Lub npe hu uapolyurethaneyog cov lus luv ntawm polyurethane, uas yog tsim los ntawm cov tshuaj tiv thaiv ntawm polyisocyanates thiab polyols, thiab muaj ntau dua amere es-o -) ntawm cov molecular. Hauv cov synthesized polyurethane resins, ntxiv rau pawg amino estere ester, kuj muaj cov pawg xws li urea thiab biuret. Polyols muaj rau ntev-saw lwg me nrog hydroxyl pawg ", thaum Polyisocyanates yog hu ua" cov ntu sib txuas ".
Ntawm cov polyurethane cov nyiaj ua haujlwm tau tsim los ntawm cov saw mos thiab tawv me me yog cov tshuaj esino acid, yog li nws yuav tsis tsim nyog hu rau lawv polyurethane. Nyob rau hauv ib qho kev pom dav, polyurethane yog ib qho ntxiv ntawm isocyanate.
Ntau hom ntawm ISOCYANATES muaj kev ntxhov siab nrog polyhydroxy tebchaw los tsim cov khoom siv polyurethane, yog li tau txais cov roj hmab, cov roj hmab, cov nplaum, roj hmab
Polyurethane roj hmab yog rau hom tshwj xeeb roj hmab, uas yog ua los ntawm kev rov qab ua polyether lossis polyester nrog isocyanate. Muaj ntau ntau yam vim muaj ntau hom khoom siv raw, cov tshuaj tiv thaiv cov kev mob, thiab cov txheej txheem crosslinking. Los ntawm cov qauv tshuaj kho cov qauv kev pom, muaj hom tshuaj polyester thiab polyether, thiab los ntawm kev ua yeeb yam, muaj ntau hom, ua hom, thiab hom thermopicastic.
Cov Hluav Taws Xob Polyurethane Roj Hmab yog feem ntau synthesized los ntawm reacer li qub prepolymer, uas yog tom qab ntawd raug kaw cov kev xav tau los tsim cov tshuaj migh molecular hnyav polymer. Tom qab ntawd, tsim nyog crosslinking cov neeg sawv cev tau ntxiv thiab ua kom sov los kho nws, ua los ua cov roj hmab vulcanized. Hom no hu ua prepolymerization lossis ob-kauj ruam txoj kev.
Nws tseem muaj peev xwm siv ib txoj kev ib-qib - ncaj qha linear polyester lossis polyething cov tshuaj tiv thaiv, thiab cov roj hmab tsim cov roj hmab polyurethane.
Lub A-ntu hauv TPU lwg me me ua rau macromolecular rins yooj yim kom tig rov qab thiab cov roj hmab hloov pauv ntawm cov polymer, thiab txo nws lub hardness thiab kev siv zog. B-ntu yuav khi txoj kev sib hloov ntawm macromolecular chains, ua rau muaj kev nce ntxiv, ua rau muaj zog ntxiv, thiab muaj zog dua hauv elasticity. Los kho cov qhab nia cov nyiaj hniav puas nruab nrab ntawm a thiab b, tpus nrog cov khoom sib txawv tuaj yeem tsim. Tus ntoo khaub lig-txuas qauv ntawm TPU ntawm TPU yuav tsum tsis txhob txiav txim siab ua ntej kev sib txuas ua ntej, tab sis kuj tseem hais cov qauv sib txuas ntawm hydrogen ntawm cov lwg me me. Tus thawj tus ntoo khaub lig sib txuas ntawm polyurethane yog txawv ntawm vulcanization qauv ntawm hydroxyl roj hmab. Nws cov pab pawg Amenter Amino Ester, urea tsim cov pawg thiab cov roj carretal tsis tu ncua thiab lwm yam khoom siv tau zoo heev. Thib ob, vim muaj ntau pab pawg sib txuas lus xws li cov roj hmab uas muaj zog los ntawm cov roj hmab uas muaj zog, thiab cov roj hmab theem nrab ntawm cov khoom ntawm cov roj hmab polyurethane. Cov hneev taw txhuas sib txuas rau cov yam ntxwv ntawm thermosetting elastomers ntawm ib sab, thiab ntawm qhov kev sib txuas no tsis muaj sib txuas, ua rau nws mus sib txuas ntawm virtual. Qhov kev sib txuas hla kev sib txuas yog nyob ntawm qhov kub. Raws li qhov ntsuas kub nce ntxiv, qhov kev sib txuas no sib txuas zuj zus zuj zus thiab ploj mus. Cov polymer muaj qee yam kev ua kom pom tseeb thiab tuaj yeem raug rau thermoplastic ua. Thaum qhov kub nyhiab, qhov kev sib txuas no maj mam rov qab thiab cov ntaub ntawv dua. Qhov sib ntxiv ntawm cov tub lim dej ua kom muaj kev ncua deb ntawm cov kev ua kom dej thiab ua kom muaj cov khoom siv hydrogen ntawm cov lwg me me, thiab ua rau kom muaj lub zog ntse. Kev tshawb fawb tau pom tias kev txiav txim ntawm cov pab pawg ua haujlwm hauv ntau pab pawg polyurethane los ntawm qib siab yog: ester, ester, estea, thiab biuret. Thaum lub sij hawm laus ntawm polyurethane roj hmab, thawj kauj ruam yog qhov tawg ntawm cov biuret thiab urea, ua raws li cov carbamate thiab urea bonds, uas yog, lub saw hlau tseem ceeb.
