Polyethylene - yog dab tsi? Kev siv ntawm polyethylene

2024 Tus sau: Howard Calhoun | [email protected]. Kawg hloov kho: 2023-12-17 10:28

polyethylene yog dab tsi? Nws cov yam ntxwv yog dab tsi? Yuav ua li cas yog polyethylene? Cov no yog cov lus nug uas txaus siab heev uas yuav raug hais hauv kab lus no.

cov ntaub ntawv dav dav

Polyethylene yog ib yam tshuaj uas yog cov saw hlau ntawm carbon atoms, txhua tus muaj ob lub hydrogen molecules txuas rau nws. Txawm hais tias muaj qhov sib xyaw ua ke, tseem muaj ob qhov kev hloov kho. Lawv txawv ntawm lawv cov qauv thiab, raws li, cov khoom. Thawj yog ib txoj saw hlau uas cov degree ntawm polymerization tshaj li ntawm tsib txhiab. Tus qauv thib ob yog ib ceg ntawm 4-6 carbon atoms uas txuas nrog rau cov saw tseem ceeb hauv txoj kev txiav txim siab. Yuav ua li cas linear polyethylene tau nyob rau hauv cov nqe lus dav dav? Qhov no yog ua tiav los ntawm kev siv cov catalysts tshwj xeeb uas cuam tshuam rau polyolefins ntawm qhov kub thiab txias (txog 150 degrees Celsius) thiab siab (txog 20 cua). Tab sis nws sawv cev li cas? Peb paub nws cov khoom siv tshuaj, tab sis nws lub cev muaj zog yog dab tsi?

yog dab tsi?

Polyethylene yog cov thermoplastic polymer uas cov txheej txheem crystallizationnqa tawm ntawm qhov kub thiab txias qis dua 60 degrees Celsius. Nws tsis yog pob tshab hauv txheej tuab, tsis ntub los ntawm dej, cov kuab tshuaj organic hauv chav sov tsis cuam tshuam rau nws. Yog hais tias qhov kub thiab txias tshaj 80 degrees Celsius, ces o ua ntej tshwm sim, thiab ces decomposition mus rau hauv aromatic hydrocarbons thiab halogen derivatives. Polyethylene yog ib yam khoom uas ua tau zoo tiv thaiv qhov tsis zoo ntawm cov kua qaub, ntsev thiab alkalis. Tab sis yog tias qhov kub siab tshaj 60 degrees Celsius, ces nitric thiab sulfuric acids tuaj yeem rhuav tshem nws sai. Rau gluing polyethylene cov khoom, lawv tuaj yeem kho nrog oxidizing cov neeg ua haujlwm, ua raws li kev siv cov khoom tsim nyog.

Yuav ua li cas yog polyethylene?

Siv rau qhov no:

• High pressure (low density) method. Polyethylene yog tsim los ntawm kev kub siab, uas yog nyob rau hauv thaj tsam ntawm 1,000 txog 3,000 atmospheres ntawm qhov kub ntawm 180 degrees Celsius. Oxygen ua tus pib.
• Kev siab qis (siab ceev) txoj kev. Nyob rau hauv cov ntaub ntawv no, polyethylene yog tsim nyob rau hauv ib tug siab ntawm tsawg kawg yog tsib cua nyob rau hauv ib tug kub ntawm 80 degrees Celsius siv cov organic hnyav thiab Ziegler-Natta catalysts.
• Thiab muaj ib lub voj voog ntau lawm ntawm linear polyethylene, uas tau hais los saum toj no. Nws yog nruab nrab ntawm qhov thib ob thiab thawj cov ntsiab lus.

Nco ntsoov tias cov no tsis yog siv thev naus laus zis nkaus xwb. Yog li ntawd,Kev siv cov metallocene catalysts kuj muaj ntau heev. Lub ntsiab lus ntawm cov thev naus laus zis no nyob rau hauv qhov tseeb tias los ntawm nws qhov tseem ceeb ntawm cov khoom siv polymer ua tiav, thaum ua kom lub zog ntawm cov khoom. Nyob ntawm seb cov qauv thiab cov khoom xav tau dab tsi thaum siv ib qho monomer, kev xaiv ntawm ib txoj kev tau txais tshwm sim. Nws kuj tseem tuaj yeem cuam tshuam los ntawm qhov kub thiab txias, lub zog, hardness thiab ntom ntom.

Vim li cas thiaj muaj qhov sib txawv no?

