Girazi shanduko yetembiricha tsananguro
Girazi-Shanduko Temperature (Tg), ndiyo tembiricha apo polima inoshanduka kubva payakatsetseka kuenda kune ine girazi, Zvinoreva kushanduka tembiricha yeamorphous polymer (kusanganisira iyo isiri-crystalline chikamu mucrystalline polymer) kubva munzvimbo ine girazi. kusvika kune yakanyanyisa elastic state kana kubva kune yekupedzisira kuenda kune yekutanga.Ndiyo tembiricha yakaderera apo macromolecular zvikamu zveamorphous polymers zvinogona kufamba zvakasununguka.Kazhinji Inomiririrwa naTg.Inosiyana zvichienderana nenzira yekuyera uye mamiriro.
Ichi chiratidzo chakakosha chekuita chepolymers.Pamusoro pekushisa uku, iyo polymer inoratidza elasticity;pazasi tembiricha iyi, iyo polymer inoratidza brittleness.Inofanirwa kutariswa kana ichishandiswa semapurasitiki, rabha, mafiber ekugadzira, nezvimwewo. Semuenzaniso, tembiricha yegirazi yepolyvinyl chloride i80 ° C.Zvisinei, haisi iyo yepamusoro muganhu wekushisa kwekushanda kwechigadzirwa.Semuenzaniso, tembiricha yekushanda yerabha inofanirwa kunge iri pamusoro peiyo tembiricha yegirazi, zvikasadaro icharasikirwa nekukwirira kwayo.
Nekuda kwekuti mhando yepolymer ichiri kuchengetedza hunhu hwayo, iyo emulsion inewo tembiricha yekuchinja kwegirazi, inova chiratidzo chekuoma kwefirimu rekuputira rakagadzirwa nepolymer emulsion.Iyo emulsion ine yakakwira girazi tembiricha yekuchinja ine kuvharika nekuoma kwakakwira, kupenya kwakakwirira, kunaka kwemavara, uye haisi nyore kusvibisa, uye mamwe ma mechanical properties anowirirana zviri nani.Nekudaro, tembiricha yekuchinja yegirazi uye tembiricha yayo yekugadzira firimu yakakwira zvakare, izvo zvinounza mamwe matambudziko ekushandisa pakudziya kwakaderera.Uku kupokana, uye kana iyo polymer emulsion inosvika kune imwe girazi tembiricha yekuchinja, mazhinji ezvivakwa zvayo achachinja zvakakosha, saka tembiricha yakakodzera yegirazi inofanirwa kudzorwa.Nekuda kwedhaka repolymer-modified, kukwirisa tembiricha yegirazi, kunowedzera simba rekumanikidza redhaka rakagadziridzwa.Iyo yakaderera tembiricha yekuchinja kwegirazi, zviri nani kuderera-kupisa kwekuita kwedhaka rakagadziridzwa.
Minimum film kugadzira tembiricha tsananguro
Minimum Film Kugadzira Temperature yakakoshachiratidzo chevhu rakaoma rakasanganiswa
MFFT inoreva tembiricha shoma apo mapolymer particles mu emulsion ane mafambiro akakwana ekuungana pamwe chete kuti agadzire firimu rinoenderera.Mukuita kwepolymer emulsion ichigadzira firimu rinoramba rakaputirwa, zvikamu zvepolymer zvinofanirwa kuumba hurongwa hwakanyatsorongedzerwa.Nokudaro, kunze kwekupararira kwakanaka kwemulsion, mamiriro ekugadzira firimu inoenderera anosanganisirawo deformation ye polymer particles.Kureva kuti, kana capillary pressure yemvura ichiita kudzvinyirirwa kukuru pakati pezvimedu zvedenderedzwa, padyo nekurongeka kwezvimedu zvedenderedzwa, kunowedzera kudzvanywa.
Kana zvimedu zvacho zvasangana, kudzvinyirirwa kunokonzerwa nekuputika kwemvura kunomanikidza zvimedu kuti zvisvinwe uye zviremara kuti zvibatane kuti zvigadzire firimu rekuputira.Zviripachena, kune emulsion ine maajenti akaoma, mazhinji epolymer particles ari thermoplastic resins, kudzika kwetembiricha, kuomarara kwakanyanya uye kuoma kwazvinozoita kuremara, saka pane dambudziko rekushomeka kwekushisa kwekugadzira firimu.Ndiko kuti, pasi peimwe tembiricha, mushure mekunge mvura iri mu emulsion ichibuda, mapolymer particles achiri mu discrete state uye haagone kubatanidzwa.Nokudaro, emulsion haigoni kuumba chifukidzo cheyunifomu chinoramba chiripo nekuda kwekubuda kwemvura;uye Pamusoro peiyi tembiricha chaiyo, kana mvura yanyunguruka, mamorekuru ari muchikamu chimwe nechimwe chepolymer achapinda, opararira, agokanganisa, uye oungana kuti aumbe firimu rinoramba riri pachena.Uyu muganho wakaderera wetembiricha paunogona kugadzirwa firimu unodaidzwa kuti tembiricha yekuumba firimu shoma.
