Daim Ntawv Nco Corrosion-Resistant Polymeric Cov Khoom Siv Ntu 2

Polymers ua haujlwm los ntawm qhov muaj peev xwm sib cuam tshuam ntawm cov thermosets thiab cov thermoplastics, qhov twg cov thermosets tau txhais los ntawm lawv cov tshuaj crosslinks uas ua rau peb-dimensionalnetwork uas tuaj yeem txuas mus rau qhov ntev ntev thiab cov thermoplastics tsis muaj cov tshuaj sib txuas sib txuas thiab tsuas muaj qhov ntev ntev.

Chemical cross-linking hais txog kev ntxiv cov tshuaj reactive rau cov ntaub ntawv kom lawv hnov ​​​​mob hauv cov xwm txheej tshwj xeeb los tsim cov gel lossis cov khoom tawv. Txoj kev no yog siv dav hauv cov txheej txheem kev npaj ntawm ntau yam ntaub ntawv, xws li cov ntaub ntawv fiber ntau, plastics, roj hmab, txheej, thiab lwm yam, thiab muaj kev thov dav dav.

Kev sib raug zoo nrog kev nco yog tias cov ntaub ntawv npaj los ntawm kev sib txuas ntawm cov tshuaj lom neeg muaj peev xwm nco tau. Cov khoom siv no tuaj yeem hloov pauv cov duab raws li kev txhawb nqa sab nraud thiab rov ua nws cov duab qub thaum khaws "nco" ntawm nws cov duab qub. Cov cuab yeej zoo li no tau muab cov khoom siv no ntau yam ntawm kev cia siab, xws li cov khoom siv ntse hauv kev kho mob, kev tsim kho, tsheb, thiab lwm yam.

Tsis tas li ntawd, chemical cross-linking thev naus laus zis kuj tuaj yeem siv los tswj thiab txhim kho cov khoom ntawm cov khoom, muab lawv lub cev zoo thiab tshuaj lom neeg thiab thermal stability. Cov thev naus laus zis no muaj peev xwm txhim kho siab thiab tuaj yeem siv rau kev npaj thiab hloov kho cov ntaub ntawv organic thiab inorganic, ua lub luag haujlwm tseem ceeb hauv kev txhim kho kev txhim kho ntawm cov khoom siv engineering.

Yog li ntawd, chemical cross-linking technology yog ib qho kev cog lus zoo heev nrog ntau qhov zoo thiab daim ntawv thov tus nqi. Nws daim ntawv thov muaj kev cia siab dav dav hauv ntau qhov chaw thiab tau pab txhawb rau kev txhim kho engineering technology thiab kev vam meej hauv zej zog. Nws tuaj yeem pom tias peb yuav tsum txhim kho kev nco, thiab Cistanche deserticola tuaj yeem txhim kho kev nco, vim Cistanche deserticola muaj antioxidant, tiv thaiv kev mob, thiab tiv thaiv kev laus, uas tuaj yeem pab txo qis oxidation thiab inflammatory tshwm sim hauv lub hlwb, yog li tiv thaiv cov kab mob. kev noj qab haus huv ntawm lub paj hlwb. Tsis tas li ntawd, Cistanche deserticola kuj tseem tuaj yeem txhawb kev loj hlob thiab kho cov paj hlwb, yog li txhim kho kev sib txuas thiab kev ua haujlwm ntawm neural networks. Cov teebmeem no tuaj yeem pab txhim kho kev nco, kev kawm muaj peev xwm, thiab kev xav nrawm, thiab tseem tuaj yeem tiv thaiv kev loj hlob ntawm kev paub tsis meej thiab cov kab mob neurodegenerative.

Nyem Paub txhawm rau txhim kho lub cim xeeb luv luv

Kev ua cov thermoplastics suav nrog kev ua kom txias sai thiab ua kom khov cov nplaum polymer yaj. Thermoset processing yuav tsum muaj cov tshuaj tiv thaiv uas tsis tshua muaj viscosity precursors, thiab tus nqi ntawm kev ua yog txwv los ntawm tus nqi ntawm cov tshuaj tiv thaiv kinetics.

