Extruded polyethylene tuav nws cov qauv kev ncaj ncees thaum raug cov kua qaub, cov hauv paus, cawv, thiab cov kuab tshuaj organic feem ntau los ntawm nws cov qauv tsis yog -polar molecular. Cov tshuaj inertness no tshwm sim los ntawm polymer cov pa roj carbon yooj yim -hydrogen qaum, uas tsis muaj cov chaw reactive uas cov tshuaj aggressive feem ntau tawm tsam.
Cov txheej txheem tiv thaiv polymer ua haujlwm txawv dua li qhov koj xav tau. Ntau dua li tsim cov kev tiv thaiv kev tiv thaiv lossis kev cuam tshuam kev hem thawj, polyethylene tsuas yog tsis muaj dab tsi rau feem ntau cov tshuaj los cuam tshuam nrog. Nws ntev chains ntawm carbon atoms bonded rau hydrogen tsim ib tug molecular qauv yog li chemically ruaj khov uas muaj zog acids thiab bases hla nws yam tsis muaj txiaj ntsig.
Lub Molecular Foundation ntawm Extruded Polyethylene's Chemical Resistance
Extruded polyethylene chemical resistance originates nyob rau hauv nws cov qauv tsim: rov qab units ntawm ethylene (C₂H₄) polymerized rau hauv ntev hydrocarbon chains. Feem ntau LDPE, MDPE, thiab HDPE qib muaj cov tshuaj tiv thaiv zoo heev, txhais tau tias lawv tsis raug tawm tsam los ntawm cov kua qaub lossis cov hauv paus muaj zog thiab tiv taus cov oxidants maj mam thiab txo cov neeg ua haujlwm.
Qhov tsis muaj cov pab pawg polar functional piav qhov kev ruaj ntseg zoo kawg li. Tsis zoo li cov polymers nrog ester linkages, amide bonds, los yog hydroxyl pawg, polyethylene nthuav tawm ib tug ntshiab hydrocarbon nto. Polyethylene (LDPE thiab HDPE) yog sib xws nrog cov tshuaj feem ntau thiab tuaj yeem tiv taus cov kua qaub, cov hauv paus, txo cov neeg ua haujlwm, thiab maj mam oxidants. Kev tawm tsam tshuaj lom neeg yuav tsum muaj qhov chaw reactive, thiab polyethylene cov qauv yooj yim muab tsawg kawg nkaus.
Crystallinity amplifies this inherent resistance. The polymer exists as a semi-crystalline material where ordered crystalline regions alternate with disordered amorphous zones. HDPE is more rigid due to high crystallinity (>90%), thiab qhia toughness ntawm tsawg kub. Crystalline domains ntim nruj txaus uas feem ntau cov tshuaj molecules tsis tuaj yeem nkag mus, thaum lub cheeb tsam amorphous, txawm tias siv tau ntau dua, tseem tiv thaiv kev tawm tsam vim tsis yog -polar xwm ntawm cov chains.
Kev sib txawv ntom ntom ntawm cov qib polyethylene qhia txog qib sib txawv ntawm cov ceg thiab crystallinity. High-density polyethylene (HDPE) nta me me branching thiab crystallinity tshaj 60-80%, tsim kom muaj ib tug denser, ntau impermeable qauv. Tsawg-density polyethylene (LDPE) muaj ntau ceg ntsiab lus thiab qhia tau hais tias crystallinity nyob ib ncig ntawm 50-60%, muab cov tshuaj sib txawv me ntsis cov yam ntxwv ntawm qhov kub siab.
Pawg tshuaj tiv thaiv kev ua tau zoo
Immune Class: Comprehensive Resistance
PE tseem zoo li tsis cuam tshuam los ntawm cov kua qaub, cov hauv paus, cawv, thiab cov kuab tshuaj organic feem ntau, ua rau nws zoo tagnrho rau kev siv tshuaj lom neeg, thiab qhov kev tiv thaiv no txuas mus rau cov tshuaj ua liaj ua teb thiab cov neeg ua haujlwm tu.
Acids thoob plaws pH spectrum qhia tau tias muaj kev cuam tshuam tsawg kawg nkaus nrog polyethylene. Concentrated sulfuric acid, hydrochloric acid ntawm ntau yam concentrations, thiab phosphoric acid tuav polyethylene kev ncaj ncees ntawm chav tsev kub. Lub polymer tsis muaj qhov chaw yooj yim tiv thaiv protonation, thaum tsis muaj cov pab pawg oxidized yooj yim thaiv cov kua qaub-catalyzed degradation.
