Qhov sib txawv tseem ceeb ntawm crosslinking thiab gelation yog tias crosslinking yog tsim ntawm ionic lossis covalent bonds ntawm polymer chains, whereas gelation yog tsim ntawm gel.
Crosslinking yog txheej txheem ntau hauv cov ntaub ntawv polymer. Gelation kuj yog ib hom crosslinking. Txawm li cas los xij, nws tshwj xeeb tsim cov gel es tsis yog ib qho yooj yim crosslinked polymer khoom.
Crosslinking yog dab tsi?
Crosslinking yog qhov tsim ntawm covalent bonds ntawm ob lub polymer chains. Cov ntawv cog lus tshuaj no tuaj yeem yog ionic bonds lossis covalent bond - feem ntau lawv yog covalent bonds. Crosslinked polymers yog polymers muaj crosslinks ntawm polymer chains. Cov ntawv cog lus no tsim thaum lub sijhawm txheej txheem polymerization (tsim ntawm cov khoom siv polymer). Qee zaum crosslinks daim ntawv tom qab ua tiav ntawm polymerization ib yam nkaus.
Vim tias crosslinks ntawm cov saw hlau polymer muaj zog dua li qhov kev nyiam ntawm cov khoom sib txuas, cov polymers tsim los ntawm kev sib txuas yog ruaj khov thiab muaj zog dua. Cov polymers no tshwm sim nyob rau hauv ob qho tib si hluavtaws cov ntaub ntawv thiab raws li ib txwm tshwm sim polymers. Crosslinks yog tsim los ntawm cov tshuaj tiv thaiv nyob rau hauv lub xub ntiag ntawm crosslinking reagents. Feem ntau piv txwv ntawm crosslinked polymers yog vulcanized roj hmab. Txij li cov roj hmab ntuj tsis tawv lossis nruj txaus, cov roj hmab yog vulcanized. Ntawm no, roj hmab yog rhuab nrog leej faj, yog li cov sulfur molecules tsim covalent bonds nyob rau hauv cov roj hmab polymer chains, txuas cov chains nrog ib leeg. Tom qab ntawd cov roj hmab los ua cov khoom tawv thiab tawv uas yog cov khoom ruaj khov.
Tus nqi ntawm crosslinking muab qib ntawm crosslinking ib mole ntawm cov khoom. Peb tuaj yeem ntsuas qhov degree ntawm crosslinking los ntawm kev sim o. Hauv qhov kev sim no, cov khoom raug muab tso rau hauv ib lub thawv nrog cov kuab tshuaj haum. Tom qab ntawd qhov kev hloov ntawm huab hwm coj lossis qhov hloov ntawm qhov ntim yog ntsuas. Ntawm no, yog tias qhov degree ntawm crosslinking tsawg, cov khoom swells ntau dua.
Gelation yog dab tsi?
Y Gelation yog tsim los ntawm cov gel los ntawm kev sib xyaw ntawm cov polymers. Ntawm no, branched polymers ua rau tsim kev sib txuas ntawm cov ceg. Qhov no yog ib hom kev sib txuas sib txuas, thiab nws ua rau kev tsim ntawm lub network loj polymer. Thaum lub sij hawm txheej txheem ntawm kev tsim network no, ib qho macroscopic molecule tsim ntawm qee qhov taw tes, thiab peb hu qhov point no ua tus gel point. Ntawm no, qhov sib tov poob nws fluidity thiab viscosity. Lub caij no, nws yuav loj heev. Lub gel taw tes ntawm ib qho system tuaj yeem txiav txim siab tau yooj yim los ntawm kev soj ntsuam qhov hloov pauv sai ntawm viscosity. Tom qab ua tiav ntawm kev tsim cov khoom siv hauv lub network tsis kawg, peb tuaj yeem hu nws ua "gel", thiab cov gel no tsis yaj hauv cov kuab tshuaj. Txawm li cas los xij, cov gel tuaj yeem raug o.
Ib lub gel tuaj yeem tsim tau ob txoj hauv kev: kev sib txuas ntawm lub cev lossis tshuaj lom neeg sib txuas. Ntawm cov txheej txheem no, cov txheej txheem gelation lub cev muaj kev sib txuas ntawm lub cev ntawm cov molecules polymer. Cov ntawv cog lus lub cev tuaj yeem suav nrog cov kev sib txuas uas tsis yog tshuaj lom neeg. Txawm li cas los xij, cov txheej txheem kev sib txuas ntawm cov tshuaj muaj xws li covalent bond tsim ntawm polymer molecules.
Dab tsi yog qhov txawv ntawm Crosslinking thiab Gelation?
Qhov sib txawv tseem ceeb ntawm crosslinking thiab gelation yog tias crosslinking yog tsim cov ionic lossis covalent bonds ntawm cov saw hlau, hos gelation yog hais txog kev tsim cov gel. Ntxiv mus, crosslinking cov ntaub ntawv vim yog qhov sib ntxiv ntawm crosslinking tus neeg saib xyuas thaum cov ntaub ntawv gelation vim qhov hloov pauv sai ntawm cov viscosity ntawm qhov sib ntxiv ntawm cov neeg sawv cev crosslinking. Gelation kuj yog ib hom kev sib txuas.
Hauv qab infographic tabulates ntau qhov sib txawv ntawm crosslinking thiab gelation.
Summary – Crosslinking vs Gelation
Crosslinking yog txheej txheem ntau hauv cov ntaub ntawv polymer. Gelation kuj yog ib hom crosslinking. Txawm li cas los xij, nws tshwj xeeb tsim cov gel es tsis yog ib qho yooj yim crosslinked polymer khoom. Qhov sib txawv tseem ceeb ntawm crosslinking thiab gelation yog tias crosslinking yog tsim los ntawm ionic lossis covalent bonds ntawm polymer chains, whereas gelation yog hais txog kev tsim cov gel.
