Compatibilizers tau ua pov thawj zoo hauv kev txhim kho cov khoom tseem ceeb xws li qhov cuam tshuam / qhov sib npaug ntawm PCR thiab PIR sib xyaw ntawm polyolefins thiab lwm yam yas.#sustainable kev loj hlob
Rov ua dua HDPE / PP qauv yam tsis muaj Dow Engage compatibilizer (sab saum toj) thiab Recycled HDPE / PP qauv nrog Engage POE compatibilizer.Compatibility tripled elongation ntawm so ntawm 130% mus rau 450%.(Duab: Dow Chemical)
Raws li cov yas rov ua dua tshiab dhau los ua kev lag luam loj hlob thoob ntiaj teb, cov khoom siv tau zoo thiab cov khoom siv ntxiv tau siv los daws cov teeb meem hybrid resin hauv thaj chaw xws li ntim khoom thiab cov khoom siv, kev tsim kho, kev ua liaj ua teb thiab tsheb.Kev txhim kho cov khoom ua tau zoo, txhim kho kev ua haujlwm thiab txo cov nqi thiab kev cuam tshuam ib puag ncig yog ib qho ntawm cov teeb meem tseem ceeb, nrog cov neeg siv khoom tseem ceeb xws li polyolefins thiab PET ua txoj hauv kev.
Ib qho kev txwv loj rau kev siv cov khoom siv rov ua dua tshiab yog qhov siv nyiaj ntau thiab siv sij hawm sib cais ntawm cov yas tsis sib xws.Los ntawm kev tso cai rau cov plastics tsis sib xws kom yaj-kib, cov khoom sib xyaw ua ke pab txo qhov kev xav tau ntawm kev sib cais thiab ua kom cov neeg tsim khoom tsim cov khoom lag luam zoo dua, thaum tib lub sij hawm nce cov ntsiab lus rov ua dua tshiab thiab nkag mus rau cov khoom tsis zoo thiab cov nqi qis dua.
Cov recyclable compatibilizers muaj xws li tshwj xeeb polyolefin elastomers, styrenic block copolymers, tshuaj hloov kho polyolefins, thiab additives raws li titanium txhuas chemistry.Lwm qhov kev tsim kho tshiab kuj tau tshwm sim.Txhua tus yuav tsum tau ua lub hauv paus theem ntawm kev ua lag luam yav tom ntej.
Raws li Dow, Koom nrog POE thiab Infuse OBC yog qhov zoo tshaj plaws rau HDPE, LDPE thiab LLDPE compatibility nrog polypropylene vim PE qaum thiab alpha olefins ua comonomers.(Duab: Dow Chemical)
Tshwj xeeb polyolefin elastomers (POE) thiab polyolefin plastomers (POP), Ameslikas tau qhia los txhim kho cov khoom ntawm polyolefins xws li kev cuam tshuam thiab tensile lub zog, tau hloov zuj zus raws li compatibilizers rau recycled PE thiab PP, qee zaum kuj siv nrog lwm cov ntaub ntawv xws li PET lossis PET.nylon.
Cov khoom no suav nrog Dow's Engage POE, OBC-infused ethylene-alpha-olefin comonomer random copolymer, ib qho nyuaj-soft block alternating olefin copolymer, thiab Exxon Mobil Vistamaxx Propylene-Ethylene thiab Exact Ethylene-Octene POP.
Cov khoom no raug muag rau cov khoom siv rov ua dua tshiab / cov khoom sib xyaw thiab lwm cov khoom siv rov ua dua tshiab, hais tias Jesús Cortes, tus tsim lag luam ntawm ExxonMobil Product Solutions, ceeb toom tias kev sib raug zoo tuaj yeem yog ib qho cuab yeej los pab cov neeg siv khoom rov siv dua cov kab mob sib kis thiab muaj peev xwm txo tus nqi tseem ceeb rau cov kwj deg polyolefin.Han Zhang, Tus Thawj Coj ntawm Lub Ntiaj Teb Sustainability rau Ntim thiab Cov Khoom Tshwj Xeeb ntawm Lub Tuam Txhab Dow Chemical, tau hais tias: "Peb cov neeg siv khoom tau txais txiaj ntsig los ntawm kev tsim cov khoom lag luam zoo dua nrog kev nkag mus rau kev siv dav dav.Peb pab cov processors uas siv cov compatibilizers kom nce cov ntsiab lus rov ua dua thaum tswj kev tsim khoom. "
"Peb cov neeg siv khoom tau txais txiaj ntsig los ntawm kev tsim cov khoom lag luam zoo dua thaum muaj kev nkag mus rau cov kwj deg dav dua."
