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Ingabe izinto ze-polyurethane zimelana namazinga okushisa aphezulu? Ngokuvamile, i-polyurethane ayimelana namazinga okushisa aphezulu, noma ngohlelo olujwayelekile lwe-PPDI, umkhawulo wawo wokushisa angaba cishe ku-150 ° kuphela. Izinhlobo ezejwayelekile ze-polyester noma ama-polyther kungenzeka zingakwazi ukubekezelela amazinga okushisa angenhla kwe-120 °. Kodwa-ke, i-polyurethane iyi-polymer enhle kakhulu, futhi iqhathaniswa nepulasitiki ejwayelekile, iyamelana kakhulu nokushisa. Ngakho-ke, ukuchaza uhla lokushisa lokumelana okushisa kakhulu noma ukwahlukanisa ukusetshenziswa okuhlukile kubalulekile kakhulu.
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Ngakho-ke ukuqina okushisayo kwezinto ze-polyurethane kungathuthukiswa kanjani? Impendulo eyisisekelo ukukhulisa i-crystaltaltity yezinto ezibonakalayo, njenge-PPDI esocyanate evame kakhulu okukhulunywe ngayo ekuqaleni. Kungani kukhulisa i-polymer crystallity ithuthukisa ukuqina kwayo okushisayo? Impendulo yaziwa ngokuphelele kuwo wonke umuntu, okungukuthi, isakhiwo sinquma izakhiwo. Namuhla, singathanda ukuzama ukuchaza ukuthi kungani ukuphuculwa kwesakhiwo samangqamuzana kuletha ukuthuthuka kokuqina okushisayo, umbono oyisisekelo usuka encazelweni noma ifomula ye-GIBBS yamandla, ie △ g = h-st. Uhlangothi lwesobunxele lwe-G lumelela amandla amahhala, futhi uhlangothi lwesokunene lwe-equation H luyi-entropy, kanye ne-T izinga lokushisa.
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I-Gibbs Free Energy ngumqondo wamandla ku-thermodynamics, futhi usayizi wawo uvame ukubaluleka okuhlobene, okusho umehluko phakathi kwamanani okuqala nokuphela, ngakho-ke i-abspect △ isetshenziswa ngqo noma imelelwe ngqo. Lapho △ g incipha, okungukuthi uma kungalungile, kusho ukuthi ukusabela kwamakhemikhali kungavele kwenzeke noma kube kuhle ekuphenduleni okuthile okulindelwe. Lokhu kungasetjenziswa ukunquma ukuthi ngabe ukusabela kukhona noma kubuye kubuye ku-thermodynamics. Izinga noma izinga lokuncishiswa lingaqondakala njengoba ama-kinetics e-reaction uqobo. H ngokuyisisekelo senthalpy, okungaqondwa cishe njengamandla angaphakathi we-molecule. Ingaqagelwa cishe kusukela ebusweni bezinhlamvu zamaShayina, njengoba umlilo awekho

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I-S imele i-entropy yohlelo, evame ukwaziwa futhi okushiwo ngokoqobo kucace bha. Kuhlobene noma kuvezwe ngokuya ngamazinga okushisa t, futhi nencazelo yaso eyisisekelo kuyindlela yokuphazamiseka noma inkululeko yohlelo oluncane lwe-microscopic. Ngalesi sikhathi, kungenzeka ukuthi umngani omncane oqaphile angabona ukuthi izinga lokushisa t lihlobene nokumelana okushisayo esikuxoxwe ngakho namuhla ekugcineni kwavela ekugcineni. Ake ngibheke nje kancane ngomqondo we-entropy. I-Entropy ingaqondakala ngobuwula njengokuphambene ne-crystallity. Inani eliphakeme le-Entropy, okuhlaselwe kakhulu futhi kunesiphithiphithi isimo se-molefanelar. Lapho kukhuphuka isimo sesakhiwo samangqamuzana, kungcono i-molecule's Crystallity. Manje, ake sinqume isikwele esincane ngaphandle kwe-polyurethane rubber roll bese ubheka isikwele esincane njengohlelo oluphelele. Isisindo sayo silungisiwe, sicabanga ukuthi isikwele senziwa ama-molecule ayi-100 e-polyurethane (empeleni, kukhona abaningi) i-Gibbs Free Energy formula ingaguqulwa, lapho i-Gibbs Free Energy formula ingaguqulwa ibe yi-st = h, lapho i-t i-entropy. Okungukuthi, ukumelana okushisayo kwe-polyurethane Square encane kulingana ne-Enthalpy H futhi kulingana kakhulu ku-entropy S. Yebo, le yindlela esondele, futhi kungcono ukwengeza △ ngaphambi kwayo (futhi kungcono ukuqhathanisa).
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Akunzima ukuthola ukuthi ukuthuthukiswa kwe-crystallity akunakunciphisa inani le-entropy kodwa futhi kwandise inani le-molelpy ngenkathi kuncipha kokushisa okusebenzayo futhi okujwayelekile, kungakhathalekile ukuthi ngabe u-T ukuguquguquka kwezinguquko. Okudinga ukuguqulwa yilokho okwenzeka njalo kanye ne-crystaltaltity yesakhiwo samangqamuzana e-monomer kanye nokujwayelekile kanye ne-crystaltaltity of the sloleture acolication ngemuva kokuhlangana noma ukuqonda ngendlela eqondile. I-Enthalpy H inikelwa ikakhulukazi ngamandla wangaphakathi we-molecule, namandla angaphakathi we-molecule kungumphumela wezakhiwo ezihlukene zamangqamuzana ezinamandla ahlukene angaba namandla amangalisa, futhi kulula ukukhiqiza i-crystallization permomena, njengamanzi adonsele eqhweni. Ngaphandle kwalokho, sivele sacabanga ngamangqamuzana ayi-100, amabutho wokuxhumana phakathi kwalawa ma-molecule ayi-100 azothinta futhi ama-roller ama-hydrogen, kepha anciphise ama-molecula bond, anciphise ama-moleculane molecule ngamunye we-polyurethane molecule ngayinye, ngakho I-Hydrogen Bond inenzuzo ekwenzeni ngcono ukumelana nokushisa.