Bases zoo sib xws tsis tuaj yeem tawm tsam cov qauv. Sodium hydroxide daws, poov tshuaj hydroxide, thiab ammonium hydroxide ntawm high concentrations hu rau polyethylene yam tsis ua o, tawg, los yog poob ntawm txhua yam khoom. Qhov tsis muaj acidic hydrogen atoms lossis ester linkages tshem tawm cov txheej txheem tseem ceeb los ntawm cov hauv paus feem ntau degrade polymers.
Cawv los ntawm methanol los ntawm ntau dua molecular hnyav variants qhia tau zoo heev compatibility. Cov kuab tshuaj tiv thaiv kab mob no, uas nkag siab ntau yam khoom siv yas, cuam tshuam tsawg kawg nkaus nrog polyethylene tsis yog -polar nto. Qhov kev tiv thaiv no txuas mus rau glycols thiab polyols feem ntau ntsib hauv kev lag luam.
Thaj Chaw Uas Tsis Muaj Teeb Meem: Cov Kab Mob o thiab Plasticizers
Tsis yog tag nrho cov tshuaj raug tso tawm polyethylene tsis cuam tshuam. Qee cov kuab tshuaj organic cuam tshuam nrog cov polymer los ntawm lub cev tsis yog tshuaj lom neeg. Qee hom tshuaj yog absorbed rau ntau qib los ntawm polyethylene ua rau o, hnyav -nce, softening thiab ib co poob ntawm yield zog, tab sis cov plasticizing cov ntaub ntawv no ua rau tsis muaj tshuaj degradation ntawm resin.
Aromatic hydrocarbons sawv cev rau cov chav kawm tseem ceeb tshaj plaws ntawm cov kab mob o. Benzene, toluene, thiab xylene nkag mus rau thaj tsam amorphous ntawm extruded polyethylene, ua rau muaj kev hloov pauv thiab hloov khoom vaj khoom tsev. Aromatic hydrocarbons zoo li benzene muaj zog plasticizing nyhuv, whereas lwm tus zoo li roj av muaj zog zog. Cov txheej txheem nqus dej tseem thim rov qab - tshem tawm cov kuab tshuaj tso cai rau cov polymer rov qab mus rau nws qhov qub qhov ntev nrog cov khoom qub.
Chlorinated cov kuab tshuaj zoo li methylene chloride thiab chloroform tsim cov teebmeem o zoo sib xws. Cov penetrants no diffuse mus rau hauv cheeb tsam amorphous, ua kom dawb ntim ntawm cov saw hlau polymer. Kev sib cuam tshuam tsis ua rau cov khoom siv tshuaj lom neeg tab sis ib ntus hloov kho cov khoom siv los ntawm kev hloov pauv lub cev.
Aliphatic hydrocarbons qhia tus cwj pwm nruab nrab nyob ntawm qhov hnyav molecular. Tsawg molecular hnyav alkanes tuaj yeem ua rau o me ntsis, thaum cov roj av hnyav dua cuam tshuam tsawg. Cov roj av thiab cov roj diesel ua rau muaj kev cuam tshuam me me uas sib txawv ntawm qhov kub thiab qhov ntev ntawm qhov raug.
Lub reversible xwm ntawm plasticization distinguishes nws los ntawm degradation. Qee cov plasticizers txaus ntshai yog tias lawv raug tshem tawm ntawm kev sib cuag nrog polyethylene, ib feem yuav "qhuav" tawm thiab rov qab mus rau nws qhov qub yam tsis muaj kev poob. Cov yam ntxwv no tso cai rau cov khoom siv polyethylene rov qab ua haujlwm tom qab cov kuab tshuaj raug tshem tawm, txawm hais tias qhov kev tsis sib haum xeeb ntawm kev sib cuag tuaj yeem txwv qee qhov kev siv.
Kev zam tshwj xeeb: Oxidizing Agents
Oxidizers yog tib pab pawg ntawm cov ntaub ntawv muaj peev xwm ntawm cov tshuaj degrading polyethylene. Tsis zoo li kev sib cuam tshuam ntawm lub cev ntawm cov o los yog tsis yog - kev cuam tshuam ntawm cov kua qaub thiab cov hauv paus, oxidizers pib cov tshuaj tiv thaiv tiag tiag uas hloov pauv cov qauv polymer mus tas li.