Nyob nruab nrab ntawm ob, cov thermosets yuav muaj ntau dua dimensionalstability thiab creep resistance, ua rau lawv nyiam forstructural composite daim ntaub ntawv tshaj thermoplastics [28].Los ntawm blending cov polymers, ib tug yuav customize, mus rau ib tug tej yam, cov khoom ntawm lub cim xeeb polymer, nrog lub hauv paus. polymer tsim cov duab cim xeeb thiab lwm cov polymers rau tag nrho cov cohesion thiab deformability (piv txwv li, tom qab elongation, lub crystallinity muab los ntawm lwm cov polymers tiv thaiv lub elastomer los ntawm relaxing rov qab mus rau hauv thawj lub xeev) [29].

Lwm qhov zoo rau cov polymers hauv lawv cov ntaub ntawv yog lawv lub peev xwm qis, muaj hluav taws xob nrog lawv li, thiab cov khoom siv dav hlau uas cov thaiv lawv yog tsim los ntawm [2, 30].

Polymer-based shape memory composites thiab coatings yuav tsum muaj kev txhawj xeeb nrog cov iav hloov pauv kub, los yog Tg, muab tias cov polymer yuav nyob rau hauv lub xeev aglassy ua ntej lub ntsiab lus no thiab yog li yuav cuam tshuam rau lub shapemory yam ntxwv ntawm hais composite; countering no yuav xav kom cov khoom muab tub lim muaj peev xwm ntawm inhibiting cov thermomechanical teebmeem uas cov polymer nthuav tawm; Cov teebmeem ntawm cov thermomechanical feem ntau yog pom los ntawm kev sib txhuam kev sib txhuam uas tiv thaiv kev thauj khoom sab nraud [21]. Rau shapememory polymers, qhov no feem ntau yog nyob ntawm lub iav hloov pauv kub, tseem hu ua Tg, qhov kev hloov pauv tshwm sim saum toj no Tg, qhov twg nws dhau los ua rubbery, thiab txoj hauj lwm teeb tsa thaum lub polymer txav hauv qab Tg asit tig mus rau hauv lub xeev iav [ 2].

Muab hais tias cov duab nco composites xav tau daim ntawv thov ntawm lub zog sab nraud kom rov qab mus rau lawv cov thawj daim ntawv, cov khoom sib xyaw thermal nqus thiab kev ua tau zoo yog qhov tsim nyog los xav txog, raws li, feem ntau, qhov muaj peev xwm ntau dua rau cov khoom sib xyaw kom nqus tau los yog cov khoom siv hluav taws xob ua rau lub sijhawm zoo dua qub thiab tsawg zog siv los ua pov thawj hais tias lub sij hawm teb [21].

Txawm li cas los xij, muaj qhov tsis zoo hauv kev siv cov duab cim xeeb polymers, vim tias kev ua haujlwm yuav ploj mus dhau sijhawm; Yog li, ib txoj hauv kev los tiv thaiv cov txiaj ntsig zoo li no yog qhov tseem ceeb hauv kev nthuav tawm cov duab memorypolymer lub neej thiab nws lub peev xwm los tiv thaiv ib puag ncig.

4. Puab Memory Composites: Polymers thiab Polymer Blends

Ib txwm siv cov polymers tsis zoo rau ib puag ncig, uas txhais tau hais tias kev ua haujlwm qeeb zuj zus thaum lub sijhawm [30], tshwj xeeb tshaj yog nyob rau hauv daim ntawv ntawm microcracks, qhov kev sib tw loj tshaj plaws uas cov polymers ntsib nyob rau hauv daim ntawv thov mus sij hawm ntev, raws li lawv txo lub neej ntawm cov khoom thiab Nws yog qhov nyuaj dua los kuaj xyuas lossis kho [31].

Yog li, cov polymers xav tau ib qho kev tswj hwm thiab kho lawv cov kev ua haujlwm, txawm tias siv qee qhov kev thov sab nraud lossis, zoo dua, los ntawm qhov zoo ntawm cov khoom siv los yog cov khoom siv polymer; hauv lwm lo lus, cov polymer yuav tsum muaj lub peev xwm los kho nws tus kheej.

