-hydrogen peroxide. Ngemuva kokuwohloka okuqhubekayo nokuqina, kwakha ama-oxide ama-radicals kanye nama-hydroxyl radicals, ekugcineni abola abe amafomu noma ama-aldehydes.
Ama-polyester ahlukahlukene anomthelela omncane ekumelaneni nokushisa kwama-elastomers, kanti ama-polyethers ahlukene anethonya elithile. Uma kuqhathaniswa ne-TDI-Moca-Ptmeg, i-TDI-MoMA-PTMeg inesilinganiso sokugcina samandla esingu-44% no-60% ngokulandelana kwa-121 ℃ izinsuku eziyi-12, ngokugcina kungcono kakhulu kunangaphambili. Isizathu kungenzeka ukuthi ama-molecule e-PPG anamaketanga anamagatsha angenamikhono, angavumeli ukuhlelwa okujwayelekile kwama-molekyuli anwebekile futhi anciphise ukumelana nokushisa komzimba we-elastic. Umyalelo wokuqina we-polyethers yi: Ptmeg> PEG> PPG.
Amanye amaqembu asebenzayo kuma-polyurethane lastomers, njenge-urea ne-carbamate, futhi ahlukaniswe nge-oxidation kanye nokuphendula nge-hydrolys. Kodwa-ke, iqembu le-ether lilide kakhulu, ngenkathi iqembu le-Ester liyi-hydrolyzed kalula. Ukuhleleka kwe-antioxidant yabo ne-hydrolysis yile:
Umsebenzi we-antioxidant: Esters> Urea> Carbamate> ether;
Ukumelana ne-Hydrolysis: Ester
Ukwenza ngcono ukumelana ne-oxidation kwe-polytheap polyurethane kanye nokumelana ne-hydrolysis ye-polyester polyurethane, izengezo nazo, njengokungeza 1% Phenolic Antioxidant Irgang1010 kuya ku-PTMEG Polythert elatomer. Amandla ashubile aleli lastomer angakhushulwa ngezikhathi ezi-3-5 uma kuqhathaniswa nama-antioxidants (imiphumela yokuhlola ngemuva kokuguga ngo-1500c amahora angama-1500). Kepha akuwona wonke ama-antioxidant anomphumela kuma-polyurethane lastomers, kuphela i-phenolic 110 ne-topanol051 (Phenoctriole Antioxidant, futhi ongemuva kwe-antioxidants engcono kakhulu, mhlawumbe ngoba i-antioxidants enhle kakhulu, mhlawumbe ngoba i-antioxidants ye-phenolic inokuhambisana okuhle nama-elastomers. Kodwa-ke, ngenxa yeqhaza elibalulekile lamaqembu we-phenolic hydroxyl eshini yokuzinza ye-antioxidants ye-phenolic, ukuze agweme ukusabela kanye ne-isocolic hydroxyl group ngamaqembu we-isocols ane-polyols akufanele angezwe kuma-prepolymers kanye nabasanda kufika. Uma kungezwa ngesikhathi sokukhiqizwa kwama-prepolymers, kuzothinta kakhulu umphumela wokuqina.
Izithasiselo ezisetshenziselwa ukuvikela i-hydrolysis ye-polyester polyurethane ama-arastomers ikakhulukazi ama-carbodiimide acid, asabela ngama-acid e-carboxylide akhiqizwa ama-acyl hydrolysis ku-polyurethane elastomer molecule ukukhiqiza ama-acyl urea deriavatives ukukhiqiza i-acyl urea deriavatives, ukuvikela ama-hydrolysis aqhubeke. Ukungezwa kwe-carbodiimide engxenyeni enkulu ye-2% kuya ku-5% kungakhuphula ukuqina kwamanzi kwe-polyurethane izikhathi 2-4. Ngaphezu kwalokho, uTert Butyl Catechol, Hexamethyleteterramine, Azodicarbonamide, njll. Futhi yiba nemiphumela ethile ye-anti hydrolysis.
04 Izici Zokusebenza Eziphambili
Ama-Polyurethane lastomers ajwayelekile ama-copolymers ajwayelekile, anamaketanga amamolekyuli ahlanganiswe nezingxenye eziguqukayo ngokushisa kwengilazi okuphansi okuphansi kwamazinga okushisa egunjini kanye nokushisa kwengilazi okuphezulu. Phakathi kwazo, ama-polyols e-Oligomeric akha izingxenye eziguquguqukayo, ngenkathi ama-diisocyanates kanye nama-molecule chain anwebekile amafomu aqinile. Ukwakheka okushumekiwe kwezingxenye eziguquguqukayo neziqinile ze-chain chain kunquma ukusebenza kwazo okuhlukile:
. Ama-polyurethane lastomers angafinyelela phansi njenge-shaoer A10 futhi aphezulu njenge-shaoer D85, ngaphandle kwesidingo sosizo lwe-filler;
(2) Amandla aphezulu nokuqina kusengagcinwa ngaphakathi kobulukhuni obuhlukahlukene;
(3) Ukumelana kahle nokugqokwa okuhle kakhulu, izikhathi ezi-2-10 zenjoloba yemvelo;
(4) ukumelana okuhle namanzi, uwoyela namakhemikhali;
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(7) Inomsebenzi omuhle kakhulu wokufakelwa kokufakwa, futhi ngenxa yokusebenza kwayo okuphansi okushisayo, inomphumela ongcono wokufakelwa ngokuqhathaniswa nenjoloba nepulasitiki;
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(9) Ukufakwa kukagesi okuhle kakhulu, ukumelana kokubumba, nokuqina kwe-UV.
Ama-polyurethane lastomers angakhiwa asebenzisa izinqubo ezifanayo njengenjoloba ezejwayelekile, njengokuhlela ngopulasitiki, ukuxubana kanye nokuvuselelwa. Zingabuye zibunjwe ngendlela yerabha eliwuketshezi ngokuthulula, ukuqiniswa kwe-centrifugal, noma ukufafaza. Zingakwazi futhi ngezinto zokwakha ama-granular futhi zakhiwa zisebenzisa umjovo, ukukhishwa, ukugoqa, ukushaya ngamandla, nezinye izinqubo. Ngale ndlela, hhayi nje kuphela ukuthuthukisa ukusebenza kahle komsebenzi, kepha futhi kuthuthukisa ukunemba okunobukhulu nokubukeka komkhiqizo
Isikhathi sePosi: Dec-05-2023