Muaj zog oxidizing cov neeg ua hauj lwm tawm tsam extruded polyethylene los ntawm cov dawb radical mechanisms. Lub zog oxidizers zoo li ozone lossis chlorine roj tuaj yeem ua rau oxidation thiab tawg ntawm cov saw hlau polymer dhau sijhawm, tshwj xeeb tshaj yog thaum raug kub hnyiab. Cov txheej txheem oxidation pib nrog hydrogen abstraction los ntawm cov pob txha polymer, tsim cov chaw radical uas propagate los ntawm saw scission thiab cross-txuas kev sib txuas.
Nitric acid nyob rau hauv high concentrations qhia no oxidative nres. Yas HDPE tuaj yeem tiv taus cov tshuaj oxidizing me me xws li hydrogen peroxide ntawm qhov tsis tshua muaj siab (hauv qab 30%) nrog me ntsis kom tsis muaj degradation, tab sis muaj zog oxidizers zoo li ozone lossis chlorine roj tuaj yeem ua rau cov saw hlau tawg. Kev sib xyaw ua ke ntawm acidity thiab oxidizing zog tsim cov xwm txheej uas polyethylene maj yellows, ua nkig, thiab poob txhua yam muaj zog.
Chlorinated dej nthuav tawm ib qho tseem ceeb oxidative ib puag ncig. Extruded polyethylene yog raug rau oxidative degradation thaum raug chlorinated dej, nrog txhua yam PE yeeb nkab tsis ua hauj lwm nyob ntawm cov khoom siv, siab, kub, pH dej, dawb muaj chlorine concentration, thiab lub sij hawm raug. Kev kho dej hauv nroog tsis tshua muaj qhov ua rau tsis ua haujlwm sai, tab sis qhov ntev - raug rau ntau xyoo tuaj yeem tsim kev puas tsuaj.
Permanganate daws, chromic acid, thiab muaj zog peroxide concentrations tag nrho pib zoo li oxidative degradation. Tus nqi nyob ntawm qhov concentration, kub, thiab qib polymer. HDPE's crystallinity siab dua muab qee qhov kev tiv thaiv los ntawm kev txwv oxidizer nkag mus rau thaj tsam saum npoo, thaum LDPE cov qauv qhib ntau tso cai rau nkag mus tob.
Kub raws li kev hloov pauv hloov
Kev ntsuas tshuaj tiv thaiv universally suav nrog qhov kub thiab txias vim tias thermal zog hloov pauv kev sib cuam tshuam kinetics. Cov kab kos kab lis kev cai feem ntau qhia txog tus cwj pwm ntawm 70℃F (21 degree) thiab 140℃F (60 degree), qhia txog qhov ntsuas kub ntawm qhov ua tau zoo rau feem ntau cov ntawv siv polyethylene.
Kev ua haujlwm kub ntawm cov kav dej HDPE feem ntau yog los ntawm -40℃F (-40 degree) txog 140℃F (60 degree), nrog thermal degradation thiab cov qauv poob pib tshwm sim dhau 140℃F rau tus qauv HDPE. Qhov kev txwv saum toj no tsis sawv cev rau qhov melting - HDPE melts ntawm 248-266℃F - tab sis qhov kub thiab txias qhov twg txhua yam khoom degrade thiab tshuaj tua kab mob nrawm.
Qhov kub nce nce molecular txav, tso cai rau cov tshuaj ntau dua qhov tob tob. Cov kuab tshuaj uas ua rau me me o ntawm chav tsev kub yuav ua rau muaj kev hloov pauv loj ntawm qhov kub siab. Cov kua qaub thiab cov hauv paus uas tsis pom qhov ua rau txias tuaj yeem pib tawm tsam ntawm qhov kub thiab txias. Qee cov tshuaj tiv thaiv nrog PE sib txawv ntawm qhov sib txawv ntawm qhov kub thiab txias, nrog rau cov cua kub ntau dua tuaj yeem ua kom nrawm dua.
Oxidation tus nqi ua raws li Arrhenius kinetics, kwv yees li ob npaug rau txhua 10℃nce. Chlorinated dej uas yuav siv sij hawm ntau xyoo los degrade polyethylene ntawm chav tsev kub tuaj yeem ua rau tsis ua hauj lwm hauv lub hlis ntawm 60 degree. Qhov kev cia siab ntawm qhov ntsuas kub no piav qhia txog vim li cas cov kav dej kub tau hais txog tus ntoo khaub lig- txuas polyethylene (PEX) es tsis yog HDPE tus qauv.
Mechanical stress compounds thermal teebmeem los ntawm ib puag ncig kev ntxhov siab tawg. Cheebtsam nyob rau hauv tas li load qhia txo cov tshuaj tiv thaiv piv rau unstressed kuaj. Kev sib xyaw ua ke ntawm tensile stress, siab kub, thiab marginal tshuaj compatibility tsim tej yam kev mob rau ceev tsis ua hauj lwm.
