Polyurethane yog cov khoom siv polymer feem ntau yog polymerized los ntawm diisocyanate, saw extender, thiab oligomer polyol ua cov khoom siv raw. Nws muaj cov khoom zoo ntawm cov roj hmab thiab yas. Nws muaj cov khoom siv zoo heev, hnav tsis kam, roj ua haujlwm, tsim kua muag, tshuaj tiv thaiv corrosion, hluav taws xob tiv thaiv, adhesion zoo thiab lwm yam khoom zoo, tab sis nws qhov kub thiab txias feem ntau tsis tshaj 80 degree, thiab cov ntaub ntawv siab tshaj 100 degree yuav soften thiab deform, mechanical Qhov kev ua tau zoo yog qhov tsis muaj zog, thiab siv lub sijhawm luv luv kub tsis tshaj 120 degree, uas txwv tsis pub nws daim ntawv thov nyob rau hauv qhov kub thiab txias.
Niaj hnub no, Xiaobian tau tshuaj xyuas cov xwm txheej cuam tshuam rau cov cua kub tsis kam ntawm elastomers los ntawm cov yam ntxwv ntawm oligomer polyols, isocyanates, saw extenders, catalysts, polymerization txheej txheem, kev taw qhia ntawm intramolecular pawg, ntxiv cov fillers, thiab cov khoom sib xyaw nrog nanomaterials.
1. Kev cuam tshuam ntawm cov ntaub ntawv raw ntawm cov cua sov ua haujlwm ntawm polyurethane elastomers
Polyurethane elastomer muaj qhov muag muag (oligomer polyol, feem ntau muab faib ua polyester hom, polyether hom thiab polyolefin hom polyol, thiab lwm yam) thiab ntu nyuaj (diisocyanate thiab saw extender). Tus txheeb ze molecular hnyav ntawm oligomer polyols yog polydispersed, thaum polyisocyanates feem ntau yog sib xyaw ntawm ntau yam isomers. Lub hav zoov ntawm isomers yuav rhuav tshem qhov tsis tu ncua ntawm cov ntu nyuaj thiab txo qhov kub tsis kam ntawm elastomers. nruj me ntsis tswj cov purity ntawm raw cov ntaub ntawv thiab txo cov molar feem ntawm cov pab pawg uas tsis zoo thermal stability xws li biuret thiab allophanate tuaj yeem txhim kho cov cua sov ntawm elastomers.
A. Oligomer polyol
Lub thermal decomposition kub ntawm urethanes tsim los ntawm cov tshuaj tiv thaiv ntawm oligomeric polyols nrog cov qauv sib txawv thiab tib isocyanate sib txawv heev, thawj cawv yog qhov siab tshaj, thiab tertiary cawv yog qis tshaj. Qhov no yog vim tias cov ntawv cog lus ze rau tertiary thiab quaternary carbon atoms yog qhov yooj yim tshaj plaws. vim kev tawg. Txij li thaum lub thermal stability ntawm ester pawg kuj zoo, thiab cov hydrogen ntawm cov pa roj carbon atom ntawm ether pawg yog yooj yim oxidized, lub tshav kub tsis kam ntawm polyester polyurethane yog zoo dua li ntawm polyether polyurethane. Polyurethanes ua los ntawm polyesters muaj me ntsis cuam tshuam rau thermal zog nyob ntawm seb hom polyester.
Rau polyether polyurethane, hom polyether muaj qee yam cuam tshuam rau nws cov cua sov, xws li toluene diisocyanate (TDI), 3,3'-dichloro-4, 4'-diphenylmethanediamine (MOCA) thiab polyurethane npaj los ntawm polyoxypropylene diol thiab polytetrahydrofuran ether diol (PTMG), feem, tom qab hnub nyoog ntawm 121 degree C rau 7 hnub, muaj qhov sib txawv tseem ceeb ntawm lub zog tensile ntawm ob. Lub zog tensile tuav tus nqi ntawm lub qub yog nyob rau hauv chav tsev kub. 44 feem pua, thaum tom kawg muaj tus nqi khaws cia ntawm 60 feem pua. Cov txheeb ze molecular loj los yog molecular saw ntev ntawm oligomer polyols tsis muaj kev cuam tshuam rau tus yam ntxwv decomposition kub ntawm thermal degradation ntawm polyurethane. Liu Liangbing tau kawm txog cov txheej txheem degradation ntawm polyester thiab polyether polyurethane, thiab tshuaj xyuas qhov cuam tshuam rau nws cov thermal kuj. , nws tau xaus lus tias qhov kub tsis kam ntawm polyester polyurethane elastomer zoo dua li ntawm polyether hom.
