Kev sib raug zoo ntawm cov qauv thiab cov khoom ntawm cov polymers
Cov polymers yog cov macromolecules uas muaj cov chav me me rov ua dua, hu ua monomers. Muaj ntau hom polymers sib txawv pom muaj nyob rau hauv xwm thiab kuj tuaj yeem tsim tau los ntawm kev dag. Piv txwv ntawm cov polymers ntuj suav nrog cov protein, DNA, thiab cellulose, thaum cov polymers tsim muaj xws li polyethylene, polystyrene, nylon, thiab polypropylene. Ib yam li cov molecule loj, cov qauv ntawm cov polymer muaj qhov cuam tshuam loj rau nws cov khoom siv lub cev thiab tshuaj. Tsab xov xwm no tham txog yuav ua li cas piav qhia thiab siv kev sib raug zoo ntawm cov qauv thiab cov khoom ntawm cov polymers.
Cov Qauv Polymer
Cov polymers muaj peev xwm muab faib ua ntau pawg raws li lawv cov qauv thiab cov khoom sib xyaw. Lawv cov qauv tuaj yeem saib los ntawm ntau yam:
1. Cov Qauv Tseem Ceeb: Qhov no suav nrog cov kab ke ntawm cov monomers hauv cov saw polymer. Cov saw no tuaj yeem yog homopolymeric (tsim los ntawm tib lub monomer) lossis copolymeric (tsim los ntawm ob lossis ntau dua monomers sib txawv).
2. Cov Qauv Thib Ob thiab Thib Peb: Qhov no suav nrog kev hloov pauv thiab kev taw qhia ntawm cov saw hlau polymer hauv qhov chaw 3D. Cov qauv thib ob thiab thib peb yog qhov tseem ceeb heev hauv kev txiav txim siab cov khoom siv lub cev xws li qhov ceev, crystallinity, thiab ductility ntawm cov polymer.
3. Kev sib txuas ntawm cov ceg thiab kev sib txuas: Cov polymers muaj cov saw hlau uas sib txuas ntawm cov ceg lossis cov saw hlau uas sib txuas, uas cuam tshuam rau lub zog thiab kev ywj pheej. Cov polymers uas sib txuas ntawm cov ceg feem ntau muaj cov ntsiab lus yaj qis dua thiab cov khoom siv kho tshuab mos dua li cov polymers uas muaj ob peb ceg lossis tsis muaj ceg.
4. Kev Sib Txuas Lus: Qhov no yog qhov geometric regularity raws li cov saw polymer. Cov polymers tuaj yeem yog isotactic (txhua tus substituents nyob rau tib sab ntawm cov saw tseem ceeb), syndiotactic (substituents raug teeb tsa hauv txoj kev hloov pauv tas li raws li cov saw), lossis atactic (substituents raug teeb tsa random).
Cov Khoom ntawm Polymers
Cov qauv ntawm cov polymers ua rau muaj qee yam cuam tshuam rau lawv cov yam ntxwv li cas? Nov yog qee cov yam ntxwv ntawm cov polymers uas raug cuam tshuam los ntawm lawv cov qauv:
1. Lub Zog Tensile thiab Elasticity: Cov polymers sib txuas muaj lub zog tensile siab dua vim tias cov cross-links tiv thaiv cov saw hlau polymer kom tsis txhob tawg thaum rub. Cov khoom elastic ntawm cov polymers zoo li roj hmab kuj muaj feem cuam tshuam nrog cov cross-links, uas tuaj yeem rov qab mus rau lawv cov duab qub tom qab raug kev ntxhov siab.
2. Qhov nyuaj thiab tiv taus kub: Cov polymers crystalline muaj cov qauv ntom dua thiab feem ntau nyuaj dua li cov polymers amorphous, uas muaj cov qauv random ntau dua. Qhov nyuaj no kuj ua rau muaj kev tiv taus kub siab.
3. Qhov Kub thiab Kev Tawm Tsam: Cov qauv saw hlau hauv cov polymers feem ntau txo qhov ceev ntawm cov saw hlau, uas tuaj yeem txo lawv cov ntsiab lus yaj. Hais txog qhov tawv, cov qauv random xws li cov hauv atactic polymers muab lub peev xwm los nqus cov zog cuam tshuam siab dua li cov qauv ib txwm muaj.
4. Cov Khoom Siv Pom Kev: Cov polymers uas muaj cov pob zeb crystalline feem ntau yuav tsis pom tseeb vim muaj cov cheeb tsam uas muaj cov teeb ci ntsa iab. Qhov sib txawv, cov polymers amorphous tuaj yeem pom tseeb heev vim tias qhov kev txiav txim siab random hauv lawv cov qauv tso cai rau lub teeb hla dhau yooj yim dua.
5. Kev Nkag Tau thiab Kev Poob Qis Hauv Lub Cev: Cov qauv uas muaj qhov me me lossis cov ceg ntoo tuaj yeem ua rau cov polymer txoj kev nkag tau rau cov pa roj lossis cov kua dej ntau ntxiv. Ntawm qhov tod tes, kev sib txuas thiab qib siab ntawm crystallinity feem ntau txo qhov kev puas tsuaj hauv lub cev vim tias lawv ua rau cov polymer nyuaj rau cov kab mob me me tawg.