Yuav ua li cas Extruded Polyethylene Hands Industrial Chemical Exposure
Inorganic compounds
Extruded polyethylene tuav feem ntau inorganic ntsev nrog kev ruaj ntseg tshwj xeeb. Sodium chloride, calcium chloride, aluminium sulfate, thiab ammonium nitrate cov kev daws teeb meem ntawm txhua qhov concentration qhia tsis muaj kev cuam tshuam. HDPE feem ntau yog siv rau hauv kev tswj cov khib nyiab ua liaj ua teb vim nws cov tshuaj lom neeg ruaj khov thiab tiv thaiv corrosion, zoo tuav cov khoom pov tseg thaum tiv thaiv ib puag ncig.
Hlau hydroxides los ntawm lithium los ntawm cesium ua kom pom kev sib haum xeeb. Cov kev daws teeb meem yooj yim no, uas tawm tsam ntau yam khoom siv engineering, tawm hauv polyethylene tsis cuam tshuam. Txiv qaub slurries, caustic soda ntawm kev lag luam ntau, thiab cov tshuaj potassium hydroxide tuaj yeem khaws cia tsis tu ncua.
Halogen ntsev suav nrog sodium hypochlorite (bleach) ntawm cov concentrations raug pom zoo siv tau, txawm tias kev ua tau zoo nyob ntawm kev tsim. OR-1000 qhov system tswj nws cov elongation zog nyob rau lub sijhawm thaum muaj cov tshuaj oxidizing hnyav xws li sodium hypochlorite, nrog kev ua tau zoo dua lwm cov ntaub ntawv HDPE. Standard HDPE qib tiv thaiv tsev neeg cov tshuaj bleach concentrations, thaum tshwj xeeb formulations lis industrial-zog oxidizers.
Organic Chemical nyob rau hauv Manufacturing
HDPE qhov kev tiv thaiv rau cov tshuaj ua rau nws tsim nyog rau kev xa cov chiv thiab tshuaj tua kab los ntawm cov txheej txheem fertigation, uas muab cov dej thiab fertilization rau hauv ib txheej txheem. Fertilizer tov uas muaj urea, ammonium nitrate, thiab phosphates qhia tau hais tias tag nrho compatibility nyob rau hauv concentration ntau yam.
Cov tshuaj tua kab sib txawv hauv cov tshuaj muaj pes tsawg leeg, tab sis feem ntau pom tau tias muaj kev sib raug zoo nrog polyethylene. Cov khoom xyaw nquag yaj hauv dej lossis roj cov nqa khoom feem ntau tsis tawm tsam cov qauv polymer. Emulsifiers thiab surfactants siv nyob rau hauv kev ua liaj ua teb formulations tej zaum yuav ua rau me ntsis rau saum npoo yam tsis muaj tej yam khoom hloov pauv.
Cov khoom siv roj av los ntawm cov roj av los ntawm cov roj hnyav hnyav ua rau cov teebmeem plasticization tau tham ua ntej. Biodiesel thiab cov pa roj diesel yog absorbed los ntawm amorphous theem ntawm semi-crystalline HDPE thiab induce ib tug plasticization nyhuv uas hloov molecular mus thiab yielding zog. Roj cia yuav tsum xav txog qhov o thiab permeation, tshwj xeeb tshaj yog rau cov feem sib dua.
Cov tshuaj ntxuav tu muaj kev sib xyaw ua ke. Alkaline cleaners, detergents, thiab surfactant daws feem ntau ua haujlwm zoo. Cov kuab tshuaj-raws li cov tshuaj ntxuav tes uas muaj cov tshuaj tsw qab lossis cov tshuaj chlorinated yuav tsum tau kuaj xyuas. Quaternary ammonium tebchaw siv los ua cov tshuaj tua kab mob qhia tau hais tias muaj kev sib raug zoo thoob plaws ntau qhov sib txawv.
Kev Tiv Thaiv Kev Tiv Thaiv Ntau Txoj Kev Tawm Tsam
Kev raug tshuaj lom neeg tshwm sim los ntawm txoj hauv kev sib txawv, txhua qhov kev sib tw ntawm cov khoom siv sib txawv. Immersion sawv cev rau qhov mob hnyav tshaj plaws, nrog rau kev sib cuag tshuaj lom neeg thoob plaws tag nrho saum npoo hauv qab hydrostatic siab yuam kev nkag mus. Kev ntsuas tshuaj tiv thaiv feem ntau suav nrog cov qauv kuaj yas rau hauv 60 hnub hauv cov tshuaj ntsuam xyuas yam tsis muaj kev ntxhov siab, nrog cov khoom tensile ntsuas ua ntej thiab tom qab raug.