B. Isocyanates
Cov ntu nyuaj yog qhov tseem ceeb ntawm cov txheej txheem uas cuam tshuam rau lub tshav kub tsis kam ntawm polyurethane elastomers. Qhov zoo dua qhov rigidity, tsis tu ncua thiab symmetry ntawm cov ntu nyuaj, qhov siab dua thermal stability ntawm elastomer. Qhov loj feem ntawm cov ntu nyuaj nce, tsim ntau cov qauv txiav txim thiab cov qauv subcrystalline ntawm cov ntu nyuaj, yog li ntawd ob theem yog thim rov qab, ntu ntu ntu yuav dhau los ua ntu ntu, thiab ntu ntu ntu yog tawg mus rau theem nyuaj, yog li txhim kho lub zog tensile ntawm lub elastomer ntawm qhov kub thiab txias zog. Hais txog cov qauv molecular, diphenylmethane diisocyanate (MDl) zoo ib yam li TDI hauv cov qauv molecular, ob qho tib si muaj NCO pab pawg thiab benzene nplhaib qauv, tab sis vim nws cov qauv yooj yim, nruj, tsis tu ncua thiab symmetry, nws elastomer tsis muaj zog. Qhov degree ntawm microphase sib cais tsis txaus, thiab qhov thermal stability ntawm cov elastomers tau txais yog qhov nruab nrab. Feem ntau, qhov siab dua qhov purity ntawm isocyanate, qhov isomers tsawg dua, qhov siab dua qhov qub thiab sib luag ntawm qhov tshwm sim polyurethane elastomer, thiab qhov zoo dua cov cua sov. Cov ntu nyuaj tsim los ntawm isocyanates nrog cov qauv tsis tu ncua yog yooj yim rau kev sib sau, uas txhim kho qib ntawm microphase sib cais. Cov pawg polar nruab nrab ntawm cov ntu nyuaj tsim cov ntawv cog lus hydrogen los tsim cov cheeb tsam crystalline ntawm cov theem nyuaj, kom tag nrho cov qauv muaj cov ntsiab lus melting ntau dua.
Piv txwv li, 1,5-naphthalene diisocyanate (NDl) muaj cov qauv ntawm naphthalene nplhaib thiab muaj cov saw hlau molecular, thiab cov khoom sib txuas elastomer muaj cov khoom zoo heev. Zhen Jianjun et al. synthesized polyurethane elastomers nrog NDI thiab TDI thiab polyethylene adipate diol (PEPA), feem, thiab pom tias thermal decomposition kub ntawm NDI-hom polyurethane elastomers yog siab dua li ntawm TDI-hom polyurethane elastomers los ntawm thermogravimetric tsom xam. Tsis tas li ntawd, kev sib piv ntawm qhov kub thiab txias tuav tus nqi ntawm txhua yam khoom ntawm elastomers ntawm qhov sib txawv ntawm qhov kub thiab txias qhia tau hais tias qhov kub tsis kam ntawm NDI-hom polyurethane elastomers zoo dua li ntawm TDI-hom polyurethane elastomers.
PPDI-hom elastomer npaj los ntawm p-phenylene diisocyanate (PPD1) muaj ob peb lub sij hawm ua kom sov zoo dua li MDI thiab TDI-hom elastomers vim qhov tsis tu ncua ntawm cov qauv ntawm PPDI. Thiab 1, 4-cyclohexanediisocyanate (CHDl) kuj yog vim nws cov qauv molecular yooj yim, siab symmetry thiab tsis tu ncua, muaj zog crystallinity, thiab qhov tshwm sim elastomer muaj qib zoo ntawm theem sib cais. Li Fen, thiab lwm yam. piv rau lub cev tseem ceeb ntawm CHDI-hom polyurethane elastomer nrog MDI, PPDI, methylene dicyclohexyl-4,4',-diisocyanate (HMD1). Cov txiaj ntsig tau pom tias CHDI-hom polyurethane elastomer muaj zog dua ntawm cov ntsiab lus nyuaj ntu, thiab muaj cov khoom siv hluav taws xob zoo dua li MDI-hom, HMDI-hom thiab txawm tias PPDI-hom elastomers.