ExxonMobil 'Cortés tau lees paub tias tib qib Vistamaxx thiab cov qhab nia zoo tsim nyog rau kev hloov kho nkauj xwb kuj tuaj yeem siv los xyuas kom muaj kev sib raug zoo nrog cov khoom siv rov ua dua tshiab.Nws tau sau tseg tias Vistamaxx polymers ua HDPE, LDPE thiab LLDPE tau tshaj polypropylene, ntxiv tias vim yog cov polarity ntawm polymers xws li PET lossis nylon, Vistamaxx qib grafting yuav tsum tau ua kom polyolefins sib xws nrog cov polymers."Piv txwv li, peb tau ua hauj lwm nrog ntau lub compounders rau graft Vistamaxx los ua polyolefins sib xws nrog nylon thaum lub hom phiaj los tswj cov kev ua tau zoo uas Vistamaxx polymers tuaj yeem coj mus rau kev sib xyaw ua ke."
Rice.1 MFR daim ntawv qhia cov xim sib xyaw ntawm cov khoom siv rov ua dua HDPE thiab polypropylene nrog thiab tsis muaj Vistamaxx additive.(Qhov chaw: ExxonMobil)
Kev sib raug zoo tuaj yeem lees paub los ntawm kev txhim kho cov khoom siv kho tshuab, xws li kev xav tau kev cuam tshuam, raws li Cortez.Kev nce fluidity kuj tseem ceeb heev thaum rov siv cov ntaub ntawv.Ib qho piv txwv yog kev tsim cov tshuaj molding formulations rau HDPE lub raj mis ntws.Nws sau tseg tias txhua qhov tshwj xeeb elastomers muaj niaj hnub no muaj lawv siv."Lub hom phiaj ntawm kev sib tham tsis yog los sib piv lawv cov kev ua tau zoo tag nrho, tab sis xaiv cov cuab yeej zoo tshaj plaws rau ib txoj haujlwm tshwj xeeb."
Piv txwv li, nws hais tias, "Thaum PE sib haum nrog PP, peb ntseeg tias Vistamaxx muab cov txiaj ntsig zoo tshaj plaws.Tab sis kev ua lag luam kuj xav tau kev txhim kho kev tiv thaiv, thiab ethylene-octene plstomers yuav tsim nyog thaum tab tom nrhiav rau qhov kub thiab txias toughness. "
Cortez ntxiv, "Ethylene-octene plastomers zoo li peb Cov Qib Siab lossis Dow's Engage thiab Vistamaxx muaj cov qib zoo sib xws."
Dow's Zhang piav qhia tias thaum muaj polypropylene nyob rau hauv HDPE feem ntau nce nruj raws li ntsuas los ntawm flexural modulus, nws degrades zog raws li ntsuas los ntawm toughness thiab tensile elongation vim qhov incompatibility ntawm ob lub Cheebtsam.Kev siv cov compatibilizers nyob rau hauv cov HDPE / PP blends txhim kho qhov txhav / viscosity tshuav nyiaj li cas los ntawm kev txo cov theem sib cais thiab txhim kho interfacial adhesion.
Rice.2. Kev cuam tshuam lub zog daim duab qhia cov xim sib txawv ntawm cov khoom siv rov ua dua HDPE thiab polypropylene, nrog thiab tsis muaj Vistamaxx additive.(Qhov chaw: ExxonMobil)
Raws li Zhang, Koom nrog POE thiab Infuse OBC yog qhov zoo tshaj plaws los ua HDPE, LDPE thiab LLDPE tau tshaj polypropylene vim yog PE qaum thiab alpha-olefin comonomer.Raws li cov khoom siv ntxiv rau PE / PP blends, lawv feem ntau yog siv los ntawm 2% mus rau 5% los ntawm qhov hnyav.Zhang tau sau tseg tias los ntawm kev txhim kho qhov sib npaug ntawm hardness thiab toughness, Koom nrog POE compatibilizers xws li Qib 8100 tuaj yeem muab tus nqi ntau dua rau cov khoom siv rov ua dua tshiab PE / PP, suav nrog cov dej khib nyiab siab hauv PE thiab PP.Cov ntawv thov suav nrog kev txhaj tshuaj molded automotive qhov chaw, cov kaus poom xim, cov thoob khib nyiab, lub thawv ntim khoom, pallets thiab rooj tog zaum nraum zoov.
