Pab tso zog rau kev nyob ntev nrog PVA 1788

PVA 1788 Yog Li Cas Thiab Yuav Li Cas Nws Lub Molecular Properties Coob Tshaj Plaws Rau Kev Txaus Siab

Lub Npe Kim Ho, Tus naj npawb ntawm Hydrolysis, Thiab Qhov Tseem Ceel ntawm Molecular Weight

Yog tias PVA 1788 muaj peev xwm zoo li cas? Nyob rau hauv qhov peb tsim tib ntim no, peb sau nrog cov molekhlis. Nyob rau hauv qhov chaw 87 txog 89% hydrolysis, qhov khoom no tau txais sijhawm tseem ceeb. Muaj txaus hydroxyl groups los tsim cov cuab yeej meej ntau ntawm cov molekhlis thiab nyob ib puag ncig ntawm qhov chaw nres. Tab sis ntawm no yog tias muaj ntau acetate groups tshwm sim, qhov no yuav cuam tshuym nrog qhov chaw crystalline thiab cuam tshuym nrog qhov kub. Ntawm qhov chaw molecular weight, PVA 1788 muaj li 130,000 grams per mole, uas pab tau cov kab nteev nteev ntau dua thiab tso tawm tau ntau. Cov kev sib txhuam no pab tau rau cov khoom loj dua, txawm li 40% zoo dua lwm yam PVA uas muaj molecular weight tsuas me ntsaws. Vim li cas thaum chaw nyuaj siab? Ib tug polymer feem ntau yuav soft thiab tsis muaj form, tab sis PVA 1788 tsis li ntawd. Qhov structure tseem ceeb no nyob ib siab kom zoo rau qhov chaw nyuaj siab, khiav kom tag nrho yooj yim thaum chaw nyuaj siab hlo sij hnav lossis nyob rau qhov chaw sib txawv.

PVA 1788 Lub Tswj Xaiv Rau Lub Npav Thiab Kev Sib Puag Nyob Zoo Li Cas Thiaj Li Pom Ntau Ntau Kev Nyiaj Loj

PVA 1788 tsim lub npav muaj zog uas tso siab nyiaj rau ib puag ncig ntawm chav nyob. Qhov xav tias yuav ua rau cov khoom no txawv yog tag nrho cov hydroxyl group nyob rau saum pem teb uas sib thooj nrog cov khoom polar zoo li cellulose, dej, thiab ntaub qhuav los ntawm kev sib thooj hydrogen zoo. Qhov no tseem pab ntxiv kev tiv thaiv kom tsis pub luv dua li glues tshaib hauv 25 mus rau 35 feem pua. Ib qho yam zoo dua yog lub npav no sib kis nyob rau hauv molecular level, uas tiv thaiv kom tsis pub muaj khaum leeg tom qab rov qab plaws ntau xyoo ntau hnub. Yog tias polymer tau sib thooj ntxiv lawm ces yuav tseem zoo dua, tso cov chaw nyob khaug dua kom dej tsis tau nkag mus soj ntsuam. Cov kev sim pom tias qhov no tua dej nkag mus hauv ntau li 60 feem pua, ua rau PVA 1788 nyob ntev dua hauv qhov chaw nyob nyob meem zoo li nyiaj khoom lag luam, khoom siv rau tsev, thiab npav dej uas yuav tsum tau zoo meej.

PVA 1788 raw rau kev txhim kho tias nyob dai: Qhov kev pab, nuj nqi txog kev nyob dai, thiab kev soj ntsuam

Kev txhim kho kev nyob dai los ntawm kev sib thoo, kev sib tso, thiab kev faib tshuaj