Tsis tas li ntawd, ntxiv cov trimerization catalyst lossis post-vulcanization nyob rau hauv qhov chaw ntawm ntau tshaj isocyanate tuaj yeem tsim cov isocyanate crosslinks ruaj khov hauv elastomer, yog li txhim kho cov cua sov ntawm elastomer.
C. Catalyst
Alicyclic isocyanates muaj qhov tsis tshua muaj tshwm sim, thiab cov catalyst yuav tsum tau ntxiv rau cov tshuaj tiv thaiv kab mob los txhawb cov tshuaj tiv thaiv mus rau qhov xav tau thiab ceev. Cov catalysts siv tau tshaj plaws yog organometallic compounds. Polymeric organic carboxylic acids thiab tertiary amine compounds kuj muaj lub luag haujlwm zoo heev los txhawb cov tshuaj tiv thaiv ntawm isocyanates.
Zhang Xiaohua, et al. synthesized pob tshab polyurethane elastomers nrog PTMG, isophorone diisocyanate (1PDl), 1, 4-butanediol (BDO) thiab txawv catalysts xws li stannous isooctoate, dibutyltin dilaurate thiab cocatalyst K. Cov nyhuv ntawm catalyst hom ntawm cov khoom siv kho qhov muag, , qib ntawm cov tshuaj tiv thaiv thiab thermal stability ntawm elastomer tau tshawb xyuas. Cov txiaj ntsig tau pom tias cov khoom sib xyaw catalyst stannous isooctanoate thiab nws cov co-catalyst K tau siv, vim tias cov co-catalyst K tuaj yeem nqus tau cov CO2 tso tawm los ntawm cov tshuaj tiv thaiv ntawm NCO pawg nrog dej thiab yog qhov tsim nyog rau kev tsim cov kab sib txuas sib txuas, yog li cov npaj polyurethane elastomer muaj kev ua haujlwm zoo. Mechanical zog thiab zoo heev thermal stability.
D. Cross-linking agent
Cov khoom zoo heev ntawm polyurethane elastomers yog ze ze rau lawv lub cev crosslinking thiab chemical crosslinking qauv. Kev sib txuas ntawm lub cev yog hais txog kev sib txuas ntawm hydrogen ntawm cov ntu tawv thiab nruab nrab ntawm cov ntu tawv thiab mos; chemical cross-linking yog hais txog covalent cross-linking bonds ntawm molecules tsim los ntawm tus neeg sawv cev sib txuas.
Lub cim ntawm kev sib txuas ntawm tshuaj lom neeg cuam tshuam kev txav mus los ntawm cov ntu mos. Nyob rau hauv txoj kev no, txoj kev ywj pheej spatial ntawm lub lattice lattice yog txo, uas tsis yog qhov tsim nyog rau lub crystallization ntawm cov mos mos ntu, thiab tiv thaiv cov ntu tawv los ntawm kev txav mus ze rau ib leeg. Qhov degree ntawm microphase sib cais yog txo. Zhang Xiaohua, et al. siv ib txoj hauv kev los ua kom cov pob tshab polyurethane elastomer nrog isophorone diisocyanate, polyoxytetramethylene glycol, 1, 4-butanediol thiab polyoxypropylene triol (N3010) ua raw khoom. Cov teebmeem ntawm lub cev thiab tshuaj lom neeg sib txuas ntawm cov khoom siv kho qhov muag, qhov pom kev pom tseeb thiab thermal stability ntawm polyurethane elastomers tau kawm los ntawm FT-IR, TG thiab lwm txoj kev. Cov txiaj ntsig tau pom tias qhov sib ntxiv ntawm tus neeg sawv cev sib txuas triol N3010, polyurethane elastomer ua cov ntawv sib txuas ntawm cov ntu nyuaj, thiab lub teeb xa hluav taws xob, thermal stability thiab cov khoom siv kho tshuab tau zoo dua qub piv nrog cov polyurethane elastomer yam tsis muaj tus neeg sawv cev sib txuas. .