Kev ua lag luam xav tau kev txhim kho kev ua tau zoo thiab ethylene octene plastomers tuaj yeem ua lub luag haujlwm thaum qhov kub tsis tshua muaj kev cuam tshuam toughness.
Nws hais ntxiv: “Qhov ntxiv ntawm tsuas yog 3 wt.% Koom nrog 8100 tripled qhov cuam tshuam lub zog thiab tensile elongation ntawm incompatible HDPE / PP 70/30 muab thaum tuav lub siab dua modulus imparted los ntawm PP tivthaiv, "nws hais ntxiv, rau qhov tsis tshua muaj kub plasticity yuav tsum tau, Koom POE muab kev cuam tshuam lub zog ntawm ambient kub. vim qhov hloov pauv iav tsis tshua muaj kub.
Hais txog tus nqi ntawm cov elastomers tshwj xeeb no, ExxonMobil's Cortez tau hais tias: "Nyob rau hauv cov khoom siv rov ua dua tshiab, nws tseem ceeb heev kom sib npaug ntawm tus nqi thiab kev ua haujlwm.Nrog Vistamaxx polymers, kev ua haujlwm ntawm cov khoom siv rov ua dua tuaj yeem txhim kho, tso cai rau cov resins siv rau hauv cov ntawv thov uas cov khoom siv rov ua dua tuaj yeem tau txais txiaj ntsig ntau dua.Thaum ua tau raws li qhov kev thov rau cov khoom siv ua haujlwm siab. Yog li ntawd, cov neeg siv khoom siv rov ua dua tshiab tuaj yeem muaj sijhawm ntau dua los ua lag luam lawv cov khoom siv rov ua dua tshiab, tsis yog tus nqi tsuas yog tus neeg tsav tsheb loj, cia lawv tsom mus rau cov kev cai sib xyaw thiab cov khoom siv. "
"Ntxiv rau qhov muaj peev xwm rov ua dua cov khoom sib xyaw polyolefins, peb kuj tseem ua haujlwm los txhawb kev rov ua dua tshiab ntawm cov khoom sib txawv xws li polyolefins nrog engineering plastics xws li nylon thiab polyester.Peb tau muab ntau cov khoom siv polymers, tab sis cov kev daws teeb meem tshiab tseem nyob hauv kev txhim kho.tab tom tsim los tsim kom muaj ntau yam kev sib xyaw ntawm cov yas uas muaj nyob rau hauv ntim, infrastructure, tsheb thauj mus los thiab cov neeg siv khoom siv. "
Styrene thaiv copolymer thiab tshuaj hloov kho polyolefins yog lwm hom ntaub ntawv uas tau txais kev saib xyuas raws li compatibilizers rau kev txhawb zog thiab txhim kho cov compatibility ntawm recycled resins.
Kraton Polymers muaj CirKular + styrenic thaiv copolymer platform uas muaj kev ua tau zoo ntxiv cov khoom ntxiv rau cov khoom siv rov ua dua tshiab thiab rov ua dua tshiab.Julia Strin, tus thawj coj ntawm kev lag luam thoob ntiaj teb rau Kraton Specialty Polymers, taw qhia rau ob qib ntawm tsib qib: CirKular + Compatibility Series (C1000, C1010, C1010) thiab CirKular + Performance Enhancement Series (C2000 thiab C3000).Cov additives no yog ntau yam thaiv copolymer raws li styrene thiab ethylene / butylene (SEBS).Lawv muaj cov khoom siv tshwj xeeb, suav nrog kev ua haujlwm siab ntawm chav tsev lossis qhov kub thiab txias, ua kom yooj yim rau cov tawv nqaij thiab cov khoom cuam tshuam, txhim kho kev tiv thaiv kev ntxhov siab tawg, thiab txhim kho cov txheej txheem.Circular + cov khoom kuj muab ntau cov khoom sib xyaw ua ke rau cov yas yas, PCR thiab PIR pov tseg.Nyob ntawm qib, lawv tuaj yeem siv rau hauv PP, HDPE, LDPE, LLDPE, LDPE, PS thiab HIPS, nrog rau cov polar resins xws li EVOH, PVA thiab EVA.