Yog li cas PVA 1788 muaj zog tshuab ntxuav zoo heev? Muaj peb yam cuab meej uas pib txawj sib poob rau kev pab cuam. Thaum ob, muaj kev sib txhab nyob rau sab nraud uas sib txuas nrog lwm hom khoom. Thaum ob, cov hmoob polymer tso caij nyob rau thaum sau, uas tseem pab tso caij ntau thaum cov kab ntsug pib tshwm sim. Thaum thib ob, kev txiav txim siab tso caij sib npab txoj kab ntawm qhov sib txuas kom tsis txhob tso caij rau ib qhov chaw uas nws yuav tuaj yeem los. Cov phiaj xwm no txhob tshwm sim thaum khoom muaj hydrolysis li 87 mus 89 percent thiab nyob rau hauv qhov chaw sib txuas molecular weight li 85,000 mus 124,000 grams per mole. Qhov chaw no pab tso caij rau tus tshuab kom nyuaj siab tab sis tsis txhob tig rau ib leeg. Cov kws tshuaj ntawm American Coatings Association hais tias yog vim qhov sib txuas ntawm cov yam ntxwv no tib neeg sawv daws tso PVA 1788 ua tus thawj khoom tshuaj tiv thaiv rau kev tsim tshuab ntxuav siv rau kev tsim kho hlwb thiab kev tsim kho raj.

Kev Tshawb Nrhiav Nyob Zej Zog: Qhov Tseem Ceeb ntawm Kev Ntxuav Tom & Kev Tshawb Nrhiav ntawm PVA 1788-Modified Adhesives

Kev tshawb nrhiav nyob zej zog—tsim los sim 5–10 xyoo ntawm kev siv hauv cheeb tsam—thov kom paub tias PVA 1788-modified adhesives kuj muaj qhov tseem ceeb dua li 80% ntawm qhov tseem ceeb dhau los tom qab muaj kev ntxuav tom, UV irradiation, thiab kev txom yeem ntawm dej ntsuag. Txij li ASTM D1002 (lap shear) thiab ASTM D903 (peel) standards:

• Qhov tseem ceeb ntawm kev ntxuav tom loj dua 30–40% hauv hlau, neeg tsim, thiab polymer substrates
• Qhov tseem ceeb ntawm kev tshawb nrhiav zoo dua 25–35% hauv txhua yam khoom tshawb nrhiav

Qhov tseem ceeb no txwv PVA 1788 ua ib qhov tseem ceeb rau kev xaum ntev—tshwj tsis yog thaum kev tseem ceeb hauv kev txom yeem tsis tuaj yeem txiav.

Txhim Kho Kev Tsim Kev Sib Chig Los Nrhiav Qhov Tseem Ceeb ntawm PVA 1788

Aldehyde- thiab Borate-Mediated Cross-Linking Rau Kev Tseem Ceeb ntawm Dej Thiab Kev Tseem Ceeb ntawm Txheat

Thaum sib txhuam keem hauv chawj tse, nws hlo li PVA 1788 los ntawm nws tus tsim nyob rau hauv daim duab linear uas muaj kev nyob siab nrog dej mus rau ib yam dab neeg nyob qhov chaw tse tshaj plaws. Qhov ntxuav glutaraldehyde tshwm sim cov kab uas muaj zog acetal nyob saum cov kauv hydroxyl nyob ze. Tus no nyuaj siab dej sov dua los ntawm qhov chaw 40 mus rau 60 feem pua. Tom qab ntawd, nws tso tseg thaum muaj yam khoom kuaj ntsuas dua saum 200 degrees Celsius. Tom qab ntawd, muaj cov ion borate uas tsim cov chaw sib tw zoo tshaj plaws nrog ob lub kauv alkohol raw. Lawv txhim kho tus kheej thaum muaj kev txiav txim, yog li yam khoom tuaj yeem tiv thaiv kev ruaj siab zoo dua tab sis tsis txhob tshav. Txoj kev no txhua yam tshwm sim rau peb tau ib tug ntawm peel strength nyob saum 85% tom qab kuaj ntsuas ib tug ntawm humidity. Yog li no tseem ceeb heev rau kev tsim cov adhesive nyob ntev rau kev siv rau kev sib cuag khoom nyob saum dej, thiab ntau yam khoom siv rau tsev uas feem ntau yuav tshuav.