E. Chain Extender
Cov nyhuv ntawm cov saw extenders ntawm tshav kub kuj muaj feem xyuam rau nws rigidity. Feem ntau, qhov siab dua cov ntsiab lus ntu ntu, qhov zoo dua qhov kub tsis kam ntawm elastomer. Huang Zhixiong, thiab lwm yam. siv 4,4'-diphenylmethane-5-maleimide thiab 3,3'-dichloro-4,4'-diphenylmethanediamine (BMI-MOCA) saw extender kom tsis txhob muaj kev ua haujlwm siab ntawm MOCA muab Cov xwm txheej zoo rau kev ua cov khoom lag luam loj, thiab nws kuj yog ib qho yooj yim los ua ke polyurethane elastomers nrog siab hardness. Vim qhov kev taw qhia ntawm BMI aromatic nplhaib qauv, tus txheeb ze nce ntawm ntu ntu tuaj yeem txhim kho thermal stability ntawm polyurethane elastomer.
Tsis tas li ntawd, cov saw extender hydroquinone bishydroxyethyl ether (HQEE) yog ib hom tshiab ntawm cov saw hlau txuas ntxiv, uas tuaj yeem hloov MOCA. Nws muaj ntau yam zoo thiab yog siv dav hauv polyurethane elastomers, uas tuaj yeem txhim kho cov cua sov thiab tsim kua muag ntawm polyurethane. tawg lub zog thiab compound cia stability.
2. Cov nyhuv ntawm cov txheej txheem polymerization ntawm lub tshav kub tsis kam ntawm elastomers
Lub thermal stability ntawm urea pawg thiab urethane pawg yog ntau dua li ntawm allophanate thiab biuret, uas qhia tau hais tias nce mole feem ntawm urea pawg thiab urethane pawg nyob rau hauv lub elastomer molecule txo allophanate cov mole feem ntawm ester pawg thiab biuret pab pawg neeg tuaj yeem txhim kho cov thermal. kev ruaj ntseg ntawm elastomer, uas yog, nruj me ntsis tswj cov txheej txheem, tshwj xeeb tshaj yog tus nqi thiab purity ntawm cov reactants, thiaj li hais tias cov tshuaj tiv thaiv muaj peev xwm tsim ntau urea pawg thiab carbamates li sai tau. Nws yog ib qho tseem ceeb heev los txhim kho qhov kub tsis kam ntawm elastomers. Lub tshav kub tsis kam ntawm polyurethane elastomers tuaj yeem txhim kho tau zoo los ntawm kev siv diamine chain extension vulcanization los tsim urea pawg, tswj cov tshuaj tiv thaiv ntawm NCO pawg thiab urea pawg los tsim cov biurets, thiab siv cov tshuaj tsw qab diisocyanates. Cov tshuaj tiv thaiv ntawm polyurethane feem ntau muaj xws li ib-kauj ruam txoj kev, prepolymerization txoj kev thiab semi-prepolymerization txoj kev. Cov txheej txheem ib-kauj ruam yog qhov yooj yim, tab sis cov qauv molecular ntawm cov khoom feem ntau tsis sib xws thiab kev ua haujlwm tsis zoo. Txoj kev prepolymerization thiab semi-prepolymerization txoj kev zoo dua.
Lub German patent qhia tias ib tug semi-prepolymerization txoj kev yog siv kom tau ib tug polyurethane elastomer nrog ib tug softening kub ntawm 147 degree. Tsis tas li ntawd, tom qab-vulcanization tej yam kev mob ntawm ntau tshaj 4 teev ntawm qhov kub ntawm txog 120 ° C kuj tuaj yeem txhim kho cov cua sov ua haujlwm deformation ntawm polyurethane elastomer casting compound.
3. Qhov cuam tshuam ntawm kev hloov kho ntawm kev kub nyhiab ntawm polyurethane elastomer
A. Cov nyhuv ntawm kev hloov kho silicone ntawm cov cua sov ntawm elastomers
Silicone muaj ib tug tshwj xeeb qauv thiab zoo heev kub thiab tsis kub tsis kam thiab oxidation kuj, zoo heev hluav taws xob rwb thaiv tsev thiab thermal stability, zoo heev huab cua permeability thiab biocompatibility, thiab lwm yam. Thaum tshav kub kub kuj, nws kub distortion kub yuav ncav cuag 190 degree.
