Inkcazo yobushushu benguqu yeglasi
Ubushushu beGlasi-Transition (Tg), liqondo lobushushu apho ipholima itshintsha ukusuka kwimo eelastiki ukuya kwimo yeglasi, Ibhekisa kubushushu benguqu yepolymer eamorphous (kubandakanywa nenxalenye engeyiyo icrystalline kwipolima eyikristale) ukusuka kwimo yeglasi. ukuya kwimo enwebeka kakhulu okanye ukusuka kweyamva ukuya kweyokuqala. Lelona qondo lobushushu lisezantsi apho amacandelo e-macromolecular of amorphous polymers anokuthi ahambe ngokukhululekileyo. Ngokuqhelekileyo Imelwe nguTg. Iyahluka ngokuxhomekeke kwindlela yokulinganisa kunye neemeko.
Esi sisalathisi somsebenzi obalulekileyo weepolymers. Ngaphezulu kolu bushushu, ipholima ibonisa ukuqina; ngezantsi kobu bushushu, ipholima ibonisa ukuba brittleness. Kufuneka ithathelwe ingqalelo xa isetyenziswa njengeeplastiki, irabha, iintsinga ezenziweyo, njl. Nangona kunjalo, ayingomda ophezulu wobushushu bokusebenza kwemveliso. Ngokomzekelo, iqondo lokushisa elisebenzayo lerabha kufuneka libe ngaphezu kweqondo lokushisa lokutshintsha kweglasi, ngaphandle koko liya kulahlekelwa yi-elasticity ephezulu.
Ngenxa yokuba uhlobo lwepolymer lusagcina indalo yalo, i-emulsion nayo ineqondo lokushisa lokutshintsha kweglasi, nto leyo isalathiso sobunzima befilimu yokugquma eyenziwe yi-polymer emulsion. I-emulsion enobushushu obuphezulu beglasi eguqukayo ineengubo ezinobulukhuni obuphezulu, isicwebezelisi esiphakamileyo, ukuchasana kwamabala, kwaye akukho lula ukungcolisa, kunye nezinye iipropathi zayo zoomatshini zingcono ngokuhambelanayo. Nangona kunjalo, iqondo lokushisa lokutshintsha kweglasi kunye nobushushu obuncinci bokwenza ifilimu buphezulu, nto leyo izisa iingxaki ezithile zokusebenzisa kumaqondo aphantsi. Oku kukuphikisana, kwaye xa i-emulsion ye-polymer ifikelela kwiqondo elithile lokutshintsha kweglasi, ezininzi iimpawu zayo ziya kutshintsha ngokubalulekileyo, ngoko ke iqondo lokushisa elifanelekileyo leglasi kufuneka lilawulwe. Ngokubhekiselele kudaka olulungisiweyo lwepolymer, kokukhona ubushushu beglasi benguquko buphezulu, kokukhona amandla acinezelayo odaka olulungisiweyo. Okuya kusezantsi kweqondo lobushushu begilasi, kokukhona ubushushu obuphantsi bokusebenza kodaka olulungisiweyo.
Ubuncinci benkcazo yobushushu bokwenza ifilimu
Ubuncinci boBubushushu bokwenza ifilimu bubalulekileisalathisi sodaka olomileyo oluxutyiweyo
I-MFFT ibhekisela kwiqondo lokushisa elincinci apho amaqhekeza e-polymer kwi-emulsion anokunyakaza okwaneleyo ukuba aglomerate kunye nomnye ukwenza ifilimu eqhubekayo. Kwinkqubo ye-emulsion ye-polymer eyenza ifilimu yokugqoka eqhubekayo, iinqununu ze-polymer kufuneka zenze ilungiselelo elisondeleyo. Ngoko ke, ngaphezu kokusasazwa kakuhle kwe-emulsion, iimeko zokwenza ifilimu eqhubekayo nazo zibandakanya ukuguqulwa kweengqungquthela zepolymer. Oko kukuthi, xa uxinzelelo lwe-capillary lwamanzi luvelisa uxinzelelo olukhulu phakathi kwamasuntswana angama-spherical, ngokusondeleyo amasuntswana angama-spherical alungelelaniswa, kokukhona ukwanda koxinzelelo.
Xa iinqununu zidibana nomnye, uxinzelelo oluveliswa yi-volatilization yamanzi lunyanzela iinqununu ukuba zicinezelwe kwaye zikhubazeke ukuze zidibanise omnye nomnye ukuze zenze ifilimu yokugqoka. Ngokucacileyo, kwii-emulsions ezineejenti eziqinileyo, uninzi lwamasuntswana epolymer ziiresin ze-thermoplastic, ubushushu obusezantsi, ukuqina okukhulu kwaye kuya kuba nzima ukonakala, ngoko ke kukho ingxaki yobuncinci bobushushu bokwenza ifilimu. Okokuthi, ngaphantsi kweqondo lokushisa elithile, emva kokuba amanzi e-emulsion ephuphuma, iinqununu ze-polymer zisekwimeko ecacileyo kwaye azikwazi ukuhlanganiswa. Ngoko ke, i-emulsion ayikwazi ukwenza i-coating efanayo eqhubekayo ngenxa yokuphuma kwamanzi; kwaye Ngaphezulu kolu bushushu bukhethekileyo, xa amanzi ephuphuma, iimolekyuli kwisuntswana lepolymer nganye ziya kungena, zisasazeke, zigqwese, kwaye zidibanise ukwenza ifilimu ecacileyo eqhubekayo. Lo mda usezantsi weqondo lobushushu apho ifilimu inokwenziwa khona ubizwa ngokuba liqondo lobushushu elisezantsi lefilimu.