"Peb tau pom tias nws muaj peev xwm rov ua dua cov khoom pov tseg polyolefin sib xyaw thiab rov ua dua rau hauv cov khoom muaj txiaj ntsig dua."
"CirKular+ cov khoom siv rov ua dua tshiab tso cai rau PCR rov qab siv dua los ntawm kev txhim kho cov khoom siv kho tshuab thiab txhawb kev tsim cov khoom siv polyolefin-based monomaterial, yog li ua kom cov ntsiab lus PCR ntau tshaj 90 feem pua," hais Stryn.unmodified resin.Kev ntsuam xyuas tau pom tias cov khoom siv CirKular + tuaj yeem kho cua sov txog tsib zaug rau kev siv ntau zaus. "
Lub CirKular + ntau yam ntawm cov expanders yog ntau cov resin expanders rau kev kho dua tshiab PCR thiab PIR rov qab kwj, feem ntau ntxiv ntawm 3% mus rau 5%.Ob qho piv txwv ntawm kev siv cov khib nyiab sib xyaw ua ke suav nrog kev txhaj tshuaj molded cov qauv ntawm 76% -PCR HDPE + 19% -PCR PET + 5% Kraton + C1010 thiab cov qauv ntawm 72% -PCR PP + 18% -PCR PET + 10% Kraton + C1000..Nyob rau hauv cov piv txwv no, notched Izod cuam tshuam lub zog tau nce los ntawm 70% thiab 50%, feem, thiab lub zog tawm los ntawm 40% thiab 30%, thaum tuav nruj thiab txhim kho cov txheej txheem.PCR LDPE-PET blends kuj tau pom qhov ua tau zoo sib xws.Cov khoom no kuj siv tau rau nylon thiab ABS.
Lub CirKular + Performance Enhancement Series yog tsim los txhim kho cyclic sib xyaw PCR thiab PIR kwj ntawm polyolefins thiab polystyrene ntawm qib sib ntxiv ntawm 3% mus rau 10%.Tsis ntev los no kev txhaj tshuaj molding ua tiav: 91% -PCR PP + 9% Kraton + C2000.Cov qauv tsim muaj 110% kev txhim kho hauv kev cuam tshuam kev sib npaug ntawm cov khoom sib tw."Cov ntawv thov rPP siab kawg hauv kev siv tsheb thiab kev lag luam xav tau kev txhim kho zoo li no.Qhov no kuj tseem tuaj yeem siv rau kev ntim khoom, tab sis nrog cov kev cai nruj me ntsis, tus nqi ntawm C2000 yuav raug txo, "Streen tau hais.
Kraton + tuaj yeem ua ntej sib xyaw lossis qhuav-kib nrog cov yas siv ua ntej molding, extrusion lossis ua ib feem ntawm cov txheej txheem rov ua dua tshiab, Stryn hais.Txij li thaum pib CirKular + ob peb xyoos dhau los, lub tuam txhab tau ua tiav kev saws me nyuam ntxov hauv thaj chaw xws li kev lag luam pallets, ntim khoom noj thiab dej haus, cov khoom siv tsheb thiab cov menyuam yaus lub rooj zaum.CirKular + tseem tuaj yeem siv rau ntau yam kev siv xws li kev txhaj tshuaj lossis compression molding, extrusion, rotational molding thiab compounding.
Polybond 3150/3002 yog ib feem ntawm SI Group qhov kev nthuav dav ntawm Polybond chemically modified polyolefins thiab tuaj yeem siv los ua ib qho kev sib khi thiab sib xyaw ua ke.Nws yog ib tug txiv neej anhydride grafted polypropylene uas ua rau recycled polypropylene tau tshaj txhua hom nylon.Raws li John Yun, tus thawj saib xyuas kev lag luam thiab kev txhawb nqa kev lag luam, ntawm qhov kev siv tau zoo ntawm 5%, nws nthuav tawm ntau dua triple Izod notched cuam tshuam lub zog thiab thim rov qab Izod cuam tshuam lub zog.Irfaan Foster, tus thawj coj ntawm kev tsim kho kev lag luam, sau tseg tias thawj daim ntawv thov yog lub tsheb soundproofing.Tsis ntev los no, nws tau raug siv nyob rau hauv recycled polypropylene thiab nylon blends rau underfloor panels, underhood Cheebtsam, thiab qab dashboards.