Yog vim li cas rau nws cov cua kub tsis zoo yog tias ntawm ib sab, qhov thermal stability ntawm SiO2 daim ntawv cog lus yog qhov zoo, thiab ntawm qhov tod tes, cov ntu mos nrog siloxane raws li lub cev tseem ceeb muaj qhov hloov tau zoo, uas muaj txiaj ntsig zoo rau kev sib cais microphase. Stanciu A et al. npaj cross-linked polyols nrog poly-L-alcohol adipate diol (PEGA), hydroxyl-terminated polydimethylsiloxane (PDMS-OH), MDI, thiab diglyceride maleate polyols. Polyester-polysiloxane-polyurethane elastomer, kev ntsuas kev ua tau zoo qhia tau hais tias PDMS-OH muaj kev cuam tshuam me ntsis ntawm cov khoom siv ntawm cov khoom kawg, tab sis tau txhim kho kev ruaj ntseg thiab elasticity ntawm qhov kub thiab txias, thiab zoo dua thermal stability.
Wen Sheng, et al. synthesized ib series ntawm siloxane-muaj polyurethane elastomers siv polydimethylsiloxane (PDMS) nrog ib pawg hydroxyl kawg thiab polytetrahydrofuran ether diol li cov khoom sib xyaw. Thermogravimetric tsom xam (TGA) qhia tau hais tias, kev taw qhia ntawm PDMS txhim kho thermal stability ntawm tsoos polyurethane elastomers.
B. Kev cuam tshuam ntawm kev taw qhia ntawm intramolecular pawg ntawm cov cua sov ua haujlwm ntawm elastomers
Lub thermal decomposition kub ntawm polyurethane elastomer tsuas yog nyob ntawm qhov kub tsis kam ntawm ntau pawg hauv cov qauv macromolecular. Yog hais tias muaj ob daim ntawv cog lus nyob rau hauv cov mos mos, nws yuav txo qhov kub tsis kam ntawm lub elastomer, thaum lub sij hawm kev taw qhia ntawm isocyanurate rings thiab inorganic cov ntsiab lus tuaj yeem txhim kho lub tshav kub tsis kam ntawm polyurethane elastomer. Kev taw qhia ntawm lub thermally ruaj khov heterocycle (xws li lub nplhaib isocyanurate, lub nplhaib polyimide, lub nplhaib oxazolidinone, thiab lwm yam) rau hauv cov saw tseem ceeb ntawm PU molecule tuaj yeem txhim kho qhov kub tsis kam ntawm polyurethane elastomer.
Lub trimer ntawm aliphatic lossis aromatic polyisocyanate muaj ib lub nplhaib isocyanurate, uas muaj cov cua sov ua haujlwm zoo thiab qhov ruaj khov, thiab nws cov khoom siv tau ntev ntawm 150 degree. Cov polyimide ua los ntawm cov tshuaj tiv thaiv ntawm dicarboxylic anhydride thiab diisocyanate muaj cov yam ntxwv ntawm insolubility thiab kub tsis kam. Kev taw qhia ntawm lub nplhaib polyimide rau hauv PU tuaj yeem txhim kho cov cua sov thiab kev ruaj ntseg ntawm polyurethane elastomer. Lub oxazolidinone compound tsim los ntawm cov tshuaj tiv thaiv ntawm epoxy pab pawg neeg thiab isocyanate nyob rau hauv lub xub ntiag ntawm ib tug catalyst muaj zoo thermal stability, thermal decomposition kub tshaj 300 degree, thiab lub iav hloov kub kub yog siab tshaj 150 degree, uas yog ho siab tshaj li ntawm zoo tib yam polyurethane. elastomers. .
C. Cov nyhuv ntawm compounding nrog nanoparticles thiab fillers ntawm lub tshav kub tsis kam ntawm elastomers
Nanomaterials yog "cov ntaub ntawv zoo tshaj plaws nyob rau hauv lub xyoo pua 21st", thiab cov polymer-raws li nanocomposites hais txog qhov loj ntawm cov theem dispersed nyob rau hauv tsawg kawg yog ib qhov ntev ntawm nanoscale ntau. Vim nws cov khoom tshwj xeeb, nanoparticles yog sib xyaw nrog polyurethane elastomers los txhim kho lawv cov khoom siv kho tshuab, thiab tuaj yeem ua rau cov khoom ua haujlwm ntawm elastomers xws li kub tsis kam thiab tiv thaiv kev laus. Kev sib xyaw ntawm nanoparticles thiab elastomer yog ib hom tshiab ntawm cov khoom siv sib xyaw tsim nyog ntawm kev tshawb fawb thiab kev tsim kho.