I-MFFT luphawu olubalulekileyo lwei-emulsion yepolymer, kwaye kubaluleke kakhulu ukusebenzisa i-emulsion ngexesha lobushushu obuphantsi. Ukuthatha amanyathelo afanelekileyo kunokwenza i-emulsion ye-polymer ibe neqondo lokushisa elincinci lefilimu elihlangabezana neemfuno zokusetyenziswa. Ngokomzekelo, ukongeza i-plasticizer kwi-emulsion inokunciphisa i-polymer kwaye inciphise kakhulu iqondo lokushisa elincinci lefilimu ye-emulsion, okanye ulungelelanise iqondo lokushisa elincinci lefilimu. Iipolymer emulsions eziphezulu zisebenzisa izongezo, njl.
I-MFFT yaseLongouI-VAE ephinda ihlakazwe ngumgubo welatexngokuqhelekileyo iphakathi kwe-0°C kunye ne-10°C, enye ixhaphake kakhulu ngu-5°C. Kweli qondo lobushushu, iipolymer powderibonisa ifilimu eqhubekayo. Ngokuchasene noko, ngaphantsi kweli qondo lokushisa, ifilimu ye-polymer powder edibeneyo ayisekho ngokuqhubekayo kwaye iphule.Ngoko ke, iqondo lokushisa elincinci lefilimu liyisalathisi esibonisa ukushisa kweprojekthi. Ngokuqhelekileyo, okukhona usezantsi ubuncinci bobushushu bokwenza ifilimu, kokukhona ukusebenza ngcono.
Umahluko phakathi kwe-Tg kunye ne-MFFT
1. Ubushushu bokutshintsha kweglasi, iqondo lobushushu apho into ithambisayo. Ikakhulu ibhekisa kwiqondo lobushushu apho iipholima ze-amorphous ziqala ukuthamba. Ayihambelani kuphela nesakhiwo sepolymer, kodwa kunye nobunzima bayo bemolekyuli.
2.Indawo yokuthambisa
Ngokwamandla ahlukeneyo ashukumayo eepholima, uninzi lwemathiriyeli yepolima idla ngokuba kwezi meko zine zilandelayo zomzimba (okanye iimeko zomatshini): imo yeglasi, imo ye-viscoelastic, imo enwebeka kakhulu (imeko yerabha) kunye nemo yokuqukuqela kwe-viscous. Utshintsho lweglasi lutshintsho phakathi kwemeko enwebeka kakhulu kunye neglasi. Ukusuka kwimbono yesakhiwo semolekyuli, iqondo lokushisa lokutshintsha kweglasi yinto yokuphumla yenxalenye ye-amorphous yepolymer ukusuka kwimeko enomkhenkce ukuya kwimo enyibilikisiweyo, ngokungafaniyo nesigaba. Kukho ubushushu besigaba sokutshintsha ngexesha lokuguqulwa, ngoko ke lutshintsho lwesigaba sesibini (esibizwa ngokuba yinguqu ephambili kwi-polymer dynamic mechanics). Ngaphantsi kweqondo lokushisa lokutshintsha kweglasi, i-polymer ikwimeko yeglasi, kwaye amakhonkco e-molecular kunye namacandelo awakwazi ukuhamba. Kuphela ziiathom (okanye amaqela) ezenza iimolekyuli ezingcangcazelayo kwindawo yazo zolingano; ngelixa kwiqondo lokushisa lokutshintsha kweglasi, nangona i-molecular chains Ayinakuhamba, kodwa iinqununu zekhonkco ziqala ukuhamba, zibonisa iimpawu eziphezulu ze-elastic. Ukuba ubushushu buyanda kwakhona, yonke ikhonkco le-molecular iya kuhamba kwaye ibonise iimpawu zokuhamba kwe-viscous. Iqondo lokushisa lokutshintsha kweglasi (Tg) liyipropathi ebalulekileyo ebonakalayo yeepolymers ze-amorphous.
Iqondo lobushushu leglasi lelinye lamaqondo obushushu eempawu zeepolima. Ukuthatha iqondo lokushisa lokutshintsha kweglasi njengomda, iipolymers zibonisa iimpawu zomzimba ezahlukeneyo: ngaphantsi kweqondo lokushisa lokutshintsha kweglasi, i-polymer material yiplastiki; ngaphezu kobushushu beglasi yokutshintsha, izinto zepolymer yirabha. Ngokombono wezicelo zobunjineli, umda ophezulu wokusetyenziswa kweqondo lokushisa kweglasi yokutshintsha ubushushu bobunjineli beplastiki ngumda ophantsi wokusetyenziswa kwerabha okanye i-elastomers.
Ixesha lokuposa: Jan-04-2024