01 softening
Polyurethane elastomers, zoo li ntau cov ntaub ntawv ntawm polymer, muag muag ntawm lub xeev loj thiab kev hloov pauv ntawm lub xeev txaus ntshai, ua rau muaj kev txo qis hauv kev siv zog. Los ntawm kev xav tau tshuaj lom neeg, qhov muag muag ntawm elasticity feem ntau yog nyob ntawm yam xws li nws cov tshuaj lom neeg muaj pes tsawg leeg, thiab qhov sib piv ntawm cov ntom ntom ntom.
Feem ntau hais lus, nce qhov hnyav txheeb ze molecular hnyav, nce zuj zus ntawm lub nplhaib benzene) thiab ntxiv rau cov kev sib tw ua rau lub zog benzene) thiab nce cov txiaj ntsig zoo nkauj yog txhua qhov muaj txiaj ntsig zoo ntxiv rau kev ua kom tau soften kub. Rau lub thermoplastic elastomers, cov qauv molecular feem ntau yog linear, thiab cov muag muag ntawm Elastomer kuj nce ntxiv thaum tus txheeb ze lub cev hnyav yog nce.
Rau tus ntoo khaub lig-txuas Polyurethane Elastomers, Crosslinking ntom muaj qhov hnyav tshaj qhov txheeb ze molecular hnyav. Yog li ntawd, thaum kev tsim khoom elastomers, ua haujlwm ntau ntawm isocyanates ib txwm muaj kev sib txuas ua ke los txhim kho cov qauv hluav taws xob sib txuas, thiab siv zog ntawm lub Elastomer.
Thaum ppdi (p-phenyldiisocyanate) yog siv los ua cov khoom sib txuas ntawm Benzene, vim yog cov khoom sib txuas ntawm Benzene, uas txhim kho cov txheej txheem Benzene, uas txhim kho cov txheej txheem Benzene, uas tau txhim kho cov khoom siv nyuaj thiab yog li txhim kho cov kub ua ntej ntawm Elastomer.
Los ntawm lub tswv yim lub cev, qhov soquening so ntawm elastomers nyob ntawm cov degree ntawm micropheation sib cais. Raws li cov lus ceeb toom, qhov muag kub ntawm Elastomers uas tsis dhau qhov kev sib cais microphease yog tsawg heev, thaum muaj kev sib cais microphisase tuaj yeem ncav cuag 130-150 ℃. Yog li ntawd, nce qib ntawm micropheation sib cais hauv elastomers yog ib txoj hauv kev zoo los txhim kho lawv cov cua sov tsis kam txhim kho.
Kev faib tawm microphease ntawm elastomers tuaj yeem txhim kho los ntawm kev hloov pauv cov kab sib txuas thiab cov ntsiab lus ntawm cov ntu txhav, yog li txhim kho lawv cov kub ua kom tsis kam. Cov kws tshawb nrhiav feem ntau ntseeg tias vim li cas rau microphone sib cais hauv polyurethane yog thermodynamic tsis sib xws ntawm cov mos mos thiab tawv ntu. Hom kev sib txuas txuas, ntu nyuaj thiab cov ntsiab lus, hom muag muag, thiab hydrogen khi uas txhua tus muaj qhov cuam tshuam loj rau nws.
Piv nrog Diol saw Extenders, cov tub sab tub yeeb ncuab xws li moca (3,3-dochloro-4,3-diamenporenmethans) thiab ntau dua cov pawg ntawm cov ntu nyuaj thiab txhim kho cov Qib ntawm micropheation sib cais hauv Elastomers; Symmetric cov tshuaj uas nthuav dav xws li P, P-Dihydroquinone, thiab hydroquinone muaj txiaj ntsig zoo rau cov ntu nyuaj, yog li kev txhim kho microphase sib cais ntawm cov khoom.
