Cov Lus Nug Piv Txwv Sib Tham Txog Kev Sib Raug Zoo ntawm Cov Qauv thiab Cov Khoom ntawm Cov Polymers
Pendahuluuan
Cov polymers yog cov khoom siv tshwj xeeb uas muaj cov saw ntev, rov ua dua ntawm cov molecules hu ua monomers. Cov qauv polymer tuaj yeem sib txawv ntau, thiab cov kev hloov pauv no cuam tshuam ncaj qha rau lawv cov khoom siv lub cev. Kev nkag siab txog cov qauv polymer cuam tshuam li cas rau lawv cov khoom yog qhov tseem ceeb hauv ntau yam kev siv thev naus laus zis thiab kev lag luam. Tsab xov xwm no yuav tham txog ntau qhov teeb meem piv txwv uas tshawb nrhiav kev sib raug zoo ntawm cov qauv polymer thiab cov khoom.
1. Cov Polymers Lineal piv rau Cov Polymers Branched
Piv txwv lus nug 1:
Piav qhia seb cov qauv linear thiab branched ntawm polyethylene cuam tshuam li cas rau nws qhov melting point thiab mechanical strength.
Kev Sib Tham:
Polyethylene (PE) yog ib qho ntawm cov polymers siv ntau tshaj plaws thiab muaj ob hom qauv tseem ceeb: linear thiab branched.
– Polyethylene kab (HDPE):
Cov polyethylene no muaj cov qauv linear nrog me ntsis lossis tsis muaj branching. Vim tias nws cov saw hlau tuaj yeem sib haum ze ua ke, linear polyethylene muaj qhov ceev thiab crystallinity siab dua. Cov khoom no muab HDPE nws:
– Qhov kub siab dua: Vim yog qhov ceev dua, nws nyuaj rau cov molecule txav mus los, uas txhais tau tias xav tau ntau lub zog (kub) los yaj lawv.
- Lub zog kho tshuab siab dua: Cov qauv denser muab lub zog tensile zoo dua thiab tiv taus kev hloov pauv ntau dua.
– Polyethylene ceg (LDPE):
Cov polyethylene no muaj ib txoj saw hlau loj uas muaj ntau ceg luv luv. Cov ceg no tiv thaiv cov saw hlau loj kom tsis txhob sib haum ua ke, ua rau qhov ceev qis dua thiab tsis muaj crystallinity. Cov yam ntxwv no ua rau LDPE muaj:
- Qhov kub qis dua: Vim yog cov qauv xoob dua, cov molecule txav tau yooj yim dua, uas txhais tau tias qhov kub uas xav tau los yaj lawv qis dua.
- Lub zog kho tshuab qis dua: Qhov tsis muaj qhov ceev ua rau HDPE mos dua thiab tsis tshua muaj zog rau cov khoom hnyav.
2. Cov Khoom Siv Crystalline piv rau Cov Khoom Siv Amorphous
Piv txwv lus nug 2:
Cov qauv crystalline thiab amorphous hauv Polypropylene (PP) cuam tshuam li cas rau nws cov khoom pob tshab thiab tawv?
Kev Sib Tham:
Polypropylene tuaj yeem muaj cov qauv crystalline lossis amorphous, ob qho tib si muaj cov khoom sib txawv.
- Crystalline Polypropylene:
- Kev Ruaj Khov Siab Dua: Cov qauv crystalline ib txwm muaj kev ruaj khov dua thiab lub zog tensile.
– Tsis Muaj Pob Tshab: Cov qauv siv lead ua ib txwm muaj feem cuam tshuam lub teeb, ua rau cov khoom tsis muaj pob tshab lossis tsis pom tseeb.
- Amorphous Polypropylene:
- Ntau Yooj Yim Dua: Cov qauv tsis sib xws thiab tsawg dua ua rau muaj kev ywj pheej thiab elasticity ntau dua.
– Pob tshab dua: Vim tsis muaj cov qauv ib txwm uas tuaj yeem tawg lub teeb, amorphous polypropylene feem ntau yuav pob tshab dua.
3. Kev Cuam Tshuam ntawm Cov Pab Pawg Ua Haujlwm
Piv txwv lus nug 3:
Cov pab pawg ua haujlwm ester hauv polyesters cuam tshuam li cas rau hydrophobicity thiab kev tiv thaiv kev puas tsuaj?
