Magawo otsatirawa akufotokoza za kusintha kwa viscoelastic kwa thovu la polyurethane gawo ndi gawo, kuphatikiza njira zochitira zinthu, zochitika zowoneka, ndi zinthu zothandiza pakupanga.

1. Mfundo Zoyambira

1. Kukhuthala

Kukhuthala kumayimira kukana kwa chinthu kuyenda ndipo kumawonetsa khalidwe lake lokhuthala. Kukhuthala kwakukulu kumatanthauza kusayenda bwino.

2. Kutanuka

Kutanuka kumatanthauza kuthekera kwa chinthu kubwezeretsa mawonekedwe ake oyambirira pambuyo pa kusinthika. Kutanuka kwakukulu kumapereka kukana bwino ku kusinthika ndi kugwa kwa thovu.

3. Gel Point

Mfundo ya gel ndi kusintha kofunikira komwe dongosolo limasintha kuchoka pamadzi oyenda kupita ku netiweki yolimba yosayenda. Ndi malo ofunikira kwambiri ogawanitsa thovu.

4. Zochitika Zonse

Pa nthawi yonse ya thovu, kukhuthala kumawonjezeka nthawi zonse, pomwe kukhuthala kumakula pang'onopang'ono kuchoka pa kufooka kwambiri mpaka kufika pa kulamulira. Pambuyo pa gelation, kukhuthala kumakhala khalidwe lolamulira dongosolo.

2. Kusintha kwa Viscoelastic pogwiritsa ntchito gawo la thovu

Gawo 1: Gawo Loyamba Losakaniza (Nthawi Yoyambitsa Kusakaniza Musanayambe Nthawi Yopaka Kirimu)

Boma

Polyol, isocyanate, ndi zowonjezera zangosakanikirana kumene. Machitidwe a mankhwala amapitirira pang'onopang'ono, kupanga mpweya kumakhala kochepa, ndipo dongosololi limakhalabe lamadzimadzi ofanana.

Makhalidwe a Viscoelastic

• Kukhuthala kochepa komanso kuyenda bwino kwambiri.
• Pafupifupi palibe kusinthasintha.
• Pogwiritsa ntchito mphamvu zakunja, zinthuzo zimayenda momasuka ndipo kusintha kwake sikungasinthe.

Chifukwa cha Kusintha

Maunyolo a mamolekyulu sanapange maulalo ofunika kwambiri. Chiŵerengero cha zochita za NCO–OH chikutsikabe, ndipo palibe netiweki ya polima yomwe yakhazikitsidwa.

Kuyang'anira Kupanga

Chosakanizacho chimawoneka chowonekera bwino kapena ngati mkaka pang'ono ndipo chimayenda momasuka.

Gawo 2: Gawo la Kirimu (Kuyambitsa Thovu)

Boma

Kuchuluka kwa zochita kumawonjezeka. Madzi amakumana ndi isocyanate kuti apange kuchuluka kwakukulu kwa CO₂. Dongosolo limasanduka loyera, thovu laling'ono limaonekera, ndipo kukula koyamba kumayamba.

Makhalidwe a Viscoelastic

• Kukhuthala kumawonjezeka mofulumira pamene oligomers ndi ma molecular chains ataliatali amapangidwa.
• Kufooka kwa kusinthasintha kumayamba kuonekera chifukwa cha kupangika kwa mgwirizano wa unyolo woyamba.
• Dongosololi limakhalabe lolimba kwambiri ndipo limapitirira kuyenda ndi kutambasuka.

Mbali Yaikulu

Ma thovu amapangidwa ndikukula mosalekeza. Dongosololi limadalira makamaka kukhuthala kwake kuti lisunge thovu la mpweya ndikuletsa kutuluka kwa mpweya.

Gawo 3: Gawo Lokwera (Nthawi Yotulutsa Thovu Lambiri Musanayambe Kutulutsa Thupi)

Boma

Kuchuluka kwa mpweya kumafika pachimake. Mpweya wambiri umapangidwa, kuchuluka kwa thovu kumakula mofulumira, ndipo maselo amakula mwachangu. Iyi ndi nthawi yofunika kwambiri popanga thovu.