Splash thiab tshuaj tsuag kev sib cuag tsim kev sib tshuam nrog lub sijhawm ziab ntawm cov xwm txheej. Qhov kev caij tsheb kauj vab no tuaj yeem ntxhov siab cov ntaub ntawv sib txawv dua li qhov kev tso dej tas li, tshwj xeeb tshaj yog rau cov kuab tshuaj tsis muaj zog uas evaporate tawm cov khoom seem. Polyethylene tuav cov xwm txheej txaws zoo vim tias nws cov tshuaj tiv thaiv tsis nyob ntawm qhov chaw txias lossis cov txheej tiv thaiv.
Vapor raug cuam tshuam rau polyethylene tsawg kawg nkaus rau cov tshuaj feem ntau. Lub polymer impermeability rau dej vapor txuas mus rau ntau cov organic vapors, txawm tias cov kuab tshuaj tsw qab tuaj yeem nkag mus qeeb. Muaj qhov cua feem ntau tswj cov vapor concentrations hauv qab theem ua rau muaj kev nqus txaus.
Phab ntsa thickness cuam tshuam los ntawm kev diffusion ntev. Thicker Cheebtsam tiv thaiv permeation ntev, tab sis lawv kuj siv sij hawm ntev dua los desorb absorbed tshuaj. Thickness, kev ntxhov siab, thiab kev ua haujlwm yog qhov cuam tshuam rau cov resin qhov kawg ua haujlwm, yog li ntawd tib txoj hauv kev los kwv yees qhov kawg khoom tsis kam yog simulating qhov tseeb.
Qib Xaiv rau Chemical Ib puag ncig
Kev xaiv ntawm LDPE, MDPE, thiab HDPE nyob ntawm kev ntsuas tshuaj tiv thaiv nrog cov khoom siv tshuab. HDPE paub txog nws lub zog siab- rau- qhov sib piv ceev, nrog qhov ceev ntawm 930 txog 970 kg / m³, muaj zog intermolecular rog thiab tensile zog (38 MPa) piv rau LDPE (21 MPa).
HDPE muab cov tshuaj tiv thaiv siab tshaj plaws los ntawm nws cov crystallinity siab thiab ntom. Cov qauv nruj nruj txwv tsis pub nkag mus rau tshuaj lom neeg thiab muab kev tiv thaiv zoo tshaj plaws rau kev ntxhov siab ib puag ncig. Cov ntawv thov uas muaj cov tshuaj hnyav, qhov kub thiab txias, lossis kev ntxhov siab txhua yam nyiam HDPE.
LDPE muaj qhov zoo uas qhov kev hloov pauv tseem ceeb tshaj qhov kev tiv thaiv siab tshaj plaws. Nws qis crystallinity tso cai rau ntau dua elongation thiab cuam tshuam tsis kam ntawm qhov kub thiab txias. LDPE yog ib txwm hloov tau yooj yim yam tsis muaj qhov sib ntxiv ntawm plasticizers thiab melts ntawm qhov kub tsis tshua muaj (85 degree), thaum cov tshuaj tsis muaj zog nrog cov tshuaj oxidizing muaj zog thaum kawg ua rau oxidation thiab embrittlement.
MDPE nyob hauv nruab nrab hauv av, sib txuas nruab nrab crystallinity nrog cov khoom sib npaug. Nws muab kev ntxhov siab tawg zoo dua li HDPE thaum muab cov tshuaj tiv thaiv zoo dua piv rau LDPE. MDPE muaj kev poob siab zoo thiab kev poob siab tsis kam thiab tsis tshua muaj nqis -rhiab dua HDPE, nrog kev ntxhov siab zoo dua - cracking resistance.
Hla -txuas polyethylene (PEX) txuas kev ua haujlwm rau hauv cov txheej txheem kub dua. PEX yog tsim los ntawm crosslinking HDPE los yog LDPE los txhim kho cov cua sov thiab tshuaj tiv thaiv, nrog kev txhim kho qhov kub thiab txias siv hauv cov kav dej rau cov dej kub thiab dej txias. Tus ntoo khaub lig-txuas txheej txheem tsim cov tshuaj sib txuas ntawm cov saw hlau polymer, tiv thaiv kev ntws ntawm qhov kub siab thaum tswj cov tshuaj tiv thaiv.
