Izvo zvinonzipolyurethanendiko kupfupikiswa kwe polyurethane, iyo inoumbwa nekuita kwe polyisocyanates uye polyols, uye ine akawanda anodzokororwa amino ester mapoka (- NH-CO-O -) pane molecular cheni.Mune chaiyo yakagadzirwa polyurethane resin, kuwedzera kune amino ester boka, kunewo mapoka akadai seurea uye biuret.Polyols ndeyemamorekuru marefu ane hydroxyl mapoka kumagumo, anonzi "soft chain segments", nepo polyisocyanates ichinzi "hard chain segments".
Pakati pe polyurethane resins inogadzirwa neakapfava uye akaoma cheni zvikamu, chikamu chidiki chete cheamino acid esters, saka zvingave zvisina kukodzera kuvadaidza kuti polyurethane.Mupfungwa yakafara, polyurethane is a additive of isocyanate.
Mhando dzakasiyana dze isocyanates dzinoita nemakomboni epolyhydroxy kuti abudise zvimiro zvakasiyana-siyana zvepolyurethane, zvichibva zvawana zvinhu zvepolymer zvine zvinhu zvakasiyana, zvakaita semapurasitiki, rabha, machira, faibha, zvinonamira, nezvimwewo. Polyurethane rabha
Polyurethane rubber ndeyemhando yakakosha yerabha, iyo inogadzirwa nekuita polyether kana polyester ine isocyanate.Kune akawanda marudzi nekuda kwemhando dzakasiyana dzezvishandiso, maitiro ekuita, uye nzira dzekuyambuka.Kubva pane chimiro chemakemikari maonero, kune polyester uye polyether marudzi, uye kubva pakugadzirisa nzira yekuona, kune marudzi matatu: kusanganisa rudzi, casting type, uye thermoplastic type.
Synthetic polyurethane rubber inowanzogadzirwa nekuita linear polyester kana polyether ine diisocyanate kuti igadzire yakaderera mamorekuru uremu prepolymer, iyo inozoiswa pasi pecheni yekuwedzera reaction kuti igadzire yakakwira molecular huremu polymer.Zvadaro, zvakakodzera crosslinking agents anowedzerwa uye kupisa kuti kurapa, kuva vulcanized rabha.Iyi nzira inonzi prepolymerization kana nzira mbiri-nhanho.
Izvo zvakare zvinogoneka kushandisa imwe-nhanho nzira - kusanganisa zvakananga mutsara polyester kana polyether ine diisocyanates, cheni extender, uye crosslinking agents kuti atange kuita uye kugadzira polyurethane rubber.
Iyo A-segment mumamorekuru eTPU inoita kuti macromolecular cheni ive nyore kutenderera, ichipa polyurethane rubber nekunaka kwakanaka, ichidzikisa nzvimbo yekunyorovera uye yechipiri shanduko yepolymer, uye kuderedza kuoma kwayo uye simba remuchina.Iyo B-segment ichasunga kutenderera kwemaketani macromolecular, zvichiita kuti nzvimbo yekunyorovesa uye yechipiri shanduko yepolymer iwedzere, zvichikonzera kuwedzera kwekuoma uye kusimba kwemagetsi, uye kuderera kwekusagadzikana.Nekugadzirisa chiyero chemolar pakati peA neB, TPUs ane akasiyana mekiniki zvivakwa anogona kugadzirwa.Iyo muchinjika-inobatanidza chimiro cheTPU haifanire kungofunga yekutanga kuyambuka-kubatanidza, asiwo yechipiri muchinjiko-yekubatanidza inoumbwa nehydrogen zvisungo pakati pemamorekuru.Iyo yekutanga muchinjiko-inobatanidza bond ye polyurethane yakasiyana neiyo vulcanization chimiro chehydroxyl rabha.Boka rayo reamino ester, boka rebiuret, urea formate boka uye mamwe mapoka anoshanda akarongwa mune yakajairwa uye yakaparadzana rigid cheni segment, zvichikonzera yenguva dzose network chimiro cherabha, ine yakanakisa kupfeka