6. Kev Ywj Pheej thiab Kev Nplaum: Polyethylene (PE) yog ib qho piv txwv ntawm cov polymer ncaj nraim uas muaj kev ywj pheej siab. Cov polymers uas muaj ceg lossis kev sib txuas siab feem ntau tsis yooj ywm tab sis nyuaj dua. Lub caij no, kev nplaum feem ntau pom muaj nyob rau hauv cov polymers nrog cov qauv uas tuaj yeem cuam tshuam zoo nrog ntau qhov chaw.
Txoj Kev Ua Haujlwm thiab Kev Tshawb Fawb Txog Kev Sib Raug Zoo ntawm Cov Qauv thiab Cov Khoom Siv Polymer
Cov khoom siv tshuab, cua sov, thiab qhov muag ntawm cov polymers tuaj yeem kwv yees thiab hloov kho raws li kev nkag siab txog lawv cov qauv. Muaj ntau txoj hauv kev thiab kev xav piav qhia txog seb cov qauv cuam tshuam li cas rau cov khoom polymer.
Txoj Kev Xav Txog Saw Hlau Uas Yooj Yim
Raws li txoj kev xav no, qhov yooj ywm ntawm cov saw polymer yog los ntawm kev sib hloov dawb ntawm cov bonds sab hauv hauv cov saw. Cov qauv yooj ywm dua yuav ua rau cov polymers amorphous nrog cov khoom xws li yooj ywm siab thiab cov ntsiab lus yaj qis.
Qauv Boltzmann
Txoj kev xav no piav qhia txog kev faib tawm ntawm lub zog molecular hla ntau qib zog sib txawv. Hauv cov ntsiab lus ntawm polymers, nws pab piav qhia txog yuav ua li cas cov saw hlau polymer tuaj yeem tsim cov siv lead ua lossis tseem nyob tsis muaj zog thaum qhov kub hloov pauv.
Kev Tshawb Fawb Txog Elastomer Network
Qhov no cuam tshuam tshwj xeeb rau cov thermoset polymers xws li roj hmab, uas tuaj yeem rov qab mus rau lawv cov duab qub tom qab raug kev ntxhov siab. Lub network no muaj cov saw hlau polymer sib txuas, tsim cov roj hmab tshwj xeeb uas tseem ceeb rau cov ntawv thov xws li cov log tsheb.
Thermodynamics thiab Statistics ntawm Polymers
Txoj kev thermodynamic piav qhia txog qhov sib npaug ntawm entropy thiab enthalpy hauv kev txiav txim siab qhov xwm txheej kawg ntawm cov polymer, txawm tias crystalline lossis amorphous. Cov ntaub ntawv kwv yees cov yam ntxwv thiab txiav txim siab qhov kev faib tawm ntawm cov saw polymer ntev uas cuam tshuam rau nws cov khoom lub cev.
Kev Siv Txoj Kev Sib Raug Zoo Ntawm Cov Qauv Thiab Cov Khoom Ntawm Cov Polymers
Kev nkag siab txog kev sib raug zoo ntawm cov qauv polymer thiab cov khoom ua rau cov kws tshawb fawb thiab cov engineers tsim cov ntaub ntawv nrog kev ua tau zoo tshwj xeeb rau ntau yam kev siv, los ntawm cov khoom siv dav hlau mus rau cov khoom siv kho mob mus rau cov khoom ntim khoom noj.
1. Cov Khoom Siv Sib Xyaws: Cov polymers nrog cov qauv txhawb nqa nrog cov pa roj carbon lossis cov iav fibers yog siv rau hauv kev siv dav hlau rau lub zog siab nrog qhov hnyav tsawg.
2. Cov Ntawv Xaiv: Cov polymers nrog cov qauv tshwj xeeb tuaj yeem siv rau cov ntawv uas xaiv rau cov ions lossis cov molecule tshwj xeeb, tseem ceeb rau kev ntxuav dej thiab cov thev naus laus zis kho mob.
3. Cov Polymers Uas Muaj Kev Coj Ua: Yog tias muaj kev doping kom raug, cov qauv polymer tuaj yeem hloov kho kom coj hluav taws xob, siv rau hauv cov khoom siv hluav taws xob yooj ywm xws li OLEDs thiab cov roj teeb polymer.
4. Kev Ntim Khoom thiab Kev Ntim Khoom: Cov qauv polymer uas muab kev ywj pheej siab thiab pob tshab yog qhov tseem ceeb rau kev ntim khoom noj uas tuaj yeem tswj tau qhov tshiab thiab ntev lub neej txee.
5. Cov Khoom Siv Kho Mob thiab Cov Khoom Uas Yaj Tau Hauv Lub Cev: Cov khoom siv polymer uas muaj cov qauv uas cov kab mob me me tuaj yeem yaj tau yog siv rau cov khoom siv kho mob uas tuaj yeem yaj tau hauv lub cev, txo qhov xav tau kev phais tshem tawm.
Los ntawm kev kawm thiab nkag siab txog kev sib raug zoo ntawm cov qauv polymer thiab cov khoom, peb tuaj yeem tsim cov ntaub ntawv zoo dua uas tsis yog tsuas yog ua tau raws li cov kev cai lij choj xwb tab sis kuj yog ib puag ncig zoo. Qhov no ua rau muaj kev tsim kho tshiab tsis kawg hauv kev tshawb fawb txog cov ntaub ntawv thiab kev tsim tshuaj lom neeg, uas muaj kev cuam tshuam loj heev rau ntau yam kev lag luam thiab lub neej txhua hnub.