Raws li cov polymer yog cov khoom siv cim xeeb, kev ntxhov siab uas tshwm sim los ntawm ntau yam kev cuam tshuam, xws li tshuaj lom neeg, tshuab, lossis thermal, tuaj yeem ua rau lub tshuab deformation hauv cov khoom thiab kuj tuaj yeem ua kom muaj kev kho mob rau lub cev puas tsuaj uas tau tsim tawm [32] .

Feem ntau, kev kho pob tawg tshwm sim vim yog thermaleffects thiab pib ntawm lossis siab dua Tg. Raws li xws li, kev loj hlobshave feem ntau tsom rau kev kho qhov zoo Tg rau qhov xav tau qhov kub thiab txias, uas feem ntau qis dua li cov polymer li qub Tg [31].

Kev ua kom nws tus kheej zoo rau cov polymers suav nrog ob txoj hauv kev sib txawv uas tso siab rau kev sib cuam tshuam tshuaj lom neeg kom ua tiav lub hom phiaj: oneis los ntawm supramolecular rog, thiab lwm yam yog bydynamic covalent bonds tsim nyob rau hauv lub polymer blend. Ua ntej, tab sis, yog lub ntsiab txhais los ntawm cov polymeradheres. mus rau saum npoo.

Lub interfacial adhesion ntawm lub polymer matrix thiab 2D muab tub lim yog ib qho tseem ceeb ntawm cov cuab yeej cuab tam thiab muaj peev xwm rov tsim tau cov kev xav tau.Strong interfacial bonding ntawm lub polymer matrix thiab 2D muab tub lim muab cov polymer txheej siab modulus thiab tensile zog, txhim kho hardness, thiab nce coatingresistance rau kua muag, qaug zog, thiab corrosion [17].

Yog li, kev tsim cov duab cim xeeb sib xyaw ntawm cov polymer thiab an alloy yuav tsum siv cov khoom sib txuas, xws li trimethoxysilylpropyl methacrylate, los tsim cov kev sib txuas ntawm cov txheej txheem organic thiab inorganic ntawm txheej, vim tias tsis muaj kev sib txuas ua rau muaj kev cuam tshuam tag nrho cov cuab yeej siv tshuab vim cov khoom siv organic. tsis ua raws li cov ntaub ntawv inorganic [33].

Ib qho kev xaiv zoo tshaj plaws rau kev tiv thaiv corrosion thiab kev pom zoo rau kev sib txuas cov neeg sawv cev suav nrog polysiloxanes. Polysiloxanes yog hydrophobic polymers uas muaj peev xwm txhim kho qhov kev tiv thaiv corrosion ntawm cov khoom siv polymer los ntawm kev txwv cov dej nkag mus rau cov hlau / hybrid polymer txheej interface [17].

Yam ntxwv los ntawm Si-O-Si pab pawg, uas muaj kev sib txuas ntawm 104 thiab 180 degrees txuas rau lub polymerchain, qhov ntau ntawm cov ntawv cog lus lub kaum sab xis cuam tshuam rau txoj hlua khi thiab txhim kho lub zog ntawm daim ntawv cog lus, tsim lub hauv paus rau qhov tseem ceeb ntawm kev ua haujlwm ntev thiab ua haujlwm kub. uas polysiloxanes muaj [34].

4.1. Polydimethylsiloxane. Ib qho ntawm feem ntau siv polysiloxanes yog polydimethylsiloxane, abbreviated rau PDMS.PDMS elastomers feem ntau yog tsim los ntawm crosslinking linear polymers uas tau entangled thiab muaj zog tshaj qhov pib nqi rau qhov ntom entanglements uas ua tau zoo li crosslinks [35]; tus qauv tuaj yeem pom hauv daim duab 5.