Cov Amino Ester ntu tsim los ntawm aliphatic Isocyanates muaj kev sib raug zoo nrog cov ntu muag, txo qis cov qib ntawm microphuation sib cais. Amino Ester ntu tsim los ntawm cov neeg muaj ntxhiab isocyanates muaj kev sib xyaw tsis zoo nrog cov nqaj mos, thaum cov degree ntawm microphuation sib cais yog siab dua. PolyolinQuin Polyurethane muaj yuav luag microphse sib cais cov qauv kev sib cais thiab cov khoom lag luam hydrogen tsis yog tshwm sim hauv ntu nyuaj.
Cov nyhuv ntawm hydrogen khi rau ntawm cov khoom muag muag ntawm Elastomers kuj tseem ceeb heev. Txawm hais tias cov polyether thiab carbons hauv ntu muag muag tuaj yeem tsim cov pob zeb hydrogen ntau nrog NH hauv cov plaub ntug nyuaj, nws kuj tseem ua kom cov mos mos ntawm elastomers. Nws tau raug lees tias hydrogen bonds tseem khaws 40% ntawm 200 ℃.
02 thermal decomposition
Amino ester pawg uas tau txais kev txiav txim siab hauv qab no ntawm qhov kub siab:
- rnhor - rnc0 ho-r
- rnhor - rnh2 ce2 ene
- rnhor - rnhr co2 ene
Muaj peb cov ntaub ntawv tseem ceeb ntawm thermal decomposition ntawm polyurethane raws cov ntaub ntawv:
① Ua tus thawj Isocyanates thiab polyols;
Α α- Cov kev sib tw oxygen rau ntawm CH2 RAWS LI thiab sib xyaw nrog ib tus hydrogen bond on thib ob CH2 los ua cov amino acids thiab alkenes. Cov amino acids decompose rau ib lub amine thawj thiab carbon dioxide:
Daim ntawv 1 theem nrab amine thiab carbon dioxide.
Thermal Decomposition ntawm Carbamate Qauv:
Aryl NHCO ARYR, ~ 120 ℃;
N-alkyl-nhco-aryl, ~ 180 ℃;
Aryl NHCO N-Alkyl, ~ 200 ℃;
N-alkyl-nhco-n-alkyl, ~ 250 ℃.
Lub thermal stability ntawm amino acid isters muaj feem xyuam rau cov hom pib cov ntaub ntawv xws li Isocyanates thiab Polyols. Aliphatic Isocyanates yog siab dua cov neeg muaj yees, thaum muaj cawv roj ntau dua li cov cawv txiv hmab txiv ntoo. Txawm li cas los xij, cov ntaub ntawv qhia txog cov thermal decomposition kub ntawm aliphatic amino acid isters yog nruab nrab ntawm 180-200 ℃, uas yog tsis sib xws nrog cov ntaub ntawv saum toj no. Qhov laj thawj yuav cuam tshuam nrog txoj kev xeem.
Qhov tseeb, aliphaatic chdi (1,4-cyclohexane diisocyanate) thiab HDI (Hoxamethylene Diisocyanate) Tsis tau siv cov cua sov zoo dua li cov muaj ntxhiab MDI thiab TDI. Tshwj xeeb yog Trans chadi nrog cov qauv sib xws tau raug lees paub tias yog feem ntau cov cua sov-resistant isocyanate. Polyurethane elastomers npaj los ntawm nws muaj cov txheej txheem hydrolysis zoo, siab softening kub, qis thermal hysteresis, thiab siab UV tsis kam.
Ntxiv nrog rau pawg amino estere ester, polyurethane elastomers kuj muaj lwm pab pawg xws li urea, urea, urea, etea, etea, etea, etea.
NHCORCoo - (Aliphatic urea tsim), 85-105 ℃;
- Nhconcoo - (cov tshuaj pleev xim uas muaj ntxhiab urea), ntawm qhov kub thiab txias ntawm 1-120 ℃;
- Nhaconh - (Aliphatic biuret), ntawm qhov kub xws li los ntawm 10 ° C rau 110 ° C;
NHConConH - (cov biuromet), 115-125 ℃;
NHCONH - (Aliphatic urea), 140-180 ℃;
- NHCONH - (muaj ntxhiab urea), 160-200 ℃;
Ntiv nplhaib isocyanurate> 270 ℃.