Lwm qib yog Polybond 3029, ib tug txiv neej anhydride grafted high-density polyethylene qhia ob xyoos dhau los ua ib qho ntxiv los txhim kho kev sib raug zoo ntawm cov ntoo-yas composites.Raws li Yun, nws zoo li lub tuam txhab tab tom taug qab kom sib haum nrog 50/50 PCR / ntshiab HDPE sib xyaw.
Lwm chav kawm ntawm compatibilizers yog raws li titanium-aluminium chemistry, xws li titanate (Ti) thiab zirconate (Zr) catalysts muab los ntawm Kenrich Petrochemicals thiab muag rau compounders thiab moulders.Lub tuam txhab cov khoom muaj xws li ib tug tshiab catalyst nyob rau hauv masterbatch los yog hmoov daim ntawv uas ua raws li ib tug compatibility additive rau ntau yam polymers, xws li polyolefins, bioplastics xws li PET, PVC thiab PLA.Nws siv hauv PCR sib xyaw xws li PP / PET / PE tau txais lub zog, raws li Kenrich tus thawj tswj hwm thiab tus tswv koom nrog Sal Monte.Qhov no tau tshaj tawm los ua kom cov khoom tsim tau extrusion thiab txo cov sij hawm txhaj tshuaj molding.
Ken-React CAPS KPR 12 / LV hlaws thiab Ken-React KPR 12 / HV hmoov tau tshaj tawm los kho PCR rau nws lub xeev qub.Monte tau hais tias cov khoom lag luam yog qhov tshwm sim ntawm kev sib txuas ntawm lub tuam txhab tshiab LICA 12 alkoxy titanate catalyst nrog cov hlau sib xyaw ua ke uas yog "tus nqi ntau dua.""Peb muab CAPS KPR 12 / LV granules nyob rau hauv ntau npaum li cas ntawm 1.5% mus rau 1.75% ntawm tag nrho qhov hnyav ntawm tag nrho cov khoom siv rov qab ntxiv rau hauv lub thawv, ib yam li masterbatch, thiab txo cov txheej txheem kub los ntawm 10-20%, kom tswj cov shear. ntawm cov tshuaj tiv thaiv sib tov.Lawv ua haujlwm ntawm qib nanometer, yog li yuav tsum muaj qhov sib xyaw ua ke ntawm cov khoom sib xyaw, thiab cov yaj yuav tsum muaj lub zog siab. "
Monte hais tias cov additives no yog cov zoo compatibilizers rau additive polymers xws li LLDPE thiab PP thiab polycondensates xws li PET, organic thiab inorganic fillers, thiab bioplastics xws li PLA.Cov txiaj ntsig zoo suav nrog 9% txo qis hauv extrusion, txhaj tshuaj molding thiab tshuab moulding kub thiab 20% nce hauv kev ua haujlwm ceev rau feem ntau cov thermoplastics unfilled.Cov txiaj ntsig zoo sib xws tau txais nrog kev rov ua dua 80/20% LDPE / PP sib xyaw.Nyob rau hauv ib rooj plaub, 1.5% CAPS KPR 12 / LV tau siv los xyuas kom meej qhov sib xws ntawm peb PIR resins: kawm tiav fused zaj duab xis LLDPE, 20-35 MFI sib xyaw txhaj tshuaj molded polypropylene copolymer hau, thiab thermoformed PET zaub mov foldout ntim.Sib tov PP / PET / PE sib tov rau 1/4 "loj.mus txog ½ nti.Flakes thiab melts yog sib xyaw rau hauv kev txhaj tshuaj molding pellets.
