Vim li cas PMMA thiaj li muaj zog?
Jan 14, 2024
Vim li cas PMMA thiaj li muaj zog?
Taw qhia:
PMMA, tseem hu ua polymethyl methacrylate, yog cov khoom siv dav siv polymer paub txog nws lub zog tshwj xeeb. Hauv tsab xov xwm no, peb delve rau hauv cov laj thawj tom qab PMMA lub zog thiab tshawb xyuas cov yam tseem ceeb uas ua rau nws muaj zog. Los ntawm nws cov qauv tshuaj mus rau nws cov txheej txheem ua, peb tshuaj xyuas kev tshawb fawb thiab kev tsim vaj tsev tom qab cov khoom zoo kawg li no.
Chemical Structure thiab Bonding:
Ib qho ntawm cov ntsiab lus tseem ceeb uas ua rau lub zog ntawm PMMA yog nyob rau hauv nws cov qauv tshuaj lom neeg thiab kev sib raug zoo. PMMA yog pob tshab thermoplastic uas belongs rau tsev neeg ntawm acrylic polymers. Nws cov chav nyob rov muaj xws li methyl methacrylate (MMA) monomers, uas tau koom nrog ester linkage.
MMA monomers muaj ob daim ntawv cog lus ntawm cov pa roj carbon thiab oxygen atoms, uas ua rau lawv mus rau cov txheej txheem ntawm polymerization. Thaum lub sij hawm polymerization, ob daim ntawv cog lus tawg, thiab cov khoom siv tshuaj lom neeg tshiab tsim ntawm cov monomers, uas ua rau muaj kev sib txuas ntawm peb sab. Cov qauv network no muab PMMA nrog nws lub zog zoo kawg nkaus thiab nruj.
Ntxiv mus, qhov sib txuas ester hauv PMMA pab txhawb rau nws cov khoom siv kho tshuab zoo dua. ester daim ntawv cog lus paub txog nws lub zog siab, ua rau nws tiv taus kev tawg nyob rau sab nraud. Qhov kev sib raug zoo ntawm cov monomers no txhim kho lub zog ntawm PMMA.
Molecular Luj thiab Chain Arrangement:
Qhov hnyav molecular ntawm PMMA plays lub luag haujlwm tseem ceeb hauv kev txiav txim siab nws lub zog. Ntau dua molecular hnyav polymers zoo li yuav muaj kev txhim kho cov khoom siv vim muaj kev sib cuam tshuam ntawm intermolecular. PMMA nrog qhov hnyav dua molecular pom muaj zog tensile ntau dua, cuam tshuam tsis kam, thiab nruj piv rau qis dua molecular hnyav counterparts.
Tsis tas li ntawd, kev npaj ntawm cov saw hlau polymer hauv cov khoom cuam tshuam lub zog ntawm PMMA. Ib qho kev txiav txim siab heev ntawm cov saw hlau, feem ntau hu ua crystallinity, yog paub los txhim kho cov khoom ntawm cov khoom siv polymers. Txawm li cas los xij, kev ua tiav qib siab ntawm crystallinity hauv PMMA yog qhov nyuaj vim nws qhov amorphous xwm. Txawm li cas los xij, los ntawm kev ua tib zoo tswj cov txheej txheem ua haujlwm thiab ntxiv qee yam khoom ntxiv, nws muaj peev xwm txhawb nqa cov saw hlau sib dhos thiab txhim kho lub zog ntawm PMMA.
Reinforcement Techniques thiab Fillers:
Txhawm rau txhawm rau txhim kho lub zog ntawm PMMA, ntau yam kev txhawb nqa thiab kev muab tub lim tuaj yeem ua haujlwm. Cov tswv yim no tsom mus ntxiv dag zog rau cov polymer matrix los ntawm kev sib xyaw cov ntaub ntawv ntxiv uas tuaj yeem tiv taus kev ntxhov siab ntau dua thiab hnyav.