Lub ntsiab yog vim li cas rau qhov sib txawv ntawm cov khoom yog cov ceg ntawm macromolecules. Yog li, qhov loj dua, qhov tsawg crystallinity thiab siab dua elasticity ntawm polymer. Vim li cas thiaj tseem ceeb? Qhov tseeb yog tias txhua yam khoom ntawm polyethylene loj hlob nrog rau nws qhov ceev thiab molecular hnyav. Cia peb saib ib qho piv txwv me me. Polyethylene daim ntawv muaj qhov tseem ceeb rigidity thiab opacity. Tab sis yog siv txoj kev tsawg ntom ntom, ces cov khoom siv yuav muaj qhov hloov tau zoo thiab txheeb ze pom los ntawm nws. Vim li cas thiaj muaj ntau yam khoom zoo li no? vim muaj kev khiav hauj lwm sib txawv. Yog li, polyethylene copes zoo nrog shocks loads. Nws kuj tolerates Frost zoo. Kev khiav hauj lwm kub ntawm cov khoom no yog los ntawm -70 txog +60 Celsius. Txawm hais tias ib tus neeg lub npe tau yoog rau qhov sib txawv me ntsis - los ntawm -120 txog +100. Qhov no cuam tshuam los ntawm qhov ntom ntawm polyethylene thiab nws cov qauv ntawm qib molecular.

Khoom tshwj xeeb

Nws yuav tsum tau muab sau tseg ib qho tseem ceeb drawback - kev laus sai ntawm polyethylene. Tab sis qhov no yog fixable. Kev nce hauv kev pabcuam lub neej yog ua tiav ua tsaug rau cov tshuaj antioxidant tshwj xeeb, uas tuaj yeem yog carbon dub, phenols lossis amines. Nws kuj yuav tsum tau sau tseg tias cov khoom siv ntom ntom ntom ntom ntom ntom ntom yog ntau dua viscous, yog li nws tuaj yeem yooj yim ua rau cov khoom lag luam. Tsis hais txog cov khoom hluav taws xob. Polyethylene, vim qhov tseeb tias nws tsis yog-polar polymer, yog cov khoom siv hluav taws xob zoo tshaj plaws. Vim li no, qhov permeability thiab qhov poob tangent hloov me ntsis los ntawm kev hloov pauv hauv av, qhov kub thiab txias (hauv thaj tsam ntawm -80 txog +100) thiab zaus ntawm hluav taws xob teb. Ib qho tshwj xeeb yuav tsum tau sau tseg ntawm no. Yog li, yog tias muaj cov catalyst residues hauv polyethylene, qhov no ua rau muaj kev nce hauv dielectric poob tangent, uas ua rau qee qhov deterioration ntawm insulating zog. Zoo, tam sim no peb tau xav txog qhov xwm txheej dav dav. Tam sim no cia peb paub meej.

LDPE yog dab tsi?

Qhov no yog cov khoom siv elastic, hnav, crystallizing nrog lub tshav kub kub ntawm -80 txog +100 degrees Celsius. Nws muaj qhov ci ntsa iab. Lub iav hloov pauv pib ntawm -20. Thiab melting yog nyob rau hauv thaj tsam ntawm 120-135. Nws yog tus cwj pwm los ntawm kev cuam tshuam zoo zog thiab kub tsis kam. Qhov ntom ntawm polyethylene cuam tshuam rau cov khoom tau txais. Yog li, nrog rau nws, lub zog, rigidity, hardness thiab tshuaj tiv thaiv nce. Tab sis nyob rau tib lub sij hawm, tus nyiam stretch thiab permeability txo.rau vapors thiab gases. Nws yog tsis yooj yim sua kom tsis txhob nco lub creep uas tau pom thaum lub sij hawm ntev loading. Xws li polyethylene yog lom lom thiab tuaj yeem siv tau yooj yim. Uas yog heev pab tau nyob rau hauv niaj hnub tej yam kev mob. Hais txog kev siv polyethylene, nws yuav tsum tau muab sau tseg tias nws yog siv rau kev tsim cov ntim thiab ntim. Yog li, kwv yees li ib feem peb ntawm kev tsim khoom mus rau kev tsim cov tshuab moulding ntim uas siv rau hauv kev lag luam khoom noj, tshuaj pleev ib ce, tsheb, tsev neeg, lub zog thiab cov yeeb yaj kiab. Tab sis koj tuaj yeem ua tau raws li nws thaum tsim cov kav dej thiab cov kav dej. Ib qho txiaj ntsig tseem ceeb ntawm cov khoom siv no yog nws cov kav ntev, tus nqi qis thiab yooj yim ntawm vuam.