Ib txoj hauv kev uas PDMS tuaj yeem txhim kho rau kev siv yog txo qhov nruj ntawm PDMS elastomers uas yuav txo tau lub zog tsim nyog rau deformation. Qhov no yog qhov tseem ceeb rau kev txhim kho kev ua raws li cov khoom siv uas yuav nyuaj rau kev siv cov txheej txheem rau, thiab ua tiav qhov no yuav txhais tau tias qhov kev txo qis ntawm qhov sib txawv ntawm qhov sib txawv. Kev siv cov kuab tshuaj tuaj yeem ua tiav qhov kev txo qis, tab sis cov kuab tshuaj tuaj yeem tawm thiab ua rau muaj kev phom sij rau ib puag ncig. PDMS tsis tuaj yeem muaj ashear modulus qis dua 200 kPa.

Los ntawm kev tsim cov crosslinkingbottlebrush matrix as opposed to a linear polymer, nws muaj peev xwm inhibit entanglement tsim thiab tsim ib tug controllable elastic modulus uas muaj peev xwm nyob ntawm 1 mus rau 100kPa, qhov twg lub modulus sib raug linearly rau qhov ceev ntawm thecrosslinking chains.

Tsis tas li ntawd, muaj peev xwm tswj tau tus kheej ntawm qhov poob modulus; Nws txo cov nplaum, tuaj yeem yooj yim tsim, thiab tej zaum yuav txuas ntxiv tunedvia lub nraub qaum / sab saw / crosslinking saw piv rau ntxiv tailor cov khoom siv kho tshuab [35].4.2.

Polymethylhydrosiloxane. Ntawm cov polysiloxanes muaj, polymethylhydrosiloxane, los yog PMHS luv luv, yog ib qho kev xaiv ntawm siloxane raws li nws tsis yog-tshuaj lom, ruaj khov nyob rau hauv huab cua, resistant rau kub kub, thiab yuav siv tau raws li ib tug txo tus neeg sawv cev rau kev hloov ntawm carbonyls rau cawv [17, 33 ]; Cov qauv yuav pom nyob rau hauv daim duab 6. PMHS muaj qhov chaw qis zog thiab zoo innate hydrophobicity thiab, ua tsaug rau nws cov inorganic andorganic molecular qhov chaw, ua raws li ib tug zoo coupling agent ntawm polymers thiab hlau nto.

PMHS yog qhov muaj txiaj ntsig zoo vim tias cov kuab tshuaj noorganic tsim nyog los npaj cov txheej txheem, uas yog qhov tseem ceeb rau kev txwv tsis pub muaj cov organic tebchaw uas tuaj yeem suav tias muaj kev phom sij rau ib puag ncig. Txawm li cas los xij, kev siv PMHS los ua kev ntsuas kev tiv thaiv corrosion yog qhov tsawg. Qhov ua tau zoo ntawm qhov sib ntxiv ntawm PMHS tuaj yeem pom los ntawm kev sim ua los ntawm Sun et al. qhov twg PMHS tau ntxiv rau apolyaniline-epoxy txheej.

Qhov no ua tiav txo lub zog saum npoo ntawm txheej txheej, txhim kho lub wettability, thiab tsim me me protuberances ntawm qhov chaw, uas tso cai rau ib txheej ntawm huab cua los tsim thiab inhibit kev sib cuag los ntawm cov tshuaj corrosive thiab adsorption ntawm cov tshuaj corrosiveions, uas ua rau muaj kev nce hauv qhov ua tau zoo ntawm cov txheej rau 70 hnub, qhov txheej tsis muaj PMHS tsuas yog siv tau 34 hnub [20].4.3. Supramolecular Polymers.

Supramolecular daim ntawv cog lus-raws li nws tus kheej-kho cov khoom muaj cov khoom siv polymer uas txuas nrog tus cwj pwm zoo li daim nplaum, uas lawv tuaj yeem txuas thiab rov txuas dua, thiab nws yog qhov nplaum uas muab cov khoom siv zog; itis tseem ceeb kom nco ntsoov tias qhov no tsis yog los ntawm covalentbonds lossis chain entanglements.