Lub thermal decomposition kub ntawm biuret thiab urea raws li qhov qis dua uas yog aminoformate thiab urea, thaum ortocyanurate muaj qhov zoo tshaj plaws thermal stability. Nyob rau hauv kev tsim cov elastomers, ortocyanates ntau dhau mus ntxiv nrog cov qauv aminoformate thiab urea los tsim kho thiab biuret hla kev sib txuas qauv. Txawm hais tias lawv tuaj yeem txhim kho cov khoom siv tshuab ntawm elastomers, lawv muaj qhov tsis ruaj khov rau tshav kub.
Txhawm rau txo cov pab pawg ua kom muaj zog xws li biuret thiab urea tsim hauv Elastomers, nws yog qhov tsim nyog los txiav txim siab lawv cov khoom siv raw thiab ntau lawm cov txheej txheem. Kev siv hluav taws xob ntau dhau yuav tsum siv, thiab lwm txoj hauv kev yuav tsum tau siv ntau li ntau tau ua ntej (polyols), thiab tom qab ntawd qhia lawv mus rau hauv Elastomer raws li cov txheej txheem ib txwm muaj. Qhov no tau dhau los ua txoj kev siv ntau tshaj plaws rau kev tsim cov kev ua kom sov-resistant thiab nplaim taws tiv thaiv polyurethane elastomers.
03 hydrolysis thiab cua sov oxidation
Polyurethane elastomers yog nquag rau thermal decomposition nyob rau hauv lawv ntu ntu thiab coj cov tshuaj sib hloov hauv lawv cov chaw mos ntawm cov chaw kub. Polyester elastomers muaj cov dej tsis zoo thiab ntau dua ntau dua rau hydrolyze ntawm cov kub. Qhov kev pabcuam lub neej ntawm polyester / tdi / lub hlis tuaj yeem ncav cuag 4-5 hlis ntawm 50 ℃, tsuas yog ob lub lim tiam ntawm 70 ℃, thiab tsuas yog ob peb hnub saum 100 ℃. Ester Bondpose tuaj yeem decomepose rau hauv cov acids sib xws thiab siv cov pab pawg kub thiab cov pab pawg urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea thiab urea es
Xov Tooj H20- → Rcooh Hor
Ester Cawv
Ib rnhohr ib h20- → rxhcooh H2NR -
Kev yaum
Ib rnhof-h20- → rncooh hor -
Amino tsim ester amino daim ntawv cawv
Polyether Raws Li Elastomers muaj kev txom nyem thermal oxidation stability α- hydrogen ntawm cov pa roj hmab atom yog yooj yim oxidized, sib sau ua cov dej hydrogen peroxide. Tom qab cov kev tsis sib haum xeeb thiab kev txuag, nws generates radicals thiab hydroxyl radicals, uas thaum kawg decompose rau hauv tsim los yog aldehydes.
Cov polyesters sib txawv muaj cov nyhuv me me ntawm cov cua sov tsis kam ntawm elastomers, thaum cov polyethers muaj qee yam cuam tshuam. Piv nrog TDI-MOCA-PTMEG, TDI-PTMA-PTMEG muaj lub zog khaws nyiaj ntawm 44% thiab 60 xyoo, nrog tom kawg tau ua kom zoo dua li qub. Qhov laj thawj yuav yog PPG lwg me me muaj cov ceg sib txuas, uas tsis muaj txiaj ntsig zoo rau cov kev ua haujlwm ywj siab ntawm lub tshuab hluav taws xob tsis tu ncua. Lub thermal stability txiav txim siab ntawm polyether yog: ptmeg> pepg.
Lwm cov pab pawg ua haujlwm hauv polyurethane elastomers, xws li urea thiab carbamate, kuj yauv tawm oxidation thiab hydrolysis kev tawm tsam. Txawm li cas los xij, cov pab pawg ether yog qhov yooj yim tshaj oxidized, thaum tus txhawb pab txhawb nqa yog qhov yooj yim tshaj hydolyzed. Qhov kev txiav txim ntawm lawv cov antioxidant thiab hydrolysis tsis kam yog:
Antioxidant kev ua: Esters> urea> carbamate> ether;
Hydrolysis Kuj: Eser
Txhawm rau txhim kho cov oxidation tsis kam ntawm polyety, ntxiv yog ntxiv, xws li ntxiv 1% antioxidant irganox1010 rau ptmeg polyether elastomer. Lub zog tensile ntawm no Elastomer tuaj yeem nce los ntawm 3-5 zaug piv rau yam tsis muaj antioxidants (kuaj cov txiaj ntsig tom qab kev laus ntawm 1500c rau 168 teev). Tab sis tsis yog txhua antioxidant muaj qhov cuam tshuam ntawm polyurethane elastomers, tsuas yog qhov zoo tshaj plaws, thiab cov antolic 110) Txawm li cas los xij, vim yog cov pab pawg tseem ceeb ntawm cov pab pawg ntawm cov tshuaj tiv thaiv kab mob pheb Yog tias ntxiv thaum lub sij hawm ntau lawm cov prepolymers, nws yuav cuam tshuam zoo heev rau cov nyhuv ua kom ruaj khov.