Tiag -Kev ua tau zoo hauv ntiaj teb hauv kev thov thov
Agricultural Chemical Handling
Cov kav dej HDPE tiv taus ntau yam tshuaj xws li tshuaj chiv, tshuaj tua kab, thiab lwm yam tshuaj ua liaj ua teb uas tuaj yeem ua rau muaj kev puas tsuaj rau ntau hom yeeb nkab. Fertilizer spreaders, cov cuab yeej tshuaj tsuag, thiab cov tshuaj cia tso tsheb hlau luam cia siab rau polyethylene lub peev xwm los daws cov corrosive sib tov.
Anhydrous ammonia, ib qho ntawm kev ua liaj ua teb cov tshuaj nyuaj tshaj plaws, yuav tsum muaj cov ntaub ntawv tshwj xeeb. Thaum polyethylene qhia tau hais tias zoo sib xws, daim ntawv thov cov ntsiab lus tseem ceeb. Pressurized cia ntawm qhov kub tsis tshua muaj kev ntxhov siab rau cov polymer txawv dua li cov kev daws teeb meem ambient. Gaskets, fittings, thiab cov ntsiab lus kev ntxhov siab xav tau kev saib xyuas tshwj xeeb.
Herbicide formulations uas muaj 2,4-D, glyphosate, thiab dicamba ua tau zoo heev compatibility. Cov khoom xyaw nquag no hauv ntau cov cab kuj tsis tshua tawm tsam polyethylene. Cia tso tsheb hlau luam los ntawm 50 nkas loos mus rau ntau txhiab nkas loos siv rotationally molded polyethylene siv.
Industrial Chemical Cia
HDPE tso tsheb hlau luam thiab ntim khoom siv dav siv los khaws cov tshuaj lom neeg vim tias lawv cov tshuaj tiv thaiv zoo heev thiab impermeability. Cov ntaub ntawv khaws cia ntau dhau los ntawm polyethylene kev sib xyaw ua ke ntawm kev tiv thaiv, tus nqi -kev ua tau zoo, thiab kev ua tau zoo.
Acid cia los ntawm sulfuric los ntawm hydrochloric nyob rau hauv industrial concentrations cia siab rau polyethylene stability. HDPE's non-polar molecular muaj pes tsawg leeg tiv thaiv cov tshuaj feem ntau los ntawm kev nkag mus rau hauv cov khoom, nrog rau cov qauv crystalline (xws li ntawm 60% mus rau 80%) txhawb zog thiab ruaj khov rau kev ua tau zoo nyob rau hauv cov xwm txheej nyuaj. Kev txiav txim siab kub ua qhov tseem ceeb rau cov kua qaub uas muaj zog uas exothermic dilution tuaj yeem nce qhov kub.
Cov tshuaj Caustic suav nrog sodium hydroxide ntawm 50% concentration thiab potassium hydroxide nrhiav tau ntev - lub sij hawm cia hauv cov hlab ntsha polyethylene. Lub polymer qhov kev tiv thaiv tshem tawm kev txhawj xeeb txog lub hauv paus-catalyzed ester hydrolysis uas txwv ntau yam yas yas.
Cov tshuaj kho dej muaj ntau yam kev sib tw sib tw. Calcium hypochlorite, ferric chloride, thiab alum solutions tag nrho qhia tau zoo sib xws nrog cov qib polyethylene tsim nyog. OR-1000 engineered resin system muab plaub zaug lub zog antioxidant ntawm cov qauv tank phab ntsa rau superior ib puag ncig kev nyuaj siab tawg tsis kam nyob rau hauv oxidizing daim ntaub ntawv.
Cov Khoom Siv Ua Haujlwm
Extruded polyethylene Cheebtsam ua haujlwm nyob rau hauv cov cuab yeej raug rau kev sib cuag tshuaj lom neeg tsis tu ncua. Cov txheej txheem tuav cov khoom tau txais txiaj ntsig los ntawm extruded polyethylene cov yam ntxwv ntawm cov khoom thiab cov yam ntxwv saum npoo, nrog cov khoom siv conveyor, chutes, thiab cov lus qhia xav tau cov ntaub ntawv uas muab cov khoom lag luam du thaum tiv thaiv hnav thiab tshuaj tua kab mob.