kuramba uye zvimwe zvakanakisa zvimiro.Chechipiri, nekuda kwekuvapo kwemapoka akawanda akabatana anoshanda senge urea kana carbamate mapoka mu polyurethane rubber, ma hydrogen bond akaumbwa pakati pemacheni emamorekuru ane simba rakawanda, uye echipiri crosslinking bond akaumbwa ne hydrogen bonds anewo mhedzisiro yakakosha pazvinhu zve. polyurethane rubber.Secondary cross-linking inogonesa polyurethane rubber kuti ive nehunhu hwe thermosetting elastomers kune rumwe rutivi, uye kune rimwe divi, uku kuyambuka-kubatanidza hakuna kubatanidzwa chaiko, zvichiita kuti ive chaiyo yekubatanidza.Mamiriro ekubatanidza emuchinjikwa anoenderana nekupisa.Sezvo tembiricha inowedzera, uku kuyambuka-kubatanidza zvishoma nezvishoma kunopera uye kunyangarika.Iyo polymer ine imwe fluidity uye inogona kuiswa pasi pe thermoplastic processing.Kana tembiricha yadzikira, iyi cross-linking zvishoma nezvishoma inopora uye inoumba zvakare.Kuwedzerwa kwediki diki rekuzadza kunowedzera chinhambwe pakati pemamorekuru, kunoderedza kugona kuumba hydrogen zvisungo pakati pemamorekuru, uye zvinotungamira mukudzikira kwakanyanya kwesimba.Tsvagiridzo yakaratidza kuti kurongeka kwemapoka akasiyana anoshanda mupolyurethane rabha kubva kumusoro kusvika pasi ndeiyi: ester, ether, urea, carbamate, uye biuret.Munguva yekuchembera kwepolyurethane rubber, danho rekutanga kupatsanurwa kwezvisungo zvemuchinjiko pakati pebiuret neurea, zvichiteverwa nekutyoka kwecarbamate uye urea bond, ndiko kuti, kutyora kwecheni huru.
01 Kupfava
Polyurethane elastomers, senge zvinhu zvakawanda zvepolymer, zvinopfava pakupisa kwakanyanya uye shanduko kubva kune elastic state kuenda kune viscous flow state, zvichikonzera kuderera nekukurumidza kwesimba remagetsi.Kubva pakuona kwekemikari, kupfava tembiricha yekunyungudika kunonyanya kuenderana nezvinhu zvakaita sekuumbwa kwayo kwemakemikari, huremu hwemamorekuru, uye huremu hwekuyambuka.
Kazhinji, kuwedzera huremu hwema molecular, kuwedzera kuomarara kwechikamu chakaoma (sekuunza benzene ring mumorekuru) uye zviri mukati mechikamu chakaoma, uye kuwedzera kuchinjika density zvese zvinobatsira pakuwedzera tembiricha yekunyorova.Kune thermoplastic elastomers, chimiro chemolecular chinonyanya mutsara, uye tembiricha yakapfava ye elastomer inowedzerawo kana huremu hwemamorekuru hwawedzerwa.
Kune-cross-linked polyurethane elastomers, crosslinking density ine simba guru kudarika rema molecular huremu.Naizvozvo, kana uchigadzira elastomers, kuwedzera kushanda kweisocyanates kana polyols kunogona kuumba iyo thermally yakagadzikana network kemikari-yakabatana chimiro mune mamwe elastic mamorekuru, kana kushandisa yakawandisa isocyanate ratios kuumba yakagadzikana isocyanate cross-linking chimiro mumuviri elastic. nzira ine simba yekuvandudza kupisa kwekudzivirira, kupikisa kunyungudika, uye simba remagetsi re elastomer.
Kana PPDI (p-phenyldiisocyanate) inoshandiswa seyakagadzirwa, nekuda kwekubatana kwakananga kwemapoka maviri eisocyanate kune mhete yebenzene, chikamu chakaoma chakaumbwa chine mhete yepamusoro yebenzene, iyo inovandudza kusimba kwechikamu chakaoma uye nekudaro inowedzera. kupikisa kupisa kwe elastomer.
