Polyethylene kav (PE kav) yog dav siv nyob rau hauv niaj hnub pipeline engineering. Lawv cov qauv tsim tshwj xeeb txiav txim siab lawv lub cev zoo heev thiab kev cia siab ntev ntev -. Los ntawm cov txheej txheem microscopic molecular mus rau macroscopic interlayer qauv, cov qauv ntawm cov kav dej polyethylene tuaj yeem muab faib ua ntau txheej, txhua qhov muaj feem cuam tshuam rau kev ua haujlwm kawg.
I. Basic Structure ntawm Qib Molecular
Cov khoom tseem ceeb ntawm cov kav dej polyethylene yog polyethylene (PE), thermoplastic polymer compound tsim los ntawm cov tshuaj tiv thaiv polymerization ntawm ethylene monomers. Raws li cov txheej txheem polymerization sib txawv thiab kev npaj cov saw molecular, polyethylene tuaj yeem muab faib ua qis- ntom polyethylene (LDPE), nruab nrab- ntom polyethylene (MDPE), thiab siab- ntom polyethylene (HDPE). Ntawm lawv, HDPE, vim nws cov hlua khi molecular nruj thiab cov crystallinity siab, tau dhau los ua cov khoom siv rau cov kav dej loj.
Nyob rau theem molecular, linear ntev - cov qauv saw ntawm HDPE cov ntaub ntawv tau txiav txim siab rau thaj tsam crystalline los ntawm van der Waals rog, thaum cov cheeb tsam amorphous sau qhov chaw nruab nrab ntawm thaj tsam crystalline. Qhov kev sib koom ua ke ntawm crystalline thiab amorphous cheeb tsam endows polyethylene kav nrog zoo rigidity (los ntawm cov crystalline cheeb tsam) thiab toughness (los ntawm cov cheeb tsam amorphous). Tsis tas li ntawd, cov tsis yog - pawg polar nyob rau hauv cov saw molecular muab nws cov tshuaj lom neeg ruaj khov heev, ua rau nws tiv taus ntau yam kua qaub thiab alkali corrosive media.
II. Microstructural yam ntxwv ntawm cov yeeb nkab phab ntsa
Kev soj ntsuam microscopic qhia tias cov phab ntsa ntawm cov yeeb nkab polyethylene tsis yog homogeneous nkaus xwb, tab sis yog tsim los ntawm micro- theem kev faib tawm hauv cheeb tsam. Los ntawm kev tswj cov txheej txheem ua haujlwm (xws li extrusion kub thiab txias tus nqi), manufacturers tuaj yeem kho cov crystallinity thiab orientation ntawm cov yeeb nkab phab ntsa. Piv txwv li, siab - cov txheej txheem ncab cov txheej txheem tuaj yeem taw qhia cov saw hlau molecular axially, yog li txhim kho lub voj voog tensile lub zog ntawm cov yeeb nkab.
Nws yog ib qho tsim nyog sau cia tias ib puag ncig kev ntxhov siab tawg (ESCR) tsis kam ntawm cov kav dej polyethylene yog ze rau kev tswj hwm ntawm nws cov microscopic defects. Lub xub ntiag ntawm grain ciam tsis muaj zog los yog oxidative degradation cheeb tsam thaum lub sij hawm tsim khoom yuav ua rau tawg ntawm cov yeeb nkab nyob rau hauv ntev -lub sij hawm siab los yog tshuaj corrosion. Yog li ntawd, siab - zoo PE kav feem ntau suav nrog me me ntawm antioxidants thiab carbon dub (piv txwv li, 2% -3% concentration) rau ob qho tib si tiv thaiv ultraviolet hluav taws xob thiab ncua kev laus, thiab tiv thaiv kev tawg tawm los ntawm cov pa roj carbon dub tsis sib xws.
III. Macroscopic Interlayer Structure Design
Cov kav dej polyethylene niaj hnub no feem ntau yog ntau- cov txheej txheem sib xyaw kom tau raws li qhov xav tau ntawm cov ntawv thov sib txawv. Ib txheej peb - txheej txheej muaj xws li:
1. Cov txheej txheej sab hauv: ncaj qha rau hauv kev sib cuag nrog cov khoom thauj nruab nrab, yuav tsum tau ua kom muaj kev sib tw siab (kom txo cov dej tsis kam) thiab tshuaj lom neeg. Qee cov kav dej suav nrog cov kab mob antibacterial masterbatch nyob rau hauv cov txheej txheem no los tiv thaiv kab mob loj hlob.
2. Cov txheej txheem nruab nrab (yeem): Siv los txhim kho kev ua tau zoo tag nrho ntawm cov yeeb nkab, xws li los ntawm kev ntxiv iav fiber ntau los yog nanofillers los txhim kho rigidity, los yog embedded hlau cables rau electromagnetic shielding.
3. Txheej txheej: tsom rau kev tiv thaiv, feem ntau muaj cov pa roj carbon dub ntau dua (UV resistant) thiab cov khoom hloov pauv (xws li ethylene-vinyl acetate copolymer EVA) los tiv thaiv kev puas tsuaj los ntawm kev sib haum xeeb hauv av lossis kev cuam tshuam sab nraud.
Rau loj - txoj kab uas hla polyethylene kav (piv txwv li, DN600 thiab saum toj no), ib tug "corrugated yeeb nkab" qauv kuj yuav siv tau -ua kom yooj ntawm cov yeeb nkab phab ntsa los ntawm lub sij hawm concave- convex duab, txo cov khoom siv thaum tuav lub siab.
IV. Engineering Adaptability of Connection Structures Cov kev sib txuas ntawm cov kav dej polyethylene (xws li pob tw fusion thiab electrofusion socket) muaj kev cuam tshuam rau lawv cov qauv tsim. Thermofusion bonding cia siab rau qhov re- diffusion ntawm cov saw hlau molecular ntawm cov yeeb nkab kawg ntawm lub ntsej muag ntawm qhov kub thiab txias, yog li xav tau cov khoom siv raw nrog thermal stability zoo thiab kev ua haujlwm fluidity. Electrofusion fittings muaj embedded kuj nyob ntawm tej; Thaum lub zog muaj zog, qhov chaw sib cuag ntawm cov yeeb nkab thiab qhov sib txuas yog hauv zos melted, tsim ib lub foob mus tas li. Lub tswv yim tsim "tus qauv ua haujlwm" no tshem tawm qhov xav tau rau kev sib khi rings hauv cov kav hlau ib txwm muaj, txo qhov kev pheej hmoo ntawm kev xau.
Cov qauv ntawm cov kav dej polyethylene yog lub luag haujlwm tseem ceeb ntawm lawv qhov kev ua tau zoo-los ntawm kev sib txuas ntawm cov saw hlau molecular mus rau macroscopic multi- txheej txheej tsim, txhua qhov kev nthuav dav ua haujlwm sib npaug ntawm kev ua haujlwm, kev nyab xeeb, thiab kev lag luam. Nrog rau kev nce qib hauv cov ntaub ntawv tshawb fawb, cov qauv ntawm cov kav dej polyethylene yav tom ntej yuav ua kom zoo dua qub, piv txwv li, los ntawm kev txhim kho lub zog - mus rau - qhov hnyav piv los ntawm nanocomposite thev naus laus zis lossis txhim kho tus kheej - kho cov txheej txheem ua haujlwm kom ntev kev pab cuam lub neej. Kev nkag siab txog cov qauv txheej txheem no tsis yog lub hauv paus rau kev xaiv engineering nkaus xwb tab sis kuj yog lub hauv paus tseem ceeb rau kev tsav tsheb tshiab hauv kev siv tshuab raj.