Cov ntawv cog lus no cuam tshuam rau cov khoom sib xyaw polymer lub zog, viscosity, ntws, thiab kev txiav txim ntawm nws cov saw hlau polymer nyob rau hauv thiab yog li muaj kev sib raug zoo nrog tus cwj pwm zoo ntawm cov khoom pov thawj polymer. Thaum qhov kev puas tsuaj tau tshwm sim rau cov qauv, qhov cuam tshuam ntawm qhov puas tsuaj yuav tom qab ntawd tsis muaj kev cuam tshuam supramolecular daim ntawv cog lus uas tseem "nqa" thiab muaj peev xwm rov ua dua thiab rov kho dua los kaw qhov kev puas tsuaj thiab rov qab mus rau lub xeev tsis muaj kev puas tsuaj yav dhau los. Hauv kev siv cov ntawv cog lus supramolecular, qhov kev txhawj xeeb hauv nruab nrab yog lub sijhawm nws yuav siv sijhawm rau kev rov qab los, lub zog ntawm cov khoom, thiab cov khoom muaj peev xwm rov qab tau cov khoom tom qab kev puas tsuaj [32].

Ib co piv txwv ntawmpolymers siv nyob rau hauv ib tug blend uas tso siab rau supramolecularforces kom ua tiav nws tus kheej-kho yog raws li nram no.4.3.1. Epoxy Ester. Epoxy ester resins paub tias muaj cov khoom zoo tiv thaiv corrosion thiab adhesion rau saum npoo tab sis txwv tsis pub siv vim lawv cov tshuaj tsis zoo thiab tsis muaj zog txhua yam khoom; xws li, nws raug pom zoo kom txhim kho lawv los ntawm kev siv cov khoom sib xyaw lossis copolymerization nrog lwm cov polymers uas muaj peev xwm tiv taus cov kub kub xws li polyurea lossis polysiloxane [17, 33]; tus sawv cev ntawm cov qauv yuav pom nyob rau hauv daim duab 7.

Polyurea feem ntau yog siv rau laminates hauv tsev thiab kev lag luam tsheb, qhov twg nws tuaj yeem txhim kho qhov cuam tshuam thiab tawg tsis kam ntawm epoxy ester [17]. Epoxy esters kuj raug txwv los ntawm lawv cov rings reactive heev, uas inhibit processability rau polymer blends thiab yog li ua rau lawv kim dua los tsim.

Feem ntau, thaum reacting epoxy estersto tsim cov polymers, cov epoxy functional pawg tau qhib los ntawm esterification ntawm unsaturated fattyacids rau ces tsim alkyd-hloov epoxy esters, nrog cov khoom tswj los ntawm txhais tau tias xws li theem ntawm unsaturation los yog cov saw ntev.

Cov khoom tsim epoxy ester emulsion yog ces dehydrated los ntawm evaporation ntawm dej rau coalesceand tsim ib zaj duab xis, uas yog kho los ntawm autoxidation, los yog oxygen cov tshuaj tiv thaiv los ua ib tug dawb radical saw mechanism.

Cov txiaj ntsig ntawm cov khoom yog nyob ntawm cov roj saw ntev.Piv txwv li, cov roj chains ntev hauv epoxy esters txhais tau hais tias cov tshuaj tiv thaiv qis dua, lub sij hawm ziab qhuav ntev dua, thiab txhim kho muaj peev xwm nkag mus thiab kaw qhov chaw tsis zoo, cov roj chains luv luv yog tawv thiab nkig thiab muaj cov tshuaj zoo thiab dej tsis kam [36]

4.3.2. Polyimide.

Feem ntau, polyimides nyiam nyob rau hauv engineering daim ntaub ntawv raws li lawv muaj zoo heev mechanicalproperties, zoo thermal stability, ib tug siab iav hloov kub, thiab ib tug tsawg dielectric tas li [36]; ib tug sawv cev ntawm cov qauv yuav pom nyob rau hauv daim duab 8.