Cov twj tso kua mis, lub cev lub cev, thiab cov kav dej siv cov polyethylene qhov twg hlau corrosion ua teeb meem. Kev sib xyaw ntawm cov tshuaj tiv thaiv thiab kev cuam tshuam lub zog tswj cov txheej txheem kev ntxhov siab yam tsis muaj kev puas tsuaj loj. HDPE feem ntau yog siv rau cov tshuaj tso tsheb hlau luam, cov kav dej flanges, kev tsim kho hauv hiav txwv, thiab ntau lwm yam kev siv uas yuav tsum tau muaj tshuaj lom neeg.
Cov ntawv thov ua zaub mov siv nyiaj rau polyethylene's FDA ua raws nrog rau tshuaj lom neeg. Khoom noj khoom haus- daim ntawv thov kev nyab xeeb siv PE lub peev xwm ua raws li FDA rau cov khoom lag luam uas xav tau kev sib cuag cov zaub mov ncaj qha, nrog rau cov khoom siv ua khoom siv thiab cov thawv ntim khoom hauv cov chaw tsim khoom noj uas tau txais kev nyab xeeb nruj. Kev ntxuav cov tshuaj tiv thaiv ua kom cov cuab yeej muaj sia nyob rov ua kom huv huv.
Kev txwv thiab hom kev ua tsis tiav
Kev nkag siab qhov twg polyethylene tsis ua pov thawj tseem ceeb npaum li kev paub qhov twg nws ua tiav. PE yog recalcitrant heev thiab inert, tab sis LDPE tuaj yeem maj mam tawm tsam los ntawm cov tshuaj oxidizing muaj zog thiab qee cov kuab tshuaj, ua rau softening lossis o. Paub txog cov cim ceeb toom ntxov tiv thaiv kev puas tsuaj loj.
Discoloration signals pib degradation. Polyethylene raug oxidizers maj mam yellows, nce mus rau xim av raws li carbonyl pawg. Cov xim hloov pauv qhia txog kev tawm tsam tshuaj lom neeg uas yuav tsum tau kho kom raug. UV raug ua ke nrog cov tshuaj oxidizing accelerates tus txheej txheem no.
Nto crazing tshwm zoo li cov kab nrib pleb pom nyob rau hauv magnification. Environmental stress cracking tshwm sim los ntawm kev sib xyaw ntawm tensile stress thiab marginal chemical compatibility. Crazes propagate maj mam tab sis nws thiaj li ua rau txhua yam tsis ua haujlwm. Yog tias LDPE cov khoom siv labware tau hloov pauv mus tas li, lossis yog cov kab nrib pleb lossis kab laug sab -zoo li "crazing" pib tshwm sim, nws yog lub sijhawm los hloov cov labware qub.
Embrittlement manifests li poob ntawm kev cuam tshuam tsis kam thiab elongation. Polyethylene uas ib zaug deformed plastically pib fracturing nyob rau hauv nkig hom. Qhov kev hloov pauv no qhia txog kev sib tsoo ntawm cov oxidative degradation los yog hla - txuas los ntawm hluav taws xob lossis cov tshuaj tshwj xeeb.
Dimensional instability los ntawm o los yog permeation cuam tshuam rau precision daim ntaub ntawv. Cov khoom uas raug rau cov kuab tshuaj plasticizing tuaj yeem loj hlob dhau qhov kev txwv. Roj permeation los ntawm polyethylene tso tsheb hlau luam, txawm tias qeeb, yuav tsum tau xav txog nyob rau hauv kaw kaw kaw lus tsim.
Cov lus nug nquag
Dab tsi tshuaj tua polyethylene aggressively?
Oxidizers yog tib pab pawg ntawm cov ntaub ntawv muaj peev xwm ntawm cov tshuaj degrading polyethylene. Muaj zog oxidizing cov neeg ua haujlwm zoo li concentrated nitric acid, ozone, chlorine gas, thiab muaj zog permanganate daws tawm tsam los ntawm cov dawb radical mechanisms. Cov tshuaj no rhuav tshem cov saw hlau polymer ntau dua li tsuas yog o los yog plasticizing cov khoom. Qhov kub thiab txias muaj feem cuam tshuam rau kev tawm tsam, nrog rau qhov kub siab ua kom oxidative degradation.
Polyethylene puas tuaj yeem siv roj av thiab roj cia?
Polyethylene qhia qhov sib txawv ntawm cov roj av. Ob qho tib si biodiesel thiab cov pa roj diesel yog absorbed los ntawm amorphous theem ntawm semi-crystalline HDPE thiab induce ib tug plasticization nyhuv uas hloov cov molecular mus. Cov roj ua rau o thiab qee yam khoom hloov pauv yam tsis muaj tshuaj lom neeg degradation. Cov roj tshwj xeeb- cov qib polyethylene suav nrog cov khoom siv ntxiv kom txo qis permeation thiab tswj qhov ruaj khov. Daim ntawv thov yuav tsum suav rau thermal expansion thiab permeation tus nqi.