MFFT chiratidzo chakakosha chepolymer emulsion, uye zvinonyanya kukosha kushandisa emulsion panguva yakaderera tembiricha mwaka.Kutora matanho akakodzera kunogona kuita kuti emulsion yepolymer ive nehushoma hwekugadzira firimu inoenderana nezvinodiwa zvekushandisa.Semuenzaniso, kuwedzera plasticizer kune emulsion kunogona kupfavisa iyo polymer uye zvakanyanya kuderedza kushoma firimu-kuumba tembiricha ye emulsion, kana kugadzirisa kushoma firimu-kuumba tembiricha.Yakakwira polymer emulsions inoshandisa additives, nezvimwe.
Iyo MFFT yeLongouVAE redispersible latex podakazhinji iri pakati pe0°C ne10°C, imwe yakajairika i5°C.Panguva iyi tembiricha, thepolima hupfuinopa firimu rinoenderera.Pane zvinopesana, pasi pekushisa uku, iyo firimu ye redispersible polymer powder haisisiri kuenderera mberi uye inoputika.Saka, iyo shoma yekugadzira firimu yekushisa chiratidzo chinomiririra kupisa kwekuvaka kweprojekti.Kazhinji kutaura, kudzikisa tembiricha yekugadzira firimu, zvinoita nani kushanda.
Kusiyana pakati peTg neMFFT
1. Tembiricha yekuchinja kwegirazi, tembiricha panopfava chinhu.Kunyanya inoreva tembiricha iyo amorphous polymers inotanga kupfava.Izvo hazvisi chete zvine chekuita nechimiro chepolymer, asiwo kune yayo molecular uremu.
2.Softening point
Zvinoenderana neakasiyana ekufamba kwemapolymers, zvinhu zvakawanda zvepolymer zvinogona kunge zviri muzvikamu zvina zvinotevera zvemuviri (kana mekiniki nyika): girazi mamiriro, viscoelastic state, yakanyanya elastic state (rubber state) uye viscous flow state.Girazi shanduko ishanduko pakati peyakanyanya elastic state uye yegirazi state.Kubva pane mamorekuru chimiro chemaonero, tembiricha yegirazi inzvimbo yekuzorora yeamorphous chikamu chepolymer kubva munzvimbo yechando kuenda kune yakanyungudika, kusiyana nechikamu.Pane chikamu chekuchinja kupisa panguva yekushandura, saka ishanduko yechipiri chikamu (inonzi primary shanduko mupolymer dynamic mechanics).Pazasi pegirazi tembiricha yekuchinja, iyo polymer iri mune girazi mamiriro, uye mamorekuru cheni uye zvikamu hazvigone kufamba.Maatomu chete (kana mapoka) anoumba mamorekuru ndiwo anodedera paakaenzana;nepo pagirazi rekuchinja tembiricha, kunyange mamorekuru maketani Izvo hazvigone kufamba, asi zvikamu zveketani zvinotanga kufamba, zvichiratidza yakakwirira elastic properties.Kana tembiricha yakawedzera zvakare, iyo yese molecular cheni ichafamba uye inoratidza viscous kuyerera zvivakwa.Girazi shanduko yekushisa (Tg) chinhu chakakosha chemuviri chivakwa cheamorphous polymers.
Girazi shanduko tembiricha ndeimwe yemhando tembiricha yemapolymers.Kutora tembiricha yegirazi yekuchinja semuganho, mapolymers anoratidza akasiyana emuviri zvimiro: pazasi pegirazi rekuchinja tembiricha, iyo polymer zvinhu ipurasitiki;pamusoro pegirazi tembiricha yekuchinja, iyo polymer zvinhu irabha.Kubva pamaonero einjiniya mashandisirwo, muganho wepamusoro wekushandiswa tembiricha yegirazi shanduko yeinjiniya mapurasitiki ndiwo muganho wakaderera wekushandiswa kwerabha kana elastomers.
Nguva yekutumira: Jan-04-2024