Qhov sib txawv tseem ceeb ntawm epoxy thiab polyurethane yog tias epoxy muaj epoxide pawg thaum polyurethanes muaj cov urethane txuas. Hauv daim ntawv thov kev pom, qhov sib txawv tseem ceeb ntawm epoxy thiab polyurethane yog tias cov epoxy resins tuaj yeem tiv taus qhov kub thiab txias thaum cov polyurethanes tuaj yeem tiv taus kub.
Ob leeg epoxy thiab polyurethane yog cov khoom siv polymer. Ib tug polymer yog ib tug macromolecule uas muaj ib tug loj tus naj npawb ntawm me me rov qab units (monomers). Cov monomers sib xyaw ua ke los ua ib lub polymer. Lub sij hawm epoxy yog siv rau lub npe epoxy resins uas muaj epoxy functional pawg nyob rau hauv ib tug rov qab qauv. Polyurethane kuj yog cov khoom siv polymer uas muaj cov urethane txuas.
Epoxy yog dab tsi?
Epoxy lossis epoxy resin yog chav kawm ntawm cov khoom siv polymer uas muaj cov pab pawg ua haujlwm epoxy. Nws yog ib daim ntawv ntawm polyurethane. Cov polymers no tuaj yeem yog qhov hnyav molecular lossis siab molecular hnyav polymers nrog tsawg kawg ob pawg epoxide. Hauv kev tsim khoom lag luam, feem ntau cov roj av yog lub hauv paus rau epoxy resin ntau lawm. Txawm li cas los xij, muaj qee qhov chaw cog qoob loo ib yam nkaus.
Epoxy resins tuaj yeem cuam tshuam nrog ib leeg ntawm catalytic homopolymerization thiab tsim kev sib txuas ntawm lawv. Los yog lwm yam, epoxy resins tuaj yeem cuam tshuam nrog qee qhov sib txuas xws li;
- Amines
- Acids
- Phenols
- Alcohols
- Thiols
Cov no yog co-reactants. Qee lwm lub npe rau cov co-reactants yog hardeners lossis curatives. Yog li, cov kev sib txuas sib txuas uas cov epoxy resins tau nrog cov kev kho mob no yog hais txog "kho". Cov txheej txheem crosslinking tsim cov thermosetting polymer uas muaj cov tshuaj lom neeg thiab cov khoom siv zoo.
Daim duab 01: Epoxy Resins
Txoj kev suav ntawm qhov tshwj xeeb ntawm epoxy pawg tam sim no hauv epoxy resin yog raws li hauv qab no:
- Qhov piv ntawm cov epoxy pawg thiab qhov loj ntawm cov khoom siv polymer muab qhov tshwj xeeb ntawm epoxide pawg hauv epoxy resin.
- Chav ntsuas rau qhov ntsuas no yog "mol / kg". Peb hu lo lus no qee zaum ua "tus lej epoxide".
Qee yam thiab tseem ceeb ntawm Epoxy Resins
Bisphenol A Epoxy Resin
Hom epoxy resins no yog tshwm sim los ntawm kev sib xyaw ntawm epichlorohydrin thiab bisphenol A. qhov kev sib xyaw no muab bisphenol A diglycidyl ethers. Yog tias peb ntxiv cov bisphenol A (piv rau epichlorohydrin), nws muab cov khoom hnyav molecular polymer. Cov khoom siv polymer no yog linear thiab yog cov khoom siv crystalline semi-solid.
Bisphenol F Epoxy Resin
Ntawm no peb siv bisphenol F nyob rau hauv qhov chaw ntawm bisphenol A, tab sis txoj kev tsim ntawm cov polymer yog tib yam li bisphenol A epoxy resin (raws li tau tham saum toj no).
Novolac Epoxy Resin
Novolac epoxy resins tsim thaum phenols hnov mob nrog formaldehyde thiab nkag mus glycosylation nrog epichlorohydrin. Feem ntau ntawm cov sij hawm, cov khoom siv polymer no qhia tau hais tias muaj tshuaj lom neeg ua haujlwm siab thiab kub ua haujlwm tab sis tsis yooj yim.
Aliphatic Epoxy Resin
Cov polymers no tsim los ntawm glycosylation ntawm aliphatic cawv lossis polyols. Cov khoom siv polymer no muaj viscosity tsawg ntawm chav tsev kub.
YPolyurethane yog dab tsi?
Polyurethane yog cov khoom siv polymer uas muaj urethane txuas (carbamate linkages). Isocyanates thiab polyols dhau los ua polymerization los ua ib qho polyurethane. Txawm hais tias lub npe polyurethane muab lub tswv yim tias cov polymer muaj urethane monomers, nws qhov tseeb, muaj cov urethane txuas, tsis yog monomers.
Daim duab 02: Lub rooj zaum ua los ntawm Polyurethane
Thaum siv cov monomers rau kev tsim cov polyurethanes, cov isocyanates yuav tsum muaj tsawg kawg yog ob pawg ua haujlwm uas tso cai rau nws mus rau polymerization. Ntxiv mus, polyol kuj yuav tsum muaj tsawg kawg yog ob pawg hydroxyl ib molecule. Cov tshuaj tiv thaiv ntawm cov monomers nyob rau hauv no polymerization yog ib qho exothermic cov tshuaj tiv thaiv nyob rau hauv uas kub yog muab tawm los ntawm cov tshuaj tiv thaiv sib tov. Cov urethane txuas cov ntaub ntawv thaum -N=C=O pawg ntawm isocyanate hnov mob nrog -OH pawg ntawm cawv los ua ib qho kev sib txuas ntawm urethane (-NH-C(=O)-O).
Qhov txawv ntawm Epoxy thiab Polyurethane yog dab tsi?
YEpoxy vs Polyurethane |
|
| Epoxy lossis epoxy resin yog chav kawm ntawm cov khoom siv polymer uas muaj cov pab pawg ua haujlwm epoxy. | Polyurethane yog cov khoom siv polymer uas muaj urethane txuas. |
| monomers | |
| Cov monomers rau epoxy resins yog phenols thiab epichlorohydrin, tab sis cov monomers yuav txawv nyob ntawm seb hom epoxy resin. | Cov monomers rau polyurethane yog polyols thiab isocyanates. |
| Qhia piv tsis zoo rau cov organic acids | Qhia siab tiv thaiv corrosion, inorganic acids, alkali solvents, organic alkalis thiab ntau lwm cov kuab tshuaj |
| Heat Tolerance | |
| Epoxy resins tuaj yeem tiv taus qhov kub nruab nrab. | Polyurethanes tuaj yeem tiv taus qhov kub thiab txias. |
Summary - Epoxy vs Polyurethane
Epoxies yog hom polyurethanes. Cov polymers no tau txais lawv lub npe raws li cov kev sib txuas rov qab tam sim no hauv cov khoom siv polymer es tsis txhob siv cov monomers siv rau kev tsim khoom. Qhov sib txawv ntawm epoxy thiab polyurethane yog tias epoxy resin muaj epoxide pawg thaum polyurethanes muaj urethane txuas.