Kubva pakuona kwemuviri, kunyorova tembiricha ye elastomers kunoenderana nehuwandu hwekuparadzaniswa kwe microphase.Sekureva kwemishumo, tembiricha yekunyorovesa ye elastomers iyo isingaite microphase kupatsanurwa yakadzikira, ine tembiricha yekugadzira ingangoita 70 ℃, nepo elastomers inopinda microphase kupatsanurwa inogona kusvika 130-150 ℃.Naizvozvo, kuwedzera dhigirii rekuparadzaniswa kwemicrophase mu elastomers ndiyo imwe yenzira dzinoshanda dzekuvandudza kupisa kwavo kupisa.
Iyo dhigirii yekuparadzaniswa kwemicrophase ye elastomers inogona kuvandudzwa nekuchinja iyo yakaenzana molecular huremu kugovera kwezvikamu zveketani uye zvirimo zveakaomesesa cheni zvikamu, nekudaro kuwedzera kwavo kupisa.Vazhinji vaongorori vanotenda kuti chikonzero chekuparadzaniswa kwemicrophase mu polyurethane ndiko kusapindirana kwe thermodynamic pakati pezvikamu zvinyoro uye zvakaoma.Mhando yeketani yekuwedzera, chikamu chakaoma uye zvirimo, yakapfava chikamu chemhando, uye hydrogen bonding zvese zvine chekuita nazvo.
Zvichienzaniswa ne diol chain extenders, diamine chain extenders yakadai seMOCA (3,3-dichloro-4,4-diaminodiphenylmethane) uye DCB (3,3-dichloro-biphenylenediamine) inoumba mamwe mapoka epolar amino ester mu elastomers, uye mamwe mabhondi ehydrogen anogona kuumbwa pakati pezvikamu zvakaoma, kuwedzera kuwirirana pakati pezvikamu zvakaoma uye kuvandudza chiyero chekuparadzaniswa kwe microphase mu elastomers;Symmetric inonhuhwirira cheni inotambanudza senge p, p-dihydroquinone, uye hydroquinone inobatsira kune yakajairwa uye yakasimba kurongedza yezvikamu zvakaomarara, nekudaro kuvandudza microphase kupatsanurwa kwezvigadzirwa.
Zvikamu zveamino ester zvakaumbwa nealiphatic isocyanates zvine kuwirirana kwakanaka nezvikamu zvakapfava, zvichiita kuti zvikamu zvakaoma zvikuru zvinyunguduke muzvikamu zvakapfava, zvichideredza chiyero chekuparadzaniswa kwe microphase.Iwo amino ester segment akaumbwa neanonhuhwirira isocyanates ane hurombo kuenderana neakapfava zvikamu, nepo dhigirii rekuparadzaniswa kwemicrophase rakakwira.Polyolefin polyurethane ine inenge yakazara microphase yekuparadzanisa chimiro nekuda kwekuti chikamu chakapfava hachigadziri mabhondi ehydrogen uye mabhondi ehydrogen anogona kungoitika muchikamu chakaoma.
Mhedzisiro yehydrogen bonding pane yakapfava point ye elastomers yakakoshawo.Kunyangwe ma polyethers uye carbonyls muchikamu chakapfava chinogona kuumba nhamba huru yehydrogen zvisungo neNH muchikamu chakaoma, inowedzerawo kunyorova tembiricha ye elastomers.Izvo zvakasimbiswa kuti hydrogen zvisungo zvichiri kuchengetedza 40% pa200 ℃.
02 Kuora kwekupisa
Mapoka eAmino ester anoora zvinotevera pakupisa kwakanyanya:
- RNHCOOR – RNC0 HO-R
- RNHCOOR - RNH2 CO2 ene
- RNHCOOR – RNHR CO2 iye
Kune matatu makuru mafomu ekupisa kwekuora kwe polyurethane based zvinhu:
① Kugadzira yekutanga isocyanates uye polyols;
② α— Chisungo cheokisijeni pachigadziko cheCH2 chinotyoka uye chinosanganiswa neimwe hydrogen bond pane yechipiri CH2 kugadzira amino acids uye alkenes.Amino acids inoora kuita imwe yekutanga amine uye carbon dioxide:
③ Fomu 1 yechipiri amine uye carbon dioxide.