Puas yog qhov kub thiab txias cuam tshuam cov tshuaj tiv thaiv zoo heev?
Qhov kub thiab txias cuam tshuam rau kev ua haujlwm tsis zoo. Kev ua haujlwm kub ntau rau HDPE kav txuas ntawm -40℃F mus rau 140℃F, nrog thermal degradation thiab cov qauv poob pib dhau 140℃F rau tus qauv HDPE. Tshuaj tua tus nqi kwv yees li ob npaug rau txhua txhua 10℃nce. Cov tshuaj uas qhia txog kev sib raug zoo ntawm chav tsev kub yuav ua rau muaj teeb meem ntawm qhov kub siab. Nco ntsoov txheeb xyuas qhov sib haum xeeb ntawm qhov ntsuas kub ua haujlwm tiag tiag es tsis yog siv cov ntaub ntawv ntsuas kub hauv chav tsev.
Ntev npaum li cas polyethylene tiv taus tshuaj lom neeg?
Polyethylene muab ntau xyoo ntawm kev pabcuam hauv cov khoom siv tshuaj lom neeg. Kev ntsuas tshuaj tiv thaiv tus qauv suav nrog immersing cov qauv yas rau 60 hnub hauv cov tshuaj ntsuam xyuas, tom qab ntawd ntsuas cov khoom tensile. Tiag -kev ua tau zoo hauv ntiaj teb txuas ntxiv mus dhau lub sijhawm sim thaum cov xwm txheej poob rau hauv kev txwv kev sib raug zoo. Txawm li cas los xij, oxidizing chemicals thiab marginal compatibilities qhia lub sij hawm - nyob ntawm degradation. Cov ntawv thov uas xav tau ntau- xyoo caum lub neej yuav tsum suav nrog cov xwm txheej kev nyab xeeb thiab kev tshuaj xyuas ib ntus.
Extruded polyethylene cov tshuaj tiv thaiv stems los ntawm lub hauv paus molecular simplicity es tsis engineered complexity. Lub polymer tsis yog -polar hydrocarbon qauv tsuas yog muaj ob peb qhov chaw tshuaj tiv thaiv rau feem ntau cov tshuaj los tua. Qhov kev tiv thaiv tsis zoo no, ua ke nrog ib nrab -crystalline impermeability, tsim kev ua tau zoo uas ntsuas los ntawm lub chaw soj nstuam mus rau kev lag luam tshuaj.
Cov tswv yim txwv tseem ceeb npaum li qhov muaj peev xwm. Oxidizing cov neeg ua haujlwm rhuav tshem cov qauv ntawm inertness, thaum o los ntawm qee cov kuab tshuaj cuam tshuam rau qhov ruaj khov. Kub hloov pauv txhua qhov kev sib cuam tshuam, ua rau kev tiv thaiv tsis muaj zog es tsis yog cov khoom zoo li qub.
Xaiv cov polyethylene rau kev pabcuam tshuaj lom neeg yuav tsum tau ua raws qib cov yam ntxwv rau cov xwm txheej raug. HDPE's crystallinity maximizes tsis kam rau qhov hnyav ib puag ncig, thaum LDPE qhov yooj yim haum rau nruab nrab qhov yuav tsum tau muaj kev cuam tshuam. Kev nkag siab txog ob qho tib si muaj peev xwm thiab cov kev txwv ua rau polyethylene pab kev ntseeg siab thoob plaws kev lag luam los ntawm kev ua liaj ua teb los ntawm kev ua tshuaj.
Ntsiab Cai
Polyethylene tiv taus cov kua qaub, cov hauv paus, thiab cov kuab tshuaj feem ntau los ntawm nws cov qauv tsis yog -polar molecular uas tsis muaj qhov chaw reactive
Oxidizers yog tib pab pawg muaj peev xwm ntawm cov tshuaj degrading polyethylene, tawm tsam los ntawm cov dawb radical mechanisms.
Aromatic hydrocarbons thiab chlorinated kuab tshuaj ua rau reversible o es tsis muaj tshuaj degradation
Thermal degradation pib tshaj 140℃F rau tus qauv HDPE, ua rau kub qhov tseem ceeb kuj tseem ceeb
HDPE lub siab crystallinity muab cov tshuaj tiv thaiv zoo dua piv rau LDPE cov qauv qhib ntau dua