Cov tshuaj sib ntxiv siv los tiv thaiv hydrolysis ntawm polyester polyurethanes elasteane elasthanes tsim los ntawm polbodiimide compastomer molecules los tsim cov acyl urea derivatives, tiv thaiv kev tiv thaiv ntau hydrolysis. Qhov sib ntxiv ntawm carbodiimide ntawm pawg pawg ntawm 2% mus rau 5% tuaj yeem nce cov dej ruaj khov ntawm polyurethane los ntawm 2-4 zaug. Tsis tas li ntawd, tertyl categhol, hexamethylenetregine, azodicarbonamide, thiab lwm yam kuj muaj qee yam anti hydrolyly los.
04 Lub Ntsiab Kev Ua Haujlwm Zoo
Polyurethane elastomers yog cov ntau thaiv cov copolymers, nrog cov kab hlau sib txuas nrog cov chav ntsuas kub uas muaj qhov kub thiab txias dua li chav kawm kub siab dua li chav tsev. Ntawm lawv, oligomeric polyols daim ntawv sau cov ntu, thaum lub sij hawm Diisocyanates thiab Molecule Molecuel Chain Extenders. Tus qauv teeb tsa ntawm cov ntu daws teeb meem thiab cov ntu sib tw txiav txim siab lawv cov kev ua tau zoo tshwj xeeb:
(1) Cov roj hmab nyuaj ntawm cov roj hmab zoo ib txwm muaj nyob ntawm shoeer a20-A90, thaum lub hardness ntau ntawm cov yas yog hais txog cov yas yog hais txog saoer 95 shaoer d100. Polyurethane elastomers tuaj yeem ncav cuag li shaoer A10 thiab siab npaum li Shaoer D85, tsis tas yuav muaj kev pab lim;
(2) lub zog siab thiab elasticity tseem tuaj yeem tswj tsis pub dhau ntau yam ntawm kev tawv;
(3) hnav zoo tshaj plaws tiv thaiv, 2-10 zaug uas muaj roj hmab ntuj;
(4) Zoo heev tiv taus dej, roj, thiab tshuaj lom neeg;
(5) Kev cuam tshuam siab kuj, nkees ua hauj lwm, thiab kev co ua kom tau, haum rau kev siv cov ntawv siv puas yog cov khoom lag luam;
(6) Qhov qis qis-kub tsis kam, nrog tsawg-kub brittleness hauv qab -30 ℃ lossis -70 ℃;
(7) Nws muaj kev ua haujlwm rwb rwb rwb rwb thaiv tsev, thiab vim nws cov thermal tsawg thermal, nws muaj cov txiaj ntsig zoo dua piv rau roj hmab thiab yas;
(8) biocompatibility thiab anticoagulant tej yam;
(9) rwb thaiv tsev hluav taws xob zoo heev, pwm tiv thaiv, thiab UV ruaj khov.
Polyurethane elastomers tuaj yeem tsim cov txheej txheem qub xws li roj hmab zoo tib yam, xws li yas roj hmab, sib tov, thiab vulcanization. Lawv kuj tseem tuaj yeem tuaj yeem moulded nyob rau hauv daim ntawv ntawm kua roj hmab los ntawm pouring, centrifugal moulding, lossis txau. Lawv kuj tuaj yeem ua rau hauv cov ntaub ntawv granular thiab tsim kev txhaj tshuaj, extrusion, tshuab moulding, thiab lwm yam txheej txheem. Nyob rau hauv txoj kev no, tsis tsuas yog ua nws txoj haujlwm ua haujlwm, tab sis nws tseem txhim kho qhov tseeb qhov tseeb thiab cov tsos ntawm cov khoom
Lub Sijhawm Post: Dec-05-2023