Thermal kuora kweiyo carbamate chimiro:
Aryl NHCO Aryl, ~ 120 ℃;
N-alkyl-NHCO-aryl, ~ 180 ℃;
Aryl NHCO n-alkyl, ~ 200 ℃;
N-alkyl-NHCO-n-alkyl, ~ 250 ℃.
Kugadzikana kwekupisa kweamino acid esters kune hukama nemhando dzekutanga zvinhu senge isocyanates uye polyols.Aliphatic isocyanates yakakwirira kudarika isocyanates inonhuhwirira, nepo madoro ane mafuta akakwira kupfuura madoro anonhuhwirira.Nekudaro, zvinyorwa zvinoshuma kuti tembiricha yekuora yealiphatic amino acid esters iri pakati pe160-180 ℃, uye iyo yeanonhuwirira amino acid esters iri pakati pe180-200 ℃, izvo zvisingaenderane nedata riri pamusoro.Chikonzero chinogona kunge chakabatana nemaitiro ekuedza.
Muchokwadi, aliphatic CHDI (1,4-cyclohexane diisocyanate) uye HDI (hexamethylene diisocyanate) vane kupisa kuri nani kupfuura kunowanzo shandiswa anonhuwirira MDI uye TDI.Kunyanya iyo trans CHDI ine symmetrical dhizaini yave ichizivikanwa seyakanyanya kupisa isocyanate.Polyurethane elastomers akagadzirirwa kubva mairi ane yakanaka processability, yakanakisa hydrolysis kuramba, yakanyanya kupfava tembiricha, yakaderera girazi tembiricha, yakaderera thermal hysteresis, uye yakakwira UV kuramba.
Pamusoro peboka reamino ester, polyurethane elastomers inewo mamwe mapoka anoshanda senge urea formate, biuret, urea, etc. Aya mapoka anogona kusangana nekupisa kwekupisa pakupisa kwakanyanya:
NHCONCOO - (aliphatic urea formate), 85-105 ℃;
- NHCONCOO - (inonhuhwirira urea formate), patembiricha ye1-120 ℃;
- NHCONCONH - (aliphatic biuret), patembiricha kubva pa10 ° C kusvika 110 ° C;
NHCONCONH - (inonhuwira biuret), 115-125 ℃;
NHCONH - (aliphatic urea), 140-180 ℃;
- NHCONH - (kunhuhwirira urea), 160-200 ℃;
Isocyanurate mhete> 270 ℃.
Iyo tembiricha yekuora yekupisa yebiuret uye urea based formate yakadzikira zvakanyanya pane iyo yeaminoformate uye urea, nepo isocyanurate ine yakanyanya kugadzikana yekupisa.Mukugadzira elastomers, yakawandisa isocyanates inogona kuwedzera kuita neyakaumbwa aminoformate uye urea kugadzira urea yakavakirwa formate uye biuret muchinjiko-yakabatana zvimiro.Kunyangwe ivo vachigona kuvandudza ma mechanics e elastomers, iwo haana kugadzikana zvakanyanya kupisa.
Kuti udzikise mapoka anopisa asina kugadzikana senge biuret uye urea formate mune elastomers, zvinodikanwa kuti utarise chiyero chavo chemidziyo uye maitiro ekugadzira.Yakawandisa isocyanate ratios inofanira kushandiswa, uye dzimwe nzira dzinofanirwa kushandiswa zvakanyanya sezvinobvira kutanga kuita partial isocyanate mhete mumwongo (kunyanya isocyanates, polyols, uye cheni extenders), uye wozopinza mu elastomer zvinoenderana nemaitiro akajairwa.Iyi ndiyo yave nzira inonyanya kushandiswa pakugadzira isingapise kupisa uye inodzivirira murazvo wepolyurethane elastomers.