Makhalidwe a Viscoelastic

• Kukhuthala kwa thupi kukupitirirabe kukwera kwambiri.
• Kuyenda kwa madzi kumachepa kwambiri.
• Machitidwe olumikizana amakula, zomwe zimapangitsa kuti kusinthasintha kuchuluke mofulumira.
• Khalidwe la viscoelastic limayamba kuonekera kwambiri, pang'onopang'ono likusinthira ku ulamuliro wotambasuka.
• Zinthuzo zimakhala ndi mphamvu yokoka komanso kukana kugwa.

Thovu likatambasulidwa, limasinthasintha koma limabwereranso pang'ono mphamvuyo ikachotsedwa. Thovu lomwe likukula limakhazikika bwino mkati mwa matrix.

Zotsatira za Njira

• Ngati kusinthasintha sikukwanira ndipo kukhuthala kukukulirakulira, thovu limatha kusweka, kusonkhana, kapena kugwa.
• Ngati kusinthasintha kwa thovu kumayamba msanga kwambiri kapena mwamphamvu kwambiri, kukula kwa thovu kumakhala kochepa, zomwe zimapangitsa kuti kukhuthala kwa thovu kukhale kwakukulu.

Gawo 4: Gel Point (Gawo Losinthira Lofunika Kwambiri)

Boma

Netiweki yolumikizana ya magawo atatu imakhazikitsidwa. Kutulutsa thovu ndi gelation zimafika pamlingo woyenera, zomwe zimapangitsa kuti izi zikhale mfundo yofunika kwambiri mu ndondomeko yonseyi.

Kusintha kwa Viscoelastic

• Dongosolo limataya mphamvu yake yoyendera.
• Kukhuthala kooneka ngati kumayandikira kosatha.
• Kutanuka kumakhala chinthu chachikulu.
• Kusintha kwa thupi kumakhala kolimba kwambiri, ndipo kumachira msanga pambuyo popanikizika kapena kutambasula.
• Kapangidwe ka maselo kamakhazikika nthawi zonse pamene makoma a maselo amalimba.

Kufunika kwa Kupanga

• Kuchuluka kwa madzi m'thupi (gelation) kungayambitse kufalikira kosakwanira komanso kuchuluka kwa thovu.
• Kuchuluka kwa mpweya m'thupi kungayambitse kutayika kwa mpweya, kuchepa kwa thovu, komanso kugwa.

Gawo 5: Kuchira ndi Kukhwima (Pambuyo pa Kubereka)

Boma

Magulu otsala omwe akhudzidwa akupitiriza kuchitapo kanthu, zomwe zimalimbitsa kwambiri netiweki yolumikizidwa. Kufutukuka kwa thovu kumasiya, ndipo pang'onopang'ono zinthuzo zimalimba.

Makhalidwe a Viscoelastic

• Kuchulukana kwa Crosslink kukupitirirabe kukwera.
• Kulimba kumawonjezeka pang'onopang'ono.
• Kutanuka kumakhazikika.

Pa thovu losinthasintha:

• Kusinthasintha kwakukulu kumasungidwa.
• Kulimba mtima ndi kulimba bwino kumasungidwa.

Pa thovu lolimba:

• Kutanuka kumachepa.
• Zinthuzo zimasintha kukhala zolimba.
• Kusintha kwa kapangidwe kake kumakhala pulasitiki kwambiri kuposa kutanuka.

Zotsalira zamkati zimakhalapo poyamba koma pang'onopang'ono zimatulutsidwa panthawi yowuma, zomwe zimathandiza kuti zinthu za viscoelastic zikhale zokhazikika.

Kusintha Kotsatira

Pambuyo pokonza bwino pamalo ozungulira, kulumikizana kumakhala kokwanira, ndipo mawonekedwe a makina ndi a viscoelastic amakhalabe olimba.