Ib txoj hauv kev ntxiv dag zog yog suav nrog cov iav fibers lossis carbon nanotubes rau hauv PMMA matrix. Cov fibers los yog nanotubes ua raws li tus neeg sawv cev txhawb zog, ua kom lub zog thiab nruj ntawm cov khoom. Cov khoom sib xyaw ua ke, hu ua fiber ntau ntxiv PMMA, nthuav tawm cov khoom siv kho tshuab zoo heev thiab tau siv dav hauv kev siv engineering.
Lwm cov txheej txheem siv feem ntau yog kev ntxiv cov fillers, xws li silica lossis calcium carbonate hais, rau hauv PMMA matrix. Cov fillers no ua raws li kev ntxhov siab, cuam tshuam kev nthuav tawm ntawm cov kab nrib pleb thiab txhim kho tag nrho cov tawv nqaij ntawm cov khoom. Los ntawm dispersing cov fillers kom tsim nyog, lub zog thiab kev cuam tshuam ntawm PMMA tuaj yeem txhim kho tau zoo.
Txheej txheem txheej txheem:
Cov txheej txheem ua haujlwm ua haujlwm thaum lub sijhawm tsim khoom ntawm PMMA kuj tseem ua rau nws lub zog. Ob txoj kev siv feem ntau yog extrusion thiab txhaj tshuaj molding.
Thaum lub sij hawm extrusion, PMMA resin yog rhuab thiab yuam los ntawm ib tug tuag los tsim ib tug nruam zoo, xws li ib daim ntawv los yog pas nrig. Cov txheej txheem extrusion dlhos cov polymer chains thiab txo qhov tsis xws luag los yog tsis muaj zog cov ntsiab lus nyob rau hauv cov khoom, uas ua rau ib tug muaj zog kawg khoom.
Kev txhaj tshuaj molding yuav tsum tau txhaj cov molten PMMA rau hauv lub pwm kab noj hniav nyob rau hauv siab. Cov txheej txheem no tso cai rau cov duab nyuaj tsim thaum tuav lub zog ntawm cov khoom siv. Cov kev kub ntxhov thaum lub sij hawm txhaj tshuaj molding pab ua kom tiav ib homogeneous tis ntawm polymer chains, ua rau txhim khu lub zog.
Impact Resistance thiab Toughness:
Sib nrug los ntawm nws lub zog, PMMA kuj nthuav tawm zoo heev cuam tshuam thiab toughness. Thaum cov ntaub ntawv zoo li iav zoo li tawg thaum muaj kev cuam tshuam, PMMA qhia txog qib siab dua ntawm kev tiv thaiv tawg.
Lub zog ntawm PMMA tuaj yeem raug ntaus nqi rau nws qhov hnyav molecular, uas tso cai rau cov saw hlau polymer kom nqus tau lub zog thaum muaj xwm txheej. Tsis tas li ntawd, lub xub ntiag ntawm fillers, raws li tau hais ua ntej, txhim kho lub zuag qhia tag nrho toughness los ntawm kev tiv thaiv tawg propagation. Cov yam ntxwv tshwj xeeb no ua rau PMMA qhov kev xaiv tsim nyog rau cov ntawv thov uas muaj kev cuam tshuam kev cuam tshuam tseem ceeb, xws li hauv tsheb cua thiab cov khoom siv tiv thaiv.
Xaus:
Hauv kev xaus, PMMA lub zog tshwj xeeb tuaj yeem raug ntaus nqi rau nws cov qauv tshuaj, qhov hnyav molecular, kev sib txuas, kev siv zog, kev muab tub lim, thiab cov txheej txheem ua haujlwm. Nws qhov tshwj xeeb sib xyaw ua ke ntawm lub zog, cuam tshuam tsis kam, thiab toughness ua rau nws muaj ntau yam khoom siv rau ntau yam kev siv. Kev nkag siab ntawm cov hauv paus ntsiab lus uas ua rau PMMA lub zog yog qhov tseem ceeb rau nws txoj kev txhim kho txuas ntxiv thiab kev siv hauv ntau hom kev lag luam.