03 Hydrolysis uye thermal oxidation
Polyurethane elastomers inotarirwa mukuwora kwekupisa muzvikamu zvawo zvakaoma uye inoenderana nekemikari shanduko muzvikamu zvawo zvakapfava pakupisa kwakanyanya.Polyester elastomers ine kusamira zvakanaka kwemvura uye tsika yakanyanya kuomesa hydrolyze pakupisa kwakanyanya.Hupenyu hwesevhisi hwepolyester/TDI/diamine hunogona kusvika 4-5 mwedzi pa50 ℃, mavhiki maviri chete pa70 ℃, uye mazuva mashoma chete pamusoro pe100 ℃.Ester zvisungo zvinogona kuora kuita zvinoenderana neasidhi uye madoro kana akaiswa mumvura inopisa uye muutsi, uye urea neamino ester mapoka mu elastomers anogona zvakare kuita hydrolysis reaction:
RCOOR H20- → RCOOH HOR
Ester doro
Imwe RNHCONHR imwe H20- → RXHCOOH H2NR -
Ureamide
Imwe RNHCOOR-H20- → RNCOOH HOR -
Amino formate ester Amino formate doro
Polyether based elastomers ine kusadzikama kwekupisa kwekupisa, uye ether based elastomers α- Iyo haidrojeni iri paatomu kabhoni inoiswa oxidized nyore, ichigadzira hydrogen peroxide.Mushure mekuwedzera kuora uye kutsemuka, inogadzira oxide radicals uye hydroxyl radicals, iyo inozopedzisira yaora kuita mafomati kana aldehydes.
Mapolyester akasiyana haaite zvishoma pakupikiswa kwekupisa kwe elastomers, nepo mapolyester akasiyana ane kumwe kurudziro.Kuenzaniswa neTDI-MOCA-PTMEG, TDI-MOCA-PTMEG ine simba rekuchengetedza simba re44% uye 60% zvakateerana pazera pa121 ℃ kwemazuva manomwe, iyo yekupedzisira iri nani zvakanyanya kupfuura yekare.Chikonzero chinogona kunge chiri chekuti PPG mamorekuru ane cheni dzemapazi, izvo zvisingaenderane neyakajairwa kurongeka kwemamorekuru mamorekuru uye kuderedza kupisa kwekudzivirira kwemuviri wakasimba.Iyo yekudziya kugadzikana kweiyo polyethers ndeye: PTMEG> PEG> PPG.
Mamwe mapoka anoshanda mu polyurethane elastomers, senge urea uye carbamate, zvakare anopinda oxidation uye hydrolysis maitiro.Zvisinei, boka reether ndiro rinonyanya kuokisiswa, nepo boka reester ndiro rinoita hydrolyzed zviri nyore.Kurongeka kweavo antioxidant uye hydrolysis kuramba ndeiyi:
Antioxidant chiitiko: esters> urea> carbamate> ether;
Hydrolysis kuramba: ester
Kuvandudza oxidation kuramba kwepolyether polyurethane uye hydrolysis kuramba kwepolyester polyurethane, zvinowedzera zvinowedzera, sekuwedzera 1% phenolic antioxidant Irganox1010 kuPTMEG polyether elastomer.Kusimba kwekusimba kweiyi elastomer kunogona kuwedzerwa ne3-5 nguva zvichienzaniswa nekusina antioxidants (yedzo mhinduro mushure mekuchembera pa1500C kwemaawa 168).Asi haisi yega yega antioxidant ine mhedzisiro pa polyurethane elastomers, chete phenolic 1rganox 1010 uye TopanOl051 (phenolic antioxidant, inhindered amine light stabilizer, benzotriazole complex) ine mhedzisiro yakakosha, uye yekutanga ndiyo yakanyanya kunaka, pamwe nekuti phenolic antioxidants ine yakanaka kuenderana ne elastomers.Nekudaro, nekuda kwebasa rakakosha remapoka ephenolic hydroxyl mukudzikamisa nzira ye phenolic antioxidants, kuitira kudzivirira kuita uye "kutadza" kweiyi phenolic hydroxyl boka rine isocyanate mapoka muhurongwa, chiyero cheisocyanates kune polyols haifanirwe kuve. yakakura kwazvo, uye antioxidants inofanira kuwedzerwa kune prepolymers uye cheni inotambanudza.Kana yakawedzerwa panguva yekugadzirwa kweprepolymers, inokanganisa zvakanyanya kugadzikana kwekuita.