Interface Polymers 'patented diblock additive thev naus laus zis tshaj tawm tias kov yeej qhov tsis sib xws ntawm polyolefins ntawm qib molecular, tso cai rau lawv ua tiav.(Duab: interfacial polymers)
Kev faib khoom lag luam SACO AEI Polymers yog tus tsim tshwj xeeb ntawm Fine-Blend hauv Suav teb, uas tsim ntau yam sib xyaw ua ke rau polypropylene, nylon, PET, engineering thermoplastics thiab biopolymers xws li PLA thiab PBAT, suav nrog cov khoom siv rov ua dua tshiab, cov khoom siv ntxiv thiab cov saw txuas ntxiv.Mike McCormach tus thawj coj ua lag luam tau hais.Cov khoom pab cuam muaj xws li cov khoom siv tsis sib haum xeeb, feem ntau yog thaiv thiab graft copolymers lossis random copolymers uas tsis koom nrog cov tshuaj tiv thaiv tshuaj thaum sib xyaw polymers.BP-1310 yog ib qho piv txwv qhov sib ntxiv ntawm 3% mus rau 5% txhim kho kev sib raug zoo ntawm cov khoom siv rov ua dua tshiab ntawm polypropylene thiab polystyrene.Ib qho ntxiv los txhim kho kev sib raug zoo ntawm cov khoom siv rov ua dua PE / PS yog nyob rau hauv kev txhim kho.
Fine-Blend reactive compatibilizers txhim kho kev sib raug zoo los ntawm kev siv tshuaj lom neeg nrog nkauj xwb polymer thaum sib xyaw, suav nrog ECO-112O rau siv PET, polycarbonate thiab nylon;HPC-2 rau ABS thiab siv PET compatibilizer;thiab SPG-02 rau zus tau tej cov polypropylene thiab recycled polypropylene.PET tau tshaj.Lawv muaj cov pab pawg epoxy uas tuaj yeem hnov mob nrog cov khoom siv polyester cov hydroxyl pawg los txhim kho cov tawv nqaij thiab kev sib raug zoo, McCormach tau hais.Kuj tseem muaj CMG9801, tus txiv neej anhydride grafted polypropylene uas tuaj yeem hnov mob nrog cov amino pawg ntawm nylon.
Txij li thaum xyoo 2016, lub tuam txhab British Interface Polymers Ltd. tau tsim nws tus kheej Polarfin diblock copolymer additive technology, uas tau tshaj tawm tias kov yeej cov khoom siv molecular incompatibility ntawm polyolefins, tso cai rau lawv rov qab siv dua.Cov diblock additives no yog tsim rau cov nkauj xwb thiab rov siv dua polyethylene thiab polypropylene compounds, nplooj ntawv thiab zaj duab xis.
Lub tuam txhab ua yeeb yaj kiab loj tau ua haujlwm ntawm qhov project los ua cov yeeb yaj kiab multilayer yam tsis muaj kev poob loj ntawm kev tsim khoom.Tus Thawj Coj Kev Txhim Kho Kev Lag Luam Simon Waddington tau hais tias txawm tias nyob rau theem qis, Polarfin tau tshem tawm gelling, ib qho teeb meem uas cuam tshuam rau kev rov ua dua ntawm polyolefin films siv cov khoom siv rov ua dua tshiab."Peb tau ua tiav pom tau tias polyolefin sib xyaw cov khoom pov tseg tuaj yeem rov ua dua thiab rov ua dua tshiab rau hauv cov khoom muaj txiaj ntsig siv peb cov khoom siv Polarfin additive."
Raws li ExxonMobil's Cortes, kev sib raug zoo (xws li Vistamaxx nrog cov khoom siv rov ua dua PE / PP) tuaj yeem pom tau los ntawm kev txhim kho cov khoom siv xws li kev cuam tshuam.(Duab: ExxonMobil)
Nyob rau hauv ntxaib ntsia hlau compounding, feem ntau engineers paub qhov kom zoo dua ntawm muaj peev xwm configure ntsia hlau ntsiab.Nov yog yam koj yuav tsum paub txog kev txheeb cov thoob thoob.
Tshawb nrhiav cov qauv spatial thiab/lossis lub cev mus rau lub cev los muab cov lus qhia thaum tshawb xyuas qhov txuas tsis zoo lossis txiav txim siab lub hauv paus ua rau muaj teeb meem ua haujlwm.Lub tswv yim rau kev txheeb xyuas thiab kho qhov laj thawj uas txheeb xyuas tau yog thawj zaug txiav txim siab seb qhov teeb meem puas yog mob ntev lossis ib ntus.
Insight Polymers & Complexers siv nws cov kev txawj ntse hauv polymer chemistry los tsim cov ntaub ntawv tiam tom ntej.
Post lub sij hawm: Lub Xya hli ntuj-28-2023