Feem ntau cov kev tshawb fawb uas tsom rau kev kho tus kheej cov polymers yog cov uas ua haujlwm qis lossis nruab nrab Tg, qhov siab Tg polymers, uas yuav tsim nyog rau tus kheej-deployable aerospace lossis dav hlau propulsionapplications, tsis zoo li kawm. Lub cim xeeb varitof polyimide yuav yog ib qho zoo li polymer, vim nws muaj peev xwm ntawm Tg siab, nrog rau qhov kub thiab txias ntawm 218 degree, thiab kho tus kheej (uas tshwm sim ntawm 243 degree) ntawm tus nqi ntawm cov khoom siv qis qis thiab qis Tg (235 degree) rau qhov tsis zoo ntawm tus kheej zoo dua li qhov tsis yog tus kheej kho tus kheej, tab sis qhov ntawd yuav zoo vim yog polystyrene, thiab lwm yam khoom siv yuav zoo dua [37].

Polyimides yog txhais los ntawm ib pawg neeg ua haujlwm nruj heterocyclicimide thiab tau sau tseg rau kev sib cuam tshuam ntawm lawv cov electron-nplua nuj nitrogen atom thiab lawv cov electron-deficient carbonyl pawg nyob rau hauv lub qaum ntawm polyimide [38].

Txawm li cas los xij, polyimides yuav raug txwv rau lawv siv vim tsis muaj dej noo thiab adhesion, uas tuaj yeem ua rau tsis ua haujlwm ntawm lub ntsej muag thiab txwv lawv mus rau cov txheej txheem ntau dua li piv rau lwm cov txheej txheej, nrog rau lawv lub zog siab thiab dielectric tas li [36, 38. ].Kev dhau los ntawm cov kev txwv no feem ntau txhais tau hais tias ntxig hydrophobic polymer blocks rau hauv pob txha ntawm polyimide los yog koom nrog nanoparticles rau hauv matrix li ameans ntawm kev txo cov diffusivity thiab txheeb ze permittivity ntawm thepolyimide txheej [38].

Xws li nanoparticles muaj qhov cuam tshuam ntawm kev ua kom lub zog saum npoo rau polyimide, uas nyob rau hauv lem txo nws cov adhesion, whereas lub inclusion ofpolymer blocks rau hauv lub caj dab tuaj yeem txo qhov decomposition kub thiab yog li qhov kev pab cuam kub thiab mechanical zog [38]. Durability cuam tshuam rau kev tuav pov hwm ntawm cov khoom thaiv kev tuav los ntawm cov txheej txheem polymer thiab yog, rau cov polymers, tswj los ntawm crystallinity hauv txheej.

Kev txo qis hauv lub zog saum npoo ntawm cov txheej txheej cuam tshuam nrog kev nce hauv txheej tsis kam [25]. Polysiloxanes tuaj yeem siv rau kev txhim kho lub zog dissipation, yooj, thiab nto adhesion, tab sis raws li kev lag luam tawm, lawv txo qhov kawg ntawm lub zog thiab Young's modulus; Yog li ntawd, mitigatingthe detractions feem ntau yuav tsum tau manipulation ntawm themolecular hnyav feem pua ​​ntawm polysiloxane.

Rau Young's modulus kom nyob ze rau ntawm cov dawb polyimide, qhov hnyav ntawm polysiloxane feem pua ​​yuav tsum nyob nruab nrab ntawm 10 thiab 20%; Nws yog ib qho tsim nyog yuav tsum nco ntsoov tias ductility tseem ceeb txhim kho rau cov copolymerif polysiloxane nyob rau hauv 10 mus rau 40 wt%. Zuag qhia tag nrho, txuas apolysiloxane rau hauv cov pob txha ntawm polyimide chainimproves tag nrho cov txheej txheem ntawm polymer, inhibits qhov nqus dej, ua rau cov polymer muaj peev xwm ntawm adhering rau ntau qhov chaw, txhim kho thermalstability, thiab txo qhov decomposition kub txog qhov nce ntawm qhov chaw. wt% ntawm polysiloxane nyob rau hauv lub polymer (qhov no zoo nkaus li muaj feem xyuam rau kev txo qis hauv polyimide). Qhov tsis zoo ntawm polyimide-polysiloxanechains tuaj yeem kov yeej los ntawm kev sib ntxiv ntawm lwm cov copolymer, zoo li polyphenyl silsesquioxane, uas yog ib qho kev pom zoo polymer uas tseem tuaj yeem txhim kho qhov kub thiab txias ntawm cov polymer sib xyaw.