Iwo anowedzera anoshandiswa kudzivirira hydrolysis yepolyester polyurethane elastomers anonyanya kusanganiswa necarbodiimide, ayo anoita necarboxylic acids anogadzirwa ne ester hydrolysis mu polyurethane elastomer mamorekuru kugadzira acyl urea derivatives, kudzivirira imwe hydrolysis.Kuwedzerwa kwecarbodiimide pachikamu chemazana che2% kusvika ku5% kunogona kuwedzera kugadzikana kwemvura ye polyurethane ne2-4 nguva.Pamusoro pezvo, tert butyl catechol, hexamethylenetetramine, azodicarbonamide, nezvimwewo zvinewo mamwe anti hydrolysis mhedzisiro.
04 Hunhu hwekuita maitiro
Polyurethane elastomers akajairwa akawanda block copolymers, ane mamorekuru cheni akaumbwa nezvikamu zvinochinjika zvine tembiricha yegirazi yakaderera pane tembiricha yekamuri uye zvikamu zvakaomarara zvine tembiricha yegirazi yakakwira kupfuura tembiricha yekamuri.Pakati pavo, oligomeric polyols inoumba zvikamu zvinoshanduka, nepo diisocyanates uye madiki mamorekuru ketani anotambanudza anoumba zvikamu zvakaomarara.Iyo yakamisikidzwa chimiro cheanochinjika uye akaomesesa cheni zvikamu zvinosarudza kuita kwavo kwakasiyana:
(1) Kuoma kwemhando yerabha yakajairwa kazhinji iri pakati peShaoer A20-A90, nepo kuoma kwepurasitiki kuri kuita Shaoer A95 Shaoer D100.Polyurethane elastomers inogona kusvika yakaderera seShaoer A10 uye yakakwira seShaoer D85, pasina kudiwa kwerubatsiro rwekuzadza;
(2) Simba guru uye elasticity inogona kuramba ichichengetwa mukati mekuoma kwakasiyana-siyana;
(3) Kunyanya kupfeka kuramba, 2-10 nguva yerabha yechisikigo;
(4) Kuramba kwakanakisa kumvura, mafuta, uye makemikari;
(5) Kupikisa kwepamusoro-soro, kuramba kuneta, uye kusagadzikana kwekudengenyeka, kwakakodzera kushandiswa kwepamusoro-frequency bending applications;
(6) Kudzikira kwakadzika-tembiricha kuramba, nekudzika-tembiricha brittleness pazasi -30 ℃ kana -70 ℃;
(7) Iyo ine yakanakisa kusevha mashandiro, uye nekuda kwekuderera kwayo kwekushisa conductivity, ine zvirinani zvekudzivirira zvichienzaniswa nerabha nepurasitiki;
(8) Yakanaka biocompatibility uye anticoagulant zvinhu;
(9) Yakanakisa magetsi ekudzivirira, mold kuramba, uye UV kugadzikana.
Polyurethane elastomers inogona kuumbwa ichishandisa maitiro akafanana seyakajairika rabha, senge plasticization, kusanganisa, uye vulcanization.Ivo vanogona zvakare kuumbwa muchimiro chemvura rabha nekudira, centrifugal molding, kana kupfapfaidza.Iwo anogona zvakare kugadzirwa kuita granular zvinhu uye kuumbwa uchishandisa jekiseni, extrusion, rolling, blowing molding, uye mamwe maitiro.Nenzira iyi, kwete chete inovandudza kushanda zvakanaka, asi zvakare inovandudza kurongeka uye kutaridzika kwechigadzirwa.
Nguva yekutumira: Zvita-05-2023