YHDPE

Qhov no yog cov khoom siv elastic, lub teeb yuag, crystallizing nrog lub tshav kub tsis kam (tsis muaj load) txij li -120 txog +90 degrees Celsius. Cov khoom kuj tseem muaj zog nyob ntawm qhov ntom ntawm cov khoom tshwm sim. Qhov no ua rau kom muaj zog, hardness, nruj thiab tshuaj tsis kam. Nyob rau tib lub sijhawm, lub thickness ntawm polyethylene cuam tshuam qhov cuam tshuam tsis kam, elongation, tawg tsis kam thiab permeability rau vapors thiab gases. Tsis tas li ntawd, nws tsis yog qhov ruaj khov thiab muaj qhov cuam tshuam tsis zoo ntawm cov khoom me me. Nws yuav tsum tau muab sau tseg tias cov tshuaj tiv thaiv siab heev thiab zoo heev dielectric yam ntxwv. Los ntawm qhov tsis zoo - xws li polyethylene raug cuam tshuam los ntawm cov rog, roj thiab hluav taws xob ultraviolet. Biologically inert, tuaj yeem siv tau yooj yim. Nws kuj ua taukom characterize thiab resistant rau hluav taws xob. Kev siv cov polyethylene high-density feem ntau yog tsim los ntawm kev siv tshuab, khoom noj khoom haus thiab kev ua liaj ua teb films. Txawm li cas los xij, qhov no tsis yog qhov kev xaiv nkaus xwb.

Txoj kab polyethylene

Nws yog cov khoom siv elastic crystallizing. Nws tuaj yeem tiv taus kub txog 118 degrees Celsius. Tsis tas li ntawd ib qho tseem ceeb kom zoo dua ntawm cov khoom no yog nws tsis kam mus tawg, tshav kub tsis kam thiab cuam tshuam lub zog. Nws yog siv rau zus tau tej cov packing, muaj peev xwm thiab ntim. Qhov no polyethylene muab dab tsi? Cov yam ntxwv ntawm cov khoom no yog siab heev nyob rau hauv kev sib piv nrog rau cov analogue uas tau txais los ntawm txoj kev tsis tshua muaj siab. Yog li ntawd, nws muaj cov khoom zoo heev. Tab sis tseem, raws li txoj cai, nws tsis tuaj yeem sib npaug HDPE.

Yuav ua li cas cov khoom tuaj yeem nthuav tawm?

Yog li, peb twb tau txiav txim siab hom tseem ceeb ntawm polyethylene. Nws tsim nyob rau hauv daim ntawv twg? Qhov nrov tshaj plaws yog polyethylene ntawv thiab zaj duab xis. Cov pwm no tuaj yeem ua los ntawm cov khoom siv ntom ntom. Txawm hais tias tseem muaj qee qhov kev nyiam. Yog li, txoj kev tsis tshua muaj siab yog siv dav kom tau txais cov yeeb yaj kiab elastic thiab nyias. Qhov dav ntawm cov khoom tshwm sim, raws li txoj cai, ncav cuag 1400 millimeters, thiab qhov ntev yog 300 meters. Linear thiab high-density polyethylene yog nruj dua, yog li lawv siv rau cov qauv uas yuav tsum tsis txhob cuam tshuam: tib cov nplooj ntawv, kav dej, molded thiab molded khoom, thiab lwm yam.

Zaj lus

Thiab thaum kawg, ib tus tsis tuaj yeem hais txog cov ntaub ntawv tswj hwm, raws li cov khoom siv polyethylene. GOST 16338-85 yog lub luag haujlwm rau cov khoom tsim los ntawm kev kub siab. Nws tau ua haujlwm txij li xyoo 1985. GOST 16337-77 tswj cov teeb meem ntsig txog kev kub siab polyethylene. Nws tseem laus dua thiab hnub rov qab mus rau xyoo 1977. Cov ntaub ntawv tswj hwm no muaj cov ntaub ntawv hais txog qhov yuav tsum tau ua ntawm cov khoom siv los ntawm cov yeeb yaj kiab, ntim khoom thiab ntau yam khoom tsim. Ntxiv mus, nws yuav tsum tau muab sau tseg ib tug ntau yam ntawm daim ntawv thov ntawm lub resulting khoom thiab nws hom ntau haiv neeg. Yog li, piv txwv li, cov yeeb yaj kiab polyethylene muaj zog muaj ntau heev. Lawv peculiarity yog tias, nrog tib lub thickness, lawv yog ib tug txiav saum toj no nyob rau hauv lawv cov khoom dua li cov qauv khoom zoo tib yam. Cov ntaub pua rooj, hnab thiab ntau yam khoom siv tau zoo yog tsim los ntawm tib lub zog polyethylene zaj duab xis. Thiab lawv cov khoom yog tau los ntawm kev qhia txog cov xov tshwj xeeb los ntawm ntuj lossis hluavtaws fibers.