Gilman, JW, et al. pom los ntawm X-ray diffraction tshwm sim ntawm polyurethane-montmorillonite nanocomposites tias montmorillonite tau tawg nyob rau hauv lub polyurethane matrix nrog ib tug dav tis nrog ib tug nruab nrab interlayer spacing tsis tsawg tshaj li 415 nm, thiab cov silicate nyob rau hauv lub montmorillonite ua lub luag hauj lwm nyob rau hauv thermal rwb thaiv tsev. . Nws tuaj yeem txhim kho qhov kub tsis kam ntawm cov khoom sib xyaw. ZhuY et al. siv cov khoom zoo tshaj plaws ntawm polyurethane elastomers thiab inorganic hais-nano-SiO2 los npaj SiO2 polyurethane elastomer nanocomposites los ntawm sol-gel txoj kev. Cov txiaj ntsig kev sim qhia tau hais tias qhov sib ntxiv ntawm nano-SiO2 tuaj yeem txhim kho cov khoom siv kho tshuab ntawm polyurethane elastomer matrix, thiab kuj muaj qee yam kev txhim kho hauv nws cov cua sov.
Cov khoom ntim xws li calcium carbonate, carbon dub, quartz pob zeb, carbon fiber, iav fiber ntau, nylon, thiab kho cov khoom siv kuj tuaj yeem txhim kho thermal deformation tsis kam ntawm polyurethane elastomers. Du Hui, et al. tau kawm txog cov teebmeem ntawm cov khoom sib txawv inorganic ntawm cov khoom siv kho tshuab thiab cov cua sov ua haujlwm ntawm polyurethane elastomers. Cov txiaj ntsig tau pom tias cov khoom siv hluav taws xob thiab cov cua sov ua haujlwm ntawm polyurethane elastomers hloov nrog micron-scale inorganic fillers yog qhov zoo dua li cov polyurethane elastomers zoo tib yam. .
4, Daim ntawv thov tsim qauv
Muaj ntau txoj hauv kev los txhim kho cov thermal deformation ntawm polyurethane elastomers. Hauv kev siv tswv yim, kev xaiv tsim nyog yuav tsum tau ua raws li cov khoom ntsuas kev ua tau zoo thiab cov txheej txheem yuav tsum tau ua, thiab cov txheej txheem ua tau yuav tsum tau txiav txim siab. Txawm hais tias kev txhim kho tshav kub tsis kam ntawm polyurethane elastomers yeej ib txwm yog lub ntsiab lus tseem ceeb hauv kev ua haujlwm ntawm polyurethane elastomers, thiab ntau txoj kev tshawb fawb tau ua tiav, tseem muaj ob peb polyurethane elastomers uas muaj cov khoom zoo heev xws li kub tsis kam thiab cov khoom siv tshuab, thiab tag nrho cov theem tseem qis. nyob rau hauv lub laboratory txoj kev loj hlob theem. Tsim cov kev hloov kho tshiab thiab ntxiv dag zog rau kev lag luam ntawm cov txiaj ntsig tseem yog cov ntsiab lus tshawb fawb tseem ceeb hauv thaj chaw polyurethane yav tom ntej.
Kev ua haujlwm kub zoo, PPDI, NDI, TODI thiab CHDI, yog tias koj xav ua prepolymer, NDI kev ua haujlwm siab dhau lawm, uas tsis yog qhov tseeb tam sim no (nws tau hais tias Prepolymer Research Institute ntawm Burley Bayer tau ua tiav cov khoom zoo. cia ruaj khov NDI prepolymer), tus so yog ok. Feem ntau hais lus, rau cov uas xav tau thermal stability thiab yellowing, CHDI yog zoo dua, thiab PPDI uas yuav tsum tau tshav kub tsis kam thiab dynamic mechanical zog yog zoo dua. Yog tias TODI txuas ntxiv nrog amines, qhov kev ua tau zoo nyob ze rau NDI.