3. Zinthu Zofunika Kwambiri Zomwe Zimakhudza Khalidwe la Viscoelastic

1. Zothandizira (Chofunika Kwambiri Chowongolera)

Zothandizira Kuwombera

• Kufulumizitsa kupanga gasi.
• Limbikitsani kukula kwa viscosity koyambirira.
• Pangani kukula kwa thovu kuti lipitirire mofulumira.

Zothandizira za Gel

• Limbikitsani zochita zolumikizana.
• Konzani netiweki yotanuka msanga.
• Fupikitsani nthawi ya gel.

Kusalinganika kwa Catalyst

Kusalinganika bwino pakati pa kuphulika ndi ma catalyst a gel kumasokoneza kufanana kwa thovu ndi gelation, kusokoneza mawonekedwe a viscoelastic, ndipo kungayambitse kugwa kwa thovu, kuchepa, kapena kapangidwe ka maselo okhuthala.

2. Kutentha kwa Zinthu Zopangira

Kutentha Kwambiri

• Imathandizira kuchuluka kwa zochita zonse.
• Zimawonjezera kuchuluka kwa kukhuthala ndi kusinthasintha kwa khungu.
• Zimayambitsa gel yosalala kale.

Kutentha Kotsika

• Amachepetsa kuchuluka kwa zochita.
• Zimapangitsa kuti pang'onopang'ono zinthu za viscoelastic ziwonjezeke.
• Zimachedwetsa kusungunuka kwa mpweya ndipo zimawonjezera chiopsezo cha kutayika kwa mpweya.

3. NCO Index (Isocyanate Index)

Chiwerengero Chapamwamba cha NCO

• Zimalimbikitsa kulumikizana kwamphamvu.
• Kumawonjezera kusinthasintha ndi kulimba mwachangu.
• Amapanga thovu losalimba kwambiri.

Chiyerekezo Chotsika cha NCO

• Zotsatira zake n'zakuti palibe kulumikizana kokwanira.
• Zimapangitsa kuti kukhuthala kukhale kofooka komanso kukhuthala kochulukirapo.
• Amapanga thovu lofewa lomwe limasinthasintha kwambiri komanso silichira bwino.

4. Zothira madzi ndi zodzaza

Zopangira Silikoni

• Sinthani kulamulira kwa kupsinjika kwa nkhope.
• Limbikitsani kufalikira kwa viscoelastic kofanana mu thovu lonse.
• Pewani kapangidwe ka maselo kosagwirizana komwe kumachitika chifukwa cha kukhuthala kwa malo kapena kusiyana kwa kusinthasintha.

Zodzaza Zosapangidwa ndi Zachilengedwe

• Wonjezerani kukhuthala kwa dongosolo loyambira.
• Kuchepetsa kusinthasintha.
• Pangani kapangidwe ka thovu kukhala kolimba kwambiri.

5. Kapangidwe ka Polyol

Ma Polyol Ogwira Ntchito Kwambiri

• Pangani maukonde olumikizana molimba mosavuta.
• Wonjezerani kusinthasintha ndi kulimba mwachangu.

Ma Polyol Olemera Kwambiri, Unyolo Wautali

• Pangani njira yolumikizirana pang'onopang'ono.
• Pangani khalidwe lofewa lotanuka.
• Sungani kukhuthala kwa nthawi yayitali.
• Ndi khalidwe la mapangidwe osinthasintha a thovu.

4. Chidule: Kachitidwe Konse ka Viscoelastic Panthawi Yotulutsa Thovu

Mwachidule, njira yonse yotulutsa thovu ndi kusintha kwa rheological komwe dongosolo limasintha kuchokera kumadzi okhuthala okhamunetiweki ya elastomeric yolumikizidwa ndi magawo atatu.

Kugwirizana pakati pakukulitsa ndi kukulitsa thovu, monga momwe zimasonyezedwera ndi kusintha kwa mawonekedwe a viscoelastic a dongosololi, zimatsimikiza mwachindunji kapangidwe ka thovu lomaliza, kukhazikika kwa mawonekedwe, ndi mtundu wonse wa chinthucho.