Qhia cov estergroup rau lub pob txha imide ua rau cov txiaj ntsig ntawm kev ua kom muaj zog ntawm cov polymer tab sis txo cov iav hloov pauv kub, qhov chaw ua ke poly (ester-imide) moleculeh muaj iav hloov pauv kub ntawm 185 degree thiab kev tshuaj xyuas ntxiv tau pom tias nws poob 10 wt. % ntawm nws huab cua ntawm 300 degree [33]. Vim tias Tg ntawm cov khoom sib xyaw polymer tsis yog qhov tseeb nruab nrab ntawm Tg ntawm cov polymers uas tsim cov khoom sib xyaw nws zoo nkaus li ua ntau yam zoo li ntau qhov sib txawv nyob ntawm qhov muaj pes tsawg leeg ntawm cov khoom, cov qauv ntawm cov khoom sib xyaw, qhov hnyav ntawm lub cev. polymers, thiab lwm yam.

At qhov qis kawg ntawm qhov no, thermal activation tshwm sim tab sis yog hindered los ntawm steric constraints, qhov hnyav uas yuav txiav txim los ntawm tus txheeb ze tus nqi ntawm cov khoom dynamics [36].4.3.3. Polyurea.

Polyurea yog ib qho semicrystalline polymer khoom plig rau nws lub peev xwm piezoelectric, feem ntau siv los ua ib qho insulator, thiab tuaj yeem pom qhov kub thiab txias ruaj khov nrog piezoelectric econstant ntawm 15 mC / m2 uas nyob twj ywm kom txog thaum nws ncav cuag qhov kub ntawm 200 degree [38]; ib tug sawv cev ntawm tus qauv yuav pom nyob rau hauv daim duab 9. Yog hais tias sib xyaw nrog polyimide, cov hydrogen daim ntawv cog lus pub thiab txais nyob rau hauv lub blend enableself-assembly ntxiv rau ib tug ultralow dielectric tas li, avalue ntawm 1.56 thiab 1.94 nrog ib qho kev txo qis coj mus rau ib qho kev nce hauv cov concentration ntawm polyurea, uas yuav muaj txiaj ntsig zoo nyob rau hauv inhibition ntawm corrosion [25,38]; ib tug sawv cev ntawm polyimide-polyurea sib xyaw tej zaum yuav pom nyob rau hauv daim duab 10.

Tsis tas li ntawd, rau cov tsim poly (urea-imide) sib tov, ob lub rubbery toj siab cheeb tsam tshwm sim exponentially raws li qhov tshwm sim ntawm ob Tg cheeb tsam tshwm sim los ntawm cov mole feem cov ntsiab lus ntawm polyurea nyob rau hauv lub polyimide blockchain, uas nyob rau hauv lem nce lub cia modulus ntawm lub polymer.

Lub Tg ntawm copolymer nce nrog nce nyob rau hauv cov concentration ntawm high-Tg tivthaiv, qhov twg ib tug sharper nyhuv tshwm sim nrog ib tug ntxiv ntawm ib tug me ntsis ntxiv ntawm polyurea rau lub polyimide (nws yog tsim nyog sau cia hais tias lub degree ntawm imidization muaj me ntsis bearing ntawm tus cwj pwm no. nws txo qis raws li polyurea mole fractionincreases) raws li qhov tshwm sim ntawm kev txhawb nqa tus kheej, ntxiv hydrogen bonding [38].

Raws li qhov tshwm sim, polyimide-b-polyureaforms txheej txheej nrog lub neej kev cia siab ntawm 8 xyoo, siab dua li ntawm polyimide, muab kev tiv thaiv corrosion zoo dua [25], uas tuaj yeem pom hauv daim duab 11(a) thiab 11(b).

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