Kev Sib Tham:
Cov pab pawg ua haujlwm hauv cov saw polymer tuaj yeem cuam tshuam rau nws cov khoom siv tshuaj lom neeg:
- Cov Khoom Hydrophobic:
Cov pawg ester (-COO-) hauv polyester muab cov khoom siv rau nws cov khoom hydrophobic. Cov pawg no tsis tshua muaj kev sib cuam tshuam nrog cov dej molecules, ua rau cov khoom siv tsis muaj dej - cov khoom muaj nqis heev hauv cov ntaub thiab cov ntawv thov ntim khoom.
- Kev Tiv Thaiv Kev Poob Qis:
Cov pawg ester yooj yim hydrolyzed, tshwj xeeb tshaj yog nyob rau hauv acidic lossis basic ib puag ncig. Yog li ntawd, polyester muaj qis dua kev tiv thaiv rau kev puas tsuaj tshuaj nyob rau hauv cov xwm txheej no. Txawm li cas los xij, nyob rau hauv nruab nrab ib puag ncig, polyester muaj zoo tiv thaiv rau kev puas tsuaj, ua rau nws haum rau ntau yam kev siv sab nraum zoov.
4. Cov Nyhuv ntawm Qhov Hnyav Molecular
Piv txwv lus nug 4:
Qhov hnyav molecular ntawm polystyrene cuam tshuam li cas rau nws cov viscosity thiab tensile zog?
Kev Sib Tham:
Qhov hnyav molecular yog ib qho ntawm cov yam tseem ceeb uas cuam tshuam rau cov khoom siv lub cev ntawm cov polymers:
- Qhov viscosity:
Thaum qhov hnyav ntawm cov molecular nce ntxiv, qhov viscosity (kev tiv thaiv kev ntws) ntawm polystyrene kuj nce ntxiv. Cov molecule ntev dua muaj ntau qhov sib cuag nrog ib leeg, tsim kom muaj kev tiv thaiv sab hauv ntau dua thaum cov khoom sim ntws.
- Lub zog tensile:
Polystyrene uas muaj qhov hnyav molecular siab dua feem ntau muaj lub zog tensile ntau dua. Cov saw ntev dua muab cov ntsiab lus xauv ntau dua thiab feem ntau kis kev ntxhov siab ntau dua thoob plaws hauv cov khoom, ua rau muaj zog dua, tiv taus kev hloov pauv ntau dua.
5. Kev Sib Txuas thiab Cov Khoom Elastomer
Piv txwv lus nug 5:
Qhov muaj cov crosslinks hauv cov roj hmab ntuj (polyisoprene) cuam tshuam li cas rau elasticity thiab kev tiv taus cov kuab tshuaj?
Kev Sib Tham:
Kev sib txuas yog hais txog kev sib txuas ntawm cov saw polymer uas tsim ib lub network peb-seem. Nws cov teebmeem yog raws li nram no:
- Kev ywj pheej:
Cov roj hmab ntuj tsim ua rau muaj kev ywj pheej thiab kev tiv thaiv kev hloov pauv. Cov kev sib txuas ua rau cov saw hlau polymer tsis txhob txav mus los thaum muaj kev nyuaj siab, ua rau cov khoom rov qab mus rau nws cov duab qub tom qab raug rub.
- Kev Tiv Thaiv Cov Tshuaj:
Cov polymers uas txuas nrog sib txuas ua rau cov tshuaj yaj tsis yooj yim yaj. Cov polymers uas sib txuas ua rau cov tshuaj yaj hauv cov tshuaj yaj nyuaj dua, ua rau nws nyob ruaj khov hauv ntau yam tshuaj lom neeg.
Xaus
Kev nkag siab txog kev sib raug zoo ntawm cov qauv polymer thiab cov khoom yog qhov tseem ceeb rau kev tsim cov ntaub ntawv thiab kev siv. Cov piv txwv uas tau tham txog npog ntau yam ntawm cov qauv polymer - los ntawm cov duab saw, crystallinity, qhov muaj cov pab pawg ua haujlwm, qhov hnyav molecular, thiab crosslinking - thiab cov yam no pab txhawb rau cov khoom sib txawv ntawm lub cev. Los ntawm kev nkag siab txog cov kev sib raug zoo no, peb tuaj yeem tsim cov polymers nrog cov khoom tshwj xeeb uas tsim rau cov ntawv thov tshwj xeeb.
Cov kev paub no tsis yog tsuas yog tseem ceeb rau cov kws ua tshuaj lom neeg thiab cov kws tshawb fawb txog cov ntaub ntawv xwb, tab sis kuj tseem ceeb rau cov lag luam uas siv cov polymers hauv cov khoom siv txhua hnub, yog li ntawd kev tsim kho tshiab thiab kev txhim kho tas mus li tuaj yeem ua tiav.