Kev Kuab Tsim Siab UV- thiab Enzyme-Cuam Tshwm Nyob rau Hauv PVA 1788 Kawm ntawv Txhua Yooj Yim

Kev txhim kho tib meej tshiab tau tshwm sim los ntawm kev pab cuam tshuaj ntau yam uas tsis tuaj yeem ua rau muaj kev phom sij, thiab tsis txhob hlilees lus qhia. Nrog kev siv tshav UV, acrylates hla rau hauv PVA 1788 polymer chains, uas txhais tau tias khoom siv tuaj yeem harden tas li nyob rau saum ob xyoos ntawm ib feeb, thiab tseem zoo ib si thaum sau ua ntej ntaus rau hauv dej rau kev them. Kuj muaj kev pab cuam nrog kev siv enzymes, piv txwv li transglutaminase lossis laccase, uas tsim cov kab ntsug uas tuaj yeem decompose nyob rau hauv daim kab ntsug, thaj chaw compost. Cov kab no muaj zog tshaj tawv zoo ib yam li formaldehyde kev kho vajtse, tab sis break down tas li rau hauv peb lub lim hli, thaum composted nyob rau hauv tsev compost. Yog vim li cas cov kev pab cuam no zoo heev? Lawv txo tus leeg VOC emissions nyob rau sab saud ob thirds dhau dua kev txhim kho tib meej dhau los. Tom qab ntawv, lawv raug rau cov standard tseem ceeb tswj los ntawm EPA thiab European Union rau adhesives tshiab, txhim kho kev pab cuam rau cov neeg tsim khoom uas xav mus rau green, tsis txhob hlilees lus qhia khoom.

Kev Pab Txhim Keb: Lub Adhesives Thim Sauv Siv PVA 1788's Qhov Tshwm Sim Thiab Qhov Yuav Puav

Yog li cas PVA 1788 muaj txiaj ntsig yog vim nws sib cuag zoo nrog kev sib xyuas zoo nrog kev tso nraim rau lub taub hau ntawm nws qhov chaw tsim. Glues thaj yas petrochemical feem ntau nyob ib txhis, tab sis no tseem break down tas rau hauv din lossis wastewater treatment plants tom qab ib co xyoos thaum pom oxygen nyob rau hauv qhov chaw muaj. Peb tau rov sim no raws li cov standard ISO 14851 thiab OECD 301B, yog li muaj txiaj ntsig meej meej rau cov lus nug no. Qhov no txhais tau tias muaj meno waste xa mus rau landfills thiab muaj menos plastic particles tshwm los rau hauv peb lub hnub no. Qhov keeb kwm uas tso nraim rau hauv qhov chaw tsim yog nws muaj qhov zog txaus rau kev siv hauv tsev tsim khoom, tab sis tseem nyiam rau hauv qhov chaw nyob. Tsev tsim khoom hauv Europe thiab California nyiam no heev vim lawv yeej tsum ua raws koob yau ntawm kev siv khoom siv ib zaug thiab lwm yam kev saib xyuas rau lub hnub no. Thaum ntau tus kheev nkhaus dua npaj siv kev tswj hauv qab chaws, PVA 1788 tsis yog ib txoj hlua siv ntxiv. Nws txhais tau tias ib qhov loj dua - ib qhov tseem ceeb rau kev tsim kho kev sib xyuas yooj yim hauv qab teb.

FAQ

Lub Tswv Rog Yog PVA 1788?

PVA 1788 yog hom polyvinyl alcohol uas muaj qhov sib txawv hauv tus cwj pwm uas tiv thaiv kev puag, ua rau nws yog qhov leej hnub rau ntau yam kev siv hauv tshuab ntau.

PVA 1788 ua li cas tiv thaiv kev puag?

PVA 1788 tiv thaig kev puag los ntawm qhov loj ntawm hydrolysis, qhov loj ntawm cwj pwm, qhov tswj hwm los tsim daim ntawv, thiab qhov tso caij ntawm interfacial adhesion, uas chia lub zog tshem tshem kom meej meej thiab tiv thaiv kev puag uas muaj nyob rau hauv dej.

Cov kev siv twg tau nyob rau PVA 1788 tiv thaiv kev puag?

Cov kev siv xws li kho mob, khoom siv rau tsev, thiab daim ntawv hlwb hlwb muaj pa neej ntev tau nyob rau PVA 1788 tiv thaiv kev puag, txhawj xeeb tias nyob rau qhov chaw nyuaj.

Puas muaj cov cuab yeej tshiab uas zoo tias ntxiv rau PVA 1788?

Yea, PVA 1788 tau siv hauv kev tsim adhesive tshaj lij nyob rau hauv daim ntawv phem uas tuaj yeem sib puag ncig nyob rau hauv vaj tse, los yog nyob rau hauv dej nruj, kom txo qhov tsis zoo rau hauv vaj tse.